Abstract
The safety and stability of lining structures are core concerns of tunnel and underground engineering. It is crucial to determine whether a lining structure would crack and which direction the crack would expand with seismic excitation. In previous literature, the principle based on stress and strain has been widely used to predict the seismic damage of lining structures, whereas it cannot specify the cracking modes. Taking account of that deficiency, this paper introduces the strain energy density ratio (SEDR) principle and proposes a seismic damage prediction method for lining structures, which can precisely predict the crack positions and expansion directions. Moreover, numerical simulations of the typical seismic damage sections of two tunnels in the Great Wenchuan Earthquake and a calculating example of the theoretical equations are conducted to verify the proposed method. In summary, the numerical simulation results show that the arch springing cracks first, and the invert cracks next; then the cracks expand to the spandrel, and finally, they form oblique cracks, annular cracks, and longitudinal cracks, whose positions and patterns are in accordance with the field investigation results. In terms of the calculating example results, the obtained two-fold SEDR and cracking angle θ are 1.87 and −6.28°, respectively, which are consistent with the numerical simulation results. Therefore, one can see that the proposed seismic damage prediction method based on the SEDR principle is quite accurate. This method can be used to predict the seismic damage of lining structures and provide a reference for the research of the damage mechanism of tunnels.
Highlights
As an important part of lifeline engineering, tunnel and underground engineering faces challenges in avoiding highintensity seismic zones due to line requirements. erefore, a tunnel may be severely damaged and difficult to repair if the tunnel is struck by a strong earthquake, even leading to extreme property losses and casualties
Aiming to analyse the seismic response of tunnel structures, this paper introduces the initial damage variable of concrete materials and conducts numerical simulations based on the strain energy density ratio (SEDR) principle to simulate the typical seismically damaged sections of two highway tunnels in the Great Wenchuan Earthquake
This paper compares the numerical simulation results with the field investigation results and conducts a calculating example, indicating that the proposed seismic damage prediction method for lining structures based on the SEDR principle can precisely and accurately predict the crack positions and expansion directions, which can provide a reference for the research on the damage mechanism of tunnels
Summary
As an important part of lifeline engineering, tunnel and underground engineering faces challenges in avoiding highintensity seismic zones due to line requirements. erefore, a tunnel may be severely damaged and difficult to repair if the tunnel is struck by a strong earthquake, even leading to extreme property losses and casualties. Shock and Vibration of the existing research methods of the damage mechanism of tunnel structures, experimental analyses and numerical simulations all use the principle based on stress and strain [13,14,15]. Combining with the Mohr–Coulomb slip principle, the crack positions and expansion directions of lining structures can be predicted by analysing the strain energy density ratios of the lining elements. This paper compares the numerical simulation results with the field investigation results and conducts a calculating example, indicating that the proposed seismic damage prediction method for lining structures based on the SEDR principle can precisely and accurately predict the crack positions and expansion directions, which can provide a reference for the research on the damage mechanism of tunnels.
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