Temple Will Ping Arch Tunnel Halfway Half Tunnel And Structural Mechanics Of The Half-dark Features

With the development of the expressway, double-arch tunnel has been applied widely. Because of complex alpine terrain, it is inevitable that tunnel portal structure and topographic contour lines were oblique crossing, half tunnel and half road is a effective method to solve this problem. In the half tunnel and half road scheme, the left and right excavation surface of the tunnel entrance are set up respectively in their suitable position in this program, and use opencut tunnel to connect to the whole double-arch tunnel in order to reduce the slope of the excavation hole height, the tunnel excavation, and the supporting structure, while it can also ensure the safety of holing through in tunnel construction, reduce the area of tunnel entrance and reduce the destruction of the natural landscape of tunnel entrance.Based on the field monitoring data gathered in Dianhuiping tunnel of Changsha-jishou temple part, by using ABAQUS program to do numerical model, the paper has made the contrast and analysis of two construction methods, the detailed conclusions works are as below:(1) In construction, the structure composed by side wall and horizontal pipe roof similar to trellis undertake most of the load, it is significant to guarantee the safety and stability of the structure, the majority of load transfer from the horizontal pipe roof to the side wall throughout the construction process.(2) Side wall The foundation of side wall is the key of the stability of the entire tunnel, in tunnel construction and operation of the process, bias load will delivery to side wall foundation through a variety of support structure. Side wall not only to resist lateral displacement of the tunnel structure, but also to resist the overturning trend caused by the side wall's bias load, therefore the design and construction of side wall foundation is the key to ensure the safety of the tunnel structure construction and operation, particularly, the side wall anchoring steel beam must have sufficient pull-out force.(3) Half-dark program is more effective than half tunnel and half road program to control the structure deformation. Compared with the half-dark program, the middle wall stresses in the half-dark conditions is less 50 percent, but the maximum stress of lining in the half-dark conditions are nearly 10 times as that in halfway and tunnel condition. It is very unfavorable to the structure design and construction and security operations. At the same time, the construction procedure in half-dark conditions are so multiple and complex. Therefore, the Tunnel of Ding Huiping adopted the halfway program is reasonable.