考虑桩土相对滑移的单桩和群桩的非线性分析

Non-linear analysis of behavior of axially loaded pile groups considering limited soil resistance

建立了考虑桩土界面可以滑移、土体存在极限阻力的单桩分析模型,采用位移协调法分析了单桩的荷载传递特性.在此基础上,研究了桩顶荷载水平对两桩相互作用系数的影响,建立了考虑桩顶荷载水平的相互作用系数计算公式.并将上述方法应用于群桩的分析,获得了群桩的荷载沉降特性.本文提出的单桩和群桩弹塑性分析方法克服了目前应用较多的弹性理论法夸大桩土相互作用的缺点.单桩和群桩荷载沉降曲线的分析结果和实测数据吻合,说明了该方法的合理性.

The application of available numerical methods to realistic pile group problems is not recommended because they are mainly restricted to linear elastic analyses and relatively small groups of piles. Consideration of a large number of piles necessarily involves the global dimension of the group. The nonlinear behavior of an axially loaded single pile was studied by considering the limiting shear stress in the slip zone between pile and soil. Then it was extended to obtain the interaction factor of two piles with the increase of pile reaction. The approximate approach with the concept of interaction factor of two piles was employed to study the behavior of a pile group. Comparisons of the results with some available solutions were employed to assess the accuracy of the present approach. The general good agreement with the results of field tests and alternative numerical analyses gives confidence to the applicability of the method in practical problems, and offers the prospect of tangible improvements in design procedures and worthwhile savings in construction cost.