Seismic Response Process Analysis of Concrete Lining in Hydraulic Tunnel

Dynamic response of concrete lining structure in hydraulic tunnel under seismic load is of great importance for engineering design and safety assessment, and it is the key link to establish a scientific and reasonable dynamic constitutive model and a coupling analysis method of inner water and lining for the seismic research of lining structure. In light of the basic idea of static damage constitutive in strain space, the static tension and compression damage variables for concrete under three-dimensional stress state were defined and solved. According to the similarity principle of constitutive relation curves of concrete under static and dynamic loading, a dynamic damage constitutive model of concrete suitable for programming was developed. Based on the explicit finite element method for analyzing the dynamic response of single-phase solid and fluid medium, combining with the boundary condition at coupling interface, a dynamic explicit finite element analysis model considering the coupling interaction of lining and inner water was presented. This method could directly integrate, solve without simultaneous equations, and greatly simplify the calculation process. Moreover, it could be easily used to analyze wave propagation problems with a variety of mediums. Taking some diversion tunnel as an engineering example, the calculation results show: 1)various parts of concrete lining are in a synchronous vibration state, but the displacement of haunch is obviously less than the vault and inverted arch; 2)the maximum principal stress quickly increases, and exceeds the tensile strength, in which the haunch is remarkably influenced, leading to great stress increment and serious damage; 3)the cracking zones gradually extend from the haunch to each side, and the inner lining directly interacting with fluid is the weak link of seismic design. This model could reasonably reflect the seismic response characteristics of concrete lining in hydraulic tunnel, and an effective analysis method was provided for the aseismic design of hydraulic tunnel. © 2017, Editorial Department of Advanced Engineering Sciences. All right reserved.