Hydraulic Pulldown Procedure for Collecting Large Soil Monoliths

Abstract

ABSTRACT SOIL monoliths 3-m (9.8-ft) square and 2.4-m (7.8-ft) deep were collected by hydraulically jacking bottomless steel boxes into a clay loam soil. Four jacking assemblies that utilized commercially availabe 178-kN (40,000-lb) hydraulic jacks were anchored to bell-bottomed piers at the corners of the steel boxes. A pulldown frame supported the jacking assemblies over the piers and uniformly distributed the pulldown force over the 9.5-mm (3/8-in.) thick walls of the steel boxes. Soil around the walls of the steel boxes was excavated as the boxes were jacked down. The procedure is a major advance in the collection of large soil monoliths. Bell-bottomed piers or similar anchors provide larger pulldown forces than are practical with deadweights, and hydraulic jacks or cylinders offer precise control of the downward movement. The technique is economically feasible for large soil monoliths, especially where the pulldown equipment can be reused to collect several monoliths.