论文部分内容阅读
岩石强度的载荷速率相关性与岩石的时间相关性特性及粘弹性性质密切相关,而且强度的载荷速率相关性越大,越容易发生蠕变破坏。对于坡体来说,如果构成坡体的岩石的时间相关性很显著,那么即使在比较低的应力下仅施加一点载荷,也容易发生变形。针对三峡库区周边滑坡多发,采集了组成滑坡坡体的4类主要岩石-泥岩、灰岩、泥质砂岩及砂岩。通过室内岩石力学强度试验,获得了不同岩石的强度特性曲线及表示载荷速率相关性的参数n。利用一个试件通过载荷速率交替变换获得了不同应变速率下的应力-应变曲线,从而根据强度的变化率不仅获得了峰值强度的载荷速率相关性,而且还求得了残余强度的载荷速率相关性。在单轴压缩试验中,残余强度的n值与峰值强度的n值有较大的差异,但在三轴压缩试验中两者的差异却不太明显。而且在气干状态下,不管是峰值强度还是残余强度的n值均随着围压的增加而增加。
The correlation of rock strength loading rates is closely related to the time-dependent and viscoelastic properties of rocks, and the greater the correlation of strength loading rates, the more likely creep damage occurs. For slopes, if the time-dependent nature of the rocks that make up the slope is significant, deformation is prone to occur even with only a small load applied at lower stresses. According to the frequent occurrence of landslides around the Three Gorges Reservoir Area, four types of major rocks, mudstone, limestone, argillaceous sandstone and sandstone, which make up the landslide slope are collected. Through indoor rock mechanical strength test, the strength characteristic curve of different rocks and the parameter n, which shows the correlation between the loading rates, are obtained. The stress-strain curves at different strain rates were obtained by alternating the load rate using a specimen. The dependence of load strength on peak strength was obtained according to the rate of change of strength, and the dependence of load strength on residual strength was obtained. In the uniaxial compression test, the value of n of residual strength has a great difference from the value of n of peak strength, but the difference between the two is not obvious in the triaxial compression test. Moreover, under the air-dry condition, the value of n, whether peak intensity or residual strength, increases with increasing confining pressure.