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The thermal effects on geomaterials, especially on clayey soils are getting increasing concerns in many geotechnical applications. To study the effects of temperature on the stress-strain behaviour of Hong Kong marine deposits (HKMD), a series of temperature-controlled experiments were carried out. Oedometer and constant-rate-of-strain consolidation tests under temperatures from 10 °C to 60 °C were conducted on both intact and reconstituted HKMD considering different temperatures and stress paths. The effects of temperature history on the compression curves, thermally induced strain, and the characteristics of creep are revealed and discussed. The concept of virgin heating is proposed for interpreting the thermal plastic deformation. With increasing temperature, the creep coefficient is found to decrease while the creep strain rate increases. Consolidated undrained triaxial tests were performed on intact and reconstituted HKMD under different strain rates and temperature conditions. Under constant temperature, the undrained shear strength of HKMD is not significantly influenced by temperature. In triaxial tests subjected to step-changed temperature, the undrained heating causes a significant reduction of effective stress and rise of porewater pressure in HKMD. Finally, microscopic investigations with mercury intrusion porosimeter and scanning electron microscope are presented and discussed in this paper. It is found that the micropores of HKMD are evolutional with temperature. • Temperature and time dependent behaviour of HKMD is investigated. • Compression curves and shear strength are related to temperature conditions. • Thermal elastic visco-plastic correlations are developed from the test results. • Micro-pores are influenced by temperature according to SEM and MIP tests. • The study will be useful for understanding the thermal effects on clayey soils. [ABSTRACT FROM AUTHOR]

This article presents results from a series of K o -consolidated compression and extension triaxial tests on specimens from undisturbed samples of Hong Kong Marine Deposits (HKMD). To investigate the strain-rate effects, a total of seven K o -consolidated triaxial tests were conducted including four compression tests and three extension tests. After K o -consolidation, the triaxial test specimens were sheared at step-changed axial strain rates under three different confining pressures of 50 kPa, 150 kPa, and 400 kPa, respectively. The step-changed strain rates were applied in the following order: +2%/h, +0.2%/h, +20%/h, -2%/h (unloading) and +2%/h (reloading) for the four compression tests and -2%/h, -0.2%/h, -20%/h, +2%/h (unloading) and -2%/h (reloading) for the three extension tests. The results are reported and analyzed in the paper. The results show that the strain rate effects, the stress-strain characteristics, and the effective stress paths of the specimens for tests in a compression state are different from those for tests in an extension stage. One order of magnitude increase in axial strain rate causes an average 8.6% increase in undrained shear strength for compression tests and a 12.1% increase for extension tests. It is also found that the failure mode of the specimens in compression is different from that in extension. The stress-strain behavior of specimens shows strain-softening and a clear shear band in compression tests, but strain-hardening without any clear shear band in extension tests for the same absolute value of axial strain. [ABSTRACT FROM AUTHOR]