摘要
为研究无纺土工织物过滤黏性土在长期渗流条件下的反滤特性,采用不同单位面积质量(克重)的无纺土工织物和淤泥质粉质黏土,通过长期渗透试验,测量了土-无纺土工织物体系渗透系数随时间的变化过程,分析了渗透系数随时间的变化规律,探讨了土工织物滤层的反滤特性,并结合已有的无纺土工织物渗透系数的计算公式,提出了计算过滤后无纺土工织物渗透系数的等效孔隙率法.结果表明:土-无纺土工织物体系渗透系数随着渗透时间持续减小并趋于稳定,与时间之间符合幂函数关系;无纺土工织物滤层的透水性用渗透系数来表征,其被土粒堵塞后的孔隙率决定了渗透系数的大小;基于等效孔隙率的简化方法,计算过滤后无纺土工织物的渗透系数下降了一个数量级,但仍满足反滤准则中的透水性要求;建立的渗透系数随时间变化的幂函数关系式可以较好地反映无纺土工织物滤层的堵塞情况和透水性.
Nonwoven geotextiles with different masses per unit area(gram weight)and silty clay were used to investigate the filtration characteristics of nonwoven geotextiles filtering clayey soil during long-term seepage.The permeability coefficient of the soil-nonwoven geotextile system was measured,and the variation of the permeability coefficient with time was analyzed using a series of long-term permeability tests.The long-term seepage filtration characteristics of the soil-geotextile system were then discussed.The equivalent porosity approach for determining the permeability coefficient of filtered nonwoven geotextiles was proposed in conjunction with the current formula for calculating the permeability coefficient of nonwoven geotextiles.Results show that the permeability coefficient of the soil-nonwoven geotextile system decreases continuously with penetration time before becoming stable,and the connection between the permeability coefficient and penetration time fits the power function.The permeability of a nonwoven geotextile filter is characterized by its permeability coefficient,which is determined by its porosity after being clogged with fine particles.Based on the simplified approach of equivalent porosity,the permeability coefficient of filtered nonwoven geotextiles decreases by an order of magnitude while still meets the filtration criterion.The established power function connection of the permeability coefficient with penetration time can better reflect the clogging and permeability of nonwoven geotextile filters.
作者
杜春雪
徐超
杨阳
李明艳
DU Chunxue;XU Chao;YANG Yang;LI Mingyan(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)
出处
《华中科技大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第4期121-127,共7页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(42172297)。
关键词
土-无纺土工织物体系
反滤
长期渗透试验
渗透系数
等效孔隙率
soil-nonwoven geotextile system
filtration
long-term permeability test
permeability coefficient
equivalent porosity
