受载煤体全应力-应变过程电阻率响应规律

为了研究煤体变形破坏过程电阻率变化特征,利用自建的受载煤体电阻率实时测试系统,对单轴压缩过程煤体应力、应变及电阻率进行了测试,分析了全应力-应变不同阶段煤体电阻率响应规律及变化机制。研究结果表明:煤体全应力-应变过程中,扩容现象发生时电阻率变化趋势出现突变,由下降转为上升,呈不规则"V"字形变化;在扩容发生前的压密阶段和弹性阶段,电阻率的变化由孔隙裂隙的闭合及应力作用决定,扩容的发生使得煤体在塑性阶段电阻率总是呈上升趋势,煤体进入破坏阶段后电阻率进一步上升。通过对煤体电阻率进行连续实时监测,可将电阻率变化规律作为前兆信息,以反映煤体失稳破坏前的扩容突变现象。

Resistivity response in complete stress-strain process of loaded coal

In order to study the coal resistivity variation characteristics in deformation and destruction process，the stress，strain and the resistivity of coal during uniaxial compression process were tested using self-built real-time testing system of loaded coal resistivity.Furthermore，the resistivity response rules and variation mechanism at different stages of complete stress-strain were analyzed.The results show that in the process of complete stress-strain of coal mass，the resistivity undergoes the process from descending to ascending，which shows an irregular “V” variation pattern when dilatancy occurs.In the densification and flexibility phases before dilatation occurrence，the variation of resistivity is determined by the closure of coal fissures and stress action.Because of dilatation，the coal resistivity always shows an increasing tendency at the plastic stage.After the peak stress，the coal body enters into a failure stage and the coal resistivity is further improved.Through a real-time monitoring on coal resisitivity，the variation rules of resistivity can be deemed as precursory information so as to reflect the dilatation and sudden change before the coal body reaches a failure，which can provide a new technological mean for forecasting the dynamic disaster of coal and rock.