Abstract: In order to obtain the specific characteristics of subsidence，crown settlement，and support stress of shallow buried and asymmetrical neighborhood tunnels under surface loads in the process of construction，two processes of construction based on the Chongqing Yuzhong tunnel project were analyzed using a 2D numerical simulation method when the surface load was distributed over the small tunnel，the large tunnel，or two tunnels.The research results show that when the small tunnel is constructed with the unilateral pilot tunnel method and the large tunnel is constructed with the ring cut method，the larger the total surface load is，the larger the subsidence of ground is.The surface load affects the value of final subsidence and shape of the curve of subsidence.The construction procedure of the tunnel has no effect on the law of crown settlement.The excavation of the following tunnel close to the antecedence tunnel has great influence on the supporting stress of antecedence tunnel.The results can provide theoretical support and scientific guidance to similar construction projects.

Key words: tunnel engineering, shallow buried, asymmetric neighborhood tunnel, surface load, subsidence, support stress

摘要： 为获得浅埋非对称小净距隧道在地表荷载作用下的地表沉降、拱顶下沉和支护应力在施工过程中的变化特征，依托重庆渝中连接隧道工程 为依托，采用二维数值分析方法，分析了地表荷载位于小隧道正上方、大隧道正上方及均布于大小隧道上方3种荷载作用下，先行洞为小隧道或大 隧道两个施工过程。结果表明：当小隧道采用单侧壁导坑法和大隧道采用环形开挖留核心土法施工时，地表总荷载越大，地表沉降越大，地表荷 载影响最终地表沉降曲线的形态及沉降值大小；大小隧道的施工先后顺序对拱顶下沉随工序变化的规律没有影响；后行洞临近先行洞的开挖对先 行洞的支护应力影响非常大。分析结果可为类似工程建设提供理论支持和科学指导。

关键词: 隧道工程, 浅埋, 非对称小净距隧道, 地表荷载, 地表沉降, 支护应力