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Slope Stability Report · EXE22/0013
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SLOPE STABILITY RISK
ASSESSMENT REPORT
Site Address: Lot 35 on RP203515 (No.285)
David Low Way, Peregian Beach Qld 4573
Client: Brisbane Construction Group Pty Ltd
Project Job No. GEO205860‐B
Date: 1st of June, 2022
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Section 2
TABLE OF CONTENTS 1.0 INTRODUCTION 2.0 SCOPE AND METHOD OF INVESTIGATIONS 2.1 Qualifications of Responsible Firm ................................................................................................. 3.0 PROPOSED DEVELOPMENT 4.0 OVERVIEW 4.1 Regional Setting and Site Description ............................................................................................. 4.2 Regional Geology ............................................................................................................................ 5.0 GEOTECHNICAL SITE INVESTIGATION 5.1 Fieldwork......................................................................................................................................... 5.2 Subsurface Conditions .................................................................................................................... 5.3 Groundwater ................................................................................................................................... 6.0 SLOPE STABILITY ASSESSMENT 6.1 Stability Assessment Findings ......................................................................................................... 6.2 Desktop Assessment Findings ......................................................................................................... 6.3 Hazard Identification ....................................................................................................................... 6.4 Qualitative Risk Assessment ........................................................................................................... 7.0 COMMENT & RECOMMENDATIONS 7.1 Development................................................................................................................................... 7.2 Development Constraints ............................................................................................................... 7.3 Earthworks ...................................................................................................................................... 7.4 Foundations .................................................................................................................................... 7.5 Drainage .......................................................................................................................................... 7.6 Erosion Control & Landscape .......................................................................................................... 8.0 COMPLIANCE CERTIFICATION 9.0 CONCLUSION APPENDICES Appendix A – Soil Profiles and Laboratory Results Appendix B – Landslide Frequency Analysis Appendix C – Site Photographs Appendix D – Site Maps Appendix E – Qualitative Terminology for use in assessing risk to property Appendix F – Stability of Retaining Structures Appendix G – Hillside Construction
Section 3
1.0 INTRODUCTION
This report presents the results of a geotechnical walk over assessment of stability investigation
carried out by STA Consulting Engineers at Lot 35 on RP203515 (No.285) David Low Way, Peregian
Beach Qld 4573.
2.0 SCOPE AND METHOD OF INVESTIGATIONS
The aim of this report is to assess the potential risk of slope instability or Landslide risk for the
proposed residential development in its existing and post developed state.
It must be noted that this report reflects the results of a qualitative risk assessment only and is not
to be seen as a slope stability analysis or design report, nor is it intended to quantify a geotechnical
factor of safety or certify the design as provided by the client.
The methodology adopted by STA Consulting Engineers in order to determine the Landslide risk for
this site is obtained incorporating the following criteria :‐
Guidelines developed by the Australian Geomechanics Society (AGS), Landslide Risk
Management, Volume 42 No.1, March 2007.
Landslide Frequency Assessment in accordance with the report “A Method of Zoning
Landslide Hazards”, prepared by MacGregor and Taylor 2001.
A review of existing Hazard mapping (where available), aerial photographs and various
published information to assist in identifying past activity.
2.1 Qualifications of Responsible Firm
This report is prepared by a Registered Professional Engineer of Queensland (RPEQ) specialising in
geotechnical engineering.
3.0 PROPOSED DEVELOPMENT
The proposed development is to involve the construction of a new residential dwelling on the
established residential type property. The proposed construction is intended to replace the existing
residence and be positioned as per the attached siting plan (refer appendix D) with a nominated off‐
set distance of between 6.0 metres and 6.021 metres from the front Eastern boundary, 2.450 metres
from the Southern side boundary, between 1.555 metres and 2.591 metres from the rear Western
boundary. The construction is to comprise of a double storey dwelling with a timber floor on bearers
and joists to the upper level supported by slab on ground to the lower floor. The external finish is to
comprise of selected cladding with a sheet metal roof. A inground swimming pool and water tank
are also proposed. These structures are to be positioned to the North Western aspect of the block,
adjacent to the proposed residence. New retaining walls and a masonry block wall fence are to be
included as part of the required landscaping.
Earthworks are to involve the demolition and removal of the existing dwelling and associated
structures including retaining walls located to the rear of the block. With a nominated platform level
of R.L 17.8 AHD, it is understood that only a site scrap will be required to achieve desired ground
levels.
Section 4
4.0 Overview
4.1 Regional Setting and Site Description
The site under review is identified as being an established residential type allotment 556 square
metres in overall area, regionally located approximately 9.5 kilometres North of Mount Coolum and
approximately 0.5 kilometres West of the coast. The property is positioned within an established
suburb and is bounded by similar, established residential type properties. Vegetation consists of
grass, gardens and trees. The natural unaltered slope is assessed as being moderate with a general
cross fall sloping roughly from South to North
The general topography comprises of the undulating, rounded sand hills and ridges bounded by low
lying coastal swamps and flats.
Fig. 1 – Topography Map, Qld Globe – Queensland State Government.
4.2 Regional Geology
Reference to the Department of Natural Resources, Mines and Energy electronic series indicates
that the site is located near the geological boundary between the following units :
1. Qhd/2‐SEQ of the Holocene age comprising of quartz sand; Holocene blowout dunes.
2. Qpt‐QLD of the Pleistocene age comprising of sandy mud, muddy sand, minor gravel;
estuarine deposits.
3. Qhb‐SEQ of the Holocene age comprising of quartz sand; Holocene beach deposits.
Fig. 2 ‐ Regional Geology ‐ Department of Natural Resources, Mines and Energy, QLD State Government.
Section 5
5.0 GEOTECHNICAL INVESTIGATION
5.1 Fieldwork
Two (2) bore holes were undertaken across the site using a power auger mounted to the rear of a
4WD utility to a maximum depth of 2.1 metres. Dynamic Cone Penetrometer (D.C.P) tests were
undertaken at the time of the site investigation. The bore holes were drilled using solid flight augers
fitted with a steel ‘V’ shaped bit or tungsten carbide bit.
An authorised representative from STA Consulting Engineers set out the bore holes locations from
existing site features, directed sampling and logged bore hole profiles. Engineering logs of the bore
holes are presented in Appendix A, together with Explanation Sheets defining the terms and symbols
used in the preparation of the logs.
5.2 Subsurface Conditions
The sequence encountered by the bore holes typically included a loose silty sand overlying a
medium dense sand for the extent of the bore holes undertaken. The following table is a summary
of the subsurface profiles observed:‐
Bore Hole Summary
Bore Silty Sand (m) Sand (m) Termination Depth
Hole # (m)
BH # 1 0.0 ‐ 0.3 0.3 ‐ 2.1 2.1 m
BH # 2 0.0 ‐ 0.2 0.2 ‐ 1.6 1.6 m
5.3 Groundwater
Groundwater was not identified at the time of the subsurface investigation. It must be noted that
ground moisture and ground water depths are typically influenced by climatic conditions and the
permeability of the soils observed and may vary with seasonal change.
6.0 SLOPE STABILITY ASSESSMENT
6.1 Stability Assessment Findings
At the time of the site assessment, the following observations were made:‐
Situated between a prominent sand ridge to the East and a rounded sand dune/ hill to the
West, topographically the site is positioned mid to lower slope.
The predominate land shape is concave.
The natural slope conditions had been altered in order to accommodate the existing
residence. However taking into consideration surrounding features, the natural unaltered
slope is assessed as being moderate with a general cross fall sloping roughly from South to
North estimated at approximately 3 to 5 degrees, increasing in fall further to the North of
the property particularly where the development abuts the National Park.
From visual assessment only, it appears that the original earthworks have involved cut and
filling of the site in order to create a level property. Timber type retaining walls have been
used to support cut and fill batters. A number of these walls have reached or exceeded their
expected service life with rotation and deterioration of the timbers evident.
The site is connected to the mains storm water and sewer networks; therefore outflows are
to be directed to these mains.
No ground water or surface water seepage was observed, nor was any vegetation such as
reeds/ sedge grasses typically associated with wet areas identified.
Section 6
No tension cracks were observed on or across the slope within the vicinity of the site.
Hummocky or bulging soils were not identified on or at the base of the slope within the
vicinity of the site.
The site is surrounded by a mix of existing residential construction including predominately
slab on ground type construction. From visual inspection only, all appear to be performing as
intended.
6.2 Desktop Assessment Findings
A review of historical imagery has been undertaken. No indicators of past landslip activity or
instability on or surrounding the nominated building sites could be identified from these
images.
Fig. 3 – Image Era ~ 1974 QImagery, Qld State Government
With reference to the Landslide Hazard Overlay interactive mapping by the Noosa Shire
Council we have identified aspects of the site as having a Moderate Hazard area.
Fig. 4 – Landslide Hazard Overlay – Noosa Shire Council Interactive Maps.
Section 7
6.3 Hazard Identification
A Hazard is defined as a condition with the potential for causing an undesirable consequence (the
landslide).
The hazard assessment given in this report is consistent with the procedures outlined in the report,
“A Method of Zoning Landslide Hazards” by MacGregor and Taylor, 2001. The following major site
features have been considered in determining a likelihood estimate or Frequency Analysis in turn, the
potential Hazard of the site in order of undertaking the final risk assessment for the proposed building
zone and immediate surrounds :
‐ The Natural Slope Angle ‐ The Natural Slope Shape/ Formation
‐ Local Area Geology ‐ Material Strength
‐ Concentration of Surface Water ‐ Evidence of Groundwater
‐ Evidence of Past Forms of Instability
From the results of studies undertaken by SMEC in similar terrain a correlation between relative
frequency and potential Hazard Rating has been determined as presented in the following table :‐
The following summarises the relative frequency calculation adopted following the guidelines of the
Landslide susceptibility analysis form extracted from the document ‘Landslide Susceptibility
Assessment Report’ for the City of Gold Coast, SMEC, August 2011. The complete form can be found
in appendix B;
Feature Description Risk Level
Natural Surface Slope Less than 5 degrees Low
Slope Shape Concave High
Site Geology Sedimentary Rock Moderate
Soil Conditions Residual > 3.0 m High
Evidence of Groundwater None apparent Low
Fill Height None Identified Low
Cut Height Less than 1.0 m Moderate
Slope of Cut Face 30° and 45° Very High
Material in Cutting Soil Very High
Cut Slope Support Timber Retaining Wall High
Concentration of Surface Water Lower Slope High
Waste Water Disposal Fully Sewered Moderate
Stormwater Disposal All Stormwater Piped to Street Drainage Low
Evidence of Instability No Sign of Instability Low
As an opinion, the hazard for the nominated building location and surrounds of such is provisionally
outlined below:‐
Applied Relative Frequency Hazard Rating
0.52 Low
Section 8
6.4 Qualitative Risk Assessment
With reference to the Australian Geomechanics Society (AGS) ‘Landslide Risk Management Guideline
2007’, as per Section 8.0 ‘Risk Assessment’, the main objectives of risk evaluations is usually to decide
whether to accept or treat the risks and to set priorities. The ‘Tolerable Risk’ criteria are usually
imposed by the regulator (local Authority), unless agreed otherwise.
The AGS guidelines define ‘Risk’ as a measure of probability and severity of an adverse effect to health,
property or the environment. Risk is often estimated by the product of probability and consequences.
In these guidelines risk is further defined as;
a) For Life Loss, the annual probability that the person most at risk will lose his or her life taking
account of the landslide hazard and the temporal spatial probability and vulnerability of the
person.
b) For property loss – the annual probability of the consequence or the annualised loss taking
account of the elements at risk, their temporal spatial probability and vulnerability.
A qualitative assessment involves an analysis which uses word form, descriptive or numeric rating
scales in order to describe the magnitude of potential consequences and the likelihood that those
consequences will occur. The Risk evaluation involves making judgements about the significance and
tolerability of the estimated risk. Evaluation may involve comparison of the assessed risks with other
risks or with risk acceptance criteria related to finance, loss of life or other values.
A qualitative landslide risk has been calculated taking into consideration the applied hazard rating and
the intended development as described by the client. It must be noted, the residual risk level
determined is conditional on the risk mitigation measures as outlined in Sections 7.0 of this report
being fully implemented and maintained for the expected life of the structure.
The elements considered within the risk assessment are as follows:
The intended/ proposed buildings and associated outbuildings.
Persons or Occupants on site.
As per the AGS guidelines, Qualitative Terminology used in assessing likelihood, consequence and risk
is presented in the following tables;
Likelihood Indicative Annual Description
Probability
Barley Credible 10‐6 The event is inconceivable or fanciful over the design life.
Rare 10‐5 The event is conceivable but only under exceptional
circumstances over the design life
Unlikely 10‐4 The event might occur under adverse conditions over the
design life.
Possible 10‐3 The event could occur under adverse conditions over the
design life.
Likely 10‐2 The event will probably occur under adverse conditions over
the design life.
Almost Certain 10‐1 The event is expected to occur.
Section 9
The potential implications for the associated risk level are outlined within the table below:‐
Risk Level Implications
VH (Very High Risk) Unacceptable without treatment. Extensive detailed investigation and
research, planning and implementation of treatment options essential to
reduce risk to Low; may be too expensive and not practical. Work likely to cost
more than the value of the property.
H (High Risk) Unacceptable without treatment. Detailed investigation, planning and
implementation of treatment options required to reduce risk to Low. Work
would cost a substantial sum in relation to the value of the property.
M (Moderate Risk) May be tolerated in certain circumstances (subject to regulator’s approval)
but requires investigation, planning and implementation of treatment options
to reduce the 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 is required.
VL (Very Low Risk) Acceptable. Manage by normal slope maintenance procedures.
Note: 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.
The table below outlines our qualitative assessment of landslide risk for the development site.
Hazard Likelihood Consequence Assessed Comments
to Property Risk
1. Shallow failure Rare due to the nature of the
through the Rare Minor Very Low underlying soils, the gentle gradients
residual soils on of the natural slope. The consequence
slopes <15 º of such instability would be Minor with
the resultant risk being Very Low.
2. Failure of existing This has been assigned as almost
timber retaining Almost Insignificant Low certain due to the observed
walls located to the Certain performance of the existing timber
rear of the type retaining walls. The consequence
property. would be insignificant due to the
landscape nature and height of walls
(<1.0 m) with the resultant risk being
Low . The design and construction of
these walls had not been supplied,
therefore have not been
independently verified by STA. The
stability/ integrity of the existing
retaining walls remain the
responsibility of the owner/ builder
and design engineers.
3. Deep seated failure Whilst the consequence of such a
within the residual Barely Major Very Low failure would be major, the likelihood
soil profile or Credible is barley credible due to relatively
weathered rock. gentle gradients and absence of
evidence of instability of such nature.
The resultant risk is Very Low.
On the basis of the qualitative risk assessment of likelihood and consequence presented in the table
above, the risk of the area assessed is determined as ‘Low’. This level of risk is acceptable; manage by
normal slope maintenance procedures.
Section 10
7.0 COMMENT & RECOMMENDATIONS
The area of the proposed structure has been defined as Low Risk providing the following
recommendations are implemented, managed and maintained for the expected life of the structure
:‐
7.1 House Design
As indicated by the client, the proposed development is to involve the construction of a new
residential dwelling on the established residential type property. The proposed construction is
intended to replace the existing residence and be positioned as per the attached siting plan (refer
appendix D) with a nominated off‐set distance of between 6.0 metres and 6.021 metres from the
front Eastern boundary, 2.450 metres from the Southern side boundary, between 1.555 metres and
2.591 metres from the rear Western boundary. The construction is to comprise of a double storey
dwelling with a timber floor on bearers and joists to the upper level supported by slab on ground to
the lower floor. The external finish is to comprise of selected cladding with a sheet metal roof. A
inground swimming pool and water tank are also proposed. These structures are to be positioned to
the North Western aspect of the block, adjacent to the proposed residence. New retaining walls and
a masonry block wall fence are to be included as part of the required landscaping.
Earthworks are to involve the demolition and removal of the existing dwelling and associated
structures including retaining walls located to the rear of the block. With a nominated platform level
of R.L 17.8 AHD, it is understood that only a site scrap will be required to achieve desired ground
levels.
STA Consulting Engineers are satisfied that a construction type as described above is
considered suitable for this site providing the following recommendations outlined are
implemented and maintained for the life of the structure.
7.2 Earthworks
Retain the existing natural contours wherever possible.
Where the removal of trees and/or existing structures is undertaken the voids created by
their removal, must be over excavated, back filled and compacted with suitable material.
All earthworks to be carried out in accordance with the requirements of Australian Standard
AS 3798 Guidelines on Earthworks for Commercial and Residential Developments.
Cuts – Existing/ Proposed
Support all cut batters with suitably designed retaining walls. Replace all existing walls that
show signs of stress or deterioration.
Drainage measures MUST be installed immediately up slope and behind all cut batters
including those retained to capture both surface and subsurface water movements and divert
waters to a suitable, controlled outflow below and clear of the building envelope. All drains
must be maintained for the life of the structure.
No excavation is to be undertaken within the zone of influence of any existing structure on or
adjoining the site (including retaining walls, sewer and storm water infrastructure etc..) unless
it can be shown that measures have been implemented to protect the stability of these
structures during and after construction. This should be determined by the design engineer.
Section 11
Fills ‐ Minimise height.
Support filled batters with engineered retaining walls or profile to an appropriate slope. For
this site, exposed fill batters are to be profiled no greater than the following :‐
Safe Batter Profile Angles/ Heights
Material Temporary Permanent Maximum Unsupported
Batter Height
Uncontrolled Fill 1V : 2H 1V : 4H 1.0 m
Engineered Controlled Fill 1V : 1H 1V : 2H 1.0 m
Note: The safe batter profile angles given are for un‐surcharged batters only.
Strip vegetation, topsoil and key/ bench the natural slope prior to filling. Fill is not to be simply
placed onto sloping surfaces greater than ~ 7 degrees.
Use clean fill materials and compact to engineering standards. Fill should be placed in
maximum 200 mm deep layers and be compacted to a minimum of 95 % Standard Maximum
Dry Density for cohesive (clay) material or 70 ‐ 90 % Relative Density for non‐cohesive (sand)
materials.
Structural filled batters should be over constructed by filling beyond the required final batter
face and cut back/ trimmed enabling machines to adequately compact the entire fill batter.
The finished platform must not slope towards the filled embankment which will allow water
to flow/ cascade over the exposed face. Ponding water on the platform must also be
avoided.
Consideration must be given to ensure that no surcharge loading from proposed filling is
imposed onto any existing infrastructure (including retaining walls, sewer and storm water
infrastructure etc..) unless it can be shown that measures have been implemented to
protect the stability of these structures during and after construction. This should be
determined by the design engineer.
7.3 Foundations
Footings should be founded within the medium dense to dense sand profile. This is to be
determined by the designing engineer.
On site foundation inspections including footing, slab & retaining walls must be undertaken
by a suitably qualified and experienced Geotechnical Engineer.
7.4 Drainage
The control of surface and subsurface water is critical to the overall performance of this site. All
surface and subsurface water must be captured and directed off site via a suitable outflow. Water
MUST not be left to pond on site, nor is water to be left to cascade over any cut or fill batter. Some
basic guidelines include but are not limited to:‐
Surface
Provide drains at the top of all cut and fill slopes, including those retained.
Discharge under controlled conditions (i.e. pipe) to the street drainage.
Provide and maintain general falls within drains to prevent blockage by siltation.
Line spoon drains to minimise the infiltration of surface water and make drains flexible
where possible.
Subsurface
Provide filters around all subsurface drainage.
Provide appropriate drainage behind ALL retaining structures.
Use flexible pipelines with access for long‐term maintenance.
Prevent the inflow of surface water.
Section 12
Waste Water & Storm water
The site is connected to the mains sewer and storm water systems. All outflows are to be
directed to these mains.
Storage tanks should be watertight and adequately founded. Overflows are to be piped to
the existing storm water system.
7.5 Erosion Control & Landscape
Control erosion as this may lead to instability.
Slope protection measures shall be carried out on exposed batters in order to mitigate the
development of stability and erosion issues. These works shall be carried out in a timely
fashion after the batter is exposed.
Re‐vegetate exposed with shrubs, grasses and ground covers preferably with plants
indigenous to the local area.
Section 13
8.0 COMPLIANCE CERTIFICATION
For final building approvals, a compliance certificate may be required by the local authority to assess
that the relevant slope aspects of the development have been constructed in accordance with the
recommendations contained within this report.
In the event that a this certificate is required and as good practise in general, site inspections by STA
Consulting should be carried out at various stages of the development. This shall include, as a
minimum:
1. Site preparation works prior to building construction. This may include inspection on
topsoil stripping, cut and fill batters (temporary and/or permanent), drainage
measures etc.. This inspection would enable the identification of areas of
geotechnical concerns at the early stage of development.
2. Work Completion. This inspection is expected to assess the compliance with the
recommendations in this report and advise if further works are needed.
Inspections pertaining to footings, slab, retaining walls etc.. should be carried out
separately to the above inspections.
It should be noted, STA Consulting reserves the right to decline a request for a compliance inspection
and subsequent certification on the basis we have not undertaken staged site inspections as outlined
above.
9.0 CONCLUSION
In conclusion, it is our considered opinion, from a geotechnical viewpoint that the site is suitable for
the proposed residence that had been indicated by the client at the time of writing this report.
This recommendation is subject to the implementation of the measures specified within this report.
On site foundation inspections including footing, slab & retaining walls must be undertaken by a
suitably qualified and experienced Engineer.
Thank you for entrusting us with this work, if we can be of any further assistance in this matter,
please let us know.
For and on behalf of
STA Consulting Group Pty Ltd
Digitally signed by STA Consulting Engineers
DN: c=AU, st=Queensland, l=Brisbane,
o=STA Consulting Engineers, cn=STA
Consulting Engineers,
[email protected]
Robin Cao BEng Justin J Williamson
MIEAust CPEng NPER RPEQ 12198 A.D. Civil Eng. Cert. Mining Eng
Section 14
APPENDICES [OCR of page images] APPENDICES
Section 15
APPENDIX A Soil Profile and Laboratory Results [OCR of page images] APPENDIX A Soil Profile and Laboratory Results
Section 16
Project Job No. 205860
Bore Log Sheet
Bore Hole # 1 Bore Hole # 2
Project Job No. ES205860-B
Client: Brisbane Construction Group Drill Method: Power Auger Drill Method: Power Auger
Pty Ltd
D.C.P blows/ 100 mm
D.C.P blows/ 100 mm
Sample Location
Sample Location
Depth (m)
Depth (m)
Groundwater
Groundwater
SOIL DESCRIPTION SOIL DESCRIPTION
Extent of Fill
Extent of Fill
Graphic Log
Graphic Log
N'q (kPa )
PP Value
PP Value
N'q (kPa)
Symbols
Symbols
0 (SM) silty SAND, fine to med. sands
0 (SM) silty SAND, fine to med. sands
(Grey), Moist and Loose (Grey), Moist and Loose
(SP) SAND, fine to med. sands
(SP) SAND, fine to med. sands (Grey White), Dry to Moist and med. dense
0.5
(Grey White), Dry to Moist and med. dense 0.5
3
3
3
4
1.0 4 1.0
4
4
1.5 1.5
END
2.0 2.0
END
2.5 2.5
3.0 3.0
3.5 3.5
4.0 4.0
4.5 4.5
5.0 5.0
Bore Hole Terminated - 2.1 m Bore Hole Terminated - 1.6 m
Terms :-
D.C.P.:- Dynamic Cone Penetrometer Note : kPa value is allowable bearing pressure caculated in accordance
N'q:- Allowable Bearing Capacity (kPa) with paper 'Determination of allowable bearing pressure under small structures'
PP:- Pocket Penetrometer Strength (kPa) by M.J Stockwell (June 1977)
U.T.P:- Unable to Penetrate
Slope Direction
STA CONSULTING ENGINEERS Client
Brisbane Construction Group Pty Ltd
Site Address
Lot 35 No.285 DAVID LOW WAY PEREGIAN BEACH 4573
Brisbane (Eight Mile Plains) (07) 3071 7444 Gold Coast (07) 3071 7444 Newcastle (02) 4032 6450
email: [email protected] webpage: www.staconsulting.com.au 58 Kempsie Road UPPER MOUNT GRAVATT 4122
STASOD.2014-14-05
Section 17
Project Job No. 205860
Site Sketch ( Not to Scale )
(All Dimensions Shown are Approximate Only)
Existing Established
Dwelling
Retaining Wall
Retaining Wall
Existing Shed
2. Existing Shed Laboratory Test Results
Sample Location:- N/A
Depth of Sample:- N/A
Liquid Limit:- N/A
(SLOPE 2 %)
Linear Shrinkage:- N/A
Iss:- N/A
Retaining Wall
Classification by characteristic surface movement as per AS2870-2011
Existing House SITE CLASSIFICATION SYMBOLS DESIGN Y'S RANGE GENERALISED DESCRIPTION
(Guide Only)
Most sand and rock sites with little or no ground movement from
'A' 0 < Ys
moisture changes.
Existing Established
Existing Established Slightly reactive clay sites, which may experience only slight ground
Dwelling 'S' 0 < Ys < 20
Dwelling movement from moisture changes
Moderately reactive clay or silt sites, which may experience moderate ground
'M' 20 < Ys < 40 movement from moisture changes
Highly reactive clay sites, which may experience high ground movement
'H1' 40 < Ys < 60 from moisture changes
Highly reactive clay sites, which may experience very high ground movement
'H2' 60 < Ys < 75 from moisture changes
Extremely reactive clay sites, which may experience extreme ground
'E' Ys > 75 movement from moisture changes
1.
Problem sites which generally have soils associated with uncontrolled fill,
'P' N/A abnormal moisture conditions (trees), soft or collapsing soils, landslip etc..
For classes M, H1, H2 and E this further classification may be required, based
'- D' N/A on the depth of expected moisture change. Applied to sites with deep-seated
moisture changes characteristic of dry climates and corresponding to a design
depth of suction change (Hs), equal to or greater than 3 metres.
Test Methods: AS1289 3.1.2 (liquid limit), 3.4.1(linear shrinkage), 7.1.1(shrink-swell)
Note - Tree heights (Ht) nominated are STREET
approximate and do not represent the
potential mature height of the tree.
STA CONSULTING ENGINEERS Client
Brisbane Construction Group Pty Ltd
Site Address
Lot 35 No.285 DAVID LOW WAY PEREGIAN BEACH 4573
Brisbane (Eight Mile Plains) (07) 3071 7444 Gold Coast (07) 3071 7444 Newcastle (02) 4032 6450
email: [email protected] webpage: www.staconsulting.com.au 58 Kempsie Road UPPER MOUNT GRAVATT 4122
STASOD.2014-14-05
Section 18
APPENDIX B Landslide Frequency Analysis [OCR of page images] APPENDIX B Landslide Frequency Analysis
Section 19
GEOLOGY: Qhd/2‐SEQ
Location: Lot 35 on RP203515 (No.285) David Low Way,
Peregian Beach Qld 4573
1. Natural Surface Slope 8. Slope of Cut Face
Area Level Factor
Area Level Factor
Less than 30 Degrees L 0.5
x Less than 5 degrees L 0.1
x Between 30 and 45 VH 1
Between 5 and 15 M 0.5
Degrees
Degrees
Between 45 and 60 VH 1.5
Between 15 and 30 M 0.8
Degrees
degrees
Greater than 60 VH 3
Between 30 and 45 H 1.2
Degrees
degrees
More than 45 Degrees M 0.8
9. Material in Cutting
Area Level Factor
2. Slope Shape
Area Level Factor High Strength Rock L 0.5
Crest or ridge L 0.7 Medium Strength Rock L 1
Planar/ Convex M 0.9 Low Strength Rock M 1.2
Rough/ Irregular M 1.2 Very Low Strength Rock H 1.5
and Soil
x Concave H 1.5
x Soil VH 2
3. Site Geology
Area Level Factor 10. Cut Slope Support
Area Level Factor
Volcanic Extrusive Rock H 1.1
Concrete Wall L 0.5
x Sedimentary Rock M 1
Crib Wall M 0.9
Low Grade Metamorphic M 1
Rock Gabion Wall M 1
High Grade Metamorphic L 0.9 Rock Wall H 1.5
Rock Timber Wall H 2
x
Volcanic Intrusive Rock M 1
Unsupported H 2
4. Soils
Area Level Factor 11. Concentration of Surface Water
Area Level Factor
Rock at Surface VL 0.1
Ridge L 0.7
Residual Soil < 1m deep L 0.5
Crest M 0.8
Residual Soil 1 - 3m deep M 0.9
Upper Slope M 0.9
x Residual Soil > 3m deep H 1.5
Mid Slope H 1.2
Colluvial Soil < 1m deep H 1.5
x Lower Slope H 1.5
Colluvial Soil 1 - 3m deep VH 2
Colluvial Soil > 3m deep VH 4
12. Wastewater Disposal
Area Level Factor
5. Fill Height
Area Level Factor x Fully Sewered M 1
None L 0.9 Onsite Disposal - M 1.2
x Surface
Less than 1.0 m M 1.1
Onsite Disposal - Soak H 1.5
Between 1.0 m and 3.0 m M 1.3 Pit /Trench
Between 3.0 m and 6.0 m H 1.7
Greater than 6.0 m VH 2.5 13. Stormwater Disposal
Area Level Factor
6. Evidence of Groundwater x All Stormwater Piped to L 0.7
Area Level Factor Street Drainage
Rainwater Tank with M 1
x None Apparent L 0.7
Overflows
Minor Moistness M 0.9 Stormwater Discharge H 1.5
Generally Wet H 1.5 on Site
Subsurface Springs VH 3
14. Evidence of Instability
Area Level Factor
7. Cut Height
Area Level Factor x No sign of instability L 0.8
None (Go to section 11) L 0.9 Soil Creep H 1.2
Less than 1.0 m M 1.1 Minor Irregularity VH 2
x
Between 1.0 m and 3.0 m M 1.3 Major Irregularity VH 5
Between 3.0 m and 6.0 m H 1.7 Active Instability VH 10
Greater than 6.0 m VH 2.5
Section 20
Summary
1 Natural Surface Slope L 0.1 Relative Frequency Hazard Rating
2 Slope Shape H 1.5 < 0.2 Very Low
3 Site Geology 0.2 - 0.6 Low
M 1.0 0.6 - 2.0 Moderate
4 Soils H 1.5 2.0 - 6.0 High
5 Fill Height L 0.9 >6 Very High
6 Evidence of Groundwater L 0.7
7 Cut Height M 1.1 Relative Frequency = 0.52
8 Slope of Cut Face VH 1.0
9 Material in Cutting VH 2.0 Hazard Rating = Low
10 Cut Slope Support H 2.0
11 Concentration of Surface Water H 1.5 *The numerical factor allocation to these site features are based on
12 Wastewater Disposal judgement and experience observed at time of assessment.
M 1.0
13 Stormwater Disposal L 0.7
14 Evidence of Instability L 0.8
9 Relative Frequency L 0.52
(1x2x3x4x5x6x7x8x9x10x11x12x13x14)
Section 21
APPENDIX C Site Photographs [OCR of page images] APPENDIX C Site Photographs
Section 22
Fig.5. View West to site from road. Fig.6. View South West towards existing residence. [OCR of page images] Fig.6. View South West towards existing residence.
Section 23
Fig.7. View South, South East across backyard area. Fig.8. View North across backyard. [OCR of page images] Fig.8. View North across backyard.
Section 24
APPENDIX D Site Map and Architectural Drawings [OCR of page images] APPENDIX D Site Map and Architectural Drawings
Section 25
Fig. 9. Aerial Image – Qld Globe, Queensland State Government. [OCR of page images] Fig. 9. Aerial Image - Qld Globe, Queensland State Government.
Section 26
Fig. 10. General Contours – Noosa Shire Council Interactive Maps. [OCR of page images] Fig. 10. General Contours - Noosa Shire Council Interactive Maps.
Section 27
GENERAL NOTES: NOTE: NOTES:
1.ALL DIMENSIONS AND FLOOR AREAS ARE TO BE WHILE ALL CARE IS TAKEN IN THE SITING - All building work shall be carried out in accordance with the
Building Code of Australia,
VERIFIIED BY BUILDER.
2. LEVELS SHOWN ARE APPROXIMATE UNLESS
OF THIS HOME, IT MAY VARY DUE TO - Smoke detectors to be hard wired and interconnected in
ACCOMPANIED BY REDUCED LEVELS BY A REGISTERED ESTATE COVENANT, LOCAL COUNCIL, accordance with part 3.7.2. of the BCA and AS3786,
- Provide Termite protection in accordance with AS3660.1,
SURVEYOR. STATE GOVERNMENT, QUEENSLAND - All timber framing generally to be in accordance with AS1684,
3. FIGURED DIMENSIONS ARE TO BE TAKEN IN Part 3.4.4 of the BCA,
PREFERENCE TO SCALING.
DEVELOPMENT CODE, ENERGY - Mechanical ventilation shall be installed in accordance with
1,268 WALL
4.ALL BOUNDARY CLEARANCES MUST BE VERIFIED BY THE EFFICIENCY REQUIREMENTS, SITE AND AS1680.0
- Masonary materials and construction to be in accordance
SURVEYOR PRIOR TO COMMENCEMENT OF ANY BUILDING SOIL CONDITIONS AND THE APPROVAL OF with AS3700
WORK.
5. WHERE ENGINEERING OR HYDRAULIC DRAWINGS ARE ANY BOUNDARY RELAXATIONS REQUIRED. -AS3740
All internal wet areas to be waterproofed in accordance with
REQUIRED, SUCH MUST BE TAKE PREFERENCE TO THIS - Provide lift-off hinges to all toilet doors with an internal length
DRAWING. of 1900mm or less.
- Plumber to Provide Location & Design Plans for On-Site Rain
6. STORMWATER TO BE CONNECTED AND DISCHARGED TO
Water Tanks to Building to be submitted at Time of Approvals
COUNCIL'S REQUIREMENTS AND TO AS 3500.3-1990. (where applicable). To be designed to all Australian Standards
7. ALL SERVICES TO BE LOCATED AND VERIFIED BY THE & BCA.
BUILDER WITH THE RELEVANT AUTHORITIES PRIOR TO THE WARNIN - All components of a Water System Intended for rainwater
ELECTR G
COMMENCEMENT OF ANY BUILDING WORKS. ICAL INFR tank application must comply with Plumbing and Drainage Act
IN THIS ASTRUC
2002 (Act) & public health requirements.
2106213061
VICINITY TURE
26.520
PAG02
PLOTTE
NOTE: THESE DRAWINGS ARE TO READ IN CONJUNCTION RECORD D FROM
S ONLY.
WITH TENDER DOCUMENTS AND SCHEDULE OF FINISHES. A Rainwater Tank must:
36 WARNIN - incorporate acceptable devices to ensure a continuous
THE TENDER DOCUMENTS ARE TO TAKE PRECEDENCE TELSTR
A INFRA
G
P9316 IN THIS STRUCTU supply of water to all internal fittings.
OVER THE DRAWINGS. VICINITY RE
PLOTTE
D FROM - incorporate appropriate back-flow prevention devices to
PROPOSED UNDERGROUND RAINWATER TANK LOCATION RECORD
S ONLY. prevent tank water from entering the reticulated water supply
43 PROPOSED RETAINING WALLS - IMPORT FILL AS REQUIRED WARNIN
network in accordance with AS/NZS 3500:2003 Plumbing &
P9316 WATER G Drainage.
INFRAS
IN THIS TRUCTU - incorporate acceptable screens or methods of preventing
VICINITY RE
PLOTTE
1,555 WALL RECORD D FROM mosquitoes and vermin entering the tank.
REMOVE EXISTING S ONLY.
1,549 WALL
PROPOSED BLOCK - a screened downpipe rainhead, having screen mesh 4-6mm
RETAINING WALLS
WALL FENCE WARNIN
G and Designed to prevent leaves from entering each downpipe.
SEWER
POOL INFRAS
2106213137
18.206
FE10
2106213160
2106213148
2106213136
17.957 17.948
17.957
FE10 FE10
2106213130
17.948
Timber Fence IN THIS TRUCTU
VICINITY RE
TRW01
BRW01
-
18
2106213161
87°13' FENCING PLOTTE The placement of a rainwater tank and its overflows must be
3,425 WALL
17.757
D FROM
FE10
.2
RECORD
2106215130
17.353
S ONLY. Designed to ensure Stormwater does not:
17.8
FE10
33|535 2106213013
16.955
- pond under building floors.
Block Wall
ES01
PROPOSED
2106215136
17.369
FE10
2106213129
2106213176
POOL
18.330
17.924
TRW01 2106213014
2106213172 WA06.U
16.958
Section 28
1,000
18.145
2106213162
2106213115 WA05.U
17.259 ES01
- flood around foundations and footings of buildings.
17.774 NS
BRW01 2106213169
-
18.728
2106213135
WA05.U
18.349
TRW01
LOCATION
2106213127 2106213048
17.806 16.907
2106213168
BRW01 NS
- 18.489
WA05.U
KEEP ALL SE -
2106213163
2106213175
17.318
17.900
NS
WA06.U
2106213167
18.748
- cause nuisance to neighbours.
WA05.U
2106213174
2106213134 17.912
18.324 WA06.U
FE10
2106213047
16.935
FE02
PROPOSED RETAINING RVICES Power Pole Stay Wire
2106213145
17.689
DP
CO03
2106213108
2106213106 17.725
17.672 CO03
CO03
2106213107
17.686
SH01.U.R
CEAR
S
18.4 2106213059
2106213058
23.792 23.792
WALLS - IMPORT FILL AS
PP01.UGW01.U
00
2106213056
24.315
IL 15.76
PAG01.U
SEUG02
2106213159
17.422 2106213060
GW01 24.570
PAG02.U
- Disperse surface water away from Building so no ponding of
IL 15.82
SEUG01
2106213003
17.097
SMH
REQUIRED
IL 15.81
57
SEUG03
DP
water occurs beside Building.
ll
POOL
1,1
9
Timber Retaining Wa
65
- Disperse all water away without nuisance to Neighbours.
2106213165
17.538
NS
FENCING
David l
3002
6,021 DECK
17.753
DH
DP 2106213057
22.381
PAG01.U
2106213164
17.581
NS
2106213133
18.550
2106213089
19.480
SH01.U
ALFRESCO
2106213088
2106213015
17.063
ES01
- Plumber to provide Stormwater and Sewer Plan to Council
nce
FE10 19.551
SH01.U
2106213046
17.202 2106213049
FE02 17.105
The text continues on section 29.
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