Numerical Assessment on Shear Moduli at Pre-failure State Taken from Pressuremeter Test

摘要

This paper investigated the deformational characteristics of sandy soils at pre-failure state by using the numerical simulation of pressuremeter tests. Numerical simulations of cavity expansion were performed with a pseudo-elastic soil model, which was developed based on the cross anisotropy concept and the Ramberg-Osgood model for anisotropy and nonlin-earity of soil, respectively. Assumptions of the existing analytical solution on the deformation of sandy soils due to cavity expansion were examined. Model parameters were studied, which describe the nonlinearity and anisotropy of soil deformation. In addition, the effect of finite length of the pressuremeter was numerically estimated, as was the extent of influence of cavity expansion. The existing solution, based on the isotropic and linear elastic assumption, overestimates the tangential shear modulus in the nonlinear strain range. Meanwhile, the tangential modulus taken from the pressuremeter test relatively concurs with the secant modulus of soil. Consequently, the simulation results indicated that the parameters related to the horizontal direction have a dominant effect on the shear modulus.