DDA Method And Its Application Research In Fractural Rock Engineering

Discontinuous Deformation Analysis (DDA) method, presented after Discrete Element Method (DEM) , is a numerical method can be applied to analysis joint fracture rock and compute dynamic and static behavior of block systems. Exactly, DDA method can be also to analyze force response of continuous material if cohesive strength of virtual joint is big enough and block element is small enough. Most of numerical methods, paralleled with DDA, in geo-mechanics engineering are firstly introduced in this paper, application and important principle of these numerical methods is discussed preliminarily. Basic theory of DDA method and some achievements of research were then presented, which is on basis of understanding core DDA program code. For instance, because of weakness in pre-processer and post processer of DDA, a approach using APDL and C/C++ language is carried out to implement modeling of DDA. Besides, a novel idea is proposed to modeling by using digital image processing (DIP) technology, which can obtain meso-geometrics information about distribution of many minerals in rock sample. In addition, Clustering method is applied to identify structural plane of rock mass, which was accomplished in platform of MATLAB. Finally, Tangjiashan slope is analyzed using DDA method and tunnel roof of sloughing. Detailed work and related conclusion are summarized as follows:(1) On basis of apprehending DDA principle and core algorithm, linear elastic model of plane stress was changed to be that of plane strain, which is used more widespread used in computation.(2) Block elements are formed by joint, fracture plane and/or fault age, which with complicated properties were produced by different condition and different reason. How to identify these structural planes is so important before modeling of DDA. Clustering method is introduced to solve this problem and realized by programming in MATLAB tool.(3) DDA is used to analyze continuous geo-materials deformation. Digital image processing technology is applied to obtain geometric distribution of all kinds of minerals in rock. Image vectorization is also used in this process and a new algorithm is presented in this paper.(4) By computation of free falling body, accuracy of DDA in dynamic force computation is revealed. And then DDA is using to simulate the whole process of slope which is trigged by so many factors such as earthquake, seepage and so on.