岩体结构面劣化的力学行为及互补模型研究

Structure plane plays a control role in the deformation and stability of rock mass. The mechanical properties of structure plane deteriorate obviously under loading. The artificial stiffness parameters are usually introduced to describe the mechanical behavior, and the iteration non-convergence often appears during the process of nonlinear simulation. By means of the direct shear test and post-peak shear cyclic loading and unloading test of rock structural plane with different waviness and normal stress, and the deterioration law of strength and deformation characteristics have been revealed, and the constitutive model reflecting the deterioration behavior will be derived. Considering the complementary relationship between normal and tangential contact, the equivalent complementary model that eliminates artificial stiffness parameters and considers the deterioration of structure plane with according algorithm is proposed. The smooth Fischer-Burmeister function is selected to build the system of equilibrium equations, and the convergence problem from the conventional opening and closing iterative algorithm can be easily solved. By comparison with existing methods, the efficiency of proposed model and algorithm mentioned above can be verified. This work is expected to deepen our understanding of the deformation and strength characteristics of the structural plane, enrich the constitutive theory and analysis of algorithms of the structural plane and the research results will be utilized for rock slope stability evaluation.

结构面对岩体的变形和稳定起着控制作用。结构面力学性质在荷载作用下存在明显的劣化现象，描述其力学行为时通常包含人为设置的刚度参数，且非线性模拟过程中经常出现迭代收敛性问题。采用不同起伏度和荷载组合下的室内结构面剪切试验和峰值后区多次切向加卸载试验，揭示其强度劣化规律和变形特性，建立能够反映结构面劣化行为的本构模型。分析结构面法向和切向接触的互补关系，提出消除人为刚度参数和考虑结构面劣化特性的等价互补模型及相关算法；采用光滑性良好的Fischer-Burmeister互补函数建立系统平衡方程，解决互补模型的强非线性和常规开闭迭代算法引起的收敛性问题。进一步通过与现有方法的对比，验证上述模型和算法的高效性。本项工作有望加深对岩体结构面变形与强度特性的认识，丰富结构面本构理论与分析算法。研究成果将用于岩质边坡稳定性评价。

针对目前描述岩体结构面力学行为时通常包含人为设置的刚度参数，且非线性模拟过程中经常出现迭代收敛性问题，本项目开展了结构面法向和切向接触的互补模型及算法研究，拓展至复杂边坡的多级滑面搜索及矢量和安全系数计算。研究成果具有重大的理论意义和工程价值。本项目采用不同起伏度和荷载组合下的室内结构面剪切试验和峰值后区多次切向加卸载试验，揭示其强度劣化规律和变形特性，建立能够反映结构面劣化行为的本构模型。分析结构面法向和切向接触的互补关系，提出消除人为刚度参数和考虑结构面劣化特性的等价互补模型及相关算法；采用光滑性良好的Fischer- Burmeister互补函数建立系统平衡方程，解决互补模型的强非线性和常规开闭迭代算法引起的收敛性问题。并在此基础上开展了考虑强度参数劣化过程的边坡多滑面搜索和矢量和安全系数的求解。项目的主要研究成果如下：(1)开展室内直剪试验，分析了剪切过程中强度参数的弱化现象；(2)接触面互补模型的建立及应用。根据接触面的法向和切向关系，分别建立了相应的互补模型并建立了含有互补函数的方程组，提出求解方法。开展了算例验证和应用；(3)基于应变软化规律，开展了多级边坡的多个滑动面搜索和矢量和安全系数的劣化研究，并进行了滑面搜索及工程应用。