新型抗滑结构围桩-土的耦合效应分析

Analysis of coupling effect of new surrounding pile-soil anti-slide structure

在引入围桩-土耦合式抗滑结构的基础上建立数值分析模型;通过分析该抗滑结构中围桩-土的应力、应变分布规律,详细探讨围桩-土整个结构的耦合效应特征。进一步开展模型试验,测试并分析围桩前、后土压力和桩身弯矩分布特征,论证了围桩-土耦合式抗滑结构的作用机制。最后,分析了桩后距离、不同深度及不同土体强度参数对土拱效应的影响。得到:(1)围桩与桩内土体耦合呈现出4种应力拱形态:紧邻围桩后为扩肩型拱、围桩间双曲线型拱、围桩间凸向桩外的抛物线型拱、围桩间凸向桩内的抛物线型拱;(2)相邻围桩采用约4倍桩径间距、正六边形布置并顶部用圈梁固结、锚固一定深度可形成一种耦合式抗滑结构。该结论对于该新型抗滑结构的推广应用具有一定的指导意义。

Based on the introduction of surrounding pile-soil coupling anti-slide structure, a numerical analysis model of this new structure is set up. By analyzing the characteristics of stress and strain, soil-arching effect about surrounding pile-soil and coupling effect of the entire structure are discussed. Furthermore, by the model test, soil pressure distribution before and after surrounding pile and sorrounding pile bending moment distribution are tested. The mechanism of surrounding pile-soil coupling effect is proved. Finally, according to relative horizontal displacement of pile-soil coupling, the influences of the distance of behind pile, different depths of plan and different parameters of soil strength and varying effect of soil arching effect are discussed. Then, the main conclusions are drawn as follows： （1） There are four arch forms among the couple structure, such as expanding arch close to the surrounding piles, hyperbola arch between surroundind piles, hyperbola arch protruding outside between surrounding piles and hyperbola arch protruding inside between surroundind piles. （2） Anchoring to a definite depth, it can form a coupling anti-slide structure in the condition of about 4 times diameter space between surrounding piles, horizontal section using hexagon and the top using a ring girder. It can provide a guide to use the new anti-slide structure.