【作者】 刘丽芳；

【导师】 储才元；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2002， 博士

【摘要】 土工合成材料具有良好的物理化学性能和水工性能，是一种非常有发展前景的土建工程材料。其中的非织造土工织物，尤其是针刺非织造土工织物，因其独特的三维纤维网状结构而具有优异的过滤、排水功能，所以作为滤层材料而广泛应用于各类土木、水利工程中。但是，传统的针刺非织造土工织物是由一种或两种混合纤维组成的单层结构，在粉质粘土的工程应用中经常会造成淤堵现象，使土工织物的过滤性能大大降低，甚至失去土工织物作为滤层材料的功能。同时，在我国土工织物的应用和研究尚起步不久，产品结构单一，技术含量不高，极大地影响了土工织物的推广。针对这一现状，本论文从理论和实验两方面着重分析探讨了针刺非织造土工织物的渗透及过滤性能，并设计、研制了一种防淤堵滤层新材料。 在理论研究方面，根据Darcy定律和阻力模型理论建立了非织造土工织物结构参数与其垂直渗透系数之间的数学模型；采用Poisson Polyhedron理论分析探讨了非织造土工织物的结构与其孔径分布的关系，并以此为基础，利用随机概率分布的方法，建立了织物孔径分布与土壤颗粒通过或淤堵的概率之间的数学模型；基于在实际测试土工织物的垂直渗透系数时，有的采用单层试样，有的采用多层试样叠合的情况，本文以Darcy定律为基础从理论上分析探讨了单层与多层试样垂直渗透系数的关系；此外，本文还分析了由不同细度的纤维组成的单层经针刺复合而成的多层结构土工织物的渗透性、过滤性数学模型。 在应用研究方面，以理论分析为基础研制了一种新型防淤堵滤层材料，这是由两种粗细不同的纤维层经针刺复合而成的非织造土工织物。其中一层由较细的纤维组成，形成的孔隙较小，能够拦截大部分土壤颗粒不随水流失；另一层由较粗的纤维组成，使织物具有较高的机械强度。该织物集功能和性能于一体，尤其适用于颗粒较小的我国南方粉质粘土地区。为了探讨织物结构与其渗透、过滤性能的关系，通过改变针刺密度的方法得到了五种孔隙率不同的防淤堵滤层材料试样。 在实验方面，通过垂直渗透系数实验及淤堵实验分别验证了相应理论模型的正确性，并分别测试了本文研制的五组试样的结构性能参数和渗透性能、过滤性能以及机械性能，分析了针刺密度对织物各项性能指标的影响。另外，还选取了两种同规格的常规针刺土工织物作为对比试样，分别测试了其过滤性能及渗透性能，经对比验证了研制的滤层材料试样具有更好的渗透性和防淤堵性，以及足够的机械强度，是一种性能优异的防淤堵滤层材料。更多还原

【Abstract】 Geosynthetics, which have excellent physical, chemical, and hydraulic properties, are very promising materials and widely used in various civil construction engineering, water conservancy project, airport, railway, highway, dock, and tunnel etc. Especially for needle-punched nonwoven geotextiles used as filtering material, they have very good filtration and drainage functions because of their unique three-dimensional fiber web structure. However, needle-punched nonwoven geotextiles are traditionally single layer structure made of one or two blended fibers. So clogging is often caused in powder clay engineering, that may greatly decrease the filtering properties of geotextiles, even deprive of their functions as filtering material. At the same time, geotextiles in our country have just begun to be researched and applied, thus the related products have little difference in structures and low technological value, which infinitely affect their popularization and application. According to this situation, the permeability and filtration performance of needle-punched nonwoven geotextiles are analyzed and discussed both theoretically and experimentally in detail, and a new kind of filtering material is designed and produced in this thesis.In theoretically study, a mathematical model of the relation between structure of nonwoven geotextiles and their permeability is established on the basis of Darcy’s law and drag-force theory. The relation between structure of nonwoven geotextiles and their opening size distribution is analyzed according to Poisson Polyhedron theory, and a mathematical model of geotextile opening size distribution and the probability of soil particles passing or clogging in geotextiles is formulated. A single layer or muti-layered sample may be used in actual testing of the vertical permeability coefficient of geotextiles, so the relation between them is also theoretically analysed according to Darcy’s law. Besides, the mathematical model about permeability and filtration performance of mutilayered geotextiles consisting of fiber layer with different finess is also derived.In application research, a new anticlogging filtration material is developed. It is a kind of needle-punched nonwoven geotextile lapped over by two fiber layers withdifferent finess, therein, one layer is made of finer fiber and has smaller pores so as to retain most soil particles; the other layer is made of coarser fiber and has higher strength. The new materials have obvious advantages in function and property, and are especially suitable for powder clay areas in South China which usually have very smaller particles. Furthermore, five anticlogging filtration material samples with different porosity are produced by changing needle-punching density in order to analyze the relation between geotextile structures and their permeability and filtration performance.In experimental study, the validity of the mathematical models is experimentally verified. The structure parameters, permeability, filtration performance and mechanical properties of new anticlogging filtration material and two traditional nonwoven geotextiles are tested and compared. The relation between needle-punching density and nonwoven geotextiles properties is also discussed. The experimental results prove that the new filtration material possesses better permeability and anticlogging properties and mechanical strength and the development of this new filtration material is more significant.更多还原