摘要
【目的】探讨土工布水力性能与孔隙结构之间的关系。【方法】选取了针刺短丝、聚酯长丝、超薄型3种类型共10个规格的土工布,分别用显微观测技术、渗透技术、变角排水技术和改进砂芯漏斗技术,观测了土工布孔隙结构、饱和渗透特性、非饱和持水特性等指标;建立了评估土工布孔隙结构的模型;并在此基础上分析了土工布水力性能与其孔隙结构之间的关系。【结果】①土工布的平面孔隙率和空间孔隙率都与其体积密度呈负相关关系;短丝和长丝类型的土工布的纵向孔隙率与其体积密度之间呈正相关关系;超薄型土工布的纵向孔隙率随着体积密度的增大先增大后减小。②各类土工布的垂直渗透性能都与土工布的纵向孔隙率呈正相关关系。③短丝和长丝类型的土工布的饱和度均随着土工布放置角度由小(0°)变大(90°)而降低;体积密度更大的土工布的持水能力更强;在同一饱和度下,这2种类型土工布的吸力与其厚度之间呈正相关关系。【结论】土工布的纵向孔隙率对其渗透能力和持水能力的影响相反。
【Objective】Geotextiles are often used in subsurface drainage by wrapped around the drainpipe buried in the subsurface as a filter.Their pore structure and hydraulic permeability play an important role in operation of the drainage system.The objective of this paper is to investigate the relationship between hydraulic properties of the geotextiles and their microscopic pore structure.【Method】We compared three types of geotextiles:perforated short-fibber geotextile,polyester-filament geotextile and super-thin geotextile,with 10 varieties.Microscopic structure and permeability of each geotextile under both saturated and unsaturated conditions and in different directions were measured in the laboratory from microscopic observation,permeability test rig,water drainage,as well as the improved funnel-tension plate assembly.We proposed a model to estimate the pore structure and linked it to hydraulic properties of the geotextiles.【Result】①Planar and volumetric porosity of all geotextiles increased as their density decreased.As the density increased,the porosity of the short-fibber and polyester-filament geotextiles in the transverse direction increased while that of the super-thin geotextiles increased first followed by a decline.②The higher the porosity of the geotextiles in the longitudinal direction was,the more permeable they were in the transverse direction.③Saturation of the short-fibber and polyester-filament geotextiles decreased when they were placed from 0°with the horizontal direction to 90°with the horizontal direction;the ability of the geotextiles to hold water was proportional to their volumetric density.Under the same saturation,there was a positive correlation between capillary pressure and the thickness of the first two types of the geotextiles.【Conclusion】The permeability and ability of the geotextiles to hold water are inversely proportional to their porosity in the longitudinal direction.Our results have implications for selecting geotextiles in designing subsurface drainage sy
作者
谢中意
李明思
韩寒
蓝明菊
XIE Zhongyi;LI Mingsi;HAN Han;LAN Mingju(College of Water Resources and Architectural Engineering,Shihezi University,Shihezi 832003,China)
出处
《灌溉排水学报》
CSCD
北大核心
2020年第12期87-96,共10页
Journal of Irrigation and Drainage
基金
国家自然科学基金重大项目(51790533)。
关键词
暗管排水
土工布
孔隙结构
渗透性
持水性
subsurface drainpipe
nonwoven geotextiles
pore structure
permeability
water holding capacity
