中梁山1号隧道上穿二岩铁路隧道的影响分析

发布时间：2019-06-05 19:04

【摘要】：随着交通的不断发展交通路线变得越来越复杂，规划路线与原有交通路线交叉屡见不鲜。在隧道领域必然就会存在在建隧道上穿或者下穿已建隧道的情况。新建隧道近距离穿越既有隧道时，由新建隧道的开挖对土体的扰动引起土层的变形和隧道结构的附加内力，如果既有隧道结构的变形超过了设计极限就会导致隧道结构破坏以致影响既有隧道的安全运营。目前对交叉隧道的研究以新建隧道上穿既有隧道的研究为主，下穿的研究相对较少，对于出现的很多新问题还无法解决，设计、施工还没有相应的规范、标准可循。因此，只有充分认识新建隧道上穿对既有隧道的影响方式和影响程度，才能确定可行的设计、施工方案，保证既有隧道的运营安全。本文在理论分析的基础之上，结合轨道交通地铁6号线中梁山1号隧道上穿二岩铁路隧道工程实例，通过有限元数值模拟以及现场监测数据分析，对新建隧道上穿既有二岩铁路隧道的影响进行研究。主要内容包括： ①由理论分析可以知道，地质、施工、结构、净距等因素都在一定程度上直接或间接的影响到新建隧道开挖时既有铁路隧道的安全运营。 ②通过实际的现场监测可知，新建隧道开挖引起的既有铁路隧道竖向位移表现出穿越前沉降，，穿越时隆起，穿越后继续隆起。最大的沉降量和隆起量都出现在新建隧道和既有隧道的交汇处，变化趋势大致为抛物线。对于既有隧道的净空收敛变形情况反映了铁路隧道支护结构力学形态和围岩最直接的参数，通过净空收敛监测可以知道围岩和支护结构的稳定情况。新建隧道的开挖由于土体卸载，周围的土应力释放发生弹塑性变形，既有铁路隧道整体上浮，穿越后整体趋于稳定。 ③通过MIADAS-GTS数值模拟可以知道，随着新建隧道的开挖，既有二岩铁路隧道的竖向位移量不断的增大。其变化趋势呈抛物线，不同的工况下变化趋势基本相同，变化量略有不同。由数值模拟可以看出新建一号隧道对既有二岩铁路隧道的影响主要以竖向位移为主。 ④两交叉隧道的净距不同对既有隧道的影响程度也是不同的。不同的净距既有隧道的竖向位移变化趋势基本相同，净距越大新建隧道的开挖对既有隧道的影响越小。当净距大于3D的时候影响很小了。
[Abstract]:With the continuous development of traffic, the traffic route becomes more and more complex, and it is not uncommon for the planned route to cross with the original traffic route. In the field of tunnel, there is bound to be the situation of piercing or going through the built tunnel in the field of tunnel. When the new tunnel passes through the existing tunnel at close range, the deformation of the soil layer and the additional internal force of the tunnel structure are caused by the disturbance of the soil caused by the excavation of the new tunnel. If the deformation of the existing tunnel structure exceeds the design limit, it will lead to the failure of the tunnel structure and affect the safe operation of the existing tunnel. At present, the research of crossing tunnel is mainly about the existing tunnel on the new tunnel, but the research on the underpass is relatively few. Many new problems can not be solved, and there is no corresponding specification for design and construction, and the standard can be followed. Therefore, only by fully understanding the influence of the new tunnel on the existing tunnel, can we determine the feasible design and construction scheme, and ensure the operation safety of the existing tunnel. On the basis of theoretical analysis, combined with the engineering example of Eryan Railway Tunnel on Zhongliangshan 1 Tunnel of Metro Line 6, the finite element numerical simulation and field monitoring data analysis are carried out in this paper. The influence of passing through the existing Eryan railway tunnel on the new tunnel is studied. The main contents are as follows: 1 from the theoretical analysis, we can know that geology, construction, structure, net distance and other factors directly or indirectly affect the safe operation of the existing railway tunnel when the new tunnel is excavated. (2) through the actual field monitoring, it can be seen that the vertical displacement of the existing railway tunnel caused by the excavation of the new tunnel shows the settlement before crossing, rising during crossing, and continuing to rise after crossing. The maximum settlement and uplift occur at the intersection of the new tunnel and the existing tunnel, and the change trend is about parabola. For the convergence deformation of the clearance of the existing tunnel, the mechanical shape of the supporting structure of the railway tunnel and the most direct parameters of the surrounding rock are reflected. The stability of the surrounding rock and the supporting structure can be known by the monitoring of the clearance convergence. Due to the unloading of the soil, the elastic-plastic deformation of the surrounding soil stress release occurs in the excavation of the new tunnel. The existing railway tunnel floats as a whole, and the whole tends to be stable after crossing. (3) through MIADAS-GTS numerical simulation, it can be seen that the vertical displacement of the existing Eryan railway tunnel increases with the excavation of the new tunnel. The change trend is parabola, and the change trend is basically the same under different working conditions, and the change quantity is slightly different. From the numerical simulation, it can be seen that the influence of the new No. 1 tunnel on the existing Eryan railway tunnel is mainly vertical displacement. (4) the influence degree of the net distance of the two cross tunnels on the existing tunnel is also different. The variation trend of vertical displacement of different net distance existing tunnels is basically the same, and the larger the net distance is, the smaller the influence of the excavation of new tunnels on the existing tunnels is. When the net distance is greater than 3D, the effect is very small.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4

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