-Ahwaz urban railway project, line 1, Amberg Engineering Ltd. (2015).
-B.Arabzade, (1386). Geotechnical report of Ahvaz city train line 1. (in persian).
-Shiau, J., & Al-Asadi, F. (2020). Three-Dimensional Heading Stability of Twin Circular Tunnels. Geotechnical and Geological Engineering, 38(3), 2973–2988.
doi.org/10.1007/s10706-020-01201-z
-Shiau, J., & Al-Asadi, F. (2021). Twin Tunnels Stability Factors Fc, Fs and Fγ. Geotechnical and Geological Engineering, 39(1), 335–345.
doi.org/10.1007/s10706-020-01495-z
-Sloan, S. W. (1988). Lower bound limit analysis using finite elements and linear programming. International Journal for Numerical and Analytical Methods in Geomechanics, 12(1),61–77. doi.org/10.1002/nag.1610120105
-Sloan, S. W. (1989). Upper Bound Limit Analysis Using Finite. International Journal for Numerical and Analytical, 13 (November 1987), 263–282.
doi/10.1002/nag.1610130304/full