Geotechnical properties of Kuwaiti “gatch” and their improvement

Due to the difficulties experienced with the so-called gatch soils, the Ministry of Public Works of Kuwait engaged the services of the firm DORSCH, Consulting Engineers of Munich, Germany, to study the properties of gatch and to recommend methods to improve its suitability for road construction. An investigation program was agreed upon and selected samples were obtained from Kuwait.Prior to the geotechnical tests, mineralogical analyses were carried out. Surprisingly they found no trace in the samples of gypsum which was believed to cause damage to the highways built on gatch. The geotechnical tests performed indicated that the gatch soils were very sensitive to moisture and were therefore unsuitable as highway construction materials. However, their properties could be improved by various stabilization methods. It was found that cement stabilization was the most promising method since it not only increased the bearing capacity of the soil but also reduced its swelling characteristics.