摘要
以某高速公路小净距增建隧道工程为依托,在既有隧道衬砌裂损情况调研基础上,采用数值分析方法对Ⅳ级围岩条件下,邻近既有裂损隧道增建隧道施工工法进行比选研究,进而评估不同工法条件下裂损隧道结构受力、围岩变形特征,最终确定增建隧道合理施工工法。研究结果表明:(1)增建隧道采用不同组合工法施工时,隧道周围围岩变形、新老隧道结构受力均满足围岩变形能力和衬砌材料承载能力要求,但均采用交叉中隔墙法施工时隧道结构安全性最高;(2)增建隧道采用不同组合工法施工时老隧道衬砌裂损部位均出现拉应力集中现象,且均采用交叉中隔墙法施工时裂损处拉应力最小;(3)增建左右线隧道分别采用交叉中隔墙法和三台阶七步法、三台阶七步法和三台阶七步法组合工法施工时隧道拱脚部位围岩出现较小塑性区,而均采用交叉中隔墙法施工时围岩周边未产生塑性区;(4)综合分析建议,Ⅳ级围岩段增建左右线隧道施工均宜采用交叉中隔墙法。
Based on the small-clear distance additional tunnel project of an expressway,and on the basis of the investigation of the existing tunnel lining crack damage,this paper adopts numerical calculation to study the construction method of additional tunnel adjacent to the existing crack tunnel under the conditions of Class IV surrounding rock,and then evaluates the structural stress on cracked tunnel and deformation characteristics of the surrounding rock under different construction conditions.Finally,the reasonable construction method of the additional tunnel is determined by comparison.The results show that:(1)the deformation of surrounding rock and the load-bearing capacity of new and old tunnel structures meet the requirements of the deformation capacity of surrounding rock and the bearing capacity of lining materials when different combined construction methods are used to construct the additional tunnels,but the tunnel structure safety is the highest when constructed using the cross diaphragm(CRD)method.(2)Tensile stress concentration occurred at the crack damage of the old tunnel lining when different combined construction methods are used,and the tensile stress at the crack damage is the smallest when constructed using the cross diaphragm(CRD)method.(3)The cross diaphragm(CRD)method and three-bench seven-step combination construction method are used to construct the additional left and right line tunnel separately,a small plastic zone showed up in the surrounding rock at the arch foot of the tunnel,while there is no plastic zone around the surrounding rock when using the cross diaphragm(CRD)method to construct the tunnel.(4)The comprehensive analysis suggests that the cross diaphragm(CRD)method is recommended for the construction of additional left and right line tunnels in the surrounding rock section of ClassⅣ.
作者
白秀峰
BAI Xiufeng(Beijing Tiecheng Engineering Consulting Co.Ltd.,Beijing 100086,China)
出处
《铁道建筑技术》
2024年第10期104-107,146,共5页
Railway Construction Technology
关键词
裂损隧道
增建隧道
小净距
数值计算
工法比选
cracked tunnel
additional tunnel
small-clear distance
numerical calculation
comparison and selection of construction method
