高速铁路土质边坡降雨力学响应及安全性评价研究

发布时间：2018-07-27 20:19

【摘要】：随着近年来我国经济建设的迅速发展,特别是西部大开发战略的实施,在西南山区高速铁路建设中,出现了大量的工程高陡边坡。由于建设规模的不断增大和地形地质条件的限制,工程边坡的高度越来越大、坡度越来越陡。伴随着近年来暴雨洪涝等自然灾害的加剧,工程边坡灾害问题日益突出,使得开展相关的减灾科研工作迫在眉睫。因此,本文结合中国铁路工程总公司(原铁道部)重大科技开发计划《高陡边坡运营安全防灾监控及报警系统技术研究》(2010G018-E-4),针对高速铁路沿线边坡降雨力学响应及安全性评价问题,从非饱和岩土力学、边坡工程学、试验力学、现代试验技术、非线性数学方法等角度着手,开展了土工试验、模型试验、数值仿真、理论分析等研究,为西南山区高速铁路建设提供理论依据和技术支持。(1)以西南山区典型的地质条件为基础,系统地开展了非饱和粉质粘土的矿物成分分析、土壤颗粒组成分析、击实、非饱和土水(SWCC)、直剪、固结等试验,得出了不同孔隙比和级配组成情况下的吸脱湿土水曲线,并基于上述试验结果修正了Feng-Fredlund模型,探讨了孔隙比和基质吸力对于土体抗剪强度的影响,揭示了土体在不同基质吸力状态下的“软化”特征及内在原因。借助于非饱和土固结试验提出了土体非饱和弹性模量的计算方法。通过上述研究为边坡降雨力学响应分析奠定了基础。(2)以经典坡面流理论基础,在坡面产流问题中引入Green-Ampt模型进行改进,得出坡面入渗-产流的基本方程,并与固-液-气三相流固耦合理论相结合,奠定了三维边坡降雨分析中非饱和流固耦合计算的理论基础。(3)开展了不考虑流固耦合、单纯固-液-气流固耦合,以及本文首次提出的综合考虑坡面产流-入渗耦合与固-液-气流固耦合这三种方法的对比研究。研究结果表明：不考虑流固耦合的计算方法在坡体中的浸润线会扩展过快,与实际情况差别较大。在长时间小雨工况下,采用本文方法和单纯的固-液-气三相耦合法的方法所得的浸润线基本吻合,短时间降雨工况下本文方法所得的浸润线介于非流固耦合和固-液-气三相流固耦合法之间,但随着降雨时间的持续,两种计算方法所得的浸润线差别略有减小。深化拓展了非饱和土力学理论在边坡降雨计算中的应用。(4)在分析现有土工离心试验场中降雨及测试系统特点的基础上,结合雾化降雨技术和光纤光栅测试技术,分别研发了新型土工离心边坡降雨试验系统和光纤光栅监测系统及元件。其中新型降雨系统采用涡流雾化技术使得雨雾的均匀性更好,同时解决了以往试验中雨滴过大易造成坡面溅蚀效应过大的现象。新型离心光纤光栅监测系统减弱了传统导线布置对于模型的不利干扰,并解决了测点遇水易失效的难题,从而保证了边坡离心降雨试验中测试数据的有效性和稳定性。为开展边坡降雨试验提供了新的试验手段和研究途径。(5)根据相似原理进行了边坡离心降雨试验相似参数的推导,开展了相关材料的比选和测试,形成了边坡离心降雨试验集选材及筑模、监测元件选型及布设、试验加载及监测的一套综合试验流程,为今后边坡降雨离心试验提供了值得借鉴的技术。(6)结合研发的新型离心降雨试验系统和监测系统,开展了10组不同条件下的工程土质边坡离心降雨模型试验,主要考虑不同的降雨条件、支挡形式、坡度情况、地层变化等,得出了试验过程中坡体位移、含水率、孔隙水压力、支挡结构受力等因子随时间的演化特征及典型的坡体破坏模式等。研究表明：在相同累积降雨量条件下,长时间工况时边坡的滑面位置比短时间暴雨工况时深2-6m；相对于普通边坡,含软弱夹层边坡在降雨中易呈现多层滑动面；边坡预警工作研究应从失稳机理着手,在分析位移因子演化特征规律的基础上,还应综合考虑应力因子变化对边坡稳定的影响。上述研究成果为边坡预警预报研究提供了新的思路。(7)以前述非饱和流固耦合综合分析方法为基础,基于Fortran语言和大型有限元程序Abaqus进行了二次开发,得出了相应的计算模块,在此基础上结合前文中模型试验部分进行了数值仿真研究,得出了降雨过程中典型时刻的有效应力场、基质吸力场、位移场、支护结构受力等的分布模式和变化特征,补充了模型试验对物理场研究的不足。并进一步研究了降雨形式、坡度条件和地层状况对于边坡降雨稳定系数的影响,得出了西南山区土质边坡需要开展降雨安全警戒的坡度、坡高和软弱夹层特征。深化了对于西南山区铁路沿线边坡降雨安全性影响因素的认识。(8)基于粗糙集-支持向量机方法,结合贵广、兰渝、成绵乐高速铁路沿线30多个土质边坡工点的资料调研,建立了西南山区铁路沿线土质边坡安全性评价数据库和评价模型,提出了从宏观角度判断边坡降雨安全性的方法。
[Abstract]:With the rapid development of China's economic construction in recent years, especially in the implementation of the western development strategy, there have been a large number of high and steep slopes in the construction of high speed railway in the southwest mountain area. Due to the increasing scale of construction and the limitation of terrain and geological conditions, the height of the slope is increasing and the slope is getting steeper and steeper. Because of the intensification of natural disasters such as rainstorm, flood and flood, the problem of engineering slope disaster is becoming more and more serious, which makes it urgent to carry out the related research work on disaster reduction. Therefore, this paper combines the major scientific and technological development plan of the China Railway Engineering General Corporation (the Ministry of Railways) "2010G018-E-4" for high and steep slope operation safety prevention and control and alarm system. The problem of rainfall mechanics response and safety evaluation of slope along the speed railway is carried out from the angle of unsaturated rock soil mechanics, slope engineering, experimental mechanics, modern test technology, nonlinear mathematical method and so on. The soil test, model test, numerical simulation and theoretical analysis are carried out to provide the theoretical basis for the construction of high speed railway in the southwest mountain area. (1) based on the typical geological conditions in the southwest mountain area, the mineral composition analysis of unsaturated silty clay, soil particle composition analysis, compaction, unsaturated soil water (SWCC), direct shear, consolidation and other tests were carried out, and the moisture absorption and dehumidification soil water curves under the conditions of different pore ratio and gradation were obtained, based on the above test knot. The effect of pore ratio and matrix suction on the shear strength of soil was investigated. The "softening" characteristics and internal causes of soil under different matrix suction conditions were revealed. The calculation method of unsaturated elastic modulus of soil was proposed with the aid of unsaturated soil consolidation test. Through the above study, the slope rainfall was carried out. The basis of the mechanical response analysis is laid. (2) based on the classical slope flow theory, the Green-Ampt model is introduced into the slope runoff generation problem, and the basic equations of the slope infiltration and flow production are obtained, and the theoretical foundation of the unsaturated flow and solid coupling calculation in the three dimensional slope rain analysis is laid by combining with the solid liquid gas three-phase fluid solid coupling theory. 3) the comparative study of the three methods, which are not considering fluid solid coupling, simple solid liquid air solid coupling, and the first proposed method, which is first proposed in this paper to consider the coupling of flow and infiltration and solid liquid airflow solid coupling on slope surface, is studied in this paper. The results show that the infiltration line in the slope body will expand too fast without considering the fluid solid coupling, and it is poor with the actual situation. The infiltration line obtained by this method and simple solid liquid gas three-phase coupling method is basically consistent under the long time rain condition. The infiltration line obtained by this method is between the non fluid solid coupling and the solid liquid gas three-phase fluid solid coupling method under the short time rainfall condition, but with the continuous rainfall time, two kinds of calculating parties are used. The difference in infiltration line obtained by the method is slightly reduced. The application of unsaturated soil mechanics theory to the calculation of slope rainfall is deepened. (4) on the basis of analyzing the characteristics of rainfall and testing system in the existing geotechnical centrifuge test field, a new soil centrifugal slope rainfall experiment is developed in combination with the technology of atomization rainfall and fiber Bragg grating test. The system and fiber Bragg grating monitoring system and components. The new rainfall system uses the eddy current atomization technology to make the evenness of the rain fog better. At the same time, it solves the phenomenon that the raindrop is too large and can easily cause excessive splash erosion in the previous experiments. The new centrifugal fiber Bragg grating monitoring system reduces the adverse interference of the traditional wire arrangement to the model. It also solves the problem that the test point is easy to fail when encountering water, thus ensuring the validity and stability of the test data in the slope centrifuge rain test. It provides a new test means and research approach for the experiment of slope rainfall test. (5) according to the similarity principle, the similar parameters of the slope centrifuge rain test are derived, and the relative selection of the related materials is carried out. And testing, a set of comprehensive test flow of selection and layout of monitoring elements, test loading and monitoring is formed for centrifugal rainfall test set of slope. (6) the new centrifugal rainfall test system and monitoring system have been carried out in 10 different conditions. Engineering soil slope centrifuge rainfall model test, mainly considering different rainfall conditions, support form, slope condition, formation change and so on. The evolution characteristics of slope body displacement, water content, pore water pressure, retaining structure stress and other factors with time are obtained, and the research shows that the same accumulation is in the same accumulation. Under the condition of rainfall, the sliding surface position of the slope is more than 2-6m in the short time heavy rain condition. Relative to the ordinary slope, the slope of the weak interlayer is prone to multilayered sliding surface, and the study of slope early warning should begin with the mechanism of instability. On the basis of the analysis of the evolution characteristics of the displacement factor, the slope should be considered in a comprehensive way. The effect of force factor changes on slope stability. The above research results provide new ideas for slope early warning and prediction research. (7) based on the comprehensive analysis method of unsaturated flow and solid coupling, based on the Fortran language and the large finite element program Abaqus, the corresponding calculation module is obtained. On this basis, the previous article is combined with the previous article. In the medium model test part, the numerical simulation is carried out, and the distribution patterns and changes of the effective stress field, the matrix suction field, the displacement field and the supporting structure are obtained, which supplement the shortage of the model test on the physical field, and further study the rainfall form, the slope condition and the formation condition. The influence of slope rainfall stability coefficient has been concluded that the slope, slope height and soft intercalation characteristics of the southwest mountainous soil slope need to carry out the slope, slope height and weak interlayer. (8) based on the rough set support direction quantity machine method, combined with GUI Guang, Lanzhou, chengmianle high speed railway The data investigation of more than 30 soil slope work points along the railway line has been made to establish the database and evaluation model of the safety evaluation of the soil slope along the railway in the southwest mountain area, and the method of judging the safety of the slope from the macroscopic angle is put forward.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU43

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