有压隧洞管片衬砌在高水头荷载下的应力变形分析

Stress Deformation Analysis of Segment Lining in Pressure Tunnel under High Water Pressure

某拟建输水隧洞在III类围岩中采用开敞式TBM开挖,喷混凝土作为初期支护,钢筋混凝土管片作为衬砌,承担110m水头的内水压力和200m水头的外水压力,水荷载较大。在考虑管片之间及外包结构的接触关系、管片配筋和混凝土联合受力的条件下,采用有限元法模拟分析了管片衬砌在水荷载下的应力和变形特性,认为外水压力是管片衬砌设计的控制性荷载,从而提出了可供结构设计计算参考的管片模型简化处理方式。研究认为,在本文的围岩、支护、水荷载条件下,将钢筋混凝土管片作为隧洞衬砌是可行的。

A proposed water transfer tunnel will be excavated with tunnel boring machine （TBM） in the surrounding type-III rock. The shotcrete and reinforced concrete segment serve as the initial support and permanent liner, respectively. The consider- able internal and external water pressures are loaded on the liner, with the water head values of 110 m and 200 m, respectively. In this paper,in consideration of the contact relationship between segments, the contact relationship between segment and sur- rounding structure, and the cooperative working performance of reinforcement bars and concrete, the stress deformation charac- teristics of the liner under high water pressures are analyzed using the finite element method. The results showed that the exter- nal water pressure is the decisive load for the design of tunnel liner, and therefore a simplified model of segment liner design was proposed. The results suggested that it is feasible to use the reinforced concrete segment as tunnel lining under the conditions of the surrounding rock, support,and water pressure shown in the study.