Numerical Simulation Of Jointed Rock Mass By Block Element Method And Its Application On Engineering

In the paper, Theory and improvement of block element method (BEM) are introduced in detail. It can analyze elastic and plastic strain and thermal stress of block element. Some mechanical models, visco-elastic-plastic rheological model, coupling analytical model of fissure seepage and rock deformation, mixed numerical model of finite element method (FEM) with block element method, practical model of anchored rock mass, are established. These models are applied to study the deformation and stability of rock engineering project as underground powerhouse, gravity dam and its foundation, arch dam and its abutment, rock slope and so on. The new main ideas and content are listed as follow.To modify the theory of available block element method. Now it not only considers the rigid body displacement of block, but also regards its constant strain as unknown variable. Therefore the calculation can include block elastic-plastic deformation. Its numerical precision is increased too. The result accords with the practical situation better.A new mixed calculation model of FEM and BEM is presented. It can shares both merit of FEM and BEM. At last, the computer program established by author is applied to discuss surrounding rock stress and deformation of a underground powerhouse.To establish the theory to calculate temperature field and thermal stress by block element method. By the help of it, it is conveniently to analyze the stress and deformation of hydraulic structure like dams. Corresponding computer program is successfully utilized to research safety and stability of XILUO concrete arch dam.To introduce a rheological mode of elastic-viscoelastic-viscoplasticity into contact element between blocks. So, the block element method can research the rheological deformation and stability of fractured rock, and reveal the deformable characteristic depended on time. Its analytical procedure and formulas are deduced, and compiled into computer program. The program is successfully applied to a rock slope project. The results show that the method is feasible.To simulate the reinforcement effect of concrete overlay and anchored rod to fractured rock mass. In the paper, anchor rod is simplified as a special component through block elements. Its anti-tension and anti-shear stiffness is considered, and is integrated to whole stiffness of structure. Concrete overlay is modeled as shell element, and its rigidity is equivalent directly to whole structure without dividing itinto block element alone. When using variation principle to deduce the equilibrium equation of block element, the potential energy of anchored rod and concrete overlay are taken into account in whole structure. Its stiffness is added to integer stiffness matrix. So, the reinforcement effect is directly and objectively affiliated. At last, corresponding theoretical formulas and computer program is presented, and applied on the adjacent rock reinforced simulative analysis in a underground powerhouse.To establish coupling analytical model of fissure seepage and rock deformation. The safety of underground engineering is affected seriously by underground water. So, it is important to study the coupling action both of them. With BEM, it is advantageous to establish the coupling theory of rock deformation and fissure seepage. In the paper, its theoretical formulas and computer program are worked out, and used to study interaction between fissure seepage and rock deformation of a gravity dam foundationTo discuss the application of numerical ultimate load analysis method (by block element method) on the engineering stability and degree of safety, such as the stability against deep sliding of side slope and gravity dam, adjacent rock stability in the underground building and etc.