黄土公路隧道初期支护优化设计研究

发布时间：2018-04-19 13:07

本文选题：黄土公路隧道 + 初期支护　；参考：《长安大学》2014年硕士论文

【摘要】：随着山区高速公路的建设和西部地区经济的高速发展，穿越黄土地区的公路隧道日益增多。由于黄土特殊的工程性质和隧道工程的复杂性，通过工程类比法修建的黄土隧道在施工和运营期间出现了许多病害，对黄土隧道的支护结构优化设计需要进行深入研究。本文结合大量已建的黄土隧道，通过资料调研、理论分析和数值模拟的方法对黄土公路隧道的初期支护体系提出采用钢管混凝土代替钢拱架，增加初期支护厚度，采用模筑混凝土代替喷射混凝土的优化设计思想，采用MIDAS/GTS大型有限元软件建立平面有限元模型，对钢管的型式和尺寸进行正交试验，分析初期支护中不同钢管尺寸对围岩和隧道的影响性状，并结合工程经济性推荐钢管的型式和尺寸。对比原设计和优化设计假定抗力法计算的初期支护安全系数，并用有限元模拟原设计和优化设计的支护效果，结果表明优化设计结构的安全性和围岩的位移和塑性区都得到了有效的控制。采用MIDAS/GTS有限元软件建立隧道开挖支护完成后浸水模型，对浸水条件下新型支护结构的安全性进行评价。结果表明：浸水降低了围岩的自承能力，使围岩整体产生了竖向位移，浸水使围岩应力再次重新分布，隧道周边出现了应力集中，浸水后围岩塑性区的面积和最大塑性应变值也都有所增大。对于支护结构，浸水后仰拱的轴力增加较大，其他部位的轴力和弯矩受浸水影响较小。浸水对优化设计的影响幅度大于原设计，，但是优化设计的支护效果仍优于原设计。
[Abstract]:With the construction of mountain highway and the rapid development of economy in western China, the number of highway tunnels passing through loess area is increasing day by day.Because of the special engineering properties of loess and the complexity of tunnel engineering, many diseases appear in the construction and operation of loess tunnel built by engineering analogy method. The optimization design of supporting structure of loess tunnel needs to be deeply studied.Combined with a large number of loess tunnels that have been built, through the investigation of data, theoretical analysis and numerical simulation method, this paper puts forward to the initial supporting system of loess highway tunnel using concrete filled steel tube instead of steel arch frame to increase the initial support thickness.In this paper, the optimum design idea of replacing shotcrete with formwork concrete is adopted, and the plane finite element model is established by using MIDAS/GTS software, and the type and size of steel pipe are tested by orthogonal test.This paper analyzes the influence of different steel pipe size on surrounding rock and tunnel in initial support, and recommends the type and size of steel pipe in combination with engineering economy.Compared with the initial support safety factor calculated by the original design and the optimization design assumed resistance method, the support effect of the original design and the optimization design is simulated by the finite element method.The results show that the security of the optimized design structure and the displacement and plastic zone of surrounding rock are effectively controlled.The MIDAS/GTS finite element software was used to establish the post-immersion model of tunnel excavation support, and the safety of the new support structure was evaluated under the condition of flooding.The results show that soaking reduces the self-supporting capacity of surrounding rock, causes vertical displacement of surrounding rock, redistributes the stress of surrounding rock, and presents stress concentration around tunnel.After immersion, the area of plastic zone and the maximum plastic strain value of surrounding rock are also increased.For the support structure, the axial force of the inverted arch increases greatly after immersion, and the axial force and bending moment of other parts are less affected by the immersion.The influence of water immersion on the optimal design is larger than that of the original design, but the support effect of the optimal design is still better than that of the original design.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.7

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