公路连拱隧道是近二三十年来随着高等级公路建设发展而出现的一种隧道结构形式，具有较好的适用性和优越性，尤其适用于用地受限、山区地形复杂、道路展线困难等情况。然而，连拱隧道相对于分离隧道，施工中必然存在对围岩的多次扰动，施工难度较大。在浅埋、围岩软弱、岩溶等复杂地质条件下，这类隧道在不同施工阶段围岩的稳定性问题备受关注。以沪蓉西高速公路恩施至利川段白果坝隧道为背景，结合现场施工，利用三维弹塑性分析程序MIDAS-GTS对白果坝隧道进行了数值模拟研究，对围岩力学性状变化进行了分析，得到了隧道开挖施工中围岩的应力变化规律，针对薄弱部位提出了具体措施。

Highway multi-arch tunnel as a new structure form has been developed in resent decades with the rapid development of high level road, and this tunnel structure form has the merits of good adaptability and superiority in the condition of complex land form and difficult line designation. However, compared with individual tunnel and conjoined tunnel,multi-arch tunnel has the question of mother rock's frequent perturbation, construction difficulty, et al. In the geological condition of shallow buried, soft rock, and carst, et al. the mother rock of these kinds of tunnel must be paid attention in the whole construction stage. This paper, taking the Baiguoba Tunnel, Enshi to Lichuan section, Hurongxi express way, as the background and combining field engineering construction, analyzed the Baiguoba Tunnel with MIDAS-GTS, laid the emphasis on surrounding rock mechanics property, drew a conclusion of stress regularity, and put up the countermeasure to the weak part.