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CALCULATION OF A SPRAYED CONCRETE SUPPORT IN HYDRAULIC TUNNELS CONSTRUCTED IN WEAK ROCKS

An important characteristic of sprayed concrete is its bonding with the rock base, which results in joint operation of the lining-rock structure. Investigations to determine the bonding of sprayed concrete with various weak rocks showed that it reaches 0.5 minus 3.6 kg/sq cm and is determined mainly by the strength of the rocks themselves. The use of sprayed concrete linings in weak rocks can be recommended only on obtaining favorable results after conducting special comprehensive investigations. An equation to determine the average thickness of sprayed concrete is presented. The sequence for calculating the 2-layered support is outlined: the deisgn parameters of the support are assigned on the basis of practical experience, engineering geologic data, and technological considerations; the loads on the outer and inner layers of the support are determined; the thickness of the inner layer is determined as a single layered support with a strong bond between layers. If the calculated thickness of the inner layer differs considerably from the assigned thickness, appropriate corrections are made in the design of the support and a new thickness is assumed; the strength of the outer and then of hte inner layer of the support is checked for stability.

Media Info

  • Features: Figures; References;
  • Pagination: p. 860-863
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00157186
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 16 1978 12:00AM