摘要
以往对于浅埋软岩隧道开挖影响的研究中较为缺乏考虑围岩开挖蠕变时效问题,文章针对西南地区某公路软岩中浅埋偏压隧道围岩变形特点,建立考虑岩体蠕变的有限元模型,通过引入强风化砂岩的蠕变系数,研究了相邻隧道开挖对既有隧道的影响,得到了既有公路隧道在相邻隧道开挖后无二次衬砌支护的情况下应力位移的变化结果,以及岩体塑性应变区范围的发展趋势和围岩主应力的分布随时间的变化规律。对实际工程中相邻两隧道间设计的隔离桩进行了模拟,证明了施加隔离桩后对既有隧道变形有效控制,围岩塑性区因隔离作用而减小,有利于工程开挖实施过程和工后的隧道正常使用,并通过工程监测得到证实。研究结果可为后续软岩浅埋偏压隧道的设计和安全施工提供有益的建议。
In the past,as for the research on the influence of shallow buried soft rock tunnel excavation consideration of creep time effect of surrounding rock excavation is relatively lacking.In this paper,according to the deformation characteristics of shallow embedded bias tunnels in soft rock of a highway in Southwest China,a finite element model considering rock creep is established.By introducing the creep coefficient of strongly weathered sandstone,the influence of adjacent tunnel excavation on existing tunnel is studied,and the results of stress and displacement change of the existing tunnel is obtained after excavation of adjacent tunnel without secondary lining support.Furthermore the development trend of plastic strain zone of rock mass and the variation law of principal stress distribution of surrounding rock with time are illustrated.In this paper,the isolation piles designed besides two adjacent tunnels in practical engineering are simulated.It is proved that the deformation of the existing tunnel can be effectively controlled after installation of the isolation pile,and the plastic zone of surrounding rock is reduced due to the isolation effect,which is beneficial to the excavation process of new tunnel and the normal operation of the tunnel.The research results can provide useful suggestions for the design and safe construction of shallow buried unsymmetrical tunnel in soft rock.
作者
黄懿
张文瀚
陈绪刚
蒋媛
李攀
HUANG Yi;ZHANG Wenhan;CHEN Xugang;JIANG Yuan;LI Pan(China Power Construction Group Chengdu Survey and Design Research Institute Co.,Ltd.,Chengdu 611130;Department of Geotechnical Architecture and Engineeering,Tongji University,Shanghai 200092)
出处
《现代隧道技术》
EI
CSCD
北大核心
2020年第S01期425-432,共8页
Modern Tunnelling Technology
关键词
隧道
开挖影响
蠕变
浅埋
偏压
Tunnel
Excavation influence
Creep
Shallow buried
Bias pressure
