青藏高原隧道温度场分布特性及衬砌结构稳定影响研究

发布时间：2018-11-19 22:28

【摘要】：本文依托共和至玉树公路的鄂拉山隧道工程实例,采用基于Mohr-Coulomb屈服准则的理想弹塑性模型作为岩土体本构,展开了应力场—温度场耦合数值模拟,对青藏高原严酷环境条件下隧道的温度场与衬砌结构稳定影响因素展开了系列研究。论文分析了考虑多影响因素下的各因素影响程度,并得到了系列结论,对寒区隧道的建设具有一定的指导意义。论文首先进行了隧道温度场数值模拟研究,基于不同纵深隧道的有限元模型,在多工况下分析了围岩和衬砌的温度场。结果表明:衬砌底部中轴线最高温度与最低温度差值随纵深发展不断增大,温度变化速率先快后慢,逐渐趋向于平稳,隧道进口约前40m变化较快,且衬砌底部温度明显高于顶部。在此基础上,进行了隧道变形与应力数值模拟研究,在多工况下分析了不同衬砌材料的主应力和各部位位移。结果表明:衬砌的拱肩及拱脚位置容易产生应力集中和最大位移量。在考虑温度应力后,应力值大幅升高且以拉应力为主,而位移分布整体上保持不变。最后开展了隧道影响因素研究,计算了重要参数下隧道衬砌温度、应力和位移分布的变化规律,探讨了影响隧道衬砌性能的主要因素。结果表明:对复合衬砌结构稳定影响最大因素为温差,其次为线膨胀系数和接触面摩擦系数。
[Abstract]:In this paper, based on the engineering example of Erashan Tunnel of Gonghe to Yushu Highway, the ideal elastic-plastic model based on Mohr-Coulomb yield criterion is used as the constitutive model of rock and soil, and the coupled numerical simulation of stress field and temperature field is carried out. The influence factors of tunnel temperature field and lining structure stability under severe environmental conditions in Qinghai-Xizang Plateau are studied. The paper analyzes the influence degree of each factor under the consideration of many factors, and obtains a series of conclusions, which has certain guiding significance for the construction of tunnel in cold area. Firstly, the numerical simulation of tunnel temperature field is carried out. Based on the finite element model of different depth tunnels, the temperature field of surrounding rock and lining is analyzed under various working conditions. The results show that the difference between the maximum temperature and the lowest temperature in the central axis of the bottom of the lining increases with the development of the depth, the temperature change rate is first fast and then slow, and gradually tends to be stable, and the first 40 m before the entrance of the tunnel changes rapidly. The temperature at the bottom of the lining is obviously higher than that at the top. On this basis, the numerical simulation of tunnel deformation and stress is carried out, and the principal stress and displacement of different lining materials are analyzed under various working conditions. The results show that the stress concentration and maximum displacement are easily produced in the arch shoulder and arch foot position of lining. After considering the temperature stress, the stress value increases greatly and the tensile stress is the main one, while the displacement distribution remains the same as a whole. Finally, the influence factors of tunnel are studied, and the variation law of tunnel lining temperature, stress and displacement distribution under important parameters are calculated, and the main factors affecting tunnel lining performance are discussed. The results show that the temperature difference is the most important factor affecting the stability of the composite lining structure, followed by the linear expansion coefficient and the friction coefficient of the contact surface.
【学位授予单位】：青海大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451

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