拉压模量不同理论在桩筏基础分析中的应用

Analysis on different modulus in tension and compression for piled rafts

将拉压模量不同的概念引入到桩筏基础柔度矩阵中,建立了桩筏基础简化分析模型,板单元采用基于广义协调元思想的厚薄板通用单元,解决了剪切闭锁现象;桩周土体的作用采用荷载传递法,能够考虑由于沉桩、土固结引起的有效应力变化以及桩的加载过程对荷载传递函数的影响。讨论了地基土拉压模量比对桩筏基础沉降、地基土分担比和筏板内力的影响规律。提出现有工程设计中,对于多层、小高层建筑筏板较薄的情况,不考虑拉压模量不同,会低估筏板的实际弯矩,存在安全隐患。

Different modulus in tension and compression theory was embedded in pile foundation displacement field. A simple method was proposed for piled rafts. For solution of shear locking, the thin-thick plate element based on generalized confirming for raft was used. The soil behavior of response of individual piles nonlinearity was modeled using load-transfer function. The method was derived to simulate various factors, including effective stress changes due to pile installation and soil reconsolidation, and effects of pile loading. By examples, it further studied that the responses of foundation average settlement, foundation difference settlement, load bearing proportion, soil reaction distributing and raft internal force with the ratio of tensile modulus to compressive modulus. The calculated result indicates that the soil reaction on for medium tall building and multistory building, elastic solution tends to obtain a lower value, and internal force of raft is inexact.