發(fā)布時間：2018-12-17 03:52

【摘要】：延安地區(qū)位于黃土高原的中部,黃土滑坡十分發(fā)育。根據(jù)延安地區(qū)地質(zhì)災(zāi)害詳細(xì)調(diào)查結(jié)果,延安地區(qū)現(xiàn)有滑坡1350處,幾乎全部為黃土滑坡。這些滑坡誘發(fā)因素不盡相同,有的由降雨、河流侵蝕等自然因素引起,有的由人工開挖與堆載、水庫蓄水等工程活動所引起。滑坡的誘發(fā)因素不同,其形成機(jī)理也不同,在防治上就要采取不同的防治措施。因此,研究延安地區(qū)不同誘發(fā)因素形成滑坡的機(jī)理,可以為滑坡災(zāi)害的防治提供理論依據(jù)和技術(shù)支撐,有利于制定切實可行的防災(zāi)減災(zāi)規(guī)劃,避免或減少人員傷亡和財產(chǎn)損失。本文采用對已有調(diào)查資料的分析統(tǒng)計、野外滑坡要素測量、典型滑坡點取樣測試、室內(nèi)巖土測試、數(shù)值模擬等技術(shù)方法,開展主要誘發(fā)因素引起滑坡的機(jī)理分析,所做的工作及取得的主要成果如下:(1)對延安地區(qū)地質(zhì)災(zāi)害詳細(xì)調(diào)查的結(jié)果進(jìn)行統(tǒng)計、分析,歸納總結(jié)了延安地區(qū)滑坡的發(fā)育類型;分析了延安地區(qū)形成滑坡的主要控制因素及觸發(fā)因素;(2)依據(jù)老滑坡、新滑坡的形成條件,對延安地區(qū)的黃土分別做了重塑飽和黃土的反復(fù)直剪試驗、原狀黃土在三軸條件下的剪切試驗,獲得了重塑飽和黃土和原狀黃土的強(qiáng)度特征。并對該地區(qū)的泥巖、砂巖做了單軸抗壓試驗和壓縮試驗;通過回彈試驗,分析了砂巖的結(jié)構(gòu)面強(qiáng)度。(3)在分析了降雨入滲方式、入滲規(guī)律的基礎(chǔ)上,以富縣吉子現(xiàn)鄉(xiāng)滑坡、閻家溝滑坡、延煉滑坡為典型實例,通過數(shù)值模擬,再現(xiàn)了降雨通過黃土孔隙、節(jié)理入滲,降雨通過黃土中卸荷裂縫、落水洞等集中通道流入,以及降雨通過水分逐漸往下遷移分別形成滑坡的過程,分析了不同入滲方式形成滑坡的機(jī)理。(4)以庵里滑坡、印臺山滑坡以及洛川加油站滑坡為例,通過數(shù)值模擬,分析了溯源侵蝕、河流側(cè)蝕及河流或溝谷下蝕形成滑坡的過程,通過對比各個階段滑動面上應(yīng)力及抗剪強(qiáng)度的變化,解釋了河流不同侵蝕方式形成滑坡的機(jī)理。并模擬了滑坡的運動過程,獲得了滑坡的滑動范圍及運動距離。(5)根據(jù)水庫蓄水在迎水岸誘發(fā)滑坡的特征,概化典型模型,數(shù)值模擬了在迎水岸庫水位上漲及驟降時不同時段孔隙水壓力及剪應(yīng)力的變化,分析了滑面不同位置剪應(yīng)力及抗剪強(qiáng)度的關(guān)系,以及岸坡穩(wěn)定性隨時間的變化,揭示了迎水岸水庫蓄水誘發(fā)滑坡的機(jī)理。以趙家岸滑坡作為背水岸滑坡的實例,模擬分析了庫水位上漲和下降時孔隙水壓力及應(yīng)力的變化,揭示了水庫蓄水在背水岸誘發(fā)滑坡的機(jī)理。(6)選取三畝臺滑坡、南窯村高邊坡、龍首村高邊坡三個典型案例,對人工開挖引起的新滑坡進(jìn)行數(shù)值分析,解釋了人工開挖形成新滑坡的機(jī)理。以王窯村滑坡為例,解釋了開挖導(dǎo)致老滑坡復(fù)活的機(jī)理。以袁和莊滑坡為例,分析了堆載后坡體應(yīng)力及抗剪強(qiáng)度的變化,解釋了堆載導(dǎo)致的滑坡形成機(jī)理。
[Abstract]:Yan'an area is located in the middle of the Loess Plateau, loess landslide is very developed. According to the detailed investigation results of geological hazards in Yanan area, there are 1350 landslides in Yanan area, almost all of which are loess landslides. The induced factors of these landslides are different, some are caused by natural factors such as rainfall and river erosion, and some are caused by engineering activities such as artificial excavation and heaps, reservoir water storage and so on. The induced factors of landslide are different, and the formation mechanism of landslide is different, so different measures should be taken to prevent and cure landslide. Therefore, studying the mechanism of landslide formation by different induced factors in Yan'an area can provide theoretical basis and technical support for the prevention and control of landslide disasters, which is helpful to formulate feasible plans for disaster prevention and mitigation and to avoid or reduce casualties and property losses. In this paper, the analysis and statistics of the existing investigation data, the measurement of landslide elements in the field, the sampling test of typical landslide points, the indoor geotechnical test and numerical simulation are used to analyze the mechanism of the landslide caused by the main induced factors. The work and main results obtained are as follows: (1) the results of detailed investigation of geological hazards in Yanan area are statistically analyzed, and the development types of landslide in Yanan area are summarized. The main controlling factors and triggering factors of landslide formation in Yan'an area are analyzed. (2) according to the forming conditions of the old landslide and the new landslide, the repeated direct shear tests of the remolded saturated loess and the shear test of the undisturbed loess under the triaxial condition have been made on the loess in Yan'an area. The strength characteristics of remolded saturated loess and undisturbed loess are obtained. The uniaxial compression test and compression test are also done for the mudstone and sandstone in this area. The structural surface strength of sandstone is analyzed by springback test. (3) based on the analysis of rainfall infiltration mode and infiltration law, taking Jizixian landslide, Yanlian landslide and Yanjiagou landslide in Fuxian County as typical examples, numerical simulation is carried out. It reappears the process of rainfall flowing through loess pore, joint infiltration, rainfall through loess unloading crack, falling water tunnel and other concentrated channels, and rainfall gradually moving down to form landslide. The mechanism of landslide formation in different infiltration modes is analyzed. (4) taking the Anli landslide, Yintai Mountain landslide and Luochuan Gas Station landslide as examples, the traceability erosion is analyzed by numerical simulation. The process of river side erosion and river or valley erosion to form landslide is discussed. By comparing the stress and shear strength on the sliding surface of each stage, the mechanism of river landslide formation with different erosion modes is explained. The movement process of landslide is simulated, and the sliding range and distance of landslide are obtained. (5) according to the characteristics of landslide induced by reservoir impoundment in Yingshui bank, the typical model is generalized. The variation of pore water pressure and shear stress in different periods when the water level of Yingshui reservoir rises and drops is numerically simulated. The relationship between shear stress and shear strength at different positions of sliding surface and the variation of slope stability with time are analyzed. The mechanism of landslide induced by impoundment of Yingshuian reservoir is revealed. Taking Zhaojiaban landslide as an example of backwater bank landslide, the variation of pore water pressure and stress during the rise and fall of reservoir water level is simulated and analyzed, and the mechanism of reservoir water storage inducing landslide in backwater bank is revealed. (6) selecting Sanmu landslide. Three typical cases of high slope in Nanyao village and high slope in Longshou village are analyzed numerically. The mechanism of forming new landslide caused by artificial excavation is explained. Taking Wangyaocun landslide as an example, the mechanism of old landslide resurrection caused by excavation is explained. Taking Yuanhezhuang landslide as an example, the variation of slope stress and shear strength after heaped load is analyzed, and the formation mechanism of landslide caused by surcharge is explained.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：P642.22

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本文編號：2383604