COMPARATIVE-STUDY ON PHYSICAL TESTS OF DISPERSIBILITY OF SOILS USED FOR EARTHFILL DAMS IN TURKEY

Use of dispersive clays in earthfill dams causes serious problems that may be difficult to solve later unless this type of soil is adequatel y defined and properly used. The problems may occur suddenly and cause catastrophic failures. In many countries, such problems have resulted in dam incidents or failures attributed to dispersive soils. This pap er briefly presents tests to determine the dispersibility properties o f soils and discusses their limitations as shown by the comparative st udy on crumb and pinhole tests. The study was based on test results of 352 samples belonging to 29 different projects currently under planni ng and design stages in Turkey. As a result of this study, it can be s tated that the results of pinhole tests mainly confirm those of crumb tests, while some index tests do not provide a more reliable way to id entify dispersive soils.