Approach to the Application of Ultrasonic Technology to Measuring Physical Properties of Frozen Soils
Approach to the Application of Ultrasonic Technology to Measuring Physical Properties of Frozen Soils
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发表时间：
2001
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通讯作者：
Shenghao Yu
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作者：
Shenghao Yu
超声波在介质中的传播反映了介质的动态特性，而介质的动态特性又取决于介质的物理性质。由于超声波技术具有操作简单、测量速度快、样品不受干扰等优点，可以直接测量冻土动弹性常数，间接测量冻土的某些物理性质。对兰州黄土进行了超声测试，以获得冻土的动力特性(包括杨氏模数、剪切模数和泊松比)。通过对冻结兰州黄土在不同温度下的超声波声速和抗压强度试验，建立了声速与抗压强度之间的关系。不同混合轮胎粉的Tomakomai粉土也在特定的温度下进行了类似的试验，以确定抗压强度与超声波速度之间是否存在关系。为了进一步研究未冻水含量对冻土声速的影响，对冻结玻璃微珠进行了超声测试，以确定超声速度对未冻水含量的响应。试验结果表明，通过测量冻土的超声波波速，可以估计冻土的强度随单一因素(如温度或混合轮胎含量)的变化。因此，超声速与不同温度下冻土的未冻水含量有很好的相关性。这些经验关系表明，超声波技术有可能应用于冻土物理力学性质的估算。
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.