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20220109 - Geotech · OPW23/0182
Attached to the e-mail Operational Works Application OPW23/0182 - 21 Maher Tce, Sunshine Beach QLD 4567 (Email 2 of 4).
Attached to the e-mail Operational Works Application OPW23/0182 - 21 Maher Tce, Sunshine Beach QLD 4567 (Email 1 of 4).
GEOTECHNICAL INVESTIGATION
Proposed Residence
21 Maher Terrace, Sunshine Beach
Report for: Libby & Greg Baynton
C/- Kelder Architects
21236-001-Rev0
16 July 2021
Tectonic Geotechnical Pty Ltd
PO Box 899, Buderim QLD 4556
Office: 07 5478 9016
Email: [email protected]
www.tectonicgeo.com.au
A.B.N. 83 165 727 828
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Page 2
PROPOSED RESIDENCE
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Document Review
Document No. Revision Prepared By Reviewed By Date Issued
001 0 Michael Cocks David Pollock 16 July 2021
Report Distribution
Document Revision Method of Delivery Issued To
Joel Kelder
001 0 Electronic Kelder Architects
([email protected])
Prepared By: Reviewed By:
Michael Cocks BEng (Civil/Geotechnical) MIEAust David Pollock BE(Civil) RPEQ 14121
Geotechnical Engineer Senior Geotechnical Engineer
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Report No. 21236-001-Rev0 i
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PROPOSED RESIDENCE
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Executive Summary
This report details the results of a geotechnical investigation undertaken for the proposed multi-storey
residence at 21 Maher Terrace, Sunshine Beach. The investigation was performed by Tectonic for Libby &
Greg Baynton. Kelder Architects (Kelder) are the consulting architects for the project.
The investigation comprised drilling of boreholes at two locations across accessible areas of the
development footprint, together with in-situ strength and laboratory testing. This report summarises the
results of the investigation and provides geotechnical recommendations regarding earthworks and footings,
together with temporary and permanent basement retention.
Preliminary architectural drawings indicate that development of the site will comprise the demolition of the
existing residence and pool and construction of a two-storey building, over a single level basement carpark.
No earthworks details were provided at the time of reporting; however, provided plans indicate that
excavations for the basement would likely be in the order of up to about 4 m deep in the rear daylighting at
the front, with filling less than 1 m high anticipated. Excavations will extend close to the site boundaries and
therefore, some form of temporary retention will be required.
Ground conditions in this area were expected to comprise dune sands; however, borehole drilling revealed
a sedimentary profile of residual soil over weathered sandstone. The subsurface conditions encountered in
the boreholes are summarised as follows:
Existing Fill (presumably uncontrolled) – comprising loose clayey sand to depths between
0.6 m and 0.8 m below ground level (BGL); then
Residual Soils – comprising mostly medium dense clayey sand and stiff to very stiff sandy/silty
clay of medium to high plasticity to depths between 1.2 m and 2.5 m BGL (borehole BH2
termination depth).
Extremely Weathered (XW) Materials/Sandstone – very dense clayey sand tending towards very
low strength sandstone was encountered beneath the residual soils in borehole BH1 to 4 m BGL.
The XW materials were underlain by very low strength sandstone, with auger refusal on inferred
low strength (or stronger) sandstone at 5.4 m BGL.
No signs of groundwater seepage (‘springs’) were observed during our walk-over. Groundwater was not
encountered in the boreholes at the time of investigation.
Provided the recommendations within this report are adhered to, and subject to detailed design and
construction of the footing and retention system by a suitably qualified and experienced structural engineer,
there would be a Low Risk to property from slope instability.
Excavations for the basement are anticipated to encounter some loose to medium dense sands then mostly
stiff to very stiff clays, and XW materials at depth. Excavations in such materials should be achievable using
conventional earthmoving plant (e.g. medium to large tracked excavators) with a toothed bucket, possibly
with the assistance of ripper attachments at depth or in confined areas. Temporary unsurcharged cuts in the
existing soils and weathered rock could be formed at 1V:1H, for batters up to 3 m in height, provided
groundwater seepage is not encountered. It is expected that space restrictions will limit battering of temporary
cuts on the site and so some form of temporary retention system will be required such as sheet piles.
Given the excavation depths and based on the results of the borehole drilling, stiff/medium dense (or
stronger) residual soils and possibly XW materials are expected to be exposed across the basement floor
level. In areas of shallower proposed excavations, weaker foundations may be present at subgrade level. It
is recommended that a uniform foundation is adopted across the entire building footprint to reduce
differential settlements. Depending on the design loads, high level strip and pad footings, or a stiffened raft
slab, may be adopted for the proposed basement and development. An allowable bearing pressure of
100 kPa may be adopted for high level footing design where footings are founded in stiff/medium dense (or
stronger) residual soils. Should excessive column loads preclude the use high level footings, or in areas
where unsuitable materials are exposed at the design level, deeper piled footings would be required. Please
note that as outlined in Section 6.1 an additional borehole is required following removal of the existing
residence to confirm the required foundation design parameters.
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Table of Contents
1.0 INTRODUCTION ........................................................................................................................................................ 1
2.0 PROPOSED DEVELOPMENT ................................................................................................................................... 1
3.0 METHOD OF INVESTIGATION ................................................................................................................................. 2
4.0 RESULTS OF INVESTIGATION ................................................................................................................................ 2
4.1 Site Description............................................................................................................................................. 2
4.2 Topography................................................................................................................................................... 4
4.3 Geology ........................................................................................................................................................ 5
4.4 Subsurface Conditions.................................................................................................................................. 6
4.5 Groundwater ................................................................................................................................................. 6
4.6 Surface Drainage .......................................................................................................................................... 7
5.0 SLOPE STABILITY ASSESSMENT .......................................................................................................................... 7
5.1 Existing Conditions ....................................................................................................................................... 7
5.2 Stability Assessment..................................................................................................................................... 8
5.2.1 Quantitative Assessment ........................................................................................................................ 9
6.0 GEOTECHNICAL RECOMMENDATIONS .............................................................................................................. 11
6.1 Additional Investigation ............................................................................................................................... 11
6.2 Development Limitations ............................................................................................................................ 11
6.3 Earthworks – General ................................................................................................................................. 11
6.3.1 Site Preparation and Trafficability ......................................................................................................... 11
6.3.2 Excavations ........................................................................................................................................... 12
6.3.3 Filling..................................................................................................................................................... 13
6.4 Building Foundations .................................................................................................................................. 13
6.4.1 Indicative Site Classification.................................................................................................................. 13
6.4.2 Footing Design ...................................................................................................................................... 13
6.5 Temporary and Permanent Retention......................................................................................................... 15
6.6 Drainage ..................................................................................................................................................... 16
7.0 SUMMARY & CONCLUSIONS................................................................................................................................ 17
8.0 LIMITATIONS .......................................................................................................................................................... 17
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TABLES
Table 1: Summary of Subsurface Profiles ........................................................................................................................... 6
Table 2: Stability Risk Levels .............................................................................................................................................. 8
Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007) ......................................................................... 8
Table 4: Retaining Structure Design Parameters .............................................................................................................. 16
TEXT FIGURES
Text Figure 1: Layout plan (LHS) and cross-sectional views (RHS) of proposed development, courtesy of Kelder............ 1
Text Figure 2: 2021 aerial image of the site and immediate surrounds (courtesy Nearmap imagery)................................. 3
Text Figure 3: View of the northern corner of the site, whilst drilling borehole BH1 ............................................................ 3
Text Figure 4: Panoramic view of the eastern edge of the site, looking west from Maher Terrace ..................................... 3
Text Figure 5: View of the existing pool (LHS) and longitudinal cracking in Maher Terrace (RHS) ..................................... 4
Text Figure 6: Site plan showing ground surface contours (courtesy Noosa Council ‘Intramaps’) ...................................... 4
Text Figure 7: Extract of Gympie Special 1:100,000 Geology Map ..................................................................................... 5
Text Figure 8: Medium strength sandstone exposed on upslope side of Seaview Terrace ................................................. 5
Text Figure 9: Extract from NSC landslide hazard overlay mapping ................................................................................... 7
Text Figure 10: Slope/W output for long term conditions.................................................................................................. 10
Text Figure 11: Slope/W output for short term conditions (with groundwater) ................................................................... 10
Text Figure 12: Footing depth required to prevent undermining....................................................................................... 14
FIGURES
Figure 1: Site Plan
APPENDICES
APPENDIX A
Borehole & DCP Reports & Explanatory Notes
APPENDIX B
Laboratory Test Certificate
APPENDIX C
AGS Guidelines - Qualitative Terminology for Use in Assessing Risk to Property
Some Guidelines for Hillside Construction
APPENDIX D
Limitations
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1.0 INTRODUCTION
This report details the results of a geotechnical investigation undertaken for the proposed multi-storey
residence at 21 Maher Terrace, Sunshine Beach. The investigation was performed by Tectonic for Libby &
Greg Baynton, generally in accordance with Proposal P21322-Rev0, dated 3 June 2021. Kelder Architects
(Kelder) are the consulting architects for the project.
The investigation comprised drilling of boreholes at two locations across accessible areas of the
development footprint, together with in-situ strength and laboratory testing. This report summarises the
results of the investigation and provides geotechnical recommendations regarding earthworks and footings,
together with temporary and permanent basement retention.
In summary, subject to the implementation of the recommendations made herein, it is assessed that there
would be a Low Risk of slope instability affecting the proposed development in accordance with the
Australian Geomechanics Society “Guidelines for Landslide Risk Management”, dated March 2007 (AGS
2007).
2.0 PROPOSED DEVELOPMENT
Preliminary architectural drawings were supplied to us (Ref. Kelder, Project No. 2008, Drawing Nos.
SD_0021 to SD_3000 [not inclusive], Rev A-B, dated 22 April 2021. These plans indicate that development
of the site will comprise the demolition of the existing residence and pool followed by construction of a two-
storey building, over a single level basement carpark. Construction will include a combination of masonry
and lightweight materials (e.g. weatherboard cladding to walls etc.) and suspended concrete floors.
No earthworks details were provided at the time of reporting; however, provided plans indicate that
excavations for the basement would likely be in the order of about 4 m deep in the rear with the cut
daylighting at the front. Localised filling less than 1 m high anticipated. Excavations will extend close to the
site boundaries and therefore, some form of temporary retention will be required. Isolated deeper
excavations may be required for the lift overrun pit and other elements.
Text Figure 1 below presents a layout plan and cross-sectional views of the proposed development.
Text Figure 1: Layout plan (LHS) and cross-sectional views (RHS) of proposed development, courtesy of Kelder
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3.0 METHOD OF INVESTIGATION
As part of our assessment, a desk-top study was carried out comprising a review of published geological
maps, slope stability studies as well as Noosa Shire Council (NSC) planning overlays and site information.
An experienced geotechnical engineer from Tectonic undertook a site walk-over on 22 June 2021 to visually
assess any indicators of past slope instability. The walk-over included assessment of soil exposures,
surface drainage conditions, topography, evidence of erosion or past instability, and vegetation
coverage/condition.
This was incorporated with a subsurface investigation comprising the drilling of two boreholes (designated
BH1 and BH2) in accessible areas across the site. Borehole BH1 was drilled in the northern corner of the
site using a 4WD mounted solid flight auger rig, owned and operated by Contract Drilling, to 5.4 m below
ground level (BGL). Due to access restrictions borehole BH2 was drilled to the front of the existing
residence to 2.5 m BGL using hand augering techniques.
In-situ testing, using the dynamic cone penetrometer (DCP) method, was carried out from the ground surface
and within each borehole. DCP testing was extended below the base of the hand augered borehole (BH2) to
4.3 m BGL. Boreholes were backfilled on completion with spoil arising during drilling, with excess material
slightly mounded at surface. Due to access restrictions (e.g. existing pool, gardens etc.) one additional
standalone DCP (denoted DCP3) was undertaken to the rear of the residence, which was continued to
practical refusal at 5.7 m BGL.
One selected soil sample was dispatched to a NATA accredited laboratory for geotechnical testing.
Laboratory testing was undertaken in accordance with Australian Standard AS1289 Method for Testing Soils
for Engineering Purposes and comprised Atterberg limits and particle size distribution (PSD) analyses to
assess material properties.
Borehole and DCP locations are shown in Figure 1 attached at the end of this report, with borehole and
DCP logs presented in Appendix A, together with explanatory notes. Borehole coordinates were recorded
using a handheld global positioning system (GPS).
The results of the desk-top study and walk-over survey are included in Section 4 below.
4.0 RESULTS OF INVESTIGATION
4.1 Site Description
The site is formally described as Lot 747 on RP481111, covering an area of about 550 m2, with frontage to
Maher Terrace along the north-eastern boundary. At the time of the investigation a single to double storey
residential building occupied most of the central part of the site, with access provided via a concrete
driveway directly off Maher Terrace. A pool was located in the southern corner of the site, with blockwork
retaining walls about 1 m high tracing surrounding garden beds. A timber sleeper wall about 1 m high
supported a level area adjacent to the south-eastern corner of the site, with a 1.6 m high timber sleeper wall
supporting an inferred cut beneath the northern part of the residence.
Based on a visual assessment the existing building, driveway, rear retaining walls and pool were noted to be
in good structural condition exhibiting no obvious signs of distress (e.g. cracking, misalignment, etc.) that
could be attributed to slope instability. Dilapidation was evident within the existing timber sleeper wall to the
south-east of the residence, which appeared to be related to age and poor construction as opposed to
ground movements.
Similar residential allotments with houses occupied properties to the north, south and west of the site, with
relatively dense vegetation on the opposing side of Maher Terrace to the east/north-east. Observable walls
in neighbouring residences appeared to be in relatively good structural condition, based on an external
assessment. It was noted that longitudinal cracking was evident within the asphalt seal of Maher Terrace
downslope (north) of the subject site. This cracking is consistent with creep movement in the road
embankment and/or upper natural soils. Generally, the surrounding road surface was noted to be in
relatively good condition.
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A 2021 aerial image of the site and surrounds is shown in Text Figure 2 below.
Subject Site
Text Figure 2: 2021 aerial image of the site and immediate surrounds (courtesy Nearmap imagery)
Site conditions at the time of our investigation are shown below and overleaf in Text Figures 3 to 5.
Text Figure 3: View of the northern corner of the site, whilst drilling borehole BH1
Text Figure 4: Panoramic view of the eastern edge of the site, looking west from Maher Terrace
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Text Figure 5: View of the existing pool (LHS) and longitudinal cracking in Maher Terrace (RHS)
4.2 Topography
As illustrated in Text Figure 6 below, the site is located on the north-easterly facing flank of a ridge which
crests about 200 m to the west. An inferred ancient sand dune appears to crest slightly to the south-east of
the site, with an easterly trending natural drainage line commencing slightly to the north. During the site
walk-over, topographic features specific to the site were noted, and ground slopes were recorded using a
hand-held clinometer.
The natural surface profile had been interrupted by historic landscaping and residential construction; with
inferred unaltered ground slopes along the side boundaries measured at the time of our assessment of
between about 10° and 12°. Slightly steeper ground surfaces were observed to the north of the site, ranging
between about 15° and 18°. Based on our observations it appeared that cut and fill earthworks in the order
of about 2 m deep and 1 m high had been undertaken across the site. Areas immediately surrounding the
residence were gently sloping (less than 3°), mostly supported by timber/block retaining walls. Unsupported
fill batters (less than 1 m high) were observed to the east of the residence, typically battered no steeper than
25°. The front of the property comprised moderately sloping driveway, being about 12°, down to gently
sloping ground adjacent to Maher Terrace (less than 5°).
Generally, no irregular surface features were noted across the subject site which would indicate global slope
instability.
Subject Site
Text Figure 6: Site plan showing ground surface contours (courtesy Noosa Council ‘Intramaps’)
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4.3 Geology
Available geological information 1 indicates that the site is underlain by Pleistocene age dune sand
(Ref: Text Figure 7). It should be noted that older late Triassic to Jurassic age sedimentary strata of the
Tiaro Coal Measures is mapped and daylights to the north/north-east of the site (Lion Rock).
Although dune sands were expected borehole drilling revealed a sedimentary profile of residual soil over
weathered sandstone. Massively bedded medium strength (or stronger) sandstone was observed in an
upslope cutting along Seaview Terrace to the north-west (Ref. Text Figure 8). The younger aeolian dune
sands may have been eroded from the site over geological time due to the close proximity to the nearby
natural drainage line.
Approx. Site Location
Text Figure 7: Extract of Gympie Special 1:100,000 Geology Map
Text Figure 8: Medium strength sandstone exposed on upslope side of Seaview Terrace
1
Queensland Government, Department of Mines and Energy, 1:100,000 Gympie Special Geology Map, Sheet 9445 & Part 9545, 1999
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4.4 Subsurface Conditions
Detailed descriptions of the subsurface conditions encountered in the boreholes are provided in the
borehole reports attached in Appendix A, along with definition sheets which describe terms and
abbreviations used on the reports. The subsurface conditions encountered in the boreholes are
summarised as follows:
Existing Fill (presumably uncontrolled) – comprising loose clayey sand to depths between
0.6 m and 0.8 m BGL; then
Residual Soils – comprising mostly medium dense clayey sand and stiff to very stiff sandy/silty
clay of medium to high plasticity to depths between 1.2 m and 2.5 m BGL (borehole BH2
termination depth).
Extremely Weathered (XW) Materials/Sandstone – very dense clayey sand tending towards very
low strength sandstone was encountered beneath the residual soils in borehole BH1 to 4 m BGL.
The XW materials were underlain by very low strength sandstone, with auger refusal on inferred
low strength (or stronger) sandstone at 5.4 m BGL.
We have not sighted any certification documentation regarding the existing fill, and it is taken to be
‘uncontrolled’ material in accordance with the definitions given in AS 2870-2011 Residential Slabs and
Footings.
Laboratory testing of the sample tested from borehole BH2 (1.2 to 1.5 m BGL) indicated that the material
was a sandy clay of medium to high plasticity. The laboratory test certificate is presented in Appendix B
The standalone DCP test (DCP3) undertaken to the rear of the property indicated the following subsurface
conditions:
Firm/loose materials to 0.6 m BGL; then
Stiff/medium dense materials to 4.4 m BGL; overlying
Very stiff/dense (or stronger) materials to the DCP termination depth at 5.7 m BGL.
Table 1 below, summarises the subsurface profile in each borehole.
Table 1: Summary of Subsurface Profiles
Weathered
Borehole No. Fill Residual Soils XW Materials
Sandstone
BH1 0 – 0.8 0.8 – 1.2 1.2 – 4.0 4.0 – 5.4AR
BH2 0 – 0.6 0.6 – 2.5HR NE NE
Notes: 1. Depths noted in m BGL at time of investigation (22 June 2021)
2. NE denotes not encountered
3. AR denotes borehole terminated due to auger refusal
4. HR denotes borehole terminated due to hand auger refusal
Detailed descriptions of the subsurface conditions encountered in the boreholes are provided in the borehole
reports attached in Appendix A
4.5 Groundwater
No signs of groundwater seepage (‘springs’) were observed during our walk-over. Groundwater was not
encountered in the boreholes at the time of investigation.
Groundwater conditions are expected to be reflective of prevailing weather conditions and seepage may
occur at shallower depths, and at locations not previously observed, particularly following periods of
prolonged or heavy rainfall.
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4.6 Surface Drainage
Surface drainage would be expected to follow natural surface contours to the north-east towards
Maher Terrace, thus draining into the roadside drainage system. It is noted that the site has relatively large
catchment; however, most runoff from upslope of the property is anticipated to be intercepted by the existing
stormwater infrastructure from the neighbouring structures and streets.
No significant surface run-off features were noted during our assessment (e.g. deep rilling or scour/wash out
scars). This indicates that significant overland flow is generally absent during rainfall events.
Recommendations to improve surface drainage as part of the development works are provided in
Section 6.5.
5.0 SLOPE STABILITY ASSESSMENT
5.1 Existing Conditions
The Noosa Planning Scheme 2020 includes a landslide hazard overlay map (Ref. extract in Text Figure 9).
Mapping indicates that the site is within a Moderate (pale yellow shading) to High (orange-brown shading)
Landslide Hazard Area.
Approx. Site Location
Text Figure 9: Extract from NSC landslide hazard overlay mapping
It should be noted that the Noosa landslide hazard map is a broad-scale indication of the potential
landslide susceptibility and is superseded by this site-specific assessment. Our observations of surface
features relevant to this slope stability assessment are summarised as follows:
The existing residential building was noted to be in good structural condition based on an external
assessment and showed no signs of instability (e.g. no significant cracks in rigid walls etc.).
A downslope timber sleeper wall was distressed, likely a result of age and poor construction rather
than global slope instability.
No indicators of recent global slope instability were observed, i.e., no landslide scarps or ‘hummocky’
ground was evident across the proposed building area.
No signs of groundwater seepage ‘springs’ were observed across the proposed development area.
Longitudinal cracking was observed in Maher Terrace. This cracking is consistent with creep
movement in the road embankment and/or upper natural soils; however, it was well away from the
proposed development area.
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5.2 Stability Assessment
The risk assessment for this project has been carried out following AGS 2007 Practice Note Guidelines for
Landslide Risk Management. Relative levels of risk and their implications are given in Table 2 and the
Qualitative Terminology for Use in Assessing Risk to Property is also attached in Appendix C.
Table 2: Stability Risk Levels
Risk Level Example Implications(1)
Unacceptable without treatment. Extensive detailed investigation and research, planning
Very High
VH and implementation of treatment options essential to reduce risk to Low; may be too
Risk
expensive and not practical. Work likely to cost more than value of property.
Unacceptable without treatment. Detailed investigation, planning and implementation of
H High Risk treatment options required to reduce risk to Low. Work would cost a substantial sum in
relation to the value of the property.
May be tolerated in certain circumstances (subject to regulators’ approval) but requires
Moderate
M investigation, planning and implementation of treatment options to reduce risk to Low.
Risk
Treatment options to reduce to Low risk should be implemented as soon as practicable.
Usually acceptable to regulators. Where treatment has been required to reduce the risk to
L Low Risk
this level, ongoing maintenance required.
Very Low
VL Acceptable. Manage by normal slope maintenance procedures.
Risk
Note: (1) The implications for a particular situation are to be determined by all parties to the risk assessment and may
depend on the nature of the property at risk; these are only given as a general guide.
Considering the existing site conditions (Ref. Section 2), and subject to the implementation of
recommendations given below, it is assessed that there would be a Low (L) Risk of global slope instability
affecting the proposed development. Regulators (NC) normally require that a Very Low or Low Risk of
landslide affecting the property must be demonstrated to enable development approval. Summarised in Table
3 below is our qualitative assessment of landslide risk for the development site. A summary of qualitative
terminology for use in assessing risk to property is attached (taken from AGS 2007).
Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007)
Assessed
Hazard Likelihood Consequence Risk Comments
Given the low to moderate natural gradients through
the proposed building area, it is considered Unlikely
that a landslip would develop in these materials,
1: Failure through residual soils
Unlikely Medium Low subject to implementation of the recommendations in
above the foundation depth
Section 4. Given a potential Medium impact from
such instability the resultant risk would be Low as per
AGS 2007.
The likelihood of a deep failure through the residual soils
or weathered sandstone below the proposed foundation
2: Deep failure through the
depth is assessed as Rare due to the lack of precedence
residual soils or weathered
Rare Major Low of such movements locally, no signs of any existing slope
sandstone below the foundation
instability and a lack of groundwater. Although the
depth
consequence of such a failure would be Major, the
resultant risk is Low as per AGS 2007.
The likelihood of a slip/failure through the temporary
retention system (sheet pile wall, or similar) as outlined in
3: Temporary instability through Section 6.5, is assessed as Rare, subject to detailed
solder/sheet pile temporary design by a suitable qualified RPEQ engineer and
Rare Major Low
retention system, or similar, as construction by a specialist contractor which accounts for
discussed in Section 6.5. the required factors of safety against slope instability.
Although the consequence of such a failure would be
Major, the resultant risk is Low as per AGS2007.
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The potential impacts on slope stability of the development components have been assessed, and the
measures recommended below in Section 4 have been designed to mitigate those impacts.
5.2.1 Quantitative Assessment
In order to estimate the factor of safety (FOS) against slope instability for the proposed development,
numerical analysis has been conducted using the software Slope/W. The ground surface profile has been
modelled using a combination of survey information, preliminary design drawings and slope angles
measured in the field by Tectonic. The analysed subsurface profile was compiled based on the results of our
subsurface investigation. Some inferences regarding subsurface conditions were made between test
locations. A minimum FOS value of 1.3 and 1.5 is the commonly adopted industry standard for short- and
long-term conditions, respectively.
Although no groundwater was encountered during the investigation, a piezometric line was modelled at
about 1 m below the future ground surface to replicate possible groundwater development for short-term
conditions. Should groundwater be encountered during the additional investigation, subsurface drainage has
been recommended in Section 6.6.
To replicate future landscaping, a surcharge load of 5 kPa has been applied upslope of the proposed
building. Although building loads were not available at the time of reporting; a gross building load of 20 kPa
has been applied to areas of the building likely founded using high-level footings. Other areas will be
supported by piled foundations in the underlying competent materials.
Soil shear strength was based upon effective parameters which were estimated based on our interpretation
of the subsurface investigation results, while also considering the values recommended for similar materials
in Appendix D of Australian Standard AS4678-2002 ‘Earth Retaining Structures’. Adopted soil parameters
are shown on the Slope/W outputs presented in Text Figures 10 and 11 on the following page. Analysis was
undertaken for a specified range of entry and exit points that could impact the proposed development.
The analysed profile represents the critical section (i.e. ‘worst case’ scenario) for the proposed development,
which covers the deepest cut. Our analysis indicates that the proposed development will achieve at least the
required minimum FOS for short- and long-term conditions, that being, 1.3 and 1.5, respectively.
It should be noted that this modelling addresses the global stability of the proposed works; however, the
stability of the retaining walls must be addressed by others as part of detailed design.
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Text Figure 10: Slope/W output for long term conditions
Text Figure 11: Slope/W output for short term conditions (with groundwater)
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6.0 GEOTECHNICAL RECOMMENDATIONS
General recommendations to help maintain the stability of the site are given in the document “Some
Guidelines for Hillside Construction”, which is attached.
6.1 Additional Investigation
Based on the results of the investigation and accessibility issues at the time of the investigation, a deeper
investigation is required to confirm the required footing depths for the detailed design phase. This
investigation would be undertaken following the demolition of the existing residence and would comprise the
drilling of one borehole using a 4WD mounted solid flight auger rig to depths between 6 m and 8 m BGL, or
shallower refusal. Tectonic can undertake such an investigation for an additional fee, following detailed
design drawings and demolition of the existing residence, if requested.
6.2 Development Limitations
It is anticipated earthworks will include cuts for the basement level of up to about 4 m deep in in the rear with
only minor filling expected to be required up to about 1 m in height to form finished surface levels. Should
proposed cuts/fills exceed this quantity, Tectonic must assess the impacts on slope stability before
construction.
6.3 Earthworks – General
6.3.1 Site Preparation and Trafficability
Following removal of the existing buildings and associated construction elements (e.g. footings, services,
etc.), any tree stumps and large roots should be ‘grubbed out’. Any organic rich topsoil and uncontrolled fill
should then be stripped and set aside. Based on the boreholes, topsoil stripping depths should generally
range between 0.1 m and 0.2 m BGL, with uncontrolled fill encountered to 0.8 m BGL (existing ground
levels) in borehole BH1. It is possible that deeper pockets of topsoil or uncontrolled fill may exist and
deeper, localised grubbing out of tree roots may be required.
Topsoil materials must not be used in structural fill; however, may be placed across landscaping areas.
Unsuitable natural material such as any saturated, loose or soft materials encountered should also be
removed during subgrade preparation for bulk earthworks.
After stripping and excavations to design levels, the subgrade is generally expected to comprise stiff to very
stiff residual clays, medium dense (or denser) sands and possibly weathered sandstone. Although relatively
good trafficability should be encountered during ‘dry’ weather conditions, the clayey soils could be subject to
strength loss from repetitive vehicle loading (particularly from rubber tyred plant) or if they become wet.
Placement of imported rock (about 150 mm thick) may be required to provide stable access along high traffic
areas, or on steeper gradients (e.g. access ramps), particularly following periods of heavy or prolonged
rainfall.
Following bulk excavation, the subgrade must be inspected by a suitably qualified and experienced RPEQ
geotechnical engineer (‘Geotechnical Engineer’) to determine whether any over-excavation is required to
achieve a stable subgrade for construction activities, and a suitable subgrade for the selected foundation
system (Ref. Section 6.4.2).
Groundwater seepage was not encountered during the investigation; however, depending on the prevailing
weather conditions at the time of construction groundwater seepage may be encountered at shallower
depths.
The site should be graded to shed surface water runoff away from construction areas. Swale drains should
be constructed along the toes of any cuts, and above cuts where possible, with the drains graded to
discharge collected waters to a control point before release off-site. Appropriate erosion and sediment
control measures must be installed prior to commencement of earthworks at this site.
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PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
Specific design would need to be carried out to determine working platform requirements for any heavy plant
(e.g. mobile cranes), and a thicker rock fill platform may be required than recommended above, particularly if
established at ground level on adjoining land.
6.3.2 Excavations
Provided plans indicate that excavations in the order of about 4 m deep will be required for the proposed
basement. Excavations to this depth are anticipated to encounter mostly stiff to very stiff clays, loose to
medium dense sands and XW materials at depth. Excavations in such materials should be achievable
using conventional earthmoving plant (e.g. medium to large tracked excavators) with a toothed bucket,
possibly with the assistance of ripper attachments at depth or in confined areas.
Although not expected to the proposed excavations depths, should very low strength (or stronger) sandstone
be encountered during basement excavations, the use of larger earthmoving plant with ripper and/or
hydraulic rock breaking attachments may be required, particularly for any confined excavations (e.g. lift pit
overruns). Should any medium strength (or stronger) rock be encountered, the use of hydraulic rock
breaking or more specialised excavation techniques (e.g. pre-splitting using expansive grout) may be
required. Apart from rock strength, excavatability of the weathered rock will be dependent upon the
frequency and continuity of joints within the rock mass.
Any excavation required adjacent to existing structures/infrastructure will need to be specifically designed to
ensure that the structures are not adversely affected (e.g. ‘undermined’). Prior to bulk earthworks, it is
recommended that footing exposures or confirmation of foundations via certified building plans be
undertaken to assess the possibility of undermining. If undermining is a potential issue the existing
structures may need to be underpinned or excavations may require temporary shoring. The advice of a
suitably qualified and experienced RPEQ structural engineer must be sought regarding any potential
undermining, along with the design and construction of any underpins or shoring (if required).
Care would need to be taken during installation of the selected retention system and excavation to the
design levels to manage potential vibration impacts on nearby structures. It would be prudent to conduct a
dilapidation survey of adjacent structures (including internal walls) prior to commencement of the site works,
then ground vibration monitoring during construction.
Where battering is achievable during construction, temporary batter slopes of 1V:1H would be acceptable for
the materials encountered in the boreholes, provided groundwater is not encountered, and no surcharging of
batters is affected. This would be applicable over a maximum excavation depth of 4 m. Deeper cuts, if
required, should be specifically assessed by Tectonic.
If filling or permanent cuts exceed 1 m, then these must be retained. Permanent cut and fill batters up to
1 m high shall not exceed 1V:2.5H. Any permanent soil and fill batters will require erosion protection (e.g.
revegetation or surface protection).
It is likely that above temporary batter slopes will not be able to be achieved, due to spatial restraints, and so
temporary shoring will be required (e.g. sheet piles) as per the recommendations in Section 6.5 below.
The above recommendations do not supersede any existing safety regulations or legislation applicable to
excavations (e.g. limits on personnel entry into trenches).
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PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
6.3.3 Filling
Excluding topsoil and any over-wet soils, the existing soils where free of deleterious materials (e.g.
vegetation, cobbles/boulders etc.) are expected to be suitable for re-use as structural fill, subject to
appropriate moisture adjustment. Due to the mostly highly plastic and potentially highly reactive nature of
the clays encountered, careful handling and placement would be required when reusing the site won clays,
with adverse impacts due to potential high shrink-swell to be considered (particularly for pavement and
building design).
Should importation of fill be required, it is recommended that such fill should comply with the following:
Minimum CBR of 10%
Maximum plasticity index of 15%
Shrink-swell index ≤ 1%
Maximum particle size of 100 mm
Any fill should be compacted at moisture contents within the range of ±2% of optimum moisture content for
Standard Compaction. Fill material should be placed in 250 mm thick (loose thickness) layers and be
compacted by repeated rolling using a minimum 4 tonne smooth drum roller (or equivalent, with vibration on
if safe to do so) to achieve a dry density ratio of at least 98% of the maximum Dry Density Ratio (DDR),
based upon the Standard Compaction method, or a Dry Density Index of at least 75%.
Confirmatory compaction testing must be carried out at regular intervals. A minimum of two tests per vertical
lift is recommended where structural fill heights are to exceed 300 mm. Further details for control and testing
of fill are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and
Residential Developments.
Fill embankment edges must be over-filled by 0.5 m (horizontally) and then trimmed back to well compacted
material.
6.4 Building Foundations
6.4.1 Indicative Site Classification
Site classifications for footing design are determined in accordance with AS 2870-2011 Residential Slabs and
Footings, and depend on the depth of cut / fill undertaken at a site, variations in the natural soil/rock depths,
and the reactivity of the in situ soil / rock and any imported fill materials.
Based on the results of the investigation, the site is classified as Class P in accordance with AS 2870-2011
Residential Slabs and Footings, due to the presence of uncontrolled fill and poor bearing capacity soils at
shallow depths. However, if not for these factors, the site would have the characteristics of Class M, with the
estimated characteristic surface movements (‘ys’) ranging up to about 40 mm. A site classification of Class M
is recommended in relation to assessment of flexibility requirements for ground slab, footing and plumbing
design.
It should be noted that placement of highly reactive clay fill may have an adverse impact on the site
classification (i.e. Class H1 or higher).
6.4.2 Footing Design
Given the excavation depths and based on the results of the borehole drilling, stiff/medium dense (or
stronger) residual soils and possibly XW materials are expected to be exposed across the basement floor
level. In areas of shallower proposed excavations, weaker foundations may be present at subgrade level. It
is recommended that a uniform foundation is adopted across the entire building footprint to reduce
differential settlements.
Depending on the design loads, high level strip and pad footings, or a stiffened raft slab, may be adopted for
the proposed basement and development. An allowable bearing pressure (ABP) of 100 kPa may be
adopted for high level footing design where footings are founded in stiff/medium dense (or stronger) residual
soils.
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PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
Should excessive column loads preclude the use high level footings, or in areas where unsuitable materials
are exposed at the design level, deeper piled footings would be required. Piles could be designed on the
following ABPs:
0.5 m into stiff/medium dense residual soils – ABP 150 kPa.
0.5 m into very stiff/dense residual soils – ABP 300 kPa.
0.3 m into XW materials or very low strength sandstone – ABP 600 kPa.
Please note that as outlined in Section 6.1 an additional borehole is required to be drilled following removal
of the existing residence to confirm the required foundation design parameters.
Due to close proximity to the surrounding properties driven piles are not considered to be suitable for this
site. Based on the ground conditions encountered, steel reinforced concrete bored piles or steel screw piles
could be utilised. Should loose sands or groundwater seepage be encountered during piling sacrificial liners
(e.g. formatube etc.) and dewatering equipment may be required for bored piles. The advice of a specialist
piling contractor must be sought regarding feasibility, design and installation of the piling system for this site,
including an assessment of potential vibration effects on nearby structures, and monitoring requirements.
Any foundation subgrades and footing excavations must be inspected by a suitably qualified and
experienced Geotechnical Engineer to confirm the foundation materials and allowable bearing capacity, and
to advise on treatment of any unsuitable zones if encountered.
Resultant settlements from footings founded as described above should be within serviceability limits,
estimated to be less than 25 mm or 1% of footing width. Settlement estimations will need to be confirmed
once working wall and column loads are available.
Footing design should also account for potential soil reactivity to be equivalent to Class M. It should be noted
that placement of reactive clay may result in a more severe equivalent site classification, such as H1 or
greater.
All footings should found such that they are not adversely affected by any adjacent excavations, batter
slopes, trenches, retaining walls, or in ground structures that are not designed to support building loads.
Footings should found at least below a plane extending 1 m horizontally from the base of
trenches/excavations/retaining walls/swimming pool, then rising up at 1V:1H, as illustrated in Text Figure 12
overleaf.
Text Figure 12: Footing depth required to prevent undermining
Site drainage should be designed to readily remove surface water and to prevent ponding of water on
subgrade areas during construction and also adjacent to foundations and perimeter slabs once construction
is completed. It is recommended that footings be inspected by a suitably qualified and experienced engineer
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PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
prior to placement of steel reinforcement and pouring of concrete to confirm allowable bearing pressures and
cleanliness of excavations.
If any soil conditions encountered during construction are found to differ from those noted in the geotechnical
investigation, Tectonic should be notified immediately and an inspection carried out to determine if changes
to footing design are required.
6.5 Temporary and Permanent Retention
Excavations are expected to be around 4 m BGL (existing ground levels) and, given that the planned extent
of the excavations extends close to some of the site boundaries, some form of temporary shoring will likely
be required to support the basement excavation.
Based upon our experience with similar sites, we anticipate that temporary shoring may be achieved by use
of sheet piles or a ‘soldier’ pile wall system. Such shoring techniques may require lateral restraint, and this is
conventionally achieved by anchoring. However, the proximity to neighbouring properties would require a
number of permissions to be obtained for subterranean access. Therefore, it is suggested that internal
struts/propping be considered to provide lateral restraint for the shoring system.
It is recommended that the excavation of a test pit(s) closer to the time of construction is undertaken to
enable further assessment of potential impacts on the shoring system from groundwater and subsurface
conditions.
Based on the results of the investigation, the following temporary retention options are considered potentially
feasible for the proposed development:
Anchored or propped sheet pile walls (limited to soils and very low strength sandstone). This
system would require pre-drilling to prevent adverse vibrations during sheet pile installation and
prevent penetration refusal on stiff residual soils or weathered sandstone. Temporary lateral
support can be provided by installation of helical steel anchors (similar to screw piles), dowels
(similar to soil nails) or internal props/struts connected to walers. As a permanent basement wall is
constructed inside the temporary structure, the sheet pile wall becomes sacrificial.
Anchored or propped ‘solider’ pile walls. Back-to-back steel C-channels (welded together with a
central spacer) would be installed in bored holes at about 2.5 m centre-to-centre spacing. These
soldier piles are typically ‘toed in’ at least 2 m below the bulk excavation level, then backfilled with
concrete to just below that level. Steel mesh or fibre reinforced shotcrete is then installed in panels
between the soldiers and may be used as the permanent basement wall (with cosmetic finishes
applied). It is anticipated that conventional auger/boring equipment would be suitable for soldier pile
installation; however, should any medium strength (or stronger) weathered sandstone be
encountered more specialised techniques may be required (e.g. pneumatic hammer drilling
equipment). Furthermore, temporary stability of the soil panels between the soldier piles may be
difficult to maintain if substantial groundwater seepage occurs during construction. A significant
advantage of the soldier pile system, as compared to sheet piles, is that it forms part of the
permanent basement structure.
Other shoring methods that could be considered include contiguous or non-contiguous piles and secant
piles. The advice of a specialist shoring contractor must be sought regarding feasibility, design and
installation of the proposed retention and subsurface drainage system. It will be necessary to conduct
numerical analysis to optimise the retention system. Detailed design will also need to account for relevant
factors of safety to maintain the temporary and long-term stability of the retention system.
Where sheet pile installation proposes pre-drilling, care would need to be taken with this, and eventual pile
driving, to manage potential vibration impacts on nearby structures, including underground service pipes
such as the sewer and stormwater to the rear. It would be prudent to conduct a dilapidation survey of such
adjacent structures prior to commencement of the site works.
Although not encountered in the preliminary investigation, groundwater may be encountered in the additional
investigation or during construction. For design purposes it would be prudent to consider the impacts of
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PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
hydrostatic pressure behind the chosen retention system, and to limit the need for extensive dewatering,
subsurface drainage may need to be implemented as follows:
Install inclined subsurface drainage (e.g. 50 mm perforated PVC pipe) at 3 m spacings, starting as
deep as possible behind the lower level retaining wall then drilled up into the slope. The inclined
drains would need to extend into the natural ground slope towards the west far enough to ensure
groundwater is intercepted at potentially higher elevations.
Pin 300 mm wide Megaflo strip drains, or similar behind the wall panels and connect into a collection
drain along the toe of the wall.
All collected groundwater from subsurface drainage is to be piped to the legal point of downstream
discharge (e.g. stormwater infrastructure along Maher Terrace).
It is anticipated that minimal groundwater seepage should migrate into the excavation area following
installation of the above subsurface drainage. Such seepage should be readily removable using a gravity
drainage or submersible sump-pump(s), at a low point in the excavation.
It is anticipated that a passive (permanent) dewatering system will be incorporated into the ground floor
system, thus enabling for design without hydrostatic pressure. This could comprise a series of drains behind
retaining walls and beneath the ground floor, connected by pipes to drain under gravity to the Council road
stormwater system (down slope).
Retaining structures greater than 1 m high, or those required to support surcharge loads or sloping backfill,
will require engineer design and certification of construction. Retaining wall design should be carried out in
accordance with AS4678-2002 Earth retaining structures.
Design for temporary and permanent retaining structures could be carried out using a trapezoidal (for
propped or anchored walls) pressure distribution applicable to the wall type and based on the parameters
listed in Table 4 overleaf. These values do not include allowance for hydrostatic pressures nor transient (e.g.
construction) or adjacent footing loadings.
Table 4: Retaining Structure Design Parameters
Lateral earth pressure coefficients
Unit
Friction
Retained material weight
angle (°) Ka Ko
(t/m3) Kp
(Cantilever wall) (Non-yielding wall)
Loose Sands 1.8 28 0.36 0.53 2.8
Stiff Clays 1.8 25 0.41 0.58 2.5
Future Controlled Fill* * * * * *
Note: * Depends on fill material type and level of compaction.
Retaining structures must be founded as per the recommendations in Section 6.4.2 above with the piled
footings, if required, also designed to resist lateral loads imposed by the retaining wall. Detailed design must
include an assessment of stability.
6.6 Drainage
Surface diversion drainage should be constructed above the crest of any new cut or fill embankment or
retaining walls (e.g. grassed or landscaped swales or diversion mounds). Adequate site drainage must be
installed to ensure that stormwater runoff is directed away from building walls, footings, batters and retaining
walls.
If groundwater seepage is encountered during excavations, Tectonic must be notified to assess the impact
on stability.
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PROPOSED RESIDENCE
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Subsurface drainage must be installed behind any retaining walls (e.g. slotted ‘aggi’ pipe wrapped in filter
‘sock’ placed in gravel backfill). Depending on matters such as the extent of drainage installed and site-
specific groundwater conditions, the designer must make an assessment of hydrostatic pressure to be
accounted for in the design of the retaining structure.
All excess stormwater collected around the residence (including overflow from rainwater tanks etc.) must be
directed by pipes or lined channels to discharge into the existing stormwater infrastructure along Maher
Terrace. Subsurface disposal of stormwater must not be undertaken.
It is anticipated that a passive (permanent) dewatering system will be incorporated under the ground floor
slab, thus enabling for design without hydrostatic pressure as outlined above in Section 6.5.
7.0 SUMMARY & CONCLUSIONS
Based on the findings of our assessment it is assessed that there would be a Low Risk of slope instability
affecting the proposed development subject to implementation of the recommendations given in this report.
8.0 LIMITATIONS
Your attention is drawn to the document “Limitations”, which is included in Appendix D of this report. The
statements presented in this document are intended to advise you of what your realistic expectations of this
report should be, and to present you with recommendations on how to minimise the risks associated with the
services provided by Tectonic for this project.
16 July 2021
Report No. 21236-001-Rev0 17
Page 23
Tectonic Geotechnical Pty Ltd
PO Box 899
Buderim Qld 4556
Ph: 07 5478 9016
PROJECT:
PROPOSED RESIDENCE
21 MAHER TERRACE,
SUNSHINE BEACH
TITLE:
SITE PLAN
BH1
CLIENT:
LIBBY & GREG BAYNTON
Subject Site BH2
DRAWN: DATE:
DCP3 MCC 16/07/2021
CHECKED: DATE:
DJP 16/07/2021
SCALE:
AS SHOWN (APPROX.)
LEGEND:
APPROX. BOREHOLE
LOCATIONS
APPROX. STANDALONE
DCP TEST
Notes:
Base plan adopted from Nearmap imagery dated 30 May 2021 0m 10 30m
PROJECT NO.: FIGURE: REV:
21236-001 1 0
Page 24
PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
APPENDIX A
Borehole & DCP Reports & Explanatory Notes
16 July 2021
Report No. 21236-001-Rev0
Page 25
Borehole No.
BH1
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: Libby & Greg Baynton Commenced: 22/6/2021
Project Name: Proposed Residence Completed: 22/6/2021
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: MCC
Hole Position: 511078.0 m E 7080008.0 m N MGA2020 Zone 56 Checked By: DJP
Drill Model and Mounting: 4WD Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Contract Drilling
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
Clayey SAND (FILL), fine to coarse grained, grey,
medium plasticity clay fines
L
HA
DS CI-CH Sandy CLAY, medium to high plasticity, pale Augered to 0.9m
VSt
0.8-1.0m brown to brown and grey, fine to medium grained
1 M
SC-SM sand MD
DS (RESIDUAL)
1.1-1.4m >20
Silty Clayey SAND, fine to coarse grained, yellow
brown, low plasticity clay fines, trace of fine to Refusal
medium sized gravel
SC
with some weak cementation
Clayey SAND, fine to medium grained, pale
yellow brown and minor red grey, low plasticity
clay fines
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 16/7/2021 08:59 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
Augered to 2.0m
AD/T
2 (EXTREMELY WEATHERED MATERIAL)
SC
Clayey SAND, fine to coarse grained, pale yellow >20
brown and pale grey, low plasticity clay fines, Refusal
Not Encountered
tending to very low strength sandstone
VD
Augered to 3.0m
3 D >20
Refusal
4
SANDSTONE, distinctly weathered, fine to
AD/V
coarse grained, yellow brown and pale grey, very
low strength
Augered to 4.5m
>20
Refusal
5
becoming very low to low strength
Hole Terminated at 5.40 m
Auger refusal on inferred low strength sandstone
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 26
Borehole No.
BH2
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: Libby & Greg Baynton Commenced: 22/6/2021
Project Name: Proposed Residence Completed: 22/6/2021
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: MCC
Hole Position: 511089.0 m E 7079989.0 m N MGA2020 Zone 56 Checked By: DJP
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Contract Drilling
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
Clayey SAND (FILL), fine to coarse grained, dark
grey, trace of rootlets, trace of fine to medium
sized gravel L
becoming dark brown
150
Sandy CLAY (FILL) medium to high plasticity,
brown, grey and pale grey, fine to medium St
Not Encountered
grained sand
1
SC Clayey SAND, fine to medium grained, dark grey, MD 250
trace of organics
DS M
HA
CI-CH (Remnant TOPSOIL)
1.2-1.5m
Sandy CLAY, medium to high plasticity, red
brown, brown, yellow brown and pale grey, fine to VSt
medium grained sand
(RESIDUAL)
250
SC Clayey SAND, fine to medium grained, red
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 16/7/2021 08:59 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
brown, yellow brown and pale grey, medium Augered to 2.0m
2 MD
plasticity clay fines
250
CH Sandy CLAY, high plasticity, red brown, yellow
brown and pale grey, fine to medium grained VSt
sand
Hole Terminated at 2.50 m
Practical hand auger refusal
3
4
>20
Refusal
5
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 27
CLIENT : Libby & Greg Baynton SHEET : 1 OF 1
CONTRACTOR :
PROJECT : Proposed Residence
LOCATION : 21 Maher Terrace, Sunshine Beach
PROJECT No. : 21236
TEST: DCP3
LOGGED: MCC 22/6/2021 CHECKED: DJP
28/6/2021
EASTING: 510087.0 m NORTHING: 7079979.0 m
Depth (m)
MGA2020 Zone 56
Blows per 100 mm (AS 1289.6.3.2-1997)
0 5 10 15 20 25
1
2
TECTONIC 3.00.2 LIB.GLB Log IS DCP 3 PER PAGE 21236.GPJ <<DrawingFile>> 16/7/2021 09:01 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
3
4
5
>15
Comments
Page 28
TERMS USED ON LOGS
DRILLING/EXCAVATION METHOD
AD* Auger Drilling RA Rotary Air BH Tractor Mounted Backhoe
ADH Hollow Auger RD Rotary Blade or Drag bit EX Tracked Hydraulic Excavator
HA Hand Auger RT Rotary Tri-cone bit HMLC Core – 63mm
*T TC-Bit HQ Core – 63mm
*V V-Bit NMLC Core – 47mm
NQ Core – 52mm
R Ripper
RH Rock Hammer
WATER
GROUNDWATER NOT The observation of groundwater, whether present or not, was not possible due to drilling water,
OBSERVED surface seepage or cave in of the borehole/test pit.
GROUNDWATER NOT The borehole/test pit was dry soon after excavation. However, groundwater could be present in
ENCOUNTERED less permeable strata. Inflow may have been observed had the borehole/test pit been left open
for a longer period.
SAMPLING AND TESTING
SPT Standard Penetration Test to AS1289.6.3.1-2004
5,4,10 N=14 5,4,10 = Blows per 150mm. N = Blows per 300mm penetration following 150mm seating
30/65mm Where practical refusal occurs, the blows and penetration for that interval are reported
RW Penetration occurred under the rod weight only
HW Penetration occurred under the hammer and rod weight only
HB Hammer double bouncing on anvil
DS Disturbed sample
BDS Bulk disturbed sample
SV Field shear vane test expressed as uncorrected shear strength (sv = peak value, sr = residual value)
PP Pocket penetrometer test expressed as instrument reading in kPa
U50 Thin walled tube sample - number indicates nominal sample diameter in millimetres
DCP Dynamic cone penetration test
CPT Electronic cone penetration test
CPTu Electronic cone penetration test with pore pressure (u) measurement
Rev1
February 2021
Page 29
METHOD OF SOIL DESCRIPTION
USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Soil is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
Particle Size Plasticity Properties
Major Sub Division Particle Size
Division
BOULDERS > 200 mm
COBBLES 63 to 200 mm
Coarse 19 to 63 mm
GRAVEL Medium 6.7 to 19 mm
Fine 2.36 to 6.7 mm
Coarse 0.6 to 2.36 mm
SAND Medium 0.21 to 0.6 mm
Fine 0.075 to 0.21
SILT 0.002 to 0.075
CLAY < 0.002 mm
NOTE: The U line is an approximate upper bound for most materials.
Data which plot above the U line may represent unusual/problem soil
behavior, or unreliable data and should be considered carefully.
MOISTURE CONDITION AS1726 - 2017
Symbol Term Description
D Dry Sands and gravels are free flowing. Clays & Silts may be brittle or friable and powdery.
M Moist Soils are darker than in the dry condition & may feel cool. Sands and gravels tend to cohere.
W Wet Soils exude free water. Sands and gravels tend to cohere.
CONSISTENCY AND DENSITY AS1726 - 2017
Symbol Term Undrained Shear Symbol Term Density Index % SPT “N” #
Strength
VS Very Soft 0 to 12 kPa VL Very Loose Less than 15 0 to 4
S Soft 12 to 25 kPa L Loose 15 to 35 4 to 10
F Firm 25 to 50 kPa MD Medium Dense 35 to 65 10 to 30
St Stiff 50 to 100 kPa D Dense 65 to 85 30 to 50
VSt Very Stiff 100 to 200 kPa VD Very Dense Above 85 Above 50
H Hard Above 200 kPa
In the absence of test results, consistency and density may be assessed from correlations with the observed behaviour of
the material.
# SPT correlations are not stated in AS1726 – 2017, and may be subject to corrections for overburden pressure and
equipment type.
Rev1
October 2017
Page 30
METHOD OF ROCK DESCRIPTION USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Rock is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
STRENGTH
Point Load
Symbol Term Index, Is(50) Field Guide
(MPa)
VL Very 0.03 to 0.1 Material crumbles under firm blows with sharp end of pick; can be peeled
Low with knife; too hard to cut a triaxial sample by hand. Pieces up to 30 mm
can be broken by finger pressure.
L Low 0.1 to 0.3 Easily scored with a knife; indentations 1 mm to 3 mm show in the specimen
with firm blows of pick point; has dull sound under hammer. A piece of core
150 mm long by 50 mm diameter may be broken by hand. Sharp edges of core
may be friable and break during handling.
M Medium 0.3 to 1 Readily scored with a knife; a piece of core 150 mm long by 50 mm diameter
can be broken by hand with difficulty.
H High 1 to 3 A piece of core 150 mm long by 50 mm diameter cannot be broken by hand but
can be broken with pick with a single firm blow; rock rings under hammer.
VH Very 3 to 10 Hand specimen breaks with pick after more than one blow; rock rings under
High hammer.
EH Extremely >10 Specimen requires many blows with geological pick to break through intact
High material; rock rings under hammer.
Relationship between Is(50) and UCS (unconfined compressive strength) will vary with rock type and strength, and
should be determined on a site-specific basis. UCS is typically 10 to 30 x Is(50), but can be as low as 5.
ROCK MATERIAL WEATHERING
Symbol Term Field Guide
Soil developed on extremely weathered rock; the mass structure and
Residual
RS substance fabric are no longer evident; there is a large change in volume
Soil but the soil has not been significantly transported.
Extremely Rock is weathered to such an extent that it has soil properties - i.e. it either
EW
Weathered disintegrates or can be remoulded, in water.
Whole of rock is discoloured, usually by iron staining or bleaching to the
extent that the colour of the original rock is not recognizable. Rock strength
Highly
HW is significantly changed by weathering. Porosity may be increased by
Weathered
leaching, or may be decreased due to deposition of weathering products in
Distinctly
DW pores.
Weathered
Whole of rock is discoloured, usually by iron staining or bleaching to the
Moderately extent that the colour of the original rock is not recognizable; but shows little
MW
Weathered or no change of strength from fresh rock.
Slightly Rock is slightly discoloured but shows little or no change of strength relative
SW
Weathered to fresh rock.
FR Fresh Rock shows no sign of decomposition or staining.
ABBREVIATIONS FOR DEFECT TYPES AND DESCRIPTIONS
Defect Type Coating or Infilling Roughness
CS/CZ Crushed seam/zone (Fault) Ca Calcite Po Polished
DB Drilling break Clay Clay Sm Smooth
EW Extremely weathered seam Cn Clean Sl Slickensided
HB Handling break Co Coating ( > 1mm) Ro Rough
IS/IZ Infilled seam/zone Fe Iron oxide VRo Very rough
Op Open
J Joint
Qz Quartz
Pt Parting St Stain Planarity
SS/SZ Sheared seam/zone (Fault) Vn Veneer (<1mm) Cu Curved
Vn Vein X Carbonaceous Dis Discontinuous
Ir Irregular
Pl Planar
St Stepped
Un Undulating
Rev4
February 2021
Page 31
PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
APPENDIX B
Laboratory Test Certificate
16 July 2021
Report No. 21236-001-Rev0
Page 32
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Material Test Report
MA WorRRISON
GEOTECHNIC
Report Number: ML21/160-1 .
Issue Number: 1 Brisbane | Gold Coast | Sunshine Coast
. Morrison Geotechnic Pty Ltd
Date Issued: 12/07/2021 ABN: 51 009 878 899
Client: TECTONIC GEOTECHNICAL PTY LTD Maroochydore Laboratory
PO BOX 899, BUDERIM QLD Unit 4 / 81 Wises Road Maroochydore QLD 4558
Contact: Michael Cocks Phone: (07) 5443 9522
Project Number:
Project Name:
ML21/160
Geotechnical Investigation - 21 Maher Tce
Email: [email protected]
Accredited for compliance with ISO/IEC 17025 - Testing
Project Location: 21 Maher Terrace, Sunshine Beach Quo
Client Reference: 21236 NATA J
Work Request: 3917 \
Sample Number: M21-3917A Approved Signatory: Gina Flett
Date Sampled: 22/06/2021 ACCREDITATION Lab Manager
Dates Tested:
Sampling Method:
Site Selection:
Sample Location:
02/07/2021 - 06/07/2021
Sampled by Client
The results apply to the sample as received
Selected by Client
BH2, Depth: 1.2 - 1.5m
NATA Accredited Laboratory Number: 1169
Particle Size Distribution
TT
Sieve Passed % |Passing Retained % |Retained | Sand Gravel, Cobbles
Limits Limits ieved 4 2 ee
6.7 mm 100 0 10d mm Ses 3 8 48
4.75 mm 100 0
2.36 mm 100 0 99) A
1.18 mm 99 0 804
0.6 mm 99 1 2
0.425 mm 98 1 gry
0.3 mm 96 2 2 60}
0.15 mm 85 “1 8 aa
0.075 mm 68 16 é
40}
Sample Hi Oven Dried 30}
Pre| ion Method Dry Sieve 201
Passing 0.425 (% 98
Liquid Limit (% 47 10)
Plastic Limit (% 25
Plasticity Index 041 02 41 2348 10 2030 100 20
Weighted Pla Index (% Particle Size (mm)
Linear Shrinkage (AS1289 3.4.1) Min Max
Moisture Condition Determined By | AS 1289.3.1.1/ AS
1289.3.1.2/ AS
1289.3.9.1/ AS
1289.3.9.2
Linear Shrinkage (%) 75
Cracking Crumbling Curling None
Report Number: ML21/160-1
This document shall not be reproduced except in full without approval of the laboratory.
Results relate only to the ems tested/ sampled.
Page 1 of 1
Page 33
PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
APPENDIX C
AGS Guidelines - Qualitative Terminology for Use in
Assessing Risk to Property
Some Guidelines for Hillside Construction
16 July 2021
Report No. 21236-001-Rev0
Page 34
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX C: LANDSLIDE RISK ASSESSMENT
QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY
QUALITATIVE MEASURES OF LIKELIHOOD
Approximate Annual Probability
Implied Indicative Landslide
Description Descriptor Level
Indicative Notional Recurrence Interval
Value Boundary
10-1 5x10-2
10 years The event is expected to occur over the design life. ALMOST CERTAIN A
20 years The event will probably occur under adverse conditions over the
-2
10 100 years
design life.
LIKELY B
-3
-3 5x10 200 years
10 1000 years The event could occur under adverse conditions over the design life. POSSIBLE C
5x10-4 2000 years
The event might occur under very adverse circumstances over the
10-4 10,000 years
design life.
UNLIKELY D
-5 5x10-5 20,000 years
10 The event is conceivable but only under exceptional circumstances
100,000 years RARE E
over the design life.
-6 5x10-6 200,000 years
10 1,000,000 years The event is inconceivable or fanciful over the design life. BARELY CREDIBLE F
Note: (1) The table should be used from left to right; use Approximate Annual Probability or Description to assign Descriptor, not vice versa.
QUALITATIVE MEASURES OF CONSEQUENCES TO PROPERTY
Approximate Cost of Damage
Description Descriptor Level
Indicative Notional
Value Boundary
Structure(s) completely destroyed and/or large scale damage requiring major engineering works for
200% CATASTROPHIC 1
stabilisation. Could cause at least one adjacent property major consequence damage.
100%
Extensive damage to most of structure, and/or extending beyond site boundaries requiring significant
60% MAJOR 2
stabilisation works. Could cause at least one adjacent property medium consequence damage.
40%
Moderate damage to some of structure, and/or significant part of site requiring large stabilisation works.
20% MEDIUM 3
Could cause at least one adjacent property minor consequence damage.
10%
5% 1% Limited damage to part of structure, and/or part of site requiring some reinstatement stabilisation works. MINOR 4
Little damage. (Note for high probability event (Almost Certain), this category may be subdivided at a
0.5% INSIGNIFICANT 5
notional boundary of 0.1%. See Risk Matrix.)
Notes: (2) The Approximate Cost of Damage is expressed as a percentage of market value, being the cost of the improved value of the unaffected property which includes the land plus the
unaffected structures.
(3) The Approximate Cost is to be an estimate of the direct cost of the damage, such as the cost of reinstatement of the damaged portion of the property (land plus structures), stabilisation
works required to render the site to tolerable risk level for the landslide which has occurred and professional design fees, and consequential costs such as legal fees, temporary
accommodation. It does not include additional stabilisation works to address other landslides which may affect the property.
(4) The table should be used from left to right; use Approximate Cost of Damage or Description to assign Descriptor, not vice versa
Australian Geomechanics Vol 42 No 1 March 2007
Form No. 68039
68039 RL2Risk
Landslide August 2010
Management Issued 10/7/07
Page 35
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX C: – QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY (CONTINUED)
QUALITATIVE RISK ANALYSIS MATRIX – LEVEL OF RISK TO PROPERTY
LIKELIHOOD CONSEQUENCES TO PROPERTY (With Indicative Approximate Cost of Damage)
Indicative Value of 1: CATASTROPHIC 2: MAJOR 3: MEDIUM 4: MINOR 5:
Approximate Annual 200% 60% 20% 5% INSIGNIFICANT
Probability 0.5%
A – ALMOST CERTAIN 10-1 VH VH VH H M or L (5)
-2
B - LIKELY 10 VH VH H M L
C - POSSIBLE 10-3 VH H M M VL
D - UNLIKELY 10-4 H M L L VL
-5
E - RARE 10 M L L VL VL
-6
F - BARELY CREDIBLE 10 L VL VL VL VL
Notes: (5) For Cell A5, may be subdivided such that a consequence of less than 0.1% is Low Risk.
(6) When considering a risk assessment it must be clearly stated whether it is for existing conditions or with risk control measures which may not be implemented at the current
time.
RISK LEVEL IMPLICATIONS
Risk Level Example Implications (7)
Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of treatment
VH VERY HIGH RISK options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost more than value of the
property.
Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options required to reduce
H HIGH RISK
risk to Low. Work would cost a substantial sum in relation to the value of the property.
May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and
M MODERATE RISK implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be
implemented as soon as practicable.
Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is
L LOW RISK
required.
Acceptable. Manage by normal slope maintenance procedures.
VL VERY LOW RISK
Note: (7) The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of the property at risk; these are only
given as a general guide.
Australian Geomechanics Vol 42 No 1 March 2007
Form No. Landslide
68039 68039 RL2Risk
August 2010
Management Issued 10/7/07
Page 36
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX G - SOME GUIDELINES FOR HILLSIDE CONSTRUCTION
GOOD ENGINEERING PRACTICE POOR ENGINEERING PRACTICE
ADVICE
GEOTECHNICAL Obtain advice from a qualified, experienced geotechnical practitioner at early Prepare detailed plan and start site works before
ASSESSMENT stage of planning and before site works. geotechnical advice.
PLANNING
SITE PLANNING Having obtained geotechnical advice, plan the development with the risk Plan development without regard for the Risk.
arising from the identified hazards and consequences in mind.
DESIGN AND CONSTRUCTION
Use flexible structures which incorporate properly designed brickwork, timber Floor plans which require extensive cutting and
or steel frames, timber or panel cladding. filling.
HOUSE DESIGN
Consider use of split levels. Movement intolerant structures.
Use decks for recreational areas where appropriate.
SITE CLEARING Retain natural vegetation wherever practicable. Indiscriminately clear the site.
ACCESS & Satisfy requirements below for cuts, fills, retaining walls and drainage. Excavate and fill for site access before
DRIVEWAYS Council specifications for grades may need to be modified. geotechnical advice.
Driveways and parking areas may need to be fully supported on piers.
EARTHWORKS Retain natural contours wherever possible. Indiscriminatory bulk earthworks.
Minimise depth. Large scale cuts and benching.
CUTS Support with engineered retaining walls or batter to appropriate slope. Unsupported cuts.
Provide drainage measures and erosion control. Ignore drainage requirements
Minimise height. Loose or poorly compacted fill, which if it fails,
Strip vegetation and topsoil and key into natural slopes prior to filling. may flow a considerable distance including
Use clean fill materials and compact to engineering standards. onto property below.
FILLS Batter to appropriate slope or support with engineered retaining wall. Block natural drainage lines.
Provide surface drainage and appropriate subsurface drainage. Fill over existing vegetation and topsoil.
Include stumps, trees, vegetation, topsoil,
boulders, building rubble etc in fill.
ROCK OUTCROPS Remove or stabilise boulders which may have unacceptable risk. Disturb or undercut detached blocks or
& BOULDERS Support rock faces where necessary. boulders.
Engineer design to resist applied soil and water forces. Construct a structurally inadequate wall such as
Found on rock where practicable. sandstone flagging, brick or unreinforced
RETAINING
Provide subsurface drainage within wall backfill and surface drainage on slope blockwork.
WALLS
above. Lack of subsurface drains and weepholes.
Construct wall as soon as possible after cut/fill operation.
Found within rock where practicable. Found on topsoil, loose fill, detached boulders
Use rows of piers or strip footings oriented up and down slope. or undercut cliffs.
FOOTINGS
Design for lateral creep pressures if necessary.
Backfill footing excavations to exclude ingress of surface water.
Engineer designed.
Support on piers to rock where practicable.
SWIMMING POOLS Provide with under-drainage and gravity drain outlet where practicable.
Design for high soil pressures which may develop on uphill side whilst there
may be little or no lateral support on downhill side.
DRAINAGE
Provide at tops of cut and fill slopes. Discharge at top of fills and cuts.
Discharge to street drainage or natural water courses. Allow water to pond on bench areas.
SURFACE Provide general falls to prevent blockage by siltation and incorporate silt traps.
Line to minimise infiltration and make flexible where possible.
Special structures to dissipate energy at changes of slope and/or direction.
Provide filter around subsurface drain. Discharge roof runoff into absorption trenches.
Provide drain behind retaining walls.
SUBSURFACE
Use flexible pipelines with access for maintenance.
Prevent inflow of surface water.
Usually requires pump-out or mains sewer systems; absorption trenches may Discharge sullage directly onto and into slopes.
SEPTIC &
be possible in some areas if risk is acceptable. Use absorption trenches without consideration
SULLAGE
Storage tanks should be water-tight and adequately founded. of landslide risk.
EROSION Control erosion as this may lead to instability. Failure to observe earthworks and drainage
CONTROL & Revegetate cleared area. recommendations when landscaping.
LANDSCAPING
DRAWINGS AND SITE VISITS DURING CONSTRUCTION
DRAWINGS Building Application drawings should be viewed by geotechnical consultant
SITE VISITS Site Visits by consultant may be appropriate during construction/
INSPECTION AND MAINTENANCE BY OWNER
OWNER’S Clean drainage systems; repair broken joints in drains and leaks in supply
RESPONSIBILITY pipes.
Where structural distress is evident see advice.
If seepage observed, determine causes or seek advice on consequences.
Australian Geomechanics Vol 42 No 1 March 2007 113
Form No. 68029 RL2 August 2010
Page 37
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
114 Australian Geomechanics Vol 42 No 1 March 2007
Form No. 68029 RL2 August 2010
Page 38
PROPOSED RESIDENCE
21 MAHER TERRACE, SUNSHINE BEACH
APPENDIX D
Limitations
16 July 2021
Report No. 21236-001-Rev0
Page 39
LIMITATIONS This document has been prepared for the purpose outlined in Tectonic’s proposal and no responsibility is accepted for the use of this document, in whole or in part, for any other purpose. The scope of Tectonic’s Services are as described in Tectonic’s proposal, and are subject to restrictions and limitations. Tectonic did not perform a complete assessment of all possible conditions or circumstances that may exist at the site referenced in the report. If a service is not expressly indicated, do not assume it has been provided. If a matter is not addressed, do not assume that any determination has been made by Tectonic in regards to it. Conditions may exist which were undetectable given that economic and time constraints limit the practical extent of geotechnical investigation. Variations in conditions may occur between investigation locations, and there may be special conditions pertaining to the site which have not been revealed by the investigation and which have not therefore been taken into account in the document. Where variations exist on site, additional studies and actions may be required. Tectonic’s opinions are based upon information that existed at the time that the work was performed. The passage of time, man-made or natural events, may alter the site conditions. It is understood that the Services undertaken allowed Tectonic to form an opinion of the actual conditions of the site at the time the site was visited and cannot be used to assess the effect of any subsequent changes in the quality of the site, or its surroundings, or any laws or regulations. Any assessments made in the preparation of this document are based on the conditions indicated from published sources and the findings of the investigation described. Actual subsurface conditions may differ from those indicated in the document (e.g. between boreholes or test pits). No warranty is included, either express or implied, that the actual conditions will conform exactly to the assessments contained in this document. Where data supplied by the client or other external sources, including previous site investigation data, have been used, it has been assumed that the information is correct unless otherwise stated. No responsibility is accepted by Tectonic for incomplete or inaccurate data supplied by others. This document is provided for the sole use by the Client and its professional advisers. No responsibility whatsoever for the contents of this document will be accepted to any person other than the Client. Any use which a third party makes of this document, or any reliance on or decisions to be made based on it, is the responsibility of such third parties. Tectonic accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this document. Rev 1 (March 2016)
Used in these records
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20220109 - 21 Maher Tce, Sunshine Beach - Construction of Detached Dwelling and Swimming P - 21236-001-Geotech 21 Maher Tce.pdfRelated documentApplication case desk ↗
20220109 - 21 Maher Tce, Sunshine Beach - Construction of Detached Dwelling and Swimming Pool - Geotech.pdfRelated documentApplication case desk ↗
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