隧道穿越断层破碎带围岩变形规律研究
发布时间：2019-03-04 17:46
【摘要】：随着我国高速公路建设的迅猛发展,出于隧道工程线型的要求,越来越多的隧道需穿越断层破碎带。断层破碎带内岩体一般松散破碎、自稳能力差,容易发生塌方事故。因此,研究隧道穿越断层破碎带时围岩的变形规律具有重要的理论和实际意义。本文采用三维离散元数值模拟方法,对隧道穿越不同形态的断层破碎带进行分析,得出了隧道穿越不同倾角、不同宽度、走向线与隧道轴线夹角不同的断层破碎带时围岩变形规律。同时分析研究了采用不同开挖工法穿越断层破碎带时围岩的变形规律。并结合广东揭阳小北山1号隧道穿越F2断层工程实例,研究采用预留核心土法开挖时围岩的变形规律。得到的主要结论如下:(1)隧道穿越断层破碎带时,随着断层破碎带倾角的不断增大,隧道拱顶最大沉降值、仰拱最大隆起值、拱腰最大水平位移值均呈现出"先增大后减小再增大再减小"的变化趋势,且在断层倾角为45°和135°时得到极大值。(2)当断层倾角关于90°对称(如80°和100°、60°和120°)时,隧道穿越倾角大的断层破碎带引起的拱顶最大沉降值和拱腰最大水平位移较大、引起的仰拱最大隆起值较小。(3)隧道穿越断层破碎带时,随着断层宽度的增大,隧道关键部位的变形范围和变形量都不断增大。(4)隧道穿越断层破碎带时,随着断层走向线与隧道轴线夹角的不断减小,隧道左右两侧的变形不再对称,变形区域相应增大,但关键部位变形量的变化并不大。(5)采用全断面、上下台阶、预留核心土三种不同开挖工法穿越断层破碎带时,拱顶最大沉降值、仰拱最大隆起值、拱腰最大水平位移值的排序均为:全断而上下台阶预留核心土。上下台阶法和预留核心土法引起的拱腰水平位移约为全断面法的一半;三种工法引起的拱顶沉降和仰拱隆起相差不多;采用上下台阶和预留核心土开挖时,拱顶沉降和仰拱隆起的变化趋势更加缓和,有利于结合其他围岩加固措施取得更好的效果。
[Abstract]:With the rapid development of highway construction in China, more and more tunnels need to pass through the fault fracture zone due to the requirement of tunnel line type. The rock mass in the fault fracture zone is generally loose and broken, and its self-stabilization ability is poor, so it is prone to collapse accidents. Therefore, it is of great theoretical and practical significance to study the deformation law of surrounding rock when the tunnel passes through the fault fracture zone. In this paper, the three-dimensional discrete element numerical simulation method is used to analyze the different types of fault fracture zone through the tunnel, and the results show that the tunnel passes through different angles and widths. The deformation law of surrounding rock is different between strike line and tunnel axis when the fault fracture zone is different. At the same time, the deformation law of surrounding rock when different excavation methods are used to cross the fault fracture zone is analyzed. Combined with the example of crossing F2 fault of No. 1 tunnel in Jieyang, Guangdong Province, the deformation law of surrounding rock during excavation with reserved core soil method is studied. The main conclusions are as follows: (1) when the tunnel passes through the fault fracture zone, with the increasing of the dip angle of the fault fracture zone, the maximum settlement value of the tunnel arch and the maximum uplift value of the inverted arch are obtained. The maximum horizontal displacement values of the arch waist show the trend of "increase first, then decrease, then increase and then decrease", and get a maximum when the fault inclination is 45 掳and 135 掳. (2) when the fault dip angle is about 90 掳symmetry (such as 80 掳and 100 掳, 60 掳and 120 掳), the maximum value is obtained when the fault dip angle is 45 掳and 135 掳. The maximum settlement value of arch roof and the maximum horizontal displacement of arch waist caused by the fault fracture zone with large inclined angle are larger, and the maximum uplift value of inverted arch is smaller. (3) when the tunnel passes through the fault fracture zone, with the increase of the fault width, the maximum uplift value of the inverted arch is smaller. The deformation range and deformation amount of the key parts of the tunnel are increasing constantly. (4) as the angle between the strike line of the fault and the axis of the tunnel decreases, the deformation of the left and right sides of the tunnel is no longer symmetrical when the tunnel passes through the fault fracture zone. The deformation area increases correspondingly, but the change of deformation amount in the key parts is not great. (5) when adopting full section, up and down steps and reserving three different excavation methods of core soil to cross the fracture zone, the maximum settlement value of arch roof and the maximum uplift value of inverted arch are adopted, and the maximum settlement value of arch roof and the maximum uplift value of inverted arch are obtained. The order of the maximum horizontal displacement value of the arch waist is as follows: the core soil is reserved on the upper and lower steps of the arch. The horizontal displacement of arch waist caused by the step method and the reserved core soil method is about half of that of the total section method, and the settlement of the arch roof caused by the three methods is not much different from that of the inverted arch uplift. When the upper and lower steps and reserved core soil are used for excavation, the change trend of arch settlement and inverted arch uplift is more relaxed, which is beneficial to the combination of other surrounding rock reinforcement measures to achieve better results.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4
本文编号：2434488
[Abstract]:With the rapid development of highway construction in China, more and more tunnels need to pass through the fault fracture zone due to the requirement of tunnel line type. The rock mass in the fault fracture zone is generally loose and broken, and its self-stabilization ability is poor, so it is prone to collapse accidents. Therefore, it is of great theoretical and practical significance to study the deformation law of surrounding rock when the tunnel passes through the fault fracture zone. In this paper, the three-dimensional discrete element numerical simulation method is used to analyze the different types of fault fracture zone through the tunnel, and the results show that the tunnel passes through different angles and widths. The deformation law of surrounding rock is different between strike line and tunnel axis when the fault fracture zone is different. At the same time, the deformation law of surrounding rock when different excavation methods are used to cross the fault fracture zone is analyzed. Combined with the example of crossing F2 fault of No. 1 tunnel in Jieyang, Guangdong Province, the deformation law of surrounding rock during excavation with reserved core soil method is studied. The main conclusions are as follows: (1) when the tunnel passes through the fault fracture zone, with the increasing of the dip angle of the fault fracture zone, the maximum settlement value of the tunnel arch and the maximum uplift value of the inverted arch are obtained. The maximum horizontal displacement values of the arch waist show the trend of "increase first, then decrease, then increase and then decrease", and get a maximum when the fault inclination is 45 掳and 135 掳. (2) when the fault dip angle is about 90 掳symmetry (such as 80 掳and 100 掳, 60 掳and 120 掳), the maximum value is obtained when the fault dip angle is 45 掳and 135 掳. The maximum settlement value of arch roof and the maximum horizontal displacement of arch waist caused by the fault fracture zone with large inclined angle are larger, and the maximum uplift value of inverted arch is smaller. (3) when the tunnel passes through the fault fracture zone, with the increase of the fault width, the maximum uplift value of the inverted arch is smaller. The deformation range and deformation amount of the key parts of the tunnel are increasing constantly. (4) as the angle between the strike line of the fault and the axis of the tunnel decreases, the deformation of the left and right sides of the tunnel is no longer symmetrical when the tunnel passes through the fault fracture zone. The deformation area increases correspondingly, but the change of deformation amount in the key parts is not great. (5) when adopting full section, up and down steps and reserving three different excavation methods of core soil to cross the fracture zone, the maximum settlement value of arch roof and the maximum uplift value of inverted arch are adopted, and the maximum settlement value of arch roof and the maximum uplift value of inverted arch are obtained. The order of the maximum horizontal displacement value of the arch waist is as follows: the core soil is reserved on the upper and lower steps of the arch. The horizontal displacement of arch waist caused by the step method and the reserved core soil method is about half of that of the total section method, and the settlement of the arch roof caused by the three methods is not much different from that of the inverted arch uplift. When the upper and lower steps and reserved core soil are used for excavation, the change trend of arch settlement and inverted arch uplift is more relaxed, which is beneficial to the combination of other surrounding rock reinforcement measures to achieve better results.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4
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