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31 <br /> Kennedy/Jenks Consultants <br /> it <br /> 2.4 Typical Procedures <br /> 2.4.1 Soil Classification f 1 <br /> Soils are typically logged in conjunction with advancing boreholes and sampling subsurface soils. <br /> Although the guideline focuses on classifying soil samples obtained from boreholes, this particular <br /> procedure also applies to soils and sediments collected using other techniques (e.g., post hole I <br /> digger, scoop, Van Veen sampler, and backhoe). <br /> The USCS categorizes soils into 15 basic groups, each with distinct geologic and engineering <br /> properties. The following steps are required to classify a soil sample: <br /> 1. Observe basic properties and characteristics of the soil. These include grain-size grading and <br /> a <br /> distribution and influence of moisture on fine-grained soil. <br /> 2. Assign the soil a USCS classification and denote it by the standard group name and symbol. <br /> 3. Provide a written description to differentiate between soils in the same group, if necessary. <br /> Many soils have characteristics that are not clearly associated with a specific soil group. These soils !1 <br /> might be near the borderline between groups, based on either grain-size grading and distribution, or <br /> plasticity characteristics. In this case, assigning dual group names and symbols might be <br /> appropriate (e.g., GW/GC or ML/CL). <br /> The three basic soil groups are: <br /> 1. Coarse-Grained Soils — For soils in this group, more than half of the material is larger than 1 <br /> No. 200 sieve (0.074 mm). (l <br /> 2. Fine-Grained Soils — For soils in this group, one half or more of the material is smaller than ul <br /> No. 200 sieve (0.074 mm). <br /> 3. Highly Organic Soils —This group includes soils with high organic content, such as peat. <br /> Note: No. 200 sieve is the smallest size that can be seen with the naked eye. <br /> 2.4.2 Classification of Coarse-Grained Soils I <br /> Coarse-grained soils are classified on the basis of: <br /> U <br /> 1. Grain size and distribution <br /> 2. Quantity of fine-grained material (i.e., silt and clay) <br /> 3. Character of fine-grained material •l <br /> J <br /> �1 <br /> Hydrogeologic Investigation and Groundwater Sampling and Analysis Work Plan SOG 2 <br /> Sutter Home Lodi Winery, Lodi, California Page 2 of 5 <br /> gMj.pbtl InV.0108i0B65005wak 01 1 JI <br />