Role of MICP treatment area in mitigating liquefaction-induced settlements for shallow foundation

Microbially Induced Calcite Precipitation (MICP) is an effective ground improvement technique for mitigating liquefaction-induced ground deformations. However, limited research has explored its application for reducing shallow foundation settlement in liquefiable soils. Understanding the extent of the area requiring MICP treatment beneath a foundation is critical to minimizing settlement. This study aims to evaluate the impact of the improvement area of MICP-treated blocks on mitigating liquefaction-induced settlements of shallow foundations using a series of 1 g shake table model tests. The dimensions of the treated blocks were determined based on the Boussinesq load distribution chart and treated to achieve a shear wave velocity of 250 m/s. Scaled shake table tests were conducted, modeled after a large-scale shake table experiment. The testing setup included three soil layers with different relative densities, with a shallow foundation placed on the surface crust. MICP-treated blocks of varying sizes were placed beneath the foundation. The results demonstrated that when the MICP-treated block was configured as either L×B×1.25B or 1.5 L×1.5B×B - where L and B are the length and width of the foundation - resulted in substantial improvements, with reductions of 80% in foundation settlement and 98% in foundation tilting. Notably, the L×B×1.25B configuration achieved performance similar to the 1.5 L×1.5B×B , while reducing the treated volume by 44%. Furthermore, the results emphasize the importance of optimizing the MICP-treated area to effectively mitigate liquefaction, providing valuable insights into the practical application of MICP for improving the performance of shallow foundations in liquefiable soils.