超浅埋上下重叠铁路隧道进洞施工的合理顺序分析
李元亿1涂绪虎1谢卜均1徐前卫2周峰2
Analysis of Reasonable Entry Sequence for Super Shallow Buried Overlapping Railway Tunnels
LI YuanyiTU XuhuXIE PujunXU QianweiZHOU Feng
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作者信息:1.中铁二局第五工程有限公司，610091，成都
2.同济大学道路与交通工程教育部重点实验室，201804，上海
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Affiliation:China Railway Erju No.5 Engineering Co., Ltd., 610091, Chengdu, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.2023.11.028
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中图分类号/CLCN:U455.4
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栏目/Col:施工技术
摘要:
目的：重庆市鸡公咀隧道为超浅埋上下重叠隧道，上层为预留高铁隧道，下层为铁路隧道。需对不同施工顺序下的隧道围岩的受力特性和变形特征进行对比，分析隧道之间结构扰动效应，以得到合理的施工开挖顺序。方法：简要阐述了鸡公咀隧道的工程背景、工程地质及水文地质情况。按进洞施工先后顺序推选了两个施工方案（方案一的施工次序为先建上层隧道后建下层隧道，方案二的施工次序为先建下层隧道后建上层隧道），建立了该隧道的二维有限元模型，计算模拟开挖施工过程中的地层和结构的应力特征和位移分布规律。对两种方案下隧道围岩的变形指标（包括竖向沉降、水平位移及剪应力等）计算结果进行分析，并与现场实际监测结果进行对比，以评价该模拟计算的可靠性。结果及结论：模拟计算结果和实测监测结果较为吻合。相较于方案一，方案二更有利于改善隧道结构承载性能，控制塑性区范围，降低支护结构失稳破坏风险。
Abstracts:
Objective: The Jigongju Tunnel in Chongqing City is a super shallow\|buried overlying tunnel, with the upper layer being reserved as a high\|speed rail tunnel and the lower layer being a railway tunnel. It is necessary to compare the stress characteristics and deformation features of the tunnel surrounding rock under different construction sequences, and analyze the structural disturbance effect between tunnels in order to obtain a reasonable excavation sequence for construction. Method: The engineering background, engineering geology, and hydrogeology of the Jigongju Tunnel are briefly described. Two construction schemes are proposed according to the order of tunneling (Scheme 1: upper tunnel construction followed by lower tunnel construction; Scheme 2: lower tunnel construction followed by upper tunnel construction). A 2D finite element model of the tunnel is established to calculate and simulate the stress characteristics and displacement distribution of the strata and structures during excavation. The calculation results of the tunnel surrounding rock deformation indicators under the two schemes (including vertical settlement, horizontal displacement, and shear stress) are analyzed and compared with the actual monitoring data to evaluate the reliability of the simulation calculations. Result &Conclusion: The simulation results are found to be in good agreement with the actual monitoring data. Compared with Scheme 1, Scheme 2 is more favorable for improving the structural bearing capacity of the tunnel, controlling the range of plastic deformation, and reducing the risks of support structure instability and failure.
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