Geotechnical investigation and mapping of jazan city, ksa using gis

This paper deals with the geotechnical maps of Jazan city showing the physical and mechanical properties, hence, determine the bearing capacity of the soil in Jazan city and its extensions. Chemical properties of soil are used to identify the site's environmental conditions of soil at sites of Jazan city – Kingdom of Saudi Arabia (KSA). Geographic Information Systems (GIS) are used in geotechnical engineering applications, GIS can be utilized as a part of the geotechnical site investigation to create a site map. In this study paper the GIS is used to estimate the missing data of the Jazan city for geotechnical mapping. Also, GIS is used for information coordination, determining the Geotechnical area, analysis, investigation, and establishing the layout of Jazan geotechnical maps. The study area is located in the city of Jazan between the eastern border 42.653°E, 16.935°N and western border 42.353°E, 16.907°N has been selected as a case study. Data on the soil at sites are taken from 22 boreholes in Jazan city in order to carry out geotechnical investigations. Borehole logs are carried out in different locations in Jazan city such as Dehaga, Alshwajrah, Almagaria, and Almaaboj, geotechnical investigations have been recorded that water content in the soil is high on at the west part closed to the sea and is decreasing at north and south parts, but the water content is very low at the central part. The level of groundwater is up to 6 m above sea level in the western part of the study area and up to 0.5 m below the sea level at the study areas closed to the sea. The study showed that the soil in Jizan is silt, clay and sand soil. The study of mechanical properties of the soil showed that the soil of Jizan reaches cohesion of (c = 0.2 kg/ cm 2) and the angle of internal friction of soil reaches (Ф=31°). Accordingly, the unconfined compressive stress at failure (qu) is between 1.0 to 2.20 kg/cm.