沈阳地铁9号线吉汪段区间隧道施工稳定性研究及支护结构监测分析

发布时间：2018-09-10 10:46

【摘要】：随着我国新建地铁线路迅速增多的情况下,连接两条平行地铁隧道的渡线随之增多,再在渡线中部开设横通道,转入正洞施工时,需要在横通道处开口的部位较多,土体受力转换比较频繁,所以成为了结构的薄弱部位,对于开挖多个隧道如何保证隧道结构稳定是安全施工的必要条件,因此研究包含多个隧道的沈阳地铁9号线吉汪段区间隧道施工稳定性及支护结构监测具有非常重要的意义。论文以沈阳地铁9号线吉利湖街站～汪河路站区间隧道2号竖井横通道转正洞为工程背景,采用数值模拟和现场监测相结合的方法进行研究。该隧道是平行双线隧道,其中标准断面跨度为6.4m,大断面由于包含渡线部分,跨度达到了13.3m。论文通过FLAC3D软件对横通道转正洞的4条隧道进行数值模拟研究,并且通过模拟施工过程,对地表沉降、初期支护内力、支撑结构内力计算结果进行分析,研究施工过程隧道的稳定性。通过对施工过程的三维数值模型,得出隧道施工过程中的最不利位置,并且在这些部位的初期支护的钢格栅上布设钢筋应力计和光纤光栅传感器,对试验段支护结构内力和变形进行监测。通过现场监测分析在标准断面在开挖的过程中,支护结构钢格栅的钢筋应力的变化规律为：开挖1倍洞径时,初衬结构钢筋应力增长速度最快,之后增长速率明显下降,影响范围为5倍洞径,且隧道开挖过程中,初衬结构的受力过程是一个循环渐进的过程,并不是施加支护后支护结构立即承受围岩施加的所有力。同时利用标准断面的监测点分析相邻大断面开挖对标准断面的初衬内力的影响。在对大断面的初衬内力进行监测的同时,利用光纤光栅传感器对大断面的三个断面的钢格栅变形进行了监测,分析得出初衬以受压为主,最大压应力为4.14MPa,小于C30喷射混凝土的抗压强度,认为初衬结构满足承载力要求。
[Abstract]:With the rapid increase in the number of newly built subway lines in China, the number of crossing lines connecting two parallel subway tunnels will increase, and then a transverse passage will be opened in the middle of the crossing line. The change of soil force is frequent, so it becomes the weak part of the structure. How to ensure the stability of tunnel structure is the necessary condition of safe construction for excavation of multiple tunnels. Therefore, it is of great significance to study the construction stability and support structure monitoring of Jiwang section tunnel of Shenyang Metro Line 9 including multiple tunnels. In this paper, based on the engineering background of the No. 2 vertical tunnel between Geely Lake Street Station and Wanghe Road Station of Shenyang Metro Line 9, the method of combining numerical simulation and field monitoring is adopted. The tunnel is a parallel double-line tunnel, in which the span of standard section is 6.4 m, and the span of large section is 13.3 m because of the crossing line. In this paper, the numerical simulation of four tunnels in the normal tunnel of the transverse passage is carried out by FLAC3D software, and by simulating the construction process, the calculation results of the surface settlement, the initial supporting internal force and the internal force of the supporting structure are analyzed. The stability of tunnel during construction is studied. Through the three-dimensional numerical model of the construction process, the most unfavorable position in the tunnel construction process is obtained, and the reinforcement stress meter and the fiber Bragg grating sensor are arranged on the steel grille of the initial support in these parts. The internal force and deformation of support structure in test section are monitored. Through field monitoring and analysis, during the excavation process of standard section, the stress of steel grille of supporting structure is changed as follows: when the diameter of the first lining is doubled, the stress growth rate of the initial lining steel bar is the fastest, and then the growth rate is obviously decreased. The influence range is 5 times of the diameter of the tunnel, and the stress process of the initial lining structure is a cyclic and progressive process during the tunnel excavation, and not all the forces exerted by the surrounding rock immediately after the supporting structure is applied. At the same time, the influence of excavation of adjacent large section on the initial lining internal force of the standard section is analyzed by using the monitoring points of the standard section. While monitoring the initial lining internal force of the large section, the deformation of the steel grille of the three sections of the large section is monitored by using the fiber grating sensor, and it is concluded that the primary lining is mainly under pressure. The maximum compressive stress is 4.14 MPA, which is less than the compressive strength of C30 shotcrete.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U456.3;U231.3

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