The Mechanism of Raindrop Splash on Soil Surfaces1
- M. M. Al-Durrah and
- J. M. Bradford2
From the results of high-speed photography of 4.6-mm-diam drops impacting various soil materials and from soil mechanics principles, a new concept in describing the mechanism of soil detachment from raindrops impacting on saturated soil surfaces is proposed. The impulsive loading caused by the impacting drop does not permit time for drainage; thus there is no change in total soil volume or bulk density. The soil surface is deformed under the impulsive load application of the drop; however, the vertical strain under the impact area is compensated by a bulge around the perimeter of the depression. The vertical force of the drop is transformed to lateral shear caused by radial flow of the impacting drop. Splash angle is determined by the depth of the cavity and the size of the bulge surrounding it.
Splash angle was highly correlated with soil shear strength as measured by the fall-cone method. Low soil strength resulted in (i) a larger cavity and surrounding bulge, (ii) a greater detachment of soil particles due to the shear stress of the radial flow, and (iii) a greater splash angle with the horizon.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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