土压平衡盾构近距离下穿既有地铁无配筋二次衬砌大断面隧道施工技术

为确保盾构近距离下穿北京地铁1号线复兴门—西单区间无配筋二次衬砌大断面隧道期间结构、设施稳定,变形可控,列车运营不受影响,结合工程实际调研情况,根据穿越区段隧道状态评定为3级(较重病害)的结果,提出盾构近距离下穿大断面素混凝土二次衬砌隧道关键施工技术,主要包括1号线结构病害治理、粘贴芳纶布、钢板带加固,1号线洞外注浆加固穿越段地层,盾构掘进参数控制,并辅以监控量测技术。结果表明:1)1号线隧道无配筋结构采用芳纶布、钢板带等加固技术,强度、刚度、稳定性等均满足要求,未发生结构开裂及掉块情况。2)盾构与既有线之间采用施工导洞密贴穿越1号线后两侧注浆,能有效减少钻孔长度,提高钻孔及注浆的精确性,同时密贴导洞为1号线提供有效支顶作用;另外,导洞下穿段设置千斤顶支顶措施,可提高沉降控制效果。3)设置试验段、优化掘进参数、充填克泥效、同步及二次注浆等措施,在沉降控制中起到了十分积极的作用,减小了对既有线和列车的影响,保证了施工安全和质量。

雁门关隧道应急停车带二次衬砌施工技术

雁门关隧道应急停车带二次衬砌采用钢拱架与小模板组合的方式 。

浅谈大断面针梁模板衬砌混凝土底板气泡的防治办法

蒲石河抽水蓄能电站尾水隧洞混凝土衬砌施工中摸索出一套针对特大断面针梁模板衬砌混凝土底板气泡的防治办法。

Researches on the key technology and equipment for rapid construction of long tunnels with large section

Excavation and lining are two main important tasks in tunnel construction. Conventional sequential operations may not be appropriate due to time limit for a project and the high cost of construction. The authors developed a new mode of tunnel construction that excavation and lining can be operated simultaneously. The new mode of tunnel construction has been successfully applied to Dahuofang Water Conveyance Project in Liaoning Province. This paper makes a comparison of Main Beam TBMs and Double Shield TBMs used in Dahuofang Water Conveyance Project, and the features of Full-ring Inner-through Lining Shutter Jumbo which solves the problem of interference between excavation and lining.