Study On Numerical Manifold Method And Its Application For Continuous-Discontinuous Problem

Nowadays, continuous-discontinuous issue is very common on the analysis of stability and intension of hydraulic structure engineering, such as the dam body cracking, hydraulic fracture, slope sliding of reservoir and so on. Generally speaking, the FEM (Finite Element Method) is often used on continuous problem and the DEM (Distinct Element Method) and DDA (Discontinuous Deformation Analysis) are mainly used on discontinuous problem. However, the NMM (Numerical Manifold Method) which is a new numerical way of two cover systems can combine the FEM and DDA to analyze the continuous-discontinuous issue together. Basing on the theory of continuous-discontinuous numerical manifold method, the paper discusses the main application technique in hydraulic project and introduces some achievement as follows:1) Bases on the numerical manifold theory, the mathematics cover system is discussed which refers to the regular triangular mesh, material division and joint influence; the cover creating system bases on the triangular mathematics mesh is consummated; corresponding calculating program is developed, which can achieve a better adaptation of the complex material division in project.2) The excavation process of underground chamber by changing material mechanics parameter is simulated. The stress condition of gravity dam and underground work and stability on the rock slope are analyzed, in order to prove the correctness of computation program by these calculating examples, In addition, the influence on the computation result of the mesh size of numerical manifold is also analyzed.3) Considered the influence of anti-seepage panel, material partition of masonry and gallery, the stress and deformation of Dongfanghong masonry gravity dam is analyzed by the computation program on Numerical Manifold Theory, the stability of a rock slope in Yuegan expressway (from Shanglin to Puqian) in which considering the influence of rainfall infiltration is also analyzed, and the limit internal friction angle of the rock slope stability is found. The results indicate that the computation program can be used to analyze continuous-discontinuous problems and is acceptable for both small deformation and large deformation of structure.