A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 2002

The numerical modeling of the full scale test embankment reinforced with steel grid reinforcement and hexagonal wire mesh have been analyzed by finite element and finite difference methods under two-dimensional (2D) as well as threedimensional (3D) conditions. The 2D numerical simulations, using finite element program, PLAXIS, and finite difference program, FLAC30 can be adopted to investigate the overall behavior of steel grid reinforced embankment on soft soil foundation and agreed well with the predicted results proposed by Chai (1992). The 2D numerical simulations of hexagonal wire mesh reinforced embankment by using finite element program, PLAXIS, and finite difference program, FLAC30 using 25 times of vertical laboratory permeability 25 (kv) overestimated the measured settlement data. Furthermore, the predicted results from 3D analysis using 25 times of vertical laboratory permeability 25 (kv) of hexagonal wire mesh reinforced · embankment are lower than the 2D analysis. The predicted maximum pore pressures under 2D condition are higher than those under 3D condition. For the analysis of hexagonal wire mesh reinforced wall, the 3D finite difference simulation using 5 times of vertical laboratory permeability (5kv) can reasonably capture its behavior on soft foundation. In comparison with the field measurements, the predicted results from 3D analysis reasonably agreed with measured data. Thus, the finite size boundary and the selected permeability influenced the behavior of the reinforced embankment constructed on soft ground foundation. The simulated maximum tension lines in the reinforcements tend to follow the coherent gravity failure plane. The maximum tension at the bottom of the reinforced embankment occurred near midpoint portion away from the facing due to the settlement of the soft soil foundation. The tensions in the reinforcement increase from Ka-line to K0-line with increasing vertical settlements and the lateral displacements of the wall. Finally, The factors affecting on the numerical simulation were the stages of the construction, the boundary conditions in the field, the variation of soil permeability of the soft soil foundation, and the selection of appropriate model as well as the properties of the interface between the backfill soil and the reinforcement material corresponding to their interaction mechanism.