为了解决负温条件下的冻胀问题,进行了一系列的试验。试验中把砂土、砂壤土和粘土分别烘至本身最优含水量的60％,对其余40％用浓度20％的亚硝酸钠水溶液补充,使每一种土的总含水量接近最优值,然后压实制成试样,放在-25℃冷冻箱里保持6昼夜。试验结果,含水量W=20％的冷冻砂土破坏瞬时的抗压强度为58兆帕;含水量W优并用NaN0_2溶液处理 In order to solve the problem of frost heaving under negative temperature, a series of experiments were carried out. Sand, sandy loam and clay were bake to 60% of the optimum water content in the experiment, and the remaining 40% were replenished with 20% sodium nitrite aqueous solution to make the total water content of each soil close to the optimal value , And then compacted into a sample, placed in -25 ℃ freezer for 6 days and nights. As a result, the instantaneous compressive strength of frozen sand with a water content W of 20% was 58 MPa; the water content W was excellent and treated with NaN0 2 solution