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为了解黄土地区浅埋暗挖地铁隧道衬砌结构的受力特征,得出荷载在衬砌结构各部分中的分担比例,以西安地铁2号线实体工程为依托,开展了较大规模的现场测试工作,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及二次衬砌结构应力进行了研究。结果表明:在三连拱大断面地铁隧道中先开挖洞室初期支护各部位所受的围岩压力均大于后开挖洞室初期支护所承受的压力;左、右线中墙顶、底部初期支护承受的压力较大,表明隧道中隔墙承担了较大的上部土体荷载;初期支护与二次衬砌承受的荷载比例为52.81%和47.19%;二次衬砌混凝土基本受压,左、右中隔墙二次衬砌混凝土受压最大。在标准断面地铁隧道中左、右线墙脚位置初期支护与围岩之间接触压力较大,表明这两位置承受了大部分垂直压力;初期支护与二次衬砌承受的荷载比例为40%和60%;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 stress characteristics of the lining structure of shallow-buried metro tunnel in the loess area, the load sharing proportion in each part of the lining structure was obtained. Based on the solid engineering of Xi’an Metro Line 2, large-scale field test was carried out , The contact pressure between the surrounding rock and the initial support, the contact pressure between the initial support and the secondary lining and the stress of the secondary lining were studied. The results show that the pressure of surrounding rock subjected to the initial support of the first excavation cavern in the triple-arch large-section subway tunnel is greater than that of the initial support of the post-excavation cavern. , The pressure at the bottom of the initial support is large, indicating that the tunnel in the wall bear a large upper soil load; initial support and the secondary lining to bear the load ratio of 52.81% and 47.19%; secondary lining concrete basic Pressure, left and right in the second wall of the largest pressure of concrete lining. In the standard cross-section subway tunnel, the contact pressure between the initial support and surrounding rock in the position of the left and right lines at the foot of the subway line is relatively large, indicating that these two locations bear most of the vertical pressure; the load ratio of the initial support and the secondary lining is 40% And 60% respectively; the secondary lining concrete is basically compressed, the stress on the arch waist and above is larger, and the stress on the arch is smaller.