尺寸效应对结构面抗剪强度影响研究

岩体中存在的结构面对岩体的物理力学性质有着重要的影响，而尺寸效应是结构面的物理力学性质的重要影响因素。为研究尺寸效应对岩体结构面强度与变形的影响，对岩芯岩样进行扫描，根据数据建立模型，对不同尺寸岩样进行直剪试验的数值模拟，同时进行法向应力下的直剪试验，对结构面在剪切应力作用下的抗剪强度曲线以及不同尺寸结构面的剪切特性进行深入研究，得出结构面抗剪强度与结构面尺寸之间的关系，并建立抗剪强度经验公式。结果表明:随着结构面尺寸的增大，结构面抗剪强度也随之增大，当达到一定尺寸后，抗剪强度开始稳定，定义此临界尺寸为表征单元面，在确定结构面抗剪强度时，结构面尺寸不得低于表征单元面面积, 本文中岩样表征单元面面积为0.384 8 m2。  

Study of Impaction of Size Effecton Structural Plane Shear Strength

The size effect is one of the most important factors of structural plane, which has a significant impact on the physical and mechanical properties of rock mass. The experiment was conducted to study the effect of size effect on the strength and deformation of the structural plane of rock mass by scanning the core of rock specimens, modeling with data and using numerical simulation of direct shear tests on different sizes of rock samples. Meanwhile, an in-depth study of the strain curve of the structural plane under the effect of shear stress and substantial properties of shear deformation of different structural plane sizes was conducted by taking the direct shear tests under normal stress, the shear strength of structural plane had substantial correlation with its size effect, then the shear strength of empirical formula was established. Resuhs indicated that the shear strength of structural plane increased with its increase in size, and began to stabilize when reaching a certain size, then the critical size was defined for representative elementary area. When determining the shear strength of structural plane, the structural plane size shall not be less than the area of representative elementary area. In this article, area of representative elementary area was 0. 384 8 m^2.