The effect of temperature on shear characteristics of interface between sand and concrete considering the fine-grained soil content

Abstract In the process of heat conduction between thermo-active ground structures and the ground, the change of the temperature field will lead to the change of the soil stress field and the change of mechanical properties of soil and soil-structure interface. Based on the quadruple shear strain-co...
Ausführliche Beschreibung

Abstract In the process of heat conduction between thermo-active ground structures and the ground, the change of the temperature field will lead to the change of the soil stress field and the change of mechanical properties of soil and soil-structure interface. Based on the quadruple shear strain-controlled direct shear apparatus, a temperature-controlled system was added and converted into a temperature-controlled direct shear apparatus. A series of temperature-controlled interface direct shear tests were carried out between sand and concrete with different contents of fine-grained soil to investigate the effect of the fine-grained soil content and temperature on the interface shear strength parameters. Based on the shear strength theory of unsaturated soil, the interface friction mechanism was summarized, and the micro mechanism of temperature effect of the interface shear characteristics was analyzed. It is found that the temperature has little effect on the type of the interface shear stress versus shear displacement curve (τ-l curve), but has a slight effect on the peak point. When the content of fine-grained soil β≤11%, the interface shear strength index first decreases and then increases with the increase of temperature, and the minimum value appears at the temperature of 40°C (T=40°C). The interface shear strength indexes all increase with the increase of temperature when β >11%. With the increase of the fine-grained soil content, the interface internal friction angle is negatively correlated, and the interface cohesion force is positively correlated. Ausführliche Beschreibung