兰渝铁路木寨岭隧道高地应力软岩施工变形控制研究

发布时间：2018-03-31 17:28

本文选题：高地应力　切入点：软岩　出处：《兰州交通大学》2014年硕士论文

【摘要】：新建兰渝铁路是我国重点支撑性基础设施项目，论文以新建兰渝铁路木寨岭隧道为研究背景，结合木寨岭隧道现场施工方法、监控量测实测项目，运用数值模拟方法进行高地应力软岩大变形控制技术方面的研究。论文针对木寨岭隧道施工现场因大变形产生的拱架变形、二衬开裂等问题开展了以下研究：（1）论文根据木寨岭隧道的工程地质情况，结合室内土工试验的试验结果，选取模型材料计算参数；在隧道施工现场选取典型断面，监测断面开挖后围岩的变形情况，并对监测数据进行回归分析，得出木寨岭隧道高地应力大变形软岩的变化规律。（2）论文运用有限元软件MIDAS-GTS对木寨岭隧道三台阶法施工进行数值模拟，研究隧道开挖过程中围岩随开挖步和掌子面相对位置变化引起的变形所占总变形的比例，得出控制大变形的技术措施，进一步研究隧道塑性区范围、侧压力系数对支护结构变形、应力的影响，提出支护方式的优化措施。（3）通过模拟有大拱脚二衬和无大拱脚二衬施工，，研究在两种情况下隧道围岩的变形、受力特点，验证二衬浇筑技术改进的合理性和有效性，提出隧道二衬施工的优化措施。（4）通过对木寨岭隧道CRD法施工过程的数值分析，对比三台阶法施工的围岩受力变形情况，为木寨岭隧道施工方法的选取提出建设性意见。论文得出了如下研究成果：（1）通过对木寨岭隧道监测数据的回归分析处理验证了现场施工方法、支护形式的合理性，能够较准确地判断二衬施做得合理时机，并为必要时及时调整支护结构提供有力依据。（2）数值模拟结果表明收敛曲线开挖面前方先行变形占总变形的32.8%，掌子面变形占总变形的54.9%，掌子面后方变形占总变形的12.3%，软弱围岩隧道施工中加强拱部超前支护对控制大变形有重要作用，由此提出有效的高地应力软岩隧道大变形控制技术。（3）通过对有大拱脚二衬和无大拱脚二衬数值模拟，计算结果表明有大拱脚二衬围岩拱顶下沉值比无大拱脚二衬围岩减小36%，有大拱脚二衬围岩水平收敛值比无大拱脚二衬减小38%，表明与无大拱脚二衬相比，有大拱脚二衬可以明显减小围岩拱顶下沉值、水平收敛值。（4）运用有限元软件对木寨岭隧道CRD法进行数值模拟，计算结果表明：与三台阶法相比，CRD法施工围岩拱顶沉降减少10%，水平收敛减少12%，应力变化曲线更平缓，变化幅度更小，支护结构更合理。综上所述，论文结合木寨岭隧道现场监测数据，进行了大量数值模拟计算，验证了现场施工方法的合理性，并提出了更合理的大变形控制技术及优化措施，为木寨岭隧道及类似隧道的设计施工提出了有效的建议，产生了较好的经济效益和社会效益。
[Abstract]:The newly built Lanzhou-Chongqing Railway is an important supporting infrastructure project in China. This paper takes the Muzhai Ridge Tunnel of the Lanzhou-Chongqing Railway as the research background, combined with the field construction method of the Muzhailing Tunnel, monitoring and measuring the actual measurement project.Numerical simulation method is used to study the control technology of large deformation of soft rock with high ground stress.Aiming at the problems of arch frame deformation and second lining cracking caused by large deformation in the construction site of Muzhailing tunnel, this paper has carried out the following research:1) according to the engineering geology of Muzhailing tunnel and the test result of indoor geotechnical test, the model material parameters are selected, the typical section is selected in the tunnel construction site, and the deformation of surrounding rock after excavation is monitored.By regression analysis of monitoring data, the variation law of soft rock with high ground stress and large deformation in Muzhailing tunnel is obtained.In this paper, the numerical simulation of the three step method construction of Muzhailing tunnel is carried out by using the finite element software MIDAS-GTS, and the proportion of the deformation caused by the change of the surrounding rock with the relative position of the excavation step and the face of the face in the tunnel excavation is studied.The technical measures to control the large deformation are obtained, and the influence of the range of the plastic zone of the tunnel and the coefficient of lateral pressure on the deformation and stress of the supporting structure is further studied, and the optimization measures of the supporting mode are put forward.3) by simulating the construction with and without large arch foot, the deformation and stress characteristics of surrounding rock in tunnel are studied, the rationality and validity of the improvement of second lining pouring technology are verified, and the optimization measures of tunnel construction are put forward.4) through the numerical analysis of the construction process of the CRD method of Muzhailing tunnel, the stress and deformation of surrounding rock in the construction of the three classes method are compared, and the constructive suggestions for the selection of the construction method of the tunnel are put forward.The research results are as follows:1) through the regression analysis of the monitoring data of Muzhailing tunnel, it is proved that the construction method is reasonable and the support form is reasonable, which can judge the reasonable time of the second lining construction accurately, and provide a strong basis for adjusting the supporting structure in time when necessary.The numerical simulation results show that the forward deformation of convergence curve is 32.8% of the total deformation, that of palm surface is 54.9%, that of the rear face of palm surface is 12.3% of the total deformation, and that the advance support of arch part should be strengthened in the construction of soft surrounding rock tunnel.Controlling large deformation plays an important role.Therefore, an effective control technique for large deformation of soft rock tunnel with high ground stress is put forward.(3) by numerical simulation of two linings with and without large arches,The calculation results show that the settlement value of surrounding rock arch with large arch foot is 36 times smaller than that without large arch foot, and the horizontal convergence value of surrounding rock with large arch foot is 38 less than that with no large arch foot, which shows that compared with the second wall rock with no large arch foot, the horizontal convergence value of surrounding rock with large arch foot is reduced by 38 percent compared with that without large arch foot.The second liner with large arch foot can obviously reduce the value of the wall rock arch roof subsidence and the horizontal convergence value.4) the numerical simulation of CRD method for Muzhailing tunnel is carried out by using finite element software. The results show that compared with the three class method, the settlement of surrounding rock arch is reduced by 10%, the horizontal convergence is reduced by 12%, the stress change curve is more gentle and the change range is smaller than that of the three class method.The supporting structure is more reasonable.To sum up, the paper combines the monitoring data of Muzhailing tunnel, carries out a large number of numerical simulation calculations, verifies the rationality of the field construction method, and puts forward more reasonable large deformation control technology and optimization measures.Effective suggestions for the design and construction of Muzhailing tunnel and similar tunnels are put forward, and good economic and social benefits are obtained.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4

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