Analysis of instrumented sharp cone and pressuremeter tests in stiff sensitive clay

Abstract

The objective of this paper is to compare field test results obtained in a stiff sensitive clay from Quebec using prebored, instrumented sharp cone tests (ISCTs) with those deduced from prebored and self-boring pressuremeter tests (PMTs and SBPMTs, respectively) and vane shear tests (VSTs). Comparisons are also made with triaxial test results. It is shown that undrained shear strengths Sudeduced from PMTs and ISCTs are greatly overestimated with respect to the values inferred from SBPMTs and VSTs. As for the shear modulus G, the opposite is true. These discrepancies are considered to arise from initial disturbance and unloading caused by drilling of pilot holes in the case of PMTs and ISCTs. Interpretation problems may be also related to the existence of very high lateral pressures at rest in the clay deposit.