Anti-seismic Research On Rational Structure Of Shed-tunnel

As the infrastructure engineering develops faster and faster, the development of traffic engineering has been growing with each passing day. Tunnel, as one of the key points of traffic engineering, has been deveoping rapidly. Our country locates between the Eurasian Earthquake Zone and Circum-Pacific Earthquake Zone, subjects to earthquake at frequent intervals and becomes to be the largest strong earthquake area of shallow earthquake in mainland. What's more, the seismic disaster in the area has characteristic feature of wide distribution, high intensity and strong damage. These opencut, containing shed-tunnel and opencut in the shape of arch, were often destroyed in the earthquake disaster, and makes more difficulties for the disaster relief officials. Besides, the earthquake often makes landslide in the slope and upward slope of the tunnel, accumulates collapsed rock in the access of the tunnel and blocks the traffic. Therefore, the most important thing of disaster relief against earthquake we should do is to reinforce the aseismic capability of the opencuts, such as shed-tunnel.As shed-tunnel often has low depth and thin surface cover, it's easier to be damaged in earthquake. Thus, it's very essential to study the aseismic stability of shed-tunnel and rationality of aseismic shed-tunnel structure form.This paper provided a study of construction process and rational aseismatic structure of a shed-tunnel. The main content of this study contains following aspects:â‘ Five types of shed-tunnel structure were analysed, and the development prospect, the advantages and disadvantages of shed-tunnel were discussed,â‘¡According to the construction principles and the construction steps, the whole construction precess of a shed-tunnel was simulated with Finite Element Method and its relavant software.â‘¢According to the characteristic feature of shed-tunnel and ground structure, the sesmic response of several types of shed-tunnel was analysed with the unified viscous-spring boundary for static and dynamic analysis. On the base, a rational aseismic structure form was proposed.â‘£The 3-D finite element modal of the connection part of a tunnel and its shed-tunnel was built. The relationship between the seismic response and the joint type in the shed-tunnel and the hidden hole under seismic load was studied.Through the simulation of the construction precess of the shed-tunnel, the study showed that: in the construction process of shed-tunnel, the effect of slope and thickness to shed-tunnel structure should be paid attention to; the main stress in the key part of shed-tunnel with semi-arch and inclined column were smaller than that of shed-tunnel with semi-arch and straight column. It indicated that the structure of shed-tunnel with semi-arch and inclined column were more rational than that of shed-tunnel with semi-arch and straight column.Through the serismic analysis of a shed-tunnel, the result showed that: compared with other kinds of shed-tunnel structure, shed-tunnel with semi-arch and inclined column had better stability and aseismatic capability; if strenthened with bearer, the aseismatic capability of shed-tunnel was better than that without bearer. It also indicated that in the seismic area, the stiffness of the joint part should be reinforced at the joint face of the shed-tunnel and the hidden hole to reduce the damage of the earthquake to the shed-tunnel structure.A more rational structure form was proposed in this paper. A recommendation for the joint form between shed-tunnel and hidden hole was provided. The achievement could give a preference for the design and construction of shed-tunnel.