The incorporation of environmentally friendly stabilizers into deep soil mixing (DSM) as partial replacements for ordinary Portland cement (OPC) offers significant potential for sustainable geotechnical applications. This study presents a comprehensive investigation into the mechanical performance of soft clay stabilized with OPC, ground granulated blast-furnace slag (GGBS), and Terrazyme using a novel contra-rotational shear DSM (CS-DSM) technique, which enables improvements in large-diameter deep soil stabilization and superior mechanical outcomes through the use of a self-developed bidirectional mixing rig, enhanced drilling efficiency, and intelligent construction control. Extensive field and laboratory tests demonstrated that the CS-DSM method produces high-quality columns with improved uniformity and integrity in OPC–Terrazyme and OPC–Terrazyme–GGBS systems. Substantial enhancements were observed in unconfined compressive strength, ultrasonic pulse velocity, and bearing capacity when Terrazyme and GGBS were incorporated, attributable to their acceleration of hydration and pozzolanic reactions. A linear relationship (R2=0.84) between strength and pulse velocity confirmed the feasibility of velocity-based assessment for in-situ pile performance. Furthermore, microstructural analysis via computed tomography scanning revealed a more uniform pore structure and reduced porosity, contributing to the observed mechanical improvements. The findings highlight the effectiveness of CS-DSM and the synergistic benefits of OPC, Terrazyme, and GGBS for sustainable, high-performance soil stabilization.
Shi et al. (Thu,) studied this question.