考虑m弱化效应的水平循环受荷桩分析

Analysis of lateral cyclic loaded pile considering weakening effect of m value

现行规范采用m法分析水平受荷桩的内力和变位时,将地基系数的比例系数m视为定值。承受水平循环荷载作用的桩,当桩周土体发生较大位移时,其m随桩在地面处位移增大和加载次数增加均呈减小趋势。基于现场原型试验结果,分别建立m随桩在地面处位移y0及循环加载次数T的幂函数关系式;考虑m的上述弱化效应,构建水平循环受荷桩桩身挠曲微分方程,编制其内力与变位有限差分求解程序,通过与现场试验对比分析,验证该计算方法能较好地适用于深厚软土地区在地面处水平位移大于4 mm的水平循环受荷桩的内力与变位计算。

The ratio coefficient m of the ground coefficient was considered as a constant,when m method was used to analyze the internal force and displacement of lateral loaded pile in current specifications.m of the soil around the lateral cyclic loaded pile decreases with the increase of the displacement of pile top and the loading cycles times.Two power function relationships were established separately based on the field prototype test results.One was that m decreased with the increase of the displacement of pile top,and the other was that m decreased with the increase of the loading cycles numbers.Based on the weakening effect of m,the differential equation of pile deflection of lateral cyclic loaded pile was established,and then the finite difference program to calculate internal force and displacement was compiled.After comparing the field test results with those from calculation,it is proved that the proposed method is proved can be applied well in the calculation of lateral cyclic loaded pile,of which the horizontal displacement at the ground surface is larger than 4 mm in deep soft soil area.