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对石英云母片岩进行三轴压缩蠕变试验,研究丹巴水电站石英云母片岩的三轴蠕变特性及其各向异性特性。按轴向荷载与层理面关系加工成平行组和垂直组2组试件,开展分级加载方式进行不同围压条件下的蠕变试验。试验研究表明,石英云母片岩具有蠕变特性,包括瞬时变形、衰减蠕变、稳定蠕变和加速蠕变阶段;采用带Kachanov蠕变损伤律的蠕变模型来描述石英云母片岩的蠕变特性,并进行蠕变参数辨识,拟合结果显示此模型能很好地描述石英云母片岩的蠕变特性;根据试验结果获得2组试件的长期屈服强度、破坏形态、瞬时变形参数和稳定蠕变速率,分析表明石英云母片岩的蠕变力学特性具有明显的各向异性特性。层理面与轴向荷载垂直的试件较层理面与轴向荷载平行的试件的强度、弹性剪切模量、体积模量和黏性系数相对较大,表现出较高的抗变形和抗破坏能力;平行组以剪切破坏为主,垂直组破坏时出现侧向鼓胀现象,显示出延性破坏的特点;2组石英云母片岩试件的瞬时应变量和稳定蠕变速率都随着应力水平的提高而增大。
The triaxial compression creep test of quartz mica schist was carried out to study the triaxial creep and anisotropy of quartz mica schist at Danba hydropower station. According to the relationship between axial load and bedding plane, two groups of specimens of parallel group and vertical group were processed, and the creep test under different confining pressure was carried out by graded loading method. Experimental studies have shown that quartz mica schist has creep characteristics including instantaneous deformation, decay creep, stable creep and accelerated creep. The creep model with Kachanov creep damage law is used to describe the creep characteristics of quartz mica schist, And the creep parameters are identified. The fitting results show that this model can describe the creep characteristics of quartz mica schist well. According to the test results, the long-term yield strength, failure mode, instantaneous deformation parameters and stable creep rate The analysis shows that the creep properties of quartz mica schist have obvious anisotropy. The specimens with laminar plane and axial load perpendicular to each other had higher strength, elastic shear modulus, bulk modulus and viscous coefficient than those with laminar plane parallel to axial load, showing higher resistance to deformation And anti-sabotage ability. The parallel group is dominated by shear failure and lateral bulging occurs when the vertical group is damaged, which shows the characteristics of ductile failure. The instantaneous strain and steady creep rate of the two groups of mica-schist samples are both Increased stress levels.