三维激光扫描技术在米仓山特长隧道施工中的可行性应用研究

巴陕高速米仓山特长隧道为我国目前在建最长公路隧道，全长约13.8km。利用三维激光扫描技术高速率、高精度获取对象表面三维坐标的优势，对米仓山隧道LJ2标段右线施工过程中的超欠挖、二衬厚度、掘进面爆破效果进行了检测，并对开挖断面围岩周边收敛和拱顶下沉进行了变形监测。结果表明，检测段隧道超挖区域比例占到81%，其中超挖0～20cm的占62%，欠挖0～10cm的为14%；二衬厚度选取不同里程、相同位置121个位置进行分析，最大厚度0.662m，最小0.456m，平均厚度0.564m；掘进面爆破深度约为3.048m，爆破方量为254.065m³；K54+030断面围岩周边收敛6d最大收敛变形量为9.5mm，拱顶下沉监测点6d最大变形量为5mm。

The Application of Three-dimensional Laser Scanning Technology in Micangshan Extra-long Tunnel Construction

Micangshan extra-long tunnel is the longest highway tunnel under construction in China with the total length of 13.8 km.3D laser scanning technology has the advantages of high-speed and high-precision to obtain the surface of the objects ' three-dimensional coordinates.The technology is used to monitoring and analyzing the tunnel' s overbreak-shortbreak, thickness of secondary lining, blasting effect of tunnel face,rock's deformation of circumjacent convergence and vault settlement.The results showed that tunnel's overbreak area is accounted for 81%,0~20 cm overbreak area is accounted for 62%,0~10 cm shortbreak area is accounted for 14%in the experimental section;the biggest,smallest and average thickness of secondary lining are 0.662,0.456 and 0.564 m respectively;blasting depth of tunnel face is about 3.048 m and the rock volume is 254.065 m3;maximum circumjacent convergence deformation and vault settlement are 9.5 mm and 5 mm in K54+030 section during 6 days.