摘要
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 precisely understand the mechanical characteristics for secondary linings of shallow excavation metro tunnels in loess region,large scale field tests are conducted at Xi＇an metro line No.2 site.The contacting pressure on the surrounding rock and the initial support system,contacting pressure on the initial supports and secondary linings and the stress of the secondary linings are monitored.The test results indicate that the surrounding rock pressures of each part in the initial support in earlier excavation chamber are larger than those in later excavation chamber of three-arched metro tunnel,and the pressures at the top and bottom parts of left and right center pillars are the largest due to large load at the upper part.The loading ratio is 52.81% and 47.19% respectively for the initial supports and secondary linings.The stress of the secondary linings is pressure stress,which is the largest at the left and right center pillars.The surrounding rock pressures in the wall foot at the left and right on standard section metro tunnel are the largest due to large load at the upper part.The loading ratio is 40% and 60% respectively for the initial supports and secondary linings.The stress of the secondary lining is pressure stress,which is the largest on the upper arch loin and is smaller on the inverted arch.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2011年第8期1167-1172,共6页
Chinese Journal of Geotechnical Engineering
关键词
黄土地铁隧道
浅埋暗挖
衬砌
现场测试
受力特征
loess metro tunnel
shallow excavation
lining
field test
mechanical characteristics
