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Appendix E - Geotechnical Report
Attached to the e-mail Applicant advises of Referral - RAL19/0008.
GEOTECHNICAL INVESTIGATION Proposed Reconfiguration of a Lot 216 Black Mountain Road Black Mountain Report for Murray and Michelle Richardson Report 18127-001-Rev0 19 June 2018 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 RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
Document Review
Document No. Revision Prepared By Reviewed By Date Issued
001 0 Robert Gibb Ashley Davey 19 June 2018
Report Distribution
Document Revision Method of Delivery Issued To
Murray & Michelle Richardson
001 0 Electronic
([email protected])
Callan Lowrie (Murray & Associates)
001 0 Electronic
([email protected])
Prepared By: Reviewed By:
Robert Gibb BSc (Hons) Ashley Davey RPEQ 8159
Engineering Geologist Principal Geotechnical Engineer
19 June 2018
Report No. 18127-001-Rev0 i
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
Executive Summary
This report details the results of a geotechnical investigation undertaken for a proposed reconfiguration of a
lot at 216 Black Mountain Road, Black Mountain. The investigation was performed by Tectonic Geotechnical
Pty Ltd for Murray and Michelle Richardson. Murray & Associates are consulting planners for the project.
The investigation comprised digging of test pits at five locations, together with in situ strength testing, and
geotechnical laboratory analyses. This report summarises the results of the investigation and provides
geotechnical recommendations regarding the design of earthworks, footings, site classification, retaining
walls. A quantitative and qualitative slope stability assessment is included. An assessment of positioning for
on-site effluent disposal has also been undertaken.
The proposed reconfiguration will comprise dividing the existing allotment into two separate lots. The
northern lot (Lot 1) will retain the existing house and be of 3.333 ha; whilst the southern lot (Lot 2) will be of
1.366 ha, with a new residence to be constructed on site. A building envelope has been nominated to the
south of Lot 2, and it is understood access will be gained directly off Black Mountain Road via the existing
allotment driveway.
Test pits generally encountered similar subsurface profiles, comprising a surficial covering of topsoil to
around 0.2 m below ground level (BGL), underlain by residual very stiff silty clay to between 1 m and 1.7 m
BGL, then extremely weathered material comprising stiff to very stiff silty clay with cobbles to between 2 m
and 2.7 m BGL, underlain by weathered phyllite rock. It was possible to dig in to the rock for around 0.4 m to
0.7 m before bucket refusal (6 tonne machine) was encountered. Groundwater seepage was not
encountered in any of the test pits at the time of investigation, with soils being dry to moist.
Cut and fill proposals are not known, however, based on the nominated building envelope and the typical
size of a house on a site of this size, depth/height of cut/fill of 1 m has been allowed for, or should otherwise
be supported by an engineer designed retaining wall.
Following clearing and topsoil stripping (estimated at about 0.2 m depth), the exposed subgrade materials
are expected to comprise mostly stiff to very stiff silty clays. The residual and extremely weathered clay
materials found on site may be suitable for re-use as structural fill, subject to appropriate moisture
conditioning.
Footing design may be based upon a site classification equivalent to Class M according to AS2870:2011,
with estimated characteristic surface movements (‘ys’) of 20 mm to 40 mm. Final site classification and
footing design will be dependent on the type of fill material placed and degree of fill placement supervision.
Footings shall be founded in weathered phyllite and may be designed with an allowable bearing capacity of
350 kPa.
Based upon the existing site conditions, and subject to the implementation of recommendations given within
this report, it is our assessment that there would be a Low (L) Risk of global slope instability affecting the
proposed subdivision. This is with a minimum factor of safety against slope instability of 1.5. The extent of
site works, including cut/fill, must be limited to maintain slope stability. Control of stormwater flows via
channels and/or pipes will also be essential to maintain slope stability.
It has been assessed from the results of the investigation that the soil profiles across the likely effluent
disposal area on proposed Lot 2 is equivalent to a Strongly Structured Medium to Heavy Clay (Soil
Category 6). It is recommended that on-site treatment and land application for Lot 2 should comprise a
household sewage treatment plant connected to a surface or shallow subsurface irrigation area of 322 m².
Final irrigation areas and detailed wastewater system design will be dependent upon individual site
assessments at the building stage. There is sufficient room on each lot for these areas, allowing for
setback considerations.
19 June 2018
Report No. 18127-001-Rev0 ii
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
Table of Contents
1.0 INTRODUCTION ........................................................................................................................................................ 1
2.0 PROPOSED DEVELOPMENT ................................................................................................................................... 1
3.0 SITE DESCRIPTION .................................................................................................................................................. 2
4.0 METHOD OF INVESTIGATION ................................................................................................................................. 4
4.1 Fieldwork ...................................................................................................................................................... 4
4.2 Laboratory Testing ........................................................................................................................................ 4
5.0 INVESTIGATION FINDINGS ..................................................................................................................................... 5
5.1 Geology ........................................................................................................................................................ 5
5.2 Subsurface Conditions.................................................................................................................................. 5
5.3 Laboratory Testing ........................................................................................................................................ 6
6.0 SLOPE STABILITY ASSESSMENT .......................................................................................................................... 6
6.1.1 Existing Conditions.................................................................................................................................. 6
6.1.2 Qualitative Stability Assessment ............................................................................................................. 7
6.1.3 Quantitative Stability Assessment ........................................................................................................... 8
7.0 ENGINEERING ASSESSMENT ................................................................................................................................ 9
7.1 Earthworks .................................................................................................................................................... 9
7.1.1 Site Preparation and Trafficability ........................................................................................................... 9
7.1.2 Excavations ............................................................................................................................................. 9
7.1.3 Batter Slopes .......................................................................................................................................... 9
7.1.4 Filling..................................................................................................................................................... 10
7.1.5 Material Suitability for Re-Use ............................................................................................................... 10
7.2 Building Foundations .................................................................................................................................. 10
7.2.1 Site Classification .................................................................................................................................. 10
7.2.2 Footing Design ...................................................................................................................................... 10
7.3 Retaining Structures ................................................................................................................................... 11
7.4 Pavement Design Parameters .................................................................................................................... 11
7.5 Drainage ..................................................................................................................................................... 12
8.0 WASTEWATER TREATMENT AND DISPOSAL .................................................................................................... 12
8.1 Wastewater Flow Design Allowance ........................................................................................................... 12
8.2 Terrain-Soil Assessment............................................................................................................................. 12
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PROPOSED RECONFIGURATION OF A LOT
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8.3 Recommendations ...................................................................................................................................... 12
8.3.1 System Type ......................................................................................................................................... 12
8.3.2 System Positioning................................................................................................................................ 13
8.3.3 System Construction ............................................................................................................................. 13
8.3.4 Maintenance and Inspection ................................................................................................................. 14
9.0 LIMITATIONS .......................................................................................................................................................... 14
TABLES
Table 1: Summary of Shrink Swell Index Results ................................................................................................................ 6
Table 2: Stability Risk Levels .............................................................................................................................................. 7
Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007) ......................................................................... 7
Table 4: Retaining Structure Design Parameters .............................................................................................................. 11
Table 5: Horizontal and Vertical Setback/Separation Distances for Irrigation Areas ......................................................... 13
TEXT FIGURES
Text Figure 1: Extract of Plan of Development (courtesy Murray) ....................................................................................... 1
Text Figure 2: Site location and surrounds (courtesy of NC Interactive Maps, 2016).......................................................... 2
Text Figure 3: Proposed building area looking south-east (excavator at proposed new access for Lot 1) .......................... 3
Text Figure 4: Looking downslope towards gully at base of building area on proposed Lot 2 ............................................ 3
Text Figure 5: View looking east to Black Mtn Rd; and down to connection point for proposed driveway .......................... 3
Text Figure 6: Extract from Gympie Geology Map ............................................................................................................. 5
Text Figure 7: Extract from NC Landslide Hazard Mapping ................................................................................................ 6
Text Figure 8: Extract from SlopeW Modelling ................................................................................................................... 8
Text Figure 9: Footing depth required to minimise risk of undermining ............................................................................ 11
FIGURES
Figure 1: Site Plan
APPENDICES
APPENDIX A
Test Pit Reports and Explanatory Notes
APPENDIX B
Laboratory Test Certificate
APPENDIX C
AGS 2007 Practice Note Guidelines for Landslide Risk Management
Qualitative Terminology for Use in Assessing Risk to Property
APPENDIX D
Limitations
19 June 2018
Report No. 18127-001-Rev0 iv
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
1.0 INTRODUCTION
This report details the results of a geotechnical investigation undertaken for the proposed reconfiguration of
a lot at 216 Black Mountain Road, Black Mountain. The investigation was performed by Tectonic
Geotechnical Pty Ltd (Tectonic) for Murray and Michelle Richardson in accordance with Proposal P18150-
Rev0 dated 18 April 2018. Murray & Associates (Murray) are consulting planners for the project.
The investigation comprised digging of test pits at four locations, together with in situ strength testing, and
geotechnical laboratory analyses. This report summarises the results of the investigation and provides
geotechnical recommendations regarding the design of earthworks, footings, site classification, and retaining
walls. A qualitative and quantitative slope stability assessment is included. An assessment of positioning for
on-site effluent disposal has also been undertaken.
2.0 PROPOSED DEVELOPMENT
A Plan of Development, prepared by Murray (Ref. Dwg No. 61500, dated 5 April 2018) indicates that the
proposed reconfiguration will comprise dividing the existing allotment from one lot into two separate lots. The
northern lot (Lot 1) will retain the existing house and be of 3.333 ha; with the southen lot (Lot 2) being of
1.366 ha, where a new residence is to be constructed. A building envelope has been nominated at the
southern boundary of proposed Lot 2. The proposed access for Lot 2 was indicated by the client on site to
be along part of the existing access. A new access is to be created for Lot 1 off Black Mountain Road (Ref.
Text Figure 1).
Contour information (Noosa Council [NC], incorporated in to the Murray plan of development) indicates a fall
of around 10 m from south to north across the nominated building envelope. Cut/fill earthworks will likely be
required to provide a level building platform, however the extent and depth/height of such works would
depend on the type, position and size of residence proposed.
No further details regarding construction were provided.
Possible route for new access to Lot 1
Proposed building envelope
Text Figure 1: Extract of Plan of Development (courtesy Murray)
19 June 2018
Report No. 17427-001-Rev0 1
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
3.0 SITE DESCRIPTION
The existing allotment is described as Lot 9 on RP131369, with a total area of 4.7 ha, having frontage to
Black Mountain Road to the south. Surrounding the site are large rural acreage properties, with a mixture of
grazing and bushland. An overview of the site and surrounds is given below in Text Figure 2.
Site boundary
Gullies Existing house on ridge
on proposed Lot 1
Proposed building
area
Access to existing house
Text Figure 2: Site location and surrounds (courtesy of NC Interactive Maps, 2016)
The topography of the overall allotment consists of two gullies to the north and south, orientated south-west
to north-east, separated by a central ridge. Black Mountain Road along the southern boundary, and the
central ridge, are situated at around RL 190 m AHD, with the bases of the gullies being around RL 150 m to
RL 160 m AHD.
Ground slopes recorded using a hand-held inclinometer were taken during the site walk-over, and indicate a
relatively consistent slope of 15° (27 %) is present across much of the proposed building envelope. The site
slopes down to the north, and short steep slopes of up to 35° (70 %) are present forming the creek sides at
the base of the gully. The route of the proposed new driveway access for Lot 1 is formed on a cut/fill bench
sidelong with the natural slope. The batter face of this was inclined at around 30° (58 %), with ground of
around 15° (27 %) below to the north. Recorded ground slopes are shown in Figure 1, attached at the end of
the report text.
Between Black Mountain Road and the southern boundary of the proposed building envelope, medium sized
mature trees were present, and the immediate slopes adjacent to the creek gully to the north were also
relatively densely vegetated. Vegetation around the proposed building envelope generally consisted of a
maintained grassed slope.
Overhead electricity wires were noted to run along the north-eastern boundary of the proposed building
envelope, as shown in Text Figure 1, denoted by an easement.
Site conditions at the time of investigation are shown in Text Figures 3 to 5 on the following page.
19 June 2018
Report No. 17427-001-Rev0 2
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
Text Figure 3: Proposed building area looking south-east (excavator at proposed new access for Lot 1)
Text Figure 4: Looking downslope towards gully at base of building area on proposed Lot 2
Text Figure 5: View looking east to Black Mtn Rd; and down to connection point for proposed driveway
19 June 2018
Report No. 17427-001-Rev0 3
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
4.0 METHOD OF INVESTIGATION
4.1 Fieldwork
Four test pits (designated TP1 to TP4) were excavated within the nominated building envelop, and one test
pit (designated TP5) was dug around the position of the proposed driveway. Test pits were dug using a
small, 6 tonne tracked excavator.
Test pits reached depths of 2.3 m and 3.0 m below ground level (BGL) and were generally terminated at
bucket refusal (based on a 6 tonne excavator). In situ soil strength was assessed using a pocket
penetrometer (PP) in test pit sidewalls and in recovered spoil. Borehole locations are shown in Figure 1.
The fieldwork was undertaken in the presence of an experienced engineering geologist from Tectonic on
17 May 2018. The engineering geologist was responsible for logging soil and rock profiles in accordance
with AS1726 Geotechnical site investigations, making groundwater observations. Undisturbed U63 tubes in
clay, and disturbed soil samples, were collected for subsequent laboratory testing. Boreholes were
backfilled with spoil on completion, with excess spoil mounded at the surface.
Borehole reports are attached in Appendix A, together with explanatory notes.
4.2 Laboratory Testing
An undisturbed U63 tube sample was dispatched to Coffey Services Australia Pty Ltd, a NATA accredited
geotechnical laboratory located in Brisbane, for geotechnical testing. Laboratory testing was undertaken in
accordance with Australian Standard AS1289 Method for Testing Soils for Engineering Purposes and
comprised analysis for Shrink Swell Index.
Refer to Section 5.3 for a summary of results.
19 June 2018
Report No. 17427-001-Rev0 4
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PROPOSED RECONFIGURATION OF A LOT
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5.0 INVESTIGATION FINDINGS
5.1 Geology
The 1:100,000 scale Gympie Special Geological Map (Sheet 9445 and Part 9545, DME 1999) indicates that
the site is underlain by strata of the early to middle Triassic age Kin Kin Beds (grey shading) comprising
“arenite, argillite, phyllite”. An extract from the geological map is shown in Text Figure 6 below.
Approximate site location
Text Figure 6: Extract from Gympie geology map
5.2 Subsurface Conditions
Detailed descriptions of the subsurface conditions encountered in the test pits are provided in the test pit
reports attached in Appendix A, along with definition sheets which describe terms and abbreviations used
on the reports.
Test pits generally encountered similar subsurface profiles which can be summarised as follows:
Topsoil comprising stiff silty clay to depths of 0.1 m to 0.2 m BGL; underlain by
Residual material comprising mostly very stiff, medium to high plasticity silty clay, occasionally
with gravel to depths of between 1 m and 1.7 m BGL; underlain by
Extremely weathered material comprising stiff to very stiff, high plasticity, silty clay with gravel
and cobbles to depths of between 2 m and 2.7 m BGL; underlain by
Highly weathered to moderately weathered, very low strength, pale grey phyllite, with a thinly
laminated fabric; typically excavatable to a depth of about 0.4 m to 0.7 m, before bucket refusal
was encountered.
No fissured clays were encountered in the test pits. Low strength phyllite rock was also observed in the
cutting on the southern side of Black Mountain Road, opposite the allotment entrance.
Fill was not encountered in the test pits, but may be expected on the sidelong batter formed along the
proposed alignment of the new driveway for Lot 1.
Groundwater seepage was not encountered in any of the test pits at the time of investigation, with soils
being dry to moist. However, it should be noted that groundwater seepage may develop at shallow depths
within permeable horizons or at soil/rock interfaces, particularly following periods of heavy or prolonged
rainfall.
19 June 2018
Report No. 17427-001-Rev0 5
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
5.3 Laboratory Testing
Table 1 below summarises the results of geotechnical laboratory testing, comprising shrink swell testing on
an undisturbed U63 tube, from the residual clay within the proposed building envelope. Results supplied by
the laboratory are given below in Table 1. The laboratory certificate, with full testing results, is presented in
Appendix B.
Table 1: Summary of Shrink Swell Index Results
TP No. Depth (m) Shrink Swell Index (Iss %)
TP4 0.15-0.55 1.2
6.0 SLOPE STABILITY ASSESSMENT
6.1.1 Existing Conditions
NC mapping (refer Text Figure 7 below) indicates that the majority of the site is within the “Landslide Hazard
Area,” denoted by pink shading.
Site boundary
Text Figure 7: Extract from NC Landslide Hazard Mapping
It should be noted that the NC mapping is a broad-scale indication of the potential landslide susceptibility
only and is superseded by site specific investigation and analysis works. At the time of our visit, the site
did not exhibit any indicators of significant slope instability. No landslide back scarps, groundwater
“springs,” or areas of naturally ‘hummocky’ ground were observed. The slope below the nominated
building envelope on proposed Lot 1 was noted to be consistent in nature, and mostly linear/planar.
Trees with bent/tilting trunks were observed only in the densely vegetated parts of the gully, and at the
crest of the road fill embankment along the southern boundary. This can be, but not necessarily, a sign of
slope instability.
It is inferred that the inclusion of the site within the “Landslide Hazard Area” is due to the ground slopes
exceeding 15 % (8° to 9°), which in themselves, do not always present a slope instability issue.
19 June 2018
Report No. 17427-001-Rev0 6
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
6.1.2 Qualitative 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 below, and
the Qualitative Terminology for Use in Assessing Risk to Property is 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
L Low Risk
to 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, and subject to the implementation of recommendations given below,
it is our opinion that there is a Low (L) Risk of global slope instability affecting the proposed subdivision.
Regulators (NC) normally require that a Very Low or Low Risk of landslide affecting property must be
demonstrated to enable development approval. Summarised in Table 3 below is our qualitative assessment
of landslide risk for the site. A summary of qualitative terminology for use in assessing risk to property is
attached (taken from AGS 2007) in Appendix C.
Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007)
Assessed
Hazard Likelihood Consequence
Risk
Comments
The likelihood of a relatively shallow failure through
the stiff (or stiffer) residual soils is assessed as Rare
due to the gentle to moderate ground slopes (in the
1: Shallow landslide in stiff (or
vicinity of the proposed building envelope), strength
stiffer) residual/extremely
Rare Medium Low of these materials, apparent lack of groundwater,
weathered soil materials above
and anticipated scope of future earthworks for
the foundation depth
residential construction. A potential Medium impact
from such instability is assessed, with the resultant
risk to be Low as per AGS 2007.
The likelihood of a deep failure through the very low
strength (or stronger) phyllite is assessed as Barely
Credible due to the lack of evidence of such
2: Deep seated landslide
Barely instability on the site, and through the surrounding
through the weathered phyllite Major Very Low
Credible area, combined with the strength of the material
rock below the foundation depth
encountered. A potential Major impact from such
instability is assessed, with the resultant risk to be
Very Low as per AGS 2007.
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PROPOSED RECONFIGURATION OF A LOT
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6.1.3 Quantitative Stability Assessment
In order to calculate the factor of safety (FOS) against slope instability for a residence situated within the
nominated building envelope on proposed Lot 2, numerical analysis has been conducted using the Slope/W
computer program adopting subsurface conditions based on the site investigation. The subsurface profile
described in Section 5.2 has been used in the analysis, together with the ground surface profile from the
slope crest down to the bed of the gully across the proposed building envelope.
Results of the numerical slope stability analysis are provided below.
1.5
Name: EW Materi al
Unit Weight: 18 kN/m ³
Cohesion': 4 kPa
Phi': 25 °
20 kPa surcharge to represent house/fil l pad
Name: Residual Soil
Unit Weight: 19 kN/m ³
Cohesion': 5 kPa Name: Weathered Phyl li te Rock
Phi': 27 ° Unit Weight: 27 kN/m ³
Cohesion': 15 kPa
Phi': 32 °
Text Figure 8: Extract from SlopeW Modelling
The key points from our analysis are summarised as follows:
Unit weight and shear strength parameters adopted for the soil and weathered rock strata were
taken mainly from the lower to mid-range of values recommended for similar materials in Appendix D
of Australian Standard AS4678-2002 ‘Earth Retaining Structures’.
Analysis was undertaken for specified slip entry and exit zones, with minimum FOS values of 1.5
being recorded, assuming the groundwater table is situated at the soil/rock interface (it should be
noted that groundwater was not encountered in the test pits), and a 20 kPa surcharge area (to
represent up to 1 m of fill).
This therefore, satisfies the requirement for hillside developments in the NC criteria for construction on steep
land, and the general industry minimum FOS.
Our analysis indicates that the proposed development will achieve at least the required minimum FOS.
Subject to implementation of the recommendations made in Section 7 during development works, there will
be a Low Risk of slope instability affecting the proposed development.
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PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
7.0 ENGINEERING ASSESSMENT
7.1 Earthworks
Preparatory cut and fill activities have not been indicated by Murray or the client in advance of the
geotechnical investigation. However, based on the building envelope given, and the assumed likely building
position being towards the south (upslope side) of the envelope, cut/fill depths/heights in the order of 1 m
would be permitted from a slope stability point of view. Should future cut/fill exceed this, the
recommendations contained in this report must be reviewed by Tectonic.
7.1.1 Site Preparation and Trafficability
Organic rich topsoil and any uncontrolled fill (e.g. over the proposed driveway alignment) should be stripped
from future construction and filling areas and be set aside. Based on the test pit results stripping depths
across the proposed building envelope to remove organic rich topsoil should be in the order of 0.2 m BGL
however, deeper pockets of topsoil may be present across the site. Organic rich topsoils must not be re-
used as structural fill, however may be retained on site for later use across landscaping areas, if required.
Following clearing and topsoil stripping, the exposed subgrade materials are expected to comprise mostly
stiff (or stiffer), high plasticity, silty clays. Residual and extremely weathered clay materials, such as those
found on site, are subject to strength loss from repetitive vehicle loading, particularly from rubber tyred plant,
or if they become wet. Due to the potential for poor trafficability during and after wet periods, placement of a
minimum 150 mm thick granular working platform may be required, particularly across laydown areas and
site access tracks.
The stripped subgrade in proposed fill areas should be inspected by an experienced engineer prior to
placement of fill. All subgrade areas should be proof rolled by a minimum 4 tonne roller to identify any
soft/loose material. Any soft/loose material should be over-excavated to expose a stiff (or stiffer) foundation
and then backfilled with compacted select material as recommended in Section 7.1.4.
The site should be graded to shed surface water runoff away from proposed building envelopes. Swale
drains should be constructed along the toes of any cuts, and along the upslope extents of construction areas
to intercept runoff from upslope. The drains should be graded to discharge collected waters to a control
point before being released to a suitable area on-site e.g. natural gullies/drainage lines away from the
construction area.
Appropriate erosion and sediment control measures must be installed prior to commencement of earthworks.
7.1.2 Excavations
Excavations could extend to depths of up to 1 m for earthworks cut activities, and possibly deeper subject to
construction requirements. Subsurface conditions are anticipated to be within the excavation limits of small
to medium sized excavators with toothed buckets (i.e. 6 tonne to 12 tonne). Should excavations extend more
than 0.5 m in to the phyllite bedrock, ripping or pneumatic breaking attachments, together with larger
equipment, may be required.
7.1.3 Batter Slopes
Temporary cuts in the natural stiff (or stiffer) silty clay should be formed no steeper than 1V:1H. Flatter
temporary batters may be required if groundwater seepage is encountered, or if earthworks are undertaken
during a period of heavy rainfall. Permanent cuts in natural stiff (or stiffer) materials and controlled fill batters
may be formed at 1V:2H. Cuts in weathered phyllite (rock) may be constructed at 1.5V:1H (subject to
confirmation be a qualified geotechnical engineer). Alternatively, cuts/fills could be retained by engineer
designed retaining walls.
The above recommendations do not supersede any existing safety regulations or legislation applicable to
excavations e.g. limits on personnel entry into trenches.
Batter faces must be protected from erosion (e.g. vegetation or geosynthetic erosion matting).
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PROPOSED RECONFIGURATION OF A LOT
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7.1.4 Filling
Filling of up to 1 m height has been allowed to create level building platforms, from a slope stability point of
view. Fill of greater height shall be supported by an engineer designed retaining wall. Any imported fill must
have a minimum CBR value of 10%, and maximum ‘fines’ content (percent passing 0.075 mm sieve) of 15%.
Future fill must be compacted at moisture contents within the range of ±2% of optimum moisture content for
Standard Compaction. Fill particles greater than 100 mm must be excluded. Fill should be placed in
maximum 250 mm thick (loose thickness) layers and be compacted by repeated rolling to achieve a dry
density ratio of at least 95% of the maximum Dry Density Ratio (Standard Compaction method), or 70% of
the Dry Density Index for cohesionless fills (e.g. sands).
Compaction should be carried out using a minimum 6 tonne smooth drum roller with vibration generally
turned on.
Confirmatory compaction testing must be carried out at regular intervals. Details for inspection and testing of
fill are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and Residential
Developments.
7.1.5 Material Suitability for Re-Use
Excavated material from the development area is expected to comprise mostly silty clays. These materials,
where free of deleterious material (e.g. vegetation, cobbles greater than 150 mm), should be suitable for
placement as structural fill subject to appropriate moisture control.
7.2 Building Foundations
7.2.1 Site Classification
Based on the existing natural soil profile encountered, and laboratory test results, footing design may be
based upon a site classification of Class M according to AS2870:2011, with estimated characteristic surface
movements (‘ys’) of 20 mm to 40 mm. Final site classification and footing design will be dependent on
earthworks, type of fill material placed and degree of fill placement supervision.
It should be noted that the predicted order of movement is based on natural soil profile and moisture content
changes due to normal seasonal moisture variations only. Should high plasticity clay be placed as fill across
the building envelope, a more sever site classification may result.
7.2.2 Footing Design
The future residence on proposed Lot 2 is likely to be one to two storey, and either slab-on-ground or
suspended floor (or a combination). Footing design will depend on earthworks undertaken and building type
(loads). It is recommended that footings are founded at least 0.3 m into the highly weathered phyllite (rock).
Conventional footings beams founded directly on phyllite may be suitable in cut areas, however, where fill is
placed or where excavations do not expose rock close to the surface, ‘bucket piers’ or bored piers would be
required to extend footings to rock.
Footings founded in weathered phyllite rock may be designed using an allowable bearing capacity of
350 kPa. Based on the test pits, founding depths are estimated to range up to about 3 m BGL.
If any subsurface 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.
Subject to design and construction in accordance with the above recommendations, settlements are
expected to be within building serviceability limits (i.e. less than 25 mm).
All footings should found such that they are not adversely affected by any adjacent excavations, batter
slopes, trenches, or retaining walls that are not designed to support loads. To minimise the potential for any
adverse interaction effects, footings should found at least below a plane extending 1 m horizontally from the
19 June 2018
Report No. 17427-001-Rev0 10
Page 16
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
base of trenches/excavations/retaining walls, then rising up at 1V:1H. This requirement is illustrated in Text
Figure 9.
Text Figure 9: Footing depth required to minimise risk of undermining
7.3 Retaining Structures
Design for retaining structures could be carried out using a triangular pressure distribution applicable to the
wall type and based on the parameters listed in Table 4. The values in Table 4 assume that the walls are
fully drained and no allowance is included for hydrostatic pressures, construction loading, up-slope footing
loadings, the effects of sloping ground and backfill compaction stresses.
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)
Residual Material
comprising very stiff to 1.9 27 0.38 0.55 2.66
hard silty clays
EW Material comprising
stiff to very stiff silty 1.8 25 0.41 0.58 2.46
clays
Future fill * * * * *
Note: * Depends on fill material type and level of compaction.
7.4 Pavement Design Parameters
Based on the general nature of the material encountered during the investigation, design of pavements may
be based upon an indicative CBR value of 3 % for the expected silty clay subgrades.
In general, proposed pavement subgrades must be ‘proof rolled’ and visually assessed by an experienced
engineer to ensure no heaving or unacceptable subgrade deflection occurs. Should heaving or deflection
occur, excavation of ‘soft spots’ may be required, followed by reinstatement with compacted select granular
fill.
The recommended design CBR value is applicable to properly drained subgrades only, and must be
confirmed by subgrade inspection and testing by an experienced engineer following earthworks. ‘Properly
drained subgrades’ require open graded drains, site grades that shed water and prevent ponding, and
subsurface drains adjacent to pavements.
19 June 2018
Report No. 17427-001-Rev0 11
Page 17
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
7.5 Drainage
Adequate site drainage must be installed to ensure that surface water runoff is directed away from
pavements and footings.
All excess stormwater collected around the residence (including overflow from rainwater tanks) must be
directed to discharge at least 10 m down slope of any building or fill embankment and towards the gully north
of the proposed building envelope. This should be handled by pipes or lined channels to discharge into a
rock-lined contour drain, stacked rock weir, or similar.
8.0 WASTEWATER TREATMENT AND DISPOSAL
An assessment of the type and configuration of wastewater system(s) that may be suitable for a proposed
development requires:
Assumptions to be made regarding the typical building/worker configuration and probable
wastewater flow; and
Evaluation of the terrain-soil combinations to identify distinct units.
8.1 Wastewater Flow Design Allowance
For a typical four bedroom house (or three bedrooms plus study), we have estimated 6 Equivalent Persons
(EP) total. For each EP, a typical wastewater flow allowance of 115 L/person/day has been taken from
Appendix 4.2D of AS1547:2000. This represents the flow allowance for households with standard water
reduction fixtures and on-site roof water tank supply. We therefore estimate a typical daily household
wastewater flow rate of 6 x 115 = 690 L/day. This gives a weekly flow rate of 7 x 690 L/Day = 4,830 L/week.
It should be noted that the use of extra wastewater producing fixtures (e.g. spa baths) has the potential to
increase the household wastewater flow rate. Final wastewater flow rates must be calculated at the time of
detailed design of the wastewater system, at building stage once the house design is known.
8.2 Terrain-Soil Assessment
The terrain-soil combination(s) encountered at a site are assessed so that an Expected Available Area (EAA)
can be delineated for suitable methods of wastewater treatment and land application.
Possible areas for on-site effluent disposal on Lot 2 include the areas of mature trees adjacent to the
nominated building envelope (provided set-backs can be maintained), and on the grassed slope below. The
terrain on the slopes below the house has been categorised as Linear Planar in accordance with the slope
configurations described in Figure 4.1B2 of AS1547:2000, which also describes the relationship between the
shape of the slope and surface drainage. Such slopes have less effective natural drainage as distance from
the crest increases, with no spreading or acceleration of run-off as it moves down slope.
It has been assessed from the results of the investigation that the soil profiles across the likely effluent
disposal area on Lot 2 are equivalent to Strongly Structured Medium to Heavy Clay (Soil Category 6),
based upon a typical soil profile encountered. This soil classification has been derived via the method
described in Table 4.2A4 of AS1547:2000. The indicative soil permeability rate (Ksat) for a soil of this
category is 0.06 to 0.05 m/d.
8.3 Recommendations
8.3.1 System Type
Having consideration for the terrain-soil assessment and environmental constraints of the site, we have
made an assessment of suitable methods of wastewater treatment for the site. The sewage treatment plant
(STP) connected to the house on Lot 2 must be licensed to produce at least Secondary standard effluent
and verified under the Plumbing and Drainage Act 2002. It is recommended that the STP is connected to a
surface or shallow subsurface drip irrigation system.
19 June 2018
Report No. 17427-001-Rev0 12
Page 18
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
Table 4.2A4 of AS1547:2000 recommends a Design Irrigation Rate (DIR) of 15 mm/week for Category 6 soil.
Therefore, the following land application area is recommended for the drip irrigation system:
4,900 L/week / (15 mm/week) = 322 m2
An indicative 322 m2 wastewater irrigation area is shown in Figure 1, where it can be seen that there is
sufficient room to site the wastewater irrigation area on Lot 2 with sufficient setbacks (including a 30 m setback
from the natural watercourse) and leaving enough space for a 100% reserve area.
8.3.2 System Positioning
Positioning (‘setbacks’) of the irrigation systems must be in accordance with the horizontal and vertical
setback distances recommended in Tables T5 and T7 of the Queensland Plumbing and Wastewater Code
2013, as summarised in Table 5.
Table 5: Horizontal and Vertical Setback/Separation Distances for Irrigation Areas
Site Feature Secondary Effluent Advanced Secondary
Effluent
Horizontal Setback Distances
Property boundary 2 m (up slope or level) and 4 m (down slope)
Buildings 10 m 10 m
Surface Water 30 m 10 m
Bore, well 30 m 10 m
Recreation areas (children’s
play areas, swimming pools, 10 m 10 m
etc.)
In-ground water tank 6m 6m
Retaining wall and
embankments, escarpments, 2 m (up slope or level) and 4 m (down slope)
cuttings
Vertical Separation Distances
Hardpan or bedrock 0.6 m 0.3 m
An unsaturated soil depth of 0.6 m (i.e. depth to rock or wet soil) is recommended for Secondary effluent.
Test pits indicate adequate soil depths are available across the proposed effluent disposal areas.
8.3.3 System Construction
Construction of the wastewater land application areas should be carried out in accordance with Appendix
4.2A of AS1547:2000 and NC requirements. In order to minimise potential undesirable environmental
impacts associated with wastewater application at the site, the following practices should be employed:
Any sandy topsoil material won from stripping works associated with the main construction works
may be used to supplement the soil within the disposal field.
Install surface diversion drainage on the up slope side of the possible effluent disposal area in order
to divert stormwater flows away.
Maintain vegetation on the possible effluent disposal area.
19 June 2018
Report No. 17427-001-Rev0 13
Page 19
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
To evenly distribute wastewater throughout the irrigation area, a pressure equalisation system
should be installed.
Construct irrigation laterals parallel with the natural ground surface contours.
Erect signage at the boundaries of the area in at least two places in accordance with Council
requirements to warn people regarding the presence of wastewater pipes (e.g. “Sewage Effluent
Pipework Installed Below – DO NOT DIG” or “Recycled Water – Avoid Contact - DO NOT DRINK”).
Detailed design of the effluent disposal systems must be carried out by an NC Registered Evaluator to
accompany the plumbing application at the building stage.
8.3.4 Maintenance and Inspection
To comply with NC requirements, the following management and inspection shall be implemented once the
effluent disposal systems are established:
Continuous monitoring by the property owner for any signs of system failure such as septic odour,
seepage, soil and/or plant discolouration.
Should any signs of system failure be observed by the property owner, including the in-built HSTP
failure alarm, the manufacturer shall be contacted immediately to arrange for the necessary repairs.
Quarterly inspection, testing and repair (if necessary) to the HSTP and irrigation area by a Licensed
Inspector (normally a service provided by the HSTP manufacturer).
9.0 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.
19 June 2018
Report No. 17427-001-Rev0 14
Page 20
Tectonic Geotechnical Pty Ltd
PO Box 899
Buderim Qld 4556
M: 0437 755 700 / 0437 756 711
Existing PROJECT:
House
GEOTECHNICAL INVESTIGATION
216 BLACK MOUNTAIN ROAD
BLACK MOUNTAIN
TITLE:
SITE PLAN
CLIENT:
TP1
MURRAY & MICHELLE
RICHARDSON
TP2 DRAWN: DATE:
TP4
RKG 04/06/2018
CHECKED: DATE:
0 40 80m ACD 04/06/2018
TP3
SCALE:
TP5
AS SHOWN
LEGEND:
APPROX TEST PIT LOCATION
SLOPE ANGLE AND
DIRECTION
INDICATIVE EFFLUENT
DISPOSAL AREA OF
Black Mountain Road APPROX 322 m2
PROPOSED BUILDING
0 10 20 30 40m ENVELOPE (AS DEFINED BY
MURRAY & ASSOCIATES)
PROJECT NO.: FIGURE: REV:
Note: Base plans courtesy Near Map 18127 1 0
Page 21
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
APPENDIX A
Test Pit Reports and Explanatory Notes
19 June 2018
Report No. 18127-001-Rev0
Page 22
Borehole No.
TP1
Page 1 of 1
Engineering Log - Test Pit Project No.: 18127
Client: Murray & Michelle Richardson Commenced: 17/05/2018
Project Name: Proposed Reconfiguration of a Lot Completed: 17/05/2018
Hole Location: 216 Black Mountain Road, Black Mountain Logged By: RKG
Hole Position: 486707.0 m E 7078684.0 m N MGA94 Zone 56 Checked By: ACD
Equipment Type and Model: 6t Excavator RL Surface: No survey
Excavation Dimensions: 2.5 m Long 0.6 m Wide Datum: AHD Operator: Bebrok
Excavation Information Soil Description Observations
Relative Density
Classification
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description
Penetrometer Structure and
Condition
Recovery
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Additional Observations
Symbol
Method
secondary and minor components, colour
Water
Remarks RL Depth (kPa)
(m) (m)
100
200
300
400
500
CH Silty CLAY, high plasticity, brown, with fine 0.00: TOPSOIL
grained sand and rootlets
CH 0.10: RESIDUAL
Silty CLAY, high plasticity, orange brown
DS
0.3-0.5m
0.5
becoming pale grey mottled pale orange
brown and red
Not Encountered
1.0 M VSt
with subangular cobbles of phyllite, up to 70 1.00: EW MATERIAL
mm in size
E
TECTONIC 2.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 18127.GPJ <<DrawingFile>> 01/06/2018 16:58 10.0.000 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 2.00.2 2016-10-13 Prj: Tectonic 2.00 2016-02-16
1.5
PHYLLITE, highly to moderately weathered, 1.95: ROCKHEAD
2.0
pale grey stained red brown, very low
strength, thinly laminated fabric
Hole Terminated at 2.30 m
Bucket Refusal
2.5
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure No resistance Level (Date) U - Undisturbed Sample D - Dry VS - Very Soft
X - Existing Excavation ranging to D - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket refusal Inflow CBR- CBR Mould Sample W - Wet F - Firm
R - Ripper VSt - Very Stiff
E - Excavator H - Hard
Plastic Limit VL - Very Loose
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System
Page 23
Borehole No.
TP2
Page 1 of 1
Engineering Log - Test Pit Project No.: 18127
Client: Murray & Michelle Richardson Commenced: 17/05/2018
Project Name: Proposed Reconfiguration of a Lot Completed: 17/05/2018
Hole Location: 216 Black Mountain Road, Black Mountain Logged By: RKG
Hole Position: 486722.0 m E 7078670.0 m N MGA94 Zone 56 Checked By: ACD
Equipment Type and Model: 6t Excavator RL Surface: No survey
Excavation Dimensions: 2.5 m Long 0.6 m Wide Datum: AHD Operator: Bebrok
Excavation Information Soil Description Observations
Relative Density
Classification
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description
Penetrometer Structure and
Condition
Recovery
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Additional Observations
Symbol
Method
secondary and minor components, colour
Water
Remarks RL Depth (kPa)
(m) (m)
100
200
300
400
500
CH Silty CLAY, high plasticity, brown, with fine 0.00: TOPSOIL
grained sand and trace of rootlets St
CH Silty CLAY, high plasticity, pale orange brown 0.20: RESIDUAL
DS
0.3-0.4m St to
VSt
0.5
DS CI becoming orange brown, medium plasticity,
0.6-0.8m trace of fine size angular gravel
1.0
M
Not Encountered
VSt
TECTONIC 2.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 18127.GPJ <<DrawingFile>> 01/06/2018 16:59 10.0.000 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 2.00.2 2016-10-13 Prj: Tectonic 2.00 2016-02-16
E
1.5
CH Silty CLAY. high plasticity, pale grey mottled 1.80: EW MATERIAL
pale orange brown and red, with subangular
cobbles of weathered phyllite up to 100 mm
2.0 St to
VSt
PHYLLITE, highly to moderately weathered, 2.30: ROCKHEAD
pale grey stained red brown and yellow brown,
very low strength, relict bedding planes
2.5 weathered to pale grey silty clay
Hole Terminated at 2.80 m
Limit reach of excavator due to sloped setup
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure No resistance Level (Date) U - Undisturbed Sample D - Dry VS - Very Soft
X - Existing Excavation ranging to D - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket refusal Inflow CBR- CBR Mould Sample W - Wet F - Firm
R - Ripper VSt - Very Stiff
E - Excavator H - Hard
Plastic Limit VL - Very Loose
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System
Page 24
Borehole No.
TP3
Page 1 of 1
Engineering Log - Test Pit Project No.: 18127
Client: Murray & Michelle Richardson Commenced: 17/05/2018
Project Name: Proposed Reconfiguration of a Lot Completed: 17/05/2018
Hole Location: 216 Black Mountain Road, Black Mountain Logged By: RKG
Hole Position: 486717.0 m E 7078655.0 m N MGA94 Zone 56 Checked By: ACD
Equipment Type and Model: 6t Excavator RL Surface: No survey
Excavation Dimensions: 2.5 m Long 0.6 m Wide Datum: AHD Operator: Bebrok
Excavation Information Soil Description Observations
Relative Density
Classification
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description
Penetrometer Structure and
Condition
Recovery
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Additional Observations
Symbol
Method
secondary and minor components, colour
Water
Remarks RL Depth (kPa)
(m) (m)
100
200
300
400
500
CH Silty CLAY, high plasticity, brown, with fine 0.00: TOPSOIL
grained sand and trace of rootlets St
CH Silty CLAY, high plasticity, pale orange brown, 0.15: RESIDUAL
with medium size subangular gravel
VSt
to H
0.5
U65 CI becoming orange brown, medium plasticity,
0.6-1.1m trace of fine size angular gravel
1.0 1.00: EW MATERIAL
CH Silty CLAY. high plasticity, pale grey mottled
pale orange brown and red, with subangular, M
tabular, cobbles of weathered phyllite up to 85
mm
TECTONIC 2.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 18127.GPJ <<DrawingFile>> 01/06/2018 16:59 10.0.000 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 2.00.2 2016-10-13 Prj: Tectonic 2.00 2016-02-16
Not Encountered
1.5
E
H
2.0
becoming gravelly, medium to coarse size,
subangular
D to
2.5 M
PHYLLITE, highly to moderately weathered, 2.70: ROCKHEAD
pale grey stained red brown and yellow brown,
very low strength, relict bedding planes
weathered to pale grey silty clay
3.0
Hole Terminated at 3.00 m
Bucket Refusal
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure No resistance Level (Date) U - Undisturbed Sample D - Dry VS - Very Soft
X - Existing Excavation ranging to D - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket refusal Inflow CBR- CBR Mould Sample W - Wet F - Firm
R - Ripper VSt - Very Stiff
E - Excavator H - Hard
Plastic Limit VL - Very Loose
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System
Page 25
Borehole No.
TP4
Page 1 of 1
Engineering Log - Test Pit Project No.: 18127
Client: Murray & Michelle Richardson Commenced: 17/05/2018
Project Name: Proposed Reconfiguration of a Lot Completed: 17/05/2018
Hole Location: 216 Black Mountain Road, Black Mountain Logged By: RKG
Hole Position: 486693.0 m E 7078668.0 m N MGA94 Zone 56 Checked By: ACD
Equipment Type and Model: 6t Excavator RL Surface: No survey
Excavation Dimensions: 2.5 m Long 0.6 m Wide Datum: AHD Operator: Bebrok
Excavation Information Soil Description Observations
Relative Density
Classification
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description
Penetrometer Structure and
Condition
Recovery
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Additional Observations
Symbol
Method
secondary and minor components, colour
Water
Remarks RL Depth (kPa)
(m) (m)
100
200
300
400
500
CH Silty CLAY, high plasticity, brown, with fine St 0.00: TOPSOIL
grained sand and trace of rootlets 0.05: RESIDUAL
DS CH
VSt
0.1-0.3m Silty CLAY, high plasticity, orange brown
to H
U65
0.15-0.55m
CH Silty CLAY, pale grey mottled red and yellow 0.30: EW MATERIAL
brown, with coarse size gravel and cobbles of
phyllite up to 75 mm
0.5
VSt
1.0 M
Not Encountered
TECTONIC 2.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 18127.GPJ <<DrawingFile>> 01/06/2018 17:00 10.0.000 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 2.00.2 2016-10-13 Prj: Tectonic 2.00 2016-02-16
E
1.5 VSt
to H
2.0 2.00: ROCKHEAD
PHYLLITE, highly to moderately weathered,
pale grey stained red brown, very low
strength, thinly laminated fabric
2.5
Hole Terminated at 2.70 m
Bucket Refusal
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure No resistance Level (Date) U - Undisturbed Sample D - Dry VS - Very Soft
X - Existing Excavation ranging to D - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket refusal Inflow CBR- CBR Mould Sample W - Wet F - Firm
R - Ripper VSt - Very Stiff
E - Excavator H - Hard
Plastic Limit VL - Very Loose
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System
Page 26
Borehole No.
TP5
Page 1 of 1
Engineering Log - Test Pit Project No.: 18127
Client: Murray & Michelle Richardson Commenced: 17/05/2018
Project Name: Proposed Reconfiguration of a Lot Completed: 17/05/2018
Hole Location: 216 Black Mountain Road, Black Mountain Logged By: RKG
Hole Position: 486669.0 m E 7078651.0 m N MGA94 Zone 56 Checked By: ACD
Equipment Type and Model: 6t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Soil Description Observations
Relative Density
Classification
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description
Penetrometer Structure and
Condition
Recovery
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Additional Observations
Symbol
Method
secondary and minor components, colour
Water
Remarks RL Depth (kPa)
(m) (m)
100
200
300
400
500
CH Silty CLAY, high plasticity, brown, with fine 0.00: TOPSOIL
grained sand and rootlets
CH Silty CLAY, high plasticity, orange brown, with
trace of medium to coarse size subangular St
gravel
0.5
0.60: RESIDUAL
1.0
Not Encountered
M
1.20: EW MATERIAL
TECTONIC 2.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 18127.GPJ <<DrawingFile>> 01/06/2018 17:00 10.0.000 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 2.00.2 2016-10-13 Prj: Tectonic 2.00 2016-02-16
Silty CLAY. high plasticity, pale grey mottled VSt
E
pale orange brown and red, with medium size,
subangular gravel, and subangular, tabular,
cobbles of weathered phyllite up to 85 mm
1.5
St to
2.0
VSt
PHYLLITE, highly to moderately weathered, 2.10: ROCKEHAD
pale grey stained red brown, very low
strength, thinly laminated fabric
2.5
Hole Terminated at 2.50 m
Bucket Refusal
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure No resistance Level (Date) U - Undisturbed Sample D - Dry VS - Very Soft
X - Existing Excavation ranging to D - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket refusal Inflow CBR- CBR Mould Sample W - Wet F - Firm
R - Ripper VSt - Very Stiff
E - Excavator H - Hard
Plastic Limit VL - Very Loose
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System
Page 27
TERMS USED ON LOGS
DRILLING/EXCAVATION METHOD
AD* Auger Drilling RD Rotary Blade or Drag bit NQ Diamond Core - 47 mm
*V V-Bit RT Rotary Tri-cone bit NMLC Diamond Core - 52 mm
*T TC-Bit RA Rotary Air HQ Diamond Core - 63 mm
HA Hand Auger HMLC Diamond Core – 63mm
ADH Hollow Auger BH Tractor Mounted Backhoe
HA Hand Auger EX Tracked Hydraulic Excavator
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
FV Field vane shear 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
Rev0
October 2013
Page 28
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 29
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
BP Bedding parting Cn Clean POL Polished
X Foliation Sn Stain S Smooth
C Contact Vr Veneer SL Slickensided
L Cleavage Ct Coating or Infill S Smooth
JT Joint Clay Clay RF Rough
SS/SZ Sheared seam/zone (Fault) Fe Iron oxide VR Very rough
Qz Quartz Planarity
CS/CZ Crushed seam/zone (Fault)
DS/DZ Decomposed seam/zone PR Planar
IS/IZ Infilled seam/zone UN Undulating
S Schistocity ST Stepped
V Vein
DB Drilling break
Rev3
October 2017
Page 30
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
APPENDIX B
Laboratory Test Certificate
19 June 2018
Report No. 18127-001-Rev0
Page 31
Brisbane Laboratory
Coffey Services Australia Pty Ltd
ABN 55 139 460 521
86A Yarraman Place
Virginia QLD 4014
Phone: +61 7 3608 2500
Fax: +61 7 3852 2805
Report No: SSI:BRIS18S-01583
Shrink Swell Index Report
Issue No: 1
Client: Tectonic Geotechnical Pty Ltd Accredited for compliance with ISO/IEC 17025 -
Testing.
40 Glenn Vista Place
Chevallum QLD 4555 The results of the tests, calibrations and/or
measurements included in this document are traceable
to Australian/national standards.
Principal:
Project No.: 754-BRIS00134AA Approved Signatory: Joseph Langley
Project Name: Laboratory Testing (Laboratory Manager)
Lot No.: TRN: 18127
NATA Accredited Laboratory Number:431
Date of Issue: 12/06/2018
Sample Details
Sample ID: BRIS18S-01583 Sampling Method: Submitted by client
Date Sampled: 17/05/2018 Material: In Situ
Date Submitted: 25/05/2018 Source: On site
Date Tested: 5/06/2018
Project Location: 216 Black Mountain Road
Sample Location: TP4, 0.15m
Borehole Number:
Borehole Depth (m):
Swell Test AS 1289.7.1.1 Shrink Test AS 1289.7.1.1
Swell on Saturation (%): -0.7 Shrink on drying (%): 2.2
Moisture Content before (%): 21.7 Shrinkage Moisture Content (%): 25.6
Moisture Content after (%): 28.6 Est. inert material (%): 0
Est. Unc. Comp. Strength before (kPa): Crumbling during shrinkage: 0
Est. Unc. Comp. Strength after (kPa): Cracking during shrinkage: Slight
Shrink Swell
Shrink Swell Index - Iss (%): 1.2
Comments
Form No: 18932, Report No: SSI:BRIS18S-01583 © 2000-2016 QESTLab by SpectraQEST.com Page 1 of 1
Page 32
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
APPENDIX C
AGS 2007 Practice Note Guidelines for Landslide Risk
Management
Qualitative Terminology for Use in Assessing Risk to
Property
19 June 2018
Report No. 18127-001-Rev0
Page 33
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 34
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 35
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 36
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
114 Australian Geomechanics Vol 42 No 1 March 2007
Form No. 68029 RL2 August 2010
Page 37
PROPOSED RECONFIGURATION OF A LOT
216 BLACK MOUNTAIN ROAD, BLACK MOUNTAIN
APPENDIX D
Limitations
19 June 2018
Report No. 18127-001-Rev0
Page 38
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)