超声波技术在冻土物性测试中的应用探讨

超声波在冻土中的传播特性反映了冻土材料的动力学特征，利用超声波速度测试技术可以直接测试冻土的动力学弹性参数，实验结果表明，冻土的单轴压缩强度与冻土的超声波速度在单一影响因素改变时存在良好的相关关系，利用这种相关性，有可能采用超声波无损测试技术来估计冻土的强度，冻土的未冻水含量明显影响着冻土中超声波的传播速度，实验结果表明，超声波速度与未冻水含量之间存在很好的函数关系，它提示了超声波速度用于冻土未冻水含量测试的可能性。

Approach to the Application of Ultrasonic Technology to Measuring Physical Properties of Frozen Soils

The propagating of ultrasonic wave in a media reflects the dynamic properties of the media, while the dynamic properties should depend on its physical properties. Due to the advantages of the ultrasonic technologies, such as easy operation, fast measurement, and non disturbing sample, it is possible to directly measure the dynamic elastic constants of frozen soils, and indirectly measure some physical properties of frozen soils by the technique. Ultrasonic tests of Lanzhou Loess were carried out to obtain dynamic properties of frozen soils (including Young's modulus, shear modulus and Poisson's ratio). Experiments of ultrasonic wave velocity and compressive strength in frozen Lanzhou Loess under different temperatures were conducted to establish the relationship between ultrasonic velocity and compressive strength. Similar test for Tomakomai Silt with different mixed tire powder was also conducted at a unique temperature to qualify the existence of a relationship between compressive strength and ultrasonic velocity. As a sequent study in the effect of unfrozen water contents on the ultrasonic velocities of frozen soil, ultrasonic tests for frozen glass bead were conducted to confirm the response of the ultrasonic velocity to the unfrozen water content. Experimental results indicated that the strength of frozen soil changing with a single factor (such as temperature or mixed tire fraction) could be estimated by measuring its ultrasonic wave velocity. Thus ultrasonic velocity have a good relation to the unfrozen water content of frozen soil under different temperatures. All of the empirical relations imply that the ultrasonic technique may be possibly applied in estimation of physical and mechanical properties of frozen soils.