Experimental Study on Horizontal Frost Heave Force of Deep Foundation Pit

Based on the foundation pit of a subway station in Hohhot City, the extreme cooling process was simulated according to the local climate conditions. Through indoor model experiments and numerical simulation, the distribution characteristics of soil temperature, frost heaving stress and the deformation law of soil and diaphragm wall under the action of freeze-thaw cycle were studied. The results show that: the outer soil temperature gradient is large, and the internal soil temperature is relatively stable and the change is relatively lag, with maximum freezing depth of the foundation pit being 1.1～1.2 m; the horizontal frost heaving force increases at first and then decreases with the depth of the foundation pit, showing a parabola distribution pattern, and the maximum value appears at the depth of about 8～10 m; under the extreme climate conditions, the maximum horizontal frost heaving force reaches 120～140 kN. It has a great influence on the design and construction, and provides reference for deep foundation pit engineering in severe cold area.