摘要
分岔隧道在地下工程中应用越来越多,然而对于分岔多洞(四洞)的影响研究很少。因此,为了揭示左右线分岔四洞隧道(左匝道隧道、左主线隧道、右匝道隧道、右主线隧道)依次施工的相互影响规律,依托某隧道工程,建立左右线分岔隧道三维模型,分析施工过程中拱顶沉降、地表沉降、围岩应力、支护结构位移与应力等变化规律。重点研究了过渡段的空间变形受力特性,如过渡段位移、过渡段最大主应力与最小主应力、过渡段端头墙的位移、应力的空间分布规律,并提出相应设计与施工建议。研究结果表明:地表沉降由小净距段至大跨段逐渐增大;后行开挖左线隧道使先行右线隧道拱顶竖向位移增大;开挖对分岔大跨段的纵向位移影响最大;隧道上方围岩竖向位移由进口端至出口端逐渐增大,且左右线隧道相互影响逐渐变大;后行左线隧道的开挖,使先行右线隧道周边围岩主应力变大。过渡段支护结构主要受压,中间支撑位置存在应力集中,拉应力出现在拱顶、拱肩及仰拱部位;过渡段支护结构在水平位移上向匝道方向倾斜;在纵向位移上,向大跨段方向倾斜;在竖向位移上,上部向下变形,下部向上变形。因此,在设计施工时需要注意,在必要时进行不对称支护,施工过程中要加强支护,变形过大时注意加强,以防止失稳。
Bifurcated tunnels are increasingly used in underground engineering,however,there are few studies on the influence of bifurcation multiple holes(four holes).Therefore,in order to reveal the interaction law of the sequential construction of the left-right bifurcation four-hole tunnel(left ramp tunnel,left main line tunnel,right ramp tunnel,right main line tunnel),a three-dimensional model of the left and right bifurcated tunnels,based on the Dahengqin Mountain Tunnel Project,located in Zhuhai,Gudong province,China,was established to study the changes of vault settlement,surface settlement,surrounding rock stress displacement and stress of supporting structure during construction.The stress characteristics of spatial deformation in transition section were studied emphatically,such as the displacement of the transition section,the maximum and minimum principal stress of the transition section,the displacement of the end wall of the transition section,the spatial distribution of stress.Corresponding design and construction suggestions were put forward.The results show that:the surface subsidence gradually increases from the small clear distance section to the large span section;The vertical displacement of the vault of the right-line tunnel,which was excavated firstly,increases due to the later excavation of the left-line tunnel;Excavation has the greatest impact on the longitudinal displacement of the bifurcated long-span section;Vertical displacement of surrounding rock above tunnel increases gradually from entrance to exit;And the interaction between the left and right tunnels becomes larger;Excavation of the left tunnel makes the principal stress of surrounding rock of the right tunnel larger.As for the transition section,the supporting structure of the transition section is mainly compressed,and tensile stress only exists at arch crown,arch waist and inverted arch;Attentions should be paid to the middle support for it has stress concentration;The horizontal displacement of the support structure in the transition section is inclined to the ramp tunnel,while the longitudinal displacement is inclined to the large span;the upper part is deformed downward,and the lower part is deformed upward;Therefore,attention should be paid to the design and construction,and asymmetric support should be carried out when necessary;Support should be strengthened during construction,and attention should be paid to strengthening when the deformation is too large to prevent instability.
作者
安永林
李佳豪
雷明锋
周进
谭格宇
刘文娟
AN Yonglin;LI Jiahao;LEI Mingfeng;ZHOU Jin;TAN Geyu;LIU Wenjuan(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;School of Civil Engineering,Central South University,Changsha 410075,China;School of Material Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第8期2348-2359,共12页
Journal of Railway Science and Engineering
基金
湖南省自然科学基金资助项目(2021JJ30248,2019JJ50191)
湖南省教育厅资助项目(20A187,17C0623)。
关键词
分岔隧道
四洞施工
施工影响
力学特性
bifurcation tunnel
four tunnels construction
construction influence
mechanics characteristics
