ISSN 1003-8035 CN 11-2852/P

    基于地脉动观测的花岗岩风化壳边坡结构探查与动力响应研究以浙江丽水某滑坡为例

    Investigation of the structure and dynamic response of granite weathering crust slopes based on microtremor recordings: A case study of a landslide in Lishui, Zhejiang Province

    • 摘要: 花岗岩风化壳边坡在我国东南地区广泛分布,极易在降雨条件下发生群发性滑坡,因此,花岗岩风化壳边坡结构探查和动力响应研究对此类地质灾害防治具有重要的意义。文章以浙江丽水某降雨诱发的花岗岩风化壳滑坡为例,于2019年7月滑坡发生后开展现场调查,结果表明该边坡由粗粒花岗岩风化层和花岗闪长岩风化层组成;2024年11月开展边坡地脉动监测,基于地脉动HVSR法的分析表明边坡坡顶、坡腰、坡脚的卓越频率不同,基于HVSR法的边坡剪切波速反演结果表明边坡由外向内主要由花岗岩风化残积层、全-强-中风化层组成,存在2~3个可能演化为滑面的地下界面,边坡在坡向方位上具有最显著的放大效应,且随高程的增大,3~22 Hz内竖直向和4~60 Hz水平向放大效应显著增强,各台站间同频率上存在放大同步现象,这不利于动力荷载作用下边坡的稳定,但跨频率间放大不同步,这有利于动力荷载作用下边坡的稳定性。

       

      Abstract: Granite weathering crust slopes are widely distributed in southeastern China and are highly susceptible to mass landslides during rainy events. Investigating the structure of granite weathering crust slopes and studying the dynamic responses of these slopes are crucial for preventing and mitigating such geological disasters. This paper examines a landslide in Lishui, Zhejiang Province, with field investigations conducted in July 2019 immediately following the landslide event. The results indicate that the slope consists of a coarse-grained granite weathering layer and a granodiorite weathering layer. In November 2024, subsequent microtremor monitoring was carried out on the slope. Utilizing the horizontal-to-vertical spectral ratio (HVSR) method, the anlaysis identified distinct predominant frequencies at the top, middle, and base of the slope. Shear wave velocity inversion based on the HVSR method showed that from the exterior to the interior, the slope mainly consists of granite weathered residual soil layers and fully to moderately weathered layers, with 2 to 3 potential underground interfaces that could evolve into sliding surfaces. The slope exhibits the most significant amplification effect in the direction of the slope, and as the elevation increases, the amplification effects significantly intensify within the 3 to 22 Hz vertically and 4~60 Hz horizontally, with synchronization of amplification at the same frequencies across different stations, which is detrimental to the slope stability under dynamic loading. However, the asynchronization of amplification across different frequencies is beneficial to the stability of the slope under dynamic loading.

       

    /

    返回文章
    返回