Opening of Quotes - Laurel Woods Drainage Improvements Proj No. 121-007 - Selge Construction Co., Inc.

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Weaver Consultants Group 3 3 SUBSURFACE CONDITIONS 3.1 Subsurface Conditions Our interpretation of the subsurface conditions is based four test borings. The following discussion is general; for more specific information, refer to the boring logs presented in the boring logs in Appendix A. Surface conditions: The surface conditions along the storm sewer alignment consisted of a variety of conditions including asphaltic paved roads and grass covered areas. At three of the boring locations topsoil depths ranged from 6 to 10 inches. At the location of Boring B -3, road gravel was encountered to a depth of about 8 inches. Subsurface Conditions: In general, below the surficial materials, the subsurface soil profile consisted of granular-type soil to a depth of about 5½ to 11 feet bgs and underlain by silt to a depth of about 9 to 22 feet where sandy lean clay was encountered to the terminal depth of the borings. The upper approximately 11 feet of the granular soil was fill consisting of clayey sand with varying amounts of gravel (SC). Below the fill was naturally occurring fine sand (SP). At a depth of about 13 feet, an approximately 5-foot thick stratum of sandy clay (CL) was encountered. The underlying clay stratum was a poorly-graded sand with a trace of gravel (SP) to the maximum depth explored. The underlying soil layers in the borings are described in more detail below. • Granular soils (SP, SP-SM, SP-SC, SC) – Below the surface materials, granular soils consisting of fine to coarse sand with a trace to little gravel (SP), fine to coarse sand with silt (SP-SM), clayey fine to coarse sand (SC), and fine to coarse sand with clay (SP-SC) were encountered to depths ranging from 5½ to 11½ feet bgs. The relative density of the granular soil was very loose to medium dense with Standard Penetration Test (SPT) N- values ranging from 0 to 14 blows per foot (bpf), generally decreasing with depth. • Silt (ML), and Clayey Silt (CL-ML) – Below the granular soils, silt (ML) was encountered to the terminal depth of the borings or 9 to 22 feet bgs. The silt was typically no t cohesive and contained random amounts of gravel. The relative density of the silt was loose to medium dense with Standard Penetration Test (SPT) N-values ranging from 5 and 13 bpf, typically in the 5 to 8 bpf range. At locations within the silt stratum, thin layers of clayey silt (CL-ML) was encountered. Where encountered, the consistency of the clayey silt was very stiff with a hand penetrometer reading of 2.7, and a moisture content of about 29 percent. • Sandy Clay (CL) – At the deeper boring locations, a stratum of sandy clay with a trace of gravel was encountered to the terminal depth of the borings. The consistency of the clay