REVIEW OF EXPANSIVE SOILS

The discusser describes the development of a small inexpensive oedometer in which undisturbed specimens are tested, first by measuring the swelling pressure, then by submitting the specimen to consolidation (shrinkage) and swelling cycles between preselected minimum and maximum pressures. The pressures adopted were 1/2 tonf/sq ft and 4 tonf/sq ft, representing average and minimum field figures for temperature to semi-arid climate. The limits can be varied and should perhaps be related to climatic rating. The soils are classified according to the actual amount of consolidation and the expansion they undergo between the applied stress limits. Based on field records, various foundation solutions have been suggested for different classifications. An advantage of this system which can be extended to pavements, is that only small undisturbed specimens are required and these can be obtained by hand methods if necessary. The oedometer is spring loaded and can be operated in a central laboratory or field office/laboratory. The classification system takes account of the possibility of shrinkage as well as swelling. Brittle structures, it is observed, are more susceptible to damage from doming associated with heave, as doming puts tensile stress into the upper parts of the walls. Shrinkage is more likely to cause dishing, throwing tensile stresses into the foundations which can resist these stresses.

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Filing Info

  • Accession Number: 00081413
  • Record Type: Publication
  • Report/Paper Numbers: Proc. Paper 11037
  • Files: TRIS
  • Created Date: Mar 26 1975 12:00AM