轴-横向荷载作用下超长桩数值模拟

Numerical investigation on interaction of axial and lateral response for super-long pile

轴-横向荷载作用下的桩土相互作用研究主要集中在单层土中的中短桩,工程设计将水平、竖向荷载作用分开单独考虑.本文对成层地基中超长桩在轴-横向耦合荷载作用下展开数值模拟研究和试验对比,结果表明,轴?横向荷载作用下的超长桩桩-土相互作用主要集中在土体浅部区域,竖向荷载作用使得桩身弯矩、水平位移减小,从而提高了桩基础水平承载力;对于软粘土,水平荷载能在一定程度上提高超长桩的竖向承载力.桩侧土与桩端土的变形模量比也是影响超长桩承载性能的重要因素,两者比值越大,侧摩阻力占总荷载比例越低.本文建立的超长桩数值模型计算结果与实测数据吻合较好.

Research on the soil-pile interaction under vertical and lateral loads is currently focused on the short or middle-long piles in homogeneous soil; the current practice for design of piles is to consider the vertical and lateral loads independent of each other. The principal objective of this paper is the development and validation of a series of models for soil-pile interaction under simultaneously applied lateral and vertical loads. The results show that the presence of vertical loads decreases the lateral displacements and bending moments of the super-long pile; for soft clay, the action of lateral loads increases the vertical bearing capacity of super-long pile. The Young＇s modulus rate between the soil of pile bottom and surrounding area of pile is a sensitive factor for the variation of bearing capacity of super-long pile, and as the rate increases, the vertical bearing capacity decreases significantly. Finally, two three-dimensional models are developed and the computing results by these two models are compared with the test curves. The calculated results agree well with the filed test data.