Earthquake Engineering Support, Phase 4
Final rept. Phase 4
STEEDMAN (R S) READING (UNITED KINGDOM)
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This report describes the initial findings of an experimental study supported by the U.S. Army Centrifuge Research Center and Engineer Earthquake Engineering Research Program EQEN into the behavior of saturated sands under high initial effective confining stresses subjected to strong ground shaking. The research was conducted using the Army Centrifuge at the U.S. Army Engineering Research and Development Center ERDC, located in Vicksburg MS, formerly known as the Waterways Experiment Station WES. The centrifuge studies have shown that the generation of excess pore pressure is limited to a level less than 100 percent for vertical effective confining stresses exceeding around 3 atmospheres atm, or 300 KPa. This limit reduces at higher confining stresses. It is likely that this limit is a function of a range of variables, including amplitude of shaking. A second key finding indicates that dense layers overlying loose layers may still be readily liquefied as a consequence of the high excess pore pressures generated below. If verified, the potential benefits from these findings for the design of remediation works for large earth dams could be substantial. The report describes the equipment used for the experiments, the research program, and presents the initial results, contrasting the development of excess pore pressure at low confining stress with that at high confining stress. Possible consequences for a hypothetical dam are discussed.