冻融作用对黏土力学性能影响的试验研究

Experimental study on effects of freezing and thawing on mechanical properties of clay

为揭示冻融作用对黏土力学性能的影响规律,对原状土及不同冻融条件下的融土进行了压缩试验和固结排水剪切试验。试验结果表明:黏土冻融后,压缩系数大于原状土的压缩系数;封闭型冻融时,冷端温度越低、含水率越大,则压缩性的变化越大;融化温度对融土压缩特性基本无影响;冻融对不同干密度的重塑黏性土具有双向作用,使松散的低密度土压缩性减小,密实的高密度土压缩性增大。黏土冻融后,黏聚力降低,内摩擦角增大;封闭型冻融时,冷端温度越低,内摩擦角变化越大;融化温度对融土的强度影响很小。

In order to study the influence of freezing and thawing on mechanical properties of clay, 1-D compression tests and consolidation-drained shear tests are carried out on intact soil and the corresponding thawed soil under different freezing and thawing conditions. The experiments show that after freezing and thawing, the coefficient of compressibility is larger than that of the intact soil. The lower the temperature at the freezing end and the larger the water content are, the larger the changes of the compressibility are. There is no effect of the melting temperature on the compressibility of the thawed soil. The freezing and thawing has different influences on the remoulded soil with different original densities, and it will make the compressibility of soils with smaller original densities decrease, while that of the soils with larger original densities increases. After freezing and thawing, the cohesion decreases, and the internal friction angle increases. For the closed freezing and thawing, the lower temperature of the freezing end leads to larger changes in the internal friction angle. The melting temperature has little effect on the strength of the thawed soil.