Secant Piles Support Access Shafts for Tunnel Crossing in Difficult Geologic Conditions

A new 84-inch water pipeline project for Tampa Bay Water included a tunnel section under the Alafia River in Riverview, FL. Access shafts were required on each side of the river for the pressure-balanced tunnel boring machine. Since the 70 ft. deep access shafts extended roughly 25 ft. into the confined Florida Aquifer (Tampa Limestone) under an artesian head, control of groundwater flows was a serious concern. Two circular cofferdams (one 40 ft. and one 24 ft. ID) were designed and built for these access shafts. Alternating, overlapping hard/soft secant piles (36 inch diameter) were utilized to act as a lateral cutoff wall. Circular concrete compression ring walers were constructed to support the secant piles at five (5) levels. In order to maintain bottom stability and to control bottom water inflows, a pressure relief well system was installed at each cofferdam. The smaller cofferdam was instrumented with an inclinometer in one of the secant piles to monitor lateral deflections. In addition, vibrating wire strain gages were installed in the concrete ring walers to measure compressive strains and the resulting stresses during the excavation process.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0784407134
• Supplemental Notes:
  • Full conference proceedings available on CD-ROM.
• Corporate Authors:

  American Society of Civil Engineers

  1801 Alexander Bell Drive
  Reston, VA  United States  20191-4400
• Authors:
  • Anderson, Thomas C
• Conference:
  • GeoSupport 2004: Innovation and Cooperation in the Geo-Industry
  • Location: Orlando Florida, United States
  • Date: 2004-1-29 to 2004-1-31
• Publication Date: 2004

Language

• English

Media Info

• Media Type: Print
• Features: Figures; Photos; References;
• Pagination: pp 299-308
• Monograph Title: GeoSupport 2004. Drilled Shafts, Micropiling, Deep Mixing, Remedial Methods, and Specialty Foundation Systems

Subject/Index Terms

• TRT Terms: Access; Cofferdams; Excavation and tunneling; Inclinometers; Strain gages; Support piles; Tunnel shafts; Water pipelines
• Uncontrolled Terms: Access shafts; Compression rings; Secant piles
• Geographic Terms: Alafia River (Florida); Riverview (Florida)
• Subject Areas: Construction; Geotechnology; Pipelines;

Filing Info

• Accession Number: 01000143
• Record Type: Publication
• ISBN: 0784407134
• Files: TRIS
• Created Date: May 9 2005 9:46AM