疏水土阻水性能及评价方法研究OA

Water infiltration and migration in soils are major contributors to geotechnical engineering hazards such as roadbed frost heave and slope instability.As a novel material with excellent performance characteristics,hydrophobic soil offers a promising approach to addressing these issues.To evaluate the water-resisting capacity of hydrophobic soil,this study prepared a hydrophobic soil using Qinghai silty clay and a new hydrophobic additive.A series of experiments—including water droplet penetration tests,immersion tests,breakthrough pressure tests,and nuclear magnetic resonance(NMR)tests—were conducted to systematically investigate the wetting properties,breakthrough pressure,long-term stability,and pore water distribution characteristics of the material.The results indicate that:(1)The water repellency of hydrophobic soil increases with both additive content and compaction degree.The optimal hydrophobic additive content for Qinghai silty clay is 15.5％.(2)Under long-term immersion,the water content-time relationship of hydrophobic soil follows a power function.The infiltration rate gradually decreases and approaches zero,with the final saturation degree stabilizing at approximately 0.2.(3)At the optimal additive content of 15.5％and compaction degree of 0.95,the breakthrough pressure of hydrophobic soil is about 40 kPa.Breakthrough pressure is negatively correlated with pore size and positively correlated with contact angle.(4)After long-term immersion,the pore water content of hydrophobic soil is about 80％lower than that of ordinary soil.Pore water in hydrophobic soil consists mainly of capillary water,accompanied by adsorbed water,distributed in two pore size ranges:0.01～0.1 μm and 1～4 μm,respectively.This study provides a reference for evaluating the water-resisting performance and supporting the engineering application of hydrophobic soils.