Water‐Entry Pressure and Friction Angle in an Artificially Synthesized Water‐Repellent Silty Soil

Abstract

Water‐repellent soils possess unique hydraulic and mechanical behaviors that confer large potential for their use in geotechnical applications because particle‐scale surface‐wettability characteristics significantly influence macroscale manifestations. This study examined the hydraulic and mechanical behavior of an artificially created water‐repellent silty soil with four different concentrations of a reactive organo‐silane solution. A series of laboratory tests was performed that included measurements of water‐droplet penetration time (WDPT), water‐entry pressure (WEP), flow rate, and friction angle. Experimental results showed that the artificial treatment produced a unique range of porosity values depending on the concentration and that the WDPT and WEP increased with decreasing porosity and increasing concentration. A gravimetric fraction of 40% water‐repellent particles was sufficient for bulk soils to exhibit water repellency. The flow rate of specimens with a high concentration of reactive organo‐silane tended to be high due to the resulting high degree of saturation on water permeation. In contrast, friction angles tended to decrease with increasing concentration of organo‐silane solution under dry conditions and remained quasi‐constant on wetting, regardless of the degree of saturation.