(1 国网河北省电力有限公司经济技术研究院, 石家庄 050000; 2 河北大学建筑工程学院, 保定 071002)

摘要: 为了研究非均匀地基不同区域桩长变化对桩筏基础沉降特性的影响,以某变电站桩筏基础工程为背景,采用 PLAXIS 3D 软件建立上部荷载⁃桩筏基础⁃非均匀地基三维有限元模型,分析了 4 种非等桩长设计方案下的筏板与地基沉降变形特性. 结果表明:筏板沉降分布形态、最大沉降量及其出现的位置均随筏板下不同区域桩长的变化而变化. 方案 1 和方案 2 的桩长随持力层顶面埋深变化而变化,桩端进入较硬的持力层,但筏板下不同区域的桩长差异较大,筏板沉降非对称分布,最大差异沉降 13. 70~ 15. 13mm;方案 4 为等桩长,但由于土层分布不均匀,不同区域的桩侧阻力和桩端阻力发挥各异,筏板沉降亦为非对称分布,最大差异沉降仍达 12. 57mm;方案 3 各区桩长变化较小,筏板沉降分布相对较为均匀,其最大沉降量和差异沉降相比方案 1 分别降低 22. 8%和 37. 5%,说明此时桩长与土层分布相协调,沉降控制效果较好.

关键词: 桩筏基础; 非均匀地基; 变桩长; 沉降; 协同分析

中图分类号:TU473. 1 文献标志码:A 文章编号:1002⁃848X(2022)08⁃0124⁃07

DOI:10. 19701 / j.jzjg.20210625

Three dimensional finite element cooperative analysis of settlement control of variable pile lengthin non⁃uniform foundation

WU Hailiang1, XING Lin1, ZHANG Wuchen1, ZHANG Haiqing2

(1 Economic and Technological Research Institute, State Grid Hebei Electric Power Co., Ltd., Shijiazhuang 050000,China; 2 College of Civil Engineering and Architecture, Hebei University, Baoding 071002, China)

Abstract: In order to study the influence of pile length changes in different areas of non⁃uniform foundation on thesettlement characteristics of pile⁃raft foundation, taking the pile⁃raft foundation project of a substation as the background,the PLAXIS 3D software was used to establish a three⁃dimensional finite element model of upper load⁃pile⁃raft foundation⁃non⁃uniform foundation, and the settlement and deformation characteristics of the raft and foundation under four unequalpile length design schemes were analyzed. The results show that the distribution form of the raft settlement, the maximumsettlement value and its occurrence position all change with the change of the pile length in different areas under the raft.The pile lengths of scheme 1 and scheme 2 change with the buried depth of the top surface of the bearing layer, and the pileends enter the harder bearing layer. But the pile lengths in different areas under the raft are quite different, and the raftsettlement is distributed asymmetrically. The maximum differential settlement is 13. 70~ 15. 13mm. Scheme 4 is equal to thelength of the pile, but due to the uneven distribution of soil layers, and the pile side resistance and pile end resistance indifferent areas play different roles, and the raft settlement is also asymmetrically distributed, and the maximum differentialsettlement is still up to 12. 57mm. The change of pile length in each area of scheme 3 is small, and the distribution of raftsettlement is relatively uniform. Compared with scheme 1, the maximum settlement and differential settlement of scheme 3are reduced by 22. 8% and 37. 5% respectively, which shows that the pile length is suitable for the distribution of soillayer, and the settlement control effect is fairly good.

Keywords:pile⁃raft foundation; non⁃uniform foundation; variable pile length; settlement; collaborative analysis

∗国网河北省电力有限公司科技项目资助“基于数值模拟的变电站软弱地基分析技术研究”(B704JY200081).

第一作者:吴海亮,硕士,工程师,主要从事变电站结构设计工作,Email:463289609@ qq.com.

[引用本文] 吴海亮,邢琳,张戊晨,等. 非均匀地基变桩长沉降控制三维有限元协同分析[ J]. 建筑结构,2022,52(8):124⁃130,65. WU Hailiang, XING Lin, ZHANG Wuchen, et al. Three dimensional finite element cooperative analysisof settlement control of variable pile length in non⁃uniform foundation[J]. Building Structure,2022,52(8):124⁃130,65.