嵌岩桩抗滑特性的物理模型试验研究

Physical model test research on anti-sliding characteristics of rock-socketed pile

进行嵌岩桩与滑坡体相互作用的框架式滑坡物理模型试验,根据微型土压力盒和电阻应变计的监测数据,分别研究滑坡推力作用下模型桩的受力特征、桩身弯矩分布规律及模型变形破坏模式。试验结果表明,嵌岩桩加固后的滑坡,桩后推力随深度的增加呈抛物线型分布形式,合力作用点约在滑动面以上模型桩自由段的1/2处;嵌岩模型桩有明显的抗滑特性,承担了大部分桩后推力,传递至桩前土压力值较小且稳定;模型桩的桩身弯矩分布形式不同于普通抗滑桩弯矩分布形式,自由段埋深0~15 cm范围内为主要弯矩承受区域,最大弯矩截面位于滑面上模型桩自由段1/3处,滑动面处桩身弯矩绝对值较小;滑坡模型在沿滑面推力加载作用下发生桩后滑体越桩滑动破坏。该试验成果为嵌岩桩的抗滑特性研究提供了科学依据,可为该类型抗滑桩设计提供一定的指导性建议。

This paper presents the study of interaction between the bottom built-in piles and landslide mass through the landslide physical model test. Based on the monitoring data from micro soil pressure cells and resistance strain gauges, mechanical characteristics of model pile, bending moment distribution rule of pile body and model deformation failure mode are studied. The test results show that the trust behind the pile is a parabolic distribution and the resultant force point is in half of free part above the sliding surface. Since the built-in piles take the most part of pushing force, the soil resistance in front of it is more stable and smaller. Meanwhile, the bending moment distribution form of pile body is different from any ordinary anti-sliding pile. The range from 0 to 15 cm depth is the main bearing area of bending moment and the maximum moment lays in one third of free part above the sliding surface. The bending moment near the sliding surface is relatively small. At last, the sliding mass flows above the model piles under the pushing force when the test comes to the end. The results of indoor model test show some regulations of the anti-sliding characteristics and provide scientific guidance for the design of rock-socketed piles.