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工程科学与技术:2020,52(6):22-29
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平敞型高速远程滑坡碎屑流运动与堆积演化规律研究
(1.西南科技大学 环境与资源学院,四川 绵阳 621010;2.四川大学 水利水电学院,四川 成都 610065;3.四川大学 水力学与山区河流开发保护国家重点实验室,四川 成都 610065)
Debris Flow Movement and Accumulation Evolution of Flat Long-runout Landslide
(1.School of Southwest Univ. of Sci. and Technol., Mianyang 621010, China;2.College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China;3.State Key Lab. of Hydraulics and Mountain River Eng., Sichuan Univ., Chengdu 610065, China)
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投稿时间:2020-03-30    修订日期:2020-06-18
中文摘要: 尼续滑坡发育于藏南亚东-谷露裂谷带中段开阔的半地堑盆地边缘,滑坡物质堆积分布区为平坦河谷地貌,是青藏高原腹地发育的一处典型“平敞型”高速远程滑坡。该滑坡堆积区具有十分完整的堆积结构与典型碎屑流形态,研究该滑坡有助于揭示“平敞型”岩质高速碎屑流运动与堆积分异机制。本文通过对尼续滑坡及其堆积区各组成部分开展了详细地面调查,结合地球物理方法揭示了源区斜坡破坏基本特征与破坏机理,通过高分辨遥感解译与堆积物颗分试验揭示了滑体演化各阶段碎屑物质的空间展布规律。通过对尼续滑坡碎屑流堆积物质结构及空间形态演化特征的研究提出:“平敞型”高速碎屑流转化过程可划分为3个阶段,即在源区斜坡段的滑坡结构碎裂化阶段、中部滑动区的物质结构碎屑化阶段;前缘区域的碎屑流流态化运动与堆积阶段,相对应的滑体结构具有碎裂化-碎屑化-流态化的阶跃式转化过程,中部与前缘区域的碎屑流以内部或底部的层状剪切破碎为主,使得碎屑流在“摊薄效应”下继续运动与纵向扩展,碎屑流运动由“干”的高速流态化转为固态静止的过程极为迅速,从而保留有连续脊丘与线槽等特殊流体性质下的堆积地貌形态。研究认为,地震发生后尼续滑坡源区坡体结构控制了滑坡解体与破坏过程,并按照由前至后的顺序依次下滑运移,受自身势能条件控制,自源区而下的滑体在前缘堆积区产生自左至右依次叠加堆积作用,这是尼续滑坡堆积范围向下游明显偏转的主要原因。
Abstract:Nixu landslide is located in the middle of the Yadong-Gulu Rift Valley in southern Tibet. The accumulation of Nixu landslide is the landform of the flat river valley. It is a typical “flat” rocky long-runout landslide developed in the back-land of the Qinghai–Tibet Plateau. The landslide accumulation area has a complete accumulation structure and typical debris flow patterns. The investigation and research on Nixu landslide will help to reveal the mechanism of movement and accumulation differentiation of this type of “flat” high-speed debris flow. A detailed ground survey of the Nixu landslide and its components in the accumulation area was carried out, combined with geophysical methods to reveal the failure characteristics of the sliding surface at the bottom of the source area as well as the mechanism of the formation of the landslide.The high resolution remote sensing interpretation and particle test were used to reveal the spatial distribution rules of various stacked structures. According to the research of the evolution of the debris flow accumulation structure and spatial morphology of Nixu landslide, it is proposed that the formation and evolution of “flat” high-speed debris flow can be divided into three sections: Structure fragmentation in the slope section of the source area, the material structure debrisification in the sliding zone, and the debris flow fluidization movement and accumulation in the leading edge. The structure of the corresponding sliding mass had the characteristics of step development of fragmentation-debrisification-fluidization. In the sliding zone and leading edge, the high-speed sliding mass movement was affected by the friction of the base, and a horizontal layered shear fracture surface could be generated inside, so that the debris flow continued to move and expand longitudinally under the “dilution effect”. The process of debris flow at the bottom transition from “dry” high-speed fluidization to solid and still was extremely rapid, and thus it maintained the accumulation morphology under the special fluid properties such as continuously distributed ridge and trunking. According to the research, it was proposed that the disintegration and destruction of Nixu landslide after earthquake were controlled by the slope of the source area, and they slided from front to back in sequence, controlled by their own potential energy conditions. The sliding body from the source area was stacked in the front edge accumulation area from left to right. It was the main reason for the deflection of the stacking plane to the downstream.
文章编号:202000238     中图分类号:P694    文献标志码:
基金项目:国家重点研发计划项目(2018YFC1505003);国家自然科学基金项目(41977246)
作者简介:崔杰(1977-),男,讲师,博士.研究方向:边坡稳定性评价.E-mail:cuijie@swust.edu.cn
引用文本:
崔杰,高春玉,张志龙,姚依凡.平敞型高速远程滑坡碎屑流运动与堆积演化规律研究[J].工程科学与技术,2020,52(6):22-29.
CUI Jie,GAO Chunyu,ZHANG Zhilong,YAO Yifan.Debris Flow Movement and Accumulation Evolution of Flat Long-runout Landslide[J].Advanced Engineering Sciences,2020,52(6):22-29.