震裂岩体区软岩隧道失稳机理及安全控制对策研究
发布时间：2018-08-20 13:32
【摘要】：随着我国经济实力的大幅提升,西部大开发的逐渐深入,穿越高烈度、强震区等复杂地质条件下的隧道工程大量涌现,而上述地区强震后对原有山体形成的损伤使得原本复杂的山区环境更加艰险,隧道建设过程中遇到的技术难题更甚,频繁发生的余震也将给西部地震灾区隧道施工带来极大的安全隐患。如何有效预防和减少建设过程中隧道灾害的发生成为摆在业界学者面前的首要问题。因此,对于强震后地质条件相对复杂的西部山区隧道尤其是受地震影响严重的软岩隧道建设中亟待解决的关键技术问题开展研究具有重要的理论价值与现实意义。基于此,本文以穿越5.12汶川地震发震断裂---龙门山活动断裂带上在建的广甘高速公路隧道群为依托,针对穿越强震动力作用后形成的大量“松”而未“动”,“裂”而未“塌”的软岩隧道为研究对象,基于广泛的资料搜集与现场调研,结合现场试验、数值分析等综合研究手段,对强震后软弱岩体典型性状进行了深入剖析,并以此为基础,对震裂岩体区软岩隧道施工过程中的失稳破坏模式、成因机制及余震作用下的灾变特性及失稳机理进行了系统研究,通过现场实践,对震裂软岩隧道施工中出现的失稳破坏治理方案进行了深入探讨,取得了以下主要研究成果：(1)通过对强震区软岩隧道建设过程中揭露的大量软弱岩体资料的搜集与现场调研分析,揭示了强震区软弱岩体密度偏低、弹性波速小、透水性强及架空现象明显等基本特征,原始地应力得到一定程度释放的基本特性。(2)通过对震裂岩体区软岩隧道失稳破坏现象的大量调研,并结合现场监测数据分析,揭示了该场体条件下隧道施工期围岩-支护失稳破坏的主要特征及以溜坍为主的塌方表现形式,探明了震裂岩体区软岩隧道失稳破坏的主要发生部位。(3)基于调研统计和现场试验,结合数值模拟及理论分析,剖析了震裂软岩隧道围岩-支护失稳破坏的影响因素及成因机制,揭示出围岩自身强度低,自稳能力弱及地下水对岩体的弱化作用是震区软岩隧道发生失稳破坏的重要诱因；而支护背后的缺陷,以及设计和施工过程中对围岩特性认识不清,致使施工工法、支护措施、施工工艺等不当,也是诱发隧道发生围岩-支护失稳破坏的关键因素。(4)通过对强震区震裂软岩隧道施工期余震作用下围岩-初支结构失稳破坏典型案例分析,采用数值分析手段,剖析了不同支护结构刚度和不同地震入射方向条件下,围岩-支护结构的动力响应规律,得出了不同刚度的初支结构,其内力的动力响应规律基本一致,对于只施作了初支的隧道而言,拱腰和拱脚更易受地震作用而产生手拉破坏；揭示了余震作用下不同空洞缺陷规模及分布位置对支护结构内力影响规律,提出了地震作用并不会使空洞对衬砌的影响范围明显扩大,但会使得空洞附近产生应力集中、支护结构承载能力降低,易出现拉剪或压剪开裂等失稳破坏,探明了震裂岩体区软岩隧道施工期余震作用下的失稳机理。(5)综合震裂岩体区软岩隧道在静、动力作用下失稳破坏的影响因素及机制分析,提出了以超前加固、塌腔回填、地下水引排及加强支护为主的处治加固原则,并结合现场具体失稳破坏实例,依据上述处治原则,成功实施了试验段的整治加固,并通过现场监测,进一步验证了处治效果的可靠性,有效地控制了围岩-支护失稳段的围岩的稳定性,确保了施工的安全性,保障了施工的工程进度。
[Abstract]:Along with the great improvement of our country's economic strength, the development of the western region is deepening gradually, and a large number of tunnels have emerged under the complicated geological conditions such as high intensity and strong earthquake areas. The damage to the original mountain after the strong earthquake in the above-mentioned areas makes the original complex mountain environment more difficult and dangerous, and the technical problems encountered in the process of tunnel construction are even more serious. Frequent aftershocks will also bring great potential safety hazards to the construction of tunnels in earthquake-stricken areas of Western China. How to effectively prevent and reduce the occurrence of tunnel disasters in the process of construction has become the primary problem facing scholars in the industry. Therefore, for the tunnels in western mountain areas with relatively complicated geological conditions after strong earthquakes, especially those seriously affected by earthquakes. It is of great theoretical and practical significance to study the key technical problems in soft rock tunnel construction. Based on this, this paper takes the Guang-Gan Expressway Tunnel Group under construction across the 5.12 Wenchuan Earthquake-triggered Fault-Longmenshan Active Fault Zone as the backing, aiming at the large number of loose tunnels formed after strong seismic force. Based on extensive data collection and field investigation, combined with field test and numerical analysis, the typical characteristics of weak rock mass after strong earthquake are analyzed in depth. On this basis, the instability and failure of soft rock tunnel in seismic fractured rock mass area during construction are studied. The bad mode, genetic mechanism, catastrophic characteristics and instability mechanism under aftershocks are systematically studied. Through field practice, the treatment schemes of instability and failure in the construction of soft rock tunnel with seismic cracks are discussed in depth. The main research results are as follows: (1) A large number of soft rock tunnels exposed during the construction of soft rock tunnel in strong earthquake area are obtained. The basic characteristics of weak rock mass, such as low density, low elastic wave velocity, strong permeability and obvious overhead phenomenon, are revealed through the collection and field investigation and analysis of weak rock mass data. (2) Through a large number of investigation and Study on instability and failure of soft rock tunnel in seismic fractured rock mass area, and combined with the site investigation The monitoring data analysis reveals the main characteristics of surrounding rock-support instability and the main form of collapse in the construction period of the tunnel under the condition of the site. The main location of instability failure of soft rock tunnel in the area of fractured rock mass is found out. (3) Based on investigation statistics and field tests, combined with numerical simulation and theoretical analysis, the seismic cracking is analyzed. Influencing factors and genetic mechanism of surrounding rock-support instability failure of soft rock tunnel reveal that low strength of surrounding rock, weak self-stability ability and weakening effect of groundwater on rock mass are important causes of instability failure of soft rock tunnel in earthquake area, and the defects behind the support, as well as unclear understanding of surrounding rock characteristics in design and construction process, lead to the implementation of the tunnel. The improper construction method, support measures and construction technology are also the key factors to induce the instability failure of surrounding rock-support in the tunnel. (4) By analyzing the typical cases of instability failure of surrounding rock-initial support structure under the aftershocks in the strong earthquake zone during the construction period of soft rock tunnel, the stiffness of different supporting structures and different earthquake entry are analyzed by numerical analysis method. Under the condition of shooting direction, the dynamic response law of surrounding rock-supporting structure is obtained, and the dynamic response law of the initial support structure with different stiffness is basically the same. For the tunnel with only initial support, the arch waist and arch foot are more susceptible to earthquake and are more susceptible to hand-pulling failure. The influence law of location on the internal force of supporting structure is put forward. It is pointed out that the seismic action will not make the influence range of cavity on lining obviously enlarged, but will cause stress concentration near the cavity, reduce the bearing capacity of supporting structure, and easily lead to instability failure such as tension-shear or compression-shear cracking. (5) Based on the analysis of the influencing factors and mechanism of the instability failure of soft rock tunnel under static and dynamic action in seismic fractured rock mass area, the treatment and reinforcement principles of leading reinforcement, cave backfilling, groundwater drainage and reinforcement support are put forward, and the test section is successfully implemented according to the above-mentioned treatment principles in combination with the concrete on-site instability failure examples. Through field monitoring, the reliability of treatment effect is further verified, and the stability of surrounding rock-support instability section is effectively controlled, the construction safety is ensured and the construction progress is guaranteed.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U455
本文编号：2193797
[Abstract]:Along with the great improvement of our country's economic strength, the development of the western region is deepening gradually, and a large number of tunnels have emerged under the complicated geological conditions such as high intensity and strong earthquake areas. The damage to the original mountain after the strong earthquake in the above-mentioned areas makes the original complex mountain environment more difficult and dangerous, and the technical problems encountered in the process of tunnel construction are even more serious. Frequent aftershocks will also bring great potential safety hazards to the construction of tunnels in earthquake-stricken areas of Western China. How to effectively prevent and reduce the occurrence of tunnel disasters in the process of construction has become the primary problem facing scholars in the industry. Therefore, for the tunnels in western mountain areas with relatively complicated geological conditions after strong earthquakes, especially those seriously affected by earthquakes. It is of great theoretical and practical significance to study the key technical problems in soft rock tunnel construction. Based on this, this paper takes the Guang-Gan Expressway Tunnel Group under construction across the 5.12 Wenchuan Earthquake-triggered Fault-Longmenshan Active Fault Zone as the backing, aiming at the large number of loose tunnels formed after strong seismic force. Based on extensive data collection and field investigation, combined with field test and numerical analysis, the typical characteristics of weak rock mass after strong earthquake are analyzed in depth. On this basis, the instability and failure of soft rock tunnel in seismic fractured rock mass area during construction are studied. The bad mode, genetic mechanism, catastrophic characteristics and instability mechanism under aftershocks are systematically studied. Through field practice, the treatment schemes of instability and failure in the construction of soft rock tunnel with seismic cracks are discussed in depth. The main research results are as follows: (1) A large number of soft rock tunnels exposed during the construction of soft rock tunnel in strong earthquake area are obtained. The basic characteristics of weak rock mass, such as low density, low elastic wave velocity, strong permeability and obvious overhead phenomenon, are revealed through the collection and field investigation and analysis of weak rock mass data. (2) Through a large number of investigation and Study on instability and failure of soft rock tunnel in seismic fractured rock mass area, and combined with the site investigation The monitoring data analysis reveals the main characteristics of surrounding rock-support instability and the main form of collapse in the construction period of the tunnel under the condition of the site. The main location of instability failure of soft rock tunnel in the area of fractured rock mass is found out. (3) Based on investigation statistics and field tests, combined with numerical simulation and theoretical analysis, the seismic cracking is analyzed. Influencing factors and genetic mechanism of surrounding rock-support instability failure of soft rock tunnel reveal that low strength of surrounding rock, weak self-stability ability and weakening effect of groundwater on rock mass are important causes of instability failure of soft rock tunnel in earthquake area, and the defects behind the support, as well as unclear understanding of surrounding rock characteristics in design and construction process, lead to the implementation of the tunnel. The improper construction method, support measures and construction technology are also the key factors to induce the instability failure of surrounding rock-support in the tunnel. (4) By analyzing the typical cases of instability failure of surrounding rock-initial support structure under the aftershocks in the strong earthquake zone during the construction period of soft rock tunnel, the stiffness of different supporting structures and different earthquake entry are analyzed by numerical analysis method. Under the condition of shooting direction, the dynamic response law of surrounding rock-supporting structure is obtained, and the dynamic response law of the initial support structure with different stiffness is basically the same. For the tunnel with only initial support, the arch waist and arch foot are more susceptible to earthquake and are more susceptible to hand-pulling failure. The influence law of location on the internal force of supporting structure is put forward. It is pointed out that the seismic action will not make the influence range of cavity on lining obviously enlarged, but will cause stress concentration near the cavity, reduce the bearing capacity of supporting structure, and easily lead to instability failure such as tension-shear or compression-shear cracking. (5) Based on the analysis of the influencing factors and mechanism of the instability failure of soft rock tunnel under static and dynamic action in seismic fractured rock mass area, the treatment and reinforcement principles of leading reinforcement, cave backfilling, groundwater drainage and reinforcement support are put forward, and the test section is successfully implemented according to the above-mentioned treatment principles in combination with the concrete on-site instability failure examples. Through field monitoring, the reliability of treatment effect is further verified, and the stability of surrounding rock-support instability section is effectively controlled, the construction safety is ensured and the construction progress is guaranteed.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U455
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