高地应力偏压软岩隧道施工间距及洞形探讨  

Discussion on Construction Spacing and Tunnel Shape of Soft Rock Tunnel under High Ground Stress and Bias Pressure

作　　者：吴枋胤 何川[1] 潘文韬 杨文波[1] 寇昊 贾锋 WU Fangyin;HE Chuan;PAN Wentao;YANG Wenbo;KOU Hao;JIA Feng(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;China Construction Infrastructure Corp.,Ltd.,Beijing 100029,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031 [2]中国建设基础设施有限公司,北京100029

出　　处：《铁道标准设计》2023年第9期123-133,共11页Railway Standard Design

基　　金：中国建筑股份有限公司科技研发计划课题(CSCEC-2021-Z-26)。

摘　　要：为探究高地应力偏压软岩隧道合适施工方案,从华丽高速东马场1隧道高地应力偏压软岩引起的衬砌及仰拱非对称变形破坏出发,通过数值模拟对比不同隧道净距、顺序、纵向步距下洞周变形与塑性破坏规律,并探讨局部扩挖洞形的可行性,得出适宜的关键参数。研究结论:(1)由于后行洞对先行洞扰动,先行洞位移大于后行洞,且两者差距随净距增大逐渐减小,当净距大于3D时相互扰动效应消除;(2)偏压侧先行的洞周位移、塑性区大于偏压侧后行,净距为3D时偏压侧后行洞周变形减少23.87%,因而推荐偏压侧后行方式;(3)随着两洞掌子面距离增加,后行隧道洞周变形由于先行隧道“庇护”而减小,先行隧道洞周变形增大,掌子面距离大于50 m时“庇护”减弱,因此推荐采用≯50 m的掌子面距离并加强先行隧道支护强度;(4)偏压侧局部扩挖的洞形会导致洞周塑性区增大并有向拱底偏压侧发展的趋势,同时洞周变形均有不同程度增大(最大10%),局部扩挖洞形方案不可行。In order to explore the suitable construction scheme of soft rock tunnel with high ground bias stress,starting from the asymmetric deformation and failure of lining and invert caused by soft rock under high ground bias stress in Dongmachang No.1 Tunnel of Huali Expressway,the law of tunnel deformation and plastic failure under different tunnel clear distance,sequence and longitudinal step spacing are compared through numerical simulation.The feasibility of local expansion excavation is analyzed,and the appropriate key parameters are finally obtained.Main conclusions:(1)Due to the disturbance of the later tunnel to the leading one,the displacement of the previous tunnel is larger than that of the later one,and the gap between the two decreases gradually with the increase of the clear distance.When the clear distance is greater than 3D,the mutual disturbance effect is eliminated.(2)The displacement and plastic zone around the hole,when the tunnel on the bias side goes ahead,are larger than those when the tunnel on the bias side goes backward.When the clear distance is 3D,the deformation around the tunnel,when the tunnel on the bias side goes backward,is reduced by 23.87%,so the method with the tunnel on the bias side going backward is recommended.(3)With the increase of the distance between the two tunnel faces,the circumferential deformation of the trailing tunnel decreases due to the“protective effect”of the leading tunnel,while the circumferential deformation of the leading tunnel increases.The“protective effect”is weakened when the distance between tunnel faces is greater than 50 m.Therefore,it is recommended to adopt the distance not greater than 50 m between tunnel faces,and strengthen the support strength of the leading tunnel.(4)When the tunnel shape of partial expansion excavation on the bias side is adopted,the plastic zone around the hole increases and tends to develop towards the bias side at the bottom of the arch.Meanwhile,the deformation around the hole increases to varying degrees(up to 10%)

关 键 词：偏压软岩隧道 高地应力 隧道净距 开挖顺序 施工步距 数值模拟 

分 类 号：U25[交通运输工程—道路与铁道工程] U459.2[建筑科学—桥梁与隧道工程] U455.4