Bearing Capacity of Bored Pile Model Constructed in Gypseous Soil

Abstract

Gypseous soils are distributed in many regions in the world including Iraq, which cover more than (31%) of the surface area of the country. Existence of these soils, always with high gypsum content, caused difficult problems to the buildings and strategic projects due to dissolution and leaching of the gypsum caused by the action of water flow through soil mass. For the study, the gypseous soil was brought from Bahr Al-Najaf, Al-Najaf Governorate which is located in the middle of Iraq. The model pile was embedded in gypseous soil with 42% gypsum content. Compression axial model pile load tests have been carried out for model pile embedded in gypseous soil at initial degree of saturation of (7%) before and after soil saturation. Several criteria have been used to calculate the bearing capacity of the model bored pile through the results of the pile load tests. It was found that Shen's method gave almost an acceptable result for all model pile load tests. Large draw down in bearing capacity was observed when model pile has been loaded after it was subjected to soaking for (24) hours because of loss of cementing action of gypsum by wetting.