SWELLING BEHAVIOR OF CALCAREOUS CLAYS FROM THE EASTERN PROVINCE OF SAUDI-ARABIA

The development of heave and swelling pressure in the natural calcareo us expansive soils in the Eastern Province of Saudi Arabia causes majo r damage to structures constructed on or in them. The behaviour of exp ansive soil depends on the predominant type of clay minerals present, the cementing agents that bind these clay minerals and other physical and chemical properties. This paper presents the problems and the geot echnical and physicochemical properties of the calcareous expansive so il deposits in the Eastern Province of Saudi Arabia. X-ray, thermal an d chemical analyses and scanning electron microscopy were used to esti mate the type and quantity of clay and non-clay minerals and fabric of the investigated soil. The swelling potential was determined using a conventional oedometer test. A field test conducted for measurement of heave was compared with heave estimated from laboratory tests. Result s showed that the investigated soil had moderate to very high swelling potential and the heave estimated from the suction method was very cl ose to the value measured from the field test.