分段施测隧道内CPⅡ控制网关键技术探讨

Discussion on the Key Technologies of CPⅡControl Network in Tunnel by Segments Survey

长大隧道施工过程中,部分关键施工段落因地质情况变化,开挖面不能按期贯通,严重影响全线铺轨工期。为缓解工期压力,通过制定专项测量方案,将已贯通段落分段测设隧道内CPⅡ平面控制网;在隧道未全部贯通的情况下,先施工隧道洞内无砟轨道,以节约施工时间。针对分段施测洞内CPⅡ平面控制网观测条件差、各分段之间的衔接误差难以调整以及可能引起隧道净空侵界等难点,从分段施测隧道洞内CPⅡ平面控制网的施工风险、施测基本条件,总结提高分段施测隧道洞内CPⅡ平面控制网精度的关键技术措施等方面展开分析,以期为同类工程施工提供借鉴。

During the construction of a long and large tunnel,due to changes in geological conditions,the excavation surface of some key construction sections could not be penetrated as scheduled,which seriously affected the track laying period of the whole line.In order to alleviate the pressure of the construction period,the tunnel was penetrated into the CPⅡplane control network in sections with the development of a special survey plan.In the case that the tunnel was not fully penetrated,the ballastless track in the tunnel was constructed first to save construction time.In order to solve the problems including poor observation conditions of the CPⅡnetwork,difficult adjustments in terms of the connection errors between the sections,and errors of the tunnel clearance obstacle,this research analyzed the construction risk of the CPⅡnetwork in the tunnel as well as the basic conditions of the construction survey,summarized the key technical measures and provided a reference for similar projects.