软土地区CFG桩群孔效应引发的地表沉降

发布时间：2018-02-03 13:47

本文关键词： CFG桩群孔地表沉降软土　出处：《天津大学学报(自然科学与工程技术版)》2017年08期 　论文类型：期刊论文

【摘要】：在软土地区CFG桩施工形成的大量空桩孔如不及时回填会产生群孔效应,造成地表沉降,进而威胁邻近建筑物、隧道及管线等基础设施的安全.本文基于某工程实测结果,利用有限元研究了单孔和多孔情况下引起的地表沉降情况及多孔叠加机理,提出了多孔合并法来解决实际工程中数量庞大的桩孔较难模拟问题,并对群孔效应引发周边严重沉降的工程进行了模拟分析.研究结果表明,单孔引发的沉降值主要受孔径影响,呈正相关;沉降最大值位置主要受孔深影响,呈线性正相关.孔心距较小时,空孔周边土体中水平和竖向上的土应力拱的相互影响与削弱导致每个空孔的内缩变形均大于单孔时的变形值,是导致群孔效应引发周边严重沉降的主要原因.群孔引发的沉降与孔数呈对数关系,孔数增大到一定值时沉降不再显著增长.所提出的多孔合并的群孔研究方法及合并转化系数?,为进一步研究群孔效应奠定了基础.
[Abstract]:If a large number of empty pile holes formed by CFG pile construction in soft soil area are not backfilled in time, they will produce group hole effect, cause surface settlement, and then threaten the adjacent buildings. Based on the measured results of a certain project, the ground subsidence and porous superposition mechanism caused by single hole and porous condition are studied by finite element method in this paper. In this paper, a porous combination method is proposed to solve the problem that a large number of pile holes are difficult to simulate in practical projects, and the simulation analysis is carried out for the engineering with serious settlement caused by the group hole effect. The settlement caused by single hole is mainly affected by pore diameter, which is positively correlated. The position of the maximum settlement is mainly affected by the depth of the hole, showing a linear positive correlation, and the center of the hole distance is small. The interaction and weakening of the horizontal and vertical soil stress arches in the soil around the hole lead to the shrinkage deformation of each hole is larger than the deformation value of the single hole. The settlement caused by the group hole is logarithmic with the number of holes. When the number of holes increases to a certain value, the settlement does not increase significantly. It lays a foundation for further study of group pore effect.
【作者单位】：滨海土木工程结构与安全教育部重点实验室(天津大学);天津大学建筑工程学院;
【基金】：国家自然科学基金资助项目(51508382,41630641) 中国博士后科学基金资助项目(2014M561186)~~
【分类号】：P642.23;TU753
【正文快照】： 在我国东部沿海地区广泛分布着工程地质条件较差的软土,具有高地下水位、高含水率、高孔隙比、高压缩性、高灵敏度、低强度、低透水性.这种软土对于城市基础设施的密集开发建设将产生不良工程地质作用,影响建(构)筑物安全.经验表明,地连墙成槽、钻孔灌注桩成孔、CFG桩钻孔、人

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