ROCK SLOPES AND BRIDGE FOUNDATIONS IN A FOLIATED ROCK MASS ALONG PORTIONS OF STATE ROUTE 69 NEAR MAYER, ARIZONA

Geologic units exposed in cuts in slopes and encountered in excavations for three new bridge sites across Big Bug Creek for the new alignment of State Route 69, just south of Mayer, Arizona consist of Precambrian metamorphic rocks of the Spud Mountain Volcanic and King Volcanic sequences. The sequences are composed primarily of an interfoliated and folded assemblage of phyllites and schists. These rocks generally possess good bearing capacities for structure foundations and have adequate strengths to support relatively steep slopes in cut areas. The stability of individual cut slopes is dependent upon the orientation of the discontinuities relative to the orientation of the cut slopes. Most of the slopes in the Mayer area support a 3/4:1 (horizontal/vertical) slope since the more persistent foliation joint set crosses the alignment of the new roadway and intersects the cut slopes at nearly 90 degrees. However, one failure occurred in the largest and southernmost cut slope during construction. This paper discusses the subsequent redesign of the slope to mitigate against further failures in this area and to remove the failed zone.

• Corporate Authors:

  Highway Geology Symposium

  North Carolina DOT, Geotechnical Unit, P.O. Box 3279
  Asheville, NC  United States  28802
• Authors:
  • Peterson, D E
  • Dahlen, K H
• Conference:
  • 49th Highway Geology Symposium
  • Location: Prescott, Arizona
  • Date: 1998-9-10 to 1998-9-14
• Publication Date: 1998

Language

• English

Media Info

• Features: Figures; Photos; References;
• Pagination: p. 39-51

Subject/Index Terms

• TRT Terms: Bearing capacity; Bedrock; Bridge foundations; Excavations; Fracture mechanics; Rock mechanics; Slope failure; Slope stability
• Subject Areas: Geotechnology; Highways; I43: Rock Mechanics;

Filing Info

• Accession Number: 00760773
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 9 1999 12:00AM