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in diameter and forms a long, smooth, thread that is free of cracks, it has high <br /> plasticity and is likely clay. If the thread cracks before it forms an 1/8-inch <br /> diameter thread, and is cracked and crumbles easily when rolled, it has low <br /> plasticity and is likely silt. <br /> 3.4.6 Density <br /> In DPT borings, density is subjective and should be based upon the ease of boring, soil <br /> observations,and soil type. The resistance to pressing of a finger or sampling device into <br /> the sediment can be used to describe the density of sediment. The below adjectives for <br /> granular and cohesive soils should be used in the description. <br /> Granular soils may be assessed and described using the following: <br /> • very loose — easily penetrated with '/2-inch reinforcing rod (or rebar) pushed by <br /> hand; <br /> • loose—easily penetrated with rebar pushed by hand; <br /> • medium dense—penetrated one foot with rebar driven with 5-pound hammer; <br /> • dense—penetrated one foot with rebar driven with 5-pound hammer; and <br /> • very dense—penetrated a few inches with rebar driven with 5-pound hammer. <br /> Cohesive soils may be assessed and described using the following descriptors and tests: <br /> • very soft—easily penetrated several inches with fist; <br /> • soft—easily penetrated several inches by thumb; <br /> • medium stiff—penetrated several inches by thumb; <br /> • stiff—readily indented by thumb; <br /> • very stiff—readily indented by thumbnail; and <br /> • hard—difficult to penetrate with thumbnail. <br /> 3.4.7 Geologic Modifiers <br /> Sedimentological descriptions aid in the geologic classification of a soil material. Only <br /> insert geologic modifiers when certain of their presence. <br /> Geologic Description: Where possible, based on existing Site data, local research, or <br /> geologic understanding of the local region, include a geologic description of the sample. <br /> 10 <br />