geotechnical report

Page 2

INTRODUCTION
Unearthed Geotechnical P/L was commissioned to undertake a Site Investigation
Noosa Council at

Lot 2 SP241381 Sister Tree Creek Road, Kin Kin.
(GPS coordinates 26°14’37"s, 152°51°35"e),

for the proposed cabins on this 21.4 hectare rural allotment.

A representative of Unearthed Geotechnical P/L was met and shown to the proposed
site by the owner, J Williams.

Our site investigation fieldwork was performed on 31/01/2022 after some recent
seasonal storm/rain activity in the course of the preceding weeks.

This report does not include an assessment of slope stability or landslide risk.

The standards and references used in compiling or referred to in this report are,
The Queensland Building & Construction Commission,

AS 1289-2014 Methods of testing soils for engineering purposes,

AS 2870-2011 Residential Slabs and Footings,

AS 3798-2007 Guidelines earthworks commercial & residential developments,
AS 1726-2017 Geotechnical Site Investigations.

 

COPYRIG.

Copyright in the whole and every part of the drawings, specifications and other
documents provided by Unearthed Geotechnical P/L remain the property of the
Unearthed Geotechnical P/L. Upon receipt of full payment for our service the client
is licensed to use the drawings, specifications and other documents for the work/s for
which they were commissioned. They shall not be used for any other work except by
agreement with Unearthed Geotechnical P/L.

 

Unearthed Geotechnical P/L. 1 Site Investigation Report 022-003

Page 3

SITE INVESTIGATION

As with all site investigations we assume that the fundamental principles of good
developmental construction, earthworks or such were not overlooked, and were
carried out with the consistent application of ‘best practice’ techniques at each stage
as these factors are of great consequence. We also presuppose that the fundamental
principles of good construction will not be overlooked, and will be carried out with
the consistent application of ‘best practice’ techniques across the site as these factors
are also of great consequence.

The fieldwork undertaken for our site investigation included the following;

detailed subsoil investigation recording characteristics and limitations,

a comprehensive site assessment to record topography, geography and geology,
soil observation boreholes (75-100 mm dia. Jarret style hand augers),
penetrometer testing with 9kg Dynamic Cone Penetrometer (DCP),
classification and testing of hand collected soil samples.

Se GG GB &

(The test locations were not professionally surveyed and should be considered approximate)
(All fieldwork performed in accordance with the relevant Australian Standards and Codes)
(All boreholes backfilled in accordance with Occupational Health and Safety regulations)

FIELD TEST LIMITATIONS

The soil profiles reported should generally be representative of the soil conditions across this
site. In some cases soil conditions can change dramatically, and can change over short
distances. If site works reveal soil conditions that are different from those shown in the
attached data, the evaluator must be informed immediately as changes may be necessary.

CLIENT SUPPLIED INFORMATION

This site investigation and classification has been undertaken in accordance with AS
2870 ‘Residential Slabs and Footings'' The Queensland Building & Construction
Commission's (QBCC) 'Rectification of Building Work Policy’ has a requirement for
the following information to be supplied to us, and that we consider this information
in determining the site classification. This information includes, but is not limited to;
Property description and site address,

Evidence to ensure site is correct (e.g. Survey Plan, Registered Plan, etc),

Survey plan delineating contours, trees, existing developments, etc,

Land searches, including such information as flood lines, easements, covenants,
underground services and infrastructure, etc,

Any previous geotechnical work, e.g. original contour survey, and the limits of
prior subdivisional or developmental cutting and filling, service lines etc.

The known extent of further developmental or construction earthworks

Se Be Se

Se

Be

In this instance and at the time of our commission, we have considered the
information supplied to us by the client. Should the client or his agent have omitted to
supply us with the QBCC required information or supplied us with incorrect
information our assessment may be irrelevant and/or inappropriate. However, should
this information become available we would be pleased to amend our report
accordingly, if, and as necessary. We do not take responsibility for the consequences
in such cases and may incur additional costs if as a result; more testing or re-writing
is necessary.

 

Unearthed Geotechnical P/L. 2 Site Investigation Report 022-003

Page 4

FINDINGS

All the field information and test results collected during our site investigation and
detailed in this report, including any site plans, log and data sheets together form the
basis of our recommendations.

The soil profile encountered during our investigations, and as reported, was
reasonably and acceptably consistent across the proposed development, and within
our expectations from regional experience and correlation with The Qld Dept of
Mines/Energy Geology Sheet 9445/1999 (Gympie).

The Qld Dept Mines/Energy Geology Sheet 9445/1999 describes the geology as
Early-Middle Triassic, Kin Kin Beds, arenite, argillite or phyllite.

The proposed cabins site is on a large near level cut/fill pad with neighbouring
vegetation consisting of grasses.

Slope configuration across the proposed site is determined to be linear planar.
Slope stability problems were not evident during our investigations.

The susceptibility to flooding from groundwater is low and site drainage was recorded
as poor.

No water table was encountered on the day of our site investigation. However, during
and for some time after periods of seasonal, heavy or extended rainfall water seepage
on the sand/clay and fill/natural interfaces may cause a loss of bearing capacity at this
level. Seepage may also cause collapse of excavations, which may increase concrete
volumes significantly above those normally anticipated.

Cobbles and/or boulders in soil profiles are sometimes common and unfortunately we
cannot predict their size or frequency. It has also been our experience that these
floaters can be extremely difficult to excavate with conventional equipment.

Fill, which we have described as uncontrolled was encountered to the following
depths, BH 1 to 600 mm, BH 2 to 700 mm, BH 3 to 600 mm, and BH 4 to 1400mm.

At the time of writing this report we were unable to describe the fill as controlled.
This can be revised if, in the unlikely event documentation is available indicating that
this fill has been compacted and certified in accordance with AS3798-2007.

The resistance of the fill and natural soil profile encountered was tested with an
approved 9kg Dynamic Cone Penetrometer and the results recorded at the appropriate
levels on the attached log sections.

 

Unearthed Geotechnical P/L. 3 Site Investigation Report 022-003

Page 5

The sample hand collected and classified on site from BH 1 at a depth of 1100 mm
below the existing surface level returned a linear shrinkage result of 10.6%.

The expected surface movement (Ys) of the natural soil profile, due to seasonal
moisture changes in the soil encountered, is as follows

 

Ys Value = 25mm

 

 

 

 

 

 

 

 

 

 

 

 

 

Predicted Surface Movement Class
Ys=< 20mm S
Ys=>20-—< 40mm M
Ys => 40-< 60 mm Hl
Ys =>60-—< 75mm H2
Ys=>75 mm E
Problem sites P

 

Note: The proximity of trees and their effect on foundations should be considered when
determining specific engineering assessments, and for foundation/footing design.
Appendix B of AS 2870-2011 indicates that to reduce, but not eliminate, the possibility of
damage to the footings, trees should be restricted to the following distance from the
building (where rows or groups of trees are present the distance nominated below must
be increased, and similarly the Ys Value listed above may need to be increased) : 75% of
the mature tree height, for class “M” sites, 100% of the mature tree height, for class
“H 1” sites, and 150% of the mature tree height, for class “E” sites.

Note: Problem (P) sites are normally classified because of limited bearing strengths
at normal footing depths. In this instance be aware of the depth of the fill on the near
level cut fill pad and the effects of differential surface movements.

Note: This classification above has been derived from test work performed on the soil
profile encountered on the day of our fieldwork. Any further filling of the site or
excavation into the soil profile, may result in a different classification.

Temporary Excavations.

Where temporary excavations are performed for footing or services up to 600mm
deep, natural soils may have minor or no stability problems, however deeper
excavations have a possibility of collapse more readily and shoring of vertical
excavation may be required. Where an existing excavation has been filled with
uncontrolled fill, all locations above a line 30 degrees for sands and 45 degrees for
clays above the horizontal may be unstable and may not support any structure — see
attached critical depth line diagram.

 

Unearthed Geotechnical P/L. 4 Site Investigation Report 022-003

Page 6

LEGEND

 

Soil description (AS1726 — The Geotechnical

Site Investigation Code)

 

GW -— Well graded gravels, little or no fines

GP — Poorly graded gravels, little or no fines

 

GM - Silty gravels

GC — Clayey gravels

 

SW — Well graded sands, little or no fines

SP — Poorly graded sands, little or no fines

 

SM - Silty sands

SC — Clayey sands

 

ML — Inorganic silts and very fine sands

OL — Organic silts and organic silty clays

 

CL — Inorganic clays of low plasticity

CI — Inorganic clays of medium plasticity

 

CH — Inorganic clays of high plasticity

OH — Organic clays medium/high plasticity

 

Pt — Peat and other highly organic material

 

Ls — Linear Shrinkage %

 

Note

The stratifications identified on our log sheets are representative of the approximate boundary
between soil types and the transition may be gradual and vary over the site.

 

 

Abbreviations

 

Dk — Dark, Lt—Light, Gy -— Grey, Rd — Red

, Br—Brown, Or — Orange, Mott — Mottled.

 

LP, MP, HP - Low, Medium, High Plasticity.

SW - Slightly Weathered Rock.

 

P (p) — blows/100 mm approved penetrometer

DW - Distinctly Weathered Rock.

 

UTP — Unable to penetrate

 

EW - Extremely Weathered Rock.

 

 

Cohesive Soil Strengths approximate safe bearing capacities for clay-based soils.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Very soft (VS) —<25 kPa Soft (S) — 25 to 50 kPa Firm (F) — 50 to 100 kPa
Stiff (St) — 100 to 200 kPa Very Stiff (VSt) — 200 to 400 kPa Hard (H) — 400+ kPa
Soil Strengths Sands and Gravels
Density SPT “N” value Relative Density (%)
Very Loose (VL) <4 <15
Loose (L) 4-10 15-35
Medium Dense (MD) 10 —30 35-65
Dense (D) 30-50 65 — 85
Very Dense (VD) >50 > 85
Particle Sizes. Prefix Range of Sizes (mm)
Boulder - > 200
Cobble - 63 — 200
Coarse 20-63
Gravel Medium 2-20
Fine 0.6 — 2.0
Coarse 0.2—0.6
Sand Medium 0.075 — 0.2
Fine 0.002 — 0.075
Clay < 0.002 .

 

 

 

Moisture Condition

 

 

 

 

 

Dry Looks and feels dry, clay soils are normally hard, powdery or friable.
Moist Feel cool, darkened in colour, no free water on hands when remoulding.
Wet Soils are weak, free water can occur; granular soils bind together, clay softened.

 

 

Unearthed Geotechnical P/L.

Site Investigation Report 022-003

 

Page 7

 

 

 

 

 

 

 

 

 

amma
eas Ground/pad level
This footing is founded
wa above the critical depth
unstable line and is deemed to
ve be unstable. Any proposed or existing excavation. The
builder must ensure all excavations are
X..0,
to, discovered and the footing and slab is
tal “Lo Secured below the critical line accordingly,
stable “Sou i, This should include a search of all council
Bin, Pers must beiexcavated. & other records for as constructed plans to
™., line to provide stability to establish excavation depths & widths.
This footing is founded Ss these footings.
below critical line and
is stable
ZN.
™~,,
N.,
™.
=" Q
30 degrees .
aa TRS TS
Horizontal (46 for clay) 4 RS 2

 

 

 

 

 

“ In the case of a buried pipe the
invert level is usually above and
away from the nearest corner
of the excavation.

Critical Depth line measured from deepest
point of the excavation nearest the footing.

Critical Depth Line

 

 

Unearthed Geotechnical P/L. 6 Site Investigation Report 022-003

Page 8

LoT 2 SISTER TREE CREEK ROAD, KIN KIN. 022-003

 

Proposed Cabins House Site on a near level cut fill pad.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Borehole No 1 (Cabin 1) p D p Borehole No 2 (Cabin 2)
FILL 2 | 100] 2 FILL
(Sand Clay Gravel Mix) 4 | 200 2 (Sand Clay Gravel Mix)
Moist & Uncontrolled 2 | 300 3 Moist & Uncontrolled
4 | 400 | 4
2 | 500} 3
3 | 600 | 2
v.Sandy Clay CI/MP 2 | 700 3
(Brown) ; 4 | 800 3 v.Sandy Clay CI/MP
Moist & Loose/Medium Dense (Brown)
Sandy Clay CI/MP 3 | 900 3 Moist & Loose/Medium Dense
(Orange Red Brown Mottled) 4 | Im 4 Sandy Clay CI/MP
~ (0.024 = Iss, Ls = 10.6%) ~ 5 | 1100] 5 (Orange Red Brown Mottled)
Moist & Firm 4 | 1200} 5 Moist & Firm
Becoming Stiff 5 | 1300] 5 Becoming Stiff
6 | 1400] 6
6 | 1500} 6
End Hand Auger 1600 End Hand Auger
1700
1800
1900
2m
2100

 

 

 

 

 

 

75-100 mm Jarret style Hand Augers.
p = blows/100mm - 9kg Dynamic Cone Penetrometer.

UNEARTHED GEOTECHNICAL P/L. PO Box 1204, GYMPIE. Q 4570. SI/01/2022

 

 

 

Note - All field information and test results collected during our site investigation and detailed in the
accompanying report, including any site plans, log and data sheets are only to be used for the purposes of this
report. No third party use of any part of this information is authorised without specific or written consent.

Page 9

Lot 2 (*342) SISTER TREE CREEK ROAD, KIN KIN.

022-005

 

Proposed Cabins House Site on a near level cut fill pad.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Borehole No 3 (Cabin 3) p D p Borehole No 4 (Cabin 4)
FILL 2 | 100 1 FILL
(Sand Clay Gravel Mix) 3 200 2 (Sand Clay Gravel Mix)
Moist & Uncontrolled 2 | 300 1 Moist & Uncontrolled
2 | 400 1
4 | 500 | 2
2 | 600 2
v.Sandy Clay CI/MP 3 | 700 3
‘Brown
Moist & Luo see/ediam Dense * | one 3
Sandy Clay CI/MP 3 | 900 4
(Orange Red Brown Mottled) 4 lm 3
Moist & Firm 5 [1100] 2
Becoming Stiff 5 [1200] 2
6 | 1300] 3
7 {1400| 3
6 | 1500] 4 v.Sandy Clay CI/MP
End Hand Auger 1600| 3 ; (Brown)
Moist & Loose/Medium Dense
1700] 4 Sandy Clay CI/MP
1800 | 5 (Orange Red Brown Mottled)
1900} 5 Moist & Firm
2m 6 Becoming Stiff
2100] 5
2200] 6
2300] 7
2400 | 7
2500 End Hand Auger

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

75-100 mm Jarret style Hand Augers.
P = blows/100mm - 9kg Dynamic Cone Penetrometer.

 

 

UNEARTHED GEOTECHNICAL P/L. PO Box 1204, GYMPIE. Q 4570.

SI/O1/2022

 

 

Note - All field information and test results collected during our site investigation and detailed in the
accompanying report, including any site plans, log and data sheets are only to be used for the purposes of this
report. No third party use of any part of this information is authorised without specific or written consent.

Page 10

 

    
   
   

KIN KIN CREEK

EXISTING/PROPOSED
DEVELOPMENT SITE

100 0 100 200 300M q| Ss
|
SCALE | : 5000 \\synology\General\JOBS\022-003-SisterTreeCreek\022-003-Drawings.dwg

CLIENT: JoDIE WILLIAMS (0488 569 020) 31/01/2022 tnearine Gavre

 

   

ERTY OF
(LL NOT BE COPIED
r

 

 

Lot 2 SP241381 SISTER TREE CREEK RD, oe

 

ORIG. SHEET SIZE: A4
KIN KIN. | NOOSA COUNCIL

 

 

SCALE: 1:5000
UNEARTHED GEOTECHNICAL P/L
A.J. TRELOAR QBCC Lic. No.740251 PO Box 1204, Gympie, QLD 4570 _O4I7 152 500 [email protected]| PLAN No. 022-005

 

 

 

 

Page 11

 

 

  
      
    
      
  
    

FILL
cece somacrr ras H
cuT | ~~ BH3
ce ws
INTERNAL PROPERTY FENCING ™

 

 

 

 

 

 

 

LIP OF FILL BATTER (APPROX.

EXISTING
DEPTH OF FILL 2000MM) SHEDS

LIP OF FILL BATTER (APPROX.
DEPTH OF FILL 1500MM)

 

 

 

 

 

 

 

 

20 lo 0 20 40 60M
eet rrr
SCALE | : 1000 . .
\\synology\General\JOBS\022-003-SisterTreeCreek\022-003-Drawings.dwg}
CLIENT: JoDIE WILLIAMS (0488 569 020) 31/01/2022 tieeaetnes SDoTEEMGcAl Ae gla er be ci
Lot 2 SP24138! SISTER TREE CREEK RD, ——_—
ORIG. SHEET SIZE: A&
KIN KIN. | NOOSA COUNCIL SCALE. 11000
UNEARTHED GEOTECHNICAL P/L 022-003
A.J. TRELOAR QBCC Lic, No.740251 PO Box 204, GYMPIE, QLD 4570 O4I7 132 300 [email protected]. au] PLAN NO. -