后河隧道宣汉端硐口段施工安全监测

Safety Monitoring and Measurement of Adit Construction on Xuanhan Side of Houhe Tunnel

后河川气东送管道过河隧道宣汉端为斜井,围岩软弱、破碎,采用短进尺、弱爆破开挖。为确保施工安全,采用了拱顶下沉、水平收敛、围岩与喷砼接触压力、锚杆轴力等监控手段。介绍了监测工作及实测数据及相应关系曲线。提出"弱爆破、短进尺、强支护、早封闭、勤监测"的原则,有效控制了围岩的变形。

The Houhe tunnel cross a river in Xuanhan side for Sichuan-to-east gas transmission pipelines is a inclined shaft,which the rock around is broken and weak,so the short footage and the loosing blasting were used to excavate.To ensure construction safety,the tunnel arch top settlement,horizontal convergence,contact pressure from wall rock with sprayed concrete,and axial stress of rock bolt were monitoring.The monitoring and monitored data with its relation curve are introduced.The proposed principle of loosing blasting,short footage,strong supporting,early closing and frequent monitoring could effectively control the deformation of wall rock.