Effect of temperature on the residual shear strength of fine grained soil

Abstract The impact of low-range temperature variation on the residual shear strength parameters has been investigated. For this purpose, a standard ring shear apparatus has been subjected to low-cost modifications and equipped with thermoelectric temperature control system constructed in-house. This allowed to conduct a series of tests for clay samples at temperatures of 5°C and 20°C, which is a typical range of variation for thermo-active structures during heat extraction. In order to distinguish the impact of temperature from the natural variability of the soil samples, additional temperature changes during shearing were performed, after residual strength had been reached. The obtained results revealed an observable impact of the temperature change on the residual shear strength of tested clay; however, the variance has been close to the resolution of the measurement sensor and within the range comparable to the natural variability of fine-grained soils. Therefore, low-range temperature changes can be considered as negligible in regard to the residual shear strength parameters.