Numerical Modeling of Cone Penetration Test in Unsaturated Sand inside a Calibration Chamber

Abstract

Cone-penetration resistance in unsaturated soils may differ from that in dry or saturated soils. A finite-element numerical model simulating the cone penetration process in soil inside a calibration chamber is explained. An arbitrary Lagrangian-Eulerian algorithm was used to overcome the mesh distortion caused by large deformation during penetration. Predicted cone-resistance profiles were validated using calibration-chamber test results and empirical data. Unsaturated soil was modeled using two different approaches: incorporating apparent cohesion in standard constitutive relations and implementing an elastoplastic constitutive model for unsaturated soils. Both approaches resulted in cone-resistance profiles that were in fair agreement with the calibration-chamber data. However, the reasonably successful use of simpler constitutive models with fewer material parameters may be an appropriate option for such applications. Investigations into the effect of degree of saturation on the cone resistance revealed the significant influence of interparticle suction on soil resistance, while they also show that neglecting the saturation effect may lead to unreliable evaluation of soil properties.