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高岩温热害问题是深埋隧道面临的难点问题之一。高岩温不仅会恶化施工环境、影响施工材料的选择和混凝土的耐久性等,高温带来的温度应力还会引起衬砌的开裂和围岩的变形等。为分析高岩温作用下隧道结构和围岩的温度场、应力场分布规律,根据简化的理论模型,建立了隧道的热传导方程和平衡方程,并利用量纲归一化和微分方程级数求解的方法得到了隧道结构和围岩的温度场、位移场、应力场的解析解。以典型的高原地热隧道-拉日铁路吉沃希嘎隧道为例进行详细地分析。研究发现:隔热层能有效地阻隔热量传递,减少围岩热量的散失;铺设隔热层后,初衬的温度升高;增加隔热层厚度可以加强隔热效果,但隔热层厚度的选择要综合考虑初衬温度以及材料性能变化的影响。
One of the difficult problems facing deep tunnels is the high temperature rock thermal damage problem. High temperature will not only worsen the construction environment, affect the choice of construction materials and concrete durability, temperature stress caused by high temperature can also cause lining cracking and deformation of surrounding rock. In order to analyze the distribution of temperature field and stress field of tunnel structure and surrounding rock under high rock temperature, according to the simplified theoretical model, the tunnel heat conduction equation and equilibrium equation are established. By using the normalized dimension and the differential equation series The analytical solutions of temperature field, displacement field and stress field of tunnel structure and surrounding rock are obtained. Taking a typical plateau geothermal tunnel - Joshihiga tunnel on the Riyadh railway as an example, this paper analyzes in detail. It is found that the heat insulation layer can effectively block the heat transfer and reduce the heat dissipation of the surrounding rock. After the heat insulation layer is laid, the temperature of the initial lining rises. Increasing the thickness of the heat insulation layer can enhance the heat insulation effect. However, the thickness of the heat insulation layer Choose to consider the initial lining temperature and the impact of changes in material properties.