全埋式抗滑桩倾覆破坏的室内模型试验研究

基于室内推桩模型试验研究全埋式抗滑桩的倾覆破坏及受力变形特征:在满足各试验相似关系的前提下,建立室内模型试验池,观察模型桩从受荷到倾覆破坏的全过程。布设土压力盒、钢筋应变片、混凝土应变片及百分表,采用多通道动态测试系统,对桩身应变、钢筋应变、桩顶位移与土压力进行全方位的动态监测,分析模型桩的受力特性。研究结果表明,在滑坡推力作用下,桩顶水平位移与荷载之间大致呈现三折线关系,而且在锚固深度不够的情况下,桩的破坏形式为整体的刚性转动(倾覆破坏)。对土压力监测结果以及反推的桩身弯矩表明,桩身土压力分布曲线表现为上下小、中间大的近似抛物线分布,桩身最大土压力出现在桩中部;各级荷载作用下,桩身最大弯矩值出现在滑面处,桩顶及桩底弯矩值较小。

Model experimental study of toppling failure of fully-embedded anti-sliding pile

Based on the indoor-push-pile model experiments, the toppling failure mode and stress deformation characteristics of the fully-embedded anti-sliding pile are studied. Under the premise of the test similarly relation, the indoor model experiment-pool is established; and from loading to the toppling destruction of the whole process, the deformations of model pile are observed. Arranging earth pressure cells, steel strain gauges, concrete strain gauges, and dial indicators, and using a multi-channel dynamic measuring system to monitor pile strain, the steel strain, the displacement of pile top and the earth pressure, the mechanical characteristics of the model pile is analyzed. It is shown that, the relationship of load and lateral displacement of the pile top could be divided into 3 stages. When the anchorage depth is not enough to the monitoring results, the destruction form of the pile performs as a rigid rotation (toppling failure). The soil pressure of the pile is approximately parabolic. Maximum soil pressure is near the middle of the pile. The moment of the pile is larger around the sliding surface and smaller at the top and bottom of the pile.