Analysis of cone penetration in brittle liquefiable soils

Abstract

The paper presents a comprehensive set of simulations of the cone penetration test with pore pressure measurements (CPTu test) in brittle, potentially liquefiable, soils using advanced numerical techniques. The large displacements and large deformations involved in the cone penetration problem are tackled using the Particle Finite Element Method, especially adapted for the analysis of coupled geotechnical problems (G-PFEM). A non-local regularization technique is adopted to prevent the pathological mesh dependence associated with continuum analysis of softening materials. Brittle soil behaviour is described using the CASM constitutive model. Undrained CPTu tests are simulated for a range of soils with different degree of brittleness. Effects of permeability, partial drainage and cone roughness are also explored. The results of the analyses are assessed in terms of the interpretation and classification procedures usually applied in practice. In addition, advantage is taken of the availability of a full numerical solution to explore aspects of soil response during penetration that are not possible when only global CPTu observations are available. The full set of numerical analyses have been able to capture the essential features of the problem and to provide useful insights into the effects of brittleness on the mechanisms and results of the CPTu test.