STUDY OF CLAY SHALE SLOPES ALONG THE PANAMA CANAL. REPORT 3: ENGINEERING ANALYSES OF SLIDES AND STRENGTH PROPERTIES OF CLAY SHALES ALONG THE GAILLARD CUT

The results of the engineering studies and analyses which provide guidance on shear strength parameters applicable to the stability evaluation of existing slopes along the Gaillard Cut, the effects of future modifications, and evaluation of newly excavated slopes in clay shales are summarized in this report. During the field engineering investigations of 1969-1972, 128 undisturbed 6-in.-diam core samples of clay shales were obtained for laboratory testing from 10 boring at 9 sites along the Gaillard Cut. The site were selected to supplement without duplicating the planned work of the Bank Stability Surveillance Program (BSSP) by the Panama Canal Company (PCC). Thirty-one piezometers and eight slope indicators were installed to monitor pore water pressures with depth, determine groundwater conditions, and detect slide movements. Material properties determined in the laboratory provided information on index properties, consolidation characteristics, and shear strength for the Culebra, Cucaracha, and La Boca formation. Existing shear strength data for the Cucaracha, Culebra, La Boca, and Las Cascadas formation and the Pedro Miguel agglomerate are incorporated, and comparisons are made for each formation. Slope stability analyses of 98 past slides at 64 locations provided estimated shear strengths required for initial slides and reactived slides during and after construction in the Cucaracha, Culebra, La Boca, and Las Cascadas formations and Pedro Miguel agglomerate. Comparisons are made with shear strengths from laboratory tests. Four active slopes investigated in the field were analyzed in detail to provide shear strength required for stability under existing conditions. Valuable engineering information on surface crack patterns, blockage depths of bore holes, surface movements, rainfall data, and groundwater levels was furnished by PCC from their files and current BSSP activities. This report presents engineering data on present groundwater conditions and piezometric levels (Appendix A) and characteristics of materials (Appendix B), particularly on shear strength of clay shales in the Gaillard But. These data are integrated with results of analyses of past slides (Appendix C) and active slopes (Appendix D) to provide information on appropriate shear strengths for use in evaluating the stability of existing canal slopes. Dredging records and hydrographic survey data (Appendix E) were studied to determine their applicability as additional aids in predicting slope stability. Detailed information provided is intended to be useful in the design and evaluation of slopes in clay shale materials. Pertinent comments on the usefulness of the engineering field measurements are included where appropriate. Important results and conclusions are presented in Report 4, which summarizes the overall study.

  • Corporate Authors:

    U.S. Army Waterways Experiment Station

    3909 Halls Ferry Road
    Vicksburg, MS  USA  39180-6199
  • Authors:
    • Banks, D C
    • Strohm Jr, W E
    • De Angulo, M
    • Lutton, R J
  • Publication Date: 1975-6

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 550 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00099892
  • Record Type: Publication
  • Report/Paper Numbers: S-70-9
  • Files: TRIS
  • Created Date: Sep 30 1975 12:00AM