A Sustainable Hybrid Approach to Improve Footing Bearing Capacity Using EICP and Inclined Micropiles

This study investigates an innovative and sustainable hybrid approach combining enzyme-induced carbonate precipitation (EICP) with inclined micropile reinforcement systems for improving the soil bearing capacity of existing footings. The research evaluated two distinct EICP implementation methods across eleven experimental configurations, including three micropile inclination angles (90°, 105°, and 120°) for improving the bearing capacity of a square footing. The first method (method M1) involved injecting 150 mL of EICP solution through each of the eight perforated micropiles with a 21-day curing period, while the second method (method M2) employed staged injections around the footing totaling 1200 mL over two days with a 21–22-day curing period. Results demonstrated that the micropile-confined system combined with the EICP treatment significantly enhanced bearing capacity, with effectiveness increasing proportionally to pile inclination angles. While the EICP injection method M1 caused a 32% to 83% increase, method M2 exhibited 66% to 125% enhancement in bearing capacity for different micropile inclinations. Based on experimental validation, an analytical procedure was developed for predicting the bearing capacity of footings. This hybrid technique not only ensures structural effectiveness but also represents a sustainable, eco-friendly alternative to conventional ground improvement methods by reducing reliance on energy-intensive or chemically hazardous processes.