Explanation of Common Terms Used in Soil Descriptions <br />Cohesive Soils <br />ld Id <br />Fi <br />tifi <br />ti <br />Granular Soils <br />e <br />en <br />ca <br />on <br />I 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. I <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 - 8 <br />I <br />0.25 - 0.50 <br />Medium Stiff <br />Firm <br />11 - 30 <br />Medium <br />Dense <br />I <br />Readily indented by thumb but <br />~ penetrated only with great effort. <br />I 9 - 15 <br />0.50 - 1.0 <br />Stiff <br />31 - 50 <br />Dense <br />II Readily indented b thumbnail. I 16 30 <br />1.0 _ 2,0 <br />Very Stiff <br />> 50 <br />Very Dense <br />Indented with difficulty by 31 60 <br />thumbnail. <br />> 2.0 <br />Hard <br />Undroined 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 of or near plastic limit. <br />Wet <br />Visible water on larger grain surfaces. Sand and cohesionless silt exhibit dilotancy. <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 PI Plasticity Field Test <br />Nonplostic 0 - 3 Cannot be rolled into a thread. <br />Low Plasticity 3 - 15 Can be rolled into o thread with some difficulty. <br />~I Medium Plasticity <br />15 - 30 Easily rolled into thread. <br />l\ High Plasticity I <br />> 30 f Easily rolled and rerolled into thread- <br />Term <br />Soil Structure Criteria 1 <br />r Term <br />Soil Cementation Criteria <br />Stratified I <br />Alternating layers at least 1 inch I <br />thick - describe variation. <br />Weak <br />Breaks under light finger <br />pressure. <br />Laminated I <br />Alternating layers at less than <br />1 inch thick - describe variation. <br />Moderate <br />Breaks under hard finger <br />pressure. <br />Fissured <br />Contains shears and partings I <br />along planes of weakness. <br />Strong <br />Will not break with finger <br />pressure, <br />Slickensides <br />Partings appear glossy or striated. I <br />I <br />Blocky I <br />Breaks into lumps - crumbly. <br />Lensed <br />Contains pockets of different soils <br />describe variation. J <br />~ <br />FOUNDATION <br />ENGINEERING R VI <br />FESSIONAALJGEOTECHNC L SERVICES <br />PR CES <br />820 NM CORNELL AV& <br />_ CORVAILS. OR 07330-4517 <br />BUS. (841) 757-7045 PAX (541) 757-7650 <br />COMMON TERMS <br />SOIL DESCRIPTIONS <br />1464 <br />