NUMERICAL SIMULATION OF PERVIOUS CONCRETE PILE IN LOOSE AND SILTY SAND AFTER TREATING WITH MICROBIALLY INDUCED CALCITE PRECIPITATION

Abstract

It is essential to provide a stable foundation system for construction projects to reduce the geotechnical risk of failure due to static or dynamic loads. Pile foundations are recommended to increase bearing capacity and decrease the dynamic oscillations of soils. Recently, soil stabilization using microbially induced calcite precipitation (MICP) was widely used to increase shear strength parameters and reduce the hydraulic conductivity of sand. In this study, the technique of using MICP was reviewed based on previous studies and analyzed using Plaxis 3D to evaluate the enhancement of a single pervious concrete pile under static, free vibration and earthquake stages of loose and silty sand. In the static stage, under the applying load to reach prescribed displacement of 76 mm, the results of loose sand demonstrate that the static load capacity was increased from 470 kN of untreated loose sand to 582, 598 and 612 kN after treating by MICP along the shaft and tip of a concrete pile with 0.5,0.75 and 1 m, respectively. In the earthquake stage, the result of treated loose sand such as vertical and lateral displacement was insignificant compared with untreated loose sand. The Plaxis 3D models have clarified the benefit of using MICP with the pile foundation model.