【作者】 姚池；

【导师】 周创兵； Jian-Fu Shao； 姜清辉；

【作者基本信息】 武汉大学 ， 水工结构工程， 2013， 博士

【摘要】 水力耦合效应是岩石工程中的一个重要研究课题,例如在废弃物的地质填埋,高陡岩石边坡和地下厂房等工程中,水力耦合在工程安全性评价中扮演着至关重要的角色。由于不连续结构面的存在,岩体水力性质很难确定。原位试验存在着技术上的困难,且价格昂贵,使得数值模型成为刻画岩石水-力性质的一个必不可少的工具。基于离散裂隙网络模型和改进刚体弹簧法,本文提出了一种显式考虑岩体细观结构的水力耦合计算模型。本文的主要工作列举如下,(1)提出了一种用于岩石细观破坏模拟的改进刚块弹簧方法,该方法可以显式考虑预存裂隙网络等岩体细观结构,同时可以模拟新裂隙的产生、扩展和贯通的全过程。在该模型中,岩石基质由随机均布的多边形块体集合表示,相邻块体由共同界面上的弹簧相互连接,岩体的宏观变形由块体的相对位移或裂隙变形来表现。(2)基于离散裂隙网络模型,提出了一种新的双重介质渗流模型。岩石基质的渗透性由沿着块体界面的液体流动来模拟。结合改进刚体弹簧方法,分析了岩石破坏过程中渗透特性变化规律和突变机理。(3)提出了一种基于变分不等式方法的计算模型,用于求解贯通裂隙网络的自由面渗流问题。该方法对具有复杂拓扑关系和边界条件(如排水系统)的裂隙网络均具有很强的适用性,并已推广到三维问题。(4)提出了一种用于模拟密集裂隙岩体水力耦合效应的模型。该模型忽略了岩石基质的变形和渗透特性,渗流和变形都发生在裂隙中。为合理反映裂隙的非线性变形特性,引入了同时考虑非线性法向应力变形关系、剪切滑动和剪胀效应的裂隙本构模型。分析了不同应力条件下水力耦合效应的控制性机理。更多还原

【Abstract】 Estimation of hydro-mechanical coupling effects is very essential in many rock engineering projects, such as geological repository of wastes, high and steep rock slopes and underground hydropower houses. However, due to the presence of discontinuities, both hydraulic and mechanical properties of rock masses are difficult to characterize. In situ experiments are either expensive or impossible, making numerical modeling an inevitable way for characterization of rock mass behaviors.In this thesis, a unified hydro-mechanical coupling model based on the discrete fracture network mode (DFN) and the improved rigid body spring method (RBSM) is proposed for both intact rock and fracture network. Specifically, the main contributions are listed as follows.(1) A meso-scopic model for simulation of rock failure is proposed based on the improved rigid body spring method. In this model, the micro structures of rock mass such as pre-existing fracture network are explicitly considered and the whole process of initiation, propagation and coalescence of new cracks is can be simulated as well. The intact rock is represented by large numbers of uniformly distributed rigid blocks connected with each other by springs. Macro deformation is reflected by the local deformation of common interfaces between blocks.(2) A dual porosity model for seepage flow in rock mass is proposed based on the discrete fracture network model. Combined with the improved rigid body spring method, the permeability variation during rock failure is investigated.(3) A VI formulation for seepage problem with free surface is extended to fracture networks both in2-D and3-D space. This formulation is adapt to solve free surface problems in fracture network even with very complex topology and boundaries such as drainage tunnels.(4) For densely fractured rock mass, the deformability and conductivity of intact rock is neglected. A non-linear fracture constitutive model is introduced to take into account the non-linear normal stress and deformation relationship, tangential shear slip and dilation effects. The controlling mechanisms of hydro-mechanical coupling under different stress conditions are detected.更多还原