摘要
为了研究卵石层构造参数对隧道围岩稳定性及地表沉降的影响规律,建立不同围岩(卵石层)参数条件下的离散元数值计算模型,并进行了不同试验工况的对比分析。结果表明:在卵石层不同构造参数条件下,隧道开挖引起的地表沉降曲线能与Peck公式较好拟合;当“节理倾角”在30°~35°之间时,隧道顶部地表沉降峰值最大,沉降槽宽度系数最小;同时,“节理倾角”增加使得剪切变形区域由拱顶逐渐向两侧延伸,并形成贯通破裂面;破裂面与最大主应力作用方向的夹角接近45°,并将拱顶和拱腰附近的围岩切割成锥形松动体;此外,隧道开挖初期围岩(卵石层)受拉破坏区主要集中于拱圈附近,而破坏区范围随着卵石块体间摩擦角的增加逐渐减小;工程实际中可通过注浆措施提高拱圈围岩稳定性,对此类工程设计、施工具有理论指导意义。
To investigate the impact of pebble layer structural parameters on the stability and surface settlement of tunnel surrounding rock,a discrete element numerical calculation model is established under different parameters of surrounding rock(pebble layer).A comparative analysis of different test conditions is conducted.The results indicate that the surface settlement curve caused by tunnel excavation can fit well with the Peck formula under various structural parameters of the pebble layer.Specifically,when the“joint indination angle”ranges between 30°and 35°,the peak value of surface settlement at the top of the tunnel is maximized,the width coefficient of sedimentation trough is minimized.Furthermore,the increase in“joint inclination angle”leads to gradual extension of shear deformation area from vault to both sides,eventually forming a fracture surface.The angle between fracture surface and direction of maximum principal stress is approximately 45°,resulting in formation of conical loose body around vault and arch due to cutting action on surrounding rock.Additionally,the tensile failure area within surrounding rock(pebble layer)primarily concentrates near arch ring during initial stage of tunnel excavation.However,this failure area gradually diminishes as friction angle between pebble blocks increases.In practical engineering applications,grouting measures can enhance stability around arch ring,finding with significant theoretical implications for design and construction in similar projects.
作者
杨治军
胡金鑫
邱成虎
王文卓
曾洋
YANG Zhijun;HU Jinxin;QIU Chenghu;WANG Wenzhuo;ZENG Yang(Gansu Province Transportation Planning,Survey&Design Institute Co Ltd,Lanzhou 730030,China;School of Highway,Chang’an University,Xi’an 710064,China)
出处
《土木工程与管理学报》
2024年第4期76-82,共7页
Journal of Civil Engineering and Management
基金
甘肃省交通运输厅科技项目(2021-09)。
关键词
卵石地层
离散元
围岩变形
地表沉降
pebble layer
discrete element
surrounding rock deformation
ground subsidence
作者简介
杨治军(1993-),男,甘肃白银人,硕士,工程师,研究方向为隧道工程(Email:yzj43256@163.com)。
