开挖条件下非均质地基中单桩竖向承载特性非线性分析

发布时间：2018-10-05 12:22

【摘要】：在考虑开挖引起土体回弹和土体强度特性、应力状态变化的基础上,提出了开挖条件下非均质地基中竖向受荷单桩非线性计算方法,并与已有试验结果对比,证明了简化方法的正确性,并对开挖前、后单桩的竖向承载特性的变化以及开挖后土体回弹对基桩受力和变形的影响进行研究分析。研究表明,常规试桩法和套管试桩法高估了基桩竖向极限承载力和桩顶刚度,采用常规试桩和套管试桩法得到的承载力作为设计值偏于不安全;开挖卸荷引起桩周土体回弹使得桩身出现拉力,开挖深度较大时桩身中、下部的配筋应充分考虑由于开挖引起的沿桩身的拉力,防止开挖过程中基桩被拉断;桩周土体的卸荷回弹将会引起桩顶刚度的明显降低。
[Abstract]:On the basis of considering the springback and strength characteristics of soil caused by excavation and the change of stress state, a nonlinear calculation method for vertical loaded single pile in heterogeneous foundation under excavation condition is proposed, and the results are compared with the existing experimental results. It is proved that the simplified method is correct, and the variation of vertical bearing characteristics of single pile before and after excavation and the effect of soil springback on the stress and deformation of foundation pile after excavation are studied and analyzed. The results show that the vertical ultimate bearing capacity and pile top stiffness are overestimated by conventional pile test method and casing pile test method. The springback of the soil around the pile caused by excavation unloading causes the pile body to appear tensile force. When the excavation depth is high, the reinforcement in the lower part should fully consider the tensile force along the pile body caused by excavation to prevent the foundation pile from being broken in the course of excavation. The unloading and rebound of soil around the pile will obviously reduce the stiffness of the pile top.
【作者单位】：中原工学院建筑工程学院;同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;
【基金】：国家自然科学基金项目(No.51608548) 河南省科技攻关项目(No.082102360056) 郑州市科技攻关计划项目(No.10PTGG382-2)~~
【分类号】：TU473.1

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