2024 Volume 10 Issue 51 Pages 1918-1923
Innovative soil improvement methods like calcite-induced precipitation methods have been promising techniques in improving the shear strength of sand. EICP is an innovative bio-inspired approach that has emerged in recent years as an environmentally friendly solution for liquefaction countermeasures. EICP is a candid process to promote the calcium carbonate (CaCO3)/calcite precipitation obtained by mixing urea (CO(NH2)2), calcium chloride (CaCl2), and urease enzyme. Bio-cementation using EICP helps in the deposition of CaCO3 in the void space where clogging of the porous medium causes a reduction in porosity and hydraulic conductivity. All these factors increase the soil's strength, leading to soil liquefaction mitigation. In this study, poor-graded silica sand is adopted to evaluate liquefaction resistance. EICP solution consists of 3 g/l urease added with 1 M Urea and 0.67 M Calcium Chloride as cementation solution. The cyclic response under an effective confining pressure of 100 kPa in the pure sand and EICP-treated specimen in 7 days of curing time was studied. Field emission – Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS) revealed the deposition of calcium carbonate on the interparticle contacts and surface of the sand grains, which enhances the cyclic resistance in the soil.
