预应力锚索修复变形抗滑桩模型试验与数值模拟分析

Numerical analysis and model test of deformed anti-sliding pile repaired by anchor cable

为了验证锚索预应力修复加固变形抗滑桩机制,在大型野外模型试验的基础上,对模型试验进行了数值分析。数值分析结果表明,数值模拟与模型试验结果较为吻合,预应力锚索的施加可有效控制变形抗滑桩桩顶位移,降低桩身弯矩,提高抗滑桩承载能力,从而达到加固变形抗滑桩的目的,验证了锚索预应力修复加固变形抗滑桩机制。讨论结果表明:采用锚索预应力修复加固变形抗滑桩存在预应力上限值,此上限值随滑坡推力的增加三次抛物线降低,随桩顶位移的增大负指数降低,随距桩顶位置增加近似线性降低;在滑坡推力作用下,桩后土压力为正三角形分布,在预应力锚索修复荷载作用下,呈现为折线型分布。研究成果对于变形抗滑桩的修复加固工程设计具有指导意义。

Numerical analysis of model tests are conducted to verify the repair and reinforcement mechanism of deformed anti-sliding pile repaired by anchor cable,based on the large site model tests.The numerical analysis results indicate that,the results of numerical simulation agree well with the model test,and pre-stressed anchor cable acted on the deformed anti-sliding pile can effectively control the displacement of the pile top,reduce the pile bending moment,and improve the bearing capacity of the anti-sliding pile,thereby achieving the purpose of strengthening the deformed anti-sliding pile.It is discussed that,there is an upper limit value of prestress by using anchor cable prestressing to repair and reinforce the deformed anti-sliding pile.This upper limit value decreases as three parabolas with the increase of landslide thrust,and negative exponential with the increase of displacement of pile top,and approximately linearly with the increase of distance between the position with the pile top.Under the action of landslide thrust,the soil pressure behind the pile is distributed in an equilateral triangle,while under the action of the repair load of prestressed anchor cable,it is presented in a folded line distribution.The research results guide the significance of engineering design of restoration and reinforcement of deformed anti-sliding piles.