Laboratory investigation of liquefaction mitigation in silty sand using nanoparticles

• The effectiveness of laponite in liquefaction mitigation of silty soil is verified.
• The mechanisms of laponite mitigation of liquefaction potential are analyzed.
• The “thinning behavior” of laponite suspension affects the liquefaction characteristics.
• Dry mixing affects the microstructure characteristics of laponite–silty sand mixtures.
• The effects of laponite concentration and curing time on liquefaction resistance differ.

Nanomaterials are presented in this paper as a novel method of liquefaction mitigation that overcomes the limitations of traditional mitigation methods. The proposed method is different from traditional densification and chemical grouting methods: no ground disturbance occurs and an entire site can be treated. In this study, laponite, synthetic silicate nanoparticles that are nontoxic, pure, highly plastic, and smaller in size than natural clay particles, has been selected as a representative nanomaterial that can be used in conjunction with liquefiable silty sand. Little research has been undertaken on the mixing of such materials. The cyclic behavior and liquefaction resistance of mixtures of laponite and silty sand have been studied by means of dynamic triaxial tests. The pore pressure accumulation process and deformation properties are compared between pure silty sand and laponite–silty sand samples to verify the effect of laponite on the liquefaction mitigation of the silty sand. Additionally, the viscosity of laponite suspensions is measured to determine the appropriate gel time for curing the laponite–silty sand samples. Microstructural imaging with a scanning electron microscope is analyzed in conjunction with liquefaction mitigation mechanisms. Then the effects of laponite concentration and curing time on the liquefaction resistance of the treated samples are discussed. This work provides experimental data to support the beneficial effects of laponite mixing on the reduction of liquefaction susceptibility in saturated silty sand. It also assesses the mechanisms and effects of nanoparticles on liquefaction potential.