本文選題：裂隙 + 隨機場��； 參考：《哈爾濱工業(yè)大學(xué)》2013年碩士論文

【摘要】：膨脹土在我國二十多個省份都有發(fā)現(xiàn)，其中主要分布在河南、廣西和湖北等省份。因為膨脹土遇水膨脹失水收縮，因此它極易發(fā)育裂隙。裂隙可誘發(fā)邊坡失穩(wěn)、基坑坍塌等工程事故。其主要原因是裂隙的存在使得降雨入滲，造成承載力降低。為了給工程設(shè)計和地質(zhì)災(zāi)害評估提供良好的依據(jù)，對于土體抑或巖體中裂隙的水力特性進(jìn)行研究是很有必要的。 裂隙的非飽和水力特性主要包括持水曲線和滲透系數(shù)曲線兩部分。本文主要從理論分析和試驗量測兩個方面對單裂隙飽和-非飽和滲透系數(shù)進(jìn)行了深入的研究，，同時也發(fā)展了一種考慮圈閉效應(yīng)的數(shù)值方法。 數(shù)值方法方面，運用隨機場數(shù)據(jù)生成方法生成服從一定隨機場參數(shù)的裂隙開度數(shù)據(jù)，然后利用毛細(xì)定律并考慮圈閉效應(yīng)，得到了隨機單裂隙的持水曲線和滲透系數(shù)曲線。并將程序得到的持水曲線與相同開度分布參數(shù)的單裂隙試驗結(jié)果進(jìn)行了對比，對比發(fā)現(xiàn)圈閉效應(yīng)較好的解釋了試驗得到的持水曲線有較大殘余含水量的問題。 理論分析方面，建立了裂隙開度的隨機場模型；并求解了隨機單裂隙飽和-非飽和滲透系數(shù)的上限解和下限解；同時研究了裂隙開度分布隨機場參數(shù)對單裂隙滲透系數(shù)的影響。研究發(fā)現(xiàn)單裂隙飽和滲透系數(shù)在兩種極限工況條件下都受裂隙開度均值的影響最大；兩種工況條件下滲透系數(shù)開始出現(xiàn)下降時對應(yīng)的基質(zhì)吸力都取決于裂隙所能取得的最大開度值；裂隙離散尺寸越大，滲透系數(shù)下降段的斜率越大。 試驗儀器方面，研制了進(jìn)氣值較高、滲透系數(shù)較大的新型毛細(xì)柵欄。該毛細(xì)柵欄的飽和滲透系數(shù)為1.80×10-3m/s，進(jìn)氣值為0.55kPa。 利用新型毛細(xì)柵欄對穩(wěn)態(tài)非飽和滲流試驗裝置進(jìn)行改進(jìn)，從而測量得到了單裂隙的非飽和滲透系數(shù)。發(fā)現(xiàn)單裂隙的非飽和滲透系數(shù)隨著基質(zhì)吸力的改變分為三個階段變化：平穩(wěn)段、急劇下降段和緩慢下降至零段。通過對試驗結(jié)果和理論分析的對比，發(fā)現(xiàn)理論分析結(jié)果能夠很好反映試驗中裂隙滲透系數(shù)的變化趨勢和范圍；通過試驗結(jié)果與數(shù)值結(jié)果的對比發(fā)現(xiàn)這兩種方法的結(jié)果基本吻合。
[Abstract]:Expansive soil has been found in more than 20 provinces of China, mainly in Henan, Guangxi and Hubei provinces.Because expansive soil shrinks when water expands and loses water, it is easy to develop fissures.Cracks can induce slope instability, foundation pit collapse and other engineering accidents.The main reason is that the existence of cracks causes rainfall infiltration, resulting in the reduction of bearing capacity.In order to provide a good basis for engineering design and geological hazard assessment, it is necessary to study the hydraulic characteristics of fractures in soil or rock mass.The unsaturated hydraulic characteristics of fractures mainly include water retention curve and permeability coefficient curve.In this paper, the saturation-unsaturated permeability coefficient of a single fracture is studied from two aspects: theoretical analysis and experimental measurement. At the same time, a numerical method is developed to consider the trap effect.In terms of numerical method, the random field data generation method is used to generate crack opening data from certain random field parameters, and then the water holdup curve and permeability coefficient curve of random single fracture are obtained by using the law of capillary and considering the trap effect.The results of single fracture test with the same opening distribution parameters are compared with the results obtained by the program. It is found that the trap effect can explain the problem that there is a large residual water content in the water retention curve obtained by the test.In theoretical analysis, the random field model of fracture opening is established, the upper and lower bound solutions of random single fracture saturation-unsaturated permeability coefficient are solved, and the influence of random field parameters of fracture opening distribution on single fracture permeability coefficient is studied.It is found that the saturation permeability coefficient of single fracture is most affected by the mean of crack opening under two kinds of limit working conditions.When the permeability coefficient begins to decrease, the matrix suction depends on the maximum opening value obtained by the fracture, and the larger the size of the fracture is, the bigger the slope of the descending section of the permeability coefficient is.A new type of capillary fence with high air intake value and high permeability coefficient has been developed.The saturation permeability coefficient of the capillary fence is 1.80 脳 10 ~ (-3) m / s and the air intake value is 0.55 KPA.A new type of capillary fence is used to improve the steady unsaturated seepage test device, and the unsaturated permeability coefficient of a single fracture is obtained.It is found that the unsaturated permeability coefficient of a single fracture can be divided into three stages with the change of the matrix suction: steady phase, sharp descent stage and slow down to zero stage.By comparing the experimental results with the theoretical analysis, it is found that the theoretical analysis results can well reflect the variation trend and range of the fracture permeability coefficient in the test, and the comparison between the experimental results and the numerical results shows that the results of the two methods are basically consistent.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU43;TU443

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