14.330 Soil Classification Faculty Server Contact（14.330土壤分类教师服务器联系）.pdf

14.330 SOIL MECHANICS Soil Classification SOIL CLASSIFICATION BASICS Commonly based on grain size and soil consistency. Several classification systems exist: 1. Unified Soil Classification System (USCS) (ASTM D2487-11). 2. American Association of State Highway and Transportation Officials (AASHTO) (ASTM D3282-09). 3. U.S. Department of Agriculture (USDA). 4. Burmister Soil Identification System. 5. Massachusetts Institute of Technology (MIT). Revised 01/2013 Slide 1 of 40 14.330 SOIL MECHANICS Soil Classification SOIL GRAIN SIZES USCS Grain Size Range (mm) Soil Type Symbol USCS AASHTO USDA MIT Gravel G 76.2 to 4.75 76.2 to 2 2 2 4.75 to Sand S 2 to 0.075 2 to 0.05 2 to 0.06 0.075 0.075 0.05 to 0.06 to Silt M Fines to 0.002 0.002 0.002 0.075 Clay C 0.002 0.002 0.002 Determined by Mechanical Analysis (i.e. Sieve) and Hydrometer Analysis (ASTM D422-63 (2007) Standard Test Method for Particle-Size Analysis of Soils) Revised 01/2013 Slide 2 of 40 14.330 SOIL MECHANICS Soil Classification MECHANICAL SIEVE ANALYSIS (ASTM D442, D1140 AND AASHTO T88)