Abstract:Research proposes:The construction of tunnel entrance is the key part of the whole engineering. According to the characteristics of the tunnel entrance, how to think in advance to design feasible scheme for the construction of entering the tunnel is the most important step. This scheme should not only decrease the engineering quantity of the tunnel entrance slope excavation and the support, but also protect the protophyte around the entrance. It can simultaneously accelerate the project progress and ensure the construction safety.
Research results:The tunnel entrance construction should be based on site topography,geology, hydrology, from the environmental point of view, to develop a scientific and rational program hole, using a reasonable construction technology, methods and steps to carry out the construction. The paper explains that the long-span tunnel construction method should be changed into the small-span method(such as CD method, CRD method, etc.)and auxiliary construction methods(such as ring type excavation with conservation of core soil, advanced entrance construction method, etc.),so as to effectively solve the potential safety problems and environmental problems.