The Earthquake Engineering Online Archive

Cyclic behavior of dense coarse-grained materials in relation to the seismic stability of dams

Banerjee, Nani G.; Seed, H. Bolton; Chan, Clarence K.

UCB/EERC-79/13, Earthquake Engineering Research Center, University of California, Berkeley, 1979-06, 283 pages (480.2/B25/1979)

The report presents the results of a comprehensive cyclic triaxial test program conducted on a modeled rockfill material with the intent of simulating as closely as possible the field loading conditions developed during an earthquake on a coarse-grained soil. Gradation with 2-in. maximum particle size was used for the 12-in. diameter specimens tested. Necessary design modifications were incorporated in the test facilities to accommodate a wide range of test pressures. Sustained pressure tests, conducted to simulate the aging effect in a prototype structure showed very significant increases in cyclic resistance in a relatively short period of 2 1/2 months when compared to data for normally consolidated samples tested immediately after compaction. After correcting the basic test data for aging effects, the test results were reduced to a usable form for performing a seismic stability analysis of the 770-ft-high Oroville gravel-fill dam in California for a magnitude 6.5 earthquake which might possibly occur near the dam and also for a hypothetical earthquake of magnitude 8 1/4 occurring on a fault close to the dam. The analyses showed that the anticipated permanent deformations of the dam caused by earthquakes of magnitudes in the range 6.5 to 8.25 would be acceptable. These findings, however, do not preclude the possibility of surface raveling of loose gravel near the crest--a phenomenon which is not considered of great significance from a structural integrity point of view.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-79-13.pdf (59 MB)