Deep Soil Mixing Method for the Bio-cement by Means of Bender Element Test

Abstract

This article presented the effect of mixing patterns for the bio-cement in two different soils (Kaolin clay and Bangkok sand). Bio-cementation process initiated the crystal forms of calcium carbonate (CaCO₃) to bind the soil particles. Soil samples were mixed with the solution containing 250 mM of CO(NH₂)₂, 250 mM of Ca²⁺ (by CaCl₂) and 20% (v/v) of urease. In simulated deep mixing of Kaolin clay, the research found that blades used in solution mixing affected the strength development of Kaolin clay after bio-cementation. The V _s of 210 m s⁻¹ was found in comb blade mixer. In simulated deep mixing of Bangkok sand, the research found that solution injecting method affected the V _s of Bangkok sand. The period drop and the period injecting methods provided better V _s results than the one time pouring and the continuous injecting methods.