【摘要】：復(fù)合土工膜已在水庫、人工湖、固體垃圾填埋場等庫底水平防滲系統(tǒng)中得到廣泛應(yīng)用。對于庫底采用復(fù)合土工膜水平防滲的水庫或固體垃圾填埋場,由于地下水位上升、復(fù)合土工膜缺陷滲漏等多種原因,使膜下非飽和土層中的氣體聚集、上升,并在復(fù)合土工膜膜下形成有壓氣體,導(dǎo)致復(fù)合土工膜出現(xiàn)局部鼓脹變形甚至破壞的現(xiàn)象,可歸類為復(fù)合土工膜氣脹現(xiàn)象,復(fù)合土工膜氣脹變形會進一步加劇庫水滲漏,并影響水庫防滲安全。因此,研究復(fù)合土工膜氣脹變形的力學(xué)特征,對于保證復(fù)合土工膜庫盤防滲的安全性和可靠性具有重要的現(xiàn)實意義。論文總結(jié)了復(fù)合土工膜氣脹變形的特征,分析了復(fù)合土工膜氣脹變形的影響因素的,推導(dǎo)出了復(fù)合土工膜的應(yīng)力應(yīng)變計算公式,利用氣脹變形專用試驗設(shè)備,進行了土工膜、土工布和復(fù)合土工膜的氣脹變形試驗研究,研究了設(shè)備直徑、加載頻率對土工膜、土工布和復(fù)合土工膜氣脹變形特性的影響,以及復(fù)合土工膜氣脹變形的應(yīng)力應(yīng)變規(guī)律、脹破強度和氣脹破壞時最大冠頂高度等,主要研究內(nèi)容和成果如下:(1)復(fù)合土工膜氣脹變形的主要影響因素分別為設(shè)備孔徑、加載速率和膜布結(jié)合方式等。(2)分析了復(fù)合土工膜環(huán)向約束鼓脹變形特征,基于鼓脹變形的幾何關(guān)系和力學(xué)原理,推導(dǎo)了復(fù)合土工膜環(huán)狀約束球形氣脹變形的應(yīng)力-應(yīng)變公式。因為應(yīng)力和應(yīng)變公式的推導(dǎo)與材料本身的力學(xué)性質(zhì)無關(guān),因此該公式適用于所有土工合成材料的氣脹變形應(yīng)力應(yīng)變的計算。由推導(dǎo)的應(yīng)力應(yīng)變公式可知:應(yīng)力σ的大小與約束法蘭盤直徑,冠頂高度,樣品厚度和脹破強度有關(guān),而應(yīng)變ε僅與約束法蘭盤直徑和冠頂高度有關(guān)。(3)通過土工膜的氣脹變形及在相同條件下的土工膜與放置其下面土工布的脹破試驗數(shù)據(jù)分析可得出,下面的土工布不承受力學(xué)作用,主要起到保護土工膜刺穿、延長復(fù)合土工膜的使用壽命的作用,而承擔(dān)主要荷載的是上面的土工布以及中間的土工膜。(4)復(fù)合土工膜鼓脹隆起的面積越小、速率越快,其氣脹壓力值越大,冠頂高度越小;冠頂高度的極限值與復(fù)合土工膜的極限延伸率有關(guān);氣脹壓力值的大小關(guān)系與冠頂高度、應(yīng)力應(yīng)變的大小關(guān)系相反。(5)復(fù)合土工膜氣脹變形過程中應(yīng)力-應(yīng)變曲線可劃分為四個階段分別是彈性階段、屈服階段、強化階段和脹破拉斷階段。(6)當(dāng)土工膜與土工布緊密結(jié)合時,膜和布相互影響使其整體性更強、力學(xué)性能更優(yōu),因而使復(fù)合土工膜所能承受的應(yīng)力和應(yīng)變大于土工膜、土工布的最大應(yīng)力和應(yīng)變。
[Abstract]:Composite geomembrane has been widely used in reservoir, artificial lake, solid waste landfill and other reservoir bottom level seepage control system. For reservoirs or solid waste landfills where composite geomembrane is used for horizontal seepage prevention, the gas in unsaturated soil under the film accumulates and rises due to the rise of groundwater level and the leakage of composite geomembrane defects. The formation of pressurized gas under the composite geomembrane leads to local bulging deformation and even destruction of the composite geomembrane, which can be classified as the inflating phenomenon of the composite geomembrane, and the gas expansion deformation of the composite geomembrane will further aggravate the leakage of reservoir water. It also affects the safety of reservoir seepage control. Therefore, it is of great practical significance to study the mechanical characteristics of inflating deformation of composite geomembrane in order to ensure the safety and reliability of seepage prevention of composite geomembrane. In this paper, the characteristics of inflating deformation of composite geomembrane are summarized, the influencing factors of inflating deformation of composite geomembrane are analyzed, the formula of stress and strain calculation of composite geomembrane is deduced, and the geomembrane is carried out by using the special test equipment of inflating deformation. Experimental study on inflatable deformation of geotextile and composite geomembrane is carried out. The effects of equipment diameter and loading frequency on the inflating deformation characteristics of geotextile, geotextile and composite geomembrane, as well as the stress-strain law of the inflatable deformation of composite geomembrane are studied. The main research contents and results are as follows: (1) the main factors influencing the inflating deformation of composite geomembrane are the aperture of the equipment respectively. (2) the characteristics of circumferential confined bulging deformation of composite geomembrane are analyzed. Based on the geometric relation and mechanical principle of bulging deformation, the stress-strain formula of spherical inflating deformation with circular confinement of composite geomembrane is derived. Since the derivation of the stress and strain formula is independent of the mechanical properties of the material itself, the formula is applicable to the calculation of the stress and strain of inflatable deformation of all geosynthetics. From the derived formula of stress and strain, it can be concluded that the magnitude of stress 蟽 is related to the diameter of confined flange, the height of crown top, the thickness of sample and the strength of dilatation. The strain 蔚 is only related to the diameter of the confined flange and the height of the crown top. (3) by analyzing the inflating deformation of the geomembrane and the swelling and breaking test data of the geomembrane under the same conditions and placing the geotextile under the same condition, it can be concluded that the strain 蔚 is related to the diameter of the flange and the height of the crown top. The following geotextile has no bearing capacity, mainly plays the role of protecting geotextile piercing and prolonging the service life of composite geomembrane. The main load is the geotextile on the top and the geomembrane in the middle. (4) the smaller the bulging area of the composite geomembrane, the faster the rate, the bigger the inflating pressure and the lower the crown height; The limit value of crown top height is related to the limit elongation of composite geomembrane, and the relation of inflating pressure value to crown top height, The stress-strain relationship is opposite. (5) the stress-strain curve of composite geomembrane can be divided into four stages: elastic stage and yield stage. (6) when the geomembrane and the geotextile are closely combined, the interaction between the film and the fabric makes the integrity stronger and the mechanical properties better, so that the stress and strain of the composite geomembrane are larger than that of the geomembrane. Maximum stress and strain of geotextile.
【學(xué)位授予單位】：濟南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV49

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