超声波法测定冻土动弹性力学参数试验研究

运用UVM -2型声速测定仪 ,测定了不同含水率的冻结砂土、冻结黄土和冻结黏土在不同温度下的超声波波速 (纵波波速和横波波速 ) ;根据弹性理论 ,利用所测得的超声波波速 ,计算了被测冻土试样的动弹性力学参数 (动弹性模量E、动剪切模量G和泊松比 μ)。计算结果表明 :冻土的动弹性模量和动剪切模量随着温度的降低而增加 ,它们之间的规律可用一个统一的方程来描述 ;冻土的动泊松比随着温度的降低而减小 ;在低含水率范围内的冻结黄土 ,其动弹性模量和动剪切模量随含水率的增加而增加 ,在高含水率范围内的冻结黏土 ,它们则随含水率的增加而减少 ;冻土的动泊松比随含水率的增加而增加。

Study on experimental determination of the dynamic elastic mechanical parameters of frozen soil by ultrasonic technique

Velocities of the ultrasonic (dilatational and shear) waves in frozen fine sand, silt (loess) and clay with different water contents were measured at different temperatures by UVM-2 Ultrasonic Measuring System. Then, the dynamic elastic mechanical parameters (dynamic elastic modulus E, dynamic shear modulus G and Poisson’s ratio μ) of the frozen soils tested were calculated in terms of elastic theory based on the measured ultrasonic wave velocities.The calculated results show that both of dynamic elastic modulus and shear modulus of the three types of frozen soils increase with decreasing temperature,and their relations can be described by same formula. The Poisson’s ratios of the frozen soils tested increase with increasing temperature. Both of the dynamic elastic modulus and shear modulus of frozen silt and clay with low water content increase with increase of water content;whereas the moduli of those with high water contents decrease with increasing water content. The Poisson’s ratios of the frozen silt and clay increase with increasing water content in the wide range of water contents tested.