拉林铁路巴玉隧道强岩爆段初始应力场反演

Initial Geostress Inversion in Bayu Tunnel with Intensive Rockburst in Nyingchi-Lhasa Railway

拉林铁路巴玉隧道开挖过程中岩爆频发,严重影响了工程安全.基于实测的巴玉隧道开挖过程中地应力测试成果,采用全局优化随机搜索的应力边界试算方法,反演分析了巴玉隧道强岩爆段初始应力场.研究结果表明:巴玉隧道强岩爆段最大主应力垂直于隧道走向,主应力与埋深呈正相关且最大主应力最大值可达52.4 MPa.二次开挖应力分布特征表明巴玉隧道开挖过程中拱腰极易发生岩爆,拱顶和边墙岩爆发生的可能性相对较小.研究结果可为川藏铁路岩爆发生机理和防治研究提供参考.

Rockbursts occur frequently during the excavation of Bayu Tunnel in Nyingehi—Lhasa Railway,influencing the engineering safety seriously.Based on the in-situ geostress testing results,the trial calculation method of stress boundary is used to jnverse the initial stress of tunnel sections with intensive rockburst by overall random search.The study shows that the maximum principal stress is perpendicular to the tunnel direction.The principal stress and buried depth are positive correlation and its maximum value reaches 52.4 MPa.The feature of secondary excavation stress indicates that the spandrel of Bayu Tunnel has the high possibility of rockbursts,while the rockbursts probability of vault and side wall is relatively small.The research could be a reference for studying the occurrence mechanism and control of rockbursts during the construction of Sichuan—Tibet Railway.