单轴压缩下混凝土孔洞内壁表面电位特征

Electric potential of the hole wall of concrete under uniaxial compression

通过建立的孔洞混凝土表面电位测试系统,测试了含孔洞混凝土内壁单轴压缩下的表面电位变化特征。结果表明,混凝土在受载破坏过程有表面电位产生,载荷前期表面电位随载荷的增大而增强,载荷增长越快,电位幅值变化越大;电位信号变化较载荷具有超前性,混凝土主破裂时电位波动最剧烈;电位信号的突增和电位幅值增长率的突变可作为孔洞混凝土破裂的前兆特征。通过对孔洞混凝土内壁表面电位的研究,加深了对孔洞混凝土破坏微观机理的认识,为将来用表面电位技术监测巷道及隧道围岩的稳定性做了基础性实验研究。

The experimental system for collecting electric potential was founded. The research was made on the characteristic of surface potential signal during the deformation and fracture of concrete with hole. The results show that electric potential signal generates during the process,meanwhile,at the initial stage of loading,the surface potential is enhanced with the increasing of load,the larger the load the higher the potential amplitude becomes,electric potential changes advancer than load and extreme volatility during concrete main rupture. The sudden increase in potential signal amplitude and the growth rate of potential mutations can be used as a precursor to cracking of hole concrete.Through the study of variation rules of electric potential during hole concrete failure,it can deepen our understanding in the concrete micro-fracture process which may provide basic experimental research results for monitoring tunnel rock mass stability and construction safety by using the electric potential technology.