【作者】 郭磊；

【导师】 傅鹤林；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2010， 博士

【摘要】 21世纪是地下工程的世纪,隧道往往成为跨海和跨江河的首选穿越方案。传统浅埋暗挖方法在水下隧道施工中遇到许多问题,成为隧道工程界的难点和热点问题。本文结合长沙市科技计划项目“水下软岩隧道浅埋暗挖矿山法施工的关键控制技术开发应用”、中铁隧道集团立项的科技攻关项目“浅埋暗挖水下隧道施工关键技术研究”和国家自然科学基金(50878213),以浏阳河水下隧道为背景,展开浅埋暗挖水下隧道管棚预支护作用机理、水渗流作用下开挖的扰动效应研究。研究过程中,针对隧道不同位置,即浅埋暗挖小间距段和分离段,分别展开研究。主要工作内容为：1)对目前国内外隧道管棚预支护理论进行较系统的总结。结合水下隧道,研究管棚预支护作用机理及有待进一步研究的问题。在此基础上,运用管棚预支护理论分析水下隧道浅埋暗挖中支护结构的设计参数；2)以连续地基梁理论为基础,建立管棚支护结构与围岩相互作用模型；推导管棚结构的挠度方程、转角、弯矩方程及地基反力方程,建立了基于连续地基梁反力方程的隧道开挖面边坡稳定评价模型。3)小间距隧道开挖的扰动效应,即：(1)分析隧道在不同施工方法和不同开挖顺序开挖后围岩变形的空间效应；(2)确定隧道开挖管棚支护后引起的围岩变形的幅度和范围；(3)找出隧道开挖最不利荷载工况和结构薄弱部位,为施工方案的制定提供理论依据和决策支持；4)水下洞身浅埋暗挖段隧道开挖的扰动效应,即：(1)从渗流连续性方程和渗流运动方程出发,在多孔介质中的饱和渗流的基本方程的基础上,并基于Biot固结理论,推导求解水下隧道围岩与水耦合问题的渗流微分方程组及定解条件；(2)综合考虑流固耦合效应以及围岩与管棚支护结构共同作用,改进了以往数值方法在反映隧道流固耦合效应方面的不足,建立能同时反映岩土体力学特性和水体流动规律的流固耦合模型；(3)针对三维有限差分程序FLAC3D的流固耦合计算功能,系统研究FLAC3D求解流固耦合问题的建模方法,并对FLAC3D进行二次开发,确保流固耦合相互作用的各个方程在FLAC3D中得到实现。在此基础上,采用FLAC3D模拟浏阳河水下隧道施工,分析不同水位下,动态开挖对围岩稳定性及地表沉陷的扰动影响。更多还原

【Abstract】 In 21st century, underground engineer will be very common, and the tunnel across sea or river will be first selection schedule. Many technical problems caused by excave under shallow layer will become the hot point which focused by researchers. Combined with the projects "study on key problem and its application of construction in thin soft rock layer under water"(sponsored by Changsha Bureau of science)、"study on key problem of construction in thin soft rock layer under water"(sponsored by China Tunnel limited Group) and Chinese Natural found(No.50878213),with the background Liuyanghe under river tunnel engineering, the principle of roof supporting tube and the influence on rockmass stability deduced by water penetration is analyzed in this disseration. In the period of research, consideration of different site, i.e tunnels in small distance or separated state, the research work are singlely done. The main content includes followings:1) Summary of reinforcement principle of roof pre-supporting tube is made. Combined with the underwater tunnel, and on the base of detail analysis,the selection of supporting structure and parameters of roof pre-supporting tube is realized.2) Depended on continuous beam theory, the interaction model of roof pre-supporting tube and surrounding rockmass is founded. With interruption format,turning angel and tension moment and anti-force fonnat of roof pre-supporting tube, the analysis model of excave face stability is established.3)Construction method about tunnels construction in small distance and realibity of roof pre-supporting tube are studied, i.e.:(1)The space effect of rockmass deduced by excave in different construction methods and different construction schedule.(2) the height and scope of space effect of rockmass after reinforcemented by roof supporting tube is determined.(3) After the disadvantage of loads combination and weak site in tunnel during excave being obtained, the theoretical clue and decision policy of construction schedule will be got.4) Construction method about tunnels construction in separated state and realibity of roof pre-supporting tube are studied, i.e.(1) Expounded the basic equation for saturated seepage in porous media basing on the seepage continuity equation and the seepage movement equation, and gave forth a group of partial differential equations for seepage in fluid-solid coupling cases and the deterministic condition of solution inferred from the Biot Consolidation Theory.(2) Simulated the construction of Liuyang River Underwater Tunnel basing on FLAC-3D numerical methods, improved upon the traditional numerical methods in representing fluid-solid coupling effects, taking accounts of both the fluid-solid coupling effects and the combined action of wall rocks and shoring structures, established fluid-solid coupling models to represent soil-rock mechanical characteristics and water flow, and analyzed the mechanical effects of the underwater tunnel during each construction stage.(3) With the second development of F1AC-3D, the representation of each equation for fluid-solid coupling interaction in the three-dimensional differential procedure FLAC-3D, and the general modeling methods in FLAC-3D for solution is realized. And then the, the stability of excave face and surface settlement caused by excave in different water levels, are all acquired.更多还原