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

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

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。

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（4.9 d） and 28 cm（5.8 d）, 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 3.9 d to 4.9 d, the increase range of the distance and the bending moment are greater than that when the spacing is increased from 4.9 d to 5.8 d. Thus, during the design of the component steel tube anti-sliding pile, it is better to increase the spacing to 5.8 d or more when the landslide thrust is small and decreases the spacing to 3.9 d 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 4.9 d.