Earthquake effect on the Tehran's Niyayeshtunnel

The effect of earthquake on Niayesh tunnel in Tehran city is investigated. First, by identifying the soil of the area, the amount of stress in the up, wall and bottom of the tunnel was calculated. Then, by using the acceleration data of large earthquakes that occurred in different directions of the tunnel construction, displacement and probable risk caused by earthquakes using PLAXIS software in three direct, static, quasi-static and dynamic modes after drilling, the tunnel was calculated. On average, this value was ۴۵.۶ mm on the surface of the earth. The values obtained in the dynamic state show that the movement of surface ground the area is restrained by the tunnel. The natural frequency for the Niayesh tunnel using Fourier spectrum calculations is ۵.۹۴ Hz for the building, which changes to ۵ Hz during an earthquake, and the period of the building is ۰.۱۶ seconds and ۲ seconds during an earthquake. These results are in applicable agreement with other results obtained in other underground spaces.