Effect of Elastic Strain in the Plastic Zone on Cavity Expansion Pressure in Sand
摘要
Cavity expansion theory has gained large popularity in Geotechnical engineering field over the last few decades due to its wide range of applicability. The methods of solution for cavity expansion problems can be broadly classified into three groups: (i) closed form; (ii) semi-analytical; and (iii) numerical solutions. The elastic strain in the plastically deforming zone of a cavity was generally ignored to simplify the analysis as it is much smaller than the plastic strain. On the contrary, Yu and Houlsby’s closed-form solution showed that the elastic strain in the plastic region can have a significant influence on the cavity expansion response. The present study is an attempt to quantify the influence of elastic strain on the limit pressure of expanding cylindrical and spherical cavities with the variation of in-situ soil state (friction angle, relative density, shear modulus, etc.). A modified cavity expansion solution procedure based on self-similarity technique similar to the Salgado and Randolph’s approach was developed and used for the parametric analysis. The new solution procedure incorporates the non-linear soil response with the variation of soil state as well as the elastic strain in the plastic zone. In general, the incorporation of elastic strain in the analysis was found to result in a lower cavity limit pressure. The variations of limit pressure due to the contribution of elastic strain as a function of friction angle, relative density, and soil stiffness are presented.