考虑土拱效应的悬臂式抗滑桩最大桩间距确定

Maximum cantilever anti-slide piles spacing determination with consideration of soil arching effect

合理桩间距的确定是抗滑桩设计的重要内容之一。认为抗滑桩的抗滑能力主要来自桩身迎荷面的阻滑能力和桩侧的阻滑能力这两个方面。在假定抗滑桩这两方面的阻滑能力均充分发挥的基础上,从桩侧摩阻力与桩后土拱极限剪切作用厚度范围内的摩阻力与拱后滑坡推力之间的静力平衡条件出发,基于Mohr-Coulomb强度准则,简化摩阻力的分布形式,建立悬臂式抗滑桩桩间距的计算公式。在此基础上,进一步研究了滑坡体的黏聚力、滑坡推力及抗滑桩的截面尺寸等因素对桩间距的影响。参数分析结果表明:桩侧阻滑能力在整个抗滑桩的抗滑能力中占有重要比例,且主要受桩侧面宽度控制;滑坡土体的黏聚力、内摩擦角,桩截面宽度等因素对抗滑桩最大桩间距具有较大程度影响。

Determining reasonable spacing between two adjacent piles is one of the important contents in the anti-slide pile design. In this study, the anti-sliding ability of pile is mainly combined with two parts: the anti-sliding ability from the pile back face and ability from the pile side. Assuming the anti-sliding ability of the pile is putting into full play, a new spacing calculation formula between two adjacent anti-slide piles has been presented based on Mohr-Coulomb strength criterion. The landslide thrust of the present method is balanced by the pile-soil shear friction on pile side surface, and the soil-soil shear friction within the ultimate shearing thickness of soil arching on the pile back face. Both the pile-soil and the soil-soil shear frictions are simply assumed to have linear distributions along its shearing thickness. Based on the proposed method, a parameter study has been conducted to investigate the influence of multiply factors, such as cohesion of landslide soil, slide force and cross section size of plie on the pile spacing. The results show that the anti-sliding ability from the pile side, which mainly controlled by the pile side width, plays an important proportion in the whole anti-sliding ability of the pile. Moreover, the maximum spacing between adjacent anti-slide piles is significantly influenced by the cohesion and internal friction angle of landslide soil and the width of piles.