抗滑桩嵌固段设计修正方法研究

STUDY OF IMPROVED DESIGN METHOD OF ANTI-SLIDE PILE SOCKETED SEGMENT

传统的抗滑桩设计方法将抗滑桩简化成一个二维模型,采用计算宽度Bp进行设计,对桩侧摩阻力的简化存在不合理地方,因此对其进行修正方法的研究。在混凝土–岩块胶结面剪切试验的基础上得到胶结面受剪的本构方程,并将其应用到抗滑桩嵌固段的设计中,推导基于K法的抗滑桩嵌固段设计修正方法的计算公式。将修正方法应用到马家沟I号滑坡中,发现修正方法与传统K法相比,计算的桩位移相差较大,内力相差较小。影响因素敏感性分析发现桩位移随残余剪切强度f的增加、临界位移xs的减小而减小,且f对桩位移的影响要大于xs,二者对内力分布的影响不大。位移是控制抗滑桩设计的一个重要指标,因此应考虑桩侧摩阻力的分布,结合胶结面剪切试验进行抗滑桩的设计。

The anti-slide pile is simplified into a two-dimensional model and is designed with the calculation width Bp in the conventional anti-slide pile design method in China.The improved method is studied for the unreasonable simplification of the frictional resistance beside the pile.The shear constitutive equation of the cementation surface is obtained by the concrete-rock cementation surface shear test.The equation is applied to the design of socketed segment of anti-slide pile;and then the design formula based on K method is derived.By using Majiagou #1 landslide as a case to make comparison between the aforementioned improved method and conventional K method,it is found that the difference of pile displacement is great and the difference of internal force is neglectable.Through sensitivity analysis,it is concluded that the pile displacement reduces with the increasing residual shear strength f and the decreasing critical displacement xs.The influence of f on pile displacement is greater than that of xs;both of f and xs have slight effect on internal force distribution.Displacement is an important index in anti-slide pile design;so the anti-slide pile design should take the distribution of frictional resistance beside the pile into account and combine with the cementation surface shear test.