DESIGN PRACTICES IN OVERCONSOLIDATED CLAYS OF NEW YORK

The key design practices for construction in overconsolidated clay deposits in New York State are summarized. The differences in prediction technology for heavily overconsolidated soils as compared with normally consolidated soils are highlighted. Rules of thumb for design practices are also included. The design approach used in based on the stress history of the deposit. Overconsolidated clays subject to overload-type stress history perform as predicted using classical approaches to settlement and stability. Clay deposits subjected to desiccated-type preconsolidation, however, require different approaches in exploration and modeling to properly predict performance. Continuous undisturbed samples are desirable, and many consolidation tests are needed to describe the preconsolidation history accurately. Plots of moisture content versus depth from numerous disturbed samples in the deposit best reflect the type of stress history and therefore are used as a guide to process selection. It is difficult to predict the probability of a slope failure for cuts in natural slopes. The slope stability varies with the rate of shear stress release and rate of water table drawdown. Cutslope failures in overconsolidated clays in New York commonly occur about 7 years after construction. Predictions of time for settlement for desiccated clays overlying normally consolidated clays are difficult to make. Therefore, treatment (such as wick drains) is recommended if the performance objectives cannot be guaranteed should settlement occur in a manner not predicted.

Language

  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 75-80
  • Monograph Title: Engineering properties and practice in overconsolidated clays
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00713478
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Nov 2 1995 12:00AM