Simulation of multiple-step loading triaxial compression test on a mudstone by a new damage model

Abstract

Multiple-step Loading Triaxial Compression Test (ML-TCT) method is a useful tool to evaluate strength parameters from a single specimen. However, because of accumulated damage in the specimen with repeated cycles of axial loading/unloading,the shear strength is prone to be underestimated.Therefore, a Multiple-step Loading Damage (MLD) model was proposed to simulate ML-TCT swith various stress paths. Two series of ML-TCTs were carried out on a sedimentary soft rock of mudstone. The first series was to determine the geotechnical parameters to describe the MLD model, and the second series was to verify the MLD model.The results demonstrated that the proposed MLD model was applicable for simulation of ML-TCTs on the mudstone and correction the results of carrie dout tests. This model allows prediction of peak deviator stress and the relevant excess pore water pressure due to previous plastic deformations in the specimen for various types of rock.