Oedometer Testing

The use of the oedometer test to measure swelling has a distinct advantage over other tests because the testing equipment is commonly available, and most geotechnical engineers are familiar with the testing methods. For expansive soils two basic types of oedometer tests are commonly performed. The most common type is the consolidation-swell (CS) test, in which the sample is initially subjected to a prescribed vertical stress in the oedometer, and inundated under that vertical stress. The constant volume (CV) test is another common method of test. In this test the sample is initially subjected to a prescribed vertical stress, but during inundation the sample is confined from swelling and the stress that is required to prevent swell is measured. The chapter discusses the factors affecting CS test data and a review of the current testing procedures based on observations and research performed by the authors.