受地下水影响的膨胀土渠道边坡破坏机理及支护技术研究
发布时间：2018-10-26 08:21
【摘要】：膨胀土是一种亲水性强,遇水膨胀的土体,易造成工程破坏,是地质灾害发生主要诱因之一,同时也是一项全球性的治理难题。南水北调是国家解决北方缺水的重要战略工程,南水北调中线全程长1277公里,但其在南阳、沙河等地区共穿越了387公里的膨胀土地带,对其渠道边坡产生了不同程度的破坏,因而解决南水北调膨胀土渠道边坡问题成为该工程的重中之重。国内许多专家学者对南北北调膨胀土已展开了很多研究,但其都是对于膨胀土的开裂特性,降雨入渗,及内部软化结构面等多方面进行探讨,而鲜有考虑到地下水对于南水北调渠道边坡的影响。本文经过对南水北调中线的勘查,总结了渠道边坡的破坏形式,通过试验得出膨胀土的物质组成、化学成分及基本物理性质,分析其膨胀土地质特征。通过对南水北调边坡的破坏形式和开挖渠坡的胀缩结构面研究,把南水北调渠坡的破坏模式总结归纳为3大类,用以认识膨胀土破坏类型与指导膨胀土渠道边坡的加固方案。对南水北调中线膨胀土进行现场取样,进行了大量室内试验,重点研究了其胀缩性能、受干湿循环影响的抗剪强度变化、渗透系数和土水特征曲线。根据试验段实际工况建立数值模型,通过数值模拟和现场监测数据分析渠道边坡的显著影响区深度,分析其渠道边坡内的渗流场分布情况,并耦合边坡稳定性对其安全系数进行验算,得出其渠道边坡破坏机理。从而针对其破坏机理,提出了一套适用一级渠坡以上的内外结合排水+土工格栅加筋体+坡面三维植草的综合防护措施,分析了加固机理措施。本文总结了南水北调渠道边坡的破坏模式,分析确定了大气干湿循环影响区深度,从上层滞水和大气相互作用影响等方面,分析其渗流场分布情况,并分析其安全稳定性,揭示膨胀土渠道边坡的破坏机理,并针对的提出一种综合防护方案,希对南水北调工程膨胀土的研究与防护治理有指导作用。
[Abstract]:Expansive soil is a kind of hydrophilic swelling soil which is easy to cause engineering damage and is one of the main causes of geological disasters and also a global problem of governance. The South-to-North Water transfer Project is an important strategic project for the country to solve the water shortage in the north. The middle line of the South-to-North Water transfer Project is 1277 kilometers long, but it has passed through 387km of expansive land zones in Nanyang, Shahe and other areas, which has caused damage to its canal slope to varying degrees. Therefore, it becomes the most important project to solve the problem of channel slope of the expansive soil in the south-to-north water transfer project. Many domestic experts and scholars have carried out a lot of research on the expansive soil transferred from north to south, but its cracking characteristics, rainfall infiltration, and internal softening structure surface have been discussed in many aspects, such as the cracking characteristics of the expansive soil, the infiltration of rainfall, and the internal softening structure surface, etc. However, the influence of groundwater on the channel slope of the South-to-North Water diversion Project is rarely considered. Based on the survey of the middle route of South-to-North Water transfer Project, the failure form of channel slope is summarized. The material composition, chemical composition and basic physical properties of expansive soil are obtained by experiments, and the characteristics of expansive soil are analyzed. Through the study on the failure form of the slope of the South-to-North Water transfer Project and the expansion and shrinkage structure surface of the excavated canal slope, the failure modes of the channel slope of the South-to-North Water transfer Project are summarized into three categories, which can be used to understand the failure type of expansive soil and to guide the reinforcement scheme of the expansive soil canal slope. Field sampling of expansive soil in the middle line of South-to-North Water transfer Project was carried out, and a large number of laboratory tests were carried out. The expansion and shrinkage properties, shear strength change affected by dry-wet cycle, permeability coefficient and soil-water characteristic curve were studied. According to the actual working conditions of the test section, the numerical model is established, and the distribution of seepage field in the channel slope is analyzed by numerical simulation and field monitoring data to analyze the depth of the significant influence area of the channel slope. The failure mechanism of channel slope is obtained by checking and calculating the safety factor of the coupled slope. In view of its failure mechanism, a set of comprehensive protection measures for three dimensional grass planting on the slope surface of the inner and outer combined drainage geogrid are put forward, and the reinforcement mechanism measures are analyzed. In this paper, the failure mode of channel slope of South-to-North Water transfer Project is summarized, and the depth of dry and wet circulation in the atmosphere is determined. The distribution of seepage field and its safety and stability are analyzed in terms of the interaction between the upper layer of stagnant water and the atmosphere. The failure mechanism of expansive soil channel slope is revealed, and a comprehensive protection scheme is proposed, which is expected to guide the research and protection of expansive soil in South-to-North Water transfer Project.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV672;TV223
，
本文编号：2295133
[Abstract]:Expansive soil is a kind of hydrophilic swelling soil which is easy to cause engineering damage and is one of the main causes of geological disasters and also a global problem of governance. The South-to-North Water transfer Project is an important strategic project for the country to solve the water shortage in the north. The middle line of the South-to-North Water transfer Project is 1277 kilometers long, but it has passed through 387km of expansive land zones in Nanyang, Shahe and other areas, which has caused damage to its canal slope to varying degrees. Therefore, it becomes the most important project to solve the problem of channel slope of the expansive soil in the south-to-north water transfer project. Many domestic experts and scholars have carried out a lot of research on the expansive soil transferred from north to south, but its cracking characteristics, rainfall infiltration, and internal softening structure surface have been discussed in many aspects, such as the cracking characteristics of the expansive soil, the infiltration of rainfall, and the internal softening structure surface, etc. However, the influence of groundwater on the channel slope of the South-to-North Water diversion Project is rarely considered. Based on the survey of the middle route of South-to-North Water transfer Project, the failure form of channel slope is summarized. The material composition, chemical composition and basic physical properties of expansive soil are obtained by experiments, and the characteristics of expansive soil are analyzed. Through the study on the failure form of the slope of the South-to-North Water transfer Project and the expansion and shrinkage structure surface of the excavated canal slope, the failure modes of the channel slope of the South-to-North Water transfer Project are summarized into three categories, which can be used to understand the failure type of expansive soil and to guide the reinforcement scheme of the expansive soil canal slope. Field sampling of expansive soil in the middle line of South-to-North Water transfer Project was carried out, and a large number of laboratory tests were carried out. The expansion and shrinkage properties, shear strength change affected by dry-wet cycle, permeability coefficient and soil-water characteristic curve were studied. According to the actual working conditions of the test section, the numerical model is established, and the distribution of seepage field in the channel slope is analyzed by numerical simulation and field monitoring data to analyze the depth of the significant influence area of the channel slope. The failure mechanism of channel slope is obtained by checking and calculating the safety factor of the coupled slope. In view of its failure mechanism, a set of comprehensive protection measures for three dimensional grass planting on the slope surface of the inner and outer combined drainage geogrid are put forward, and the reinforcement mechanism measures are analyzed. In this paper, the failure mode of channel slope of South-to-North Water transfer Project is summarized, and the depth of dry and wet circulation in the atmosphere is determined. The distribution of seepage field and its safety and stability are analyzed in terms of the interaction between the upper layer of stagnant water and the atmosphere. The failure mechanism of expansive soil channel slope is revealed, and a comprehensive protection scheme is proposed, which is expected to guide the research and protection of expansive soil in South-to-North Water transfer Project.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV672;TV223
，
本文编号：2295133
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