A STUDY OF THE COMPOSITION AND DENSITY OF SLURRY FOR STABILITY OF TRENCHES

Abstract

The techniques of stabilization of excavations by clay . suspensions have developed rapidly during the last 15 years. However, the mechanism by which the clay slurry stabilizes such excavations is not completely understood. The stability of circular excavations can be explained adequately by the hydrostatic pressure of the slurry and arching in the soil. With the application to rectangu-lar excavations, in particular continuous trenches, the hydro-static pressure of the slurry w~,s found insufficient in certain cases, to stabilize the trenches according to classical earth pressure theory. Consequently other stabilizing mechanisms mere proposed to account for this discrepancy1. Slurries are suspensions which are thix,.tropic. They have the property of becoming fluid on agitation and of settling to a. gel when left undisturbed. Thixotropic suspensions can be made from a variety of materials but the cheapest and the one used very frequently universally is bentonite....