Abstract
Potential earthquake-induced damage to overlapped tunnels probably occurs during the operation and maintenance of mountain tunnel engineering, especially in the seismically active zone. This study investigated the dynamic response and the failure characteristics of the parallel overlapped tunnel under seismic loadings by employing shaking table tests. The failure mode of the parallel overlapped tunnels was analyzed through macroscopic test phenomena. The dynamic responses of the surrounding rock and tunnel lining were evaluated by acceleration and dynamic strain, respectively. In particular, wavelet packets were used to investigate the spectrum characteristics of the tunnel structure in depth. The failure process of the model can be divided into three stages. The upper-span and the under-crossing tunnels showed different failure characteristics. Additionally, the lining damage on the outer surface of the tunnel mainly occurred on the right side arch waist and the left side wall, whereas the lining damage on the inner surface of the tunnel mainly appeared on the crown and invert. Wavelet packet energy results showed that the energy characteristic distributions of the upper-span and the under-crossing tunnels were not consistent. Specifically, the energy eigenvalues of the crown of the upper-span tunnel and the invert of the under-crossing tunnel were the largest, which should be considered to be the weak parts in the seismic design.
Highlights
Earthquakes and rainfall are two important factors often considered in the studies of engineering structure stability [1, 2], and the structural dynamic response caused by earthquakes has been paid more attention. e overlapped tunnel has been widely used in engineering because of the limitation of terrain and route selection [3]
Since the response spectrum of the El-Centro seismic wave is in good agreement with the design response spectrum of the Chinese seismic code (Code for seismic design of buildings GB500112010), the El-Centro seismic wave was selected as the input wave for the shaking table test
When the amplitude of the seismic wave is 0.1g, there is no crack around the spatial parallel overlapped tunnel and the slope surface
Summary
Earthquakes and rainfall are two important factors often considered in the studies of engineering structure stability [1, 2], and the structural dynamic response caused by earthquakes has been paid more attention. e overlapped tunnel has been widely used in engineering because of the limitation of terrain and route selection [3]. Earthquakes and rainfall are two important factors often considered in the studies of engineering structure stability [1, 2], and the structural dynamic response caused by earthquakes has been paid more attention. As the traffic arteries pass through complex mountainous areas, more overlapped tunnels are built-in high-intensity earthquake areas, which often face the problems of earthquake damage [6]. Erefore, it is necessary to study the seismic response of overlapping tunnels in high-intensity earthquake areas. Some scholars have analyzed the mechanical characteristics and stability of the surrounding rock of the cross tunnel with a small clear distance through different numerical software; Shock and Vibration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
