Improvement of Sabkha Soil by Using Geomesh and Addition of Polycoa

Abstract

Sabkha soil is a rich soil with salt deposited which result from evaporation ofwater, it is one of the many types of collapsible soils and in turn is one of the manytypes of problematic soils. This soil totally has good engineering properties when dry,i.e ,moderately bearing capacity with low settlement. But once is wetted it loses itsentire structure (collapse) and undergoes very large instantaneous settlement. Alaboratory model test consists of a cylindrical steel container of 270mm diameter and300mm height, the soil is brought from Al-Khalis discrete. The density of soil iscontrolled by placing the required weight inside the container of known volume, tothe required height. A square footing 40mmx40mm makes from steel is used. Thestress is applied from a fixed loading system designed especially for model tests.In this study two types of improvement are used , the first improvement consistsof fine geomesh under footing at different depth (0.5B,B,2B),the secondimprovement is the addition of polycoat with different concentration to surface of soil.The first method do not give good results of improvement but the second methodgives good improvement which reduces the collapsibility to 62% at stress level of50kPa.