Common use of Topsoil Clause in Contracts

Topsoil. A layer of topsoil, averaging 700 mm in thickness and believed to represent the original grade at the site, was encountered directly below the fill materials at both boreholes. The topsoil consists of a mottled ▇▇▇▇▇/black/grey silt and sand, to sand, some silt, with traces of gravel and organics. Two N-values of 4 obtained within the topsoil layer indicate a loose relative density. A grain size test (curve appended) performed on a topsoil sample shows it to contain 2 percent gravel, 87 percent sand and 11 percent fines. Moisture contents of 63 and 110 percent were obtained for recovered samples of the topsoil and indicate a compressible soil. A layer of ▇▇▇▇▇▇▇-▇▇▇▇▇ glacial till, 0.9 to 1.2 m in thickness, was encountered directly the topsoil at both boreholes. The till was found to vary in composition from a gravelly sand, some silt to a gravelly silt and sand, with occasional clayey zones and sandstone cobbles. The till surface was encountered 2.7 m below present grade, at an elevation ranging from el. 15.08 m at BH-02 to el. 15.18 m at BH-01. N-values obtained within the till stratum were found to range from 26 to 49 indicating a compact to dense relative density. N-values in excess of 30 within the local tills are typically attributed to the presence of sandstone cobbles/layers within the till, and/or the proximity of the underlying bedrock. Grain size testing (curves appended) performed on representative samples of the till show it to contain 21 to 36 percent gravel, 34 to 44 percent sand and 20 to 45 percent fines. The natural moisture content of the till samples was found to range from 13 to 16 percent. Sandstone bedrock was encountered directly below the glacial till stratum at the boreholes, at depths ranging from 3.7 to 4.0 m below existing grade. The elevation of the bedrock surface was found to be relatively uniform at the boreholes, ranging from el. 13.96 m at BH-01 to el. 14.17 m at BH-02. Bedrock was proved by core drilling at BH-02 and was inferred, based on split spoon refusal and resistance to auger advancement, at BH-01. The rock core recovered consists predominantly of very weak to weak, medium grained, reddish ▇▇▇▇▇ sandstone. The bedrock is horizontally bedded with extremely close (<20 mm) to close (60 to 200 mm) joints which typically occur along the bedding planes. Recovery and RQD (Rock Quality Designation) values of 100 percent and 54 percent, respectively, indicate fair quality, fractured bedrock.

Topsoil. A layer of topsoil, averaging 700 760 mm in thickness and believed to represent the original grade at the site, was encountered directly below the fill materials at both boreholesBH-04. The topsoil consists of a mottled ▇▇▇▇▇/blackgrey/grey silt and brown silty sand, to sand, some silt, with traces of gravel gravel, wood, and organics. Two An N-values value of 4 5 obtained within in the topsoil layer indicate a loose relative density. A grain size test (curve appended) performed on a the topsoil sample shows it to contain 2 4 percent gravel, 87 76 percent sand and 11 20 percent fines. Moisture contents A moisture content of 63 43 percent was obtained and 110 percent were obtained for recovered samples of the topsoil and indicate indicates a compressible soil. A layer of ▇▇▇▇▇▇▇-▇▇▇▇▇ glacial till, 0.9 0.5 to 1.2 1.5 m in thickness, was encountered directly below the fill or topsoil at both boreholes(BH-04) layers. The till was found to vary in composition from a gravelly sand, some silt silty sand to a gravelly silt and sand, with trace to some gravel, and occasional clayey zones and sandstone cobbles. The till surface was encountered 2.7 3.5 to 4.3 m below present grade, at an . The elevation ranging of the till surface was found to range from a low of el. 15.08 0.91 m at BH-02 BH-03 to a high of el. 15.18 1.56 m at BH-01BH-02. N-values obtained within the till stratum were found to range from 26 30 to 49 indicating a compact to dense relative density. N-values in excess of 30 within the local tills are typically attributed to the presence of sandstone cobbles/layers within the till, and/or the proximity of the underlying bedrock. Grain size testing (curves appended) performed on representative samples of the till show it to contain 21 8 to 36 17 percent gravel, 34 66 to 44 68 percent sand and 20 17 to 45 24 percent fines. The natural moisture content of the till samples was found to range from 13 17 to 16 19 percent. Sandstone bedrock was encountered directly below the glacial till stratum at the boreholes, at depths ranging from 3.7 4.6 to 4.0 5.0 m below existing grade. The elevation of the bedrock surface was found to be relatively uniform at across the boreholessite, ranging from el. 13.96 0.03 m at BH-01 BH-02 to el. 14.17 0.56 m at BH-02BH-01. Bedrock was proved by core drilling at BH-02 BH-01 and BH-04, and was inferred, based on split spoon refusal and and/or resistance to auger advancement, at BH-01BH-02 and BH-03. The rock core recovered consists predominantly of very weak to weak, medium grained, reddish ▇▇▇▇▇ brown sandstone, with occasional seams of hard mudstone. The bedrock is horizontally bedded with extremely close (<20 mm) to close (60 to 200 mm) joints which typically occur along the bedding planes. Recovery Average recovery and RQD (Rock Quality Designation) values of 100 89 percent and 54 11 percent, respectively, indicate fair very poor quality, very severely fractured bedrock.