岩土超声波测试研究进展及应用综述

超声波在岩土介质中传播时携带了许多与岩土物理力学性质有关的信息,这些信息可综合反映到声学参数如超声波速、衰减系数、波形、频率、频谱及振幅等的变化上,根据这些参数可反演得到岩土体的物理力学指标及细观结构特征,从而解决一系列的岩土工程问题。首先对超声波无损检测可以解决的岩土工程问题进行了概述。其次系统地阐述了土体和岩石(体)超声试验的研究进展:土体强度参数声学特性的试验研究、土体微结构参数的超声探测、岩石强度参数的超声测试研究、超声波速在岩石破裂方面的应用研究、超声波声波衰减在岩石材料中的应用、超声波速度和衰减各向异性的研究及超声波流体流动试验的研究。最后,笔者将超声波测试拓宽到土石混合体研究领域,探讨了不同含石量试样的波速和衰减规律,以及损伤声学参数对试样在单轴压缩作用下裂纹扩展的细观损伤特性的研究,更进一步说明了土石混合材料即不有别于土也不同于岩的特殊性。在以上研究基础上,基于超声波岩土试验国内外研究动态的总结,对其未来的发展趋势进行了展望。

REVIEW OF REASEARCH PROCESS AND APPLICATION OF ULTRASONIC TESTING FOR ROCK AND SOIL

When the ultrasonic wave propagates in rock and soil, it carries lots of information related to the physical and mechanical properties of geotechnical medium. The information can be integrated and reflected in change of a series of acoustic parameters including ultrasonic velocity, attenuation coefficient, waveform, frequency, frequency spectrum and amplitude. Based on these parameters, the physical and mechanical properties of rock mass and mesoscopic structure characteristics can be investigated indirectly, so as to solve a series of geotechnical engineering problems. In this paper, the geotechnical problems which can be resolved by ultrasonic nondestructive testing are summarized. A systematic review is performed on the progresses of ultrasonic testing in soil and rock, which include the work of soil strength parameters, the microstructure of soil parameters, the obtaining of rock strength parameters by ultrasonic test, the rock fracturing mechanism, the application of ultrasonic wave attenuation in rock materials, the anisotropy of ultrasonic velocity and attenuation and research of ultrasonic test in flow test. Finally, the ultrasonic test is broadened in the research field of rock and soil aggregate. Wave velocity and attenuation law with specimens of different rock percentage are discussed. Also during compressive test, the meso-damage characteristics are analyzed with acoustic parameters, to illustrate that the rock and soil aggregate which is not only different from soil but also different from rock. Based on the above research, the development tendency of ultrasonic test is also prospected.