Influence of temperature on residual strength of clayey soils

This paper presents the influence of temperature on the residual strength by analyzing shearing tests carried out in a temperature- and velocity-controlled ring shear apparatus. Temperature was applied in steps of cooling and heating ranging between 6 °C and 50 °C at a constant shearing velocity of 0.442 mm/min. Additional tests include the evaluation of the strength at 0.890 mm/min before and after the imposed temperature change. Six basic soil types characterized by different mineralogy, grain size and plasticity, as well as, mixture soils having different proportions of sand and clay, are evaluated and the results are interpreted in terms of their properties. The experimental results reveal that the temperature effect becomes relevant when fine particles and plasticity increase being negligible in the case of the sandy soil. Shear strength reacts immediately to temperature changes and a new residual strength establishes soon. The temperature effect is symmetric. An increase in temperature leads to a decrease in strength, and an equal and opposite trend is observed when temperature decreases. The magnitude of the strength variation is significant in clayey soils. For the case of high plasticity soils, the residual friction angle variation observed during cooling and heating (±50 °C) is around 2°. The strain rate effect evaluated in a smaller number of tests indicated a strain rate strengthening in all the materials tested except for the case of the sandy soil, which also was not reactive to temperature changes. The experiments are calibrated with a velocity, state, and temperature-dependent friction model.

The second author, as associate professor Serra Húnter, gratefully acknowledges the funding from the Departament de Recerca i Universitats de la Generalitat de Catalunya. This publication is part of the R&D&I project RTI2018-097365-B- funded by MCIN/ AEI/10.13039/ 501100011033, “ERDF A way of doing Europe”. The authors also gratefully acknowledge the financial support to CIMNE provided by CERCA/Generalitat de Catalunya program. The first author, as a professor of the Departamento de Ingenieria Civil at the Pontificia Universidad Católica Madre y Maestra (PUCMM), gratefully acknowledges the Centro de Desarrollo Profesoral (CDP) and the Ministerio de Educación Superior, Ciencia y Tecnología (MESCYT) of the Dominican Republic for the financial support for the development of this investigation.

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