Abstract: “Collapsible soils are located in aired and semi-arid regions around the world. Collapsible soils cause remarkable damage to overlying structures. To improve this soil type to allow building, it is necessary to create a compacted replacement top sand layer above this weak, compressible soil stratum to increase its bearing capacity, reduces displacement and changed soil behavior to brittle behavior. In this paper, the influence of using the same collapsing soil compacted at different compaction ratios as a replacement material with different thicknesses on collapse strains is studied using field plate load tests. The paper discusses the mechanisms of this system using a large-scale model footing for a case studies for a housing project in sixth of October city-Giza governorate- Egypt. That site has a collapsible silty sand soil. Circular plates of 750-mm diameter were employed in field tests. The load-settlement were modeled under dry conditions of soil at natural water content of 4% and”

Keywords: collapsible soil, soil bearing capacity, plate load test, soil improvement, in situ tests , and soil replacement