【作者】 万飞；

【导师】 谭忠盛；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2014， 博士

【摘要】 随着经济发展的需要,公路和铁路选线以长大隧道方式通过越岭地段越来越多,修建长大隧道往往要穿越复杂的地质条件。关角隧道是新建青藏铁路西格二线的重点、难点工程,长32.605km(进口高程为3378.72m,出口高程为3324.10m),是目前世界最长的高原铁路隧道。关角隧道区内地下水发育,岩体节理、裂隙发育,穿越断层破碎带长度达2782m(单线),中等富水区17.760km,突水压力最高达2.6MPa,最大涌水量达9000～9500m3/h,施工中工作面坍塌、支护结构变形开裂、大规模突涌水现象等工程问题频发,施工非常困难和危险。本文深入研究关角隧道不良地质致灾机理及控制技术,得到以下研究成果：(1)从资料调研和工程实践入手,以定性分析方法研究关角隧道的突涌水机理。采用流量测试、联通试验等手段,明确突涌水的水源补给。基于典型突涌水实例的地质资料、超前预报资料及设计施工情况,总结出关角隧道的水文地质模型。依据关角隧道地区岩溶发育特点和长距离反坡斜井的涌水、排水特点,提出了掌子面和洞身突涌水模式,并针对突涌水模式的机理,结合理论分析和数值计算方法,提出相应的处治对策,最终形成了一套适用于西北岩溶地区特长隧道的突涌水综合防治技术。(2)采用经验总结和现场试验方法,指出裂隙-溶隙水作用在二次衬砌上的水压力分布规律具有局部高压且长期增大的特点。采用ANSYS建立荷载-结构模型,研究局部水压力作用下铁路单线隧道标准设计图的直墙和曲墙形式衬砌的受力特征和安全性,并对衬砌安全系数提高措施的作用效果进行分析,提出了局部高水压作用下衬砌的设计参数,填补了目前在局部水压显现明显地层中衬砌设计依据的不足。(3)通过调研和经验总结,定性分析地下水对岩体力学性质的影响程度,对目前常用的规范中关于地下水对围岩等级的修正规定进行了归纳总结,发现了规范中存在的不足并提出改进建议。采用理论分析的方法,推导得到了考虑渗流力时隧洞的弹塑性解。通过数值模拟,基于流固耦合理论,采用ABAQUS得到了地下水位、埋深、初期支护刚度和支护时机不同时围岩-支护结构的应力分布和变形规律,为围岩-支护结构的力学响应分析提供了依据。(4)采用现场试验,得到了富水破碎地层隧道的支护受力特征。基于松动圈理论,得到锚杆的设计长度。基于厚壁圆筒理论,得到喷射混凝土、格栅钢架、型钢钢架和组合支护体系的支护特征曲线。结合支护受力特征,提出了富水破碎围岩隧道的支护对策。(5)针对断层破碎带出现的失稳现象,采用现场试验手段,得到支护、围岩的力学特性。根据试验数据结合理论分析,对支护方案提出了改进措施。经过采用FLAC3D建立数值模型进行论证,表明改进方案可有效的限制围岩变形,降低围岩的损伤程度和地质灾害发生的可能性。基于保证安全、节省成本、缩短工期的原则,对改进方案中的径向注浆方法进一步优化,提出了纵向分区径向注浆技术。通过数值模拟手段,采用FLAC3D建立三维弹塑性模型,对纵向分区的三个主要设计参数：注浆滞后掌子面距离、注浆段落长度、注浆段落间距进行计算,得到了满足不同变形控制效果的设计参数组合。更多还原

【Abstract】 With the needs of economic development, road and rail line selection tend to be in the form of a long tunnel through the mountain areas, and the long tunnel is likely to be through complicated geological conditions. GuanJiao tunnel, the emphases and difficulties project of the newly built qinghai-tibet railway second line,32.605km long (entrance at the height of3378.72m, exit at the height of3324.10m), is the world’s longest plateau railway tunnel at present. In GuanJiao tunnel region, groundwater, rock joints and fissures rock are well developed, the length of fault fracture zone is2782m (single line), medium rich water area17.760km, water bursting pressure up to2.6MPa, and the Maximum water inflow up to9000-9500m3/h. Collapse, deformation and cracking of supporting structure, large-scale sudden flood water phenomenon were frequent in construction. The construction of GuanJiao tunnel is very difficult and dangerous. This paper studies the disaster causing mechanism and control technology of Guanjiao tunnel unfavorable geology, and obtains the following research results:(1) Starting from the data research and engineering practice, water inrush mechanism of GuanJiao tunnel is studied, based on qualitative analysis method. With the surface runoff water test and water link test, supply of water inrush is made clear, On account of geological data, forecast data, design and construction of typical examples of water inrush, hydro geological model of GuanJiao tunnel is summarized. According to the development characteristics of Guanjiao tunnel karst area and the drainage-inrush characteristics of long distance reverse slope inclined shaft, the tunnel face and excavated section inrush mode are put forward. According to the mechanism of water inrush mode, with the theoretical analysis and numerical calculation method, the corresponding countermeasures is put forward. Eventually, a set of comprehensive control technology of water inrush suitable for the long tunnel in northwest karst region is formed.(2) Using the experience summary and field test methods, the conclusion that the pressure on secondary lining of Fissure karst water has the characteristics of local high pressure and increase for a long time is made. Using ANSYS to establish the load structure model, the mechanical characteristics and safety of straight wall and curved wall lining from single track railway tunnel standard drawing under local high water pressure is studied. With analysis of the effect on improving measures to safety factor, the lining design parameters under local high pressure are put forward. The research results fill a gap in lining design basis under local high water pressure.(3) Through research and experience summary, qualitative analysis of the influence of groundwater on rock mechanical properties, revised provisions of groundwater on surrounding rock mass grade from commonly used code are summarized and some useful suggestions are given for the improvement of the revised provisions. Using the method of theory analysis, elastic-plastic solution considering seepage force on tunnel is derived. Through a numerical simulation using the ABAQUS, based on the fluid solid coupling theory, the stress distribution and deformation law of surrounding rock and support structure, with a difference of underground water level, buried depth, preliminary support stiffness and supporting time, are obtained. Based on the theory of loose ring, the design length of bolts is get. Based on the theory of thick wall cylinder, supporting characteristic curve of shotcrete, grid steel frame steel, steel frame and combined support system is get. In the end, combined with the feature of supporting force, the supporting measures in water rich and broken surrounding rock stratum is put forward.(4) Through field test, supporting structure characteristic of the tunnel in water rich and broken surrounding rock stratum is obtained. Based on the loose circle theory, the design length of the bolt is get. Based on the theory of thick wall cylinder, support characteristic curve of shotcrete, grid steel frame, steel frame and composite supporting system is get. Combined with the supporting structure characteristic, some supporting countermeasures for rich water and broken surrounding rock tunnel are put forward.(5) Aiming at the instability phenomenon of fault fracture zone, using field test method, the mechanical characteristics of support and surrounding rock is get. According to the experimental data and theory analysis, the improvement measures of support scheme are put forward. The improved scheme can effectively limit surrounding rock deformation, reduce the damage and geological disasters. It is demonstrated by using FLAC3D to establish a numerical model. Based on the principle of ensuring safety, saving cost and shortening the construction period, further optimization of the radial grouting method in improving scheme is made and a longitudinal partition radial grouting method is put forward. By means of numerical simulation, using FLAC3D to establish the three-dimensional elastoplastic model, three main design parameters of longitudinal partition, grouting distance behind tunnel face, grouting length and grouting spacing, is calculated, and design parameters group satisfying different deformation control effect is obtained.更多还原