合理间距条件悬臂式抗滑桩三维土拱效应试验研究

在人工开挖的斜坡上施工满足合理桩间距的两根悬臂式抗滑桩,通过对模型槽内填土的顶面进行堆载,研究了桩前施工挡土板时挡土板水平变形和桩–板土压力比的变化规律。待位移传感器和土压力计读数稳定后,采用自上而下摘板的措施模拟桩前土开挖的施工过程。通过分析不同高度上测点x方向土压力的分布规律,探讨了桩间土沿高度方向直接土拱与摩擦土拱的作用程度及作用范围。摘板过程结束后,对桩间土的局部滑塌面进行测量,通过与三维土拱效应的作用范围进行比较,证实了合理桩间距条件下桩间土产生局部滑塌的范围总是处于直接土拱的拱圈内侧区域。采用自制的简易静力贯入设备对拱脚剪切线附近的原状土进行测定,基于实测锤尖贯入曲线,分析了桩间不同高度上拱脚的极限剪切作用厚度。

Experimental investigation on three-dimensional soil arching effect between adjacent cantilever anti-slide piles with rational spacing

In manual excavation of slopes two cantilever anti-slide piles are constructed in rational spacing.Through stacking boulder strips on the top of fill heaped on the back of piles,horizontal deformation of breast boards and soil pressure ratio of piles to breast board are studied when the breast boards are constructed in front of piles.In order to simulate the excavation process of soil in front of piles,the boards are taken down from top to bottom after the readings of displacement sensors and soil pressure cells are stable.The action extents and ranges of direct and friction soil arches are discussed according to the analysis on regularities of x-direction soil pressure distribution along different levels.The partial slump surface of soil between piles is measured after the breast boards are taken down.The results which contrast the partial slump surface of soil between piles and influence circle of three-dimensional soil arching effect testify that partial slump surface is usually located at the inner of soil arching area between piles with rational spacing.Finally,a simple static penetration device is made for evaluating the solidity of undisturbed soil on shear failure line of arch spring,and the ultimate thicknesses of shear action are analyzed at different heights based on the measured penetration curves.