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Response to Info Request - Attachment 5 - Geotechnical Report MCU18-0015 & RAL18-0001 · MCU18/0015
GEOTECHNICAL INVESTIGATION REPORT
PROPOSED DEVELOPMENT
27 ATTUNGA HEIGHTS, NOOSA HEADS
Prepared for:
Novato Group Pty Ltd
C/- Innovative Planning Solutions Pty Ltd
45 First Avenue
Mooloolaba QLD 4557
Email: [email protected]
Report Number: J000635-002-R-Rev1
November 2018
Core Consultants Pty Ltd
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Table of Contents
1.0 INTRODUCTION .................................................................................................................................... 1
2.0 PROPOSED DEVELOPMENT ............................................................................................................... 2
3.0 SITE DESCRIPTION .............................................................................................................................. 2
4.0 METHOD OF INVESTIGATION ............................................................................................................. 3
4.1 Fieldwork – Boreholes ............................................................................................................................ 3
4.2 Fieldwork - MASW Seismic Testing ....................................................................................................... 3
5.0 INVESTIGATION FINDINGS .................................................................................................................. 4
5.1 Geological Mapping ................................................................................................................................ 4
5.2 Ground Conditions .................................................................................................................................. 5
6.0 GEOTECHNICAL DISCUSSION & RECOMMENDATIONS .................................................................. 5
6.1 Earthworks .............................................................................................................................................. 5
6.1.1 Site preparation & trafficability ............................................................................................................ 5
6.1.2 Excavations ........................................................................................................................................ 6
6.1.3 Filling................................................................................................................................................... 6
6.1.4 Batter slopes ....................................................................................................................................... 6
6.1.5 Excavation support ............................................................................................................................. 6
6.2 Retaining Wall Design and Parameters.................................................................................................. 7
6.3 Foundation Design and Parameters ....................................................................................................... 7
6.3.1 High-level footings .............................................................................................................................. 7
6.3.2 Piles .................................................................................................................................................... 8
6.4 Drainage & Erosion Control .................................................................................................................... 9
7.0 SLOPE STABILITY ASSESSMENT & RECOMMENDATIONS ............................................................. 9
7.1 Qualitative Slope Stability Assessment ................................................................................................ 10
7.2 Slope Stability Modelling....................................................................................................................... 10
8.0 LIMITATIONS ....................................................................................................................................... 11
Tables
Table 1: Summary of Geotechnical Items from Noosa Council Information Request, and associated
responses. ......................................................................................................................................................... 1
Table 2: Seismic Data Acquisition Parameters. ................................................................................................ 4
Table 3: Retaining Structure Design Parameters. ............................................................................................. 7
Table 4: Pile Design Parameters. ...................................................................................................................... 8
Table 5: Stability Risk Levels. .......................................................................................................................... 10
Table 6: Qualitative Risk Assessment for Property (Based on AGS 2007)..................................................... 10
Figures
Figure 1 – Site Plan
Figure 2 – Seismic (MASW) Testing
Figure 3 – Slope Stability Modelling
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Appendices
APPENDIX A Reports of Boreholes and Explanatory Notes
APPENDIX B AGS Practice Note Guidelines for Landslide Risk Management
APPENDIX C Limitations
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1.0 INTRODUCTION
As requested by Innovative Planning Solutions Pty Ltd (IPS), this report responds to Items 1 to 7, 10 and 13
in Noosa Council’s information request MCU18/0015 (IR) regarding a proposed development at 27 Attunga
Heights, Noosa Heads.
A geotechnical report for a proposed development on the site was undertaken by Golder Associates in 2003
(refer report 03632248-001). Further geotechnical assessment was provided by Core Consultants in 2015
(refer report J000128-001-L-Rev0) following an amendment to the proposed development layout. The layout
has changed again since our 2015 report, and this report addresses the currently proposed development,
based on architectural plans produced by Tim Ditchfield Architects (refer Project No. 1830, DWG No. DD 02
– P2, dated September 2018).
The IR items and our responses are summarised in Table 1.
Table 1: Summary of Geotechnical Items from Noosa Council Information Request, and associated responses.
Item Information Required Response
1 “Update the Golder Associates and Core Consultants reports This report addresses the current development
(Available to address the geotechnical design and construction issues layout.
Reports) relevant to the currently proposed development layout.”
2 “Provide an accurate slope analysis plan of the site.” Refer to the attached Figure 1.
(Slope Angles)
3
“Provide information on the subsurface conditions Refer to Section 5.2 for subsurface conditions,
downslope of the units and towards the creek to assess and Section 7 for slope stability assessment.
(Subsurface
stability on site. Provide an assessment of the ground
Conditions)
conditions in relation to the stability of the site.”
“Provide information to monitor and maintain water quality of The information required is not of a
the creek, both during construction and the proposed use of geotechnical nature and does not relate to the
4 the site.”
(Slope Stability)
issue described in Item 4 (i.e. slope stability).
Refer to Section 7 for slope stability
assessment.
5 “Provide information regarding the stabilisation of the site, Refer to Section 7 for slope stability
(Overview of both during construction and the proposed use of the site.” assessment and Sections 6 and 7 for
Approach to associated recommendations regarding
Slope Stability) stabilisation of the site.
“i. Advice is required on the locations to which the footing i. The footing advice in the Golder report and
design recommendations apply. Do these recommendations the recommendations in this report should
apply to all footings or only those footings within 20 m of the apply to all footings
creek?
6 ii. Refer to Section 6.3 for lateral load
ii. The method to be adopted in estimating the lateral loads
(Footings)
on the piles should be confirmed. There are several calculations
approaches available for this design. iii. Refer to Section 6.3 for geotechnical design
iii. The geotechnical design parameters to be adopted in the parameters
design should be confirmed”
“i. Slope stability analyses should be provided to show that i. Refer to Section 7 for slope stability
the proposed filling and retention system has an adequate assessment
factor of safety against both local and global instability. ii. Refer to Sections 6.1.1 and 6.1.3 for site
ii. Site specific recommendations are required on site
preparation recommendations
preparation prior to filling given the presence of very loose
7 and loose sand. iii. Refer to Section 6.3 for footing
(Access iii. Site specific recommendations are required on footing recommendations
Driveway) designs for the proposed retaining walls given the presence iv. Refer to Section 6.3 for footing
of loose to very loose sand. recommendations, and refer to Section 6 for
iv. The geotechnical design parameters to be adopted in the other design recommendations
design should be confirmed. Clear advice also needs to be
given in relation to accommodating other relevant site factors
into the design.”
10 “Provide full details as to how excavations on the site for the Refer to Sections 6.1 and 6.2 for excavation
(Retention proposed development layout are to be constructed and the support recommendations
Systems for retention systems to be employed to avoid causing instability
Excavations) both during and post construction.”
“Provide an independent slope stability assessment and This report provides geotechnical
geotechnical report for each of the proposed allotments. If recommendations and slope stability
13 appropriate, recommendations on measures to stabilise the assessment for Lots 1 to 3 as shown on the
land or maintain stability should be included.”
(Proposed Lots attached Figure 1. Lot 4 has been excluded
2, 3 and 4) from the currently proposed development
layout. Refer to Section 7 for slope stability
assessment and Sections 6 and 7 for
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Item Information Required Response
associated recommendations regarding
stabilisation of the site.
2.0 PROPOSED DEVELOPMENT
The current development layout comprises townhouses and an access driveway on Lot 1, and developments
on Lots 2 and 3, as shown on the attached Figure 1. The remainder of the site is dedicated open space.
3.0 SITE DESCRIPTION
The site (Lot 276 on RP 89506) covers about 1.8 hectares; and has frontage to Attunga Heights to the south
and is surrounded by residential development to the north, south and west.
The majority of the site comprises a sloping sand dune with an easterly to north-easterly aspect. A
meandering creek (tributary to Weyba Creek) runs south-to-north along the eastern boundary.
Ground slopes vary between about 20º to 27º, with steeper slopes of up to 40º to 45º adjacent to the creek
banks. Bedrock and boulders are exposed in the creek in some areas, along with colluvium
(cobbles/boulders in clay matrix)
At the time of our investigation, a two-storey residential dwelling with ancillary structures occupied the
southern part of the site. A concrete walkway is located along the western boundary of the site. The
remainder of the site was densely vegetated with medium to large shrubs and trees.
General ground surface contours and slope angles are shown on the attached Figure 1.
Photographs 1 and 2 show the general site conditions at the time of our investigation.
Photograph 1: Site conditions at the time of our investigation, looking approximately north from the existing
residence in the southern part of the site.
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Photograph 2: Site conditions at the time of our investigation, looking approximately south across the concrete
footpath on the western portion of proposed Lot 1.
4.0 METHOD OF INVESTIGATION
The investigation included the following:
A review of geological and landslide hazard overlay plans
A walk-over survey
Subsurface investigation and sampling at nine borehole locations
Seismic (MASW) testing along two lines (one 180 m line and two 30 m lines).
More detail on the investigation is provided in Sections 4.1 to 4.2 below.
4.1 Fieldwork – Boreholes
The subsurface investigation and walk-over survey was conducted on 11 and 12 April 2018. Prior to carrying
out the borehole drilling, a Dial Before You Dig (DBYD) search was carried out.
Nine boreholes (designated BH1 to BH9) were drilled using hand auger techniques to depths of between
0.7 m to 4 m below ground level (BGL). Dynamic cone penetrometer (DCP) testing was carried out adjacent
to the boreholes to help make an assessment of soil density/consistency.
The boreholes were drilled by a geotechnical engineer and engineering geologist from Core, who logged the
subsurface conditions in accordance with AS1726-2017 Geotechnical Site Investigations. Borehole locations
were recorded using a handheld GPS unit with a reported horizontal accuracy of ± 5 m.
The test locations are shown on the attached Figure 1. Reports of Boreholes are presented in Appendix A,
together with explanatory notes. The ground conditions are discussed in Section 5.2.
4.2 Fieldwork - MASW Seismic Testing
Seismic testing in the form of multi-channel analysis of surface waves (MASW) was undertaken along three
lines: Line 1 (180 m), Line 2 (30 m) and Line 3 (30 m) to an investigation depth of about 20 m BGL. The
alignments are shown on the attached Figure 1. The seismic survey equipment and data acquisition
parameters are summarised in Table 1.
The SurfSeis 2 software by Kansas Geological Survey (MASW) was used to process the field data.
Dispersion curves were obtained by selecting the peak amplitudes from the frequency-wavelength spectrum
in the fundamental mode. Inversion of the dispersion curves was then undertaken to estimate the strata vs
values.
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Table 2: Seismic Data Acquisition Parameters.
Seismic source: 10 kg sledgehammer on aluminium plate
Geode-24 seismograph using Geometrics Seismodule Controller
Recording system:
software; 24-bit 24-channel recorder
Recording channels: 24 per record
Sampling rate: 0.25 ms
Record length: 2 seconds
Geophone type: 4.5 Hz single geophones
Initial offset: 12 m
Source interval: 12 m
Geophone interval: 1.5 m
The MASW seismic testing method provides a subsurface profile of seismic surface shear-wave velocities
(vs). When correlated with the borehole/test pit findings, the seismic wave velocities can be used to provide
an indication of changes in the subsurface profile along the alignment tested.
Results of the seismic testing were correlated with the available geotechnical data, our previous experience,
and published information.
Seismic survey results are presented as 2D cross sections in Figure 2, with a discussion of the results given
in Section 5.2.
5.0 INVESTIGATION FINDINGS
5.1 Geological Mapping
The Gympie Special Geology map 1 indicates that the site is located close to the contact between the
Pleistocene age quartz sand and Jurassic to Cretaceous aged quartz diorite. Image 1 shows an extract from
the geology map.
1 GYMPIE SPECIAL 1:100,000 Geological Series. Map Sheet 9445 and Part 9545, First Edition, Department of Mines and Energy, Brisbane, 1999.
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Approximate site location
Qpd2
Image 1: Site geology as presented in the Gympie Special Geology Map1.
5.2 Ground Conditions
The subsurface conditions in the boreholes across proposed Lots 1 to 3 generally comprised:
Topsoil (sand) between 0.2 m and 0.3 m thick, overlying
Aeolian/Alluvial soil comprising about 1 m to 2 m of loose sand.
Stiff sandy clay (residual soil) was observed in borehole BH2 at 3.3 m depth. Very stiff sandy clay
(colluvium/residual soil) was also encountered at 1.4 m BGL in test pit TP10 in the 2003 investigation on
proposed Lot 3.
Inferred very loose or loose sands were typically encountered along the seismic lines to depths of about 1 m
to 2 m, up to about 3 m in some parts. The seismic testing indicates that soil density generally increases with
depth. Shear-wave velocities corresponding with weathered rock were encountered from about 12 m BGL
along Lines 1 and 2 (proposed Lot 1), and about 17 m depth at the higher elevation at Line 3 (proposed Lot
2).
Groundwater seepage was not encountered in any of the boreholes or test pits across proposed lots 1 to 3
6.0 GEOTECHNICAL DISCUSSION & RECOMMENDATIONS
6.1 Earthworks
6.1.1 Site preparation & trafficability
Site preparation in building and pavement areas should include the following:
Strip the surface of vegetation, organic matter, organic rich soils (topsoils), severely root affected soils,
and uncontrolled fill. Topsoil was generally encountered up to about 0.3 m, however it is anticipated that
grubbing of tree stumps and tree roots will require localised stripping to greater depths.
‘Proof roll’ the stripped surface by several passes of a minimum 10 tonne smooth-drum roller (without
vibration, to reduce slope stability impacts) to identify loose or soft areas. Proof rolling in areas of cut
may be deferred until after bulk excavation is completed.
Depressions formed during removal of large tree root systems should be backfilled with select fill and
compacted in layers in accordance with Section 6.1.3.
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Further recommendations regarding site preparation for fill earthworks are provided in Section 61.3.
A working platform assessment must be carried out by a suitably qualified person (RPEQ) for heavy
machinery or equipment (e.g. crane or piling rig).
6.1.2 Excavations
Investigation results indicate that the proposed excavations should be achievable using conventional
earthmoving equipment. Ripping may be encountered where colluvium is encountered (e.g. proposed Lot 3).
Horizontal direction drilling (HDD) for underground services must consider the presence of colluvium
containing boulders.
6.1.3 Filling
Fill must not be placed on slopes exceeding 15o or on slopes within about 20 m of the creek, unless fully
supported by engineer-designed retaining structures (refer Section 6.2).
For the access driveway, the retaining structures must be constructed prior to placing fill. Compaction of fill
must be done without the use of vibration, to reduce possible impacts on slope stability. Careful attention
must be paid to moisture conditioning of fill during placement. It should be noted that settlement of the very
loose sand subgrade will likely occur immediately following fill placement.
Fill should be compacted at moisture contents within the range of -/+ 2% of optimum moisture content for
Standard Compaction. Confirmatory testing must be carried out at regular intervals. A minimum of two tests
per 300 mm vertical interval 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 should have a maximum particle size of 100 mm for an
uncompacted layer thickness of 200 mm and shall be compacted by repeated rolling to achieve a dry density
ratio of at least 98% of the Maximum Standard Dry Density for cohesive soils, or 75% Dry Density Index for
cohesionless soils.
In accordance with good construction practice, fill embankments should be ‘benched’ into slopes following
stripping and ‘over built’ then trimmed back to the well compacted material.
It is recommended that filling be carried out to Level 1 standards in accordance with AS3798-2007.
6.1.4 Batter slopes
Unsurcharged cut batters in medium dense (or denser) sand and stiff clay up to 3 m vertical height should
not be formed steeper than 1V:2H. Flatter batters may be required if groundwater is encountered during
construction. Batter slopes in very loose/loose sands may be formed at 1V:3H.
Cut batters must be assessed by a geotechnical engineer from Core during excavation. Such assessments
should be undertaken progressively, with excavated face heights prior to assessment being limited to 1.5 m.
Cut batters will require re-vegetation to prevent erosion. This may require the use of hydromulching or
geotextiles to promote vegetation growth.
Positive support by engineer designed retained structures (refer Section 6.2) will be required where space
restrictions prevent trimming of batters to safe slopes, where slopes are surcharged or near movement
sensitive structures.
6.1.5 Excavation support
Steeper slopes than those recommended in Section 6.1.4 will require excavation support. Options for
support include the following:
Contiguous continuous flight auger (CFA) piles with infill grouting of voids
Micropile A-frame structure
The use of sheet piles or driven ‘H’ sections may lead to stability impacts due to vibration during installation.
Detailed design for excavation support should be undertaken when the bulk earthworks have been confirmed
and the preferred method of excavation support selected. The detailed design must consider slope stability
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and suitable founding materials. It is our opinion that an appropriately designed micropile or CFA pile
structure will provide acceptable factors of safety against global slope instability.
It is understood that underground services will be installed via HDD. Unsupported open trenching for the
installation of services should not be undertaken.
6.2 Retaining Wall Design and Parameters
Retaining walls must be founded as described in Section 6.3 and may be designed using the parameters in
Table 3, and in accordance with AS4678-2002 Earth retaining structures.
Allowance should be made for construction loading, up-slope footing loadings, the effects of sloping ground
(if not supported on piles), hydrostatic loads, and backfill compaction stresses.
Table 3: Retaining Structure Design Parameters.
Unit Friction
Lateral Earth Pressure Coefficient
Weight Angle
Retained Material Ka Ko
(t/m3) (Degrees) (Cantilever (Non yielding Kp
Wall) wall)
Loose Sand 1.7 30 0.3 0.5 3.0
Medium Dense Sand 1.8 34 0.25 0.45 3.4
Dense sand 1.9 38 0.2 0.4 4.2
Stiff (or stiffer) Clay 1.8 27 0.4 0.6 2.6
Engineered Fill (future) 1.9* 34* 0.28* 0.4* 3.5*
Note: *Preliminary only; depends on fill material type and level of compaction.
Positive permanent drainage must be installed behind all walls unless they are designed for development of
full hydrostatic pressures.
6.3 Foundation Design and Parameters
6.3.1 High-level footings
Where suitable stiff (or stiffer) clay is present at shallow depth (i.e. proposed Lot 3), the proposed buildings
may be supported on conventional high-level strip or pad footings. Such footings may be designed using an
allowable bearing pressure of 100 kPa.
To achieve the design recommended pressures, footing excavations must be dry and cleaned of any loose,
disturbed or saturated materials prior to pouring concrete.
All existing and proposed 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 building or fill loads.
To minimise the potential for any adverse interaction effects, footings should found at least below a plane
extending 1 m horizontally from the base of trenches/batter slopes/excavations/ retaining walls, then rising
up at 1V:1H. This requirement is illustrated in the following diagram.
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6.3.2 Piles
Where loose sand is present (i.e. Proposed lots 1 and 2), structures should be supported on the underlying
medium dense (or denser) sand. Grout-injected CFA or bored piles are considered suitable. Bored piles may
encounter significant fall-in of loose sand unless a casing/liner is used during construction.
Drilling spoil or fluid should not be stockpiled or discharged on site.
Table 4 shows representative values of ultimate (unfactored) geotechnical parameters for bored/CFA pile
design. A sensitivity analysis should be undertaken to assess effects for the range of parameters.
Table 4: Pile Design Parameters.
Ultimate skin Ultimate base
Material type
friction (kPa) resistance (kPa)
Loose sand 10 NR
Medium dense sand 20 NR
Dense sand 40 NR
Very dense sand 60 1800
Stiff clay 30 500
Very stiff or hard clay 50 1300
Low strength (or
100 2200
stronger) rock
Notes:
1) NR – Not recommended
2) Skin friction should be discounted for sections of pile shafts where liners are in place
Piles should be designed to resist lateral loads from the movement of loose sand, in the event of localised
slope instability. Lateral forces should be estimated on the assumption that lateral movement occurs along
the interface between loose and medium dense sand, using an assumed depth of 3 m. Calculation of lateral
forces on piles may be carried out in accordance with the method outlined below:
Ultimate geotechnical capacities (Rd,ug) determined from the parameters provided must be multiplied by a
geotechnical strength reduction factor (øgb) in accordance with Section 4 of AS 2159-2009 Piling – Design
and installation to determine the design geotechnical strength (Rd,g). The geotechnical strength reduction
factor should be determined in accordance with AS 2159-2009 and is expected to be in the range of 0.45 to
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0.55. An upper bound value may be adopted if supervision and certification of pile construction is carried out
by a geotechnical engineer.
Specialist piling contractors should be consulted with respect to selection of suitable pile types, detailed
design of piles, and pile testing. Detailed design of pile foundations should include geotechnical modelling
using, for example, Plaxis software.
6.4 Drainage & Erosion Control
Site drainage should be designed to readily remove surface water and to prevent ponding of water.
Stormwater should be piped to an engineer-designed dissipation system in the creek. Concentrated surface
water flows (e.g. roof runoff) should be avoided.
Vegetation disturbance should be minimised, and unprotected ground surfaces protected from erosion by
matting and/or revegetation. Vegetation along the creek banks must be maintained, and revegetation
undertaken in sparsely vegetated parts.
Creek bank stabilisation should be considered as part of the civil design (e.g. gabion baskets, drainage, use
of matting or ‘Geo-cell’ products).
7.0 SLOPE STABILITY ASSESSMENT & RECOMMENDATIONS
The Noosa Council (NC) Landslide and Flooding Overlay mapping indicates that parts of the site are in a
landslide hazard area. Image 2 presents an extract of the NC Landslide and Flooding Overlay Map for the
site.
Location of subject site
Image 2: Extract from NC Landslide and Flooding Overlay Map.
Based on the investigation results and previous stability modelling (03632248-001), the natural slopes are
considered to be close to equilibrium (i.e. factor of safety just above 1) for translational failures through the
surficial loose sands. The existing vegetation is contributing to natural stability of the slope through surface
protection and the stabilising effect of root systems.
The overall approach to managing slope stability for the proposed development should be to have a ‘non-
worsening’ impact on slope stability. The recommendations regarding footings, earthworks and drainage
provided in this report are made accordingly.
In addition, it is important that vegetation disturbance outside the building/pavement footprints is kept to a
minimum, and that suitable erosion protection is provided where vegetation is not present (e.g. matting
and/or revegetation). Temporary or permanent soil surface stabilisation in the form of cellular confinement
systems (e.g. ‘geo-cells’ or ‘geoweb’) could be undertaken in conjunction with revegetation.
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7.1 Qualitative Slope Stability Assessment
A qualitative slope stability risk assessment for this project has been carried out following the Australian
Geomechanics Society (AGS) Guidelines for Landslide Risk Management (March 2007). The risk
assessment relates to property. Relative levels of risk and their implications are given in Table 5 below and
the qualitative terminology (i.e. likelihood and consequence definitions) for use in assessing risk to property
are attached in Appendix D. Our risk assessment is summarised in Table 6.
Table 5: Stability Risk Levels.
Risk Level Example Implications(1)
Unacceptable without treatment. Extensive detailed investigation and research,
VERY HIGH planning and implementation of treatment options essential to reduce risk to Low;
VH
RISK may be too expensive and not practical. Work likely to cost more than value of
property.
Unacceptable without treatment. Detailed investigation, planning and implementation
H HIGH RISK of 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
MODERATE requires investigation, planning and implementation of treatment options to reduce
M
RISK risk to Low. Treatment options to reduce to Low risk should be implemented as soon
as practicable.
L LOW RISK Usually acceptable to regulators. Where treatment has been required to reduce the
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.
Table 6: Qualitative Risk Assessment for Property (Based on AGS 2007).
Assessed
Hazard Likelihood Consequence Comments
Risk
Shallow translational failure in the loose sands
Shallow failure of is considered Possible, but if the
soils above the recommendations in this report are
Possible Insignificant Very Low
footing zone (< 3m implemented, the consequence to property is
depth) assessed as Insignificant. The resulting
assessed risk is Very Low.
The likelihood of a deep failure through the
dense (or denser) sand or stiff (or stiffer)
colluvium/residual soil is assessed as Rare
Deeper failure
based on the results of the 2003 slope stability
through soils below Rare Major Low
modelling (03632248-001) and the slope
footing depth
profile. Although the consequence of such a
failure would likely be Major, the resultant risk
is Low.
Refer Appendix C, Qualitative Risk Analysis Matrix (Australian Geomechanics Vol 42 No 1 March 2007).
Based on the available information and the results of the investigation, it is our opinion that there is a Low to
Very Low Risk of slope instability for the proposed development assessed in accordance with the AGS
guidelines (March 2007).
7.2 Slope Stability Modelling
Slope stability modelling of the proposed access driveway fill and retaining structure was carried out using
Geostudio’s Slope/W software.
The model section was based on an assumed ‘worse case’ profile (i.e. deepest fill and steepest slope), from
the Preliminary Engineering Report (C5756/17/ENG Rev A) by Walsh Professional Engineers.
Groundwater was only encountered in test pit TP5 (2003) at the interface between the soil and rock (outside
the currently proposed development layout area). No groundwater was encountered in the other test pits or
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boreholes. Given the permeable nature of the sands it is unlikely that a permanent water table will occur.
However, for a short-term case, a groundwater level was assumed at the top of the dense sands.
Soil parameters assumed for the modelling were based on the available geotechnical information, and Table
D4 of AS 4678-2002 Appendix 4 Soil and Material Properties.
Results and details of the stability modelling are shown on the attached Figure 3.
The modelling indicates that the proposed fill and retaining structures have acceptable factors of safety,
provided that the retaining structures are founded in the dense sand or stronger materials.
8.0 LIMITATIONS
Your attention is drawn to the document, Limitations which is attached in Appendix C.
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J000635-002-R-Rev1 November 2018 Core Consultants Pty Ltd Yours sincerely, CORE CONSULTANTS PTY LTD Walter Mastenbroek Geoff Hurley MEngPr MSc BSc (Hons) PMP NER CPEng RPEQ MSc DIC C.Geol RPEQ5716 Associate/Senior Geotechnical Engineer Director BH/WM/GAH/bh/wm
Page 16
#### BH2
BH1
o
45
TP10
BH7/7A
BH6 TP6
L2
F002
20-25o
BH7
BH4/4A BH5
TP5
BH6
BH3
20-25o
BH5
BH8
TP8
Plot Date: 1 November 2018 Time:10:47:06 AM By: CAD Path: J:\2018 - J579 -\J000635 - IPS-Development-Attunga Heights\PHASE 1000\Figures Drawings\Working copies - File Name:J000635-001-R-Rev0-F001.dwg
BH2
BH1 o TP9
27
L1
F002
L1
F002
BH8
BH4
o
L2 27
F002
BH1
L3
F002
BH3 BH2/2A
L3
F002
BH9
0 16 32 48 m
1:800
LEGEND CLIENT PROJECT
LINE 1 LINE 1 NOVATO GROUP C/- IPS PTY LTD PROPOSED DEVELOPMENT, 27 ATTUNGA HEIGHTS, NOOSA HEADS
F002 F002
DRAWN BY DATE DRAWING TITLE
Indicative MASW line location and drawing reference
BH9 BH 01/11/2018
Indicative borehole location (Core Consultants 2018)
BH2
Indicative borehole location (Core Consultants 2017)
CHECKED BY DATE SITE PLAN
BH1 WM 01/11/2018
Indicative test pit or borehole location (Golder Associates 2003)
SCALE SHEET SIZE PROJECT No DOC No DOC TYPE FIGURE No REVISION
BASE PLAN FROM TIM DITCHFIELD ARCHITECTS. DRG. No. DD 02-P2. DATED SEPTEMBER 2018. www.coreconsultants.com.au 1:800 A3 J000635 002 R F001 0 SHEET 1 OF 1
C CORE CONSULTANTS PTY. LTD. INFORMATION CONTAINED ON THIS DRAWING IS THE COPYRIGHT OF CORE CONSULTANTS PTY. LTD. UNAUTHORISED USE OR REPRODUCTION OF THIS PLAN EITHER WHOLLY OR IN PART WITHOUT WRITTEN PERMISSION INFRINGES COPYRIGHT.
Page 17
COMMENTS:
• Results of the seismic testing generally correlates with the borehole results.
• Inferred very loose or loose sands were typically encountered along the seismic lines to
depths of about 1 m to 2 m, up to about 3 m in some parts. The seismic testing indicates
that soil density generally increases with depth.
• Shear-wave velocities corresponding with weathered rock were encountered from about
12 m BGL along Lines 1 and 2 (proposed Lot 1), and about 17 m depth at the higher
elevation at Line 3 (proposed Lot 2).
NOTES:
Refer to Drawing J000635-002-R-Rev0-Figure 1 for section alignments.
This document must be read in conjunction with report J000635-002-R-Rev0.
CLIENT PROJECT
NOVATO GROUP 27 ATTUNGA HEIGHTS, NOOA HEADS
DRAWN DATE TITLE
BH 8/05/2018
CHECKED DATE SEISMIC (MASW) TESTING
WM 8/05/2018
SCALE PROJECT No FIGURE No REV No
AS SHOWN J000635 002 0 A3
Page 18
Long-term case
1.9
1.9
60
Name: SAND (FILL)
58 Unit Weight: 18 kN/m³
Cohesion': 8 kPa
56 Phi': 34 °
54
Name: SAND (TOPSOIL)
52 Unit Weight: 16 kN/m³
Retaining Wall Cohesion': 1 kPa
50 Phi': 27 °
48
Name: Loose SAND (AEOLIAN/ALLUVIAL SOIL)
Elevation (m)
46 Unit Weight: 17 kN/m³
Cohesion': 0 kPa
44 Phi': 27 °
42
Name: Medium Dense SAND (AEOLIAN/ALLUVIAL SOIL)
Unit Weight: 18 kN/m³
40
Cohesion': 4 kPa
Phi': 34 °
38
36
Name: Dense SAND (AEOLIAN/ALLUVIAL SOIL)
34 Unit Weight: 19 kN/m³
Cohesion': 8 kPa
Information contained on this drawing is the copyright of Core Consultants Pty Ltd. Unauthorised use or reproduction of this plan either wholly or in part without written permission infringes copyright. © Core Consultants Pty Ltd.
32 Phi': 38 °
30
Name: Diorite (ROCK)
28 Unit Weight: 20 kN/m³
Cohesion': 20 kPa
26 Phi': 39 °
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Distance (m)
Short-term case
1.6
1.6
60
Name: SAND (FILL)
58 Unit Weight: 18 kN/m³
Cohesion': 8 kPa
56 Phi': 34 °
54
Name: SAND (TOPSOIL)
52 Unit Weight: 16 kN/m³
Cohesion': 1 kPa
50 Retaining Wall Phi': 27 °
48
Name: Loose SAND (AEOLIAN/ALLUVIAL SOIL)
Elevation (m)
46 Unit Weight: 17 kN/m³
Cohesion': 0 kPa
44 Phi': 27 °
42
Name: Medium Dense SAND (AEOLIAN/ALLUVIAL SOIL)
Unit Weight: 18 kN/m³
40
Cohesion': 4 kPa
Phi': 34 °
38
36
Name: Dense SAND (AEOLIAN/ALLUVIAL SOIL)
34 Unit Weight: 19 kN/m³
Cohesion': 8 kPa
32 Phi': 38 °
30
Name: Diorite (ROCK)
28 Unit Weight: 20 kN/m³
Cohesion': 20 kPa
26 Phi': 39 °
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Distance (m)
CLIENT PROJECT
Innovative Planning Solutions Proposed Development – Attunga Heights
DRAWN DATE TITLE
OS 09/05/2018
CHECKED DATE
Retaining Wall Slope Stability Analysis
WM 09/05/2018
SCALE PROJECT No FIGURE No REV No
www.coreconsult.com.au As shown J000635 3 0 A3
TMP-014 Site Plan 28/10/2015 Ver. 1.01
Page 19
J000635-002-R-Rev1 November 2018 APPENDIX A Reports of Boreholes and Explanatory Notes
Page 20
REPORT OF BOREHOLE: BH1
EAST: 509210.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7081144.0 m LOGGED: BH/MC
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 11/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, pale grey and brown, trace fines,
trace rootlets
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, brown, trace
fines, trace rootlets
HA
L D L
0.70
END OF [email protected] m
REFUSAL ON TREE ROOTS
BACKFILLED
1
2
>20
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
4
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 21
REPORT OF BOREHOLE: BH2
EAST: 509187.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7081147.0 m LOGGED: BH/MC
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 11/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, pale grey and brown, trace HW
rootlets
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, pale brown and
pale grey
L
1
L D
D
2.00
HA
2
2.10 Dark brown, with clay to 2.1 m depth
Pale grey
MD
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3 VD
3.20
3.30 SC CLAYEY SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, dark
CL brown, low plasticity clay VSt
SANDY CLAY (RESIDUAL SOIL): low plasticity, orange brown
3.50 and brown, fine grained sand
Orange brown and grey
W
M-H
(=PL)
St
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 22
REPORT OF BOREHOLE: BH3
EAST: 509154.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7080908.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, brown and pale grey, trace
rootlets D
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, brown and pale
brown, trace rootlets L
0.80
Pale grey, trace roots and rootlets
1.00
1
Pale grey and brown MD
1.20
Pale grey
HA
L 2
M
D
2.50
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Pale grey with mottled grey
Not Encountered
3
VD
3.70
Pale grey and brown
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 23
REPORT OF BOREHOLE: BH4
EAST: 509149.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7080933.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, grey and brown, trace silt, trace HW
rootlets
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, dark brown,
trace silt, trace rootlets
L
1
1.10
Pale brown
MD
1.50
Pale grey
HA
L 2 D
D
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
VD
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 24
REPORT OF BOREHOLE: BH5
EAST: 509156.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7081030.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, grey and brown, trace rootlets HW
0.30
L
SM SILTY SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, brown,
trace rootlets
0.90
Pale brown
1
MD
1.30
Pale grey
HA
L 2 D
D
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
VD
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 25
REPORT OF BOREHOLE: BH6
EAST: 509149.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7080934.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, brown and grey, with rootlets HW
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, grey and pale
grey
0.60 L
Dark brown
1.00
1
Pale grey and brown
D
HA
L 2 D
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
VD
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 26
REPORT OF BOREHOLE: BH7
EAST: 509164.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7081083.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, pale brown, trace rootlets HW
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, dark brown,
trace rootlets
L
1
1.10
Pale grey
HA
L 2 D
MD -
D
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
VD
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 27
REPORT OF BOREHOLE: BH8
EAST: 509160.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7080960.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (TOPSOIL): fine grained, dark brown and grey, trace silt, HW
trace rootlets
0.30
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, dark grey, trace
silt
0.80 L
Pale grey
1
MD
HA
L 2 D
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3 D
VD
4.00
4
END OF [email protected] m
TARGET DEPTH
BACKFILLED
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 28
REPORT OF BOREHOLE: BH9
EAST: 509146.0 m SHEET 1 OF 1
CLIENT: David Neate C/- Innovative Planning Solutions NORTH: 7080895.0 m LOGGED: MC/OS
PROJECT: Proposed Development CONTRACTOR: Core Consultants LOGGED DATE: 12/04/18
LOCATION: 27 Attunga Heights, Noosa Heads DRILL RIG: Hand Auger CHECKED: WM
JOB NO: J000635 INCLINATION: -90° CHECKED DATE: 08/05/18
Drilling Sampling Field Material Description
CONSISTENCY
USCS SYMBOL
PENETRATION
DCP TEST
RECOVERED
RESISTANCE
CONDITION
MOISTURE
SAMPLE OR (AS 1289.6.3.2-1997)
GRAPHIC
DENSITY
METHOD
SOIL/ROCK MATERIAL DESCRIPTION Blows per 100 mm
(metres)
FIELD TEST
WATER
DEPTH
LOG
DEPTH 0 5 10 15 20 25
RL
0
SP SAND (FILL): fine grained, dark brown and dark grey, with gravel,
trace roots
0.20
SP SAND (AEOLIAN/ALLUVIAL SOIL): fine grained, dark brown,
trace gravel, trace rootlets
0.50
Grey and brown, trace gravel
HA
L L
1
1.50
END OF [email protected] m
HOLE COLLAPSING
BACKFILLED
2
CORE 1.00 LIB.GLB Log IS AU BOREHOLE 3 J000635 BHS.GPJ <<DrawingFile>> 08/05/2018 17:09 10.0.000 Datgel Fence and Map Tool | Lib: DGDT-P 3.05.0 2016-01-20 Prj: DGDT-P 3.05.0 2016-01-20
Not Encountered
3
4
5
6
This report must be read in conjunction with accompanying notes and abbreviations. It has been prepared for geotechnical
purposes only, without attempt to assess possible contamination. Any references to potential contamination are for information
only and do not necessarily indicate the presence or absence of soil or groundwater contamination.
Page 29
EXPLANATION OF NOTES, ABBREVIATIONS & TERMS
USED ON BOREHOLE AND TEST PIT REPORTS
DRILLING/EXCAVATION METHOD
AS Auger Screwing RD Rotary blade or drag bit NQ Diamond Core - 47 mm
AD Auger Drilling RT Rotary Tricone bit NMLC Diamond Core - 52 mm
*V V - Bit RAB Rotary Air Blast HQ Diamond Core - 63 mm
T TC - Bit, e.g. ADT RC Reverse Circulation HMLC Diamond Core – 63mm
HA Hand Auger PT Push Tube BH Tractor Mounted Backhoe
ADH Hollow Auger CT Cable Tool Rig EX Tracked Hydraulic Excavator
DTC Diatubre Coring JET Jetting EE Existing Excavation
WB Washbore or Bailer NDD Non-destructive digging HAND Excavated by Hand Methods
PENETRATION/EXCAVATION RESISTANCE
L Low resistance . Rapid penetration possible with little effort from the equipment used
M Medium resistance. Excavation possible at an acceptable rate with moderate effort from equipment used
H High resistance to penetration/excavation. Further penetration is possible at a slow rate
R Refusal or Practical Refusal. No further progress possible without the risk of damage or unacceptable wear to the digging implement
These assessments are subjective and are dependent on many factors including the equipment power, weight, condition of excavation or drilling tools,
and the experience of the operator.
WATER
Water level shown at date Partial water loss
Water inflow Complete water loss
GROUNDWATER NOT The observation of groundwater whether present or not, was not possible due to drilling water, surface seepage or cave in
OBSERVED of the borehole/test pit.
GROUND WATER NOT The borehole/test pit was dry soon after excavation. However, groundwater could be present in less permeable strata.
ENCOUNTERED 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
4,7,11 N=18 4,7,11 = Blows per 150mm N = Blows per 300mm penetration following 150mm seating
30/80mm 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
G Gas Sample
W Water sample
FP Field permeability test over section noted
FV Field vane shear test expressed as uncorrected shear strength (sv = peak value)
PID Photoionisation Detector reading in ppm
PM Pressuremeter test over section noted
PP Pocket penetrometer test expressed as instrument reading in kPa
U63 Thin walled tube sample - number indicates nominal sample diameter in millimetres
WPT Water pressure tests
DCP Dynamic cone penetration test
CPT Dynamic cone penetration test
CPTu Static cone penetration test with pore pressure (u) measurement
ROCK CORE RECOVERY
TCR = Total Core Recovery (%) SCR = Solid Core Recovery (%) RQD = Rock Quantity Designation (%)
Explanation of Notes, Abbreviations & Terms Used on Borehole and Test Pit Reports Date: 12/07/2018
FRM-068
Ver. 1.03
Page 30
METHOD OF SOIL DESCRIPTION USED ON BOREHOLE AND TEST PIT
REPORTS
FILL CLAY (CL,CI, or CH)
GRAVEL (GP or SW) ORGANIC SOILS (OL or OH or Pt)
SAND (SP or SW) COBBLES or BOULDERS
SILT (ML or MH)
Combinations of these basic symbols may be used to indicate mixed materials such as sandy clay.
CLASSIFICATION AND INFERRED STRATIGRAPHY
Soil and Rock is classified and described in Reports of Boreholes and Test Pits using the preferred method given in AS 1726 - 2017. The material proper-
PARTICLE SIZE PLASTIC PROPERTIES
Major
Sub Division Particle Size
Division
Boulders >200 mm
Cobbles 63 - 200 mm
Gravel Coarse 20 - 63 mm
Gravel Medium 6.7 - 20 mm
Gravel Fine 2.36 - 6.7 mm
Sand Coarse 0.6 - 2.36 mm
Sand Medium 0.21 - 0.6 mm
Sand Fine 0.075 - 0.21 mm
Silt 0.002 - 0.075 mm
Clay <0.002 mm
MOISTURE CONDITION FOR COARSE GRAINED SOIL AS 1726 - 2017
Symbol Term Description
D Dry Non-cohesive and free running
M Moist Soil feels cool, darkened in colour, tends to stick together
W Wet Soil feels cool, darkened in colour, soil sticks together, free water forms when handling
MOISTURE CONDITION FOR FINE GRAINED SOIL AS1726 - 2017
Symbol Term Description
W<PL Moist dry of liquid limit Hard and friable or powdery
W = PL Moist near plastic limit Soils can be molded at a moisture condition approximately equal to the plastic limit
W >PL Moist, wet of plastic limit Soils usually weakened and free water forms on hands when handling
W = LL Wet near plastic limit
W > LL Wet, wet of liquid limit
CONSISTENCY TERMS FOR AS1726—2017 RELATIVE DENSITY OF COARSE GRAINED SOILS AS1726—2017
COHESIVE SOILS
Symbol Term Density Index % SPT ‘N’ #
Symbol Term Undrained Shear
VL Very Loose Less than 15 0 to 4
Strength
L Loose 15 to 35 4 to 10
VS Very Soft 0 to 12 kPa
S Soft 12 to 25 kPa MD Medium Dense 35 to 65 10 to 30
F Firm 25 to 50 kPa D Dense 65 to 85 30 to 50
St Stiff 50 to 100 kPa VD Very Dense Above 85 Above 50
VSt Very Stiff 100 to 200 kPa In the absence of test results, consistency and density may be assessed from correlations with
the observed behaviour of the material.
H Hard Above 200 kPa
Explanation of Notes, Abbreviations & Terms Used on Borehole and Test Pit Reports Date: 12/07/2018
FRM-068
Ver. 1.03
Page 31
TERMS FOR ROCK MATERIAL STRENGTH & WEATHERING AND
ABBREVIATIONS FOR DEFECT DESCRIPTIONS
ROCK MATERIAL STRENGTH CLASSIFICATION AS1726—2017
Symbol Term Uniaxial Point Load Field Guide
Compressive Strength Is (50)
Strength (MPa) (MPa)
VL Very Low 0.6 to 2 0.03 to 0.1 Material crumbles under firm blows with sharp end of pick. Pieces up to 30 mm thick can
Strength be broken with finger pressure.
L Low Strength 2 to 6 0.1 to 0.3 Easily scored with knife. Indentations 1 mm to 3 mm show in the specimen with firm
blows of the pick point. A piece of core 150 mm by 50 mm may be broken by hand. Sharp
edges of core are friable and break during handling.
M Medium 6 to 20 0.3 to 1 Readily scored with a knife. A piece of core 150 mm by 50 mm can be broken by hand
Strength with difficulty.
H High Strength 20 to 60 1 to 3 A piece of core 150 mm by 50 mm cannot be broken by hand but can be broken by a pick
with a single firm blow. Rock rings under hammer.
VH Very High 60 to 200 3 to 10 Hand specimen breaks with pick after more than one blow. Rock rings under hammer.
Strength
EH Extremely High Above 200 Above 10 Specimen requires many blows with geological pick to break through intact material. Rock
Strength rings under hammer.
= Diametral Point Load Test = Axial Point Load Test
CLASSIFICATION OF MATERIAL AS1726—2017
WEATHERING
Symbol Term Field Guide
RS Residual Soil (Note 1) Material is weathered to such an extent that it has soil properties. Mass structure and material texture and
fabric of original rock are no longer visible but the soil has not been significantly transported.
XW Extremely Weathered Material is weathered to such an extent that is has soil properties. Mass structure and material texture and
(Note 1) fabric of original rock are still visible.
HW Highly Weathered (Note 2) The whole rock mass is discoloured, usually by iron staining or beaching to the extent that the colour of the
original rock is not recognizable. Rock strength is significantly changed by weathering. Some primary miner-
als have weathered to clay minerals. Porosity may be increased by leaching, or may be decreased due to
deposition of weathering products in pores.
MH Moderately Weathered The whole of the rock material is discoloured, usually by iron staining or bleaching to the extent that the
(Note 2) colour of the original rock is not recognizable, but shows little or no change in strength from fresh rock.
SW Slightly Weathered Pock is partially discoloured with staining or bleaching along joints but shows little or no change of strength
from fresh rock.
FR Fresh Rock shows no signs of decomposition of individual minerals or colour change.
Note 1 The term ‘Extremely Weathered rock’ is misleading as the material has soil properties. The word ‘rock’ should be replaced with the name
of the original rock of the word ‘material’, eg. Extremely Weathered granite or Extremely Weathered material.
Note 2 Where it is not possible to distinguish between ‘Highly Weathered’ and ‘Moderately Weathered’ rock the term ‘Distinctly Weathered’ may
be used.
DEFECT TYPE/DESCRIPTION DEFECT PROFILE DEFECT ROUGHNESS
Symbol Description DESCRIPTION
B Bedding Parting V Vein
PL Planar
Symbol Description
J Joint HB/DB Handling/Drilling St Stepped
Break Sl Slickenside
Un Undulating
EW Extremely Weathered C Contact Sm Smooth
DEFECT INFILL DESCRIPTION
Seam
Ro Rough
Symbol Description
FZ Fracture Zone L Cleavage Vertical Boreholes - The dip
Cn Clean: No visible
coating (inclination from horizontal) for the
CZ/S Crushed Zone/Seam X Foliation defect is given.
Sn Stain: Coated 1 to
3 mm Inclined Boreholes - The inclination
IS Infilled Seam S Schistocity is measured as the acute angle to the
Vr Veneer: < 1 mm core axis.
SZ/S Sheared Zone/Seam Ct Coating: 1 to 3
mm
Terms for Rock Material Strength and Weathering & Abbreviations for Defect Descriptions Date: 17/10/2018
FRM-069 Ver. 1.04
Page 32
J000635-002-R-Rev1 November 2018 APPENDIX B AGS Practice Note Guidelines for Landslide Risk Management
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
91 Australian Geomechanics Vol 42 No 1 March 2007
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.
92 Australian Geomechanics Vol 42 No 1 March 2007
Page 35
J000635-002-R-Rev1 November 2018 APPENDIX C Limitations
Page 36
LIMITATIONS This Document has been provided by Core Consultants Pty Ltd (“Core”) subject to the following limitations: This Document has been prepared for the particular purpose outlined in Core’s proposal and no responsibility is accepted for the use of this Document, in whole or in part, in other contexts or for any other purpose. The scope and the period of Core’s Services are as described in C o r e ’s proposal, and are subject to restrictions and limitations. Core did not perform a complete assessment of all possible conditions or circumstances that may exist at the site referenced in the Document. 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 Core in regards to it. Conditions may exist which were undetectable given the limited nature of the enquiry Core was retained to undertake with respect to the site. Variations in conditions may occur between investigatory 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. Accordingly, additional studies and actions may be required. In addition, it is recognised that the passage of time affects the information and assessment provided in this Document. Core’s opinions are based upon information that existed at the time of the production of the Document. It is understood that the Services provided allowed Core to form no more than 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 this Document are based on the conditions indicated from published sources and the investigation described. 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 Core for incomplete or inaccurate data supplied by others. Core may have retained subconsultants affiliated with Core to provide Services for the benefit of Core. To the maximum extent allowed by law, the Client acknowledges and agrees it will not have any direct legal recourse to, and waives any claim, demand, or cause of action against, Core’s affiliated companies, and their employees, officers and directors. This Document is provided for sole use by the Client and is confidential to it 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. Core accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this Document. Limitations Page 1 of 1 Date: 12/07/2018 FRM-065 Uncontrolled When Printed Issue: 1.02
Page 37
@ Environmental iB Geotechnical 3) Project Management www.coreconsultants.com.au Sunshine Coast 52 Second Avenue, Maroochydore Qid 4558 T 07 5475 5900 E [email protected] Gold Coast 36 Kuranga Avenue, Southport Qld 4215 T 07 5503 1943 ABN 75 603 384 050
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