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Page 1 of ~ TEST RORI NG . AND LOGG I NG METHOns' STANnARn PENETRATION - SPLIT SPOON TEST A 1-1/8" ro, 2" 00 steel sampling tuhe is rlriven into the soil with a 140-pound hamner falling 30". The number of hamner blows requirerl to drive the sampler 1', after an initi al set of ll?', is the standard penetration resistance ("N" val ue ) . The bore ~ole is advanced between sampling intervals with flight auger, hollow stem auger, casing, or hy rotary drilling with drilling fluid. AUGER BORINGS Aug~r borings are drilled by hand or with a power-driven auger. The hand auger method consists of drilling the auger into the soil in increments of approximately 4", then retracti ng the auger and observing the materi al re- covered. This allows almost continuous observation of the soil profile. Two procedures are available in drilling power auger borings: "spinning" and "pulling." In the spinning procedure, the auger is drilled into the ground in incre- ments of 5', or less. The auger is then spun rapidly. Soil "rides Up" the flights of the auger to the ground surface, where samples are taken. In general, this method results in reasonably accurate identification of the soil profile above the ground water table, but it can be very misleading - particularly in sandy and gravelly soils - below the water table. In the pulling procedure, the auger is drilled into the ground and then withdrawn to above the ground surface. The general soil. profile can he observed, and samples of materials adhering to the auger are taken. In general, this method is considered to he a little more accurate than the spinning method in soil above the ground water table, and considerably more accurate than the spinning method in soil below the ground water tahle. THIN-WALLED TURE SAMPLES Relatively undisturbed samples are taken with thin-wallerl tubes. The tube is pushed into the soil and retracted with the soil sample inside the tube. STATlr. CONE TESTS The static cone test consists of measuring the force required to push a steel cone penetrometer into soil. The cone is pusherl at a rate of approximately 1/2" per second. The static cone bearing pressure, qc' ;s the total load rl;v;ded hy the projected enrl area of the cone. Cone diameters available are 1-3/4", 2-1/4", and 3". The apex angle is fiOo. A hand cone penetrometer is often used in conjunction with hanrl auger borings. It has a 300 apex angle and a projected end area of O.~ square inches.