Throsby Site Classification - suburbanland.act.gov.au · Brisbane • Cairns • Canberra • Central Coast Coffs Harbour • • Darwin • Geelong • Gold ... the slow progress

Douglas Partners Pty Ltd ABN 75 053 980 117

www.douglaspartners.com.au Unit 2, 73 Sheppard Street

Hume ACT 2620 PO Box 1487

Fyshwick ACT 2609 Phone (02) 6260 2788

Fax (02) 6260 1147

Brisbane Cairns Canberra Central Coast Coffs Harbour Darwin Geelong Gold Coast Macarthur Melbourne Newcastle Perth Port Macquarie Sunshine Coast Sydney Townsville Wollongong

Site Classification Summary Report Client Calibre Consulting (ACT) Pty Ltd Project No. 77374.09

Project Site Classification Date 23/01/2017

Address Block 1 Section 56, Throsby Doc No. R.001.Rev0

Classification Procedure Existing Subsurface Conditions: Test Pit 102: Located on the boundary of Blocks 1 & 2 Section 56. Dry to moist topsoil filling to 0.1 m depth then well compacted, dry to moist silty gravelly clay cobbles filling to 0.4 m depth overlying extremely low to very low strength, extremely to highly weathered siltstone/claystone, grading to very low to low strength, highly weathered at 1.0 m depth, then further grading to low to medium strength, highly weathered siltstone/claystone to the limit of investigation depth of 1.8 m. Test Pit 103: Located on the boundary of Blocks 3 & 4 Section 56. Extremely low strength, extremely weathered claystone/siltstone to 1.4 m depth overlying medium to high strength, moderately weathered with quartz gravels limestone to the slow progress depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Bulk Earthworks: Engineered filling was placed over the block under Level 1 control as defined in AS 3798 2007 (Ref 1). Site Classification Based on soil reactivity the site would be classified as Class S* (slightly reactive/filled site) when reference is made to AS2870-2011 (Ref 2). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 2) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011

Introduction These notes are provided to amplify DPs inspection report in regard to the limitations of carrying out inspection work. Not all notes are necessarily relevant to this report. Standards This inspection report has been prepared by qualified personnel to current engineering standards of interpretation and analysis. Copyright and Limits of Use This inspection report is the property of DP and is provided for the exclusive use of the client for the specific project and purpose as described in the report. It should not be used by a third party for any purpose other than to confirm that the construction works addressed in the report have been inspected as described. Use of the inspection report is limited in accordance with the Conditions of Engagement for the commission. DP does not undertake to guarantee the works of the contractors or relieve them of their responsibility to produce a completed product conforming to the design. Reports This inspection report may include advice or opinion that is based on engineering and/or geological interpretation, information provided by the client or the clients agent, and information gained from:

an investigation report for the project (if available to DP);

inspection of the work, exposed ground conditions, excavation spoil and performance of excavating equipment while DP was on site;

investigation and testing that was carried out during the site inspection;

anecdotal information provided by authoritative site personnel; and

DPs experience and knowledge of local

geology. Such information may be limited by the frequency of any inspection or testing that was able to be practically carried out, including possible site or cost constraints imposed by the client/ contractor(s). For these reasons, the reliability of this inspection report is limited by the scope of information on which it relies. Every care is taken with the inspection report as it relates to interpretation of subsurface conditions and any recommendations or suggestions for construction or design. However, DP cannot anticipate or assume responsibility for:

unexpected variations in subsurface conditions that are not evident from the inspection; and

the actions of contractors responding to commercial pressures.

Should these issues occur, then additional advice should be sought from DP and, if required, amendments made. This inspection report must be read in conjunction with any attached information. This inspection report should be kept in its entirety without separation of individual pages or sections. DP cannot be held responsible for interpretations or conclusions from review by others of this inspection report or test data, which are not otherwise supported by an expressed statement, interpretation, outcome or conclusion stated in this inspection report.

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Classification Procedure Existing Subsurface Conditions: Test Pit 102: Located on the boundary of Blocks 1 & 2 Section 56. Dry to moist topsoil filling to 0.1 m depth then well compacted, dry to moist silty gravelly clay cobbles filling to 0.4 m depth overlying extremely low to very low strength, extremely to highly weathered siltstone/claystone, grading to very low to low strength, highly weathered at 1.0 m depth, then further grading to low to medium strength, highly weathered siltstone/claystone to the limit of investigation depth of 1.8 m. Test Pit 103: Located on the boundary of Blocks 3 & 4 Section 56. Extremely low strength, extremely weathered claystone/siltstone to 1.4 m depth overlying medium to high strength, moderately weathered with quartz gravels limestone to the slow progress depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Bulk Earthworks: Engineered filling was placed over the block under Level 1 control as defined in AS 3798 2007 (Ref 1). Site Classification Based on soil reactivity the site would be classified as Class S* (slightly reactive/filled site) when reference is made to AS2870-2011 (Ref 2). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 2) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 102: Located on the boundary of Blocks 1 & 2 Section 56. Dry to moist topsoil filling to 0.1 m depth then well compacted, dry to moist silty gravelly clay cobbles filling to 0.4 m depth overlying extremely low to very low strength, extremely to highly weathered siltstone/claystone, grading to very low to low strength, highly weathered at 1.0 m depth, then further grading to low to medium strength, highly weathered siltstone/claystone to the limit of investigation depth of 1.8 m. Test Pit 103: Located on the boundary of Blocks 3 & 4 Section 56. Extremely low strength, extremely weathered claystone/siltstone to 1.4 m depth overlying medium to high strength, moderately weathered with quartz gravels limestone to the slow progress depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 103: Located on the boundary of Blocks 3 & 4 Section 56. Extremely low strength, extremely weathered claystone/siltstone to 1.4 m depth overlying medium to high strength, moderately weathered with quartz gravels limestone to the slow progress depth of 1.6 m. Test Pit 104: Located on the boundary of Blocks 5 & 6 Section 56. Dry to moist topsoil filling to 0.2 m depth, stiff to very stiff, moist silty clay to 0.4 m depth, then extremely low strength, extremely weathered siltstone/claystone to 1.3 m overlying medium to high strength, moderately to highly weathered limestone with some quartz gravels to the slow progress depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 103: Located on the boundary of Blocks 3 & 4 Section 56. Extremely low strength, extremely weathered claystone/siltstone to 1.4 m depth overlying medium to high strength, moderately weathered with quartz gravels limestone to the slow progress depth of 1.6 m. Test Pit 104: Located on the boundary of Blocks 5 & 6 Section 56. Dry to moist topsoil filling to 0.2 m depth, stiff to very stiff, moist silty clay to 0.4 m depth, then extremely low strength, extremely weathered siltstone/claystone to 1.3 m overlying medium to high strength, moderately to highly weathered limestone with some quartz gravels to the slow progress depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 104: Located on the boundary of Blocks 5 & 6 Section 56. Dry to moist topsoil filling to 0.2 m depth, stiff to very stiff, moist silty clay to 0.4 m depth, then extremely low strength, extremely weathered siltstone/claystone to 1.3 m overlying medium to high strength, moderately to highly weathered limestone with some quartz gravels to the slow progress depth of 1.6 m. Test Pit 105: Located on the boundary of Blocks 7 & 8 Section 56. Dry to moist topsoil filling to 0.2 m depth, well compacted, dry to moist silty gravelly clay with cobbles filling to 0.6 m depth, very stiff, dry to moist sandy silt to 0.7 m depth, then stiff, moist, sandy clay to 1.3 m depth overlying extremely low strength, extremely weathered siltstone/claystone to the limit of investigation depth of 1.8 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Bulk Earthworks: Engineered filling was placed over the block under Level 1 control as defined in AS 3798 2007 (Ref 1). Site Classification Based on soil reactivity the site would be classified as Class S* (slightly reactive/filled site) when reference is made to AS2870-2011 (Ref 2). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 2) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 104: Located on the boundary of Blocks 5 & 6 Section 56. Dry to moist topsoil filling to 0.2 m depth, stiff to very stiff, moist silty clay to 0.4 m depth, then extremely low strength, extremely weathered siltstone/claystone to 1.3 m overlying medium to high strength, moderately to highly weathered limestone with some quartz gravels to the slow progress depth of 1.6 m. Test Pit 105: Located on the boundary of Blocks 7 & 8 Section 56. Dry to moist topsoil filling to 0.2 m depth, well compacted, dry to moist silty gravelly clay with cobbles filling to 0.6 m depth, very stiff, dry to moist sandy silt to 0.7 m depth, then stiff, moist, sandy clay to 1.3 m depth overlying extremely low strength, extremely weathered siltstone/claystone to the limit of investigation depth of 1.8 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Bulk Earthworks: Engineered filling was placed over the block under Level 1 control as defined in AS 3798 2007 (Ref 1). Site Classification Based on worst case soil reactivity, the site would be classified as Class M* (moderately reactive/filled site) when reference is made to AS2870-2011 (Ref 2). Parts of the site would be equivalent to Class S conditions. It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 2) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 105: Located on the boundary of Blocks 7 & 8 Section 56. Dry to moist topsoil filling to 0.2 m depth, well compacted, dry to moist silty gravelly clay with cobbles filling to 0.6 m depth, very stiff, dry to moist sandy silt to 0.7 m depth, then stiff, moist, sandy clay to 1.3 m depth overlying extremely low strength, extremely weathered siltstone/claystone to the limit of investigation depth of 1.8 m. Test Pit 106: Located on the boundary of Blocks 9 & 10 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with some limestone cobbles, grading to very low to low strength, highly weathered from 1.0 m to the limit of investigation depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Bulk Earthworks: Engineered filling was placed over the block under Level 1 control as defined in AS 3798 2007 (Ref 1). Site Classification Based on worst case soil reactivity, the site would be classified as Class M* (moderately reactive/filled site) when reference is made to AS2870-2011 (Ref 2). Parts of the site would be equivalent to Class S conditions. It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 2) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 105: Located on the boundary of Blocks 7 & 8 Section 56. Dry to moist topsoil filling to 0.2 m depth, well compacted, dry to moist silty gravelly clay with cobbles filling to 0.6 m depth, very stiff, dry to moist sandy silt to 0.7 m depth, then stiff, moist, sandy clay to 1.3 m depth overlying extremely low strength, extremely weathered siltstone/claystone to the limit of investigation depth of 1.8 m. Test Pit 106: Located on the boundary of Blocks 9 & 10 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with some limestone cobbles, grading to very low to low strength, highly weathered from 1.0 m to the limit of investigation depth of 1.6 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Classification Procedure Existing Subsurface Conditions: Test Pit 106: Located on the boundary of Blocks 9 & 10 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with some limestone cobbles, grading to very low to low strength, highly weathered from 1.0 m to the limit of investigation depth of 1.6 m. Test Pit 107: Located on the boundary of Blocks 11 & 12 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with ironstone modules and some limestone boulders to the limit of investigation depth of 1.8 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Fax (02) 6260 1147





Classification Procedure Existing Subsurface Conditions: Test Pit 106: Located on the boundary of Blocks 9 & 10 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with some limestone cobbles, grading to very low to low strength, highly weathered from 1.0 m to the limit of investigation depth of 1.6 m. Test Pit 107: Located on the boundary of Blocks 11 & 12 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with ironstone modules and some limestone boulders to the limit of investigation depth of 1.8 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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Classification Procedure Existing Subsurface Conditions: Test Pit 107: Located on the boundary of Blocks 11 & 12 Section 56. Dry to moist topsoil filling to 0.2 m depth overlying extremely low strength, extremely weathered siltstone/claystone with ironstone modules and some limestone boulders. Some soil like properties were also apparent to the limit of investigation depth of 1.8 m. Test Pit 108: Located on the boundary of Block 13 Section 56. Dry to moist topsoil filling to 0.2 m depth then hard, dry to moist silty clay to 0.4 m depth overlying extremely low to low strength, extremely weathered siltstone/claystone, grading to very low to low strength, highly weathered from 1.2 m and grading to low to medium strength, highly to moderately weathered from 1.5 m to the limit of investigation depth of 1.8 m. No free groundwater was observed during excavation of the test pits. However the pits were backfilled immediately following excavation precluding longer term monitoring of groundwater levels. Groundwater conditions rarely remain constant and can change seasonally due to variations in rainfall, temperature and soil permeability. For these reasons, it is noted that the moisture condition of the site soils may vary considerably from the time of the investigation compared to at the time of construction. Site Classification Based on soil reactivity the site would be classified as Class S (slightly reactive) when reference is made to AS2870-2011 (Ref 1). It must be noted that the residual soil/extremely weathered bedrock is likely to contain limestone cobbles/boulders which would pose some difficulties with respect to excavation, reuse of material and potential stiffness variations in the foundation soils. Whilst considered not to be in sufficient quantities to warrant a P classification, the potential for adverse effects must be considered by potential purchases and/or builders. Should the subsurface profile change by excavation or filling, reassessment of the site classification must be undertaken with the possibility of a Class P site. Footing Systems Reference must be made to AS2870-2011 (Ref 1) which indicates footing systems that are appropriate for each site classification and detailing requirements should limestone boulders be present in footing excavations. All footings must found within a uniform bearing stratum of suitable strength/material, below the zone of influence of any service trenches, backfill zones, retaining walls or underground structures. Masonry walls should be articulated in accordance with current best practice. Footing systems must be confirmed by a structural engineer taking into consideration any onsite or offsite constraints.

September 2011











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