隧道洞口浅埋偏压段超前支护方案数值模拟  

Numerical Simulation of the Advance Support Scheme of the Shallow Buried Bias Section of the Tunnel Opening

作　　者：陈家征 李忠[1,2] 韩炀[1,2] CHEN Jiazheng;LI Zhong;HAN Yang(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;The Ministry of Education Jointly Established the Key Laboratory of Road and Railway Engineering Safety and Security,Shijiazhuang 050043,China)

机构地区：[1]石家庄铁道大学土木学院,河北石家庄050043 [2]道路与铁道工程安全保障省部共建教育部重点实验室,河北石家庄050043

出　　处：《粉煤灰综合利用》2024年第4期59-66,共8页Fly Ash Comprehensive Utilization

摘　　要：由于山岭隧道洞口段多处于浅埋偏压地形,为保证施工进洞安全,常常需要采取超前支护以控制洞口段围岩变形,保证围岩稳定。以彝良隧道洞口段为工程背景,采用FLAC 3D有限差分软件,分别建立无超前支护、管棚超前支护、超前小导管超前支护和管棚+超前小导管联合超前支护方案进行比选分析。计算结果表明:超前支护可大幅度降低围岩竖向位移、水平位移、竖向应力以及抑制拱顶塑性区发育;从支护效果上看,管棚支护效果最佳,管棚+超前小导管联合支护次之,超前小导管最差;从管棚长度自身以及施工经济合理性考虑,在控制围岩变形效果相当的条件下,采用管棚+超前小导管联合支护较佳。研究可为类似浅埋偏压隧道洞口段超前支护方式的选择提供借鉴。Due to the portal section of mountain tunnel is mostly located in the shallow buried and unsymmetrical pressure terrain,in order to ensure the safety of tunnel entry,advance support is often required to control the deformation of surrounding rock at the portal section and ensure the stability of surrounding rock.Taking the portal section of Yiliang Tunnel as the engineering background,the FLAC 3D finite difference sofware is used to establish no advance support,only pipe shed advance support,only advance small pipe advance support and pipe shed+advance small pipe combined advance support schemes for comparison and analysis.The calculation results show that the advance support can greatly reduce the vertical displacement,horizontal displacement,vertical stress of surrounding rock and inhibit the development of the plastic zone of arch crown.From the perspective of the support effect,the pipe shed support is the best,followed by the pipe shed+advance small conduit combined support,and the advance small conduit is the worst.Considering the length of pipe shed and the economic rationality of construction,under the condition that the effect of controlling the deformation of surrounding rock is equivalent,it is better to use pipe shed+advance small conduit combined support.The study can provide theoretical guidance for the selection of advance support methods for similar shallow buried tunnel portal section under eccentric pressure.

关 键 词：浅埋偏压隧道 超前支护 管棚 超前小导管 数值模拟 

分 类 号：U455.7[建筑科学—桥梁与隧道工程]