下穿隧道边坡危岩崩塌滚石运动机理及安全防护
发布时间：2019-02-16 16:26
【摘要】：铁路与公路隧道在西南山区的交通建设中极为常见,是交通建设的关键,由于山区地形条件的制约,隧道连续穿山施工现象较为普遍,导致道进出洞口地段常为地形险峻、岩体破碎、危岩出露的高陡边坡地段,修建明洞结构是保证交通安全的必要手段。受到岩石风化、地震、强降雨等自然因素的影响,坡顶的危岩一旦垮塌,将对隧道明洞段造成直接冲击,严重时将导致明洞结构断裂、垮塌,对公路及铁路交通运输安全造成巨大威胁。因此,充分分析边坡滚石的运动模式、运动机理与规律,了解滚石对明洞结构的冲击特性,可为明洞段滚石的防护提供有力理论借鉴,具有重要研究意义。本文以西南山区铁路隧道为依托,通过理论分析、模型试验与数值计算等方法,研究滚石运动模式、运动机理及其对下方明洞结构的冲击影响,并结合工程实际进行滚石运动轨迹的模拟,为滚石防护设计提供参考依据。首先,将滚石冲击洞口模式进行划分,分析不同运动模式的成因,并进行冲击能量与破坏性对比,便于根据不同滚石冲击模式进行针对性的工程防护。其次,研制下穿隧道边坡危岩崩塌运动机理模型试验系统。根据不同滚石冲击运动模式建立力学模型并进行理论分析,掌握滚石运动规律；进行竖直坠落型、滑移滚动型与碰撞弹跳型冲击运动模型试验,分析明洞结构冲击速度恢复系数变化规律,研究质量与形状的变化对滚石滑移滚动运动特性的影响,并得出不同冲击模式对明洞结构的冲击破坏影响规律。再次,将试验结果与工程实际结合,建立基于可拓法的滚石冲击明洞风险评价模型,并对现场六组危岩的冲击风险进行评定,为滚石防护提供参考。最后,根据现场冲击风险性较高的三条轨迹剖面,建立数值分析模型,进行18种工况的滚石运动轨迹计算,分析滚石质量、崩塌位置与坡面特性对滚石冲击明洞的速度、能量与冲击高度等参数的影响；根据计算结果进行滚石被动防护网的布设位置、范围、高度与冲击能级的设计,并验算防护效果,结果表明,被动防护网的布设可有效防止滚石崩塌对明洞结构的冲击,为降低施工风险,保证交通安全提供有力保障。
[Abstract]:Railway and highway tunnels are very common in the traffic construction of southwest mountain area, and are the key of traffic construction. Because of the restriction of terrain condition in mountainous area, the construction phenomenon of continuous tunnel passing through the mountain is relatively common, which leads to the steep terrain in the entrance and exit of the tunnel. In the high and steep slope with broken rock mass and dangerous rock, it is necessary to build a clear tunnel structure to ensure traffic safety. Affected by natural factors such as rock weathering, earthquake and heavy rainfall, once the dangerous rock at the top of the slope collapses, it will cause a direct impact on the open tunnel section of the tunnel, and when serious, it will lead to the fracture and collapse of the structure of the open tunnel. It poses a great threat to the safety of road and railway transportation. Therefore, it is of great significance to fully analyze the movement mode, motion mechanism and law of the rolling stone in slope, and to understand the impact characteristics of the rolling stone on the structure of the open tunnel, which can provide a powerful theoretical reference for the protection of the rolling stone in the section of the open tunnel. Based on the railway tunnel in southwest mountainous area, through theoretical analysis, model test and numerical calculation, this paper studies the rolling stone movement mode, motion mechanism and its impact on the structure of the lower open tunnel. Combined with the engineering practice, the rolling stone trajectory simulation is carried out, which provides a reference for the rolling stone protection design. Firstly, the rock impact hole model is divided, and the causes of different movement modes are analyzed, and the impact energy is compared with the destructive effect, which is convenient for engineering protection according to different rolling stone impact modes. Secondly, a model test system of rock collapse mechanism of underpass tunnel slope is developed. According to the different rolling stone impact movement mode, the mechanical model is established and the theoretical analysis is carried out to master the rolling stone movement law. The impact motion model tests of vertical falling, sliding rolling and impact bouncing are carried out to analyze the change rule of impact velocity recovery coefficient of open tunnel structure, and to study the influence of mass and shape on rolling motion characteristics of rolling stone. The effects of different impact modes on the impact failure of the open tunnel structure are obtained. Thirdly, combining the test results with the engineering practice, the risk assessment model of rolling rock impact open tunnel based on extension method is established, and the impact risk of six groups of dangerous rock in the field is evaluated, which provides a reference for the protection of rolling stone. Finally, according to the three trajectory profiles with high impact risk, a numerical analysis model is established to calculate the rolling stone trajectory under 18 working conditions, and to analyze the impact velocity of the rolling stone on the open hole by the mass of the rolling stone, the location of the collapse and the characteristics of the slope surface. The influence of the parameters such as energy and impact height; According to the calculation results, the location, range, height and impact energy level of the rolling stone passive protective net are designed, and the protective effect is checked. The results show that the placement of the passive protective net can effectively prevent the impact of the rolling stone collapse on the structure of the open tunnel. In order to reduce construction risks and ensure traffic safety to provide effective protection.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U458.3
本文编号：2424629
[Abstract]:Railway and highway tunnels are very common in the traffic construction of southwest mountain area, and are the key of traffic construction. Because of the restriction of terrain condition in mountainous area, the construction phenomenon of continuous tunnel passing through the mountain is relatively common, which leads to the steep terrain in the entrance and exit of the tunnel. In the high and steep slope with broken rock mass and dangerous rock, it is necessary to build a clear tunnel structure to ensure traffic safety. Affected by natural factors such as rock weathering, earthquake and heavy rainfall, once the dangerous rock at the top of the slope collapses, it will cause a direct impact on the open tunnel section of the tunnel, and when serious, it will lead to the fracture and collapse of the structure of the open tunnel. It poses a great threat to the safety of road and railway transportation. Therefore, it is of great significance to fully analyze the movement mode, motion mechanism and law of the rolling stone in slope, and to understand the impact characteristics of the rolling stone on the structure of the open tunnel, which can provide a powerful theoretical reference for the protection of the rolling stone in the section of the open tunnel. Based on the railway tunnel in southwest mountainous area, through theoretical analysis, model test and numerical calculation, this paper studies the rolling stone movement mode, motion mechanism and its impact on the structure of the lower open tunnel. Combined with the engineering practice, the rolling stone trajectory simulation is carried out, which provides a reference for the rolling stone protection design. Firstly, the rock impact hole model is divided, and the causes of different movement modes are analyzed, and the impact energy is compared with the destructive effect, which is convenient for engineering protection according to different rolling stone impact modes. Secondly, a model test system of rock collapse mechanism of underpass tunnel slope is developed. According to the different rolling stone impact movement mode, the mechanical model is established and the theoretical analysis is carried out to master the rolling stone movement law. The impact motion model tests of vertical falling, sliding rolling and impact bouncing are carried out to analyze the change rule of impact velocity recovery coefficient of open tunnel structure, and to study the influence of mass and shape on rolling motion characteristics of rolling stone. The effects of different impact modes on the impact failure of the open tunnel structure are obtained. Thirdly, combining the test results with the engineering practice, the risk assessment model of rolling rock impact open tunnel based on extension method is established, and the impact risk of six groups of dangerous rock in the field is evaluated, which provides a reference for the protection of rolling stone. Finally, according to the three trajectory profiles with high impact risk, a numerical analysis model is established to calculate the rolling stone trajectory under 18 working conditions, and to analyze the impact velocity of the rolling stone on the open hole by the mass of the rolling stone, the location of the collapse and the characteristics of the slope surface. The influence of the parameters such as energy and impact height; According to the calculation results, the location, range, height and impact energy level of the rolling stone passive protective net are designed, and the protective effect is checked. The results show that the placement of the passive protective net can effectively prevent the impact of the rolling stone collapse on the structure of the open tunnel. In order to reduce construction risks and ensure traffic safety to provide effective protection.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U458.3
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，本文编号：2424629
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