Influence of sand content on the stress-strain behavior of silicon sand mixed bentonite in CRS condition

Constant rate of strain tests have been widely used to investigate the strain-rate effects on behaviors of clayey soils. Due to highly absorbent nature, the bentonite obviously demonstrates creep, swelling, and strain rate effects. This paper focuses on the influence of sand content on the one-dimensional strain rate dependent stress-strain behavior of a Silicon Sand Mixed Bentonite (SMB) based on the CRS test data. To study the strain rate effects and the influence of sand content on the one-dimensional stress-strain behavior, a total of five CRS tests with five different sand contents (50, 60, 70, 80 and 90) were conducted. The stress-strain behavior of the SMB exhibits considerable strain rate effects. Results and related analysis are presented in this paper. The results also show that the stress-strain behavior of the SMB can be significantly affected by the sand content. A specimen with higher sand proportion has higher stiffness but lower creep ability. The ratio of swelling index over compression index, Cr/Cc is compared in CRS tests and Multi-Stage-Loading (MSL) oedometer tests. The ratio is found to vary from 0.14 to 0.21 in CRS, however 0.20 to 0.41 in MSL.