Analytical Study to Assessment the Stability of the Al-Askarian Underpass in Najaf

Abstract

This study studied the most important problems that may be exposed to the Al-Askarian underpass in the province of Najaf. The length of the tunnel is 507 m. It is divided into two parts according to the number of test pits, and each part is divided into 17 parts depending on the locations of the joints in the tunnel. During the construction process, the problem of height-water level appeared at the construction site, so four wells were drilled to control the groundwater level. The highest groundwater level was recorded at a depth of 1 m below the ground level. The analytical study showed that the stability of the origin, depending on the safety factor, is as follows: Safety coefficient against overturning from 3.5 to 10.4. Safety coefficient against sliding from 1.23 to 25.6. Safety coefficient against bearing capacity from 6.4 to 108.7. Calculations were also made to find out the resistance of the tunnel against the ascending forces in the event that the groundwater level rises to the ground level and to suggest appropriate treatments for such a case.