复杂条件下大断面隧道施工关键技术研究

Research on Key Technologies for Large Section Tunnel Construction under Complex Conditions

省某高速公路穿越了F6和F7断层破碎带,强富水段的洞身长度达到1480 m,洞身断面达到48.8 m2,IV级、V级围岩洞身长度占比越58%,隧道施工难度极大,在分析场区隧道围岩工程地质特征和工程重难点的基础上,针对强富水IV级、V级围岩,明确了钻爆参数和CD开挖工法;针对强富水条件穿越断层破碎带,提出超前全断面注浆帷幕法注浆参数,以对地下水进行止水和破碎岩体加固。结果表明,提出的超前全断面注浆帷幕法有效地改善了围岩力学性质和避免了地下水的突涌,提出的钻爆法施工参数保证了隧道的顺利贯通。

A certain highway in the province passed through the F6 and F7 fault fracture zones,with a tunnel length of 1480 m and a tunnel section of 48.8 m2 in the strong rich water section.The length of the IV and V grade surrounding rock tunnels accounts for 58%of the total length,making tunnel construction extremely difficult.Based on the analysis of the engineering geological characteristics and key and difficult points of the tunnel surrounding rock in the site,the drilling and blasting parameters and CD excavation method were clarified for the IV and V grade strong rich water surrounding rocks;Aiming at crossing fault fracture zones under strong water rich conditions,advanced full section grouting curtain method grouting parameters are proposed to seal groundwater and reinforce fractured rock masses.The results show that the proposed advanced full section grouting curtain method effectively improves the mechanical properties of the surrounding rock and avoids the sudden surge of groundwater.The proposed drilling and blasting method construction parameters ensure the smooth penetration of the tunnel.