Gypsum content horizontal and vertical distribution of an-Najaf and al-Kufa Cities' soil by using GIS

الملخص EN

An-Najaf province considered one of the most important cities in Iraq, which is facing a rapid population growth and continuous development in constructions such as housing, hotels, bridges and shopping malls.

Therefore, this study aims to create database for the gypsum content in An-Najaf province (Najaf center and Al-Kufa city).

To evaluate the spatial variability of gypsum content, 464 boreholes and in situ tests were selected and analyzed using Geographic Information System (GIS).

To achieve that, the adopted method consisted of four steps: (1) data collection; (2) geotechnical data georeferencing; (3) interpolation methods and (4) establishment of maps.

Nine geotechnical maps were produced for depths (0, 2, 4, 6, 8, 10, 12, 14, 16, and 35) m.

Results showed that the largest part of the study area for the depths from 0-4 m had a gypsum content ranged between 10-25% (moderately gypsiferous), whereas the depths from 4-8 m had a gypsum content ranged between 3-10% (slightly gypsiferous), and the depths from 8-35 m had a gypsum content ranged between 0.3-3% (very slightly gypsiferous).

This conclude that the layers from 0-4 m are exceeding the allowed limits (10% gypsum content), which may affect the stability of constructions due to the high levels of groundwater in Najaf province.