Research On Theory And Application Of Water-Rock Coupled Processes And The Multi-scale Behavior

With the rock engineering scale larger and larger, and its complexity higher and higher, people's cognition to geological materials is more and more deep. Rock or rock mass is a kind of natural geological body which is rich in weak structure planes and fractures. The differences or the randomicity of its diagenesis and diagenetic environment lead to the discontinuous, inhomogeneous, anisotropic and non-elastic (DIANE) characters of rock masses in their macrostructures and microstructures. In addition, combined with different ground stress environment and its change, abundant rock mass structure planes with different directions are formed, which affects the deformation and seepage process and the strength of rock and rock mass. Multiscale properties of rock or rock mass are studied in this thesis. By extracting the multiscale information and combining them with numerical methods, the mechanical and hydraulic and their coupling properties are discussed from rock to engineering rock mass. The main purpose is to provide a more effective and finer method for behavior analysis and predicting of real engineering.The concept of digital rock or rock mass models is put forward firstly. The special rock or rock mass scale is divided to be meso-scale, lab-scale, engineering-scale and regional scale, and the modelling methods, including the meso-scale digital rock modeling based on the digital image process, the lab-scale digital rock modeling by random sub-structure simulation method and the large scale digital rock mass modeling by random fracture networks simulation method are given. Many inhomogeneous digital rock or rock mass models containing different sub-structures are modeling according to the various shape of natural engineering rock or rock mass. In addition, the concept of virtual rock engineering is presented, and the theory of rock mass virtual reality and its application are introduced.On the basis that have been mentioned, FEM-based computer codes, GeoCAAS (Geo Computer Aided Analysis System), are developed to study the mechanics, hydraulics, and the coupled process between them with the various digital rock or rock mass models. The relationship between mechanics and hydraulics properties of rock or rock mass and the sub-structures is discussed.The homogenization method is utilized to deduce the control equations of rock-water coupled process from meso-scale to lab-scale. The syncretization and relationship of the information between these two scales are revealed.The ultimate water pressure in rocks with circular and elliptic holes is deduced, and water pressure sensitivity characterizing coefficient is defined to discuss the influence of holes'scale on the water-rock coupled process. The multi-scale hierarchy finite element method (MsHFEM) is provided for multiscale probloms in rock engineering, and the multi-scale finite element method (MsFEM) and MsHFEM are applied to study the seepage process in heterogeneous rock mass.