The capillary pull of an ideal soil

Abstract

1. The capillary pull of an ideal soil has been determined by measuring the maximum hydrostatic pressure (H) sustainable by a liquid surface formed, amongst an assemblage of uniform spheres of mean diameter 0·0374 cm. (2a). It has been found that using liquids of low surface tension like benzene to avoid contamination, the constant K in the equation H_gp = KT/2a has the weighted value 9·5.2. Values of K for single apertures between three and four spheres in contact have been determined, using steel spheres of a diameter ⅛ in. and benzene. It is found that K does not vary rapidly for four spheres and has a value between 9 and 10 for apertures in which the ratio of breadth to length varies between 1·0 and 0·4.3. The equivalent capillary tube is the circular or elliptic cylinder touching the spheres forming the aperture. This assumption gives values of K in fair agreement with observation.4. The value of K is practically independent of variations of pore-space ranging from 36 per cent, to 40 per cent, such as usually occur in ordinary packing.