ENGINEERING WORK LEADING TO A ROCK TUNNEL PLAN

IN AN EFFORT TO PREVENT FUTURE CONTAMINATION OF LAKE MICHIGAN AND OTHER WATERWAYS FROM THE EXISTING COMBINED- SEWER SYSTEM, INVESTIGATIONS WERE CONDUCTED AND SEVERAL ALTERNATIVE PLANS SUBMITTED FOR DETAILED EVALUATION. THE PRELIMINARY INVESTIGATIONS INCLUDED DATA GATHERING, AND PROGRESSED THROUGH STUDIES OF HYDROLOGY, HYDRAULICS, ROCK MECHANICS, AND AQUIFER PROTECTION. ENGINEERING ECONOMICS AND FUNCTIONAL EFFICIENCY CONSIDERATIONS LED TO THE REOMMENDATION OF A PLAN FOR A NETWORK OF ROCK TUNNELS. THIS PLAN WILL INCLUDE 125 MILES OF ROCK TUNNELS UNDER THE WATERWAY SYSTEM, CENTRAL EXCAVATED SURFACE RESERVOIRS FROM WHICH THE MAIN BRANCHES RADIATE, AND DEWATERING TO THE EXISTING TREATMENT PLANTS DURING OFF-PEAK HOURS. THE TUNNELS, WHICH RANGE FROM 15 FT. TO 42 FT. IN DIAMETER, WILL BE LOCATED MAINLY IN THE SILURIAN DOLOMITE, AND FOR SHORT LENGTHS, IN THE MAQUOKETA SHALE. THEIR DEPTHS RANGE FROM 150 TO 300 FT. BELOW THE GROUND. THE STORAGE RESERVOIR WILL BE CONSTRUCTED IN LIMESTONE, WILL BE SEGMENTED, CONFINING THE MAJOR SETTLEMENTS TO ONE AREA, AND WILL BE AERATED TO MAINTAIN AEROBIC CONDITIONS (TO PREVENT OBJECTIONABLE O- DORS). THE TUNNELS WILL BE DEWATERED WITHIN TWO DAYS TO PRE- VENT SEPTIC CONDITIONS FROM DEVELOPING. A SUMMARY OF CON- STRUCTION COSTS WAS PREPARED AND IS PRESENTED IN TABULATED FORM. SALIENT FEATURES OF OTHER ALTERNATIVE PLANS ARE ALSO DISCUSSED.

Media Info

  • Features: Figures;
  • Pagination: p. 1051-61
  • Serial:
    • Volume: 2

Subject/Index Terms

Filing Info

  • Accession Number: 00236575
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 28 1974 12:00AM