土岩组合地层异形深基坑支护体系优化研究
摘要:某明挖隧道基坑位于土岩组合地层，基坑大面深度约17.1 m，深挖部位约27.9 m，原设计整体基坑采用地下连续墙+4道钢筋混凝土支撑，坑中坑内侧壁采用钻孔灌注桩作为竖向支护结构，深坑部位加设2道钢管支撑。为节约工期和工程造价，综合考虑地层分布及地质条件，对原设计方案进行了系列优化。运用数值模拟对比分析了优化前后基坑支护体系和周边环境的变形特性，结果表明优化后的支护方案满足设计和规范要求。基坑按优化方案施工，并开展了现场监测工作，基坑监测结果表明：（1）基坑连续墙水平位移、地表沉降、支撑轴力、周边建筑物变形及坑底隆起等指标均小于控制要求；（2）连续墙最大水平位移发生在土岩分界面以上一定高度，最大值约为浅基坑深度的0.025%；（3）异形基坑两侧变形不对称，最大地表沉降发生在浅基坑侧，基坑外地表影响范围约为1.0H；（4）下部基岩段基坑开挖侧向变形量小，且对地表沉降槽范围影响不大。优化方案节约了工期和造价，可为类似基坑工程提供参考。
Abstract:The foundation pit of a certain open-cut tunnel is located in a soil-rock combination layer, with a large depth of about 17.1 m and a deep excavation area of about 27.9 m. The original design of the overall foundation pit used underground continuous walls and 4 reinforced concrete supports, and the inner wall of the pit used drilled cast-in-place piles as vertical support structures. Two steel pipe supports were added to the deep pit area. To save construction period and project cost, a series of optimizations have been made to the original design scheme, taking into account the distribution of strata and geological conditions. Numerical simulation was used to compare and analyze the deformation characteristics of the foundation pit support system and surrounding environment before and after optimization. The results showed that the optimized support scheme met the design and regulatory requirements. The foundation pit was constructed according to the optimized plan and on-site monitoring work was carried out. The monitoring results of the foundation pit showed that: (1) The horizontal displacement of the continuous wall of the foundation pit, surface settlement, support axial force, deformation of surrounding buildings, and uplift at the bottom of the pit were all below the control requirements; (2) The maximum horizontal displacement of the continuous wall occurs at a certain height above the soil rock interface, with a maximum value of approximately 0.025% of the shallow foundation pit depth; (3) The deformation on both sides of the irregular foundation pit is asymmetric, and the maximum surface settlement occurs on the shallow foundation pit side. The impact range of the outer surface of the foundation pit is about 1.0H; (4) The lateral deformation of the foundation pit excavation in the lower bedrock section is small, and it has little impact on the range of surface settlement grooves. The optimization plan saves time and cost and can provide a reference for similar foundation pit projects.
中文标题：
土岩组合地层异形深基坑支护体系优化研究
Optimization of Support System for Deep Foundation Pit with Special-shaped Soil-rock Combination Strata
作者：
吉艳雷
Ji Yanlei
作者简介:吉艳雷，男，1982年生，汉族，山西运城人，硕士，高级工程师，注册土木工程师（岩土），从事地下工程设计研究工作。E-mail：365941113@qq.com
通讯地址：
陕西省铁道及地下交通工程重点实验室（中铁一院），陕西西安 710043
ShaanxiRailwayandUndergroundTrafficEngineeringKeyLaboratory(FSDI),Xi'an710043,Shaanxi,China
中图分类号:TU473
doi:10.3969/j.issn.1007-2993.2024.01.009
出版物：岩土工程技术
收稿日期:2022-02-15
修回日期:2023-08-05
录用日期:2023-11-08
刊出日期:2024-02-05
关键词:土岩组合,异形,基坑支护,方案优化,喷锚,数值模拟
Key words:soil-rock combination,special-shaped,foundation pit support,scheme optimization,spray anchoring,numerical simulation
文档包含图片数量：图片(11)张
文档包含表格数量：表格(3)个
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基金项目：
基金项目:中铁第一勘察设计院科研项目（院科20-01）
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