论文首先从影响隧道围岩稳定性的工程地质因素入手，对西庄隧道围岩的变形破坏机制进行了分析和探讨。针对该隧道结构面和薄夹层发育且围岩具有弹塑性性质的地质特征，提出隧道的变形破坏主要受强度-应力控制，破坏方式表现为顶拱部位的张裂塌落和劈裂剥落破坏； 其次，结合工程实际，考虑到西庄连拱隧道特定的工程地质条件，根据《公路隧道设计规范》（JTGD70—2004），并对初始地应力、地下水和软弱结构面等影响因素进行修正，确定了洞室围岩岩体质量指标[BQ]值，作为围岩分级的参考指标。确定出西庄连拱隧道的围岩级别为Ⅳ、Ⅴ级； 然后，通过建立弹塑性模型，应用有限元ANSYS程序对该隧道施工过程中的变形情况进行了仿真模拟，对三导洞方案修建双连拱隧道时围岩和结构的受力、变形规律进行了详细分析； 最后，建立空间线弹性模型，对双连拱隧道开挖时的空间效应和左右洞的相互影响，以及中隔墙的变形和稳定性进行了模拟分析，为软岩双连拱隧道的设计与施工提供了依据和指导。

The double multi-arch tunnel which is a new large span tunnel is presented with the rapid development of high way building in our country. Its route is fluent and impropriating the area is small and the ratio of utilizing space is high. It is easy to connect the out road with avoiding the embankment in the tunnel exit or the bridge framing. It has the advantages of adapting the condition and protecting the environment and engineering quantitatively. The removing building is reduced and the engineering charge is reduced by using the double multi-arch tunnel during the construction in city. The double multi-arch tunnel is designed under the condition buried shallow tunnel with the moderate to short length. The surrounding rocks will happen when the load is removed and returned and the stress will be redistributed during tunnel digging. The surrounding rock will lose the stability when its strength is too low to adapt the stress redistribution. It will bring out the deformation and failure of surrounding rock if we do not reinforce timely or cannot assure the quality of reinforcement, which will take some disadvantages for the construction and operation of the underground building. Because the geological condition is poor during the construction of double multi-arch tunnel, the hidden trouble of the surrounding rock instability and desformation exists. So it is a important content with closely relating to the construction of tunnel and operation in the high way that analyzing the stability of surrounding rock. Base on the construction double multi-arch tunnel of the Nanshi-Mengyang high way, the tunnel construction is simulated by analyzing the stability of the surrounding rock and protecting the stability of the surrounding rock and supervising the construction. The most weakness site of the surrounding rock stress strength is pointed out during the process of the tunnel construction. The local instability and breakage of surrounding rock is forecasted and prevented which can assure that the stability of surrounding rock can arrive at the requests. The stability of surrounding rock is analyzed systemically by the methods of combining the body analysis with the local analysis. At first, base on the geological engineering factors of influencing the stability of surrounding rock, the mechanism of deformation and failure for the surrounding rock is analyzed and discussed. Aim at the geological characteristics of the elastic-plastic properties of the structure face and the shallow interlayer, the strength-stress controlling mechanism is thought as the main mechanism of deformation and failure. The destroy manner of spreading collapse and fracture flaking is the main manner for the surrounding rock.. Secondly base on the engineering geological condition of the double multi-arch tunnel in the Xi Zhuang, the factors of the initial geo-stress and the underground water and the weak structure surface is modified properly by utilizing the national code “Classification Standard for Engineering rock”. The classification of surrounding rock of double multi-arch tunnel in Xi Zhuang is analyzed exploringly. The quality index (BQ) of surrounding rock is confirmed which can use to reference for the classification of surrounding rock. The classification of the surrounding rock is the Ⅳ type by analyzed all kinds of classifications of surrounding rock. The tunnel construction is simulated by the program of ANSYS after building the elastic-plastic model. The stress states during the construction is simulated. The rules of the stress and distortion in the surrounding rock and structure is analyzed detailedly for the double multi-arch tunnel building in the three hole. The elastic space model is built at last. The space effect during the dig of double multi-arch tunnel and the interactional of the right hole and left hole is simulated, at the same time the distortion of dividing-wall is simulated too. It can give some advances for the design and the construction of double multi-arch tunnel in the soft rock.