CYCLIC SHEAR STRENGTH OF VARIABLY CEMENTED SANDS

The Vincentown Formation of New Jersey is a stratigraphic unit of Tertiary Age within the New Jersey Coastal Plain. Initial laboratory test results of the Vincentown Formation indicated an appreciable difference in cyclic strengths between undisturbed and reconstituted samples. In addition, many samples showed very high cyclic shear strengths, although the relative densities were comparably low. Because these properties are not normally associated with consolidated or unconsolidated sands, a detailed laboratory and field study was conducted. The purpose of the study was to evaluate the in situ physical state of the sands and relate these results to the dynamic properties which were obtained in the laboratory. The properties of the Vincentown Formation, a cemented silty fine to medium sand, was studied by means of field observations and laboratory triaxial CIUC tests and cyclic triaxial liquefaction tests. In addition, petrographic analyses of the Vincentown Formation was conducted to explore the mineralogy and physical properties of the sedimentation and to evaluate to what extent diagenetic processes have affected these initially unconsolidated Coastal Plain sediments. The results indicate that the apparent anomolous strength properties observed in both static and dynamic tests are clearly attributable to the inherent structure of the formation which was controlled by the manner of deposition of both the sediments and subsequent calcareous cementation. Traditional methods of evaluating cyclic shear strengths need to be reevaluated when applied to cemented soils. In addition, it was found the care must be exercised in sample selection for soils of this type to minimize disturbance effect as test results are sensitive to the sampling method used in the field study. /Author/

Media Info

  • Features: Figures; References;
  • Pagination: p. 819-835

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Filing Info

  • Accession Number: 00179782
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Oct 12 1978 12:00AM