發(fā)布時間：2019-02-22 14:59

【摘要】：壓實粘土作為典型的非飽和土,因其易于施工且建設(shè)費用低,在防滲工程中常作為性能優(yōu)良的防滲劑使用,軍事工程中埋藏核廢料也常采用壓實粘土作為隔離材料。但是,在實踐中其滲透性質(zhì)難以確定,依據(jù)相關(guān)理論對非飽和土滲透特性參數(shù)作進(jìn)一步的研究是很有必要的�；诖�,本文結(jié)合國家自然科學(xué)基金面上項目(41072214)做了以下工作： (1)首先采用非飽和土聯(lián)合測試系統(tǒng),基于瞬時釋放和吸入法(TRIM法),對于不同壓實度下重塑粘土進(jìn)行了干濕試驗,根據(jù)數(shù)據(jù)采集系統(tǒng)Labview記錄的大量數(shù)據(jù)、體積含水率與時間的關(guān)系曲線、初邊值條件以及陶土板材料參數(shù),運用一維水分運移過程分析軟件HYDRUS-1D反算出水力特性參數(shù)θ(h)和K(h),進(jìn)而得到非飽和土干濕土水特征曲線和滲透函數(shù)曲線,并分析了壓實度對曲線的影響。 (2)其次對確定滲透函數(shù)的間接方法(即經(jīng)驗公式和統(tǒng)計模型法)進(jìn)行了總結(jié)；介紹了根據(jù)土水特征曲線三參數(shù)模型BrooksCorey(1964)模型和Mualem(1976)相對滲透系數(shù)計算模型(簡稱BCM模型)計算壓實粘土試樣非飽和滲透系數(shù)kw的解析法,并對3種壓實度粘土試樣的非飽和滲透系數(shù)進(jìn)行了預(yù)測；此外,還從預(yù)測原理、模型參數(shù)及獲得方法、模型預(yù)測結(jié)果等方面與采用四參數(shù)模型Van Genuchten(1978)模型和Mualem(1976)相對滲透系數(shù)計算模型(簡稱VGM模型)的數(shù)值反演預(yù)測方法進(jìn)行了對比,結(jié)果表明：兩種模型預(yù)測得到的非飽和滲透系數(shù)非常接近。 (3)最后分析了6種壓實度試樣飽和滲透系數(shù)隨壓實度的變化規(guī)律,為后面討論相對滲透系數(shù)奠定了基礎(chǔ)：同時,從中選取3種壓實度試樣對其相對滲透系數(shù)隨飽和度的變化規(guī)律進(jìn)行了分析,有助于定性討論相同干濕條件下壓實度對相對滲透系數(shù)的影響�；谝陨涎芯�,根據(jù)干化階段的試驗數(shù)據(jù)推導(dǎo)了以飽和度S和壓實度λ為自變量的歸一化滲透函數(shù)表達(dá)式；并選取壓實度為90.O%和77.8%試樣濕化階段的試驗數(shù)據(jù)對表達(dá)式進(jìn)行了驗證。驗證表明,實測滲透系數(shù)與預(yù)測滲透系數(shù)吻合度總體較好,推導(dǎo)出的考慮壓實度變化的歸一化滲透函數(shù)對壓實粘土是適用的。
[Abstract]:Compacted clay, as a typical unsaturated soil, is often used as an impermeable agent in impervious engineering because of its ease of construction and low construction cost. Compacted clay is also often used as an isolation material in military engineering. However, the permeability of unsaturated soil is difficult to be determined in practice, and it is necessary to further study the permeability parameters of unsaturated soil based on relevant theory. Based on this, this paper has done the following work in combination with project (41072214) of the National Natural Science Foundation: (1) the unsaturated soil joint test system is adopted first, based on instantaneous release and inhalation (TRIM method), The dry and wet tests of remolded clay under different compaction degrees were carried out. According to a large number of data recorded by Labview data acquisition system, the relationship curve between volume moisture content and time, initial boundary value condition and clay plate material parameters were obtained. The hydraulic characteristic parameters 胃 (h) and K (h), were calculated by using one-dimensional water migration analysis software HYDRUS-1D, and the characteristic curves and permeability function curves of dry and wet soil were obtained, and the influence of compaction degree on the curves was analyzed. (2) secondly, the indirect method of determining osmotic function (i.e. empirical formula and statistical model method) is summarized. The analytical method for calculating unsaturated permeability coefficient (kw) of compacted clay samples based on BrooksCorey (1964) model and Mualem (1976) relative permeability model (BCM model) is introduced. The unsaturated permeability coefficients of three kinds of compactness clay samples were predicted. In addition, from the prediction principle, model parameters and methods of obtaining, The prediction results of the model are compared with the numerical inversion prediction method using the four-parameter model Van Genuchten (1978) and the Mualem (1976) relative permeability calculation model (VGM model). The results show that the unsaturated permeability coefficient predicted by the two models is very close. (3) at last, the variation of saturation permeability coefficient with compaction degree is analyzed, which lays a foundation for the discussion of relative permeability coefficient: at the same time, Three kinds of compactness samples are selected to analyze the change of relative permeability coefficient with saturation, which is helpful to discuss qualitatively the influence of compaction degree on relative permeability coefficient under the same dry and wet conditions. Based on the above research, the expression of normalized permeability function with saturation S and compactness 位 as independent variables is derived according to the test data of drying stage. The experimental data of the wetting stage of 90.O% and 77.8% samples were selected to verify the expression. The results show that the measured permeability coefficient is in good agreement with the predicted permeability coefficient, and the normalized permeability function, which takes into account the change of compaction degree, is suitable for compacted clay.
【學(xué)位授予單位】：武漢理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU442

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