Permanent Seismic Displacement Analysis

Presently, it is generally accepted by regulatory agencies in California that permanent seismic displacements along liner systems be limited to less than 6-12 inches. The permanent seismic displacement can be evaluate using the Hynes and Franklin (1984), Makdisi and Seed (1978) or Bray and Rathje (1997) charts (Figures 5, 6 and 7, respectively) which relate Ky/MHEA to displacement. Results obtained from these charts are conservative. If displacements approach 6 inches, computer modeling should be performed.

For this project, EBA used the program YSLIP_PM (Matasovic, 1997) to evaluate the permanent seismic displacement along the liner. The program calculates seismically-induced maximum permanent displacements by simulating the dynamic behavior of a rigid block on an inclined plane following the classical Newmark (1965) sliding block principles. Input parameters included Ky calculated from the stability analysis and the MHEA time history of the waste mass generated by D-MOD_2 in the site response analysis. For this project, the maximum permanent seismic displacement along the liner was estimated to be less than 6 inches.

A plot of Ky vs. displacement (Figure 8) is useful for evaluating the sensitivity of displacement to yield acceleration. Typically, a small change in yield acceleration results in a large change in displacement for calculated displacements greater than 6-12 inches, hence the reason for limiting displacements to under 12 inches. However, it may be argued that larger displacements are acceptable when failure is above the liner and does not compromise the integrity of the liner system.

References

• Bray, J.D. and Rathje, E.M., 1998, Earthquake-Induced Displacements of Solid-Waste Landfills, ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol. 124, issue 3, pg. 242-253.
• Hynes, M.E. and Franklin, A.G., 1984, Rationalizing the Seismic Coefficient Method, Miscellaneous Paper GL-84-13,U.S. Army Corps of Engineers Waterways Experimental Station, Vicksburg, Mississippi, 34 p.
• Makdisi, F.I. and Seed, H.B., 1978, Simplified Procedure for Estimating Dam and Embankment Earthquake-Induced Deformations, Journal of the Geotechnical Engineering Division, American Society of Civil Engineers, Vol. 104, No. GT7, July 1978.
• Matasovic, N., 1997, YSLIP_PM, A computer program for simulation of dynamic behavior of a rigid block on an inclined plane and calculation of permanent displacement of the block, April 1997.
• Newmark, N.M., 1965, Effects of Earthquakes on Dams and Embankments, Geotechnique 15, No. 2, pp. 139-160.

Toland Road Seismic Analysis - Table of Contents