Removal of the membrane penetration error from triaxial data

Most triaxial tests are fraught with substantial membrane penetration errors. A simple correction procedure for data obtained from various tests is proposed. Correction formulas for the membrane penetration error have been derived for different types of tests including not perfectly saturated soils. In particular, a correction of the undrained cyclic stress paths is presented in detail. It is demonstrated that the correction for the membrane penetration error is indispensable for a realistic estimation of the cyclic resistance ratio in coarse- and mediumgrained liquefiable soils. A MATHEMATICA code for the correction of laboratory data is given. An analogous MATLAB code is available from the authors. Without the correction many results could lie far on the unsafe side. This is the case especially for the undrained cyclic loading.