MINIATURE CONE PENETRATION TESTS IN SOFT AND STIFF CLAYS

An electric continuous intrusion miniature cone penetration test system was recently developed for roadway design and construction control of embankments. The system continuously advances a 2 sq cm electric miniature cone penetrometer by uncoiling a stainless steel push rod. Cone penetration testing advances a cylindrical probe into a soil sample and electronically measures the tip and sleeve resistance due to the intrusion. These resistance parameters are used to classify penetrated sediments and to estimate strength and deformation characteristics of soils. Field and laboratory testing programs were conducted on overconsolidated, normally consolidated, and compacted Louisiana clays. The field testing program consisted of cone penetration tests using both 2 and 15 sq cm electric cone penetrometers in conjunction with soil sampling, while laboratory tests included physical properties and strength characteristics of the investigated soils. Analyses of cone penetration tests were conducted to assess the repeatability and reliability, as well as confirming that the electric miniature friction cone (2 sq cm) output complies with the output of the 15 sq cm cone. The test data will provide the means to calibrate the miniature cone with respect to the commonly used cone penetrometers. It will be used to establish correlations between the miniature cone penetration test results and soil parameters determined in the laboratory and utilize them for roadway design and construction control of highway embankments.