Explanation of Common Terms Used in Soil Descriptions <br />ld Ide <br />Fi <br />tifi <br />ti <br />Cohesive Sods <br />Granular Soils <br />e <br />n <br />ca <br />on <br />SPT <br />S. (tsf) <br />Term <br />SPT <br />Term <br />Easily penetrated several inches <br />by fist. <br />0 - 1 <br />< 0.125 <br />Very Soft <br />0 - 4 <br />Very Loose <br />Easily penetrated several inches <br />b thumb. <br />2 - 4 <br />0.125-0.25 <br />Soft <br />5 - 10 <br />Loose <br />Can be penetrated several inches <br />by thumb with moderate effort. <br />5 _ g <br />0.25 - 0.50 <br />Medium Stiff <br />(Firm) <br />11 - 30 <br />Medium <br />Dense <br />Readily indented by thumb but <br />penetrated only with great effort. <br />g _ 15 <br />0.50 - 1.0 <br />Stiff <br />31 - 50 <br />Dense <br />Readily indented by thumbnail. <br />16 - 30 <br />1.0 - 2.0 <br />Very Stiff <br />> 50 <br />Very Dense <br />Indented with difficulty by <br />thumbnail. <br />31 - 60 <br />> 2.0 <br />Hord <br />' Undrained shear strength <br />Term <br />Soil Moisture Field Description <br />Dry <br />Absence of moisture. Dusty. Dry to the touch. <br />Damp <br />Soil has moisture. Cohesive soils are below plastic limit and usually moldable. <br />Moist <br />Grains appear darkened. but no visible water. Silt/cloy will clump. Sand will bulk. Soils <br />ore often at or near plastic limit. <br />Wet <br />Visible water on larger groin surfaces. Sand and cohesionless silt exhibit dilatancy. <br />Cohesive silt/cloy con be readily remolded. Soil leaves wetness on the hand when <br />squeezed. "Wet" indicates that the soil is wetter than the optimum moisture content and <br />above the plastic limit- <br />Term <br />PI <br />Plasticity Field Test <br />Nonplostic <br />0 - 3 <br />Cannot be rolled into a thread. <br />Low Plasticity <br />3 - 15 <br />Con be rolled into o thread with some difficulty. <br />Medium Plasticity <br />15 - 30 <br />Easily rolled into thread. <br />High Plasticity <br />> 30 <br />Easily rolled and rerolled into thread. <br />Term <br />Soil Structure Criteria <br />Term <br />Soil Cementation Criteria <br />Stratified <br />Alternating layers at least 1 inch <br />thick - describe variation. <br />Weak <br />Breaks under light finger <br />pressure. <br />Laminated <br />Alternating layers at less than <br />1 inch thick - describe variation. <br />Moderate <br />Breoks under hard finger <br />pressure. <br />Fissured <br />Contains shears and partings <br />along planes of weakness. <br />strong <br />Will not break with finger <br />pressure. <br />Slickensides <br />Partings appear glossy or striated. <br />Blocky <br />Breaks into lumps - crumbly. <br />Lensed <br />Contains pockets of different soils <br />- describe variation. <br />I,IIIIII' FOUNDATION ENGINEERING INC. <br />> Wlllll PROFESSIONAL GEOTECHNICAL SERVICES <br />828 NR CORNEL. AVE. <br />CORVALIS. OR 97330-4517 <br />BUS. (541) 757-7645 RAX (541) 757-7650 <br />COMMON TERMS <br />SOIL DESCRIPTIONS <br />1464 <br />