الفهرس | Only 14 pages are availabe for public view |
Abstract High density electrical prospecting has been widely used in ground water investigations, civil engineering and environmental surveys. The present study aims to know sequence of layers (especially clay) and its properties which will create many problems in the buildings which will be constructed in the study area. Ten vertical electrical soundings (VES) were carried out to cover the area under the study. Res1D program has been used to interpret the observed data. Moreover, a comparison between drilled well data and the resistivity interpreted showed four geo-electric layers: the surface layer corresponding to gravel and sand with resistivity from 342 to 3700 ohm.m, the second layer with resistivity from 4 to 200 ohm.m corresponding to hard clay, the third layer with resistivity from 1 to 110 ohm.m corresponding to sticky clay and the fourth layer with resistivity from 1 to 78 ohm.m corresponding to sandy clay. The computer software, Surfer, was used to construct: resistivity sections with lengths of 2500, 900 and 1000 m, resistivity maps at different depths, and iso-thickness maps for the surface layer and clay layers. The result of inspection of the iso-thickness maps for the surface layer and clay layers showed that, the thickness of the surface layer started from 0.5 m and reached to 10 m and thickness of the clay layers started from 3 m to 29.5 m and there depth started at 0.5 m approximately. Laboratory tests for clay samples from the study area showed a liquid limit (LL) from 56 to 67 %, a plastic limit (PL) from 38 to 42 %, and free swelling (FS) from 110 to 140 % which is one of the expected causes of cracks in the buildings which will be constructed. |