南水北調(diào)膨脹土渠道邊坡穩(wěn)定可靠度研究
發(fā)布時間：2018-08-13 19:48
【摘要】：膨脹土富含蒙脫石等多種強親水性礦物質(zhì)，受環(huán)境干濕變化影響很大，在膨脹土地基上開挖的渠道，邊坡失水時會產(chǎn)生收縮，土體間的凝聚力下降，導致邊坡表面開裂、剝落，而膨脹土邊坡吸水時，又會產(chǎn)生強烈的膨脹變形，甚至會出現(xiàn)滑塌現(xiàn)象。 我國南水北調(diào)中線總干渠工程長達1200多km，，受地形地質(zhì)條件的因素限制，沿線位于膨脹土層上的渠段長達346.85km，約占總干渠全長的30%。膨脹土渠段施工與運行的安全可靠對全線工程安全施工、安全運行具有十分重要的影響。同時，對膨脹土工程特性的研究以及膨脹土地基上工程安全的研究，一直是工程界一個世界性課題。 在膨脹土地基上開挖的渠道邊坡，其滲透性、穩(wěn)定性將受到諸多不確定性因素影響，如渠坡內(nèi)不同的地下水位情況、渠道內(nèi)不同輸水工況均不確定性地影響渠坡的滲透和穩(wěn)定性能。 本文以南水北調(diào)中線總干渠某標段膨脹土渠道為背景，進行了膨脹土渠道邊坡穩(wěn)定可靠度研究及FLAC-SLOPE有限元軟件模擬計算。首先將影響邊坡穩(wěn)定的諸多因素處理為隨機變量，建立了邊坡穩(wěn)定可靠度模型，由JC法計算穩(wěn)定可靠指標及諸多因素變異對可靠指標的影響；在此基礎上，進一步運用FLAC-SLOPE軟件進行有限元計算分析。 考慮到渠坡滲流排水設施可能會可靠有效，或由于某種原因發(fā)生失效的情況，地下水位考慮了在渠道坡頂處地面以下埋深1m和6m情況；渠道內(nèi)水深考慮了渠內(nèi)無水（即施工竣工期）、渠道滿水（即渠內(nèi)水深為設計水深6m）、渠道內(nèi)水深為1/3設計水深（即渠內(nèi)水深為2m）三種工況。 綜合分析理論計算結果與FLAC-SLOPE模擬計算結果，得到了有關膨脹土挖方渠坡潛在的危險滑裂面形態(tài)，滑坡失穩(wěn)的最不利部位、邊坡穩(wěn)定失效概率區(qū)間及土壤特性參數(shù)變異對邊坡穩(wěn)定可靠度的影響等結論。其結果可為工程安全提出有益的建議。
[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.
【學位授予單位】：河北工程大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV68;TV223
本文編號：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.
【學位授予單位】：河北工程大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV68;TV223
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本文編號：2181998
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