Abstract
The standard for Probabilistic Safety Assessment of Nuclear Power Plant on earthquakes published by Atomic Energy Society of Japan in 2007 states that the effect of uncertainy of soil properties on the earthquake response of subsurface layers should be assessed with conducting monte-carlo simulations of equivalent linear analysis. This paper presents a fundamental study on the effect of uncertainty of dynamic soil properties on the earthquake response with equivalent linear approach. A series of monte-carlo simulations of earthquake response analysis of a simple one-dimensional soil layer model have been conducted, where uncertainty of initial shear modulus G0, strain dependency of G/G0-γ and h-γ are considered. Through a series of simulations, it is demonstrated that although the average of maximum response of the subsurface top layer increases as input earthquake motion increases, the coefficient of variance of them does not necessarily increases, and thatG/G0-γ relationship is the most influential factor among the concerned parameters. And also, it is shown that the maximum response of ground surface plotted against the peak frequency of the frequency response function calculated with equivalent linear analysis under converged condition, distributes around the response spectrum curve of the input earthquake motion so that the maximum response can be roughly estimated from the response spectrum curve. Finally, applicability of two-point-estimate technique is examined with being compared with monte-carlo simulation results.
