Research On The Structural Properties Of Asphalt Yangtze River Tunnel Pavement With Great Longitudinal Slope And Rigid Base In Wuhan

As the rapid development of the world's economic, Chinese infrastructure construction scale is faster sprawl. Our domestic highway tunnels, particularly the river-crossing tunnels have being builded in larger numbers and greater length. At present, the Yangtze River Tunnel in Shanghai, Nanjing, Wuhan, Chongqing, and subsea tunnel in Xiamen, Qingdao and Dalian, all of those great cross-river/sea tunnel have being built. With the difficult technology and high investment costs, the construction level and the operation quality of those projects will make a profound impact on our country transport infrastructure development. Among that technology, the large longitudinal structural properties of asphalt pavement in tunnel is one of the key technologies.Therefor, domestic and foreign experts have done little on the large longitudinal study of tunnel Asphalt Pavement, the majority is also limited on structural design, material composition research of the small slope of asphalt pavement. But lots of builded projects shows that the existing research results of the small slope of asphalt pavement are not appropriate to the large longitudinal subsea tunnel, especially in large traffic flow and the re-overload range. In order to ensure a rationality pavement structure and scientific combination materials designed in future construction of large scale river-crossing-tunnel road, the article takeing Wuhan Yangtze River Tunnel project as object, according to the traffic environmental features, doing a systematic study on structual mechanical properties of asphalt pavement with great longitudinal slope and rigid base in river-crossing-tunnel, which can achieving the structural and functional match in expressway tunnel road.The study is supported by 863 of Wuhan Yangtze River Tun nel programe. According to the characteristics of heavy traffic , steep slope slippery pavement,and reinforced base of the tunnel road, it taking a systematic study on the road surface shear stress, bending stress and deformation of the tunnel structure, in the affects of the temperature changes, slope gradient size, loading rate, the stiffness value of mutation and inter-layer contact conditions. By which we can ensure the optimal control parameters of structure and material properties, give a typical structure of great longitudinal slope and rigid base asphalt pavement. All the results of this paper are parts of the 863 project of "Anti-slide, fire-retardant, noise reduction multi-purpose structure of the tunnel road pavement design and technology".In this paper, all the researches and results are as following: 1. Analysing the climate, environment, traffic conditions, pavement structure, material composition and performance information by the domestic and international surveys, the paper focuse on the problems/characteristics of road materials and the structural, put forward the requirement about structure and performance.2.With the background of Wuhan Yangtze River Tunnel Project ,according to the environmental climate and traffic flow, it build a three-dimensional surface structure of non-linear finite element model in the conditions of longitudinal, rigid base tunnel, research the road surface shear stress, bending stress and deformation of the tunnel structure, in the affects of the temperature changes, slope gradient size, loading rate, the stiffness value of mutation and inter-layer contact conditions. Optimize the hierachical compositional of the tunnel pavement, and give the structure of a typical tunnel pavement and its related performance indicators and the optimum range of material parameters values.3.This conclusion of the asphalt pavement of a typical tunnel pavement structure is not only to ensure the anti-slide tunnels, fire-retardant, noise reduction level of function, but also to increase stiffness of pavement structure, improve the road ability of anti-rutting;4. The research shows that the structure and material of the Large-scale longitudinal cross the great river or sea tunnel asphalt pavement must following the conditions below:1) the Reasonable thickness of the tunnel asphalt pavement should between 7 to 15cm, and the thickness of the Asphalt top layer h1≥4cm, the material elastic modulus of asphalt below layer E1≥800MPa;2) if the slope gradient equip to or large than 6% ,the shear strength of asphalt top layer of large longitudinal tunnel compound asphalt pavement should larger than 1.0Mpa, the material elastic modulus of asphalt below layer E2≥2000MPa;3) Thin layer of asphalt of the Yangtze River Tunnel longitudinal rigid base asphalt pavement layer composite structure should be connect by the way of uniform spread high-viscosity asphalt oil, in this way to enhance the structural integrity and uniformity of transmission.