Stabilizing fine sand by adding clay: Laboratory wind tunnel study

Abstract

Summary Because of the need to develop inexpensive technology to stabilize highly erodible soils and arrest migrating sand dunes, this research was undertaken. Our objective was to evaluate the effectiveness of adding clay to very sandy soil to reduce wind erosion susceptibility. The study was conducted in a laboratory wind tunnel facility. In the first part of the study, various amounts of bentonite and kaolinite clay were added to a fine sand. The mixtures were wetted with simulated rain, and resulting aggregates were tested for mechanical stability. The aggregates' resistance to crushing increased greatly with increasing clay content. Because the bentonite was several times more effective than kaolinite, bentonite was used in the second part of the study. Trays were filled with various concentrations of bentonite-sand mixtures, wetted with simulated rain, dried, and tested in the wind tunnel with and without abrader at a free stream wind speed of 14 m s -1. Without abrader (wind only), the soil loss increased with clay concentration. With an abrader of sand introduced into ISSN 0933-3630 @1990 by CATENA VERLAG, D-3302 Cremlingen-Destedt, W. Germany 0933-3630/90/5011851/US$ 2.00 + 0.25 the wind tunnel upwind of the test section, cumulative soil loss from the tray with the untreated sample was 20 and 30 times more than that from the trays treated with 10 or 20 g bentonite per kg of sand. Wind erosion susceptibility of sandy soil was reduced greatly by adding small amounts of bentonite clay in this laboratory study.