The construction of highways in the rugged Tihama Range of mountains in southwest Saudi Arabia presents special problems because of the steep cliffs, deep ravines, and unstable ground that has to be traversed. Ret-Ser Engineering Agency, of Taipei, Republic of China, spent six years building roads in the area, and developed a number of technological innovations which were described in a paper presented at the 10th IRF World Meeting in Rio de Janeiro, Brazil, in October 1984. Arthur Y. Chen, Vice President of Ret-Ser, discussedt he geographic terrain and its importance in the development of Saudi Arabia. The construction of the highways known as "Descents" starting from the plateau at the top of the escarpment and passing along steep cliffs and deep ravines to the coastal plain became an important and necessary task in the development of the road network. The work is characterized by the enormous amount of rock excavation, the interconnecting series of tunnels and galleries, high piered bridges, and the extensive need for high cuts and slope protection for the roads. In some stretches it was virtually impossible to employ heavy equipment for the start of the excavation process due to the inacessible locations. Working crews, suspended by ropes, were lowered down the cliffs where they used hand drills and small blasting charges to create ledges on which crawler mounted drills and bulldozers could be placed. Before blasting was carried out, rock nails were installed in adjacent areas to prevent sliding due to vibration. After the blasting, in weathered or heavily crushed areas, high-pressure gunite cladding, together fully-grouted rock nails, were used to reinforce the slopes. The shotcrete forced itself into the cracks and formed a continuous protective skin which effectively fastened the loose rock together, and the rock nails strengthened the rock friction resistance to stop the occurrence of any movement. Rock anchors up to nine meters in length were used too stabilize high cut areas. (Author)

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  • Accession Number: 00395424
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 31 1986 12:00AM