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Slope Stability AG-220616-RPT-G-01_[Rev A]
[email protected]
arcosgroup.com.au
ABN 51 640 311 841
Attention: Bliss Homes & Renovations 28 July 2022
By Email ARCOS PROJECT:220616
Report 01 Revision Rev A
Report on Geotechnical Investigation
Proposed Residential Development
8 Hinterland Close, Tinbeerwah
Arcos Unit Group Pty Ltd (Arcos Group) has undertaken a geotechnical investigation for the above project and client.
SUMMARY OF INVESTIGATION
Results of Australian Geomechanic Society Landslide Risk Assessment
Low
Note: The above is a summary of the detailed investigation results discussed within this report. The entire report must be read,
understood and kept in entirety.
Image Source: Nearmap
Geotechnical Engineer Senior Geotechnical Engineer
Cody Surawski B.Eng (Civ)(Hons), B.Env.Sc Andre Dos Santos B.Eng (Civ), MIEAust, RPEQ,
CPEng, NER
[email protected] [email protected]
For and On Behalf of Arcos Group For and on Behalf of Arcos Group
Sunshine Coast | Brisbane | Gold Coast
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ABN 51 640 311 842
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1 INTRODUCTION
Arcos Unit Group Pty Ltd (Arcos Group) was commissioned to undertake a geotechnical investigation for the project
at the location described on the title page of this report.
This report outlines the results of the investigation, laboratory testing, analysis, and interpretive reporting on the
following items:
Review of the existing slope stability hazards, their attributed risks and impacts of the proposed development in
alignment with the practices set out within the Australian Geomechanics Society guidelines; and,
Provide recommendations from a geotechnical context that will avoid or reduce any potential instability.
This report must be kept in entirety. The use of this document is exclusively undertaken in accordance with our terms
and conditions.
2 REGIONAL GEOLOGY
The site is in an area underlain by Late Triassic to early Jurassic aged Myrtle Creek Sandstone, which typically
comprises “Quartzose sandstone, orthoquartzite, sublabile to labile sandstone, siltstone, shale.”.
3 EXISTING STABILITY RISK
Local authorities prepare mapping tools to aid in assessing potential slope stability requirements. The mapping tools
are a “high level” approach where the site specific investigations are specific to a particular site/allotment. It is
important to note that where a site specific investigation and slope stability assessment are undertaken, they take
precedence.
Reference to the available overlays for the area show the site has been initially mapped as “Moderate” in terms of
landslide hazard.
4 GEOTECHNICAL INVESTIGATION
A geotechnical investigation was undertaken by Ground Drill Pty Ltd for the purposes of a site classification and
effluent report. The findings from their investigation are detailed in their report, a copy of which is attached; however
in summary, the conditions encountered consisted of gravelly silty sand overlying sandy clay, underlain by rock from
approximately 0.9 m below the existing ground surface. No groundwater was noted in their investigation. The
information from this previous investigation has been used as part of the analysis undertaken by Arcos. If any
discrepancies between the conditions reported by Ground Drill and the actual site conditions exist, reassessment of
the slope stability may be required.
5 ASSESSMENT
Geotechnical comments are based on the factual findings of the investigation, best practice, local experience,
published correlations; however, are fundamentally founded in opinion and this should be considered.
An assessment was undertaken by a Geotechnical Engineer. The proposed dwelling location is situated towards the
north-western corner of the block. The site slopes down from the north-western corner towards the south-eastern
side of the block. The slope angles are fairly uniformed at approximately 20°. No obvious signs of disturbed ground,
tension cracks or hummocks were noted in the vicinity of the proposed residence. The mature trees on site were all
observed to be typically vertical with no misshapen or curved trunks. Misshapen or curved trunks are usually good
indicators for previous slope instability.
Sunshine Coast | Brisbane | Gold Coast
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ABN 51 640 311 842
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Sunshine Coast | Brisbane | Gold Coast
6 AGS ASSESSMENT
Landslides are caused where a soil or rock mass has a decrease in strength, usually attributed to groundwater,
resulting in the material not being able to maintain its own self-weight resulting in a slope failure.
The Australian Geomechanics Society (AGS) developed a set of tools and procedures for assessing the stability of
a slope. The tools and procedures presented with the AGS documentation form the basis of the assessment
undertaken herein and their documentation is attached for reference.
The guidelines also identify that the regulator typically sets the standard for levels of tolerable risk. AGS defines
tolerable risk as “risks within a range that society can live with so as to secure certain benefits. It is a range of risk
regarded as non-negligible and needing to be kept under review and reduced further if practicable”.
The guides suggest that areas of moderate or greater risk should not be developed unless a rigorous remediation
plan be implemented to reduce the area to a level of Acceptable Risk. AGS defines acceptable risk as “risk which
everyone affected is prepared to accept. Action to further reduce such risk is usually not required unless reasonably
practicable measures are available at low cost in terms of money, time and effort.”.
AGS suggest that regulators generally accept risk levels of “low” or lower as a level of acceptable risk.
AGS prepared a semi-quantitative assessment tool for determining the level of risk for a site. The tool separates the
potential hazards for a site, from a stability context, and rates them with a level of risk frequency. The multiplication
of these individual risk frequency summates as the risk frequency rating which is then measured against the levels
of risk nominated by AGS.
The results of this analysis are shown in Table 1.
TABLE 1: AGS ASSESSMENT
Hazard Likelihood Consequence Risk Level
Global Failure Barely Credible Catastrophic Low
Creep in Shallow Soils Unlikely Minor Low
Rotational or translation slide down the Unlikely Minor Low
slope
Based on the results of the AGS assessment, the perceived risk based on the conditions encountered and information
available at the time of the assessment is “Low”.
7 HILLSIDE CONSTRUCTION
The following works should be implemented in addition to other items highlighted within this document. These points
are considered to be typical good hillside construction practice as explained in attached documentation:
Footings should be found a minimum of 0.3 m into bedrock.
Fill should be limited to no more than 1 m and should be step keyed into the existing slope. The fill should be
formed at no steeper than 3H:1V, unless retained by an engineered retention system. All fill should be placed in
accordance with AS3798.
Where slopes are not supported by an engineer designed support system, natural slopes within or near movement
sensitive areas should be no steeper than 2.5H:1V.
All stormwater and surface water is to be discharged by an approved stormwater drainage system. The use of
subsurface drainage systems are not suitable unless greater than 50 m downslope from the envelope at this site.
Ongoing maintenance of effluent wastewater areas are also considered mandatory. The location of the application
area should be located below the proposed building.
Sunshine Coast | Brisbane | Gold Coast
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ABN 51 640 311 842
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Sunshine Coast | Brisbane | Gold Coast
Plumbing and services must also not be allowed to leak and regular maintenance and inspections should be
undertaken.
Erosion protection of cut and fill betters will be required. Batters should incorporate crest and toe drainage. Batters
should be vegetated appropriately to minimise erosion.
Overland flow paths will need to be carefully directed to approved outlets to minimise erosion possibility.
8 GEOTECHNICAL RECOMMENCDATIONS
The following sections details specific geotechnical constraints or recommendations in addition to general hillside
construction notes.
8.1 FOOTINGS
In accordance with industry standards, a geotechnical engineer from Arcos should undertake the testing within the
footings to confirm that the encountered material is in alignment with the adopted parameters and assumptions
provided within this report. Where this does not occur, Arcos cannot be held liable for any of the information presented
within this report.
All footings will need to be designed to accommodate potential ground surface movement, settlement values and
any additional settlement values associated with the placement of new fill.
Settlement for suitably sized and designed high level footings should be in the order of 1-2% of the width of the
footing.
If footings are located adjacent to an underground service or other obstruction that is not homogenous with the
founding strata, the footing should be extended a minimum 0.3 m below an imaginary line projected at a 45 degree
angle from the lowest point of the service/obstruction. This is depicted graphically for reference:
The ultimate geotechnical end bearing and shaft adhesion parameters are presented in Table 2. The values given
will need to reduced by applying a suitable geotechnical strength reduction factor (Φg) for limit state or divided by a
suitable factor of safety for working stress methods. The Φg should be selected by the designer.
Based on the conditions encountered, bored piles would be considered suitable.
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TABLE 2: DEEP LEVEL FOOTING – ULTIMATE GEOTECHNICAL PARAMETERS (LONG PILE)
Material Bored Bored
Fb (kPa) Fs (kPa)
Very low strength sandstone* 1800 90
Notes: Fb = Base Bearing (Ultimate); Fs = Shaft Adhesion (Ultimate), *inferred to be the “distinctly weathered rock”
encountered in the previous geotechnical investigation.
The upper 1 m of soil profile should be ignored in shaft calculations for bored piles to allow for shrinkage cracks. The
values presented in Table 2 assume that the material equal to four pile diameters below the base of any footings is
as strong or stronger.
Settlement values are subjected to a variety of factors; however, a properly designed and constructed pile should
have a serviceability settlement between 1% and 2% of its’ diameter.
ATTACHMENTS
About Your Geotechnical Report
Interpretation of the Subsurface Sheets
Client Supplied Information (Soil Report by others)
Foundation Maintenance and Footing Performance: A Homeowner’s Guide
Sunshine Coast | Brisbane | Gold Coast
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ABN 51 640 311 842
arcosgroup.com.au
Sunshine Coast | Brisbane | Gold Coast
ABOUT YOUR GEOTECH REPORT
Reporting
These notes have been provided to clarify and The report has been prepared and reviewed by
enhance the reader’s understanding of the suitably qualified and experienced persons. The
terminology used throughout the report, and also to persons draw on previous experience, local
identify where limitations exist. All investigations are knowledge, published literature, and otherwise
undertaken based on budgetary constraints which standard engineering approaches and principals. The
impart a level of uncertainty as a result of limiting the context of which the report has been prepared for must
amount of investigation undertaken. be considered and if the context changes, due
consideration should be given to the possibility that the
report is no longer considered relevant and review by
Copyright Arcos Unit Group Pty Ltd must be undertaken.
This report remains the property of Arcos Unit Group Arcos Unit Group Pty Ltd undertakes quality
Pty Ltd at all times unless ownership is transferred in assurance checks in accordance with its’ quality
writing. It cannot be included in any documentation system requirements; however, restrictions on the
without the express written permission of Arcos Unit project outside of Arcos Unit Group Pty Ltd’s control
Group Pty Ltd can result in unanticipated variations, changes in
policy or interpretation of said policies by the relevant
authority, or the actions of contractors subject to
Subsurface Report Sheets (Bores etc) commercial pressure.
The provided subsurface sheets are inherently an
interpretation undertaken by a suitably qualified and
experienced person; however, the reliability of the
Site Variations
provided information will rely on the method of If site variations become evident at the time of
investigation. It is prudent to state that these sheets construction or after the release of a report, Arcos Unit
only represent a very small percentage of the Group Pty Ltd requests immediately notification. This
subsurface conditions across a particular project. notification is proposed in order to assist in
remediation prior to any permanent structures or
It reasons that given the relatively small representation
design procedures are undertaken.
of the subsurface conditions for a project, spacial
variability between testing locations must be taken into
consideration including the orientation of strata Collaboration
intersections.
Arcos Unit Group Pty Ltd strongly recommends open
The presence or lack of groundwater is usually stated and collaborative communication about the use and
on the subsurface sheets; however, it must be noted inherent interpretation of Arcos Unit Group Pty Ltd’s
that the measurements undertaken onsite are typically report. Please contact the author of the report to
very inaccurate and if the presence or lack of arrange for an obligation free discussion regarding the
groundwater will have any degree of affect on the potential benefits of having geotechnical consultants.
project, additional groundwater monitoring techniques
should be employed such as groundwater monitoring
wells.
Sunshine Coast | Brisbane | Gold Coast
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ABN 51 640 311 842
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Sunshine Coast | Brisbane | Gold Coast
Interpretation of the Subsurface Sheets
The terminology included on Arcos Unit Group Pty the most important component. Typically, the strength
Ltd’s has been evolved from AS1726:2016. Typically of rock is based on laboratory testing, tactile
a soil’s strength, colour, plasticity, grain size, other assessment and other observations as relevant. The
inclusions, and moisture will be described. A rock’s industry standard method for assessing the strength of
strength, weathering, colour, grain, and other rock in the field is to use the point load strength index
inclusions are typically described. (AS4133.4.1). It is important to note that the point load
strength index does not take into consideration the
degree of fracturing of a rock mass which can both
Soil lower and increase the overall rock strength. The
Soil is typically described by the components that strength of rock is broken down as follows:
make it up by percentage or whichever has a Very Low Strength (VLS) < 2 MPa (UCS)
governing behaviour. The types and sizes reproduced Low Strength (LS) 2 to 6 MPa (UCS)
from AS1726 are: Medium Strength (MS) 6 to 20 MPa (UCS)
Boulder >200 mm High Strength (HS) 20 to 60 MPa (UCS)
Cobble 63 to 200 mm Very High Strength (VHS) 60 to 200 MPa (UCS)
Gravel 2.36 to 63 mm Extremely High Strength (EHS) > 200 MPa (UCS)
Sand 0.075 to 2.36 mm Very Low Strength (VLS) < 0.1 Is(50)
Silty 0.002 to 0.075 mm Low Strength (LS) 0.1 to 0.3 Is(50)
Clay < 0.002 mm Medium Strength (MS) 0.30 to 1.0 Is(50)
The strength of soil is usually assessed by suitably High Strength (HS) 1.0 to 3.0 Is(50)
experienced persons through the use of laboratory Very High Strength (VHS) 3.0 to 10.0 Is(50)
test results, published literature, field assessments or Extremely High Strength (EHS) > 10.0 Is(50)
a combination of the above. The strength of soil is The Is(50) values are based on a correlation between
characterised into either cohesive (clays and silts) or the unconfined compressive strength (UCS) of 20.
cohesionless (sands and gravels) as shown below: This value varies significantly and site specific testing
Cohessive Soil Strength Term must take precedence.
Very Soft < 12.5 kPa Rock weathering is broken down as follows:
Soft 12.5 to 25 kPa Extremely weathered (EW) Behaves as soil but rock structure
Firm 25 to 50 kPa evident
Stiff 50 to 100 kPa Highly weathered (HW) Colour and strength of original fresh rock
is not recognisable. Decomposition of rock evident
Very Stiff 100 to 200 kPa
Moderately weathered (MW) Defects are heavily stained with
Hard > 200 kPa
rock mass showing signs of discolouration
Cohesionless Soils Strength Term (uncorrected Qc) Slightly weathered (SW) Some staining but minimal to no
Very Loose <2 MPa change in strength
Loose 2 to 5 MPa Fresh stained (FS) Minor staining evident
Medium Dense 5 to 15 MPa Fresh rock (FR) No change
Dense 15 to 25 MPa Rock fracturing is broken down as follows and can only
Very Dense > 25 MPa be accurately described where undamaged
continuous sampling has been undertaken:
Fragmented (Fg) Defect spacings < 20 mm
Rock
Highly Fractured (HF) Defect spacings 20 to 50 mm
Rock is typically described by the components that Fractured (Fr) Defect spacings 50 to 200 mm
make it up by percentage or whichever has a Slightly Fractured (SF) Defect spacings 200 to 1000 mm
governing behaviour. The strength of rock is typically Unbroken (Ub) Defect spacings > 1000 mm
Sunshine Coast | Brisbane | Gold Coast
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Ground Drill Pty Ltd ATF The Bennett
Family Trust ABN - 15204820396
M – 0407035220
W- www.grounddrill.com.au
E [email protected]
QBCC Lic – 15034580
Pomona QLD 4568
Site Classification Report
Job No: 22/224 Client Ref: N/A
Date: 16/06/22
Client: Bliss Homes & Renovations
Site Address: Lot 8 Hinterland Close, Tinbeerwah
Proposed Structure: Proposed Residence
Information Provided by Client: Plans
Page 13
Introduction
The purpose of this report is to classify the site in accordance with AS2870-2011. This report
is based on the field investigation/lab testing and information if any provided by the client.
This Report relates exclusively to the tested locations and the above-mentioned structure.
Further investigation may be required. Further investigation is recommended when deeper
depths of fill or marine clays are thought to be present, by way of deeper boreholes/other
test methods/use of prior investigation within the area. Bore logging in accordance with
AS1726-2017 Geotechnical Site Investigations.
Site Classification
Class “P” (Due to trees)
Based on the soil profiles the site would have the characteristics of
an 'M' site with an approximate Ys of 25-35mm if not a “P”.
Important Notes Relating to the classification
This report does not address slope stability, a slope stability report is required the services of a
suitably qualified Geotechnical Engineer should be sought.
Allowable Bearing Capacity
An approximate bearing capacity of 100kpa was encountered at a depth of 300mm
below existing ground surface level in the SANDY CLAY at location BH1 and location
BH2.
This is a suggested minimum founding depth; greater depth may be required due to the
following. Bearing capacity can be highly variable over the allotment these depths are
specific to the test locations. Actual founding depth should be nominated by the designing
engineer whilst taking construction and footing type, fill, underground services, retaining
walls, settlement, proposed cut/fill and any trees into account. Soft and/or settling soils may
present within the investigated depths or at deeper depths, further investigation may be
required to establish this.
Page 14
Lab Results/Predicted Surface Movement Bore Hole BH 1 300-600 Shrink-Swell 0.8% Ys N/A Site Description Future Site Works: Cut Existing Earthworks: Nil Retaining Walls: Nil Vegetation: Grassed, scattered large gums Slope: 27-30% Allotment Type: Acreage Surrounding Allotments: Acreage Surface Water: Surface water from the road will traverse this allotment Water Table: Not encountered Rock: Encountered Watercourses: Gully downhill Road Status: Sealed By using this report, you are agreeing to the statements and limitations mentioned in this report. Authorised Signatory Matthew Bennett on behalf of Ground Drill Pty Ltd QBCC Lic # 15034580
Page 15
Limitations of Report & Notes
This report is based on information gathered from the field investigation and information provided by
the client if any. Ground Drill should be notified immediately if ground conditions are found to differ
from this report during initial earthworks.
Unless otherwise stated this report does not address the following issues;
• Mining Subsidence.
• Slope Stability (If the site is in a known slip area or is steep, it is recommended that a
Geotechnical Engineer be engaged to conduct a Slope Stability assessment).
• Deep soft or settling soils
• Soils within investigated depths or deeper may be subject to settlement with additional load of
structure and any fill placed, the designing engineer is to allow for this potential settlement.
• Deep settling marine clays may be present.
• Soil Contamination, hazardous materials and or acid sulphate.
• Any slopes, dimensions or plans in this report are not to scale and only show approximate
testing locations.
• Flood levels (It is the client’s responsibility to inform us of any flood levels on the allotment).
• If water is found in the boreholes this depth may vary greatly over time. This report does not
address the influence any natural springs may have on the structure.
• It is the client’s responsibility to inform us of any nearby underground services that have been
or will be installed near the proposed structure.
• Earthworks could affect the site classification and or founding depth.
• If any fill is placed on the allotment post investigation the founding depth will change,
furthermore placement of reactive fill may change the sites classification.
• All topsoil and vegetation is to be removed.
• Surface water is to be diverted away from structure.
• Do not plant trees near the structure which could interfere with the footing’s performance.
• It is the owner’s responsibility to read and understand the CSIRO BTF 18 Foundation
Maintenance and Footing Performance: A Home-owner’s Guide.
• Strength of founding material can be highly variable dependent upon moisture content.
• This investigation undertaken consisted of the included boreholes/test pits, given the size of
the site it is possible that a problem could have been missed. eg. Filled dam/gully, soft soils,
fill, springs, boulders, rock etc. We cannot give a definitive assurance that none of these
problems exist on the site unless we did a greater number of boreholes which would be
uneconomical and impractical.
• This report may not provide all necessary information to design an adequate footing system,
further investigation may be required using larger drill rigs and/or different testing methods.
• This report relates exclusively to single or two storey residential structures, or structures with
similar loads. Larger commercial or greater than 2 storey structures may need further
investigation and this report is to be used as an initial guide only.
• If trees/palms are present, or have been removed from, within or near to the proposed
structure footprint, it is the responsibility of the designing engineer to use the principals of
AS2870-2011 Appendix H “Guide to Design of Footings for Trees”. The classification therefore
excludes the effect of trees on the site unless otherwise stated.
Distance from proposed structure that trees can affect footings:
0.75 x 'h' 'M' sites
1.0 x 'h' 'H' sites
1.5 x 'h' 'E' Sites
'h' is the mature height of the tree. Where there are rows of trees the distance should be
increased.
• It is the designing engineer’s responsibility to calculate the yt and add it to the ys.
• As per the Plumbing and Drainage Regulation 2019, all sites classified H1, H2, E or P must
have an articulating plumbing joint where connected to sanitary drainage. This should be
designed by a competent person (E.g. RPEQ or similar).
Page 16
Borelogs
BH 1 Soil Description DCP BH 2 Soil Description DCP
0 GRAVELLY SILTY SAND (SM) – Fine to 0 GRAVELLY SILTY SAND (SM) – Fine to
medium, brown, fine to medium gravel, medium, brown, fine to medium gravel,
dry, loose. dry, loose.
100 1 100 1
200 2 200 1
300 SANDY CLAY (CH) – High plasticity, 4 300 SANDY CLAY (CH) – High plasticity, 7
orange mottled grey, fine to medium orange mottled grey, fine to medium
sand, trace fine to medium gravel, sand, trace fine to medium gravel,
moist, stiff. moist, stiff.
400 7 400 13
500 8 500 8
600 9 600 7
700 9 700 9
800 9 800 8
900 DISTINCTLY WEATHERED ROCK 16 900 DISTINCTLY WEATHERED ROCK >20
(DW) – Fine, pale brown, dry, low (DW) – Fine, pale brown, dry, low
strength rock. strength rock.
1000 18 1000
1100 Auger Refusal 1100 Auger Refusal
1200 1200
1300 1300
1400 1400
1500 1500
1600 1600
1700 1700
1800 1800
1900 1900
2000 2000
*- DCP restarted down the borehole
SWL -Standing Water Level
PP- Pocket Penetrometer
ISS-Indicative Shrink-Swell
SS – Shrink-Swell
Page 17
Site Photos [OCR of page images] Site Photos
Page 18
ORO see wr , BOW Aeon Ie
Page 19
Foundation Maintenance
and Footing Performance:
A Homeowner's Guide
ings can and often do move. This movement can be up, down, lateral or rotational, The fundamental couse
Gy)
csiro
STF Is
replaces
Information
Sheet 10/91
of movement in bu lly be reloted to one or more problems in the foundation soil. It is important for
re ates ee nat ie rete an triodi nian
ane
foundation soil can be prevented, thus protecting ogainst building movement.
This Building Technology File is designed to identity causes of soil-related building movement, and to suggest
of prevention of resultant cracking in buildings.
Soil Types
‘The types of sails usually present under the topsoil in land zoned for
residential buildings can be split into two approximate groups —
granular and clay. Quite often, foundation soil is 2 mixture of both
Ee ee ee ear eee
caused by erosion. Clay soils are subject to
focentinn cack onic gecblonas
Classifications for a given arca can generally be obtained by
il
soils are peone to erosion, but samy soil is particularly susceptible
to being washed away. Even clay with a sand component of say 10%
or more can suffer from erosion.
Saturation
This is parti in clay soils. Saturation creates a bog-
like suspension iss so dea: cones cb las Vetualiy oll of io
bearing capacity. To a lesser degree, sand is affected by saturation
because saturated sand may ul a reduction in volume —
to the local but these are Feabl : “ee
cod there doubt» yoechical report dhol be commioned, Fact par oe Oa cud
As most buildings suffering movement problems are founded on clay ally be the of the builder.
soils, there is an i on claescaion of tals econding vse 7
of swell phage they experience with vari ‘Sitiaiiad ail iad
water content. chapirtinen aie Aneerebirr by rol All clays react to the = —— dips diccee™
Residential Slab and Footung Code. tes mele ee i ow Th tee i
varies considerably between different clays, as docs
Causes of Movement {rhe te er rng ay fo ee
. aie — petiods. Because of the low absorption and expulsion rate, this
There are two types of sextlement thar occur as a result of
construction:
* Immediate settlement occurs when a building Go Seas 0 Be
foundation soil, asa result of vasa hesd onde
weight of the structure. Ths coheloe neoity of Gey soso ten
against his, bur granular (particularly sandy) soil is
* Consolidation sectlement is a feature of clay soil and may take
place because of the expulsion of moisture from the soil or because
Phenomenon will not usually be noticeable unless there ate
rainy or dry periods, usually of weeks or months,
ing on the land and wil characteristics,
‘The swelling of soil creates an upward force on the footings of the
building, and shrinkage creates subsidence thet takes away the
support needed by the footing to retain equilibrium.
Shear failure
This occurs when the foundation sod does not have
ji penne papa undnepe sw sig! rol
two major post-construction causes:
* Reduction of lateral support of the sail under the fonting duc 10
of the soil’s lack of to focal comp or shear
This will ueually take during the first few months after
construction, bur has known to take many years in
exceptional cases, * Significant load increase.
Tiers pects be We Peete ead Se en ead Sees
of excavation.
into corsich as part off of the sie for
tion. Building nee tie ib eT 19) deals with these
problems,
© In clay soil, shear failure can be caused by saturation of the soil
adjacent to ot under the footing,
Foundation
Most sand and cock sites with litte or no ground movement from moisture changes
Slightly reactive clay sites with only slight ground movement from moisture changes
Moderately reactive clay oF silt sites, which can experience moderate ground movement from moisture changes
olsleketa lF
Highly reactive clay sites, which can experience high ground mavement from moisture changes
Extremely reactive sites, which can experience extreme ground movement from moisture changes
AwP Filled sites
to erosion; reactive sites subject co
r Sicca which inclade soft soi, such a sft cay of sit ot foour sands: lands mine wbpidence; collapsing soil: soils subject
whach cannot be classified otherwise
Page 20
‘Tree root ‘Trees and thar are allowed to grow in the vicinity of footings can cause foundation soil movement in two ways: © Roos that grow under footings may increase in cross-sectional size, exerting upward pressure on footings. * Roots in the vicinity of foocings will absorb much of the moisture in the foundation soil, causing shrinkage or subsidence. |Unevenness of Movement ‘The types of ground movement described above usually occur unevenly theoughout the building's foundation soil, Settlement due to construction tends to be unevei because of; © Differing compaction of foundation soil price tn construction, * Diffcring moisture consent of foundation soil prior to construction, Movement duc to non-constraction causes is usually more uneven still. Erosion can undermine a footing that traverses the flow or can create the conditions for shear failure by eroding soil adjacent to a footing that runs in the same digectian as the flow. Saturation of day foundation soil may occar where subfloor walls create a dam that makes water pond. It can aleo occur wherever there isa source of water near footings in clay soil. This leads to a severe reduction in che strength of the soil which may create local shear Seasonal swelling and shri of clay soll affects the perimerer of the first, then spreads to the interior, The swelling process Da pee pda i oron the weather ude where the land is flat, Swelling gradually reaches the i from unde footings sending to create subsidence of the part of the structure under which it occurs, Brickwork walls wall resist the stress created by this removal of poppet by Setting Dee So s until the bricks or the mortar bedding fail masonry has tesistance. Evidence of failure varies according to circumstances and sympeoms may include: * Seep cracking in the mortar beds in the body of the wall or sbore/below openings such as doors ot windows. * Vertical ing, in the bricks (usually but nor necessarily in line with the vertical beds or perpends). po pany Loy hata a ea pr rnponcps "sae sometimes rattling ornamenss etc. Seasonal foundation soll due w rainy periods first lifts the mest extremities of system, then the remainder of the seers 3 seer Siicrunkovest to lift internal swelling firs sends to create a dish effect, because the foonings are pushed higher than the internal ones the floor car be there visible: Seago he por age tea es As the moisnure completes its journey vo the innermost areas of the the internal footings will rise. If the spread of meisture is roughly even, it may be thar the will spontly teappees, ber ic a mare eter don be uneven. a difference rather in In with timber by bearers Doming and dishing are also affected by weather in ocher ways, In Movement caused by tree fn rooes will exert an preeure on footings, whereas iat ts detiag Nocmees twee of shrub roots will vend to remove support from footings by inducing shrinkage. caused by the structure itself ing where it can. It will attempt to ded foundat pet Jn the event of construction settlement, cracking will usually remain unchanged after the process of settlement has ceased. cracking will usually continue to develop wewil the origi cuts bas buen wovetied, or ell dhe ssbeidonce neutralised the affected portion of | and the structure has stabilised on other footings thar remain In the case of coer ee cee dani return to its original position: i a however it is more likely that the rotational effect will mot be exactly reversed, and it is also uswal that brickwork will sectle im its y r the problem. This means always the case, ree ofcneke hockeeed teen aaa eager oe seriously. Upheaval caused by
Page 21
Sern sodteopet hans kao nd he maf cases, it is internally visible cracking that should be the main focus of attention, however there are a few examples of dwellings whose external leaf of masoary preroens oto be checked i there any dawbe. In any cate, externally vxble is imp: asa guide to on the structure and it should also be remembered chat the external walls must be ling, themselves, ity * Corroded guttering or downpipes can spill water to ground. . positively connected to a proper stormveater Seach spun AL Oaser a coacenidnn or shal ws yal des ilmenite Scant alpen chai —— bu posed meee masonry walls is a cosmetic ‘sand ky mero ele he below is a reproduction of AS 2870. AS 2870 also publishes sal ee oes coe Lyis abe thie be Prevention/Cure Plumbing ‘Where building mavement is caused by water service, luenbieeg, pebenypapraen dant wo epee Auriga a Ic is prudent, however, Serene in the case of upheaval. It should be noted, however, that where the building where possible, Seefapepe. vd ed buildings are Lay say rings ae 6 sale coset Ig il mde ater bai of brickwork and ly walls are the 2 Bae opond an vanes ee supporting structure for the bai Tn this case, the subth masonry walls can be expected to as Full brickwork walls. = eee ay situated directly under the thar are ii wo charge went ere pera rbeTa A bilding fs the wath the ecole dat wie Set the tap suay ener dn barked tonnah trench that houses the sewer piping, If the erench has been poorly see ti ln ig sa Sapa ink ne Os eminel wal ine backfilled, the water will cher pond or flow along the bottom of walls, depending on i ‘eam: tennbhes uneall footings Gaines hupenln thoes s tenal ween thar the As these ro the me | Water Service ond Drainage ‘Where a waver service pipe, a sewer or sormwater drainage isin the vicinity of a building, a water leak can cause erosion, or leakage and trench flows also encourage tree and shruby Seen te nisearune caquams uaoeeneey a roof result in volumes of | Watheco nak ss 5 large rainwater being 9 cence ORES fom ine ene RS ee paners blocked with can be at a similar depth, it is not hard to see any water that is thus directed into a trench ean casily affect the foundation's ability to support footings or even gain entry to the subfloor area. Ground drainage In all soils there is the capacity for water to travel on the surface and below it, Surface water flows can be esablished by inspection during. and after heavy or produnged rain. If necessary, a grated drain syseem Se Oa ete ee ee y when Sous igeolen Sar coring ke ciel soca Conlon coon pape tee ee ner ‘This subject ix referred to in BTF 19 may properly be regarded as an area for an expert consultant. Protection of the building ee a a eo shrubs and trees causes sone sacks wae cies sre pcblomst For this reason, particularly where problems exist or are eo icra: le tocnbeasendld tan Un spvoe Of patieg be locale aed around as much of the building perimeter as necessary. This paving CLASSIFICATION OF DAMAGE WITH REFERENCE TO WALLS of and crack width Description of typical damage and required repair naoniee Damage Hairline cracks <0,1 mm o Fine cracks which do not need repair <i mm 1 Cracks noticeable but easily filled. Doors and windows stick slightly <5 mm 2 enero ant Peary ene eee 5+15 mm (or a number of cracks 3 to be replaced. Lm 3 mm of more in one group) Wearhenightness often: Extensive work breaking-out and replacing sections of walls, 15-25 mm but also depend 4 setae ‘Window and door frames distort. Walls lean on number of cracks or bulge noticeably, some lox of bearing in beams. Service pipes disrupted
Page 22
‘Shrubs
2
x for
from house
_—. Drained
Carport Pathway
Path: |
a
mulch
should extend outwards a minimum of 900 men (move in highly
reactive soil) and should have a minimum fall away from the
building of 1:60. The finished paving should be no less than 100
mm brick went bases.
te is to relocate drainage away from this paving, if
a mene Le ban ines this i not
, earthenware pipes should be replaced by I'VC and
should be of the same soil type as the surrounding soil
and compacted to the same density.
Except in areas where freezing of waser is an issue, ic is wise to
temove caps in che building area and relocate them well away from
the building ~ preferably not uphill from it (see BT'F 19).
It may be desirable to install a grated drain at the outside edge of rhe
paving on che uphill side of the building. If subsoil drainage
needed this can be installed under the surface drain.
Condensation
In buildings with a subfloor void sach as where bearers and joists
support floor: ventilation creates ideal conditions for
condensation,
floor and the ground.
Warming: Although this Balding Technology Ble deals with
cracking im buildings, it should be said chat subfloor moi
SS hinid«ubiaa:
© Water that is transmitted ineo masonry, mesal or timber building
elements causes damage and/or decay to those clements.
* High subfloor humidity and moisture content create an ideal
environment for various pests, including termises and spiders.
© Where high moisture levels are transmitted to the flooring and
walls, an increase in the dust mite count can ensue within the
living areas. Dust mives, as well as dam in general, can be a
Where isolared footings rise and Fall because of swell/shrink effect.
the homeowner may be tempted co alicviate floor bounce by filling
This BTF was prepored by John Lewer FAIB, MIAMA, Partner,
Construction Diagnosis.
The informabon in the and other Issues in the series wus decwed fon vancUS Sources and mas beleved to ba conmet when puttisned.
‘The information Is actor fim provided In good faith and not claimed to be a exhaustive
Further professions! advice oaeds to be ottmred belove hing ary acton based on the
Ovstibuted by
CSIRO PUBLISHING PO Box 1139, Collingwood 3066, Australia
Freecall 1800 645 05! Tel (09) 9662 7664 Fax {03} 9662 7555 www:publish csivo.ow
‘Email: putdaring saies@coro au
© CSIRO 2003. Unauthonsed copying of this Bulging Technology Me « prohibited
Page 23
Ground Drill Pty Ltd PH - 0407035220
ATF The Bennett Family Trust W - www.grounddrill.com.au
ABN - 15204820396 E - [email protected]
QBCC Lic – 15034580 Cedar Pocket QLD 4570
Effluent Disposal Report
Job No: 22/224
Date: 16/06/22
Client: Bliss Homes & Renovations
Site Address: Lot 8 Hinterland Close, Tinbeerwah
Proposed Structure: Proposed Residence
Information Provided by the Client: Plans
Local Authority: Noosa Shire Council
Page 24
Introduction
The purpose of this report is to evaluate and design a suitable on-site treatment system and disposal
area in accordance with AS 1547 – 2012, the Queensland Plumbing and Wastewater Code, the
Plumbing and Drainage Act, The Environmental Protection Act & Local Authority requirements.
The report relates exclusively to the above site and the proposed and or existing buildings shown on
the plan only. All measurements and levels shown are as accurate as possible with the information
provided these are to be used for locating the onsite effluent disposal system only.
Site Description
Weather Conditions Fine
Slope 27-30%
Slope Stability To be address in slope stability report
Vegetation Grassed, scattered large gums
Fill Nil
Flooding Nil
Watercourses Gully downhill well away
Site exposure Sun & wind
Salinity Nil
Surface condition Nil cracks, seepage or compaction
Boulders & Rock outcrops Nil
Will water from uphill traverse the area Yes, diversion drain to prevent
Water table Nil
Soil Category (AS1547-2012 Table M1)
Borehole 0-0.3m 0.3-0.9m
BH3-BH5 Cat 4 Cat 5
Clay Loams Light Clays
Weakly Structured Moderately Structured
0.12-0.5m/d 0.06-0.12m/d
Recommended Design Irrigation Rate
Test Result 0.09
Recommended Design Irrigation Rate 3mm/day
Adopted Rate 3/mm/day
Calculations
Bedrooms 4
Persons 6
DIR (mm/day) 3
Litres per person per day (Tank supply) 120
Calculations 6x120=720 /3= 240
Disposal Area Required 240m2 Heavy Droplet Surface Irrigation
Page 25
Risk Assessment
Risk Risk Mitigation
Surface Runoff Diversion Drain & mound
Human Contact Signs and mound to identify area. Apply by
setbacks
Overloading of system and LAA Use correct DIR, flow allowances and
maximum occupancy
Performance Solution
• The design has considered site and soil conditions and has also been discussed with the
landowner.
• Irrigation area has been designed using correct DIR.
• The spray from the sprinklers shall not exceed 500mm in height, 2000mm in dia. (1m
throw) and be heavy droplet in nature that prevents misting and drift. Control valves may be
needed to adjust the flow and pressure to achieve this.
• All pipework and materials used are to be new, meet relevant standards and be fit for use.
• Category 4 soils or better will assist in even distribution of treated effluent.
Page 26
Recommendations
Treatment
An approved Advanced Secondary ASTP is to be installed.
(System must be approved by QLD Depart of Housing & Public Works)
• Installer to ensure tank position does not damage to existing or proposed structures and does
not cause audible disturbance to nearby residences once final site plan and earthworks are
known. (Tank position on plan is indicative, final positioning to be nominated by installer)
• The tank must be installed and anchored, if necessary, to prevent flotation.
Installer to confirm sufficient fall is available to the treatment plant prior to installation once
the floor height is known.
• Top of treatment plant shall be at least 150mm above any flood levels that are present.
• A filter must be installed in between treatment plant and irrigation area
• Pump must have sufficient power to pressurise the irrigation area, controls valves may be
necessary on the irrigation lines to restrict flow to prevent sprays misting or drifting outside
the designated land application area.
• Two signs are to be erected stating “Effluent Water, Avoid Contact, Do not drink”
• Flexible joints should be used from the treatment to the proposed/existing structure where
the site is “H1” or higher.
Irrigation Area
A 240sqm fixed surface irrigation area consisting of fixed heavy droplet sprinklers
300mm high and a maximum spray diameter of 2m and height of 0.5m. (see plan)
• All pipework and fittings used must meet relevant Australian Standards be buried, withstand
150% of pump shut-off-head and be fit for use.
• A K-rain valve is to be installed to evenly distribute effluent.
• The supply line from the treatment plant to the irrigation area shall be buried 25-32mm
purple line poly within a 200mm layer sand bed to prevent damage.
• The area is to be installed in a way that creates no pooling or runoff.
• The installer is to install non return valves if necessary to evenly distribute effluent and
prevent back to the treatment plant.
• A reserve area equal to the above area is available.
Page 27
Diversion and Vegetation Requirements
• The area is to have a shallow diversion drain or mound uphill of the area to divert surface
water around the area.
• The irrigation area is to be mulched to a depth of 150mm and densely planted out with
nitrogen and water tolerant plants.
• The area is to be surrounded by a 150mm earth mound
• All Storm water from the residence and uphill slopes is to be diverted away from the area.
Setbacks
The below minimum setbacks must be complied with when installing the system. Greater
setbacks may be stipulated on the plan due to site and soil conditions.
(Advanced Secondary)
Surface & Covered Surface Irrigation
10M from a watercourse, dam, table drain, bore etc.
10M from a dwelling or habitable building or recreation area.
2M from a boundary/driveway if it slopes away or is level with that boundary/driveway.
4M from boundary/driveway if it slopes towards that boundary/driveway
6M from an inground water tank
6M from pool edge.
Maintenance, usage, and installation notes
The installer, builder and homeowner should families themselves with the below.
• Scrape all dishes to remove fats, grease, etc. before washing
• Don't use a garbage grinder
• Use biodegradable soaps
• Use a low-phosphorus detergent, don't use powerful bleaches
• Don't put sanitary napkins and other hygiene products into the system
• Spray or irrigation areas should have access restricted
• Divert surface water away from land application area
• No vehicles or stock should be allowed on trenches, beds or irrigation area.
• Deep rooting trees or shrubs should not be grown over absorption trenches or pipes
• Vegetable gardens and/or fruit trees should not be planted within or near area, where there
is a possibility of airborne spray coming into contact with the plant.
• Structures should not be constructed near areas that encourage people to congregate.
• Play areas and equipment should be well away from areas where there is no possibility of
spray coming into contact with humans.
• Treatment plants and septic tanks are to be desludged every 3-5 years.
• If any part of this design is unclear, please call before buying products or installing.
• This report must be approved by the local authority and appropriate permits issued before
any works can be undertaken.
• Installer is to contact local council prior to burying the system for a site inspection and
certification.
• Follow the manufacturer's instructions, relevant codes, standards and guidelines for
installation, servicing, maintaining and cleaning the system and irrigation
area/trenches/beds.
• The Treatment Plant is to be placed on an approved service schedule
Page 28
Limitations of Report & Notes
This report is based on information gathered from the field investigation and information
provided by the client if any. Ground Drill should be notified immediately if ground
conditions are found to differ from this report.
Unless otherwise stated this report does not address the following issues;
• Mining Subsidence.
• Slope Stability (If the site is in a known slip area or is steep, it is recommended that a
Geotechnical Engineer be engaged to conduct a Slope Stability assessment).
• Deep soft or settling soils
• Soil Contamination, hazardous materials and or acid sulphate.
• Any slopes, dimensions, levels, site features or plans in this report are approximate only
show approximate testing locations.
• Flood levels (It is the client’s responsibility to inform us of any flood levels on the
allotment).
• If water is found in the boreholes this depth may vary greatly over time. This report does not
address the influence any natural springs may have on the structure.
• It is the client’s responsibility to inform us of any nearby underground services that have
been or will be installed near the proposed area.
• Earthworks could affect the design.
• If any fill is placed on the allotment post investigation this could change the design.
• Surface water is to be diverted away from the area.
• This investigation undertaken consisted of the occluded boreholes/test pits, given the size of
the site it is possible that a problem could have been missed. eg. Filled dam/gully, soft soils,
fill, springs, boulders, rock etc. We cannot give a definitive assurance that none of these
problems exist on the site unless we did a greater number of boreholes which would be
uneconomical and impractical.
• Ground Drill will not be liable for any Council Inspection, submission or reviewing fees due
to changes in report or plan requested by client or Council.
• No allowance has been made for spa baths
Authorised Signatory
Matthew Bennett
on behalf of Ground Drill Pty Ltd
QBCC Lic # 15034580
Page 29
Soil Profiles
BH 3 Soil Description BH 4 Soil Description BH 5 Soil Description
0 GRAVELLY SILTY SAND (SM) – 0 GRAVELLY SILTY SAND (SM) – 0 GRAVELLY SILTY SAND (SM) –
Fine to medium, brown, fine to Fine to medium, brown, fine to Fine to medium, brown, fine to
medium gravel, dry, loose. medium gravel, dry, loose. medium gravel, dry, loose.
100 100 100
200 200 200
300 SANDY CLAY (CH) – High 300 SANDY CLAY (CH) – High 300 SANDY CLAY (CH) – High
plasticity, orange mottled grey, fine to plasticity, orange mottled grey, fine plasticity, orange mottled grey, fine to
medium sand, trace fine to medium to medium sand, trace fine to medium sand, trace fine to medium
gravel, moist, stiff. medium gravel, moist, stiff. gravel, moist, stiff.
400 400 400
500 500 500
600 600 600
700 700 700
800 800 800
900 DISTINCTLY WEATHERED ROCK 900 DISTINCTLY WEATHERED 900 DISTINCTLY WEATHERED ROCK
(DW) – Fine, pale brown, dry, low ROCK (DW) – Fine, pale brown, (DW) – Fine, pale brown, dry, low
strength rock. dry, low strength rock. strength rock.
1000 Auger Refusal 1000 Auger Refusal 1000 Auger Refusal
1100 1100 1100
1200 1200 1200
1300 1300 1300
1400 1400 1400
1500 1500 1500
Site Photo
Page 30
Fixed sprinklers
(Max plume height 500mm
150m earth mound (Max. plume throw 2m dia.)
K-Rain 25mm purpleline poly
Valve
1.5m
20m
1m 3m 3m
12m
Fixed Sprinkler layout Ground Drill Pty Ltd
See site plan for location. Sunshine Coast, QLD.
NTS QBCC # 150 345 80 C:\Users\Ground Drill Desktop\Documents\Advertising\print\logo.jpg
E: [email protected]
W: www.grounddrill.com.au
P: 0407 035 220
Page 31
Notes
Levels shown are
approximate and are sourced
from local council mapping
or information provided by N
the client. These levels are
solely to demonstrate the
functionality of the system. Proposed Fixed Surface
Actual floor height is to be Irrigation Area - 240sqm
confirmed with the builder (12 x 20m)
prior to installation. (Approx RL 119)
All pipe work from the
structure to the proposed
system should be covered
and adequately vented and
be vermin/insect proof.
All work carried out should
meet relevant
codes/standards and be done
by an appropriately qualified BH4
BH5
and licensed person. PT2
PT3
Proposed system should be
constructed in a way to
maximize evapotranspiration
and minimize potential
pooling and runoff. 2m
If plans were not available at
BH3 Proposed Advanced
the time of investigation
PT1 Secondary ASTP
further reporting and design
Reserve Area (Approx RL 126)
work may be needed prior to
council submission and
installation.
Care is to be taken not to
compact,smear or damage
the soil structure during
20m
installation (This can lead to
premature failure).
Slope 27-30%
If structures have been built
since our initial investigation
(Including neighboring
structures) please contact us Proposed Residence
to confirm this will not (Approx RL 130)
adversely effect the design.
Final landscaping and
82
installation should discourage
m
and limit causal pedestrian
Ap
access.(By way of plantings, BH2 BH1
pro
border, mounds, visual and
x.
or physical deterrents)
The owner should obtain
knowledge on how to use
and maintain the proposed
system. Most of this is
available from your chosen Typical Fixed Surface Installation (NTS)
supplier/installer.
Heavy
This report must be
Droplet
approved by the local council
Sprinkler
prior to any work
commencing.
The effluent disposal
report must be
accompanied by a Site
Classification Report. If
300mm
the Site Classification is
H1,H2, E or P an
articulation joint will need
to be designed by a
person licensed to do so.
Client- Bliss Homes & Renovations
Site - Lot 8 Hinterland Close, Tinbeerwah
Ground Drill Pty Ltd
Date - 16/06/22
Abbreviations Sunshine Coast, QLD.
Job# - 22/224
BH : Borehole DCP : Dynamic Cone Penetrometer QBCC # 150 345 80
Scale - 1 : 750 @ A4 (Site features are approximate-Do not scale)
PT : Percolation Test HD : Heavy Droplet Lilac Sprinkler E: [email protected]
TV : Turf Valve RWT : Rain Water Tank W: www.grounddrill.com.au
P: 0407 035 220
Page 32
ABN 51 640 311 842
arcosgroup.com.au
Sunshine Coast | Brisbane | Gold Coast
Contact Us
07 5293 7648
@arcosgroup
[email protected]
arcosgroup.com.au
Sunshine Coast | Brisbane | Gold Coast