| 四川珙县下软上硬山岭地貌斜坡地震动响应特征 |
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| 引用本文： | 赵方彬,王运生,寇瑞斌,毕杨杨,向超.四川珙县下软上硬山岭地貌斜坡地震动响应特征[J].地质科技通报,2023,42(2):279-287. |
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| 作者姓名： | 赵方彬 王运生 寇瑞斌 毕杨杨 向超 |
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| 作者单位： | 成都理工大学地质灾害防治与地质环境保护国家重点实验室, 成都 610059 |
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| 基金项目： | 国家重点研发计划项目2017YFC1501000国家自然科学基金项目41877235国家创新研究群体科学基金项目41521002 |
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| 摘 要： | 强震中下软上硬坡体同震崩塌发育, 为了揭示这类坡体地震动的响应特征, 在珙县五同村安置了强震监测仪, 对斜坡表面和不同岩性的地震动响应进行监测, 并记录到不同方位、不同震中距的2次地震。研究表明: ①地震动响应规律有极强的方向性和距离性。2次地震相距监测站台的方向和距离不同, 使Ms 4.0级地震的峰值加速度和阿里亚斯强度反而比Ms 3.2级地震小。②0~30 Hz的地震波在低地山岭的高陡临空面附近有放大效应。1#监测点的主频小于3#与5#监测点, 3#监测点的主频最高。5#点的幅值范围为0.018~0.055 m/s-2, 3#点幅值范围为0.036~0.087 m/s-2, 3#点相较于5#点, 其三向最高幅值同比放大了1.58~2.0倍。③泥质砂岩的主频为4.8~8.4 Hz, 灰岩的主频为5.5~21.4 Hz, 不同的岩层共振频率不同, 灰岩对地震波的选频放大效应强于泥质砂岩。④地震波在不同高程的山岭斜坡部位具有选择放大作用, 在一定范围内高程越大地形放大效应越明显。
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| 关 键 词： | 珙县地震 斜坡地震动响应 地震方向效应 放大效应 山岭地貌斜坡 |
| 收稿时间： | 2021-08-17 |
Seismic dynamic response characteristics of the lower soft and upper hard mountain slopes in Gongxian,Sichuan |
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| Affiliation: | State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China |
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| Abstract: | The coseismic collapse of lower soft and upper hard slopes develops during strong earthquakes. To reveal the response characteristics of such slopes under dynamic loads, a strong-earthquake monitor was installed in Wutong Village, Gongxian County, to collect the slope surface and the ground motion with respect to different lithologies, and two earthquakes with different azimuths and epicentral distances were also recorded. Research shows that: ①The response law of ground motion has strong directivity and distance. The two earthquakes are in different directions and distances from the monitoring station, making the peak acceleration and Arias intensity of the Ms 4.0 earthquake smaller than those of the Ms 3.2 earthquake. ②The 0-30 Hz seismic wave has an amplification effect near the high and steep open surface of the lowland mountains. The main frequency of monitoring point No.1 is lower than that of monitoring points No.3 and No.5, and the main frequency of monitoring point No.3 is the highest. The amplitude range of point No.5 is 0.018-0.055 m/s-2, while the amplitude range of point No.3 is 0.036-0.087 m/s-2. Compared with point No.5, point No.3 has the highest three-way amplitude magnified by 1.58-2.0 times year-on-year. ③The dominant frequency of argillaceous sandstone is 4.8-8.4 Hz, and the dominant frequency of limestone is 5.5-21.4. Different rock formations have different resonance frequencies. The frequency-selective amplification effect of limestone on seismic waves is stronger than that of argillaceous sandstone. ④Seismic waves have a selective amplification effect on mountain slopes with different elevations. The larger the elevation within a certain range, the more obvious the terrain amplification effect is. |
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