Drop‐cone penetration in situ and on minimally disturbed soil cores

Abstract

SUMMARY: Drop‐cone penetration was measured both in situ and on minimally disturbed cores at a selection of soil matric potentials for four soils. The drop‐cone penetration/water content relation was linear in situ and, if results for very low water contents were excluded, for the cores. The slope of the line for the field data was much greater than for the core data and this raises doubts about the value of other than in situ measurements of soil strength for predicting field behaviour. Vane shear strength is negatively correlated with in situ drop‐cone penetration. The drop‐cone test is a useful strength test for small volumes of soil, but care must be taken in selecting the mass of the cone as this affects the volume of soil which will influence the test results.