高温-高含冰量冻结黏土强度试验研究

为研究高温-高含冰量冻土的强度特性，分别开展了不同温度、不同含水率的冻结黏土单轴无侧限抗压强度试验。分析了高温-高含冰量冻结黏土在单轴压缩试验过程中的破坏类型、应力-应变关系；单轴抗压强度与温度、含水率之间的关系以及饱和冻结黏土单轴抗压强度对温度的敏感性-含水率关系。研究结果表明：当温度低于-0.9 ℃时，高温-高含冰量冻结黏土存在最不利含水率，在相同的温度条件下，该含水率状态下冻土抗压强度最小；当温度高于-0.6 ℃时，高含冰量冻土随含水率的增加，单轴抗压强度增大。

Experimental research on strength of warm and ice-rich frozen clays

In order to study the strength character of warm and ice-rich frozen soil, a series of uniaxial compressive strength tests of frozen clays with water contents of 20 %, 40 %, 60 %, 90 %, 120 % at temperatures of –0.3 ℃, –0.6 ℃, –0.9 ℃, –1.5 ℃, –5.0 ℃ were conducted respectively. The test results indicate that: 1) the type of stress-strain curves for the warm and ice-rich frozen clays(temperature: –0.3 ℃ to -1.5 ℃, water content: 60 %-120 % ) is strain-hardening, and the form of sample failure is plastic; 2) The compressive strength of warm frozen clay with water contents of 40 % to 90 % increases linearly with the decrease of temperature, the sensitivity of the strength of lower water content saturation frozen clay to temperature is higher than that of higher water content saturation frozen clay; at the water content of 120 %, the amplitude of the increase in compressive strength decreases with decreasing temperature; 3) when the temperature of the warm frozen clay is lower than -0.9 ℃, there is a most disadvantageous water content (at the same temperature, the compressive strength of the frozen soil at this water content is the lowest); when the temperature of the warm frozen clay is higher than -0.6 ℃, the strength increases with water content increasing.