土工袋垫层抗液化性能振动台试验研究

Shaking table tests on liquefaction resistance performance of soilbag-stacked cushion

土工袋能够有效地约束袋内土体,具有良好的滤水保土作用,可以用于地基抗液化,但土工袋抗液化性能尚未有系统及深入的研究。开展了一系列小振动台试验,验证土工袋垫层的抗液化效果,研究了振动加速度、土工袋层数和排列方式对抗液化性能的影响。结果表明:土工袋具有良好的抗液化效果,袋内土体的超静孔压比小于同深度处周围的土体;土工袋垫层的排水性能是在土工袋本身具有良好透水性的基础上,孔隙水会沿着土工袋与土体的界面以及袋间的空隙排出;相较于不透水刚性垫层,振动过程中土工袋垫层表面基本保持水平,发挥出较好的变形协调性;土工袋层数增加及交错式排列对抗液化效果有利。

Apart from the effective restraint soils, soilbags have also a function of water filtration and soil conservation, so they can be used to resist foundation soil liquefaction. However, seldom studies have been made on the liquefaction resistance performance of soilbags. A series of shaking table tests was carried out on soilbags-stacked cushion to verify its liquefaction resistance performance and investigate the influence of the vibration acceleration, the layers and arrangements of soilbags on liquefaction resistance. The results show that soilbags have good liquefaction resistance effect, and the excess pore pressure ratio of soil in bags is less than that of the surrounding soil at the same depth. The drainage performance of soilbags is contributed to its good permeability, and the discharge of pore water along the interface between soilbags and foundation soil as well as the gaps among soilbags. Compared with the rigid impervious cushion, the surface of soilbag cushion basically keeps level during the process of vibration, showing better deformation coordination performance. The increase of soilbag layers and the staggered arrangement of soilbags are beneficial to anti-liquefaction.