The Mesopotamian Engineering researches..

Some Mechanical Properties of Sandy Gypseferous Soils In Rumaila – Khor Al-Zubair Area, Southern Iraq

Abdul-Mutalib Hasson Al-Marsoumi
Muhammad Jawad Kadhum*
Shema'a Khalid Kadhum

Dept. Geology, College of Science, Basrah University

*Dept. Civil Engineering, College of Engineering, Basrah University

Abstract

   Six gypseferous soil samples were collected from Rumaila to Khor Al-Zubair areas, Didibba Desert west of Basrah city, Southern Iraq. These soil are gypseous in nature with an average gypsum content of 15.5% W/w The mineralogical analyses revealed that they are consisting of quartz, gypsum, carbonate, and feldspar. The grain size analysis showed that the sand fraction form more than 80% of soil samples understudy. Several geotechnical properties were determined. The testing program comprises the determination of the effect of the different gypsum contents on the shear strength parameters; cohesion and internal friction angle of the gypseferous soils under consideration. Furthermore, the testing program exhibits the cohesion increases as gypsum contents increases up to 20% then decreases at 30%.  The results indicate that the improvement and deterioration of cohesion and shearing strength of soils are a result of the gypsum dual role, firstly bonding the soil particles, causing the and soil enhancement ( up to 20% added gypsum), and secondly causing the flocculation of  soil particles leading to the deterioration (More than 20% added gypsum) of  cohesion and shear strength of the gypseferous soils.