构造应力场中的软岩客运专线双线隧道稳定性研究  

Study of stability of two-lane soft rock tunnel for high-speed passenger railway in tectonic geo-stress

作　　者：何本国[1] 张志强[1] 何川[1] 王俊奇[2] 

机构地区：[1]西南交通大学土木工程学院,成都610031 [2]华北电力大学可再生能源学院,北京102206

出　　处：《岩土力学》2012年第5期1535-1541,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51078318);新世纪优秀人才支持计划(No.NCET-10-0667);中央高校基本科研业务费专项资金科技创新项目(No.SWJTU09CX006);国家重点基础研究发展计划(973计划)资助项目(No.2010CB732105)

摘　　要：以铁道部250 km/h客运专线标准断面双线隧道为对象,依托木寨岭高地应力软岩隧道工程,研究构造应力场条件下隧道变形特性、能量积聚、力学响应及塑性区规律。水平大主应力平行隧道轴线时,高能集中区和塑性区主要集中于边墙,掌子面前方围岩能量密度较小,掌子面挤出变形较大;水平大主应力垂直轴线时,高能集中区和塑性区主要分布在拱顶、仰拱及掌子面,掌子面前方围岩能量密度较大,挤压变形较小。研究表明:掌子面前方待开挖核心土体表现能量-位移正交性,而目前采用简单的挤出变形来判别掌子面稳定性,其合理性值得进一步商榷;规范给出"最大水平主应力与隧道轴线平行或小角度相交设计原则",并不是对所有高地应力场都适用;锚杆在开挖初期有效促进临时"承载拱"的形成,使"压力拱"偏移至隧道轮廓附近,成为施工初期稳定的关键;锚杆降低边墙深部岩体切向应力峰值,随着掌子面推进,拱效应不断向深部岩体移动,形成动态压力拱。By taking on standard cross section used for two-lane soft rock tunnel on high-speed passenger railway for 250 km/h,Muzhai Mountain soft rock tunnel is cited here.Meanwhile,energy accumulation,deformation,mechanical response and plastic zone are developed to study stability of tunnel in different characteristics of geostress field.When the horizontal maximum principal stress is parallel to the tunnel axis,high energy and plastic zones occur at wall of tunnel mostly.Energy density ahead of working face is smaller;and squeezing deformation of working face is larger.However,when the horizontal maximum principal stress is perpendicular to the axis,high energy and plastic zones distribute at crown and invert of tunnel,ahead of working face.The energy density is larger and the squeezing deformation is smaller ahead of working face.Consequently,the conclusions can be drawn as follows： there is mechanical behavior of deformation-energy orthogonality ahead of working face.Nowadays,squeezing deformation is adopted to evaluate stability ahead of working face simply,which is worth to further study.It is not suitable that tunnel axis should be parallel to horizontal maximum principal stress regulated by means of the relevant codes in different tectonic geostresses.Bolt has effect on formation of arch effect temporarily at initial stage of excavation.It can make the arch effect closer to tunnel and reduce effectively the peak value of tangential stress for surrounding rock at wall.With advance of working face,arch effect moves to deep rock.Therefore,staged arch effect is formed.

关 键 词：软岩隧道 高地应力 位移-能量正交 锚杆 稳定性 

分 类 号：TU452[建筑科学—岩土工程]