贯通节理砂岩峰后变形试验研究及其在隧道支护中的应用

深部资源开发中地下硐室围岩稳定控制必须面对峰后碎裂岩体的变形和破坏问题,但目前对峰值强度后的变形特征和强度特性研究不足,认识不充分,常导致大体积塌方、大变形等重大工程事故。采用RLW-1000型岩石三轴伺服刚性机对不同围压贯穿裂隙圆柱体标准试件进行常规三轴压缩试验,分析裂隙岩体在不同围压下裂隙岩体的峰后强度和变形特性。试验结果表明:裂隙试件的峰值强度,残余强度和峰值应变基本上是随着围压的增大而增大;围压越小,裂隙岩石峰后扩容现象越明显,岩石扩容随围压增大而减小,且岩石可塑性和围压共同影响岩石扩容。结合试验结果分析发现将峰后非连续体变形控制在残余强度的初始阶段,能以相对较低的支护阻力有效控制过高的破裂膨胀变形发生,保证隧道围岩的稳定。

Experimental study of post-peak deformation of sandstone with pre-existing transfixion joint and its application in tunnel support

Stability control of surrounding rock of underground caverns in deep resources development must face the post-peak deformation and failure problems of cataclastic rock mass，but the research of the post-peak deformation and strength characteristics is insufficient at the moment，so often leading to the large volume collapse，large deformation and other major projects accident.The conventional triaxial compression test of pre-existing transfixion jointed rock cylindrical standard specimen was made by using RLW-1000 type triaxial servo rigid machine in order to study the post-peak strength and deformation characteristics of fractured rock masses in different confining pressures.The results show that the peak strength，residual strength and peak strain of the fractured specimens essentially increases with the confining pressure；The smaller the confining pressure，the more obvious post-peak expansion of fractured rock，rocks expansion with confining pressure decreases，and the combined of rock plasticity and confining pressure effect rock expansion.Combined with the test results analysis found that the post-peak discontinuous deformation control in the initial stage of the residual strength，and relatively low support resistance can effectively control the excessive rupture expansion deformation，to ensure the stability of tunnel surrounding rock.