浅埋偏压小净距隧道施工力学效应研究
发布时间：2019-03-01 21:17
【摘要】：伴随国家交通基础设施建设的迅猛发展，，隧道工程得以广泛运用，受隧道选型、线路走向及地形地质等因素限制，越来越多的浅埋偏压大跨小净距隧道出现在工程实践中，施工过程中由于受到多重因素耦合效应，相较与常规隧道其隧道结构及围岩力学效应更复杂、施工难度、施工风险更高，如何准确把握好其施工力学效应及变形破坏机理是隧道施工与运营期间安全保障的关键。鉴于此，本文以江苏省交通科研项目-《复杂城区环境与工程地质条件下山岭隧道施工关键技术研究》为依托，采用理论分析、数值计算及现场试验相结合的研究方法，开展了浅埋偏压大跨小净距隧道施工力学效应的研究，重点探讨了施工期隧道结构与边坡变形破坏机理及控制技术。本文主要研究内容包含： (1)浅埋偏压小净距隧道施工力学特性及影响因素的分析 通过对工程原型的适当简化，运用分解叠加的等效原则对偏压隧道开挖后围岩应力场分布进行了求解，论述了影响其围岩应力分布的各项因素。鉴于此，建立数值计算模型，以隧道围岩及支护结构受力特征为分析基础，以影响偏压隧道围岩稳定性的各项因素为技术指标，系统性量化探讨了不同地形偏压角度、不同隧道埋深、不同隧道净距下围岩及支护结构力学特性。 (2)浅埋偏压小净距隧道动态施工效应及围岩稳定性的评价 运用有限元法和BP神经网络构建反分析模型，对北固山隧道先行洞施工过程中典型断面位移监测进行反演，进而确立了围岩物理力学参数；在此基础上基于现场工况建立三维数值分析模型，进行隧道动态施工全过程模拟，通过对隧道支护结构、围岩及边坡应力场、位移场分布及动态演化过程的分析研究，构建了隧道围岩-边坡体系相互作用概念模型并对其稳定性进行了评价，提出了隧道围岩-边坡体系的滑移-拉裂变形破坏模式，认为洞周围岩位移的牵引效应是影响坡体及支护结构稳定性的关键因素，隧道开挖扰动、人为削坡等外界因素在这个过程中起到了诱发作用。同时，以该体系为基本理念，为北固山隧道进口段进洞方案及施工灾害防治措施的选取提供了技术支持。 (3)隧道围岩-边坡体系变形破坏机理及灾害控制技术的研究 在隧道围岩-边坡相互作用体系构建的基础上，针对北固山隧道先行洞进洞过程中已经出现的施工灾害现象，形成了以工程地质勘察分析为基础，以隧道围岩、支护结构及边坡之间相互作用机理分析为核心，进洞过程中隧道围岩-边坡体系应力、变形实时监测为支撑的复杂地质条件下浅埋偏压小净距隧道进洞技术体系，系统阐述了该技术体系的原理、工艺。从体系整体协调与技术可行性角度出发，提出了以稳定边坡为先导、洞内外综合整治的灾害控制理念，保证了后行洞平稳进洞及整体工程的安全性。
[Abstract]:With the rapid development of national traffic infrastructure construction, tunnel engineering has been widely used. More and more shallow-buried large-span and small-net-distance tunnels appear in engineering practice, because of the factors such as tunnel type selection, line direction and topography and geology, etc, and more shallow-buried large-span and small-net-distance tunnels appear in engineering practice. Because of the coupling effect of multiple factors, the mechanical effect of tunnel structure and surrounding rock is more complicated, difficult to construct, and the construction risk is higher than that of conventional tunnel. How to accurately grasp the mechanical effect and deformation failure mechanism of tunnel construction is the key to ensure the safety of tunnel during construction and operation. In view of this, based on the traffic research project of Jiangsu Province-Research on key Technologies of Mountain Tunnel Construction under complex Urban Environment and Engineering Geology, this paper adopts the research method of combining theoretical analysis, numerical calculation and field test, The mechanical effect of shallow-buried large-span and small-clear-distance tunnel construction is studied. The mechanism and control technology of tunnel structure and slope deformation and failure during construction period are mainly discussed. The main research contents of this paper are as follows: (1) the mechanical characteristics and influencing factors of shallow-buried tunnel with small net distance are analyzed by simplifying the engineering prototype properly. The stress field distribution of surrounding rock after excavation of biased pressure tunnel is solved by the equivalent principle of decomposition and superposition, and the factors affecting the stress distribution of surrounding rock are discussed. In view of this, the numerical calculation model is established. Based on the force characteristics of surrounding rock and supporting structure of tunnel, and the factors affecting the stability of surrounding rock of biased pressure tunnel as technical index, the different topographic bias angles are discussed systematically and quantificationally. Mechanical characteristics of surrounding rock and supporting structure under different tunnel depth and net distance. (2) Evaluation of dynamic construction effect and stability of surrounding rock of shallow-buried tunnel with small net distance under bias pressure. Using finite element method and BP neural network to construct a back-analysis model, the displacement monitoring of typical cross-section in the construction process of Beigushan tunnel is inversed. Then the physical and mechanical parameters of surrounding rock are established. On this basis, a three-dimensional numerical analysis model based on site conditions is established to simulate the whole process of tunnel dynamic construction. Through the analysis and research of tunnel support structure, stress field of surrounding rock and slope, displacement field distribution and dynamic evolution process, the dynamic evolution process of tunnel support structure, surrounding rock and slope is analyzed and studied. A conceptual model of interaction between surrounding rock and slope system of tunnel is constructed and its stability is evaluated, and the failure mode of slip-pull-crack deformation of tunnel surrounding rock-slope system is put forward. It is considered that the traction effect of rock displacement around the tunnel is the key factor affecting the stability of slope and supporting structure. The disturbance of tunnel excavation and artificial cutting of slope play an important role in this process. At the same time, taking this system as the basic idea, it provides technical support for the selection of entrance scheme and construction disaster prevention measures in the entrance section of Beigushan tunnel. (3) study on deformation and failure mechanism of tunnel surrounding rock-slope system and disaster control technology based on the construction of tunnel surrounding rock-slope interaction system. Based on the engineering geological investigation and analysis, the mechanism analysis of interaction among surrounding rock, support structure and slope is formed in view of the construction disaster phenomenon that has already occurred in the process of the advance tunnel entry in Beigushan tunnel. Under the complicated geological conditions supported by the real-time monitoring of the stress and deformation of the surrounding rock-slope system in the tunnel, the technical system of tunnel entry with shallow bias and small net distance is systematically described. The principle and technology of this technology system are systematically expounded. From the point of view of overall coordination and technical feasibility of the system, the concept of disaster control, which is guided by stable slope and comprehensive treatment inside and outside the tunnel, is put forward, which ensures the safety of the smooth entry of the backward tunnel and the overall engineering.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4;U456.3
本文编号：2432810
[Abstract]:With the rapid development of national traffic infrastructure construction, tunnel engineering has been widely used. More and more shallow-buried large-span and small-net-distance tunnels appear in engineering practice, because of the factors such as tunnel type selection, line direction and topography and geology, etc, and more shallow-buried large-span and small-net-distance tunnels appear in engineering practice. Because of the coupling effect of multiple factors, the mechanical effect of tunnel structure and surrounding rock is more complicated, difficult to construct, and the construction risk is higher than that of conventional tunnel. How to accurately grasp the mechanical effect and deformation failure mechanism of tunnel construction is the key to ensure the safety of tunnel during construction and operation. In view of this, based on the traffic research project of Jiangsu Province-Research on key Technologies of Mountain Tunnel Construction under complex Urban Environment and Engineering Geology, this paper adopts the research method of combining theoretical analysis, numerical calculation and field test, The mechanical effect of shallow-buried large-span and small-clear-distance tunnel construction is studied. The mechanism and control technology of tunnel structure and slope deformation and failure during construction period are mainly discussed. The main research contents of this paper are as follows: (1) the mechanical characteristics and influencing factors of shallow-buried tunnel with small net distance are analyzed by simplifying the engineering prototype properly. The stress field distribution of surrounding rock after excavation of biased pressure tunnel is solved by the equivalent principle of decomposition and superposition, and the factors affecting the stress distribution of surrounding rock are discussed. In view of this, the numerical calculation model is established. Based on the force characteristics of surrounding rock and supporting structure of tunnel, and the factors affecting the stability of surrounding rock of biased pressure tunnel as technical index, the different topographic bias angles are discussed systematically and quantificationally. Mechanical characteristics of surrounding rock and supporting structure under different tunnel depth and net distance. (2) Evaluation of dynamic construction effect and stability of surrounding rock of shallow-buried tunnel with small net distance under bias pressure. Using finite element method and BP neural network to construct a back-analysis model, the displacement monitoring of typical cross-section in the construction process of Beigushan tunnel is inversed. Then the physical and mechanical parameters of surrounding rock are established. On this basis, a three-dimensional numerical analysis model based on site conditions is established to simulate the whole process of tunnel dynamic construction. Through the analysis and research of tunnel support structure, stress field of surrounding rock and slope, displacement field distribution and dynamic evolution process, the dynamic evolution process of tunnel support structure, surrounding rock and slope is analyzed and studied. A conceptual model of interaction between surrounding rock and slope system of tunnel is constructed and its stability is evaluated, and the failure mode of slip-pull-crack deformation of tunnel surrounding rock-slope system is put forward. It is considered that the traction effect of rock displacement around the tunnel is the key factor affecting the stability of slope and supporting structure. The disturbance of tunnel excavation and artificial cutting of slope play an important role in this process. At the same time, taking this system as the basic idea, it provides technical support for the selection of entrance scheme and construction disaster prevention measures in the entrance section of Beigushan tunnel. (3) study on deformation and failure mechanism of tunnel surrounding rock-slope system and disaster control technology based on the construction of tunnel surrounding rock-slope interaction system. Based on the engineering geological investigation and analysis, the mechanism analysis of interaction among surrounding rock, support structure and slope is formed in view of the construction disaster phenomenon that has already occurred in the process of the advance tunnel entry in Beigushan tunnel. Under the complicated geological conditions supported by the real-time monitoring of the stress and deformation of the surrounding rock-slope system in the tunnel, the technical system of tunnel entry with shallow bias and small net distance is systematically described. The principle and technology of this technology system are systematically expounded. From the point of view of overall coordination and technical feasibility of the system, the concept of disaster control, which is guided by stable slope and comprehensive treatment inside and outside the tunnel, is put forward, which ensures the safety of the smooth entry of the backward tunnel and the overall engineering.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4;U456.3
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