Test research on the influence of seismic wave frequency on the dynamic response of a layered rock slope
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摘要: 利用振动台模型试验探讨反倾层状岩质边坡的动力响应规律，通过输入不同频率、激振强度、持时的正弦波，监测模型边坡的加速度响应，着重分析频率对模型边坡加速度动力响应特性的影响。试验结果表明：①地震波频率对模型边坡动力响应的影响有两种不同的表现形式。当输入波频率小于等于模型边坡自振频率时，随着频率的增大，模型边坡的高程放大效应增强。②当输入波频率大于模型边坡自振频率时，随着频率的增大，模型边坡的高程放大效应减弱甚至消失。模型边坡的动力响应随高程的增加经历先减小后增大的变化趋势；模型边坡底部的加速度响应相对增强，甚至大于中上部响应强度；模型边坡各点的加速度放大系数基本小于1.0。③频率小于等于模型边坡自振频率的地震波往往造成模型边坡顶部和浅表部的变形破坏，频率大于模型边坡自振频率的地震波则造成模型边坡底部的变形破坏。④频率、激振强度、持时均对模型边坡的动力响应产生影响，但频率的影响最为显著，激振强度次之，持时的影响最弱。Abstract: The dynamic response of an anti-dip layered rock slope is examined by using shake table model tests. By inputting sine waves of different frequencies, excitation intensity and holding time, the acceleration of response of the model slope is monitored, and the influence of frequency on the dynamic response characteristics of acceleration of the model slope is analyzed emphatically. The results show that ① there are two different forms of the influence of frequency of seismic wave on dynamic response of the model slope. When frequency of the input wave is less than or equal to the natural frequency of the model slope, with the increasing frequency, the elevation amplification effect of the model slope is enhanced. ② When frequency of the input wave is greater than the natural frequency of the model slope, with the increasing frequency, the elevation amplification effect of the model slope is weakened or even disappears. The dynamic response of the model slope decreases first and then increases with the increasing the elevation. The acceleration response at the bottom of the model slope is relatively stronger, even greater than the response intensity of the upper and middle parts. The acceleration magnification factor at each point of the model slope is almost all less than 1.0. ③ The wave whose frequency is less than or equal to the natural frequency often causes deformation and failure of the top and superficial parts of the model slope and the wave whose frequency is greater than the natural frequency causes the deformation of the bottom of the model slope. ④ Frequency, excitation intensity and holding time have an influence on the dynamic response of the model slope, but the frequency has the most significant impact, followed by the intensity of vibration, and the impact of holding time is the weakest.
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Key words:
- shaking table test /
- rock slope /
- frequency /
- dynamic response /
- acceleration magnification factor
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