冻结粉质黏土声学特性与物理力学性质试验研究

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。

TESTING AND STUDY ON THE RELATIONSHIP BETWEEN ACOUSTIC CHARACTERS AND PHYSICO-MECHANICAL PROPERTIES OF FROZEN SILTY CLAY

In order to study the relationship between acoustic characters of frozen silty clay and its physics mechanics properties，ultrasonic tests of frozen silty clay were conducted，and measured its tensile and compressive strength under various negative temperatures. The influence of temperature，water content and dry density on ultrasonic wave velocity and the relationship between wave velocity and strength of frozen silty clay were analyzed base on the tests. Test and analysis results indicated that，ultrasonic wave velocity rapidly changes in the temperature range of -1℃ to -7℃. There exists critical water content and the value is 16.03%. Ultrasonic wave velocity increases firstly and then decreases with an increase of water content. Under the same water content，wave velocity increases linearly with an increase of dry density. Three dynamic elastic mechanical parameters of frozen silty clay were obtained from the measured wave velocities and specimen densities based on elastic theory and its change trends with temperature was analyzed. There exist good correlations between ultrasonic wave velocity and strength of frozen silty clay. The larger the strength and the faster the wave will be. It is found that the ultrasonic test technique can be used to test frozen soils nondestructively and lay the foundation for the prediction of frozen soil strength.