成都某膨胀土地区支挡结构受力特征研究  

Mechanical characteristics of retaining structure in an expansive soil area of Chengdu

作　　者：孟宝华 马京京 邓宇 王宁[4] Meng Baohua;Ma Jingjing;Deng Yu;Wang Ning(Capital Construction Division,The Third Hospital of Mianyang,Sichuan Mental Health Center,Mianyang 621000,Sichuan,China;College of Modern Technology,Mianyang City College,Mianyang 621000,Sichuan,China;Chengdu Surveying Geotechnical Research Institute Co.,Ltd.of MCC,Chengdu 610023,Sichuan,China;College of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 623000,Sichuan,China)

机构地区：[1]绵阳市第三人民医院四川省精神卫生中心基本建设科,四川绵阳621000 [2]绵阳城市学院现代技术学院,四川绵阳621000 [3]中冶成都勘察研究总院有限公司,四川成都610023 [4]西南科技大学土木工程与建筑学院,四川绵阳623000

出　　处：《岩土工程技术》2025年第1期72-81,共10页Geotechnical Engineering Technique

基　　金：中冶成都勘察研究总院有限公司科研课题(ZYCK,2021-003);绵阳市第三人民医院2022年科研立项课题(202243)。

摘　　要：成都某膨胀土基坑采用h型双排桩+锚索支护,采用FLAC 3D对支护结构进行数值模拟,并从桩排间距、桩顶高差及桩底高差方面进行分析优化。分析结果表明:排距小于5d(d为桩径)时,增加排距会使桩身受力分布趋向合理;随前排桩顶降低,后排桩分担弯矩和剪力增加,但后排桩剪力最大值小于前排桩;随后排桩桩底提高,后排桩弯矩和剪力急剧减小,并出现不合理分布。根据数值分析结果对该工程h型双排桩设计进行了优化,同时在前后排桩连系梁间设置支撑盲沟,于桩间设置仰斜式泄水孔,有效地减弱了膨胀土在大量卸荷后发生松弛,避免了膨胀土因含水量增加抗剪强度降低带来的不利影响。基坑监测数据表明基坑变形控制效果较好,同时验证了数值分析模型的合理可靠性。In a foundation pit located in an expansive soil area in Chengdu,an h-type double-row pile+anchor cable support system was employed.FLAC 3D was used to conduct numerical simulations analyzing the effects of varying pile row spacing,and differences in pile top and bottom elevations.The analysis shows that when row spacings are less than five times the pile diameter(5d),increasing the spacing leeds to more reasonable force distribution on the piles.As the top of the front pile decreases,the bending moment and shear force shared by the rear pile increase,yet its maximum shear force remains lower than that of the front row.Elevating the rear row pile bottom resulted in a sharp decrease and misallocation of its bending moment and shear force.Based on these findings,the h-type double-row pile design was optimized by adding supporting blind ditches between tie beams and inclined drainage holes between piles,effectively mitigating expansive soil relaxation and preventing shear strength reduction due to moisture increases.Monitoring data confirmed effective deformation control and validated the reliability of the numerical model.

关 键 词：深基坑 膨胀土 变形监测 FLAC 3D 双排桩 

分 类 号：TU432[建筑科学—岩土工程]