Rockfall hazards assessment along the Aswan–Cairo highway, Sohag Governorate, Upper Egypt

Abstract

The geotechnical evaluation of rockfall hazards along the Aswan–Cairo highway, Sohag Governorate, Upper Egypt has been achieved throughout a variety of field investigations and lab tests on the slopes and rock cut faces of Lower Eocene Plateau limestone. The studied Aswan–Cairo highway is located in a mountainous area and surrounded on both sides by highly sheared limestone plateau possesses steep slopes and swelling clayey hosted bands. The clayey bands are characterized by highly swelling potentiality that considered as instability and weakness planes along which the limestone blocks will be downward fallen. Based on slope height and angle, the studied slopes are mostly considered instable. Kinematically, the Lower Eocene limestone blocks have planer and wedge failure modes. According to the estimated values of the coverage distance and rebound amplitude, ditches must be dug (2 m width and 1.5 m depth) to reduce the rebound amplitude height of falling blocks and catch these blocks to avoid them to reach the highway toe. Ditches can be filled with sands to will absorb the falling blocks kinetic energy as well as rockfall barrier must be constructed at the most hazards sites to retain the falling blocks away from the road toe.