Abstract
To clarify how to arrive at earthquake ground motion parameters for use in evaluating the high rockfill dams during seismic loading conditions, as well as to evaluate reasonably the seismic response of dams subjected to strong earthquake, the differences of design response spectra determined by scenario earthquake and uniform hazard spectra theory are investigated in detail. Coupled with the safety evaluation of the Houziyan concrete-faced rockfill dam (CFRD) with a height of 200 m located in meizoseismal regions, comprehensive comparisons of key safety evaluation indices are performed using input motions determined from the abovementioned two design response spectra. The key safety evaluation indices include dynamic response acceleration, permanent deformation, safety of the impervious body, safety factor, and sliding displacement of the potential failure sliding body. Additionally, the ultimate seismic capability of the high CFRD is discussed based on the two response spectra. More considerable results can be achieved and offered to the engineers for the seismic design. It is obvious that the uniform hazard spectra, which are used to adopt in the safety evaluation of high CFRD, typically result in conservative evaluations and unnecessary economic cost for seismic design and reinforcements.
Highlights
For large-scale hydraulic buildings located in areas with high seismicity, the scientific and reasonable determination of the design response spectrum is directly related to the success or failure of the seismic design and reinforcements
Based on the requirements of the newly issued “Code for seismic design of hydraulic structures of hydropower project: NB 35047-2015” in China, the UHS and site-related response spectrum based on scenario earthquake was determined for the 223.5 m-high Houziyan concrete-faced rockfill dam (CFRD) using the seismic risk analysis methods
Based on the above results, the peak acceleration was adjusted to 0.50, 0.55, and 0.60 g, using acceleration-time curves based on the UHS and site-related response spectrum based on scenario earthquake. e ultimate seismic capacity of the Houziyan CFRD was studied by core evaluation indices such as the stability of slopes, permanent deformation of the dam, and impervious body safety [24,25,26]
Summary
For large-scale hydraulic buildings located in areas with high seismicity, the scientific and reasonable determination of the design response spectrum is directly related to the success or failure of the seismic design and reinforcements. In China, the newly issued “Code for seismic hydraulic design structures of hydropower project: NB 35047-2015” [14] states that the safety evaluation of hydraulic dams with a height above 150 m and basic intensity above VII must be conducted based on the site-related response spectrum using the scenario earthquake. The specific effect of the input motion parameters—which differ whether based on UHS or site-related response spectrum based on the scenario earthquake—on the dynamic response characteristics of the dam is not clear. Several key safety evaluation indices, including response acceleration, permanent deformation, safety of impervious body, safety factor, sliding displacement of potential failure sliding body, and ultimate seismic capacity, are evaluated and compared based on the two input motion parameters determined by UHS and siterelated response spectrum based on the scenario earthquake.
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