New Aspects of Soil Fracturing in Clay

A theoretical analysis using cavity expansion theory suggests that soil fracturing can occur within the plastic zone during expansion of a cavity in clay. Results from pore pressure measurements during pile driving and hydraulic fracturing tests support these theoretical conclusions. Practical consequences of soil fracturing are considered with respect to pile driving in clay, the efficiency of driven sand drains as well as field permeability tests. An analysis of the hydraulic fracturing tests for determination of in-situ stresses indicates that, in almost all cohesive soils, fracturing is likely to occur along vertical planes in both normally and overconsolidated clays.