Case Studies for Hydraulic Fracturing in Core of Earth and Rockfill Dams-A Review

Hydraulic fracturing has become one of the major problems in rock fill dams, since it plays a significant role in the initiation and extension of cracks in the clay core. There have been a number of well-studied cases in which dams have failed or been damaged by concentrated leaks for no apparent cause. In some of experiences, investigators concluded that differential settlement cracks were the probable causes, even though no cracks were seen on the surface. Hydraulic fracturing is generally considered as a key cause which may induce the leakage of the dam during first filling. The likelihood of the occurrence of hydraulic fracturing increases with increasing the water level or the crack depth. The lower part of the dam core is the zone in which the phenomenon of hydraulic fracturing may be induced easily. Hence it necessary that every precaution be taken against leakage to ensure safety of the dam. The investigating results indicate that hydraulic fracturing in earth and rockfill dams can be controlled and is helpful to reduce the likelihood of the occurrence of hydraulic fracturing by, increasing any of Young's Modulus, increasing the Poisson's Ratio and increasing the density of core soil