Numerical Analysis for Granular Ground Using the Advanced DEM

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The main purposes of this investigation are to demonstrate that DEM is a helpful method in examining geotechnical problems, moreover, to clear the behavior of ground as granular material.First, for the attainment of these purposes, elasto-plastic type DEM was developed, which expressed plastic energy dissipations caused by elements contact, and coupled with solid skeletons and pore water pressures and flow. However, it had be come clear that analytical results of the modified DEM were too much influenced by the values of plastic constants. So large and irreversible deformations of solid skeletons with random generations of pore were modeled by the reduction of element stiffness. Consolidation and liquefaction problems were analyzed with regular arrangements of uniform circle elements, and e-log p curves and changes of pore water pressure during cyclic loading were illustrated. Through these analyses, The applicability of DEM to sandy soil ground was certified.Second, fractal dimensiona … More l analysis was introduced, which was intended to evaluate the roughness of the jointing surfaces and to determine the analytical conditions of DEM in applying to discontinuous rock mass. Analyses for rock slopes composed of hundreds of uniform rectangular blocks were carried out where discontinuities were simplified as following two patterns ; 'intermittent' and 'cross-continuous'. The comparison between pseudo-static inclination analysis and dynamic shaking analysis gave effective data in discussing the stability of rock slopes. After these fundamental colculations, DEM analyses were performed on a rock slope failure which happened along Echizen coast road. Some Probable scenarios of the slope failure were obtained, which may give useful information to judge the true cause and failure behavior by comparison with field observations.All the results obtained from this study fulfilled the requirements as mentioned above. After the accomplishment of the main purposes, a new numerical method named FLEM was expressed utilizing the basic theory of DEM. FLEM is expected to be a powerful method in analyzing large deformation and flow problems. Less