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工程科学与技术:2020,52(6):10-21
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青藏高原典型液化型高速远程滑坡形成机制分析
(北京工业大学 建筑工程学院,北京 100124)
Analysis on the Formation Mechanism of Rapid and Long Runout Landslides in Liquefaction-type in Tibetan Plateau
(College of Architecture and Civil Eng., Beijing Univ. of Technol., Beijing 100124, China)
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投稿时间:2020-04-14    修订日期:2020-10-14
中文摘要: 高速远程滑坡作为一种特殊的地质灾害,具有运动速度快、滑动距离远、致灾范围广等特征,一旦发生往往给人类的生命财产带来巨大的损失,因此,针对其超强运动机制的研究一直受到国内外滑坡领域的高度关注。液化减阻作为高速远程滑坡发生超强运动的一个重要机制,强调滑坡运动过程中出现超孔隙水压力累积、有效应力降低等液化行为,导致滑坡基底摩擦系数减小,发生高速远程运动。本文根据前人研究结果对液化的影响因素和高速远程滑坡的液化机制进行总结,将不排水加载作用下滑坡的液化机制归纳为结构液化和滑动带液化两种;并基于详细的现场调查对青藏高原地区两类典型的液化型高速远程滑坡(玉树滑坡和乱石包滑坡)的形成机制进行了初步分析。结果表明:玉树滑坡和乱石包滑坡在启动条件、运动和堆积地貌单元及液化机制等方面均有差异。玉树滑坡为发生于山间沟谷中、由强降雨诱发的崩坡积层滑坡,滑坡体积小但运动距离远,滑带土为堆积于沟谷中的饱和松散砂质黏土(细粒土),可忽略颗粒的剪切破碎性;不排水加载作用破坏了松散的土体结构,从而诱发滑坡液化;乱石包滑坡发生于山前盆地,由古地震触发并斜抛启动,滑带土为风化的花岗岩粗砂,具有剪切易破碎性,土颗粒破碎引起滑动带液化是滑坡发生高速远程运动的主要原因。
Abstract:As a special landslide hazard, rapid and long runout landslides display high mobility, long runout travel distance and wide damage area, and bring great loss to human life and property, of which dynamic mechanisms have attracted demand attentions of the researchers all over the world. Liquefaction mechanism of landslides was proposed to explain that the formation of excess pore water pressure and the reduction of effective stress lead to the decrease of the friction coefficient of the base and the landslide long runout movement. In this paper, we reviewed the factors affecting the liquefaction intensity and the liquefaction mechanism of the landslides on the basis of previous research, and the mechanisms of the liquefied landslides were generally summarized into two types, i.e., structural liquefaction and sliding zone liquefaction. Based on remote sensing interpretation and field investigation, the preliminary research of the formation mechanisms of two typical liquefied rapid-long-runout landslides named Yushu landslide and Luanshibao landslide in Tibetan Plateau were conducted. Results showed that Yushu and Luanshibao landslides were different in triggering mechanism, movement and accumulation geomorphologic unit, and liquefaction mechanism. Yushu landslide was a collapsed deposit landslide occurring in a mountain valley with a small volume but a long runout distance triggered by heavy rainfall. The sliding zone soil was saturated loose sandy clay (fine grain) accumulated in the gully before landsliding, the particle breakage of which during shearing could be negligible. The liquefaction was mainly induced by destroying the soil structure under undrained loading. Luanshibao landslide was a granite landslide occurring in the piedmont basin triggered by oblique-thrusting during an ancient earthquake, the sliding zone soil of which was saturated loose weathered granite sand having crushability. The sliding zone liquefaction induced by grain crushing was the main reason resulting in its rapid and long runout movement.
文章编号:202000282     中图分类号:P642    文献标志码:
基金项目:国家重点研发计划项目(2018YFC1505003)
作者简介:朱雨轩(1992-),男,博士生.研究方向:滑坡机理及动力过程.E-mail:yxzhu2017@163.com
引用文本:
朱雨轩,戴福初,梁莲姬.青藏高原典型液化型高速远程滑坡形成机制分析[J].工程科学与技术,2020,52(6):10-21.
ZHU Yuxuan,DAI Fuchu,LIANG Lianji.Analysis on the Formation Mechanism of Rapid and Long Runout Landslides in Liquefaction-type in Tibetan Plateau[J].Advanced Engineering Sciences,2020,52(6):10-21.