Abstract：Neighborhood tunnel is often located at the entrance. When the section is super-large, it always has the characteristics of poor geological condition, many procedures and strong interference. If excavation segments are too many which affect the work efficiency, otherwise, the tunnel is easy to lose stability, so the reasonable excavation method is important to choose. Relying on Daling tunnel of Ji′nan expressway connecting line, methods of numerical analysis and field monitoring have been used to study on the applicability of half-step CD method, CD method and double side-heading method. Seveal indexs have been choosen to analyze the mechanical behaviour, such as vault settlement, horizontal displacement and stress of shared rock. The second tunnel construction has an impact on the first one, for the different construction method, influence sort from large to small is half-step CD>CD>double side-heading method. The impact of half-step CD method isn′t significantly higher than CD and double side-heading method and the maximum amount is 12%. Therefore, half-step CD method can be adopted. Monitoring data of stress and displacement of steel frame show that half-step CD method can ensure the project safety, short the construction period and reduce costs, which is the most suitable method. By using half-step CD method, Daling tunnel produce good economic and social benefits, which can guide the tunnel′s design and construction under similar geological conditions.
