以安徽省内某高速公路中双向4车道连拱隧道改扩建项目为依托，提出了10种连拱隧道改建方案，并从行车安全性、对既有工程的充分利用、交通组织易于识别等多角度对方案进行定性分析。根据定性分析结果选出3种较优方案，对3种较优方案从工程造价、施工难度、占压矿产等方面进行定量比选分析，并对隧道原位扩挖2种方案采用数值模拟方法建模分析，通过模拟结果得出： 1）大断面隧道改扩建中采取较强的支护可有效控制隧道变形； 2）方案1和方案2施工引起隧道位移和应力均可控，2种最大轴力值相差不大，但方案2位移控制效果更好； 3）大跨度隧道在改扩建或新建过程中，需注意隧道拱顶沉降和拱底隆起，其中拱底隆起问题更为突出。

For the reconstruction and expansion of multiarch tunnel of a 4lane highway in Anhui Province, ten kinds of reconstruction and expansion schemes are proposed. The ten schemes are qualitatively analyzed in terms of driving safety, how to take full advantage of existing tunnel and organize traffic easily, etc. According to the result, three better schemes are selected, and then quantitatively compared and analyzed from the aspects of engineering cost, construction difficulty and pressureoccupying mineral resources, and numerical simulation method is used to analyze the two schemes of tunnel insitu expansion. The simulation results show that: (1) Strong support in reconstruction and expansion of largesection tunnels can effectively control tunnel deformation. (2) The displacement and stress of the tunnel can be controlled in the construction with scheme 1 and scheme 2, and the maximum axial force values of the two schemes are similar, but the displacement control effect of scheme 2 is better. (3) For the reconstruction or expansion of largespan tunnels, attention should be paid to tunnel arch settlement and arch bottom bulging, and the problem of arch bottom bulging is more prominent.