论文部分内容阅读
采用基于小波变换的多向地震动速度脉冲特性鉴定方法,从NGA(next generation attenuation)数据库及汶川地震动记录中选取196条速度脉冲地震动;基于Newmark非耦合滑动模型,考虑土体动力非线性,通过对比近断层脉冲及非脉冲地震动引起的不同参数边坡的滑移特征,分析近断层地震动速度脉冲特性及边坡本身参数对滑动位移值的影响;同时对近断层速度脉冲地震动参数与边坡滑移量的相关性做了对比分析。结果表明:(1)近断层速度脉冲地震动引起的边坡滑动位移值远大于近断层非脉冲地震动,对长周期边坡影响尤为明显;(2)相比非脉冲地震动,脉冲地震动引起的边坡滑动时间较短,且主要发生在地震动起始阶段的较短时间内(速度脉冲段),滑移的坡体具有更大的滑移速度,携带更高的能量,从而对周边环境产生更强的破坏作用;(3)近断层速度脉冲地震动引起的边坡滑移特征与其速度脉冲特性(持时短、周期长、速度峰值大)密切相关,且峰值地震动速度PGV与边坡滑移量具有高度相关性。最后,通过比较原始速度脉冲地震动及相应的等效脉冲作用下不同参数边坡的滑动位移值,对提取出的等效脉冲预测原始地震动引起的滑动位移的有效性进行分析,并基于此建立脉冲参数–滑动位移曲面。
A total of 196 velocity impulsive ground motions were selected from NGA (next generation attenuation) database and Wenchuan ground motion records by using the method of multi-directional ground motion pulse characteristics identification based on wavelet transform. Based on the Newmark non-coupled slip model, By comparing the slip characteristics of slopes with different parameters caused by near-fault pulses and non-pulsating ground motions, the effects of near-fault ground motion velocity pulse characteristics and slope parameters on sliding displacement are analyzed. At the same time, the effects of near-fault velocity pulse ground motion The correlation between parameters and slope slip is analyzed. The results show that: (1) Slope slip displacement caused by near-fault pulse ground motion is much larger than that of near-fault non-pulse ground motion, especially for long-period slope; (2) Compared with non-pulse ground motion, The slope slip caused by the slope is relatively short, and mainly occurs in a short period of time (velocity pulse) in the initial stage of ground motion. The slipping slope has greater slip speed and carries higher energy, (3) The characteristics of slope slip caused by near-fault pulse ground motion are closely related to its velocity pulse characteristics (short duration, long period and large velocity peak), and the peak ground motion velocity PGV It has a high correlation with slope slip. Finally, by comparing the sliding displacement values of different parameters of the original velocity pulse and the corresponding equivalent pulses, the validity of the predicted equivalent slip to predict the initial displacement due to ground motion is analyzed. Based on this, Establish pulse parameters - sliding displacement surface.