EFFECT OF SOME CHEMICAL ADDITIVES ON THE BEHAVIOR OF SABKHA SOIL

Abstract

The presence of salts in soil may cause severe problems to structures constructed on it, because of the high dissolution of salt particles when subjected to water from any source. The primary objective of this study is to investigate the behavior of single footing over different percentages of sabkha soil (5%, 10%, 20%, and 40%). A laboratory model, manufactured locally was used for this study. The sabkha soil is prepared by mixing ordinary soil with specified quantities of sodium chloride salt to have different percentages of salinity. The footing used is a 75mm diameter circular steel plate and 20mm thickness and holds fixed stress, with the aid of a loading frame which in turn is attached to a firm table. Dial gauges are attached to the fixed table and placed on the footing, to record settlement with time. The study includes also the effect of cement and lime addition with different percentages(1%, 3%, and 5%), on the collapsibility of sabkha soil. Mixing sabkha soil with 5% of cement will reduce collapse potential (S/B%)* upon wetting, by 97%. While mixing sabkha soil with 3% lime will reduce collapse settlement by 47%, On the other hand, mixing sabkha soil with 1% cement slurry increases the collapsibility by 3%. This study also shines the light on the effect of compaction on the properties of sabkha soil. The collapse potential (S/B%)* was reduced by 50% when increasing the compaction of sabkha soil model from 17.7 to 19 kN/m³.