泾阳南塬多序次黄土滑坡运动机理研究

发布时间：2018-05-27 01:30

本文选题：运动机理 + 多序次黄土滑坡　；参考：《西安科技大学》2017年硕士论文

【摘要】：多序次黄土滑坡是黄土滑坡的一种特殊类型,表现为同一塬段斜坡发生多起滑动,滑坡体现了一定的复发性,在时空上体现了多序次的特点。多序次黄土滑坡的发生使得塬边不断缩减,既威胁了塬面上的居民生产生活,也造成了塬下土地资源的损失和基础设施的损坏。本文选取泾阳南塬多序次黄土滑坡作为典型代表,在系统归纳多序次黄土滑坡的研究现状和研究成果的基础上,分析了研究区内地质环境背景及泾阳南塬多序次黄土滑坡的运动特征及滑坡特征参数,并运用PFC颗粒离散元数值模拟软件模拟了泾阳南塬多序次黄土滑坡的三个序次的滑动过程,探讨了泾阳南塬多序次黄土滑坡的运动机理,研究成果对于多序次黄土滑坡的机理分析及防治具有一定的指导意义。本文主要研究内容及结论如下:(1)通过野外现场调查,结合遥感解译资料:研究区内有14处斜坡发生过多序次的破坏,形成了 38起以上的滑动,其中有14处发生过2起以上的滑动,6处3起以上的滑动,2处发生4起滑动。根据滑坡发生的力学机制可以将泾阳南塬黄土滑坡分为黄土流滑和黄土滑动两类。按照滑坡发育的先后顺序可将研究区多序次黄土滑坡划分为三类:流滑-滑动-滑动型、流滑-流滑-滑动型和滑动-流滑型。(2)利用统计分析的方法,对泾阳南塬黄土滑坡特征参数进行了分析,结果表明:随着滑动序次的递增,滑动体积逐渐递减,剪出口位置也会逐渐升高,滑坡的滑距显著缩短,后序次滑动破坏位置多发生在第一期滑动的后缘位置中部及后缘两侧的斜坡位置。(3)利用PFC颗粒流软件模拟泾阳南塬多序次黄土滑坡运动过程结果表明:泾阳南塬黄土滑坡发生第一起滑动时,多具有高速远程的特征,在高速滑体的前端存在强烈的冲击作用,滑体前端物质与阶地地层物质碰撞会激起涌浪般的尘浪,这些现象都是由于“铲”作用引起的,高速运动的滑体向前端推挤阶地地层,刮蚀阶地物质并裹挟其共同向前运动。区内的黄土滑坡在滑动过程中存在一定的液化效应,高速运动滑体的冲击作用下,滑动面附近土体充分液化,摩擦系数降低,阻力减小甚至全部丧失。刮铲效应和液化效应都具有增大堆积体最大运移距离的作用。(4)研究得出泾阳南塬多序次黄土滑坡的运动机理主要为:灌溉诱滑、堵水促滑、刮铲促滑及滑床触变液化促滑。滑坡发生滑动时滑体重力势能较多地转化为动能,使得滑体以很大的速度冲向阶地层,运动过程中由于刮铲效应和液化效应,堆积体的运移具有远程的特点。
[Abstract]:Multi-order loess landslide is a special type of loess landslide, which is characterized by multiple slippage on the slope of the same plateau, which reflects the recurrence of the landslide and the characteristics of multi-order in time and space. The occurrence of multiple sequential loess landslides makes the edge of the plateau shrink, which not only threatens the production and life of residents on the plateau, but also results in the loss of land resources and the damage of infrastructure under the plateau. In this paper, we select the multi-order loess landslide as the typical representative, on the basis of systematically summing up the present research situation and the research results of the multi-order sub-loess landslide. The background of geological environment in the study area and the movement characteristics and landslide characteristic parameters of multi-sequence loess landslide in the south plateau of Jingyang are analyzed. Using the PFC particle discrete element numerical simulation software, the sliding process of the multi-order loess landslide in Jingyang Nanyuan is simulated, and the motion mechanism of the multi-sequence loess landslide in the south plateau of Jingyang is discussed. The research results have certain guiding significance for the mechanism analysis and prevention of multiple sequence loess landslide. The main contents and conclusions of this paper are as follows: (1) based on field investigation and remote sensing interpretation data, there are 14 slopes in the study area which have been destroyed in many order, resulting in more than 38 slips. Among them, there were more than 2 slips in 14 places, 6 slips in 6, 3 slippages in 3 and 4 slippages in 2 places. According to the mechanical mechanism of landslide occurrence, loess landslide can be divided into loess flow slip and loess slide. According to the sequence of landslide development, the multi-sequence subloess landslide in the study area can be divided into three categories: fluid-slip type, fluid-slip type and glide-flow slip type. The characteristic parameters of loess landslide in the south plateau of Jingyang are analyzed. The results show that with the increase of sliding order, the sliding volume decreases gradually, the shear exit position increases gradually, and the slip distance of the landslide is shortened significantly. The post-sequence subslip failure location mostly occurred in the slope position of the middle part of the first stage slip and the two sides of the rear edge.) the simulation of the motion process of the multi-sequence sub-loess landslide in Jingyang South tableland by PFC particle flow software shows that: Jingyang South tableland is the south plateau of Jingyang. When the first slide occurred in the loess landslide, Most of them have the characteristics of high speed and long distance. There is a strong impact on the front end of the high speed slippery body. The collision between the front part of the slide body and the terrace material will arouse the billowing wave. These phenomena are all caused by the "shovel" action. The sliding body with high speed pushes the terrace to the front and erodes the terrace material and carries it forward together. There is a liquefaction effect in the sliding process of loess landslide in the region. Under the impact of high speed moving sliding body, the soil near the sliding surface is fully liquefied, the friction coefficient is reduced, and the resistance is reduced or even lost. The research shows that the motion mechanism of multi-sequence loess landslide in south plateau of Jingyang is mainly as follows: irrigation induced slip, water plugging promoting slide, scraping shovel promoting slide and sliding by tactile liquefaction of sliding bed. When the landslide occurs, the gravity potential energy of the sliding body is mostly converted into kinetic energy, which causes the sliding body to rush to the strata at a high speed. During the process of movement, the migration of the accumulated body has the characteristics of remote because of the effect of scraping and liquefaction.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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