摘要
隧道穿越断层角砾浅埋地层往往会引起掌子面溜塌、支护结构大变形、地表开裂等灾害,因此需要对支护参数与开挖方法进行优化设计。以西(宁)至成(都)铁路石林隧道进口浅埋断层角砾地层段为研究背景,采用数值模拟与现场实测方法,以隧道与地表变形控制为核心对隧道开挖方法进行优选。结果发现:与4分部CRD法、CD法、3台阶7步开挖法相比,6分部CRD法控制隧道与地表变形效果最优,其中缩小开挖面积与设置临时支护对控制隧道与地表变形效果较好;6分部CRD法开挖时,前4部隧道变形占比为67.5%~68.9%,后2部隧道变形占比仍有31.1%~32.5%,直至钢拱架封闭隧道变形才趋于收敛;地表无裂缝,沉降在30 mm以内,均符合高斯分布,反弯点位于30 m附近,沉降槽宽度为60 m左右。
Tunneling passing through shallow-buried strata of fault breccia often leads to disasters such as tunnel face collapse,significant deformation of support structures,and surface cracking.Therefore,it is necessary to optimize support parameters and the design of excavation methods.Taking the shallow-buried fault breccia stratum section at the entrance of the Shilin Tunnel of the Xining to Chengdu Railway as example,this paper uses numerical simulation and field measurement methods to optimize the tunnel excavation method,focusing on controlling the deformation of both the tunnel and the ground surface.The results indicate that the 6-step CRD method exhibits the best control over tunnel and ground surface deformation compared to the 4-step CRD method,CD method,and 3-stage 7-step excavation method.Specifically,reducing the excavation area and implementing temporary supports are effective in controlling deformation.During the excavation using the 6-step CRD method,the deformation of the first four steps of the tunnel accounts for 67.5%to 68.9%,while the deformation of the last two steps still accounts for 31.1%to 32.5%.The tunnel deformation continues to converge only after the steel arch closure.There are no cracks on the surface,and the settlement remains within 30 mm,both of which conform to a Gaussian distribution.The inflection point is located around 30 m,with the width of the settlement trough measuring approximately 60 m.
作者
田振宇
TIAN Zhenyu(Lanzhou-Xinjiang Railway Gansu-Qinghai Co.,Ltd.,Lanzhou Gansu 730030,China)
出处
《中国铁路》
北大核心
2025年第8期45-52,共8页
China Railway
基金
中铁第一勘察设计院集团有限公司科研开发项目(2024-C39)
兰新铁路甘青有限公司技术合作开发合同(GQGC2025-002)。
关键词
铁路隧道
断层角砾
开挖方法
变形控制
施工方法优化
railway tunnel
fault breccia
excavation method
deformation control
construction method optimization
作者简介
田振宇(1978-),男,高级工程师。E-mail:250179606@qq.com。
