Laboratory simulation of field preloading on Jizan sabkha soil

Jizan sabkha soil is characterized by being highly compressible with low bearing capacity. It cannot support a structure load without soil improvement. Preloading by embankment fill is one of the practical and economical methods to enhance the sabkha soil properties. Embankment fill of 3 m high with a pressure intensity of about 50 kPa is found to be adequate to achieve the required improvement. Simulation of preloading by laboratory consolidation test following a special loading sequence reasonably approximates the field settlement. The predicted settlement based on consolidation results is found to be close to the directly measured field settlement using the preloading technique. The pressure intensity and time of loading by embankment fill can be predicted by laboratory testing. In this research, the embankment preloading using a 3 m fill applied in two or three stages and sustained for about 6 months is found to be effective to improve the soft sabkha properties.