Abstract: Based on the specific condition of the Pengjia Garden Tunnel, the original construction plan is optimized during the construction. According to the numerical simulation of the construction condition, the two sets of construction plans which have been adopted during the construction process have been confirmed, reasonable excavation sequence and supporting methods are also recommended. On the basis of the active construction plan, we can obtain the influence on the arch and surface subsidence caused by the various working procedure. Combining the massive information obtained by the scene gauging, the studies of the settlement of the vault and the surface settlement have been carried out, so that we can exactly forecast the coming developments such as destroy、deformation and so on. Based on this, we can also come to some related conclusions, these achievements not only provide the extremely important instructional function to the project so that it can be carried out smoothly, but also pile up experience and practice material for the similar project in the future.

Key words: double-arch tunnel, numerical simulation, ground and crown settlement, construction method