Study On Deformation Characters And Controls Of One Room Excavation Of Hydraulic Plant

In recent years, with the rapid development of Chinese economy, constructions of underground engineering change with each passing day and more and more shafts have been applied to underground engineerings. In process of shaft's excavation, the problem of transformation and stability is unavoidable. The excavation of shaft in underground pump station as the object of study in this text, several aspects of work have been done as below.Above all, it summarizes the development of the current state of underground projects home and abroad, especially some focus problems of deformation during the excavation of the underground project. In the process of underground project's excavation, the deformation calculation and deformation control is one of the key points. However, underground structure and rock and soil masses are comprised of kinds of medium in highly complex space system. The transformation and safety are synthetically influenced by multiple factors. It's been common view that how to ensure projects stability themselves and control the displacement of underground structure and rock and soil masses effectively at the same time. The design of safety, economy and rationalization must be attained through using the finite-difference software of Flac3D to simulate the excavation process of the shaft and the wall rock displacement field and stress field have been simulated to draw deformation curves of displacement.Following, it systematically explains the mechanical theory, behavior and characteristics in the process of excavating the shaft and underground engineering, and then, its theory foundation is combined with both classics underground structure excavation theory and FDM (finite difference method).And then, based on excavation of shaft in underground pump station in Shenzhen, the characters of displacement of wall rock and settle of earth surface will be get through analyzing the excavation process of shaft. Some elementary conclusions have been derived as below:â‘ The deformation curves of horizontal displacement of short side and long side directions is different, maximum value of shor side displacement presents to the top of the wall but maximum value of long side displacement presents to the middle of the wall which is small at begin and end, but big in the middle, which likes a fish stomach shape.â‘¡It is the 18m depth that the displacement of its end on the whole. The upper construction almost has no effect to the displacement.â‘¢The deformation curves of settle of earth surface appear triangle and groove, which is the same as settle of earth surface of deep foundation pit.At last, on basis of simulation of shaft excavation in underground pump station in Shenzhen, further study on effect factors of excavation deformation of shaft has been done and some further conclusions have been derived:â‘ The initial stress has an significant influence on excavation deformation of shaft that the greater the initial horizontal stress, the greater its excavation deformation.â‘¡The elastic modulus of wall rock has an significant influence on excavation deformation of shaft that the greater the elastic modulus, the smaller its excavation deformation.â‘¢Time effect has an obvious influence on excavation deformation.â‘£Space effect is another important effect factor on excavation deformation. On these basis, put forward theory of deformation control.