RIASSUNTO
ABSTRACT
A new development for the theory proposed by Seed and Booker (1977), with experimental works by Lee and Albaisa (1974), can be used to illustrate the settlement ratio versus the excess pore water pressure ratio for various time factors. These figures can be used to illustrate when calculating settlements. In order to investigate the best layout for gravel drain, a series of shake table tests was performed with the following dispositions: a gravel wall, square gravel piles and diamond gravel piles. The experimental parameters included different gravel wall thicknesses and gravel pile diameters. For a certain amount of time, the ground-surface settlement for gravel wall and gravel piles were mentioned; in addition, topographic chart software was used to display settlement variations. All studied dispositions efficiently prevented settlements. It was also found that the area ratio (area of gravel/area of whole system) of the gravel piles or gravel wall could reduce excess pore water pressure after a series of shaking table. Finally, the gravel wall outperformed the diamond and square pile in terms of settlement reduction.
INTRODUCTION
Liquefaction typically results in a lot of serious damages during or after an earthquake, and some feasible mitigation techniques, including a gravel drain or stone column, have been suggested. Lu and Su (2002) collected many case histories of stone columns construction on difficult ground in Taiwan to illustrate this phenomenon. The results show that the success of a stone column is significantly influenced by the construction sequences. However, many papers discuss cases studies and numerical solutions; the contribution of the construction sequence has not been studied as thoroughly. To understand the availability of a wall or pile disposition, a series of small-scale shaking table test was performed for different distribution, thicknesses and soil densities.