为探讨隧道结构在低真空复杂环境下的适用性,在搭建低真空管道系统试验平台的基础上,对隧道管道结构在低真空复杂工况下的力学行为及密封性能进行物理模拟试验研究,得出以下结论: 1)抽真空使管壁整体受压,且以环向受力为主,外壁应力在 1 MPa 以内,受管内抽真空气流影响,内壁应变大于外壁且分布不均匀; 2)管壁所受轴力为60~200 kN,弯矩最大值为1. 4 kN·m, 处于大偏心受压状态; 3)管内温度越高,漏气速率越快,试验系统的密封薄弱点在两侧预埋钢板与管道混凝土结合处; 4)低真空引起的结构受力变形整体较小,为保证密封性能,真空管道运输结构采用现有的隧道拼装式管片结构时建议加整体内衬。

The physical simulation experiment for mechanical behavior and sealing performance of tunnel structure under low vacuum condition is conducted base on the low vacuum pipe system platform, so as to explore the feasibility of tunnel structure in complex low vacuum environment. Some conclusions are drawn as follows: (1) The whole pipe wall is pressured due to annular force by vacuuming; the stress of outer wall is below 1 MPa; the stress of inner wall is greater than that of outer wall and is uneven due to the influence of inner airflow caused by vacuuming. (2) The axial force of pipe is between 60 kN and 200 kN, and the maximum bending moment is 1. 4 kN·m, which indicates that the pipe is in a state of large eccentric compression. (3) The higher the temperature in the pipe, the larger the leakage rate; the weak sealing points locate at the junction of embedded steel plate and concrete on both sides of pipe. (4) The structural deformation induced by low vacuum is small; in order to guarantee the sealing performance, the integral lining is recommended when the assembled tunnel segment structure is used in low vacuum pipe structure.