持续强降雨条件下超高填方体边坡稳定性研究

发布时间：2018-01-24 02:30

本文关键词： 超高填方边坡持续强降雨稳定性　出处：《重庆大学》2014年硕士论文　论文类型：学位论文

【摘要】：在典型山区河谷地带等地形复杂地区开展城镇基础设施建设通常相当困难，具有可用地资源极为紧缺与缺少适合大规模工程建设的自然“开阔平地”的突出矛盾，这意味着在这类山地城市建设中进行开山填沟造地的人工高填方工程将成为解决建设用地的重要途径之一，超高填方体的稳定性便成了影响工程安全稳定运营的关键。在影响超高填方体稳定性的众多因素中，降水入渗是诱发填方边坡失稳破坏的主要因素，尤其是持续强降雨对边坡的稳定性的威胁更不容忽视，研究降雨入渗对超高填方边坡稳定性的影响机理和变形破坏过程对于填方体排水设计、施工等具有重要的参考价值。鉴于此，本文以重庆市某机场扩建工程的超高填方体为依托，开展持续降雨对超高填方体边坡稳定性影响的研究。本文通过收集资料、野外地质调查等手段，查明场区的工程地质及水文地质环境条件，掌握了基岩边坡的结构类型以及填方体堆载变形破坏模式；通过施工前现场调研，从总体上掌握场区地形、地质及基岩边坡稳定性状况；在对场区地质条件、施工设计方案、现场试验、高填方变形、沉降监测及相关检测成果分析的基础上，结合工程地质和数值反馈仿真研究，明确施工区高填方体的稳定性状况，并为其施工设计方案提供参考；通过场地水文地质调研和现场地下水及孔隙水压力监测分析，结合现场渗透试验研究，阐明降雨入渗对超高填方体坡体稳定性的影响，，为机场施工过程中高填方出现的稳定性及加固设计提供参考。本文主要研究工作和成果如下： ①运用极限平衡原理，采用岩土计算软件Geostudio中的稳定性计算模块，计算在不同施工过程超高填方体边坡的稳定性系数。 ②运用有限差分法，采用FLAC3D计算软件讨论了复杂山体模型的建立过程和方法。 ③对高填方边坡变形和稳定性进行更加全面深入的分析，从机理、内部成因等阐述了导致此类变形破坏现象的原因。 ④通过FLAC3D数值模拟对超高填方边坡稳定性分析可知：在复杂地基基岩条件下，原地基形态、地基刚度及其填方体高度对高填方体边坡的变形存在一定的影响，其变形模式主要以竖向变形为主，并伴随一定量向坡外的位移。 ⑤在研究区内选取典型剖面模拟持续降雨条件下的超高填方边坡稳定性，得出其边坡稳定性系数随降雨持时的变化曲线，并得出在持续降雨24～36h是对边坡稳定性影响最大的时间段，并据此采取相关措施保证边坡的稳定性。 ⑥在研究区内选取典型剖面研究具体施工过程中的边坡稳定性，从沉降等值线图中可以发现最大沉降并不是发生在填筑最上层，而是发生在填筑体中间层，从剪应变增量等值线图中可以发现剪应变增量最大的位置大都集中在基岩与填方体交界处，因此基岩的基覆界面是不易忽视的滑坡位置。
[Abstract]:It is usually very difficult to develop urban infrastructure in typical mountainous and valley areas with complex topography. There is a serious contradiction between the shortage of available land resources and the lack of natural "open flat land" suitable for large-scale engineering construction. This means that in the construction of this kind of mountain cities, the artificial high fill project will become one of the important ways to solve the problem of construction land. The stability of super-high embankment has become the key to the safe and stable operation of the project. Among the many factors affecting the stability of the super-high embankment, precipitation infiltration is the main factor that induces the unstable failure of the fill slope. Especially the threat to slope stability caused by continuous heavy rainfall can not be ignored. The influence mechanism of rainfall infiltration on the stability of super-high fill slope and the process of deformation and failure for the drainage design of fill body are studied. In view of this, the influence of continuous rainfall on the slope stability of a certain airport extension project in Chongqing is studied in this paper. In this paper, by means of collecting data and field geological survey, the engineering geology and hydrogeological environment conditions in the field area are found out, and the structural types of bedrock slope and the failure mode of the filling body heaped deformation are mastered. Through the field investigation before construction, we can master the terrain, geology and stability of bedrock slope in general. Based on the analysis of geological conditions, construction design scheme, field test, high fill deformation, settlement monitoring and related detection results, combined with engineering geology and numerical feedback simulation research. The stability of the high fill in the construction area is clarified, and the reference is provided for the construction design. Through site hydrogeological investigation and field monitoring and analysis of groundwater and pore water pressure, combined with field permeation test, the influence of rainfall infiltration on slope stability of ultra-high fill is clarified. This paper provides a reference for the stability and reinforcement design of high fill during airport construction. The main research work and results are as follows: 1 using the limit equilibrium principle and the stability calculation module in Geostudio software, the stability coefficient of super-high fill slope in different construction process is calculated. 2 the process and method of building complex mountain model are discussed by using finite difference method and FLAC3D software. (3) the deformation and stability of high fill slope are analyzed comprehensively and deeply, and the causes of such deformation and failure are explained from the mechanism and internal cause of formation. (4) through the FLAC3D numerical simulation, the stability analysis of the super-high fill slope shows that under the condition of complex foundation rock, the original foundation form. The stiffness of the foundation and the height of the fill have a certain influence on the deformation of the high fill slope. The deformation mode is mainly vertical deformation and accompanied by a certain amount of displacement outside the slope. 5. Select typical sections to simulate the stability of super-high fill slope under the condition of continuous rainfall in the study area, and obtain the curve of slope stability coefficient with rainfall duration. It is concluded that the maximum influence on slope stability is in 24 ~ 36 h of continuous rainfall, and the relevant measures are taken to ensure the stability of the slope. 6 select typical sections in the study area to study the slope stability in the concrete construction process. From the settlement isoline map, we can find that the maximum settlement does not occur in the top layer of the filling, but in the middle layer of the filling body. From the isoline diagram of shear strain increment, it can be found that the position of maximum shear strain increment is mostly concentrated at the junction of bedrock and fill body, so the base interface of bedrock is not easy to ignore.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU43

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