Study On Numerical Simulation On Construction Processing For A Silo Of The DaPingLi Tunnel

In recent years, with the rapid development of China's economy and the construction of the highway changes quickly, more and more highway tunnels are constructed. The stability problem of the ventilating silo and transport business process for the longitudinal ventilated tunnel will arise during the construction. The essay takes the ventilating silos of highway tunnel as the research object, main works are the following:Above all, it summarizes the development of the current state of underground project home and abroad, especially some focus problems of optimization during the excavation of the underground project. What is to say is how to forecast the displacement evolvement rule of the large-scale underground and safety of project according to both feedback information and historical data (wall rock displacement) measured from construction site. Moreover,original design plan is revised or changed according to the result, which actualizes science of decision-making and information of construction. In additional, the design of safety, economy and rationalization must be attained thought using the computational technology to simulate the excavation process of the tunnel and the wall rock displacement field and stress field after the tunnel excavation, then the plastic area are done.Following, it systematically explains the mechanical theory, behavior and characteristics in the process of excavating the tunnel and underground engineering, and then, its theory foundation is combined with both classics underground structure excavation theory and FEM (finite element method).At last, based on the 3# silo of DAPINGLI tunnel, dynamic response of wall rock displacement and stress are analyzed during the construction process of silo. Some conclusions are derived: the displacement of silo wall in the x direction is small at begin and end, but big in the middle, which likes a fish stomach shape; it is the third steps that the displacement of its end on the whole. The upper construction almost has no effect to the displacement; the stress of wall rock changes with excavation and supporting; the plastic area of wall rock concentrates mainly on the part between the liaison air flue and silo. The conclusions drawn in the different stress release ratio are as follows: the displacement of all rock increased obviously with the enlargement of stress release ratio; there is a little effect on the stress of wall rock with the change of stress release ratio; the plastic strain of surround rock augments with the increase of stress release ratio.