Development and performance testing of centrifugal model test equipment for frozen soil

The centrifugal model test is an effective method to solve the problem of frozen soil engineering in a long time span. But the refrigeration end of the existing centrifugal model test devices can only control the temperature boundary, and can not form a continuous freezing wall in the soil body. In order to simulate the freezing process of tubular cold source in soil during artificial formation freezing, a set of frozen soil centrifugal test equipment using semiconductor refrigeration and controlled liquid nitrogen freezing is independently designed based on the TJ-150 geotechnical centrifuge of Tongji University. Ouring the test process, the semiconductor refrigeration equipment can realize the control of the boundary temperature of the freezing wall, and the liquid nitrogen freezing devices can realize the stable storage and fixed point transportation of liquid nitrogen. Based on this set of test equipment, a centrifuge micro-pore pressure static penetration test is carried out to explore the change rules of permeability coefficient of soft soil before and after freeze-thaw. The performance of the devices is tested under 15g centrifugal super-gravity, and the feasibility of measuring the permeability coefficient of soft clay before and after freeze-thaw by using the centrifuge micro-pore pressure static penetration test devices is preliminarily explored.