甘肃省庆阳市环县西部地区黄土滑坡形成条件及机理研究

发布时间：2018-01-06 05:17

本文关键词：甘肃省庆阳市环县西部地区黄土滑坡形成条件及机理研究　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：环县西部地区地质环境脆弱,地质灾害频发,在一定程度上威胁着当地居民人身财产安全,制约区内社会经济的快速发展。但环西部地区蕴藏着丰富的风能资源,目前该区着力开发风电资源,以带动当地的经济发展,风电工程会开挖大量的边坡,使得区内地质灾害将呈现加重趋势,对当地居民生命财产安全和各类基础设施存在更大的潜在威胁。本文以该区黄土滑坡形成机理研究为出发点,以调查的341个不同类型滑坡为研究基础,对区内黄土滑坡类型、规模、发育规律、形成条件进行了分析总结。通过室内分析测试获得研究区内黄土的土力学特征和破坏条件,结合野外调查资料,运用数值模拟方法对黄土滑坡形成机理进行系统研究,主要得出以下结论:在调查过程中发现研究区黄土滑坡影响因素众多,包括构造运动、地形地貌、地层岩性、地震、人类工程活动、降雨、地表水、地下水、沟谷侵蚀、节理裂隙、洞穴、冻土与积雪融化、土壤盐渍化等因素的影响。研究区主要发育了四类滑坡:沟谷滑坡、窑洞滑坡、地震滑坡及公路切坡滑坡。统计结果显示:沟谷滑坡占38.70%,窑洞切坡滑坡占56.89%,地震滑坡占1.07%,公路切坡滑坡占3.34%。坡向上看0~90°占24.04%,90~180°占24.93%,180~270°占36.36%,270~360°占14.66%。在规模上小型滑坡56.59%,中型滑坡占43.41%,无大型及以上滑坡。从厚度上看浅层滑坡95.89%,中层滑坡占4.11%,无厚层及以上滑坡。研究区黄土滑坡分布特征分析得到区内黄土滑坡有明显的时间分布规律、空间分布规律及多期次活动特征。时间分布上集中在4、7两个月发生,空间分布规律有较强的群集性和分异性,群集主要体现在沿沟谷滑坡分带明显,密度大,滑坡群间具有连续性。分异性主要体现在沟谷常发生具有统一滑动面的黄土层内滑坡和黄土层与下伏基岩的切层滑坡。数值模拟计算结果显示窑洞切坡滑坡所产生的变形破坏与含水率、坡高、坡度和窑洞掘进深等因素有密切联系,随着含水率、坡高、坡度和窑洞掘进深的增加,窑洞切坡体所受的应力向窑洞进口顶板部位集中,其范围为窑洞深度的1/3~2/3,并在不同影响因素的作用下,最终产生变形破坏。公路切坡滑坡在含水率、坡高、坡度的影响下,斜坡体的应力向斜坡中上部集中,并且随着含水率、坡高、坡度的增加其范围不断扩展,最终产生滑动。沟谷滑坡在含水率、坡高、坡度的影响下斜坡体的应力主要在坡体中下部集中,且随着含水率、坡高、坡度的增加,其范围变大,应力变大,尤其是在坡脚区。
[Abstract]:The western region of Huanxian County has a fragile geological environment and frequent geological disasters, which to a certain extent threaten the safety of local residents' personal and property. Restrict the rapid development of social economy in this area. However, there are abundant wind energy resources in the western region. At present, the region will focus on the development of wind power resources in order to promote the local economic development, wind power engineering will excavate a large number of slopes. The geological hazards in the area will present an aggravating trend, and there will be a greater potential threat to the safety of local residents' lives and property and various kinds of infrastructure. This paper starts with the study of the formation mechanism of loess landslide in this area. Based on 341 different types of landslides investigated, the types, scale and developmental regularity of loess landslides in this area are studied. The formation conditions were analyzed and summarized. The soil mechanics characteristics and failure conditions of loess in the study area were obtained by indoor analysis and test, and combined with field investigation data. Using numerical simulation method to study the formation mechanism of loess landslide, the main conclusions are as follows: in the process of investigation, it is found that there are many factors affecting loess landslide in the study area, including tectonic movement, topography and geomorphology. Stratigraphic lithology, earthquakes, human engineering activities, rainfall, surface water, groundwater, gully erosion, joint fissures, caves, permafrost and snow melt. There are four types of landslides in the study area: gully landslide, cave landslide, earthquake landslide and highway slope landslide. The statistical results show that Gougu landslide accounts for 38.70%. Cave slope landslide accounts for 56.89, earthquake landslide accounts for 1.07, highway slope slope landslide accounts for 3.34.The slope slope is 0.90 掳, 24.040.90 掳and 24.93% 掳. 180 掳, 270 掳, 36.36 掳, 270 掳, 360 掳, 14.66.The scale of the small landslide is 56.59, and the medium-sized landslide accounts for 43.41%. There is no large landslide and above. From the thickness of shallow landslide 95.8910, middle-level landslide accounted for 4.11%. By analyzing the distribution characteristics of loess landslide in the study area, it is found that the loess landslide has obvious temporal distribution, spatial distribution and multi-period activity characteristics. The time distribution is concentrated in 4. In two months, the spatial distribution law has strong clustering and heterogeneity, and the clustering is mainly reflected in the obvious zoning along the gully landslide and the high density. There is continuity between the landslide groups. The difference is mainly reflected in the occurrence of landslides in the loess layer with uniform sliding surface in the gully and in the shearing layer of the loess layer and the lower bedrock. The numerical simulation results show that the landslide in the cave slope is produced by the landslide. Raw deformation, failure and moisture content. With the increase of water content, slope height, slope depth and cave excavation depth, the stress of the slope body is concentrated on the entrance roof of the cave with the increase of the water content, the slope height, the slope depth and the driving depth of the cave, and other factors are closely related to the slope height, the slope degree and the driving depth of the cave. Its range is 1 / 3 / 2 / 3 of cave depth, and under the action of different influence factors, it will eventually produce deformation and failure. The slope slope landslide is affected by water content, slope height and slope gradient. The stress of slope body is concentrated on the middle and upper part of the slope, and with the increase of water content, slope height and slope gradient, the range of slope is continuously expanded, and finally sliding. The gully landslide in water content, slope height. Under the influence of slope, the stress of the slope is mainly concentrated in the middle and lower part of the slope, and with the increase of water content, slope height and gradient, the range and stress of the slope become larger, especially at the bottom of the slope.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

【相似文献】