九寨沟M_S3.2级余震薛家坝坡体地震动响应特征  

SEISMIC RESPONSE OF XUEJIABA SLOPE DURING THE JIUZHAIGOU M_S3.2

作　　者：辛聪聪 王运生[1,2] 申通[1,2] 赵波 洪艳[1,2] 韩立明 XIN Congcong;WANG Yunsheng;SHEN Tong;ZHAO Bo;HONG Yan;HAN Liming(State Key Laboratory of Geohazard and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059)

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059 [2]成都理工大学地球科学学院,成都610059

出　　处：《工程地质学报》2018年第6期1622-1630,共9页Journal of Engineering Geology

基　　金：国家创新研究群体科学基金(41521002);国家重点研发计划项目(2017YFC1501000);地质灾害防治与地质环境保护国家重点实验室自主课题基金(SKLGP2015Z001)资助

摘　　要：为研究余震对山体的地震动响应规律,在九寨沟薛家坝斜坡山体安装地震台阵,对斜坡表面以及斜坡内部不同深度地震动进行监测研究。M_S3. 2级余震触发了山脚及山顶4台强震记录仪,数据揭示:位于斜坡表面凸出位置的山体地形,地震的放大作用明显,同时水平向的加速度峰值大于垂直方向;对比山脚,斜坡表面2#-1监测点加速度峰值PGA最大,阿利亚斯强度值放大5倍以上,放大效应最大的方向在垂直向,加速度达到2. 48倍,阿利亚斯强度达到5. 24倍;随着向山体内部水平深度的加深高位放大效应逐渐衰减,PGA最大值由洞口2. 48下降到2. 03,阿利亚斯强度响应系数最大值由洞口5. 84下降到3. 92;自坡体表面水平向内,各监测点加速度峰值逐渐减小,在0～25 m内自坡表面向内加速度峰值下降最快,坡体内部下降幅度变小;傅氏谱表明,山脚的频率成分范围0～50 Hz,主频值大小为23 Hz左右,2#-1监测点频率范围较山脚未有明显变化,但主频值明显减小,在5 Hz上下;在斜坡上洞口傅氏谱频率成分复杂,随洞口向洞内水平加深,各监测点幅值及频率成分逐渐降低的趋势。研究表明,在地震作用下,随着加速度幅值的增大,地震动能量会呈几何倍数的增加,且山体表面是地震动能量最大的位置,若短时间振动能量超过岩体的强度,则会出现崩塌、滑坡,同时对工程建设的安全有极大的影响。In order to research the seismic response laws of a mountain at different depths of a slope,a seismic monitoring array was installed in the Xuejiaba slope of Jiuzhaigou county. Four monitoring instruments at the foot and top of the mountain were triggered by a MS3.2 aftershock. The data reveal the following feature. The terrain of the hill,which is located at the protruding position on the surface of the slope,has obvious amplification effect. At the same time,the horizontal acceleration peak is greater than the vertical direction. Comparing with the another monitoring at the foot of the mountain,the PGA at the 2^#-1 monitoring point on the surface of slope is maximum. Its arias intensity enlarges more than five times. The largest amplification effect is obvious in the vertical direction.The acceleration is 2.48 times and the alias intensity is 5.24 times. The amplification effect of acceleration at each monitoring gradually attenuates with the deepening of the horizontal depth of the mountain. The value of PGA decreases from 2.48 to the inner of 2.03,and the Alias intensity is reduced from 5.84 to 3.92. The peak acceleration decreases greatly within the surface range of 0 to 25 m and at the inner slope falls at a slow rate. Fourier spectrum indications the following features. The frequency range get from the foot of mountains is 0-50 Hz. The main frequency value is about 23 Hz. The frequency range of the 2^#- 1 monitoring point has not changed significantly compared with the data from the foot of the mountain. But the main frequency value is obviously reduced about 5 Hz. Spectral frequency components are complex,with the depth of the hole deeper in horizontal direction,the amplitude and frequency components of each monitoring point gradually decrease. Through the analysis of all of the data,it is confirmed that under the earthquake,with the increasing of the amplitude of acceleration,the energy of the ground vibration can increase geometrically,and the surface of the mountain can be the most powerful position. I

关 键 词：地震动响应 薛家坝 放大效应 加速度反应谱 

分 类 号：P642.27[天文地球—工程地质学]