软岩隧道支护参数优化研究

发布时间：2018-04-22 12:03

本文选题：软岩隧道 + 有限元　；参考：《兰州交通大学》2015年硕士论文

【摘要】：软岩大变形影响因素多,软岩隧道在支护参数方面不存在统一的、合理的设计经验可供直接借鉴。本文以牡绥线双丰隧道工程为研究对象,根据双丰隧道DK466+565里程段具体的软岩变形及支护结构特性,结合现场的监控量测试验,应用MIDAS及ANSYS有限元分析软件对该隧道支护参数进行优化研究,主要研究内容如下:(1)隧道施工过程中的监控量测。通过监控量测反馈的信息指导施工,对隧道的施工过程施行动态管理,在软弱围岩条件较差的地段加强监控,确保施工安全。(2)围岩参数的位移反分析。根据现场监控量测数据,用Excel软件根据最小二乘法原理对现场监测数据进行曲线拟合,预测位移最终值。然后,利用基于MATLAB的BP神经网络对围岩力学参数进行反分析计算,并验算反演结果的精度。(3)双丰隧道支护参数优化。结合双丰隧道具体的施工方法及支护设计,利用MIDAS-GTS有限元分析软件,采用地层—结构模型对影响围岩及支护结构稳定性的因素进行分析,主要优化内容包括锁脚锚管的长度、喷射混凝土的标号和厚度、钢拱架的型号和间距,以及利用ANSYS有限元分析软件,采用荷载—结构模型对双丰隧道二次衬砌不同厚度进行内力计算,通过对数值模拟的结果进行对比分析,对双丰隧道支护参数进行优化。研究结果表明:①锁脚锚管的长度越长,对控制围岩收敛变形和支护结构受力有益,综合改善的效果和受力来看,锁脚锚管取5.0m。②喷射混凝土的标号及厚度越大,围岩稳定性越好,支护应力也增大,其选择也要结合具体的围岩情况,最终选择30cm厚的C30喷射混凝土。③钢拱架间距对围岩稳定性及支护受力影响较大,钢拱架型号越大,间距越小,对围岩收敛控制效果越好,但相对支护应力越大,最终选择0.6m间距的I22a钢拱架。④根据各工况的数值模拟结果得到的围岩收敛变形值,结合监控量测数据,确定隧道施工的预留变形量为15cm。⑤二次衬砌结构厚度太小,关键部位的抗裂性能较差,在满足设计和运营的要求下选择50cm厚的二次衬砌。
[Abstract]:There are many factors affecting the large deformation of soft rock, and there is no uniform supporting parameter in soft rock tunnel. The reasonable design experience can be used for reference directly. Based on the soft rock deformation and support structure characteristics of the DK466 565 mileage section of Shuangfeng Tunnel, this paper takes Shuangfeng Tunnel Project of Musui Line as the research object, and combines the site monitoring and measurement test. MIDAS and ANSYS finite element analysis software are used to optimize the supporting parameters of the tunnel. The main contents of the research are as follows: 1) Monitoring and measurement in the construction process of the tunnel. Through the information of monitoring and measuring feedback to guide the construction, the dynamic management of the tunnel construction process is carried out, and the monitoring is strengthened in the section where the condition of the weak surrounding rock is poor, so as to ensure the construction safety and the displacement back analysis of the surrounding rock parameters. According to the field monitoring and measuring data, the field monitoring data are fitted by Excel software according to the principle of least square method, and the final displacement value is predicted. Then, BP neural network based on MATLAB is used to calculate the mechanical parameters of surrounding rock, and the accuracy of the inversion results is checked. 3) the support parameters of Shuangfeng tunnel are optimized. Combined with the concrete construction method and support design of Shuangfeng tunnel, the factors affecting the stability of surrounding rock and supporting structure are analyzed by using MIDAS-GTS finite element analysis software and the stratigraphic structure model. The main optimization contents include the length of anchor pipe with locking foot. The number and thickness of shotcrete, the type and spacing of steel arch frame, and the internal force of the secondary lining of Shuangfeng tunnel are calculated by using the ANSYS finite element analysis software and the load-structure model. By comparing and analyzing the results of numerical simulation, the support parameters of Shuangfeng tunnel are optimized. The research results show that the longer the length of the anchor pipe with the lock foot is, the more beneficial it is to control the convergence deformation of surrounding rock and the force of the supporting structure. In view of the comprehensive improvement effect and force, the bigger the label and thickness of the 5.0m.2 shotcrete is, the bigger the number and thickness of the lock foot anchor pipe is. The better the surrounding rock stability is, the greater the support stress is, and the selection of the support stress should be combined with the concrete surrounding rock condition. Finally, the 30cm thick C30 shotcrete steel arch spacing has a greater influence on the surrounding rock stability and the supporting force, and the larger the steel arch frame model is, The smaller the spacing, the better the control effect on surrounding rock convergence, but the greater the relative support stress, the final selection of 0.6 m spacing I22a steel arch frame .4 according to the numerical simulation results of various conditions of surrounding rock convergence deformation value, combined with monitoring measurement data, It is determined that the reserved deformation amount of tunnel construction is that the thickness of 15cm.5 secondary lining is too small and the crack resistance of key parts is poor. The secondary lining with 50cm thickness is chosen under the requirements of design and operation.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.7

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