Council archive · source document
20220109 - 21236-002-Rev0 Maher Tce · OPW23/0182
Attached to the e-mail Operational Works Application OPW23/0182 - 21 Maher Tce, Sunshine Beach QLD 4567 (Email 3 of 4).
1 February 2023 Project No. 21236-002-Rev0 GV Emanuel Constructions Attention: Gary Emanuel Email: [email protected] ADDENDUM REPORT – ADDITIONAL GEOTECHNICAL INVESTIGATION 21 MAHER TERRACE, SUNSHINE BEACH Dear Gary, As requested, Tectonic has undertaken an additional geotechnical investigation to assess founding conditions for the proposed residence at 21 Maher Terrace, Sunshine Beach. An original geotechnical investigation and slope stability assessment was completed prior to the demolition of the previous structures (Ref. Tectonic Report No. 21236-001-Rev0, dated 16 July 2021). This addendum report presents the results of our additional investigation, together with superseding geotechnical advice for the footing system. Please note this report should be read in conjunction with the original Tectonic report. The additional investigation was undertaken in the presence and direction of an experienced geotechnical engineer on 9 January 2023. At that time, a contiguous pile wall had been constructed along the southern and eastern boundaries of the site, with excavations completed adjacent to the pile wall to the presumed lower floor level. It appeared that excavations ranged between about 2 m and 4 m deep, which exposed stiff residual clays, becoming very stiff to hard with depth, overlying extremely weathered (XW) materials. Text Figure 1 below illustrates site conditions at the time of the additional investigation. Text Figure 1: View of the subject site looking south-east (9 January 2023) As bulk excavations had been practically completed the additional investigation comprised two boreholes, designated BH3 and BH4, drilled at the southern and northern edges of the level building pad respectively. Boreholes were drilled using Tectonic’s 4WD mounted solid flight auger rig to depths between 2.6 m and 3.2 m below ground level (BGL). In-situ testing, using the dynamic cone penetrometer (DCP) method, was carried out from the ground surface and within each borehole. Pocket penetrometer testing was conducted on relatively undisturbed auger cuttings of cohesive materials. One standalone DCP test (designated DCP4) was also conducted centrally between the borehole locations. Tectonic Geotechnical Pty Ltd PO Box 899, Buderim, QLD 4556 Office: 07 5478 9016 Email: [email protected] www.tectonicgeo.com.au A.B.N. 83 165 727 828
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Page 2
GV Emanuel Constructions 21236-002-Rev0
1 February 2023
Borehole and DCP locations are shown in Figure 1 attached at the end of this report, with borehole and
DCP logs presented in Appendix A, together with explanatory notes. Borehole coordinates were recorded
using a handheld global positioning system (GPS).
The subsurface conditions encountered in boreholes BH3 and BH4 were relatively consistent summarised as
follows:
Fill (presumably uncontrolled) – comprising stiff sandy clay of medium plasticity to 0.2 m BGL,
then or from the ground surface
Residual Soils – stiff sandy clay of medium plasticity (borehole BH3 only) to 0.2 m BGL, then very
stiff (or stiffer) sandy clay of medium plasticity to depths between 1.7 m and 2.5 m BGL; overlying
XW Materials – mostly hard sandy clay of medium plasticity to the borehole termination depths.
Groundwater seepage was not encountered whilst solid flight augering, nor was any groundwater observed
emanating through the excavation face.
Subsurface conditions inferred from standalone DCP4, were generally consistent with the boreholes
comprising inferred stiff clays to 0.1 m BGL, then very stiff (or stiffer) clays with practical DCP refusal on
inferred hard clays or XW materials at 0.8 m BGL.
In general accordance with the original geotechnical report (Tectonic Ref. 21236-001-Rev0, dated 16 July
2021), we provide the following advice.
All footings must penetrate through any fill (existing or future) and unsuitable natural materials to found at
least 0.3 m into stiff (or stiffer) residual soils. Depending on the design loads, high level strip and pad
footings, or a stiffened raft slab, may be adopted for the proposed basement and development. An allowable
bearing pressure (ABP) of 100 kPa may be adopted for high level footing design where footings are founded
at least 0.3 m into stiff/medium dense (or stronger) residual soils.
Based on the subsurface conditions encountered in both boreholes and inferred from the central DCP, very
stiff (or stiffer) residual clays were encountered or inferred at depths of about 0.2 m BGL (levels at the time of
the investigation). Pocket penetrometer readings exceeded 300 kPa below these depths with DCP values
> 7 blows per 100 mm intervals. Therefore, high level footings founded at least 0.3 m into very stiff (or
stronger) residual soils, could be designed using an ABP of 300 kPa.
Should excessive column loads preclude the use high level footings, or in areas where unsuitable materials
(e.g. fill) are exposed at the design level, deeper piled footings would be required. Piles could be designed
based on the following ABPs:
0.5 m into very stiff to hard residual soils – ABP 400 kPa.
0.3 m into XW materials or very low strength sandstone – ABP 600 kPa.
It is recommended that all footings are inspected and assessed by a structural/geotechnical RPEQ prior to
pouring concrete. Resultant settlements from footings founded as described above should be within
serviceability limits, estimated to be less than 25 mm or 1% of footing width. It should be noted that over
dimensioned strip/pad footings may result in excessive settlements, which should be considered.
Footing design should also account for potential soil reactivity to be equivalent to Class M. It should be noted
that placement of reactive clay may result in a more severe equivalent site classification, such as H1 or
greater.
All footings should found such that they are not adversely affected by any adjacent excavations, trenches, or
retaining walls that are not designed to support building loads. Footings adjacent to any fill batter crests
should be deepened to found below the toe of the batter. Footings should found at least below a plane
extending 1 m horizontally from the base of trenches/excavations/retaining walls, then rising up at 1V:1H, as
illustrated in Text Figure 2 overleaf.
2/3
Page 3
GV Emanuel Constructions 21236-002-Rev0
1 February 2023
Text Figure 2: Footing depth required to prevent undermining
Site drainage should be designed to readily remove surface water and to prevent ponding of water on
subgrade areas during construction and also adjacent to foundations and perimeter slabs once construction
is completed.
If any soil conditions encountered during construction are found to differ from those noted above, Tectonic
should be notified immediately and an inspection carried out to determine if changes to footing design are
required.
Your attention is drawn to the attached document, Limitations.
Please contact the undersigned if you have any questions regarding this letter.
Yours faithfully,
TECTONIC GEOTECHNICAL PTY LTD
Michael Cocks BEng (Civil/Geotechnical) NER RPEQ 27540
Senior Geotechnical Engineer
Attachments: Figure 1
Borehole & DCP Reports & Explanatory Notes
Limitations
3/3
Page 4
Tectonic Geotechnical Pty Ltd
PO Box 899
Buderim Qld 4556
Ph: 07 5478 9016
PROJECT:
PROPOSED RESIDENCE
21 MAHER TERRACE,
SUNSHINE BEACH
BH1
TITLE:
BH4 SITE PLAN
CLIENT:
Subject Site DCP4 BH2
LIBBY & GREG BAYNTON
DRAWN: DATE:
DCP3 MCC 13/01/2023
BH3
CHECKED: DATE:
RKG 13/01/2023
SCALE:
AS SHOWN (APPROX.)
LEGEND:
Approx. 2021 Borehole
Locations
Approx. 2021 Standalone
DCP Test
Approx. 2023 Borehole
Locations
Approx. 2023 Standalone
Notes: DCP Test
Base plan adopted from Nearmap imagery dated 24 November 2022
PROJECT NO.: FIGURE: REV:
21236-002 1 0
Page 5
Borehole No.
BH1
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: Libby & Greg Baynton Commenced: 22/6/2021
Project Name: Proposed Residence Completed: 22/6/2021
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: MCC
Hole Position: 511078.0 m E 7080008.0 m N MGA2020 Zone 56 Checked By: DJP
Drill Model and Mounting: 4WD Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Contract Drilling
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
Clayey SAND (FILL), fine to coarse grained, grey,
medium plasticity clay fines
L
HA
DS CI-CH Sandy CLAY, medium to high plasticity, pale Augered to 0.9m
VSt
0.8-1.0m brown to brown and grey, fine to medium grained
1 M
SC-SM sand MD
DS (RESIDUAL)
1.1-1.4m >20
Silty Clayey SAND, fine to coarse grained, yellow
brown, low plasticity clay fines, trace of fine to Refusal
medium sized gravel
SC
with some weak cementation
Clayey SAND, fine to medium grained, pale
yellow brown and minor red grey, low plasticity
clay fines
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 16/7/2021 08:59 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
Augered to 2.0m
AD/T
2 (EXTREMELY WEATHERED MATERIAL)
SC
Clayey SAND, fine to coarse grained, pale yellow >20
brown and pale grey, low plasticity clay fines, Refusal
Not Encountered
tending to very low strength sandstone
VD
Augered to 3.0m
3 D >20
Refusal
4
SANDSTONE, distinctly weathered, fine to
AD/V
coarse grained, yellow brown and pale grey, very
low strength
Augered to 4.5m
>20
Refusal
5
becoming very low to low strength
Hole Terminated at 5.40 m
Auger refusal on inferred low strength sandstone
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 6
Borehole No.
BH2
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: Libby & Greg Baynton Commenced: 22/6/2021
Project Name: Proposed Residence Completed: 22/6/2021
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: MCC
Hole Position: 511089.0 m E 7079989.0 m N MGA2020 Zone 56 Checked By: DJP
Drill Model and Mounting: Hand Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Contract Drilling
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
Clayey SAND (FILL), fine to coarse grained, dark
grey, trace of rootlets, trace of fine to medium
sized gravel L
becoming dark brown
150
Sandy CLAY (FILL) medium to high plasticity,
brown, grey and pale grey, fine to medium St
Not Encountered
grained sand
1
SC Clayey SAND, fine to medium grained, dark grey, MD 250
trace of organics
DS M
HA
CI-CH (Remnant TOPSOIL)
1.2-1.5m
Sandy CLAY, medium to high plasticity, red
brown, brown, yellow brown and pale grey, fine to VSt
medium grained sand
(RESIDUAL)
250
SC Clayey SAND, fine to medium grained, red
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 16/7/2021 08:59 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
brown, yellow brown and pale grey, medium Augered to 2.0m
2 MD
plasticity clay fines
250
CH Sandy CLAY, high plasticity, red brown, yellow
brown and pale grey, fine to medium grained VSt
sand
Hole Terminated at 2.50 m
Practical hand auger refusal
3
4
>20
Refusal
5
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 7
Borehole No.
BH3
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: GV Emanuel Constructions Commenced: 9/1/2023
Project Name: Proposed Residence Completed: 9/1/2023
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: LM
Hole Position: 511077.0 m E 7079976.0 m N MGA2020 Zone 56 Checked By: MCC
Drill Model and Mounting: 4WD Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Tectonic
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
CI Silty Sandy CLAY, medium plasticity, pale grey,
red and brown, fine to coarse grained sand St
(RESIDUAL)
300
310
becoming brown to pale grey, with fine grained
Not Encountered
1 sand VSt
330
AD/T
M
380
450
CI Sandy CLAY, medium plasticity, pale grey and
red brown, fine to coarse grained sand
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 13/1/2023 10:57 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
2 (EXTREMELY WEATHERED MATERIAL) 450
20/90mm
H Refusal
Augered to 2.6m
Hole Terminated at 2.60 m
Target depth
20/90mm
3 Refusal
4
5
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 8
Borehole No.
BH4
Page 1 of 1
Engineering Log - Borehole Project No.: 21236
Client: GV Emanuel Constructions Commenced: 9/1/2023
Project Name: Proposed Residence Completed: 9/1/2023
Hole Location: 21 Maher Terrace, Sunshine Beach Logged By: LM
Hole Position: 511075.0 m E 7079983.0 m N MGA2020 Zone 56 Checked By: MCC
Drill Model and Mounting: 4WD Auger Inclination: -90° RL Surface: No survey
Hole Diameter: 100 mm Bearing: 360° Datum: AHD Operator: Tectonic
Drilling Information Material Description and Observations
Relative Density
Classification
Pocket DCP TEST
Penetration
Consistency
Graphic Log
Samples Material Description (AS 1289.6.3.2-1997)
Penetrometer
Recovery
Condition
Tests soil type: plasticity or particle characteristics,
Moisture
UCS Blows per 100 mm
Symbol
Method
Remarks secondary and minor components, colour
Water
RL Depth (kPa)
(m) (m) 0 5 10 15 20 25
100
200
300
400
500
Silty Sandy CLAY (FILL), medium plasticity, red
to pale grey brown, fine grained sand St 350
CI Silty Sandy CLAY, medium plasticity, pale grey to
red brown, fine to coarse grained sand 320
(RESIDUAL)
350
1 VSt
Not Encountered
20/80mm Refusal, Augered to 1.6m
AD/T
M 500
CI Silty Sandy CLAY, medium plasticity, pale grey 20/70mm
and red brown, fine to coarse grained sand Refusal
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 21236.GPJ <<DrawingFile>> 13/1/2023 10:57 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
2 (EXTREMELY WEATHERED MATERIAL)
H
tending to very low strength sandstone
Augered to 2.7m
3 20/100mm
Refusal
Hole Terminated at 3.20 m
Target depth
4
5
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
AD/T-Auger Drilling TC Bit VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
AD/V-Auger Drilling V Bit E - Easy DS - Disturbed Sample M - Moist S - Soft
RT - Rotary Tri-cone Bit Inflow BDS - Bulk Disturbed Sample W - Wet F - Firm
RD - Rotary Drilling F - Firm SPT - Standard Penetration Test VSt - Very Stiff
Partial Loss
NMLC -Rock Core H - Hard H - Hard
VH - Very hard Complete Loss
HA - Hand Auger Plastic Limit VL - Very Loose
Graphic Log/Core Loss L - Loose
Classification Symbols and < PL MD - Medium Dense
Core recovered (hatching Soil Descriptions
indicates material) = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Core loss Fr - Friable
Classification System
Page 9
CLIENT : Libby & Greg Baynton SHEET : 1 OF 1
CONTRACTOR :
PROJECT : Proposed Residence
LOCATION : 21 Maher Terrace, Sunshine Beach
PROJECT No. : 21236
TEST: DCP3
LOGGED: MCC 22/6/2021 CHECKED: DJP
28/6/2021
EASTING: 510087.0 m NORTHING: 7079979.0 m
Depth (m)
MGA2020 Zone 56
Blows per 100 mm (AS 1289.6.3.2-1997)
0 5 10 15 20 25
1
2
TECTONIC 3.00.2 LIB.GLB Log IS DCP 3 PER PAGE 21236.GPJ <<DrawingFile>> 16/7/2021 09:01 10.00.01.07 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
3
4
5
>15
Comments
Page 10
CLIENT : GV Emanuel Constructions SHEET : 1 OF 1
CONTRACTOR :
PROJECT : Proposed Residence
LOCATION : 21 Maher Terrace, Sunshine Beach
PROJECT No. : 21236
TEST: DCP4
LOGGED: LM 9/1/2023 CHECKED: DJP
13/1/2023
Depth (m)
Blows per 100 mm (AS 1289.6.3.2-1997)
0 5 10 15 20 25
20/90mm
Refusal
1
2
TECTONIC 3.00.2 LIB.GLB Log IS DCP 3 PER PAGE 21236.GPJ <<DrawingFile>> 13/1/2023 10:58 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
3
4
5
Comments
Page 11
TERMS USED ON LOGS
DRILLING/EXCAVATION METHOD
AD* Auger Drilling RA Rotary Air BH Tractor Mounted Backhoe
ADH Hollow Auger RD Rotary Blade or Drag bit EX Tracked Hydraulic Excavator
HA Hand Auger RT Rotary Tri-cone bit HMLC Core – 63mm
*T TC-Bit HQ Core – 63mm
*V V-Bit NMLC Core – 47mm
NQ Core – 52mm
R Ripper
RH Rock Hammer
WATER
GROUNDWATER NOT The observation of groundwater, whether present or not, was not possible due to drilling water,
OBSERVED surface seepage or cave in of the borehole/test pit.
GROUNDWATER NOT The borehole/test pit was dry soon after excavation. However, groundwater could be present in
ENCOUNTERED less permeable strata. Inflow may have been observed had the borehole/test pit been left open
for a longer period.
SAMPLING AND TESTING
SPT Standard Penetration Test to AS1289.6.3.1-2004
5,4,10 N=14 5,4,10 = Blows per 150mm. N = Blows per 300mm penetration following 150mm seating
30/65mm Where practical refusal occurs, the blows and penetration for that interval are reported
RW Penetration occurred under the rod weight only
HW Penetration occurred under the hammer and rod weight only
HB Hammer double bouncing on anvil
DS Disturbed sample
BDS Bulk disturbed sample
SV Field shear vane test expressed as uncorrected shear strength (sv = peak value, sr = residual value)
PP Pocket penetrometer test expressed as instrument reading in kPa
U50 Thin walled tube sample - number indicates nominal sample diameter in millimetres
DCP Dynamic cone penetration test
CPT Electronic cone penetration test
CPTu Electronic cone penetration test with pore pressure (u) measurement
Rev1
February 2021
Page 12
METHOD OF SOIL DESCRIPTION
USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Soil is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
Particle Size Plasticity Properties
Major Sub Division Particle Size
Division
BOULDERS > 200 mm
COBBLES 63 to 200 mm
Coarse 19 to 63 mm
GRAVEL Medium 6.7 to 19 mm
Fine 2.36 to 6.7 mm
Coarse 0.6 to 2.36 mm
SAND Medium 0.21 to 0.6 mm
Fine 0.075 to 0.21
SILT 0.002 to 0.075
CLAY < 0.002 mm
NOTE: The U line is an approximate upper bound for most materials.
Data which plot above the U line may represent unusual/problem soil
behavior, or unreliable data and should be considered carefully.
MOISTURE CONDITION AS1726 - 2017
Symbol Term Description
D Dry Sands and gravels are free flowing. Clays & Silts may be brittle or friable and powdery.
M Moist Soils are darker than in the dry condition & may feel cool. Sands and gravels tend to cohere.
W Wet Soils exude free water. Sands and gravels tend to cohere.
CONSISTENCY AND DENSITY AS1726 - 2017
Symbol Term Undrained Shear Symbol Term Density Index % SPT “N” #
Strength
VS Very Soft 0 to 12 kPa VL Very Loose Less than 15 0 to 4
S Soft 12 to 25 kPa L Loose 15 to 35 4 to 10
F Firm 25 to 50 kPa MD Medium Dense 35 to 65 10 to 30
St Stiff 50 to 100 kPa D Dense 65 to 85 30 to 50
VSt Very Stiff 100 to 200 kPa VD Very Dense Above 85 Above 50
H Hard Above 200 kPa
In the absence of test results, consistency and density may be assessed from correlations with the observed behaviour of
the material.
# SPT correlations are not stated in AS1726 – 2017, and may be subject to corrections for overburden pressure and
equipment type.
Rev1
October 2017
Page 13
METHOD OF ROCK DESCRIPTION USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Rock is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
STRENGTH
Point Load
Symbol Term Index, Is(50) Field Guide
(MPa)
VL Very 0.03 to 0.1 Material crumbles under firm blows with sharp end of pick; can be peeled
Low with knife; too hard to cut a triaxial sample by hand. Pieces up to 30 mm
can be broken by finger pressure.
L Low 0.1 to 0.3 Easily scored with a knife; indentations 1 mm to 3 mm show in the specimen
with firm blows of pick point; has dull sound under hammer. A piece of core
150 mm long by 50 mm diameter may be broken by hand. Sharp edges of core
may be friable and break during handling.
M Medium 0.3 to 1 Readily scored with a knife; a piece of core 150 mm long by 50 mm diameter
can be broken by hand with difficulty.
H High 1 to 3 A piece of core 150 mm long by 50 mm diameter cannot be broken by hand but
can be broken with pick with a single firm blow; rock rings under hammer.
VH Very 3 to 10 Hand specimen breaks with pick after more than one blow; rock rings under
High hammer.
EH Extremely >10 Specimen requires many blows with geological pick to break through intact
High material; rock rings under hammer.
Relationship between Is(50) and UCS (unconfined compressive strength) will vary with rock type and strength, and
should be determined on a site-specific basis. UCS is typically 10 to 30 x Is(50), but can be as low as 5.
ROCK MATERIAL WEATHERING
Symbol Term Field Guide
Soil developed on extremely weathered rock; the mass structure and
Residual
RS substance fabric are no longer evident; there is a large change in volume
Soil but the soil has not been significantly transported.
Extremely Rock is weathered to such an extent that it has soil properties - i.e. it either
EW
Weathered disintegrates or can be remoulded, in water.
Whole of rock is discoloured, usually by iron staining or bleaching to the
extent that the colour of the original rock is not recognizable. Rock strength
Highly
HW is significantly changed by weathering. Porosity may be increased by
Weathered
leaching, or may be decreased due to deposition of weathering products in
Distinctly
DW pores.
Weathered
Whole of rock is discoloured, usually by iron staining or bleaching to the
Moderately extent that the colour of the original rock is not recognizable; but shows little
MW
Weathered or no change of strength from fresh rock.
Slightly Rock is slightly discoloured but shows little or no change of strength relative
SW
Weathered to fresh rock.
FR Fresh Rock shows no sign of decomposition or staining.
ABBREVIATIONS FOR DEFECT TYPES AND DESCRIPTIONS
Defect Type Coating or Infilling Roughness
CS/CZ Crushed seam/zone (Fault) Ca Calcite Po Polished
DB Drilling break Clay Clay Sm Smooth
EW Extremely weathered seam Cn Clean Sl Slickensided
HB Handling break Co Coating ( > 1mm) Ro Rough
IS/IZ Infilled seam/zone Fe Iron oxide VRo Very rough
Op Open
J Joint
Qz Quartz
Pt Parting St Stain Planarity
SS/SZ Sheared seam/zone (Fault) Vn Veneer (<1mm) Cu Curved
Vn Vein X Carbonaceous Dis Discontinuous
Ir Irregular
Pl Planar
St Stepped
Un Undulating
Rev4
February 2021
Page 14
LIMITATIONS This document has been prepared for the purpose outlined in Tectonic’s proposal and no responsibility is accepted for the use of this document, in whole or in part, for any other purpose. The scope of Tectonic’s Services are as described in Tectonic’s proposal, and are subject to restrictions and limitations. Tectonic did not perform a complete assessment of all possible conditions or circumstances that may exist at the site referenced in the report. If a service is not expressly indicated, do not assume it has been provided. If a matter is not addressed, do not assume that any determination has been made by Tectonic in regards to it. Conditions may exist which were undetectable given that economic and time constraints limit the practical extent of geotechnical investigation. Variations in conditions may occur between investigation locations, and there may be special conditions pertaining to the site which have not been revealed by the investigation and which have not therefore been taken into account in the document. Where variations exist on site, additional studies and actions may be required. Tectonic’s opinions are based upon information that existed at the time that the work was performed. The passage of time, man-made or natural events, may alter the site conditions. It is understood that the Services undertaken allowed Tectonic to form an opinion of the actual conditions of the site at the time the site was visited and cannot be used to assess the effect of any subsequent changes in the quality of the site, or its surroundings, or any laws or regulations. Any assessments made in the preparation of this document are based on the conditions indicated from published sources and the findings of the investigation described. Actual subsurface conditions may differ from those indicated in the document (e.g. between boreholes or test pits). No warranty is included, either express or implied, that the actual conditions will conform exactly to the assessments contained in this document. Where data supplied by the client or other external sources, including previous site investigation data, have been used, it has been assumed that the information is correct unless otherwise stated. No responsibility is accepted by Tectonic for incomplete or inaccurate data supplied by others. This document is provided for the sole use by the Client and its professional advisers. No responsibility whatsoever for the contents of this document will be accepted to any person other than the Client. Any use which a third party makes of this document, or any reliance on or decisions to be made based on it, is the responsibility of such third parties. Tectonic accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this document. Rev 1 (March 2016)
Used in these records
20220109 - 21236-002-Rev0 Maher Tce.pdfRelated documentApplication case desk ↗
20220109 - 21 Maher Tce, Sunshine Beach - Construction of Detached Dwelling and Swimming Pool - 21236-002-Rev0 Maher Tce.pdfRelated documentApplication case desk ↗
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