Dutch Friction-Cone Penetrometer Exploration of Research Area at Field 5, Eglin AFB, Florida.

摘要

This is a report on the results of an investigation of the homogeneity of soil conditions at a research site within Eglin AFB, Florida. Twenty cone soundings, using a static, Dutch friction-cone penetrometer, reached an average depth of 70 ft, varying from 62 to 102 ft. The field work was accomplished in four working days. The load on the penetrometer was automatically recorded for 11 of these soundings, permitting greater precision in the determination of the ratio of soil friction against the cone friction jacket to the bearing capacity of the cone point. All mechanical equipment appeared to operate in an excellent manner. No evidence was found to indicate significant thicknesses of cohesive soil layers. Friction ratios were unusually uniform over the entire site investigated and fell within the range usually interpreted as indicating clean sand. There was also no evidence of perched water tables. The cone bearing logs for the upper 20 ft of sand, a natural deposit, also indicated that it is uniform in density variation with depth over the research area investigated in detail, and the surrounding area as well. Below 20 ft there is considerable point-to-point variation in sand density. However, on the average the research area and vicinity show a definite uniformity in the way in which density varies with depth. The entire site area is as homogeneous as one can expect to find in natural, coarse-grained deposits of the depth considered herein. (Author)