悬浮型水泥土搅拌桩复合地基沉降及桩土应力比的颗粒流模拟  

Particle Flow Simulation of Settlement and Pile-Soil Stress Ratio of Suspended Cement-Soil Mixing Pile Composite Foundation

作　　者：朱宏栋[1,2] 张江江 程琴辉 徐芳超 陈旭 ZHU Hongdong;ZHANG Jiangjiang;CHENG Qinhui;XU Fangchao;CHEN Xu(China Northeast Architectural Design&Research Institute Co.Ltd.,Shenyang 110000,China;ZJDS Geotechnical Engineering Co.,Ltd.,Shenyang 110015,China;College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国建筑东北设计研究院有限公司,辽宁沈阳110000 [2]中建东设岩土工程有限公司,辽宁沈阳110015 [3]成都理工大学环境与土木工程学院,四川成都610059

出　　处：《烟台大学学报(自然科学与工程版)》2025年第1期81-91,共11页Journal of Yantai University(Natural Science and Engineering Edition)

基　　金：四川省科技计划(应用基础研究)(2021YJ0394)。

摘　　要：为了探明悬浮型水泥土搅拌桩复合地基的沉降及桩土应力比特性,利用离散元软件PFC2D建立二维单桩复合地基颗粒流模型,从细观层面上模拟不同悬浮度和水泥掺入比的复合地基变形和承载特性,分析复合地基沉降、桩土应力比、颗粒黏结破坏、接触力链和能量变化规律。模拟结果表明:随着桩悬浮度的增加,复合地基沉降减小,悬浮度68%和76%复合地基桩土应力比表现出先增大后稳定的趋势,悬浮度84%、92%和100%复合地基桩土应力比表现出先增大后减小的趋势;随着桩水泥掺入比的增加,复合地基沉降减小,水泥掺入比10%、15%、20%、25%复合地基桩土应力比均表现出先增大到峰值然后减小的趋势,且峰值增大的幅度逐渐减小;端承型比其余四种悬浮型水泥土搅拌桩复合地基更容易发生破坏,在桩端和桩身上部产生大量黏结断裂形成的宏观裂纹,宏观裂纹在应变能的驱动下进一步扩展,扩展过程中摩擦能超越应变能逐渐占主导地位,破坏处部分力链断裂消失或颜色变浅,部分力链相比于桩其他区域更粗,颗粒间出现了接触力集中现象,最终导致复合地基因桩身强度破坏丧失承载力。To explore the settlement and pile-soil stress ratio characteristics of suspended cement-soil mixing pile composite foundations,a two-dimensional particle flow model of single-pile composite foundation was established using the discrete element software PFC2D.The deformation and bearing characteristics of the composite foundation with varying degrees of suspension and cement mixing ratios were simulated from a meso-scopic perspective,and the settlement of composite foundation,pile-soil stress ratio,particle bond failure,contact force chain and energy change law were analyzed.The simulation results show that with the increase in pile suspension degree,the settlement of the composite foundation decreases.The pile-soil stress ratio of the composite foundation with 68%and 76%suspension degree initially increases and then stabilizes.For composite foundations with suspension degree of 84%,92%,and 100%,the pile-soil stress ratio initially increases and then decreases.With the increase in pile cement mixing ratio,the settlement of the composite foundation decreases.The pile-soil stress ratio of composite foundations with cement mixing ratios of 10%,15%,20%and 25%exhibits a trend of first increasing to a peak and then decreasing,with the peak amplitude gradually decreasing.The end bearing type is more prone to damage than the other four types of suspension cement-soil mixing pile composite foundations.Numerous macro cracks,formed by bond fracture,are generated at the pile end and the upper part of the pile body.These macro cracks expand further under the influence of strain energy.During the expansion process,friction energy exceeds strain energy and gradually becomes dominant.Some force chains at the damage site break and disappear or become lighter in color,while some force chains are thicker than those in other areas of the pile,leading to concentration of contact forces between particles and ultimately resulting in the composite foundation losing its bearing capacity due to strength failure of the pile body.

关 键 词：悬浮型水泥土搅拌桩 地基沉降 桩土应力比 颗粒流 悬浮度 水泥掺入比 

分 类 号：TU44[建筑科学—岩土工程]