MODELLING THE INFLUENCE OF ROCK ANISOTROPY ON THE STABILITY OF UNDERGROUND EXCAVATIONS
When modelling the potential failure of underground excavations, it is necessary to include the DIANE nature of the real rock mass, i.e. the discontinuous, inhomogeneous, anisotropic and non-elastic characteristics. Many studies have been conducted to establish the influence of fractures and different failure criteria have been used. Not so much work has been undertaken to study the influence of the combined effect of inhomogeneity and anisotropy when there are different excavation shapes. In this paper, the influence of rock anisotropy and excavation shape is studied using the Rock Failure Analysis code, RFPA2D. The inhomogeneous characteristics of rock at the mesoscopic level are included by assuming that the material properties of the constituent elements conform to a Weibull distribution; the anisotropy is incorporated as a transversely isotropic medium; the non-elastic characteristic is simulated via an elastic damage-based constitutive law. A finite element program is employed as the basic stress analysis tool. Additionally, pre-existing fractures can be included. In this way, the DIANE nature of real rocks is fully simulated in the modelling. The deformation and failure process of anisotropic rock around excavations of different shapes (four geometries) on stability is analyzed. The loading mode with a slight confining stress is shown. Four excavation shapes with similar cross-sectional areas are simulated and discussed. The progressive damage mechanism and any self-stabilization are evident. It is found that tension fractures are the dominant failure mechanism in these modes as failure processes. The figures clearly illustrate that the failure, both initiation and propagation, occurs as a combination of the stress concentrations and the weakness planes introduced via the transverse anisotropy -which could represent either foliation or a ubiquitous joint set. Thus, design analyses for rock engineering facilities should be based on modelling which includes all the DIANE characteristics, as illustrated here.
Shuhong Wang John A Hudson Chun-an Tang
School of Resource and Civil Engineering, Northeastern University, Shenyang 110004, P.R.China Depart Department Earth Science and Engineering, Imperial College of Science,Technology and Medicine, Londo Department of Engineering Mechanics, Dalian University of Technology, Dalian 116024, P.R.China Schoo
国际会议
南京
英文
710-717
2006-05-22（万方平台首次上网日期，不代表论文的发表时间）