AN INVESTIGATION OF STRUCTURAL AND SOIL RESPONSES TO HAND- TUNNELLING PROCEDURES

THIS M.E. THESIS DISCUSSES THE BASIC CONCEPTS USED IN THE DESIGN OF TUNNEL LININGS, PUTTING EMPHASIS ON HAND-MINING PROCEDURES. IT INCLUDES A DISCUSSION OF SOIL AND STRUCTURE MOVEMENTS ASSOCIATED WITH THIS METHOD, AND A COMPARISON OF EXPECTED MOVEMENTS WITH THOSE THAT OCCURRED DURING THE CONSTRUCTION OF A HAND-MINED SECTION OF THE WASHINGTON, D.C., METRO PROJECT. IN THE DISCUSSION OF THE TUNNELLING PROJECT, AN ANALYSIS IS MADE OF THE RELATIONSHIP BETWEEN THE STRESS AND THE OVERBURDEN LOAD THAT OCCURRED IN THE TUNNEL SUPPORT SYSTEM. THROUGHOUT THE PAPER, THERE ARE BRIEF COMPARISONS OF THEORIES USED IN HAND-MINING VERSUS THOSE USED IN SHIELD-DRIVEN TUNNELS. IN MAKING THE POINT THAT DESIGN PROCEDURES SHOULD TAKE INTO CONSIDERATION THE AVAILABILITY OF THE ROCK STRENGTH IN THE DESIGN OF A STRUCTURE IN THE MIXED FACE CONDITION, THE AUTHOR NOTES THAT MOST PROCEDURES TODAY DESIGN CONSERVATIVELY, USING THE FULL OVERBURDEN IN THE CASE OF SHALLOW OR MODERATELY DEEP EARTH TUNNELS. THE PROCEDURE ALSO INCLUDES HYDROSTATIC PRESSURES THAT BUILD UP AFTER THE DEPRESSED WATER TABLE IS ALLOWED TO RETURN TO ITS ORIGINAL LEVEL. POSSIBLY, THE PRESENCE OF THE FIRM MATERIAL WOULD GIVE MORE ASSURANCE TO THE FACT THAT FULL OVERBURDEN PRESSURES NEED NOT BE USED. IT HAS BEEN PROVEN THEORETICALLY AND IN PRACTICE THAT "ARCHING" DOES OCCUR. IN THIS PARTICULAR CASE, THE STRAIN DIFFERENTIALS ARE LESSENED DUE TO THE DECREASED HEIGHT OF EARTH OVERBURDEN. THIS, IN TURN, DECREASES THE CORRESPONDING STRESS INDUCED IN THE "ARCHED" AREA.

  • Supplemental Notes:
    • APP
  • Corporate Authors:

    Howard University

    2600 6th Street, NW
    Washington, DC  USA  20059
  • Authors:
    • Evans, R N
  • Publication Date: 1972-8

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 107 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00236456
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 24 1973 12:00AM