Experimental study on adfreezing bond strength of interface between silt and foundation of Qinghai-Tibetan transmission line

The adfreezing bond strength between soils and foundation surface plays an important role in general stability concerns of foundations in frozen ground. A series of laboratory direct shear tests on the adfreezing interface between silt and concrete are performed to understand the mechanical behaviors of the foundation-frozen soil interface. The results show that the temperature, moisture content and normal stress significantly affect the adfreezing strength and its bond healing. The small displacements between foundation and frozen soils may result in dramatically less loss in the adfreezing strength. The breaking of ice bond decreases the cohesion, and the increasing surface roughness results in the increase in the internal frictional angle. The increase in the adfreezing strength due to the increasing internal frictional angle is significantly smaller than the loss of the adfreezing strength resulting from the decrease in cohesion. The adfreezing bond is an important parameter to reasonably design and construct the frozen ground foundation. The temperature, moisture content and normal stress can also affect the tangential frost heave force via the influence on the adfreezing bond. However, the Chinese standard for the foundation design in frozen ground does not consider the influence of these factors, which may lead to the instability of foundation or economic loss.