Determination of Bearing Capacity of the Soil Using Cross-Hole Seismic Survey for a Water Treatment Plant, Thi Qar, Southern Iraq

Abstract

The geophysical method (Cross-Hole Survey) was used to assess the bearing capacity of the soil in the study area to build a water treatment plant. It was noted, that the velocities of the primary and secondary waves decrease at the depths of 4 and 5 meters compared to the depths above and down, so, the lithology or physical properties of this specific soil have changed. It was also observed that seismic wave velocities are low in general due to the medium density and hardness of the soils in the study area. Furthermore, the elasticity modulus values were shown to decrease at depths of 4 and 5 meters. It is further evidence of the soil's weakness at these depths. When the type of layer changed, the elastic modulus changed as well. The geotechnical properties between the wells were evaluated based on the velocities of seismic waves (S-waves and P-waves) for classifying the load capacity values with the stiffness. The bearing capability of the soil was found to be medium-stiff at depths of 2 and 3 meters, but soft at depths of 4 and 5 meters. At depths of 6, 7, 8, 9, and 10 meters, the bearing capacity is stiff to very stiff.