Abstract
The seismic response of hydraulic tunnels is a complex nonlinear process. What makes the case even more interesting is that the large amount of water in hydraulic tunnels which is likely to induce considerable hydrodynamic pressure acted on tunnel structures during earthquakes. In this work, a full three-dimensional (3D) dynamic finite element model is adopted to conduct a comprehensive assessment of the seismic behaviors of a hydraulic tunnel system. In this analysis, the plastic-damage model is employed to reflect the nonlinear mechanical behaviors of the concrete lining, and a fluid-solid coupling method based on an explicit weighted residual approach is proposed to consider the effects of the hydrodynamic pressures on the seismic response of the hydraulic tunnel. The numerical results indicate that the hydrodynamic pressure contributes to a greater seismic response of the tunnel structure. When the hydrodynamic pressure is considered, the magnitudes of the maximum principal stresses are likely to increase by 50% and the displacement amplitudes are approximately 2 cm more than that of without hydrodynamic pressure. The hydrodynamic pressure exacerbates the damage degree of the tunnel structure, and the waist suffers the most severe damage.
Highlights
Due to the population growth and urbanization of China in the past dozen years, water resources in some regions are insufficient to meet daily domestic and industrial water use; many hydraulic tunnels have been built to solve the water shortage problem
Since the main purpose of this paper is to study the response of the hydraulic tunnel under the horizontal lateral excitation (x-axis direction in Figure 1), it can be generally assumed that the fluid in the tunnel is a steady uniform flow and there is no tangential interaction between the fluid and the structure
The work in this paper aims at the nonlinear seismic response characteristics of the tunnel and the effects of the hydrodynamic pressure on the response process
Summary
Due to the population growth and urbanization of China in the past dozen years, water resources in some regions are insufficient to meet daily domestic and industrial water use; many hydraulic tunnels have been built to solve the water shortage problem. Tunnels in seismically active areas cannot avoid the earthquake-induced risks. Great efforts have been made by many researchers to investigate the seismic behaviors of tunnels using various methods (e.g., the field investigation, scaled model tests, theoretical analysis, and numerical simulation). Naggar et al [10] built a closed form solution for inplant moments and thrusts in tunnel linings and studied the impacts of the incident angles on the seismic responses. Yashiro et al [4] proposed a simple classification method for the seismic damage forms of tunnels and summarized their damage mechanism. A 3D input method of shear waves was employed by Huang et al [11] to investigate the impacts of the incident angles on the seismic response of a long lined tunnel. More relevant works on the seismic behaviors of tunnels can be found in [12,13,14,15]
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