贵州开阳金钟牛赶冲崩积体特征研究

牛赶冲崩塌所在的开阳县金钟镇上洋水河矿区,受洋水背斜和NNE走向断裂的影响,区内陡崖呈带状分布。加之采矿活动强烈,磷矿层顶板白云岩陡崖易形成危岩带,近20a来先后发生大小崩塌数十起。本文研究的牛赶冲崩塌发生于2005年,崩积物在牛赶冲沟内呈条带状堆积,形成3个运动和堆积特征差异明显的区域,其崩落运动特征和崩积体分布特征颇具代表性。本文在堆积体特征野外调查分析的基础上,结合落石运动路径模拟,分析表明该崩积体一般以滚动的形式向沟内运动形成倒石堆,但个别大块落石受微地貌影响,沿靠近倒石堆右侧的一小冲沟运动,起初滚动,后为跳跃,各落点清晰可辨。文章最后综合已发生崩塌的运动特征和数值模拟,对危岩体未来失稳可能的危害范围做出了预测。     

贵州都匀马达岭滑坡运动特征研究

在暴雨触发作用下,2006年5月18日贵州都匀马达岭发生滑坡,滑体随即形成的碎屑流,充填了坡下长达1km的沟谷。滑坡堆积物在空间上有明显的分区特征,由上至下可分为滑源区、滑体堆积区、碎屑流流通区、碎屑流堆积区四个区域进行研究。在对马达岭滑坡进行详细野外调查的基础上,从滑坡的地形条件、堆积情况及运动特征等方面探讨滑坡的发生机理及运动过程,结果表明:马达岭滑坡为一高速远程滑坡,滑坡迅速启动并在特殊的破坏模式和地形条件下,形成了"一快一慢"两种不同的运动方式,即大块岩体"坐着"下伏流体的缓慢运移以及碰撞、铲刮形成的碎屑物质的高速抛飞。     

Characteristics and failure mechanism of landslides along highways triggered by 2021 Ms6.4 Yangbi earthquake

On May 21, 2021, at 21:48, the Ms6.4 Yangbi earthquake struck Dali prefecture, Yunnan province, China; the maximum PGA reached 714.78 gal, causing 37 casualties and infrastructures damage. A field investigation demonstrated that seismic landslides were concentrated along the G56 Hangrui and Dayangyun highways, classified as local rock falls and shear slides. The shear slides were more severe than the local rock falls and were located along the Dayangyun highway, which was still under construction when the earthquake occurred, severely impacting following engineering activities. Typical shear slides caused by the earthquake were selected for detailed investigations; electrical resistivity topography (ERT) was conducted to study the failure mechanism. The ERT results indicated that the sliding surface was located at the interface between the overburden layer and the underlying rock stratum. The slope failures along the Dayangyun highway were characterized by several tensile cracks on the rear edge, a relatively short displacement, and an accumulation at the toe of the excavated slope where reinforcement measures had not yet been completed. The combined effect of engineering activities and a geological structure provided favorable conditions for slope failure. In addition, seismic motion triggered the landslides; however, engineering activity was a specific and significant factor contributing to the shear slides during the Yangbi earthquake. Excavation and incomplete construction reduced the stability of the overburden soil layer. Although the scale of the seismic landslides in the Yangbi earthquake was generally small, the coming rainy season after the earthquake may contribute for sliding again.