RW Whittle, Cambridge Insitu. This paper was first published in GE’s May 1999 edition.
This paper presents a closed form solution for undrained cavity expansion and contraction. The shear stress/shear strain response is modelled as non-linear elastic/perfectly plastic with a power law describing the reduction of soil stiffness with strain. The constants of the power law are obtained from pressuremeter unload/reload cycles. The solution can be used to generate a pressuremeter curve for comparison with field data and an iterative procedure with one degree of freedom identifies p„.The analysis is applied to a number of self boring pressuremeter tests in Gault clay at a site in Cambridgeshire.