高含冰量冻结粉土单轴受压损伤特性试验分析

为了研究高含冰量冻结粉土的应力-应变关系及结构的内部损伤演化过程,利用SOMATOM-PLUS X射线螺旋CT机对-1、-2、-4℃下的冻结粉土进行了单轴压缩实时CT扫描试验,探讨了温度对高含冰量冻结粉土的宏观力学性能及微观损伤演化过程的影响。通过试验结果可以看出:冻结粉土的应力-应变关系曲线大致经历线弹性变形阶段、损伤演化阶段与峰后软化阶段;高负温下温度对冻结粉土初始弹性模量影响不是很明显,而对冻结粉土强度的影响则比较大;温度从-1℃降到-2℃,强度大约可以提高63%,而从-2℃降到-4℃,强度可以提高约为36%;CT扫描各层初始密度损伤并不完全相同,但各层密度随着应变变化的趋势大致相同,中环、全区的密度随着应变的增加而减小,外区密度则随着轴向应变的增加而增大。

Experimental analysis of damage of ice-rich frozen silt under uniaxial compression

The CT real-time tests were carried out to investigate the macro-mechanic properties and meso-damage mechanism of frozen silt at temperatures of -1℃, -2℃ and -4℃ under uniaxial compression. The compressive strength, stress-strain relationship, and the damage evolution characteristics of frozen silt were obtained. The test results show that the stress-strain curves of frozen silt mainly includes three parts: the linear elastic deformation part, the damage evolution part, and the post-peak strain softening part; the compressive strength of ice-rich frozen silt is sensitive to temperature; but the initial elastic moduli of frozen silt have little difference at different temperatures; with the temperature decreasing from -1℃ to -2℃, the strength could be enhanced about 63%, however, with the temperature further decreasing from -2℃ to -4℃, the strength could only be enhanced about 36%; the initial density damages at different slice of samples are different. The density in whole zone and medium ring zone of samples decreases with the increase of axial strain; but increases with increasing in axial strain in exterior zone.