三峡库区岩体天然结构面抗剪性能试验研究

Study on property of rock mass discontinuity shear strength in Three Gorges reservoir area

采用自制的试验装置对取自三峡库区的含天然结构面的岩块试件进行压剪试验,通过对4组试件进行不同正压力及不同含水量(天然状态与饱水状态)下的剪切试验,绘制出其相应的变形和强度曲线,并对这几组曲线进行了对比分析。试验结果表明:岩块中结构面的抗剪强度不仅与岩块所受法向应力的大小有关,而且与岩块含水量的大小有关,即结构面抗剪强度的大小随着法向应力的增大而增大,又随着含水量的增大而减小;最后,运用最小二乘法对该结构面的抗剪参数进行了求解,且与推荐值进行了比较,对比发现二者基本吻合,说明该试验装置与试验方法在实际工程应用中是可行、有效的。

By using home-made shear equipment, the shear tests of rock mass which has natural discontinuities from the Three Gorges reservoir area are carried out under different states; the deformation and intensity curves of different models are drawn. After analyzing the experimental data we conclude that the shear strength of discontinuity is relevant not only to positive stress but also to water content of the discontinuity of the rock mass; that is, the shear strength increases with the increase of positive stress and decreases with the increase of water content. Finally, we compare the shear strength parameters with the theoretical data, and find the two groups of data are consistent. This paper also proves the experimental device and method are feasible and valid in engineering application.