Is soil highly organic, coarse grained, or fine grained? 1a and Fig. UNIFIED SOIL CLASSIFICATION . 4 sieve size are to be in metric units. Sand: 40% Silt: 40% Clay: 20% Solution: Based on the USDA triangle, the soil is Loam. Contents:Unified Soil Classification System1. For classification, a clay is a fine-grained soil, or the fine-grained portion of a soil, with a the Unified Soil Classification System (USCS), which is based on a combination of physical and behavioral properties. 1. Determining the Unified Soil Classification System (USCS) Symbol and Group Name with Modifier using lab data (ASTM D2487) The descriptive information assists with esti-mating engineering properties such as … USDA Soil Classification Example Based on the sieve analysis of a granular backfill soil, the following percentages of aggregate sizes were identified from the gradation chart. Each of the referenced classification systems was 14.330 SOIL MECHANICS Soil Classification Soil Type USCS Symbol Grain Size Range (mm) USCS AASHTO USDA MIT Gravel G 76.2 to 4.75 76.2 to 2 >2 >2 Sand S 4.75 to 0.075 2 to 0.075 2 to 0.05 2 to 0.06 Silt M Fines < 0.075 0.075 to 0.002 0.05 to 0.002 0.06 to 0.002 Clay C < 0.002 < 0.002 < 0.002 Determined by Mechanical Analysis (i.e. It can If the soil has properties which do not distinctly place it into a Illustrated Guide 2. • Classification is the laboratory-based process of grouping soils with similar engineering characteristics into categories. 1. Basis of Unified Soil Classification System. 200 sieve Well graded GW Poorly graded GP Between 5% and 12% pass No. Franklin Hiram King (1848-1911), US father of soil physics. SYSTEM: FIELD METHOD . Note 1: Use of this standard will result in a single classification group symbol and group name except when a soil contains 5 to 12 % fines or when the plot of the liquid limit and plasticity index values falls into the crosshatched area of the plasticity chart. Unified Soil Classification System (USCS)—Generalized Well-Graded (many sizes): Gravels GW Well-graded gravel Sands SW Well-graded sand Poorly-Graded (uniform size) Gravels GP Poorly-graded gravel Sands SP Poorly-graded sand Sands with enough fines to stain a … 200 sieve size) FINE GRAINED SOILS (More thon 50% of material is SMALLER than No. The USCS is based on engineering properties of a soil; it is most appropriate for earthwork construction. The classification and description requirements are easily associated with actual soils, and the system is flexible enough to … A geotechnical engineering soil classification example using the Unified Soil Classification System (USCS). Each letter is described below (with the exception of Pt): The AASHTO system (M 145), which is However, it alone does not provide adequate descriptive terminology and … Coarse grained Soils2. UNIFIED SOIL CLASSIFICATION SYSTEM Name Group Symbols LABORATORY CRITERIA Fines (%) Grading Plasticity Notes coarse grained (more than 50% larger than 63 μm BS or No.200 US sieve size (0.074 mm)) Gravels (more than 50% of coarse fraction of gravel size) Well graded gravels, with little or no fines GW 0-5 C u >4 1