岩体结构面三维循环加载本构关系

研究岩体结构面在循环加载条件下的三维力学性质。通过对二维数值模型合理推广,建立三维本构模型。法向加卸载本构为逐步硬化的双曲线函数。切向模型基于加载为双曲线函数、卸载为线性函数的本构方程建立,并引入剪切方向角描述三维切向接触特性。考虑峰值剪切现象,以切向塑性功为主要参数,建立峰值摩擦角和剪胀角的磨损方程。以初始剪胀角和残余剪胀角为主要参数建立剪胀方程。数值计算结果与试验曲线的对比表明,该模型体现了各向异性结构面的非线性受力变形特性、表面磨损和不均匀剪胀行为,能较好模拟三维循环加载本构关系。

3-D constitutive relation for rock joints during cyclic loading

The 3-D mechanical characteristics of rock joints with cyclic loading were modeled using a hyperbolic function with gradual hardening of the joint for the loading and unloading constitutive relation. The shear loading follows a hyperbolic function, with the unloading as a linear function. The shear direction angle was used to describe the 3-D shear contact characteristics, the peak shear strength, the wear equations for the peak friction angle, and the dilation angle are defined mainly in terms of the shear plastic work. The dilation curve is composed of parabolic subsections calculated from the initial and residual dilation angles. Comparison with experimental results shows that the model describes the nonlinear deformation, the surface wear and the non-homogeneous characteristics of anisotropic rock joints and accurately represents the three-dimensional constitutive relations during cyclic loading.