浅埋大跨度隧道预应力锚杆锚固参数及支护设计研究  

Research on Anchorage Parameters and Support Design of Prestressed Anchors in Shallow Buried Large Span Tunnels

作　　者：殷小亮 张艳博 钟科 边文辉 杨贵均 王科学 姚旭龙 YIN Xiaoliang;ZHANG Yanbo;ZHONG Ke;BIAN Wenhui;YANG Guijun;WANG Kexue;YAO Xulong(China Railway Second Bureau Second Engineering Co.,Ltd.,Chengdu 610000,China;School of Mining Engineering,North China University of Science and Technology,Tangshan 063210,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]中铁二局第二工程有限公司,四川成都610000 [2]华北理工大学矿业工程学院,河北唐山063210 [3]深部岩土力学与地下工程国家重点实验室,北京100083 [4]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《金属矿山》2023年第2期58-66,共9页Metal Mine

基　　金：国家自然科学基金项目(编号:52074298)。

摘　　要：为明确浅埋大跨度隧道预应力锚杆的锚固参数及支护方案,为主动支护设计提供依据,以青岛地铁6号线华山一路站为例,采用理论分析、数值模拟、现场试验的研究手段,探究不同支护参数下的隧道施工力学特征。研究结果表明:(1)主动支护通过补偿径向应力σ3,降低切向应力σ1,改善了围岩的应力状态,锚杆与围岩形成共同承载体,提高了围岩的弹性模量、黏聚力、内摩擦角等力学性能;(2)锚固段长度越大,剪应力的分布范围呈增大趋势,随着张拉载荷的增加,剪应力峰值由锚固段端部逐渐向尾部转移,锚固长度为锚杆长度的40%~50%时锚固体的安全储备高;(3)锚杆的预应力在0~120 k N增加过程中,围岩的变形量与变形范围呈下降的趋势,拱部塑性区逐渐消失,拱脚与边墙的塑性区分布范围不断降低;随着锚杆的支护密度的提升,围岩的变形与应力均得到了一定程度的控制,但提升效果不显著;(4)从现场监测结果来看,主动支护结构稳定且安全储备高,其中围岩变形量在5.7 mm以内,格栅钢筋应力最高值为48.2 MPa,锚杆轴力由张拉至隧道开挖完成变化率仅为3.5%。In order to clarify the anchorage parameters and support scheme of pre-stressed anchors in shallow buried large span tunnels and provide a basis for active support design,the mechanical characteristics of tunnel construction under different support parameters are investigated by using theoretical analysis,numerical simulation and field tests,taking Huashan First Road Station of Qingdao Metro Line 6 as an example. The results show that:(1) Active support improves the stress state of the surrounding rock by compensating the radial stress and reducing the tangential stress,and the anchor rod and the surrounding rock form a common carrier together,which improves the mechanical properties of the surrounding rock such as elastic modulus,cohesion and internal friction angle.(2) The greater the length of anchorage section,the greater the distribution range of shear stress,with the increase of tensioning load,the peak shear stress is gradually transferred from the end of the anchorage section to the end,and the safety reserve of anchor solid is high when the anchorage length is 40% ~ 50% of the anchor rod length.(3) In the process of increasing the prestress of anchor rod from 0 to 120 k N,the deformation volume and deformation range of surrounding rock showed a decreasing trend,the plastic zone of arch gradually disappeared,and the distribution range of plastic zone of arch foot and side wall kept decreasing;as the support density of anchor rod increased,the deformation and stress of surrounding rock were controlled to some extent,but the enhancement effect was not significant.(4) From the field monitoring results,the active support structure is stable and has high safety reserve,in which the deformation of the surrounding rock is within 5. 7 mm,the highest value of grating reinforcement stress is 48. 2 MPa,and the change rate of anchor shaft force from tensioning to tunnel excavation completion is only 3. 5%.

关 键 词：隧道工程 预应力锚杆 锚固参数 支护设计 围岩变形 

分 类 号：U45[建筑科学—桥梁与隧道工程]