- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
This paper studies the seismic behaviour of tunnels that are damaged during aftershocks. The tunnels were made from three different materials that had different flexural rigidity. An undamaged tunnel was constructed out of one material, while the damaged tunnels were built with the other two materials. The seismic load was applied with a unidirectional shake table. The peak ground acceleration for various input motions varied from 0.1 g to 1.2 g. The dynamic earth pressure around the tunnel was measured using three soil pressure transducers. The tunnel was placed in the transverse direction of shake table motion. The properties of the surrounding soils were calculated from bender element. The peak dynamic stress generated in the soil was used to study the behaviour of the damaged tunnels. A hand-held vibration analyser was used to measure the motion of the shake table. The results show that the damaged tunnel is more vulnerable to low frequency seismic motion.
This paper studied the seismic behaviour of damaged tunnels. It was observed that the damage tunnel is subject to much higher dynamic stress than the undamaged tunnel. Also, lower frequency aftershocks can be more devastating in some conditions. Predominant horizontal dynamic stress frequencies increase with increased input motion frequencies for rigid tunnels. In flexible tunnels, horizontal dynamic stress frequencies do not change much with changes in input frequency. Dynamic stress amplitude is much larger for the flexible tunnel compared to the rigid tunnel. Dynamic stresses in soil away from the tunnel are greater for damaged tunnels compared with undamaged tunnels. Also, it does not depend on the degree of damage. However, a more detailed study of damaged tunnel behaviours during an earthquake should be conducted. The inside deformation of the tunnel is an important parameter that must be considered to ensure serviceability of underground spaces. Finally, the appropriate non-linear numerical model can be developed to simulate damaged tunnels seismic behaviour.