深圳某地铁车站小盾构先行大盾构扩挖施工模拟分析

李红1柯磊1李宣颍1周浩2肖波1张姣龙3,4

Simulation Analysis of A Metro Station Construction in Shenzhen with Small TBM Advancing Excavation Followed by Large TBM Enlargement

LI Hong1KE Lei1LI Xuanying1ZHOU Hao2XIAO Bo1ZHANG Jiaolong3,4
  • 作者信息:
    1.中铁五局集团第五工程有限责任公司, 423002, 郴州
    2.中铁五局集团有限公司, 550003, 贵阳
    3.同济大学土木工程学院, 200092, 上海
    4.上海同济绿建土建结构预制装配化工程技术有限公司, 200092, 上海
  • Affiliation:
    1.The Fifth Engineering Co., Ltd., China Railway No.5 Engineering Group Co., Ltd, 423002, Chenzhou, China
    2.China Railway NO.5 Engineering Group Co., Ltd., 550003, Guiyang, China
    3.College of Civil Engineering Tongji University, 200092, Shanghai, China
    4.Shanghai Tongji Green Building Prefabrication Construction Engineering Technology Co., Ltd., 200092, Shanghai, China
  • 关键词:
  • Key words:
  • DOI:
    10.16037/j.1007-869x.2024.03.017
  • 中图分类号/CLCN:
    U455.43∶U231.4
  • 栏目/Col:
    研究报告
摘要:
[目的]深圳地铁14号线(以下简称“14号线”)肿瘤医院站首次采用小盾构先行、大盾构扩挖的施工工法。鉴于目前根据已有成果难以预测小盾构先行开挖且回填后,大盾构在形成的人工复合地层中掘进引起的地层稳定性,需要对采用此种工艺施工的车站进行模拟分析。[方法]采用MIDAS/GTS软件,研究大盾构隧道开挖以及支护结构施作完成后,不同回填材料和不同埋深对地层沉降以及大盾构管片结构受力的影响。[结果及结论]当小盾构隧道分别采用C40混凝土、C15混凝土及渣土回填时,随着回填材料强度递减,大盾构开挖引起的地层位移递增,盾构管片结构的最大应力亦递增;当回填材料为C15混凝土和C40混凝土时,盾构掘进对围岩与地层的影响不大。建议本工程采用C15混凝土的回填方案;大盾构在小盾构隧道不回填的情况下直接掘进,存在较大的风险;埋深在21~45 m范围内,对地面沉降的影响不明显;随着埋深增加,地应力显著增加,隧道结构应力亦随之增加;14号线肿瘤医院站最终采取C15混凝土回填方案,地面沉降监测基本符合数值模拟计算的结果。
Abstracts:
[Objective] The new technique of small-diameter TBM (tunnel boring machine) advancing excavations followed by large-diameter TBM enlargement is used for the first time in the construction of Tumor Hospital Station on Shenzhen Metro Line 14. As the geological stability is hard to be predicted when the large diameter TBM advances in the artificial composite geological stratum, which is back-filled after the small diameter TBM excavation, it is necessary to simulate and analyze the station built with such construction technique. [Method] MIDAS/GTS software is used to simulate the effect of different backfill materials and buried depths on ground settlement and on the stress of the segment structure when the excavation of the large shield tunnel and the construction of support structure are completed. [Result & Conclusion] The analysis results show that when C40 concrete, C15 concrete and muck are respectively used as backfill materials, the stratum displacement and the maximum stress of the segment structure caused by the large excavation are increasing with the strength of the backfill material decreasing. When C15 and C40 concrete are used as backfill materials, the shield tunneling has no much effect on the surrounding rocks and geological stratum. C15 concrete is recommended as the backfill material for this project. It is highly risky that the large TBM directly drives the tunnel which is not backfilled after the small TBM tunneling. Ground settlement is insignificant when the buried depth ranges from 21 m to 45 m. But following the deepened buried depth, the ground stress increases significantly, and so does the stress of the tunnel structure.Tumor Hospital Metro Station on Shenzhen Metro Line 14 adopts the C15 concrete backfilling plan in the end, and the monitoring results of ground settlement is basically in line with the numerical simulation calculation.
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