基于模型试验的桩间距对组合式钢管抗滑桩抗滑效果的影响分析

通过大型物理模型试验分别对3种不同桩间距组合式钢管抗滑桩治理滑坡的力学效应进行研究，对比分析桩顶位移、剪出口位移、桩身弯矩随荷载的变化规律和桩体、滑坡的破坏情况，讨论桩间距对组合式钢管抗滑桩抗滑效果的影响。试验结果表明，当桩间距由18.7 cm依次增大至23.5、28.0 cm，即由3.9d增大至4.9d、5.8d（d为小直径圆形钢管的外径），同等荷载作用时桩顶水平位移、剪出口水平位移、桩身弯矩逐渐增大，但桩间距由3.9d增大至4.9d时，位移与弯矩的增大幅度远大于桩间距由4.9d增大至5.8d。建议在组合式钢管抗滑桩设计中，若滑坡推力较小，可适当增大桩间距至5.8d甚至更大；若滑坡推力较大，应适当减小桩间距至3.9d甚至更小。无论滑坡推力较大或者较小，桩间距为4.9d的组合式钢管抗滑桩治理滑坡的性价比均较低。

Analysis of anti-sliding mechanism of steel tube piles with different spacings based on model test

By using the large physical model test, this paper investigated on the mechanism of the component steel tube anti-sliding piles distributed in different spacings. The authors have compared factors affecting of the spacing on the mechanism of the anti-sliding among the pile top’s distance, the cut-export distance, the bending moment distribution under changing loads and the destruction situation. The experiment results show that when the spacing is increased from 18.7 cm (3.9 times of d the pile external diameter) to 23.5 cm (4.9d) and 28 cm (5.8d), the distance of pile top and cut-export increases gradually. Besides, the bending moment of the pile also increases gradually. But when the spacing is increased from 3.9d to 4.9d, the increase range of the distance and the bending moment are greater than that when the spacing is increased from 4.9d to 5.8d. Thus, during the design of the component steel tube anti-sliding pile, it is better to increase the spacing to 5.8d or more when the landslide thrust is small and decreases the spacing to 3.9d or less when the landslide thrust is large. Whether the landslide thrust is large or small, the component steel tube anti-sliding pile has a low-cost performance to treat landslide when the spacing is 4.9d.