Abstract

In order to simulate the behavior of composite structures consisting of discontinuous blocks on the saturated ground, a soil-water coupled code based on NMM-DDA (coupled Numerical Manifold Method and Discontinuous Deformation Analysis) for saturated ground was newly developed. The code consists of three governing equations, the equation of motion for the DDA part, the equilibrium equation and the continuity equation for the NMM part. In the formulation, the first and the second equations were combined using the contact treatment with the penalty method similarly to the original NMM-DDA. Then, the equilibrium equation and the continuity equation for the NMM region was coupled with the effective stress concept based on u-p formulation. This coupling formulation enables the stability analysis of masonry structure on the saturated ground. As a verification of newly developed simulation code, one-dimensional consolidation analysis was carried out. The simulation results showed good agreement with the analytical solution of Terzaghi’s consolidation equation, and the validity of the new code was confirmed.

1. INTRODUCTION

There are many geotechnical engineering problems significantly affected by geometrical discontinuity, although the soil mechanics is usually discussed based on the continuum mechanics. A typical example is the stability problem of masonry or concrete block structures constructed on a soil foundation. Fig. 1 is a historic masonry building in Cambodia which foundation ground showed uneven settlement due to the self-weight of the structure [1]. The building was inclined because of the settlement, and some joint openings appeared on the wall. The mechanical behavior of this kind of structure is governed by mutual interaction between discontinuous structural members, interaction on the ground-structure interface, and the deformation of the ground. Additionally, when a structure was constructed on a ground which may shows consolidation phenomenon, generation and dissipation of excess pore water pressure will have much impact on the long-term deterioration process of the structure. Since it is difficult to solve such a complicated problem theoretically, development of numerical methods which can consider above factors is demanded for the stability evaluation. In this paper, as a method which satisfy the requirements mentioned above, a soil-water coupled analysis code based on NMM-DDA [2], one of the discontinuum based numerical methods, was newly developed.

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