1. Researcher, Dept. of Highway and Transportation, College of Engineering, Al-Mustansiriya Univ., Baghdad, Iraq.
2. Researcher, Chair of Foundation Engineering, Soil and Rock Mechanics, Ruhr-Univ. Bochum, Laboratory of Foundation Engineering, Soil and Rock Mechanics, Universitätsstr. 150, 44780 Bochum, Germany (corresponding author).
3. Senior Lecturer, Geoenvironmental Research Centre, School of Engineering, Cardiff Univ., Newport Rd., Cardiff, Wales CF24 3AA, U.K.
4. Professor, Chair of Foundation Engineering, Soil and Rock Mechanics, Ruhr-Univ. Bochum, Universitätsstr. 150, 44780 Bochum, Germany.