均匀反滤层下黄土的抗渗与颗粒流失特性研究  

Study on Anti-Permeability and Particle Loss Characteristics of Loess Under the Protection of Uniform Filtration Layer

作　　者：肖芳玲 张爱军[1] XIAO Fangling;ZHANG Aijun(College of Water Resources and Architectural Engineering,Northwest A ＆ F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《人民黄河》2018年第11期144-149,共6页Yellow River

基　　金：国家自然科学基金资助项目(51279171)

摘　　要：为了探讨均匀砂保护黄土的反滤准则、优化黄土的反滤层设计,以横泉水库坝体黄土为研究对象,开展了系列抗渗试验和激光粒度分析试验,研究了影响黄土抗渗强度的主要因素的权重和流失土颗粒特性。结果表明:均匀反滤层保护下的黄土抗渗强度主要与黄土的干密度、反滤层的孔隙特性有关,其中反滤层孔隙特性影响更为显著;易流失土颗粒主要是小于被保护土中值粒径d50的小颗粒,反滤层颗粒直径越小易流失土颗粒集中程度越高;激光法和比重计法所得结果具有良好的相关性,利用激光粒度分析仪代替传统的比重计具有可行性。提出了基于最小二乘法的抗渗临界坡降预估公式,证明抗渗允许坡降与临界坡降之比可以适当提高。In order to discuss the filtration criteria for protecting loess with uniform sand and to optimize the filter design of loess, series of filtration impermeability tests and laser particle size analysis test were carried out by using Hengquan Reservoir loess as samples. And the weight of the main factors affecting the anti-permeability strength of loess and the characteristics of the eroded soil particles were studied. The results show that the impermeable strength of the loess under the protection of the uniform filtration layer is mainly related to the dry density of the soil and the pore characteristics of the filter layer, the latter of which is more significant. The particle size of easily eroded soil mainly varies within the particle size of d50 of the protected soil, and with the decrease of the particle diameter of the filter layer, the concentration of the eroded particles increases. The laser particle size analysis method can effectively solve the problem that the particle of the eroded soil is too small to measure the particle gradation by the hydrometer. The regression formula based on the method of least squares is proposed to estimate the anti-permeability critical gradient, and it is proved that the ratio of the allowable impermeability gradient to the anti-permeability critical gradient can be appropriately increased.

关 键 词：黄土 抗渗 临界坡降 反滤层 有效孔隙直径 易流失土颗粒 激光粒度分析法 

分 类 号：TU411[建筑科学—岩土工程]