近年来,随着现代城市工程建设规模的不断扩大,由工程弃土引起的渣土边坡稳定性日益引起各界的高度关注,但目前对多层渣土边坡的桩间距研究较少且大多数未考虑地下水对桩间距的影响。鉴于此,基于统一强度理论开展了考虑地下水与不考虑地下水2种条件下多层渣土边坡模型最大桩间距研究。首先采用GEO-STUDIO搜索出2种渣土边坡模型的潜在滑动面,查明了抗滑桩桩后推力分布特征,建立了考虑土拱受力形式的桩间土拱模型;然后根据基于统一强度理论的强度条件和平衡条件,推导出了各层滑体的最大桩间距计算公式;最后研究了多层边坡中各滑体相互作用形式,用于确定渣土边坡的最大桩间距。2种多层渣土边坡模型的计算结果显示:考虑地下水存在情况下的边坡的滑体体积和剩余推力更大,而稳定性系数和最大桩间距更小。深圳某渣土边坡实例的计算结果表明,本文所提出的最大桩间距研究方法对实际工程中多层渣土边坡中最大桩间距的确定具有一定的借鉴意义。

Despite that the stability of landfill slope has been receiving increasing concern from all fields, the spacing of stabilizing piles in the landfill slope has not been widely researched, not to mention the influence of groundwater on pile spacing. In view of this, we investigated the maximum spacing of stabilizing piles in landfill slope in two conditions (in the presence and in the absence of groundwater) in the light of the unified strength theory. Firstly, we employed GEO-STUDIO to searching for the potential sliding surfaces of landfill slope in the aforementioned two conditions, acquired the thrust distribution behind the stabilizing piles, and built a soil arch model between piles. Subsequently, we deduced the calculation formula of maximum spacing of piles based on the strength condition and equilibrium condition in the unified strength theory. Finally, we determined the maximum spacing of piles on the basis of studying the interaction among sliding bodies in the multilayer landfill slope. The calculation results illustrated that in the presence of groundwater, the volume of the sliding body and the residual thrust of the slope are larger than those in the absence of groundwater; but the stability coefficient and the maximum pile spacing are smaller. In addition, we applied the calculation formula proposed in this paper to a landfill slope in Shenzhen, and results demonstrated that the formula could serve as reference for determining the maximum pile spacing in multilayer landfill slope.