Investigation of thermal effects on the strain rate-dependent properties of compacted bentonite is crucial for the long-term safety assessment of deep geological repository for disposal of high-level radioactive waste. In the present work, cylindrical GMZ01 bentonite specimens were compacted with suctioncontrolled by the vapor equilibrium technique. Then, a series of temperature- and suction-controlled stepwise constant rate of strain (CRS) tests was performed and the rate-dependent compressibility behavior of the highly compacted GMZ01 bentonite was investigated. The plastic compressibility parameter l, the elastic compressibility parameter k, the yield stress p0, as well as the viscous parameter a were determined. Results indicate that l, k and a decrease and p0 increases as suction increases. Upon heating, parameters l, a and p0 decrease. It is also found that p0 increases linearly with increasing CRS in a double-logarithm coordinate. Based on the experimental results, a viscosity parameter a(s, T) was fitted to capture the effects of suction s and temperature Ton the relationship between yield stress and strain rate. Then, an elastic-thermo-viscoplastic model for unsaturated soils was developed to describe the thermal effects on the rate-dependent behavior of highly compacted GMZ01 bentonite. Validation showed that the calculated results agreed well to the measured ones. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Extensive experimental studies have demonstrated the time-dependent mechanical behaviors of frozen soil. Nonetheless, limited studies are focusing on the constitutive modeling of the time-dependent stress-strain behaviors of frozen clay soils at different subzero temperatures. The objective of this study is to numerically investigate the time-dependent behavior of frozen clay soils at a temperature range of 0 degrees C to - 15 degrees C. The Drucker-Prager model is adopted along with the Singh-Mitchell creep model to simulate time-dependent uniaxial compression and stress relaxation behaviors of frozen sandy clay soil. The numerical modeling is implemented through the finite element method based on the platform of Abaqus. The constitutive modeling is calibrated by a series of experimental results on laboratory-prepared frozen sandy clay soils, where the strain hardening, the post-peak softening, and stress relaxation behaviors are captured. Our results show that both the rate-dependent model and creep model should be adopted to characterize a comprehensive time-dependent behavior of frozen soils. The rate-dependent stress-strain behaviors heavily rely on the rate- and temperature-dependent hardening functions, where the creep strain provides a very limited contribution. Nevertheless, the creep strain should also be adopted when a long-term analysis or stress relaxation behavior is involved.