The Preventive Disease Test And Surrounding Rock Instability Research Of Shallow Buried Large Span Multi-arch Tunnel

In the mountain area, the multi-arch tunnel is always applied to the high-grade road construction, due to its landform, geological conditions, road guidelines of even, vertical, and horizontal both in a respective and an interactive way, and industry city condition. Shallow buried large span multi-arch tunnel is used to avoid large engineering of roadcut construction, move of factory, mine and residents, pollute environment in the area with the complex condition of geography, cross road building. Because of the span of shallow buried large span multi-arch tunnel is large, mechanics characteristic is complex, and its shallow tunnel construction is also affected by the ground environment, some potential diseases may be occurred in the construction process. Therefore, it is necessary to develop the fast health examination and the rockmass stability appraisal work in the process of the tunnel construction, and guarantee a smooth, safe and economical effect in the operation of the tunnel.This paper introduces various diseases and nondestructive testing method in the process of construction, systematically summarizes the New Austrian Tunnelling Method(NATM) tunnel construction quality control technology standards, analyzes and compares the current major nondestructive testing technology in a rapid, economical and effective way through the use of transient Rayleigh wave, seismic mapping, and the acoustic method GPR method in disease detection of shallow long-span arch tunnel construction. In order to choose the rational way of excavation and support, evaluate the quality of rockmass in the huaishuping tunnel of Yu Deng freeway, we using the BQ classification method, the RMR classification method and the Q system classification method to mark the rockmass parameter and determine the rock classification. Rock mechanics parameters Hoek formula is forecasted on the basis of rockmass classification. By monitoring the tunnel measuration, the dynamic information of load-carrying capability and distortion in surrounding rock and shoring structure are got, and their load - carrying capability and distortion characteristics in the construction process are summed up.Through the preliminary study of this paper, it provides some reference to the design and deformation control in shallow buried large span multi-arch tunnel project, and achieve disaster prevention, mitigation and security operations.