天然饱和黏土地基静压桩承载力时效性研究

发布时间：2018-01-11 05:28

本文关键词：天然饱和黏土地基静压桩承载力时效性研究　出处：《岩土力学》2017年09期 　论文类型：期刊论文

【摘要】：分别以柱孔和球孔扩张模拟桩身和桩端的贯入过程,采用可以考虑天然饱和黏土应力历史和应力各向异性的圆孔扩张解答描述桩周土体的应力状态,推导了饱和黏土地基中静压桩终压力的理论解,进而基于桩周孔压径向消散的固结解答,在考虑桩周土再固结过程中松弛效应的基础上,推导了沉桩结束后静压桩时变承载力的解答,建立了静压桩承载力时效性系数的理论表达式。通过离心模型和现场试验对所提的理论解答的正确性进行了验证,研究了天然饱和黏土中静压桩承载力的时效性。结果表明:沉桩结束后较短时间内静压桩承载力时效性是超孔压消散和土体触变恢复共同作用的结果,一定间歇期后超孔压消散成为承载力增长的主要原因。
[Abstract]:The penetration process of the pile body and the pile end is simulated by the expansion of the column hole and the spherical hole, and the stress state of the soil around the pile is described by the circular hole expansion solution which can take into account the natural saturated clay stress history and the stress anisotropy. The theoretical solution of the ultimate pressure of static pile in saturated clay foundation is derived, and based on the consolidation solution of radial dissipation of the pore pressure around the pile, the relaxation effect of the soil around the pile is considered. The solution of time-varying bearing capacity of static pressure pile after the end of pile-sinking is derived, and the theoretical expression of time-efficiency coefficient of bearing capacity of static pile is established. The correctness of the theoretical solution is verified by centrifugal model and field test. The time effect of bearing capacity of static pressure pile in natural saturated clay is studied. The results show that the time effect of bearing capacity of static pressure pile in a short time after the end of pile sinking is the result of superpore pressure dissipation and soil thixotropic recovery. The dissipation of superpore pressure is the main reason for the increase of bearing capacity after a certain interval.
【作者单位】：同济大学岩土及地下工程教育部重点实验室;同济大学地下建筑与工程系;上海大学土木工程系;
【基金】：国家自然科学基金项目(No.41272288)~~
【分类号】：TU473.1
【正文快照】： 天然饱和黏土中静压桩承载力的时效性一直是工程界和学术界普遍关心的课题之一[1-6]。通常,在桩沉入土体一定休止期后,需进行静载荷试验以确定单桩极限承载力是否满足设计承载力。然而,由于天然饱和黏土中静压桩承载力具有明显的时效性,特定休止期后测试所得承载力难以准确衡

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