Abstract:

At present, there is a lack of relevant construction standard for largediameter vertical shafts of highway; and the composite lining and singlerow operation would induce complex working procedure, slow construction speed, deficient corresponding construction machinery and low safety. Hence, based on the main supporting and excavation technology of deep shaft in coal mine, ventilation shaft layout of operation highway tunnel, and existing supporting and excavation technology of highway, the vertical ventilation shaft schemes of Micangshan Tunnel are studied. The single shaft layout scheme of singlelayer formwork concrete lining and short section excavation and lining is selected, which has been successfully applied to a deep vertical shaft with diameter of 9 m and depth of 431.8 m. The engineering practice shows that: (1) Under the same ventilation area, the engineering quantity of double shaft is less than that of single shaft, but the cost is higher than single shaft due to its high equipment cost. (2) The construction schedule and safety of singlelayer formwork concrete lining and short section excavation and lining are superior to those of singlerow operation of composite lining and excavation. The results can provide technical support and experience for the construction of deep and large vertical shafts in the future.

Key words: highway tunnel, vertical shaft, scheme comparison, singlerow operation, singlelayer shaft wall, operation by short section excavation and lining