目录1、工程概况..................................................................................................................22、负环拆除条件..........................................................................................................23、负环拆除的准备工作..............................................................................................44、负环拆除方法..........................................................................................................54.1负环拆除主要思想..........................................................................................54.2反力架的拆除..................................................................................................54.3负环管片的拆除..............................................................................................65、质量保证措施..........................................................................................................85.1质量保证组织结构...........................................................................................85.2质量保证具体措施...........................................................................................86、安全保证措施..........................................................................................................96.1安全保证组织结构..........................................................................................96.2安全保证具体措施...........................................................................................97、组织结构及劳动力................................................................................................108、拟投入主要施工设备............................................................................................109、应急预案................................................................................................................109.1应急救援小组.................................................................................................109.2应急救援小组职责.........................................................................................119.3负环拆除应急预案.........................................................................................119.4应急保障措施.................................................................................................13负环拆除专项施工方案1、工程概况天津地下直径线为单洞双线隧道，圆形隧道外轮廓为Ø11.6m，最小转弯半径R=600m曲线，隧道最大埋深达约43m，平均约20m。隧道内两端最大纵坡23‰，最小为3‰。管片外径为Ø11600mm，管片内径为Ø10600mm，分块为“8+1模式”的方式，即分块形式为6A(43.2º)+2B(43.2º)+K(14.4º)，一环内纵向采用25个等圆心角布置。管片采用通用双面楔形环管片，楔形量62mm，宽度为1800mm，厚度为500mm，钢筋混凝土衬砌采用C50高性能混凝土，抗渗等级为S12，在高精度钢模内制作成形。管片的拼装采用错缝拼装，管片接触面纵缝设凸凹榫，环缝不设凸凹榫，环与环之间以50根M30的纵向螺栓相连，块与块之间以2根M36的环向螺栓相连（整环共18个M36的环向螺栓）。本次拆除的负环共计7环。负环管片重量表：表1管片重量表管片编号A1A2A3A4A5A6B1B2K重量（t）8.928.928.98.98.98.98.98.932、负环拆除条件为了能够为后续工作提供空间，因而必须在掘进一定距离后将负环拆除，拆除负环后必须保证正环管片能够提供足够的摩擦力来支持盾构机的正常掘进。因此在负环拆除前，需对其受力进行分析以判断负环拆除的适时性。目前盾构机已掘进149m，完成管片拼装共77环（不包括负环管片）。管片土压...
