填方灰土桩复合地基大底盘建筑倾斜特性数值分析  

Numerical Analysis of Inclination Characteristics of Large Base Buildings on Filling Lime Soil Pile Composite Foundation

作　　者：徐青 张树筱 杨宏[1] 范国堂 李哲[2] XU Qing;ZHANG Shu-xiao;YANG Hong;FAN Guo-tang;LI Zhe(China Railway 20th Bureau Group Co.,Ltd.,Xi'an 710016,China;School of Highway Engineering,Chang'an University,Xi'an 710064,China)

机构地区：[1]中铁二十局集团有限公司,西安710016 [2]长安大学公路学院,西安710064

出　　处：《科学技术与工程》2024年第14期5951-5962,共12页Science Technology and Engineering

基　　金：江苏省自然科学基金青年项目(BK20221136);长安大学中央高校基本科研业务费专项(300102212510)。

摘　　要：目前建筑倾斜事故频繁发生,但对于大底盘建筑倾斜全过程的变形力学行为受到了较少的关注。因此,研究了填方灰土桩复合地基倾斜过程的沉降变形特性及受力特性。基于数值模拟,探讨了填方灰土桩复合地基大底盘建筑倾斜特性相应变化规律,分析填方灰土桩复合地基倾斜过程中沉降变形及大底盘基础变形受力特性,研究了填方区地基处理优化方案。研究结果表明:建筑倾斜过程中,基础边缘处剪切变形最大,剪切变形值与倾斜值呈正相关;大底盘建筑倾斜过程中基础顶板混凝土首先开裂,其弯曲点不断变化;基础底板尚未开裂但底板南半段出现隆起现象,在靠近倾斜建筑0.2 L(L为底板长度)位置处存在开裂风险,倾斜过程弯曲点基本不变;水泥粉煤灰碎石桩(cement fly-ash gravel,CFG)桩地基处理方案剪应变最大值比原有方案剪应变最大值降低了67.08%,沉降值和倾斜值分别降低了67.52%、73.83%,达到此类建筑倾斜率不应超过3‰的规范要求;研究结果为类似复合地基大底盘建筑纠偏加固提供了借鉴和参考。Currently,building tilting accidents are frequently observed,but the deformation mechanics of large-scale foundation buildings throughout the entire tilting process have received relatively little attention.Therefore,the settlement deformation characteristics and stress characteristics of lime-soil pile composite foundations during the tilting process of embankment filling were investigated.The corresponding variations in the characteristics of large-scale foundation buildings with lime-soil pile composite foundations during tilting were explored based on numerical simulations.The settlement deformation and deformation-induced stress characteristics of the composite foundation during tilting were analyzed,and the optimized foundation treatment scheme for the embankment filling area was studied.The research results indicate that during the building tilting process,the maximum shear deformation occurs at the edge of the foundation,and this shear deformation value is positively correlated with the tilt angle.In the tilting process of large-scale foundation buildings,the concrete on the top of the foundation is cracked first,and its bending point keeps changing.The foundation slab has not yet cracked,but a bulge is observed in the southern half.There is a risk of cracking near the 0.2 L position of the tilted building,while the bending point remains relatively stable during the tilting process.Compared with the original scheme,the CFG(cement fly-ash gravel)pile foundation treatment scheme reduces the maximum shear strain by 67.08%,and the settlement and tilt values are reduced by 67.52%and 73.83%respectively,meeting the specification requirements that the tilt angle of such buildings should not exceed 3‰.These research findings provide a reference for the correction and reinforcement of similar composite foundation large-scale foundation buildings.

关 键 词：灰土桩 复合地基 建筑倾斜 沉降 变形力学特性 FLAC^(3D) 

分 类 号：TU473.1[建筑科学—结构工程]