长大隧道控制网分段建网方案对比分析

Comparison and Analysis of Control Network Construction Schemes in Sections for Long Tunnels

由于地质条件和施工工期等原因,在长大隧道中难以保证隧道在预期内贯通,导致隧道进出口的CPI控制点无法同时为洞内CPII控制网提供约束而进行测量,因此需要对隧道洞内CPII控制网分段测量。本文以某实测隧道洞内CPII控制网分两段建网为例,对数据整合处理,将隧道数据分为整网、分段、整网含斜井三种建网方案对比分析。以点位精度、坐标之差、偏垂距之差进行对比,实验表明长大隧道洞内CPII控制网分段测量是可行的,其中分段方案的精度最优。同时,应该充分地利用斜井口的CPI控制点来约束横向偏差,保证CPII控制网能够达到相应的精度和要求。

Due to geological conditions,construction period and other reasons,it is difficult to ensure that the tunnel is connected in the expected time in the long tunnel,resulting in that the CPI control points at the tunnel entrance and exit cannot simultaneously provide constraints for the CPII control network in the tunnel for measurement,so it is necessary to measure the CPII control network in the tunnel in sections.In this paper,the CPII control network in a measured tunnel is divided into two sections as an example,and the tunnel data is divided into three network construction schemes:the whole network,the section,and the whole network with inclined shaft.Compared with the point accuracy,the difference of coordinates and the difference of offset and vertical distance,the experiment shows that the segmented measurement of CPII control network in the long tunnel is feasible,and the segmented scheme has the best accuracy.At the same time,the CPI control points of the inclined wellhead should be fully used to constrain the lateral deviation,so as to ensure that the CPII control network can meet the corresponding accuracy and requirements.