绿片岩各向异性蠕变特性试验研究

EXPERIMENTAL INVESTIGATIONS ON STRUCTURAL ANISOTROPY ON CREEP OF GREENSCHIST

为了解锦屏二级水电站引水隧洞绿片岩的各向异性流变力学特性,通过对层状脆性绿片岩试件进行单轴压缩蠕变试验,研究脆性层状岩石材料的各向异性蠕变规律。按层理面倾角大小共加工6个试件,分级加载均为4个应力水平,最大值与初始地应力接近。试验结果表明,绿片岩试件蠕变曲线存在瞬时应变、衰减蠕变和稳定蠕变,未出现加速蠕变阶段。根据试验结果得到瞬时弹性模量和稳定蠕变阶段的蠕变速率。分析表明,绿片岩试件的瞬时弹性模量随着应力水平的提高而提高,并趋于稳定,其中层理倾斜的试件瞬时弹性模量更高;蠕变速率随着应力水平的提高而提高,并随着层理面倾角的增大而增大,层理面倾角接近材料的破裂角时,试件的轴向蠕变速率最大。

In order to study the time-dependent deformation behavior of bedding anisotropy green schist of Jinping II hydropower station,this paper investigates the creep behavior of brittle bedding anisotropy rock by uniaxial compression creep experiments in laboratory. Six specimens were prepared with different inclination angles of bedding planes. Loading stress levels were graded 4 classes,and the maximum value of them were all approximately equal to the existing maximum initial geostress. All the strain-time curves of specimens did not exhibit the accelerated creep stage. The instantaneous elastic modulus and steady-state creep rate of specimens were obtained and analyzed based on the experiments data. The results show that the instantaneous elastic modulus of the specimens increases with the increment of stress level;and they were higher when the bedding planes are oblique to the compression direction;and the steady-state creep rate of the specimens increase with the increment of both stress level and the inclination angle of bedding planes;it reaches the maximum value with the inclination angle of the specimen close to the failure angle of rock.