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为了解黄土地区隧道围岩压力特征,得出荷载在衬砌结构中的分担比例,该文以三淅高速灵卢段西凹隧道为依托,选取3组不同围岩条件的测试断面,开展现场测试工作,对围岩与初期支护接触压力、初期支护与二次衬砌接触压力、锚杆轴力以及二衬混凝土应力等进行了研究。结果表明:黄土隧道墙角位置初期支护与围岩之间接触压力较大,表明两者承受大部分垂直压力;初期支护与二次衬砌接触压力随围岩土体强度降低而显著增大,二次衬砌在支护体系中的作用也随土体强度降低而凸显;黄土隧道锚杆对于围岩承载力没有明显效果,只有在围岩产生破坏时,系统锚杆通过约束作用使围岩承载力形成新的平衡或延缓结构破坏时间;二次衬砌混凝土基本受压,拱腰及以上位置应力较大,仰拱处应力较小。
In order to understand the pressure characteristics of the surrounding rock in the loess area, the load sharing proportion in the lining structure was obtained. Based on the Xikou tunnel in Linglu section of the Sanliu high speed zone, three test sections with different surrounding rock conditions were selected for on-site testing Work, contact pressure of surrounding rock and initial support, contact pressure between initial support and secondary lining, axial force of anchor bolt and concrete stress of the second lining were studied. The results show that the contact pressure between the initial support of the loess tunnel corner and the surrounding rock is large, indicating that both of them bear the most vertical pressure. The contact pressure between the initial support and the secondary lining increases with the decrease of the strength of the surrounding rock mass, The effect of the secondary lining in the supporting system is also obvious with the decrease of the strength of the soil; the anchor of the loess tunnel has no obvious effect on the bearing capacity of the surrounding rock. Only when the surrounding rock is damaged, the system rock bolt carries the surrounding rock by restraining action Force to form a new balance or delay structural damage time; the secondary lining concrete is basically compressed, arch waist and above the location of stress is larger, the stress at the arch is smaller.