工程堆载触发黄土滑坡研究

发布时间：2018-01-30 03:40

本文关键词： 工程堆载黄土滑坡模型试验成因机理变形分区　出处：《长安大学》2015年博士论文　论文类型：学位论文

【摘要】：在我国,黄土分布面积为63万km2,约占陆地面积的6.6%,黄土高原地区黄土分布广泛、地层完整、沉积厚度大,使之成为黄土天然博物馆,也是世界黄土研究的前沿高地。党的十八大提出的城镇化建设目标,在黄土高原地区,黄土重大灾害严重制约城镇化建设,很难在该地区实现目标任务。如兰州市,黄土滑坡、崩塌、泥流等重大黄土地质灾害几乎包围了这座城市,人们生命财产安全受到严重威胁,黄土重大灾害严重制约了兰州城市的发展;陕北革命圣地延安市,市区主要集中狭长的斜坡地带,共发育有大型黄土滑坡、崩塌近80处,黄土重大灾害严重制约了延安城市的发展。兰州市和延安市都被迫在郊县削山填沟,兴建新城,填土场地修建新城区很难回避由工程堆载触发的黄土滑坡灾害问题。本论文以工程堆载触发黄土滑坡的孕育、成灾及演化机理为研究主线,对其分布规律、孕灾模式、成因机理、演化过程等理论和技术方法进行较为深入系统研究,主要结论如下:(1)触发黄土滑坡的主要堆载类型:面状堆载、点状堆载,其中面状堆载又可分为条形均布荷载、矩形均布荷载和方形均布荷载以及三角形面状荷载;(2)堆载对坡体竖向应力的影响深度较大,对水平应力的影响深度约为荷载区宽度的2倍,堆载引起的最大剪应力出现在荷载区边缘,这也是荷载区边缘出现剪切裂缝的主要原因;(3)堆载触发黄土滑坡一般发育两条滑带,加载区外侧拉张裂缝区裂缝向下延展与剪切裂缝联通形成浅层滑带,一般在坡体的中部剪出,加载区内侧拉张裂缝区裂缝向下延展与剪切裂缝联通形成的深层滑带,一般在坡脚附近剪出;(4)结合物理模型试验、离心模型试验、数值模拟计算及边坡土体附加应力综合分析,边坡体的塑性区首先出现在张拉破坏区下部和坡脚,并向坡体中间延展,堆载触发黄土滑坡变形分区既滑动区、变形影响区和非影响区;(5)工程堆载触发边坡变形破坏可分为三种模式:触发老滑坡复活、触发饱水层蠕滑变形、触发填土区边坡变形破坏;堆载触发黄土滑坡滑带的形态及形成过程与荷载值、荷载部位及边坡坡度有关。
[Abstract]:In China, the loess distribution area is 630,000 km ~ 2, accounting for about 6.6% of the land area. Loess in the Loess Plateau region is widely distributed, stratigraphic integrity, deposition thickness is large, making it a loess natural museum. It is also the advanced highland of loess research in the world. The goal of urbanization is put forward by the 18 Party Congress. In the Loess Plateau region, the major disasters of loess seriously restrict the urbanization construction. It is difficult to achieve the target tasks in this area. For example, Lanzhou City, loess landslide, collapse, mudflow and other major loess geological disasters almost surrounded the city, people's lives and property safety is seriously threatened. The development of Lanzhou city is seriously restricted by the major disasters in loess. The city of Yan'an, a revolutionary shrine in northern Shaanxi, is mainly concentrated on narrow sloping areas. There are large loess landslides and nearly 80 landslips in the urban area. The development of Yanan city is seriously restricted by the major disasters in loess. Both Lanzhou and Yan'an are forced to cut mountains and fill ditches in suburban counties to build new cities. It is difficult to avoid the loess landslide disaster caused by engineering heaps in the construction of new urban areas. In this paper, the mechanism of engineering heaps triggering loess landslides is taken as the main line of study, and its distribution law is discussed. The main conclusions are as follows: 1) the main types of heaps triggered by loess landslides: surface heaps, dotted heaps. The surface load can be divided into strip uniform load, rectangular uniform load, square uniform load and triangular plane load. (2) the depth of influence of surcharge on vertical stress of slope body is great, and the depth of influence on horizontal stress is about 2 times of the width of load zone, and the maximum shear stress caused by surcharge appears at the edge of load zone. This is also the main reason for the shear cracks in the edge of the load zone. Generally, two slip zones are developed in the Loess landslide triggered by heap-load. The cracks in the lateral tension fracture zone extend downward and the shear cracks connect to form a shallow slip zone, which is generally cut out in the middle of the slope body. The deep slip zone formed by the downward extension of the cracks in the inner tension fracture zone of the loading area and the connection of the shear cracks are generally cut out near the foot of the slope. Combined with physical model test, centrifugal model test, numerical simulation and comprehensive analysis of additional stress of slope soil, the plastic zone of slope body first appears in the lower part of tensile failure zone and slope foot. And it extends to the middle of the slope, and the load triggers the loess landslide deformation zone, which includes the sliding zone, the deformation affected area and the non-influence area. 5) the deformation and failure of the slope triggered by heaps can be divided into three types: triggering the revival of the old landslide, triggering the creep deformation of the saturated layer and triggering the deformation and failure of the slope in the fill area; The shape and forming process of the loess landslide slide triggered by the surcharge are related to the load value, load position and slope gradient.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P642.22

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