Numerical modeling of the strain rate effect on the stress-strain relation for soft rock using a 3-D elastic visco-plastic model

摘要

It is well known that soft rock exhibits time dependent behavior under the condition of loading. Consolidated undrained triaxial tests were conducted on the specimens of soft rock from the Noto Peninsula of Japan. The test results show that soft rock has a notable strain rate effect; the strength of soft rock is affected by its strain rate during loading. In this paper, a 3-D elastic visco-palstic constitutive model (3-D EVP model) is introduced to simulate the time-dependent behavior of soft rock. In this model the concept of "equivalent time" is defined, and the dime-dependency of materials is taken into account. The 3-D EVP model parameters of a soft rock are determined by an isotropic consolidated test and compression test. The simulated results are obtained through a numerical method, and are compared with the test results. Agreement between them is good. This demonstrates that the 3-D EVP model can describe the timedependent stress-strain behavior of soft rock, and is of importance for soft rock research.