南水北调膨胀土渠道边坡稳定可靠度研究
发布时间：2018-08-13 19:48
【摘要】：膨胀土富含蒙脱石等多种强亲水性矿物质，受环境干湿变化影响很大，在膨胀土地基上开挖的渠道，边坡失水时会产生收缩，土体间的凝聚力下降，导致边坡表面开裂、剥落，而膨胀土边坡吸水时，又会产生强烈的膨胀变形，甚至会出现滑塌现象。 我国南水北调中线总干渠工程长达1200多km，，受地形地质条件的因素限制，沿线位于膨胀土层上的渠段长达346.85km，约占总干渠全长的30%。膨胀土渠段施工与运行的安全可靠对全线工程安全施工、安全运行具有十分重要的影响。同时，对膨胀土工程特性的研究以及膨胀土地基上工程安全的研究，一直是工程界一个世界性课题。 在膨胀土地基上开挖的渠道边坡，其渗透性、稳定性将受到诸多不确定性因素影响，如渠坡内不同的地下水位情况、渠道内不同输水工况均不确定性地影响渠坡的渗透和稳定性能。 本文以南水北调中线总干渠某标段膨胀土渠道为背景，进行了膨胀土渠道边坡稳定可靠度研究及FLAC-SLOPE有限元软件模拟计算。首先将影响边坡稳定的诸多因素处理为随机变量，建立了边坡稳定可靠度模型，由JC法计算稳定可靠指标及诸多因素变异对可靠指标的影响；在此基础上，进一步运用FLAC-SLOPE软件进行有限元计算分析。 考虑到渠坡渗流排水设施可能会可靠有效，或由于某种原因发生失效的情况，地下水位考虑了在渠道坡顶处地面以下埋深1m和6m情况；渠道内水深考虑了渠内无水（即施工竣工期）、渠道满水（即渠内水深为设计水深6m）、渠道内水深为1/3设计水深（即渠内水深为2m）三种工况。 综合分析理论计算结果与FLAC-SLOPE模拟计算结果，得到了有关膨胀土挖方渠坡潜在的危险滑裂面形态，滑坡失稳的最不利部位、边坡稳定失效概率区间及土壤特性参数变异对边坡稳定可靠度的影响等结论。其结果可为工程安全提出有益的建议。
[Abstract]:Expansive soil is rich in many kinds of strong hydrophilic minerals such as montmorillonite, which is greatly affected by environmental dry-wet changes. When the channel is excavated on the expansive soil foundation, the slope will shrink when it loses water, and the cohesive force among the soil will decrease, which will lead to the surface cracking and spalling of the slope. When the expansive soil slope absorbs water, it will produce strong swelling deformation and even collapse. The total trunk canal project of the middle route of South-to-North Water diversion Project in China is more than 1200 km, which is restricted by the factors of topography and geology, and the canal section located on the expansive soil layer along the line is 346.85 km, which accounts for about 30% of the total length of the main canal. The safety and reliability of the construction and operation of expansive soil canal section have a very important influence on the safe construction and safe operation of the whole railway project. At the same time, the research on engineering characteristics of expansive soil and engineering safety on expansive soil foundation has been a worldwide subject in engineering field. The permeability and stability of the canal slope excavated on the expansive soil foundation will be affected by many uncertain factors, such as the different groundwater level in the channel slope. The permeability and stability of channel slope are affected by different water conveyance conditions. In this paper, based on the expansive soil channel in the main trunk channel of the South-to-North Water transfer Project, the reliability of the expansive soil channel slope is studied and the FLAC-SLOPE finite element software is used to simulate the stability of the expansive soil channel slope. Firstly, the factors affecting slope stability are treated as random variables, and the model of slope stability reliability is established. The stability reliability index and the influence of variation of many factors on the reliability index are calculated by JC method. The finite element analysis is carried out by using FLAC-SLOPE software. Considering that the seepage drainage facilities on the channel slope may be reliable and effective, or for some reason failure, the underground water level takes into account the buried depth of 1m and 6m below the top of the canal slope; The water depth in the canal considers three conditions: no water in the canal (that is, the completion period of construction), full water in the channel (that is, the design water depth is 6 m inside the canal), and the water depth in the channel is one third of the designed water depth in the canal (that is, the water depth in the canal is 2m). By synthesizing the theoretical calculation results and the FLAC-SLOPE simulation results, the potential dangerous slip surface morphology of expansive soil excavating channel slope and the most unfavorable part of landslide instability are obtained. The effect of slope failure probability interval and soil characteristic parameter variation on slope stability reliability is discussed. The results can provide useful suggestions for engineering safety.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV68;TV223
本文编号：2181998
[Abstract]:Expansive soil is rich in many kinds of strong hydrophilic minerals such as montmorillonite, which is greatly affected by environmental dry-wet changes. When the channel is excavated on the expansive soil foundation, the slope will shrink when it loses water, and the cohesive force among the soil will decrease, which will lead to the surface cracking and spalling of the slope. When the expansive soil slope absorbs water, it will produce strong swelling deformation and even collapse. The total trunk canal project of the middle route of South-to-North Water diversion Project in China is more than 1200 km, which is restricted by the factors of topography and geology, and the canal section located on the expansive soil layer along the line is 346.85 km, which accounts for about 30% of the total length of the main canal. The safety and reliability of the construction and operation of expansive soil canal section have a very important influence on the safe construction and safe operation of the whole railway project. At the same time, the research on engineering characteristics of expansive soil and engineering safety on expansive soil foundation has been a worldwide subject in engineering field. The permeability and stability of the canal slope excavated on the expansive soil foundation will be affected by many uncertain factors, such as the different groundwater level in the channel slope. The permeability and stability of channel slope are affected by different water conveyance conditions. In this paper, based on the expansive soil channel in the main trunk channel of the South-to-North Water transfer Project, the reliability of the expansive soil channel slope is studied and the FLAC-SLOPE finite element software is used to simulate the stability of the expansive soil channel slope. Firstly, the factors affecting slope stability are treated as random variables, and the model of slope stability reliability is established. The stability reliability index and the influence of variation of many factors on the reliability index are calculated by JC method. The finite element analysis is carried out by using FLAC-SLOPE software. Considering that the seepage drainage facilities on the channel slope may be reliable and effective, or for some reason failure, the underground water level takes into account the buried depth of 1m and 6m below the top of the canal slope; The water depth in the canal considers three conditions: no water in the canal (that is, the completion period of construction), full water in the channel (that is, the design water depth is 6 m inside the canal), and the water depth in the channel is one third of the designed water depth in the canal (that is, the water depth in the canal is 2m). By synthesizing the theoretical calculation results and the FLAC-SLOPE simulation results, the potential dangerous slip surface morphology of expansive soil excavating channel slope and the most unfavorable part of landslide instability are obtained. The effect of slope failure probability interval and soil characteristic parameter variation on slope stability reliability is discussed. The results can provide useful suggestions for engineering safety.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV68;TV223
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本文编号：2181998
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