铁道标准设计2025，Vol.69Issue(10)：126-132,7.DOI:10.13238/j.issn.1004-2954.202506300005
锚索在超大跨隧道中的作用机理及其设计方法
Mechanisms of Action and Design Methods of Anchor Cables in Super-Large-Span Tunnels
摘要
Abstract
To address the challenge of stability control of surrounding rock in super-large-span tunnels with a span ≥ 18 m,the mechanism of action and design method of prestressed anchor cables were systematically investigated,taking the Badaling Tunnel of the Beijing-Zhangjiakou high-speed railway as the engineering background.The results showed that in super-large-span tunnels,the bending moment of the second lining caused by self-weight increased significantly,leading to a reduction in effective bearing capacity.Therefore,the traditional passive support concept should be abandoned,and an active support system with prestressed bolts and anchor cables as the core should be adopted,transforming the surrounding rock into the main bearing structure and constructing a self-bearing system of the surrounding rock by forming shallow and deep bearing arches.Anchor cables manifested through five mechanisms of action in support:suspension,span reduction,confining pressure,improvement,and arching.Suspension required the prestress to be greater than the self-weight of the arch ring or the net weight of unstable blocks.Span reduction reduced the equivalent span of the surrounding rock from the tunnel span to the anchor cable spacing,significantly improving the stress state.Confining pressure enabled the rock mass to be in a three-way stress state.Grouting improvement and arching further enhanced the integrity and overall stability of the surrounding rock.The design of anchor cables should establish corresponding mechanical models based on each function,and the tensile locking value should consider the prestress increment caused by subsequent construction deformation to prevent it from exceeding the pull-out strength.A joint support design method of"one spray and two anchors"was proposed,and a safety factor evaluation model based on the bearing arch theory was established,forming a full-chain solution from mechanism analysis and design calculation to engineering practice.This is of great significance for improving the scientific nature,safety,and economy of support design for super-large-span tunnels.关键词
铁路隧道/设计方法/作用机理/预应力锚索/超大跨隧道/承载拱/作用机理/支护设计Key words
railway tunnel/design method/mechanism of action/prestressed anchor cable/super-large-span tunnel/bearing arch/support design分类
交通运输引用本文复制引用
刘建友,吕刚,赵勇,岳岭,刘方..锚索在超大跨隧道中的作用机理及其设计方法[J].铁道标准设计,2025,69(10):126-132,7.基金项目
中国国家铁路集团有限公司科技研究开发计划(K2023G045) （K2023G045）
