深覆盖土层地震反应分析中的若干问题

以上海地区土层地震反应分析为例,讨论了深覆盖土层地震反应分析中的几个典型问题.如土层下卧缓倾角基岩面的影响,土层中假想基岩面的合理性问题,基岩波速对土层地震反应的影响,以及土介质动力特性的影响等.通过数值计算,得出了以下主要结论:下卧基岩面不大于2°的缓倾角影响可以忽略不计,假想基岩面会带来很大的计算误差,坚硬基岩的弹性对土层地震反应的影响很有限,应重视工程场地土介质动力特性参数的现场勘测.

Some Problems in Seismic Response Analysis of Soil Layer with Deep Deposit

Several typical problems in the seismic response analysis of soil layer with deep deposit have been discussed according to the seismic response analysis of the soil layer in Shanghai region.These problems include the effect of the inclination of the bedrock under the soil layer on the seismic responses of soil layer,the rationality of the artificial bedrock boundary in the soil layer,the effect of the wave velocity of the bedrock and dynamic characteristics of the soil media on the seismic responses of soil layer.Significant conclusions are reached through numerical analysis.In the seismic response analysis,the effect of angle of inclination of the rock surface under the soil layer can be neglected if the angle is not more than two degrees.The significant error will be introduced in the calculation when the rock surface is assumed in the soil layer.The elastics of the solid rock has little influence on the seismic response of the deep soil layer.The field investigation for the soil dynamic property should be devoted much attention to.