帽型钢板桩挡墙土压力分布离心模型试验

采用离心模型试验模拟了帽型钢板桩挡墙支护的基坑开挖过程,研究了钢板桩挡墙两侧土压力分布的变化规律,并与等效截面刚度的平板挡墙支护开挖试验进行了对比,分析了钢板桩挡墙迎土面的起伏几何形状对土压力分布的影响.试验结果表明,钢板桩挡墙的截面形状影响其后土压力分布,相同高程处钢板桩挡墙凹凸部分的土压力不相等,大小关系与其位移模式有关.当墙体远离土体运动时,迎土面凹处土压力大于凸处,当墙体靠近土体运动时,凹处土压力则小于凸处.随着基坑开挖深度的增加,墙体变形模式产生变化,导致钢板桩挡墙两侧土压力的时空分布在不同埋深处也有所区别.

Earth Pressure Against a Hat-shaped Sheet Pile Wall Revealed by Centrifuge Modeling

A pit supported with a wall formed by hat shaped sheet pilings was modeled in centrifuge apparatus to investigate the earth pressure against the wall during excavation. A parallel test using a planar wall with equivalent bending stiffness was also conducted to demonstrate the effect of the extruding surface of the sheet pile wall on the earth pressure distribution. The results show that the distribution of earth pressure on the sheet pile wall is influenced by the cross sectional shape of the wall. The earth pressure against the extruding and denting portions of the wall differs at the same elevation, and the difference is affected by the displacement mode of the wall. The earth pressure against the denting portions is larger than that of the extruding portions when the wall moves away from the soil; it becomes opposite when the wall moves towards the soil. The displacement mode of the wall changes during excavation, and this further complicates the spatial distribution of earth pressure which varies with the elevation.