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slope stability
14 September 2022 Project No. 22340-001-Rev0
Integra Partnerships
Attention: Alex Smith
Email: [email protected]
GEOTECHNCIAL INVESTIGATION
PROPOSED RESIDENCES
12 - 14 WYANDRA STREET, NOOSA
Dear Alex,
1.0 INTRODUCTION
As requested, Tectonic has undertaken a geotechnical investigation for proposed residences at 12 – 14
Wyandra Street, Noosa. This report presents the results of our investigation, together with geotechnical
recommendations for the project regarding site classification, earthworks, footing design and drainage.
1.1 Details of the Site and Development
The sites are described as Lot 43 and 44 on RP139776, covering an overall area of about 1581 m2, and
have frontages to Wyandra Street to the north. At the time of the investigation, existing residences with
associated swimming pools were present. Similar residential allotments with houses surrounded the site in
all directions. A 2022 aerial image of the site and surrounds is shown in Text Figure 1 below. A more
detailed description of the site is given in Section 2.
Subject Sites
Text Figure 1: Aerial image of site and surrounds from 2022 (courtesy of Nearmap imagery)
Architectural drawings supplied to Tectonic (Blackwood Architecture and Design, Project No.’s 202247
rev E and 202303 rev A, Dwg No’s DA1.01 to DA5.01, dated 25 & 26 August 2022) indicate that the
proposed residential developments will comprise the following:
Demolition of the existing residences and swimming pools.
Earthworks to provide terraced level building pads.
Construction of terraced two-storey duplexes including swimming pools on each lot.
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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Integra Partnerships 22340-001-Rev0
14 September 2022
Construction is likely to comprise a combination of lightweight materials (e.g. timber, sheet metal roof etc.),
rendered brick/masonry blockwork (or similar) and suspended concrete slabs. No earthworks details were
available at the time of reporting; however, provided drawings indicate that, cut and fill earthworks less than
1.0 m height will be required. Localised deeper excavations will be required for the proposed swimming
pools.
The properties have existing connections to town water and sewerage. A site layout plan and an elevation
view of the proposed duplexes are shown in Text Figures 2 and 3 below.
Text Figure 2: 12 Wyandra St, Proposed site layout (LHS) and rendering of the proposed residences (RHS)
Text Figure 3: 14 Wyandra St, Proposed site layout (LHS) and rendering of the proposed residences (RHS)
1.2 Method and Scope of Investigation
As part of our investigation, a desk-top study was carried out comprising a review of published geological
maps and available geotechnical data. A walk-over survey was conducted in order to make an appraisal of
the general condition of the site in regard to topography, drainage, vegetation cover, geology, erosion, and
condition of existing structures.
The walk-over survey was carried out by an experienced geotechnical engineer from Tectonic on
29 August 2022. The walk-over inspection was combined with a geotechnical investigation comprising
drilling of four boreholes (BH1 and BH4) around the existing residence to depths of 2.8 m to 3.0 m below
ground level (BGL). The boreholes were drilled with a hand auger, at the approximate locations shown in
Figure 1 attached to this report. In situ testing, using the dynamic cone penetrometer (DCP) method, was
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Integra Partnerships 22340-001-Rev0
14 September 2022
carried out from the ground surface and extending below the borehole termination depth to between 4.0 m
and 4.7 m BGL.
The borehole logs and explanatory notes are attached to this report. The results of the desk-top study, walk-
over survey and borehole drilling are included in Section 2 below.
1.3 Qualifications of Responsible Engineer
This report has been reviewed by Mr Ashley Davey, an RPEQ with over 27 years of experience in
geotechnical engineering, including a number of slope stability projects on the Sunshine Coast.
2.0 DESCRIPTION OF EXISTING CONDITIONS
2.1 Geology and Subsurface Conditions
Available geological information 1 indicates that the site is underlain by Pleistocene age parabolic dunes
(“Qpd/2”) comprising “quartz sand” (Ref. Text Figure 4).
Approx. site location
Text Figure 4: Extract from Laguna Bay Geology Map
The boreholes encountered relatively consistent subsurface conditions, summarised as follows:
Fill – Borehole BH1 only, comprising very loose to loose silty sand to 0.4 m depth, then
Natural Sands – initially comprising very loose to loose silty sand/sand to depths between 1.8 m
and 2.5 m BGL, then becoming medium dense to the borehole termination depths (2.8 m to 3 m
BGL).
Results of the DCP testing completed below the borehole termination depths indicated inferred dense
sands at depths of 2.9 m to 3.8 m BGL extending to the DCP termination depths of 4.0 m to 4.7 m BGL.
Groundwater was not encountered during drilling of the boreholes, with the soils being moist.
1
1:100,000 Laguna Bay Surface Geology, Sheet 9545, Compilation Map, DNRME, 2018
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Integra Partnerships 22340-001-Rev0
14 September 2022
2.2 Topography
During the site walk-over, topographic features specific to the site were noted, and ground slopes were
recorded using a hand-held clinometer. As illustrated in Text Figure 5, the sites are located on a gently
sloping, westerly facing flank of an ancient sand dune, which crests about 25 m to the north-east.
12 Wyandra Street generally sloped to the west and 14 Wyandra Street sloped to the south. The natural
ground slopes across the properties were measured to generally range between about 2° to 5°. The south-
western corner of 12 Wyandra Street sloped from the pool to the boundary at about 8°.
Subject Sites
Text Figure 5: Ground surface contours, 1 m spacing (courtesy NC interactive mapping)
Site conditions at the time of our investigation are shown in Text Figures 6 to 8 below and on the following
page.
#14
#12
Text Figure 6: Panoramic view south across the existing residences
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Integra Partnerships 22340-001-Rev0
14 September 2022
Text Figure 7: General condition of existing residence at 12 Wyandra Street
Text Figure 8: General condition of existing residence at 14 Wyandra Street
2.3 Groundwater
No signs of groundwater seepage (‘springs’) were observed during our walk-over, nor was groundwater
encountered in the boreholes, with soils being moist.
2.4 Surface Drainage
Given the topography, the limited upslope stormwater catchment would be anticipated to be intercepted by
the existing drainage infrastructure along Wyandra Street. Given the sandy nature of the site and
surrounds, rainfall would normally be anticipated to infiltrate the ground surface. No evidence of significant
erosion was observed across the subject site.
2.5 Vegetation
Landscaping was present around the perimeter of the houses, comprising dense shrubbery and several
mature trees. The mature trees were noted to be relatively straight, exhibiting no obvious signs of distortion
which could be indicative of global slope instability.
2.6 Buildings and Other Structures
The existing residence was a single storey, slab on ground, brick veneer structure with swimming pool at
12 Wyandra Street, with a two-storey, blockwork and weatherboard dwelling with swimming pool at
14 Wyandra Street.
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Integra Partnerships 22340-001-Rev0
14 September 2022
3.0 RECOMMENDATIONS
3.1 Site Layout and Development Limitations
Should any revisions be made to the extent of the proposed duplexes described in Section 1.1, Tectonic must
review these prior to construction to assess if there are any impacts on our recommendations.
No earthworks details were available at the time of reporting; however, provided drawings indicate that cut
and fill earthworks less than 1.0 m height will be required. Should proposed cuts/fills exceed these quantities,
Tectonic should assess the impacts on slope stability before construction.
3.2 Earthworks
3.2.1 Site Preparation and Trafficability
In construction areas, any relict construction elements, vegetation, tree stumps and large roots should be
stripped and ‘grubbed out’. Any organic rich topsoil or ‘uncontrolled’ fill should also be stripped and removed
from site, based on the boreholes, depths should generally range up to about 0.4 m depth. Organic topsoils
and garden soils must not be re-used as structural fill; however, small volumes may be retained on site for
later use across landscaping areas, if required.
The natural subgrade following stripping will likely be in a loose condition. Where slab on ground
construction is proposed, the compaction of such relatively ‘clean’ sands as structural fill requires the
addition of substantial volumes of water (‘flooding’) combined with the use of vibratory compaction
equipment (typically a vibrating plate).
Care must be taken with the use of vibratory equipment to ensure that there are no adverse impacts on
surrounding structures and underground services. The impacts from ground vibration must be closely
monitored and managed during construction. It would be prudent to conduct a dilapidation survey of
neighbouring structures prior to commencement of construction.
3.2.2 Filling
The existing sandy soils (excluding topsoil) may be reused as structural fill, subject to appropriate moisture
adjustment. It should be noted that compaction of such relatively ‘clean’ sands as structural fill requires the
addition of substantial volumes of water (‘flooding’) combined with the use of vibratory compaction
equipment (typically a minimum 4 tonne vibrating smooth drum roller or vibrating plate) to achieve required
compaction.
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. Select fill should have a maximum particle size of 100 mm for an uncompacted layer
thickness of 200 mm and shall be compacted by repeated rolling with a small compactor to achieve a dry
density ratio of at least 95% of the Standard Maximum Dry Density for cohesive soils, or 70% Dry Density
Index for any imported cohesionless soils.
Confirmatory compaction testing should 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.
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3.2.3 Excavations
Excavations through the fill and natural soils encountered in the boreholes should be achievable using
conventional earthmoving plant (e.g. small excavators). Non-surcharged temporary cuts in the very loose to
loose sands could be formed at 1V:2H, and at 1V:1.5H in medium dense (or denser) sand, for batters up to
2 m in height. Although unlikely, if groundwater seepage is encountered or if sloughing of dry sand occurs at
the batter surface, flatter batters or temporary retention may be required. Deeper cuts, if required, should be
specifically assessed by Tectonic.
Permanent batters up to 1 m high (vertical height) may be battered no steeper than 1V:2.5H. All remaining
permanent cut/fill batters must be supported by engineer designed retaining walls. Any permanent soil and fill
batters will require erosion protection (e.g. revegetation or surface protection).
If the above temporary batter slopes cannot be achieved, due to spatial restraints, temporary shoring would
be required (e.g. sheet piles, contiguous pile wall etc.). Excavations in close proximity to existing structures
and infrastructure, including on neighbouring properties, will need to be specifically designed to prevent
undermining.
If undermining is a potential issue the neighbouring structures may need to be underpinned or excavations
may require temporary shoring. The advice of a suitably qualified and experienced structural RPEQ must be
sought regarding any potential undermining and design and construction of any underpins/temporary shoring
(if required).
The above recommendations do not supersede any existing safety regulations or legislation applicable to
excavations (e.g. limits on personnel entry into trenches).
Due to the highly permeable nature of the sands at this site, stormwater is expected to rapidly infiltrate the
ground, making un-sealed surface drainage ineffective for the control of flows. Any sealed areas should be
graded to ensure free drainage of stormwater away from construction areas, and to a control point(s).
3.3 Site Classification
Due to the insufficient bearing capacity of the very loose to loose sand and probability of ‘uncontrolled’ fill
associated with the demolished residences, the site is classified as Class P in accordance with AS2870-
2011 Residential Slabs and Footings. However, it is assessed that the existing soil profile would exhibit
the characteristics of Class S, with the estimated characteristic surface movements (‘ys’) ranging up to
about 20 mm. Due to the potential variability in subgrade density, and allowing for some settlement of the
loose sands, a site classification of Class M is recommended in relation to assessment of flexibility
requirements for ground slabs, footing and plumbing design).
The use of reactive fill materials (clays) can adversely affect the characteristic ground surface movement,
and must be considered during design if fill material other than sand is proposed to be used on the site.
3.4 Footings
No design loadings were available at the time of reporting. High level footings should not be utilised due to
insufficient bearing capacity and the potential for excessive settlements in the loose upper sands
encountered in the boreholes. Footings for the proposed residence and ancillary structures (e.g. water
tanks, retaining walls etc.) must penetrate through any fill materials and unsuitable natural soils (i.e. very
loose to loose sands) to found at least 0.5 m into medium dense (or denser) sands which were encountered
at depths between 1.8 m and 2.5 m BGL in the boreholes. A minimum founding depth of 3 m BGL (existing
ground levels) is recommended.
Given the sandy soil profile and depth of footings required below existing ground levels, steel screw piles
could be adopted. Due to the presence of loose sands, together with the close proximity to surrounding
infrastructure, open bored piers or driven piles are not considered to be suitable for this site. Steel reinforced
concrete bored piles could be feasible; however, the use of sacrificial liners (e.g. ‘formatube’) would be
required to prevent the caving of upper loose sands.
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Integra Partnerships 22340-001-Rev0
14 September 2022
Steel reinforced concrete bored piles founded as noted above may be designed using an allowable end
bearing pressure of 300 kPa. Parameters for screw pile design are given in Table 1 below. Settlements
under such pressures should be no more than about 25 mm.
Table 1: Screw Pile Design Parameters
Ultimate Allowable
Bearing
Unit weight Friction angle, Bearing Bearing
Founding Material Capacity
(kN/m3) Ø (°) Capacity fbult Capacity fball
Factor, Nq
(kPa) (kPa)
Medium dense natural
18 32 25 1200 400 (Note 1)
sand
Dense to very dense (or
19 36 35 1800 600
denser) natural sand
Notes:
1) Allowable pressure based on a working stress factor of safety value of 3 on the ultimate pressure. If a limit state
design methodology is adopted the ultimate bearing capacity may be used and must be multiplied by a
geotechnical reduction factor Øg determined in accordance with AS2159-2009 to obtain the Design
Geotechnical Strength (Rd,g).
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.
If steel screw piles are adopted, it will be important to ensure close supervision of installation, as piling may
not encounter sufficient drilling resistance (from torque measurement) in sands at the suggested founding
depth, and piles could extend to much greater depth than necessary.
It is therefore recommended that site specific static load testing be conducted from screw piles, if adopted, at
a minimum. Where tension or compression capacity developed in the footings is critical for the future
structure (e.g. resistance to uplift forces from high winds), then cyclic load tests (including measurement of
deflections under tension and compression cycles) should also be undertaken prior to construction.
Kentledge for static testing, or simulated cyclic loads, should prove the piles to a minimum of two times the
expected working load within tolerable deflections.
All footings should be founded such that they are not adversely affected by or affect any adjacent
excavations, trenches, retaining walls, or in ground structures that are not designed to support building
loads. Footings should be founded 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 9
overleaf.
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Integra Partnerships 22340-001-Rev0
14 September 2022
Text Figure 9: Footing depth required to prevent undermining
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.
Should bored piles be adopted, it is essential that the piling contractor have a ‘mud bucket’ or similar to
enable clean out of the pile bases. It is recommended that bored pile sockets be inspected by a suitably
qualified and experienced RPEQ prior to placement of steel reinforcement and pouring of concrete to confirm
allowable bearing pressures and cleanliness.
3.5 Retaining Walls
Retaining structures must be founded as per the recommendations in Section 3.4 above. 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.
The parameters outlined in Table 4 may be adopted for retaining wall design. 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. Any temporary
shoring required to support excavations during construction may also be designed using the parameters in
Table 2.
Table 2: Retaining Structure Design Parameters
Lateral earth pressure coefficients
Unit Friction
Retained material weight angle Ø
Ka Ko
(kN/m3) (°) Kp
(Cantilever wall) (Non-yielding wall)
Very Loose/ Loose
17 28 0.36 0.53 2.77
Sands
Medium Dense (or
18 32 0.31 0.47 3.25
Denser) Sands
Future Fill * * * * *
Note: * depends on fill material type and level of compaction
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Integra Partnerships 22340-001-Rev0
14 September 2022
3.6 Drainage
Given the sandy nature of the site, rainfall is generally expected to rapidly infiltrate any unsealed surfaces. If
necessary, diversion drainage should be constructed to divert seepage and/or runoff away from the building
pad areas and batter slopes to prevent saturation and erosion.
Permanent site drainage must be installed to ensure that stormwater runoff is directed away from proposed
building walls, footings and retaining walls (e.g. positive gradients and/or channel drains). Future building
and landscaping must be carried out to maintain good drainage. Surface diversion drainage should be
constructed above the crest of any new cut or fill embankments (e.g. grassed or landscaped swales or
diversion mounds).
Although unlikely, if groundwater seepage is encountered during excavations, Tectonic must be notified to
assess the impact on stability.
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 buildings (including overflow from rainwater tanks, pool etc.)
must be directed by pipes or lined channels to discharge into the existing stormwater infrastructure along
Wyandra Street.
Subsurface disposal of stormwater, such as by an infiltration pit, must not be undertaken.
4.0 LIMITATIONS
Your attention is drawn to the document Limitations, which is attached to this letter report.
Please contact the undersigned should you wish to discuss any of the above matters.
Yours faithfully
TECTONIC GEOTECHNICAL PTY LTD
Jarrad McVey BEng (Civil) MIEAust Ashley Davey BEng (Geological) RPEQ 8159
Geotechnical Engineer Principal Geotechnical Engineer
Attachments: Figure 1 – Site Plan
Borehole Reports and Explanatory Notes
Limitations
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Tectonic Geotechnical Pty Ltd
PO Box 899
Buderim Qld 4556
Office: 07 5478 9016
Email: [email protected]
BH3
PROJECT:
PROPOSED RESIDENCES
12 – 14 WYANDRA STREET
NOOSA
TITLE:
SITE PLAN
BH1
CLIENT:
INTEGRA PARTNERSHIPS
BH4 DRAWN: DATE:
JPM 12/09/2022
CHECKED: DATE:
ACD 13/09/2022
BH2 SCALE:
AS SHOWN
LEGEND:
Approx. Borehole Locations
Notes: PROJECT NO.: FIGURE: REV:
Aerial imagery courtesy of Nearmap (14 August 2022) 0 5 10 15 20 m
22340-001 1 0
Page 12
Borehole No.
BH1
Page 1 of 1
Engineering Log - Borehole Project No.: 22340
Client: Integra Partnerships Commenced: 29/8/2022
Project Name: Proposed Residences Completed: 29/8/2022
Hole Location: 12-14 Wyandra Street, Noosa Logged By: LM
Hole Position: 508919.2 m E 7079992.2 m N MGA2020 Zone 56 Checked By: ACD
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: LM/WD
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
Silty SAND (FILL), fine to medium grained,
brown, with fine to medium sized gravels
SM Silty SAND, fine to medium grained, grey to pale
grey (RESIDUAL)
VL to
1
SP SAND, fine to medium grained, pale grey L
Not Encountered
M
HA
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 22340.GPJ <<DrawingFile>> 13/9/2022 12:02 10.02.00.04 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
2
L
MD
Augered to 3.0m
3
Hole Terminated at 3.00 m
Target depth
4
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 13
Borehole No.
BH2
Page 1 of 1
Engineering Log - Borehole Project No.: 22340
Client: Integra Partnerships Commenced: 29/8/2022
Project Name: Proposed Residences Completed: 29/8/2022
Hole Location: 12-14 Wyandra Street, Noosa Logged By: LM
Hole Position: 508945.0 m E 7079982.0 m N MGA2020 Zone 56 Checked By: ACD
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: LM/WD
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
SM Silty SAND, fine to medium grained, trace of fine
DS to medium sized gravel and medium plasticity
0.1-0.3m clay
without gravel and clay
SP SAND, fine to medium grained, dark grey to grey VL
1
Not Encountered
M
HA
Augered to 1.9m
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 22340.GPJ <<DrawingFile>> 13/9/2022 12:02 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
2
MD
Augered to 3.0m
3
Hole Terminated at 3.00 m
Target depth
4
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 14
Borehole No.
BH3
Page 1 of 1
Engineering Log - Borehole Project No.: 22340
Client: Integra Partnerships Commenced: 29/8/2022
Project Name: Proposed Residences Completed: 29/8/2022
Hole Location: 12-14 Wyandra Street, Noosa Logged By: LM
Hole Position: 508946.0 m E 7080008.0 m N MGA2020 Zone 56 Checked By: ACD
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: LM/WD
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
SM Silty SAND, fine to medium grained, dark grey
VL
becoming dark grey to grey
1
Not Encountered
M L
HA
becoming pale grey
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 22340.GPJ <<DrawingFile>> 13/9/2022 12:02 10.02.00.04 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
2
MD
3
Hole Terminated at 3.00 m
Target depth Augered to 3.2m
4
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 15
Borehole No.
BH4
Page 1 of 1
Engineering Log - Borehole Project No.: 22340
Client: Integra Partnerships Commenced: 29/8/2022
Project Name: Proposed Residences Completed: 29/8/2022
Hole Location: 12-14 Wyandra Street, Noosa Logged By: LM
Hole Position: 508969.0 m E 7079990.0 m N MGA2020 Zone 56 Checked By: ACD
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: LM/WD
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
SM Silty SAND, fine to medium grained, dark grey
DS
0.2-0.4m
becoming dark grey to grey
VL
1
Not Encountered
SP SAND, fine to medium grained, grey to pale grey
M
HA
L
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 22340.GPJ <<DrawingFile>> 13/9/2022 12:02 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
2
Augered to 2.3m
MD
Hole Terminated at 2.80 m
Due to collapsing sands
3
4 20/80mm
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 16
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 17
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 18
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)