Geotech Inestigation · MCU22/0192

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

Lot 199 SP233184 (*79) Gympie Kin Kin Road, Kin Kin.
(GPS coordinates 26°15’35"s, 152°52’48"e),

for the four proposed one-bedroom cabins on this 38 hectare allotment.

Our site investigation fieldwork was performed on 8/08/2022 after some 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 Methods of testing soils for engineering purposes,

AS 2870 Residential Slabs and Footings,

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

 

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 022-164

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SITE INVESTIGATION

As with all site investigations we assume 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 and at each stage as these
factors are 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, and

the collation and evaluation of the results from the above studies.

BB Ge Se G

(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;
30 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 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 022-164

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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 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 interface 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.
However, experience in this area has shown that beneath any floaters the soil grades
into stable weathered rock at relatively shallow depths.

Moderately weathered excavatable rock was encountered at, and is expected at,
relatively shallow depths across the proposed site.

Cabin 4 (existing dwelling)

The proposed site for Cabin 1 is on a partially exposed 0-3% eastern slope with
neighbouring vegetation consisting of grasses and trees. We recorded a few
shrubs/small trees within, or adjacent to, the proposed cabin site that are likely to be
removed. Slope configuration across the proposed site is determined to be linear
planar. The landform was recorded as natural and partially disturbed.

Cabins 1,2 &3

The proposed site for Cabins 2, 3 & 4 are on an exposed 15-30% northwestern slope
with neighbouring vegetation consisting of grasses. Slope configuration across the
proposed site is determined to be waxing planar. The landform was recorded as
natural and partially disturbed.

The resistance of the soil 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 022-164

Page 5

The samples hand collected and classified on site from BH 2 at a depth of 600 mm
and BH 4 at a depth of 600 mm below the existing surface level returned a linear
shrinkage result of 12.6%.

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

 

Ys Value = 21 mm

 

 

 

 

 

 

 

 

 

 

 

 

 

Predicted Surface Movement Class
Ys= < 20mm S
Ys =>20-< 40 mm M
Ys => 40-< 60 Hl
Ys => 60 ~e 75 mm 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: 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 022-164

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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.

5 Site Investigation Report 022-164

 

Page 7

 

 

This footing is founded
above the critical depth

4 _
Ground/pad level ee

a
| |

 

unstable line and is deemed to
eel [ —j be unstable.
Ng,
Lie,
Voy,
stable NG i
Le Piers must be excavated

to below the critical depth
N line to provide stability to
these footings.

th

This footing is founded
below critical line and

 

 

 

Any proposed or existing excavation. The
builder must ensure all excavations are
discovered and the footing and slab is
secured below the critical line accordingly.
This should include a search of all council
& other records for as constructed plans to
establish excavation depths & widths.

Yo

 

 

 

 

 

 

 

is stable
ZN...
~“.,
“.
a
i‘ Q
30 degrees .,
se TRS Ts
Horizontal (“6ferelay) N.S E
S
Critical Depth line measured from deepest In the case of a buried pipe the
point of the excavation nearest the footing. invert level is usually above and
away from the nearest corner
of the excavation.
Critical Depth Line
X
Unearthed Geotechnical P/L. 6 Site Investigation Report 022-164

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Lot 199 (*79) GYMPIE KIN KIN ROAD, KIN KIN. 022-164

 

Proposed Cabins Site.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Borehole No 1 (Cabin 1) p D p Borehole No 2 (Cabin 2)
v.Clayey Silty Gravelly Sand SC 3 100 v.Clayey Silty Gravelly Sand SC
(Dark Grey Brown) (Dark Grey Brown)
Moist & Disturbed 2 | 200 Moist & Disturbed
Sandy Gravelly Clay CI/MP 3 | 300 Sandy Gravelly Clay CI/MP
(Orange Brown Mottled) 2 400 (Orange Brown Mottled)
Moist & Stiff 3 | 500 Moist & Stiff

4 600 ~ (0.032 = Iss, Ls = 12.6%) ~
4 | 700
5 | 800
(Friable Weathered Rock Lenses) 7 900 (Friable Weathered Rock Lenses)
10 | Im
UTP Hand Auger 15+ | 1100 UTP Hand Auger
(Distinctly Weathered Rock DW) 1200 (Distinctly Weathered Rock DW)
1300

 

 

 

 

 

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

 

 

 

UNEARTHED GEOTECHNICAL P/L. PO Box 1204, GYMPIE. Q 4570. 8/08/2022

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Borehole No 3 (Cabin 3) p_ | Depth
v.Clayey Silty Gravelly Sand SC 2 100
(Dark Grey Brown)
Moist & Disturbed 3 200
Sandy Gravelly Clay CI/MP 2 300
(Orange Brown Mottled) 3 400
Moist & Stiff 4 500
4 600
5 700
7 800
(Friable Weathered Rock Lenses) 9 900
15 lm
UTP Hand Auger 1100
(Distinctly Weathered Rock DW) 1200
1300
UTP = Unable to penetrate.

 

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.

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                                                                                                               ,--
                                                                                                                               EXISTING
                                                                                                         �

                                           LARGE PROMINENT TREES




                                                 PROPOSED DEVELOPMENT
                                                 SITE (CABINS 1,2,3)




    - - ,_,
   100            0            100
                                I

                        SCALE I : 5000

CLIENT: ANTHONY McDONOUGH (0407 493 611)
                                              200
                                               I
                                                           300 M
                                                             I
                                                                     \\synology\General\JO BS\022-164-GympieKin Kin\022-164-Drawings.dwg

                                                                                     8/08/2022
                                                                                                           COPYRIGHT: THESE PLANS ARE THE PROPERTY OF
                                                                                                           UNEARTHED GEOTECHNICAL AND SHALL NOT BE COPIED
                                                                                                           OR REPRODUCED WITHOUT THE APPROVAL OF
                                                                                                           UNEARTHED GEOTECHNICAL.

         LOT 199 SP233184 (199) GYMPIE KIN KIN ROAD,
                                                          ORIG. SHEET SIZE: A4
        K IN_K _IN_._N_O_O_S_A_C_O_U_N_C_IL_. -----------1SCALE: 1 :5000
_______ _
                             UNEARTHED GEOTECHNICAL P/L
A.J. TRELOAR QBCC Lie. No. 740251    PO Box 1204, GYMPIE, QLD 4570 0417 132 300   [email protected] PLAN No.                    022-164

Page 10

 

 

 

SCALE | : 500

as

\\synology\General\JOBS\022-164-GympieKinKin\022-164-Drawings.dwg

 

CLIENT: ANTHONY McDoNouGH (0407 493 6lI) 8/08/2022

 

Lot 199 SP233184 (199) GYMPIE KIN KIN ROAD,
KIN KIN. NoosA COUNCIL.

COPYRIGHT: THESE PLANS ARE THE PROPERTY OF
Une ary yT BE COPIED

  

 

ORIG. SHEET SIZE: A&

 

 

UNEARTHED GEOTECHNICAL P/L

A.J. TRELOAR QBCC Lic_No.74025|_ PO Box 1204, GYMPIE, QLD 4570 0417 152 300 [email protected]. AU

 

SCALE: 1:500

 

 

PLAN No. 022-164

 

 

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