Reinforcement of silty soil with permeable polyurethane by penetration injection

Abstract

Injection of silts is commonly used to improve unfavorable engineering properties. Though the effects of traditional grouting materials on soil improvement have been investigated in recent years, documented research studies on the macro-, micro-level characteristics and engineering application of problematic silt solidified by polyurethane are fairly limited. This study examined the characteristics and application of silt with permeable polyurethane. Micro-level physico-chemical bonding mechanisms were studied. Unconfined compressive strength (UCS) and anti-permeability tests were performed. The UCS increased from 0.2 to 1.2 MPa; their permeability was smaller compared to the untreated soils. Microstructural changes in the soil fabric showed that polyurethane modified the consolidated silt’s porous network. Drilling process monitoring and the high-density electrical method were used for evaluation. The soil resistivity increased from 120 to 300 Ω·m; drilling speed decreased by over 29%. Thus, permeable polyurethane improves an embankment’s compaction degree and mechanical properties.