Study On Goaf Area Construction Technology Of Huayingshan Tunnel Of Nandaliang Expressway

At present, there is much theoretical research and engineering practice about the construction, protection and consolidation of the lower goaf area of the highway in china, while the research on those of the highway and railway tunnels is relatively less.Therefore, taken Huayingshan Tunnel of Nandaliang Highway as engineering background and based upon the systematical analysis and conclusion of Huayingshan Tunnel and the construction experience of goaf area in crushed surrounding rock at home and abroad, this paper gets the safety influence of goaf areas upon tunnels through numerical simulation and then proposes the construction technique of safe passing the goaf area. The main research in this paper is as follows:1. the research on geological conditions of tunnel scope engineering;Combined with the materials of the engineering geological investigation, physical and mechanical parameters are determined, and the distribution range, the classification of surrounding rock and the stability of deformation are ascertained.2. the research on the interaction between goaf areas and tunnel structures, and the construction methods.By building the theory analysis model, adopting the numerical analysis method to simulate the process of tunnel construction, and analyzing the mechanical behavior of surrounding rock and supporting structure and the influences of goaf area upon the tunnel structure and the stability of surrounding rock, the safe distance that affects tunnel construction can be put forward, and the impact of goaf area on tunnels also can be estimated qualitatively. Consequently, reasonable construction plans and reinforcement measures of tunnel construction can be found. Then, the reasonability of construction plans, the necessity of the supporting devices should be assessed. To ensure tunnel construction and operation safety, construction methods and assistant measures should be adjusted timely.3. the research on pouring treatment of goaf areaFirstly, the numerical simulation model is built. Then the grouting consolidation treatment, which is done in the influential area of the steeply inclined goaf area in the entrance region of Huayingshan Tunnel in the tunnel lower part is simulated. At the same time, the evaluation about effects of the simulation should be made, and then results of the grouting consolidation can be analyzed from the qualitative perspective.4. the research on construction technique of the goaf area of Huayingshan TunnelBased on the previous engineering experience and numerical simulation. the specific construction techniques of goaf area of Huayingshan Tunnel are proposed, which can provide directions for future construction.