复合土工膜环向约束球形鼓胀变形试验研究
发布时间：2018-07-14 12:34
【摘要】：复合土工膜已在水库、人工湖、固体垃圾填埋场等库底水平防渗系统中得到广泛应用。对于库底采用复合土工膜水平防渗的水库或固体垃圾填埋场,由于地下水位上升、复合土工膜缺陷渗漏等多种原因,使膜下非饱和土层中的气体聚集、上升,并在复合土工膜膜下形成有压气体,导致复合土工膜出现局部鼓胀变形甚至破坏的现象,可归类为复合土工膜气胀现象,复合土工膜气胀变形会进一步加剧库水渗漏,并影响水库防渗安全。因此,研究复合土工膜气胀变形的力学特征,对于保证复合土工膜库盘防渗的安全性和可靠性具有重要的现实意义。论文总结了复合土工膜气胀变形的特征,分析了复合土工膜气胀变形的影响因素的,推导出了复合土工膜的应力应变计算公式,利用气胀变形专用试验设备,进行了土工膜、土工布和复合土工膜的气胀变形试验研究,研究了设备直径、加载频率对土工膜、土工布和复合土工膜气胀变形特性的影响,以及复合土工膜气胀变形的应力应变规律、胀破强度和气胀破坏时最大冠顶高度等,主要研究内容和成果如下:(1)复合土工膜气胀变形的主要影响因素分别为设备孔径、加载速率和膜布结合方式等。(2)分析了复合土工膜环向约束鼓胀变形特征,基于鼓胀变形的几何关系和力学原理,推导了复合土工膜环状约束球形气胀变形的应力-应变公式。因为应力和应变公式的推导与材料本身的力学性质无关,因此该公式适用于所有土工合成材料的气胀变形应力应变的计算。由推导的应力应变公式可知:应力σ的大小与约束法兰盘直径,冠顶高度,样品厚度和胀破强度有关,而应变ε仅与约束法兰盘直径和冠顶高度有关。(3)通过土工膜的气胀变形及在相同条件下的土工膜与放置其下面土工布的胀破试验数据分析可得出,下面的土工布不承受力学作用,主要起到保护土工膜刺穿、延长复合土工膜的使用寿命的作用,而承担主要荷载的是上面的土工布以及中间的土工膜。(4)复合土工膜鼓胀隆起的面积越小、速率越快,其气胀压力值越大,冠顶高度越小;冠顶高度的极限值与复合土工膜的极限延伸率有关;气胀压力值的大小关系与冠顶高度、应力应变的大小关系相反。(5)复合土工膜气胀变形过程中应力-应变曲线可划分为四个阶段分别是弹性阶段、屈服阶段、强化阶段和胀破拉断阶段。(6)当土工膜与土工布紧密结合时,膜和布相互影响使其整体性更强、力学性能更优,因而使复合土工膜所能承受的应力和应变大于土工膜、土工布的最大应力和应变。
[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.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV49
本文编号：2121657
[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.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV49
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