白塔山黄土滑坡破坏机理及整治措施研究

发布时间：2018-07-03 05:03

本文选题：白塔山 + 黄土　；参考：《兰州交通大学》2017年硕士论文

【摘要】：本文以兰州市白塔山黄土边坡滑坡病害为工程背景,对黄土地区滑坡的破坏机理及整治技术进行研究。通过查阅相关文献资料,首先,对黄土的分布、特性以及滑坡的成因、分类进行了总结分析;其次,结合国内外滑坡研究现状对黄土地区滑坡的触发因素、变形特征等进行了总结;最后,通过一些基本的物理性质试验、三轴剪切试验、室内模型试验、数值模拟以及相关的一些数据资料分析,对白塔山碑林地区黄土滑坡的发生机理及整治措施做了较为详细的研究。得出的主要结论如下:(1)影响黄土边坡稳定性的因素除了地形地貌、地质条件外还有降雨入渗、地震、冻融、人类活动等外界因素。对于黄土滑坡的防治要结合当地条件,综合考虑内外因素,消除水的影响,采取较为合理的支护方案。(2)依据现场取回的土样,在室内用原状土做了密度试验和含水率试验,用扰动土做了击实试验,用重塑土做了三轴剪切试验。结果表明,取回土样的平均密度为1.47g/cm3,平均含水率为3.9%,最大干密度为1.83 g/cm3,最优含水率为16.4%,土样的粘聚力和内摩擦角随着含水率的变化而相应地改变。(3)在室内降雨模型试验中,从降雨开始到结束,雨水的入渗率逐渐减小并趋于稳定,入渗率降低是土体从非饱和到吸水饱和,渗透性降低,基质吸力减小的结果。在降雨过程中,坡体总的入渗规律为:坡体顶部比斜坡部分入渗速率快,坡体表面含水率持续增加接近饱和,随后逐渐入渗到坡体内部。对沿着斜坡浅层部分的三个点进行孔隙水压力监测时,孔隙水压力先增长到峰值,然后在某一范围内上下浮动,降雨分别进行到150分钟和350分钟的时候,坡体中部的浅层位置处孔隙水压力明显减小,该处土体出现一定程度的失稳破坏。从降雨开始到发生大规模滑坡结束,整个过程共分为三个阶段,即裂缝的产生、滑体的形成和滑体的蠕动破坏。(4)用极限平衡法对H-1号前级斜坡进行稳定性分析表明,斜坡在自然状态下的稳定系数为1.028,是欠稳定的;在长期降雨及灌溉入渗下的稳定系数为0.937,是不稳定的。用FLAC 3D数值模拟发现,斜坡在自然状态下用抗滑桩支护前后的稳定系数分别为1.04、1.52;在长期降雨及灌溉入渗下用抗滑桩支护前后的稳定系数分别为0.95、1.37。
[Abstract]:In this paper, based on the engineering background of the landslide disease of the Baita Mountain Slope in Lanzhou, the failure mechanism and regulation technology of the landslides in the loess area are studied. First, the distribution, characteristics and causes of the landslides are summarized and analyzed. Secondly, the loess area is combined with the status of landslides at home and abroad to the loess region. The triggering factors and deformation characteristics of the landslide are summarized. Finally, through some basic physical properties test, three axis shear test, indoor model test, numerical simulation and some related data analysis, the mechanism and regulation measures of loess landslides in the Beit mountain forest area are studied in detail. The conclusions are as follows: (1) the factors affecting the stability of loess slope are in addition to topography and geomorphology, and outside factors such as rainfall infiltration, earthquake, freezing thawing, human activity and other factors. The prevention and control of loess landslides should be combined with the local conditions, comprehensive consideration of internal and external factors to eliminate the impact of water, and take a more reasonable support scheme. (2) retrieved according to the site. The soil sample was tested in the density test and water content test in the original soil. The three axis shear test was made with the remolded soil. The results showed that the average density of the remolded soil was 1.47g/cm3, the average water content was 3.9%, the maximum dry density was 1.83 g/cm3, the optimum water content was 16.4%, the cohesive force and the internal friction angle of the soil samples were along with the internal friction angle. (3) in the indoor rainfall model test, from the beginning to the end of the rainfall, the infiltration rate of the rain gradually decreases and tends to be stable, the infiltration rate is reduced from unsaturated to water saturation, the permeability is reduced, and the matrix suction is reduced. In the process of rainfall, the infiltration law of the slope body is the top of the slope body. The infiltration rate of the part is faster than the slope part, and the water content of the surface of the slope continues to increase close to saturation, and then gradually infiltrate into the interior of the slope. When the pore water pressure is monitored at three points along the shallow part of the slope, the pore water pressure increases first to the peak, and then fluctuate up and down in a certain range, and the rainfall is carried out to 150 and 350 minutes respectively. At the same time, the pore water pressure in the shallow layer of the middle part of the slope is obviously reduced, and the soil body appears to a certain degree of instability and failure. From the beginning of the rain to the end of the large-scale landslide, the whole process is divided into three stages, namely, the formation of the cracks, the formation of the slide body and the creep damage of the slide body. (4) the slope of the H-1 front grade is entered by the limit equilibrium method. The stability analysis of the slope shows that the stability coefficient of the slope is 1.028 under the natural state, and it is less stable. The stability coefficient of the long-term rainfall and irrigation infiltration is 0.937, which is unstable. The stability coefficient of the slope under the natural state of the slope under the natural state of the anti slide pile is 1.04,1.52, respectively, and in the long-term rainfall and irrigation, the stability coefficient of the slope is 1.028 under the natural state. The stability coefficient before and after the use of anti slide piles is 0.95,1.37.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43;TU753

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