Soil Sampling and Drilling Near Fairbanks, Alaska. Equipment and Procedures

Soils explorations were conducted by core drilling methods and by drive sampling methods in thawed and frozen silty soils. Temperatures ranged from 28 to 31.5 deg F in the permafrost and from 20 to 27 deg F in the active layer. The Cyclone churn drill, equipped with a field-fabricated 3 in. diameter pipe sampler, is an effective means for drive sampling in frozen silt soils to a depth in excess of 100 ft. Core drilling and sample recovery has been accomplished by using the Longyear, Acker, and Chicago Pneumatic core drills. A Concore exploration drill has been effective in obtaining core samples from 20 to 30-ft depth in frozen soils. A tripod arrangement for supporting a 350-lb drive hammer operated manually by a rope from the cathead of both Acker and Chicago Pneumatic core drills was also effective for drive sampling frozen silty soils to depths up to 20 ft. Manual driving of a sampler fabricated from thin wall electrical conduit proved to be effective for sampling frozen soils to depths of about 10 ft. Sampler driving by pneumatic hammer and recovery by truck mounted winchline was effective to 10 to 15 ft depth.