冻土动力学参数测试研究

TESTING STUDY ON DYNAMIC MECHANICS PARAMETERS OF FROZEN SOIL

冻土的动力学参数既是工程设计的依据之一,也是数值模拟时不可缺少的参数。本文分析了取自青藏铁路的两种路基土,即粉质粘土和细砂的动弹性模量和动阻尼比变化特征。试验发现,冻结粉质粘土和冻结细砂的动力学参数随频率、温度和含水量的变化规律相同。冻土的动弹性模量随频率的增加或温度的降低而增加。含水量增加时,冻土的动弹性模量先增加后降低,在饱和含水量附近达到最大。冻土的动阻尼比随频率的增加或温度的降低而减小。含水量增加时冻土的动阻尼比略有增加。

Testing study is made on dynamic mechanics parameters,including dynamic elastic modulus and dynamic damping ratio,of silty-clay and fine-sand which are sampled from the Qinghai-Tibet railway. Analysis is also performed on the relations among those parameters,frequencies,temperatures and water contents. The following test results are obtained. (1) Variation laws of dynamic mechanics parameters of frozen silty-clay and fine-sand are the same. (2) Dynamic elastic modulus of frozen soil will increase with increment of frequency or decrement of temperature. (3) While soil water content increases,dynamic elastic modulus of frozen soil will increase at first,and reach its maximum value when the soil are water-saturated. (4) Dynamic damping ratio of frozen soil decreases with increment of frequency or decrement of temperature. (5) Dynamic damping ratio increases slightly with increment of water content.