Research On The Fast Contruction Technology Of Putaoshan Super Long Highway Tunnel (in Youyang)

Putaoshan tunnel is a long highway tunnel with two tubes for four driveways. The construction is divided into 2 bids of G4 and G5, and the excavation is developed by two bureaus from the two ends of the tunnel. The engineering geological condition and the difficulties in construction are firstly studied in this thesis. And the conclusions are drawn out that the engineering geological condition is very complex and difficult for the construction, and that the space at the tunnel opening is too confined to carry out the construction, and that it is difficult to excavate the tunnel opening because of the wall rocks' lower stability, and that there are not any assistant sap for aeration or smoke evacuation, and that the engineering work amount per month is very large because of the limited time and the large work amount of the whole tunnel.Basing above, the following four concepts are researched in this thesis for the fast construction without accidents.Firstly, construction techniques of similar tunnel opening are studied. The main idea of the techniques is to change the traditional construction of the opening sequence and construction technology. According to the techniques, before the construction of the hidden hole, a temporary lining will be formed as a conservatory measure of the micro-excavation front slope. The hole slopes the native vegetation can be preserved from damaged. The front slope will be steady and the protection engineering of the front slope can be reduced. So the construction techniques is worth generalizing.Secondly, hydrodynamic dynamiting technique is also studied and analyzed minutely in this thesis. The combined application of hydraulic pressure blasting and smooth blasting is adopted in Putaoshan tunnel. As the results, the tremble induced by the dynamiting is smoothed, and the economical benefit is increased. The over-break and under-break are reduced by leaps and bounds. The wall rock is crashed equably without large numbers of big mass. The combined application technique is useful for mechanized construction and taking out the slag quickly. It is also in favor of gas defence and smoke removal. The process of smoke removal can be shorten, and the construction circumstances can be improved, so the health of the construction people can be guaranteed. Extra excavation length of 20cm can be achieved in each cycle, and then the construction can be completed ahead of schedule.Thirdly, the construction techniques under ill-geological conditions are studied. According to the changing of the site construction conditions and the results of the survey, the construction measures are changed to complete the engineering in the time limit with the help of advanced anchor bolt, granting, and U-like steel arching and other methods.At last, fast construction organizing techniques are analyzed minutely. The pressing and feasible construction measures and optimized construction methods are put forward in this thesis. The general arrangement and main establishments before construction are programmed carefully. The studying on aeration during the construction and the relative engines and techniques are strengthened. The construction management is amply analyzed and demonstrated. Fast hole forming in this tunnel is carried out successfully.The research results of this thesis can be good references for tunnel constructions in similar geological area, and they will have helps to safe, fast, and good quality tunnel construction.