绿片岩的单轴压缩各向异性蠕变试验研究

Anisotropic Creep Test of Greenchist Under Uniaxial Compression

摘要:

通过对锦屏二级水电站辅助交通洞的绿片岩单轴压缩蠕变特性试验,研究了轴向荷载方向与层理之间的不同关系对瞬时应变、应力应变关系、轴向应变速率、衰减蠕变持续时间和蠕变破坏机理的影响.研究结果表明：在相同低应力水平下,垂直于层理时的瞬时应变增量大于平行于层理时的瞬时应变增量,而在相同较高应力水平下垂直于层理时的瞬时应变增量小于平行于层理时的瞬时应变增量；同等应力水平条件下,垂直于层理时的轴向应变速率和衰减蠕变持续时间均小于平行于层理时的轴向应变速率和衰减蠕变持续时间.同时,当轴向荷载垂直或者平行于层理时,应力应变关系曲线均出现了压密、弹性变形、裂纹扩展和峰后破坏阶段,且蠕变破坏类型均属于脆性破坏.

Abstract:

The uniaxial creep tests of green schist from auxiliary tunnel at Jinping second stage hydropower station were carried out.An analysis was made of the influence of relationship between axial loading orientation and bedding plane on instantaneous strain,stress strain relation,axial strain rate,time duration of transient creep phase and creep breach mechanism.The instantaneous strain increment when axial loading orientation is perpendicular to bedding plane is larger than that when parallel to bedding plane under the same lower stress level,while,the result is on the contrary under the same higher stress levels.The axial strain rate and time duration of transient creep phase when axial loading orientation is perpendicular to bedding plane is smaller than that when the parallel to bedding plane under the same stress level.Meanwhile,the stress strain relation curve has initial crack closing stage,elastic deformation stage,crack extending stage and post failure stage when axial loading orientation is perpendicular or parallel to bedding plane,and the creep failure patterns under two kinds of conditions are both brittle.