为探究无纺土工布孔径在侧向限制的拉伸作用下所受的影响,基于孔径分布的数量概率密度函数,推导了表征筛分颗粒质量分布的概率密度表达式,并考虑受侧限单向拉伸时的无纺布尺寸变化,得出侧限单向拉应变作用下的无纺布孔径累积分布理论公式。将3种不同厚度的短纤针刺无纺土工布侧边进行限制,单向拉伸至应变为0%、3%、5%和10%后分别取样进行消除静电影响的干筛试验,测量初始及各应变下无纺布孔径分布结果并与理论值对比。结果表明,无纺土工布孔径分布曲线随侧限单向拉应变增加而右移,各个特征孔径均增大,且无纺布孔径随织物厚度增加而减小。相较于筛分颗粒面积分布的累积概率表达式,基于筛分颗粒质量分布的理论孔径累积分布概率表达式更好地预测了干筛试验曲线变化规律。
Abstract
Nonwoven geotextiles used as filters are commonly subjected to laterally constrained tensile loads in practice. A theoretical solution is developed to study the pore size distribution of nonwoven geotextiles under laterally constrained uniaxial tension. The theoretical solution is based on a fiber network model, whereby the probabilistic sieving problem is equivalent to a mass-based probability of retention which is modified from a number-based probability density. Three different needle-punched nonwoven geotextiles are subjected to the uniaxial tensile strains with lateral confinement. The pore sizes of unstrained geotextiles and geotextiles under strains 3%, 5% and 10%, respectively, are obtained from dry sieving test after eliminating electrostatic effects. The experimental results present an accurate prediction of theoretical equations in pore size distribution with laterally constrained uniaxial tensile strain. The pore size distribution curves move towards right with the increase of tensile strain under lateral confinement, which results in the increase in characteristic pore diameters.
关键词
孔径概率分布 /
无纺土工布 /
侧限单向拉伸 /
孔径累积分布理论 /
干筛试验 /
特征孔径
Key words
pore size probability distribution /
nonwoven geotextile /
laterally constrained uniaxial tension /
cumulative pore size distribution theory /
dry sieving test /
characteristic pore size
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基金
浙江省基础公益研究计划项目(LGG22E080002);浙江省水利科技计划重点项目(RB2027)
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