ULTIMATE SHAFT RESISTANCE OF TENSION PILE IN GYPSEOUS SOILS

Abstract

ABSTRACT Deep foundation such as piles adopt in case of weak soil or when type of soil in the site not capable to resists the external loadings from superstructure or collapsible soil. Types of external loads that the pile can sustain such as compression, tension or lateral load reflects on the design of pile and on the real behavior of soil-structure interaction. Many piles designed to resists compression loads only but in specific places such piles subjected to tension load due to lateral external loads such as wind or earthquake loadings. Another place that the piles subjected to tensile load is in case of the piles distributed under the towers, in this case not only sustain loads but also make the towers more stable. Many researchers investigated the behavior of piles embedded in sand or clay and subjected to axial and lateral loads, but little studies concerned on the behavior of pile in collapsible soils such as gypseous soil. This type of soil has capable to support the external load from superstructure in case of dry condition due to the existence of gypsum which strengthens the soil structure. Many problems appear when water flows through its particles due to the dissolution of gypsum inside the soil skeleton. This dissolution leads to form cavities in the soil structure and this causes many problems such as settlement, tilting, etc. for the structures.