Effect of Adding Fine Gravel and Cement on Settlement of Sabkha Soil

Abstract

Sabkha soil is one of the many types of collapsible soils and in turn is on of themany types of problematic soils. This soil is totally having good engineeringproperties when dry ,i.e ,moderately bearing capacity with low settlement .But onceare wetted they loose their entire structure (collapse) and undergo very largeinstantaneous settlement .A laboratory model test consists of a cylindrical steelcontainer of 270mm diameter and 300mm height, the soil is brought from Al-Khalisdiscrete .The density of soil is controlled by placing the required weight inside thecontainer of known volume, to the required height .A square footing 60x60mm makesfrom steel is used .The stress is applied from a fixed loading system designedespecially for model tests .In this study two types of treatment carried out ,the firsttreatment is added fine gravel only with percentages (2%,4.5%,6%) to soil which isnot give good improvement .The second type of improvement is added 3% of cementwith fine gravel (4.5%,6%) percentages which give good improvement, reduced thecollapsibility to 84% .Also, when adding 3% of cement with 4.5% fine gravel to soil,give good improvement, reduced the collapsibility to 90% .