Seismic Design, Analysis, and Remedial Measures to Improve Stability of Existing Earth Dams

摘要

This report discusses the seismic design of new embankment dams and analysis of existing dams, and possible courses of action to mitigate seismic hazards in the event that analysis indicates unsatisfactory conditions. Also discussed are the use of pseudostatic stability analysis and appropriate seismic coefficients. Several courses of action to deal with unsatisfactory conditions have been identified as being potentially feasible. These actions are designed either to reduce the risk of failure or to assure that the consequences will be tolerable should a damaging earthquake occur near an existing dam judged susceptible to earthquake-induced liquefaction. An essential condition is that the accomplishment and the effects of the proposed remedial work be verifiable. Courses of action discussed include (a) no action, (b) regulation to public access downstream, (c) partial lowering of the pool, (d) permanent emptying of the reservoir, (e) in situ densification of the foundation, (f) surcharge, (g) dewattering, (h) reduction in the drainage paths, (i) grouting, (j) construction of a replacement structure, (k) replacement in a new location, and (l) construction of a detention dam.