Electrokinetic enhancement of microbial induced calcite precipitation used in improving the shear strength of soft clay

Abstract

In recent years, and from the principle of sustainable development to reduce chemical pollution, researchers around the world have begun to use microorganisms to induce the precipitation of calcium carbonate which is a biological ground improvement method that has been successfully used to improve sandy soil. Also, the electrokinetic method is a soil improvement technique without excavation, unlike traditional methods. In this study, MICP and electrokinetic techniques were used to improve the geotechnical properties of soft clay. A large bench scale will be used for this purpose. The test model was using graphite electrodes with a voltage gradient of 50 V/m. This study was carried out in two phases. The first phase included using a concentration of prepared Bacillus sonorensis 12×10-7 cfu while the second phase was 1×10-4 cfu for cementation reagent (0.25M, 0.5M, and 1M) during the period of treatment for each phase. The results showed the following. precipitation of calcite was considered to be the main reason causing a significant increase in shear strength by about (600- 1350%) for Bacillus sonorensis 1×10-4 and (800-2000%) for Bacillus sonorensis 12×10-7 cfu.