Evaluation of gravel drains and compacted sand piles in mitigating liquefaction

Liquefaction induced by earthquakes can cause major destruction to foundations and buildings, mainly as a result of excess pore water pressure generation and softening of the subsoil. Several remediation methods are performed that reduce the excess pore pressure, enhance the shear deformability of the soil, and fortify the soil. Two well-known methods-gravel drains and compacted sand piles-are discussed and compared in this paper. Some precisely prepared 1g shaking table tests are performed regarding these methods. Tests are done with and without the presence of an improvement method, and the accelerations, pore water pressures and settlements are monitored during the tests. The outcomes, judged against each other, reveal that compacted sand piles are more efficient than gravel drains in the case of liquefaction resistance and settlement of the subsoil during the shaking period. Nevertheless, after shaking, the efficiency of the gravel drains is ameliorated by the means of excess pore pressure dissipation.