Structural Grouting of Oroville Dam Coreblock

Abstract

A 290,000 cu yd concrete coreblock, a foundation structure for the impervious core of the 770-ft high Oroville Dame earth-fill embankment, was damaged by excessive deformations induced by embankment loads during construction. Structural cracking, more than 500 ft in length and with width varying from 1/4-in. to 6-in. impaired the hydraulic and structural performance of the coreblock. An exploratory core drilling operation and structural grouting program is described, including mix design and testing, grouting equipment and grouting performance. Over 6,000 bags of cement were injected in various grout mixes in several, continuous grouting operations to fill the cracks. Hydraulic plugging of an impaired drainage gallery was accomplished by intrusion grouting of preplaced gravel. Repairs were successfully carried out by the grouting program, and excellent hydraulic performance of the coreblock has been realized over the 8 yrs since the subsequent completion of embankment construction and reservoir filling. /Author/