【作者】 李振；

【导师】 郭院成； 靳军伟；

【作者基本信息】 郑州大学 ， 建筑与土木工程， 2020， 硕士

【摘要】 随着我国经济的快速发展和城市化进程的加快,城市地下空间综合体的开发与利用,地下连通道、管廊等新建隧道与既有地铁隧道近接影响问题逐渐凸显。实际工程中,许多连通道或管廊采用箱涵顶进施工工艺,但在该方面的研究却尚不完善,因此研究箱涵顶进施工对既有隧道的影响规律,是目前亟待解决的一个重要问题,本论文的完成,为类似的工程提供有效的参考。本课题依托郑州某地下交通枢纽地下连通道项目,地下连通道采用箱涵顶进施工工艺,同时地下连通道上穿跨越郑州地铁1号线。采用有限元方法,建立模拟箱涵顶进上穿既有地铁隧道施工过程的三维数值分析模型,分析箱涵顶进施工过程中既有隧道的变形规律。同时,对箱涵顶进施工影响既有隧道变形的主要因素进行综合分析。最后,结合工程案例进行既有隧道加固条件下的案例分析,研究主要内容与结论如下:(1)依托工程背景,系统的介绍了地下连通道的整体结构、箱涵顶进施工中的总体施工方案,以及箱涵结构顶进工艺流程与施工技术。(2)利用有限元方法建立箱涵顶进水平垂直穿越下部既有地铁隧道的数值分析模型,模拟分析了地铁隧道在箱涵顶进过程中的竖向位移、水平位移规律以及土体位移规律。研究发现:箱涵顶进施工对下卧既有隧道的影响是三维的,包含竖向和水平方向的影响,随着顶进施工的进行既有隧道竖向与水平位移值不断增大,顶进完成后隧道整体发生上抬及向箱涵顶进方向的前方移动,隧道距离箱涵越近变形值越大,且箱涵在穿越既有隧道时隧道的变形速率最大。随着箱涵顶进距离的增加,土体竖向位移值与影响范围逐渐增大而且是呈空间性扩散。(3)分别对不同土质、箱涵与隧道不同距离、箱涵与隧道不同位置、箱涵不同大小时箱涵顶进施工引起既有隧道的变形规律进行了研究。研究表明:当既有隧道所处地质条件较为复杂或土质较软时既有隧道的变形会增大;既有隧道位移值随箱涵与隧道的垂直距离增加而逐渐减小;箱涵与既有隧道所处空间位置不同时隧道变形规律有所变化,对称顶进能有效减小对既有隧道的影响;随着箱涵宽度的增加既有隧道位移值逐渐增加,竖向位移增长率逐渐增大但水平位移增长率有所波动。(4)依托工程案例,针对土体注浆加固和抗拔桩管幕加固两种加固措施对隧道变形控制效果进行了建模数值分析。研究表明:在箱涵顶进范围内土体注浆加固能减小隧道竖向位移值,但隧道水平位移值减小不明显;抗拔桩与管幕门式加固能有效减小既有隧道竖向位移值与水平位移值,且隧道变形减小幅度较大尤其是水平向变形。更多还原

【Abstract】 With the rapid development of China’s economy and the acceleration of the urbanization process,the development and utilization of urban underground space complexes,the impact of new tunnels such as underground connecting passage and pipe gallery close to the existing subway tunnel gradually highlights.In actual engineering,many connecting passages or pipe corridors adopt box culvert jacking construction technology,but the research in this filed is not perfect.Therefore,it is an important problem to be solved urgently to study the influence law of box culvert jacking construction on existing tunnels.The completion of this paper provides an effective reference for similar projects.This subject relies on the underground connecting passage project of an underground transportation hub in Zhengzhou.The underground connecting passage adopts the construction process of box culvert jacking,and at the same time the underground connecting passage crosses the Zhengzhou Metro Line 1.The finite element method was used to establish a three-dimensional numerical analysis model that simulates the construction process of box culvert jacking through an existing subway tunnel,and analyzes the deformation law of the existing tunnel during box jacking.At the same time,a comprehensive analysis of the main factors that affect the deformation of the existing tunnel during the jacking construction of the box culvert.Finally,combining with the engineering case,the paper analyzes the case of existing tunnel reinforcement.The main contents and conclusions of the study are as follows:(1)Based on the engineering background,the overall structure of the underground connecting channel,the overall construction plan in the jacking construction of the box culvert,and the technological process of the jacking construction of the box culvert structure are systematically introduced.(2)The numerical analysis model of box culvert jacking horizontally and vertically crossing the existing subway tunnel is established by finite element method.The vertical displacement,horizontal displacement law and soil displacement law of the subway tunnel during jacking of the box culvert are simulated and analyzed.It is found that the impact of the jacking construction of the box culvert on the existing tunnel underneath is three-dimensional,including the vertical and horizontal effects.With the increasing of vertical and horizontal displacement values of the existing tunnel during the jacking construction.After the jacking is completed,the tunnel ascends and moves forward in the direction of jacking of the box culvert.The closer the tunnel is to the box culvert,the larger the deformation value of the tunnel is,and the deformation rate of the tunnel is the largest when the box culvert passes through the existing tunnel.With the increase of the jacking distance of the box culvert,the vertical displacement value and the influence range of the soil gradually increase and spread spatially.(3)The deformation laws of the existing tunnel caused by the jacking of the box culvert under different soil quality,different distances between the box culvert and the tunnel,different positions of the box culvert and the tunnel,and different sizes of the box culvert are studied.The research shows that the deformation of the existing tunnel will increase when the geological conditions of the existing tunnel are more complex or the soil is softer;the displacement value of the existing tunnel gradually decreases with the increase of the vertical distance between the box culvert and the tunnel;The deformation law of the tunnel changes when the spatial position of the tunnel is different.Symmetric jacking can effectively reduce the impact on the existing tunnel;as the width of the box culvert increases,the displacement value of the existing tunnel increases gradually,and the vertical displacement growth rate increases but the horizontal displacement growth rate fluctuates.(4)Based on the engineering case,the numerical simulation analysis of the tunnel deformation control effect is carried out for the two reinforcement measures: soil grouting reinforcement and uplift pile pipe screen reinforcement.The research shows that the grouting reinforcement of the soil within the jacking range of the box culvert can reduce the vertical displacement value of the tunnel,but the horizontal displacement value of the tunnel does not decrease significantly;the vertical displacement and horizontal displacement of the existing tunnel can be effectively reduced by the anti pulling pile and the pipe curtain door reinforcement,and the tunnel deformation is greatly reduced,especially the horizontal deformation.更多还原