Nanomaterial-Enhanced Stabilization of Soft Clayey Soils: Optimal Content, Mechanical Performance, and Practical Frameworks

Soft clayey soils, characterized by low shear strength and high compressibility, present significant challenges for construction and infrastructure development. This review synthesizes current research on the application of nanomaterials such as nano-clay, nano-silica, and nano-Titanium dioxide (TiO₂) in enhancing the engineering performance of clayey soils. Emphasis is placed on identifying optimal nanomaterial contents and their corresponding effects on both mechanical and physical properties. Owing to their high surface-to-volume ratios and strong interparticle interaction potential, nanomaterials have demonstrated substantial improvements in soil stabilization, including increased compressive strength, reduced plasticity, and enhanced compaction characteristics. Experimental studies report optimal dosages ranging from 0.25% to 7% by dry soil weight, with notable enhancements often achieved at contents below 1%. Improvements are observed in key mechanical parameters such as cohesion, internal friction angle, and California Bearing Ratio (CBR), as well as in physical properties including liquid limit, plastic limit, and dry density. Nano-Silica, nano-clay, and nano-Titanium dioxide are particularly effective in reducing plasticity and increasing strength, while synergistic use with lime or other stabilizers yields further gains. The findings underscore the importance of tailoring nanomaterial type and dosage to specific soil conditions, thereby reducing reliance on trial-and-error approaches.