冻结粉质黏土声学特性与物理力学性质试验研究

EXPERIMENTAL STUDY ON ACOUSTIC CHARACTERISTICS AND PHYSICO-MECHANICAL PROPERTIES OF FROZEN SILTY CLAY

为分析冻结粉质黏土的声波参数与其物理力学性质之间的关系,进行冻结粉质黏土的超声波测试,同时测定了其在不同温度下的抗拉、抗压强度。基于试验分析温度、含水率和干密度等对冻土波速的影响以及波速与强度的关系。结果表明:土样在-1℃^-7℃范围内,波速变化尤为剧烈;存在一个临界含水率16.03%,使波速随含水率的增加呈先增加后减少的趋势;在含水率相同的情况下,波速随干密度的增加呈线性增加;通过波速计算得到冻结粉质黏土的3个动弹性力学参数,并分析这些参数随温度的变化趋势;冻土声波波速与强度呈现出良好的相关性,冻土的强度越大,声波波速越高。因此,可利用声波测试技术对冻土进行无损检测,为冻土强度的预测奠定基础。

In order to study the relationship of the acoustic characteristics and the mechanical properties of frozen silty clay,ultrasonic tests on frozen silty clay were conducted and the tensile and compressive strengthes were measured under various temperatures below zero. Based on the testing results,the influence of temperature,water content and dry density on the ultrasonic wave velocity was analyzed and the relationship between the wave velocity and the strength of frozen silty clay was discussed. The ultrasonic wave velocity changed rapidly in the temperature range of-1 ℃ to-7 ℃. There existed a critical water content of 16.03%. The ultrasonic wave velocity increased firstly and then decreased with the increase of water content. Under the same water content,the wave velocity increased linearly with the increase of dry density. Three dynamic elastic mechanical parameters of the frozen silty clay were obtained from the measured wave velocities and specimen densities based on elastic theory and their variation with temperature was analyzed. There existed a good correlation between the ultrasonic wave velocity and the strength of frozen silty clay. The larger the strength,the faster the wave.