隧道砂岩破裂过程的电位信号研究

Electrical potential signals during rupture process of tunnel sandstone

研究了砂岩破裂过程的电位信号规律及其破坏的电位前兆特征，结果表明，砂岩在破裂过程中有电位信号产生，电位信号与试样的变形破裂呈现良好的对应关系；电位信号对加载初期的变形破坏及裂纹的生成比较敏感，声发射在初期比较平淡，在加载后期电位幅值略有降低，而声发射信号大量增加；在试样的加速变形过程中在应变峰值的70％-97％范围内有强脉冲电位信号出现，电位信号的峰前突增可以作为砂岩破坏的前兆特征。通过研究煤岩体破裂过程的电位信号变化规律，可以加深对岩石破裂微观过程的认识，为将来利用电位技术监测隧道岩体稳定性及隧道施工安全提供了基础性研究结果。

In this paper, the variation rules of electric potential signals during fracture process of tunnel sandstone and the precursor characteristics before rupture were studied. The results show that the elec- tric potential signals will be generated in the fracture process of sandstone, and there is close corre- sponding relation between the electric potential signals and deformation and fracture of the samples. Meanwhile, the potential signals are more sensitive to the deformation and failure, and the propagation of cracks at the initial stage of loading, while the acoustic emission is fewness, and the potential ampli- tudes slightly reduce at the later stage of loading while the acoustic emissions increase abundantly. Within 70%-97% of the peak strain in the process of accelerating deformation, there will exit strong pulse potential signals, thus, the sharply increase of potential before strain peak can be used as the pre- cursor characteristics of sandstone rupture. Through the study of variation rules of electric potential during rock failure, it can deepen our understanding in the rock micro-fracture process which may pro- vide basic research results for monitoring tunnel rock mass stability and construction safety by using theelectric potential technology.