Determination of effective porosity of soil materials
Determination of effective porosity of soil materials
复制标题
土壤材料有效孔隙度的测定
DOI：
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
J. F. Mcbride
中科院分区：
文献类型：
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作者：
R. Horton;M. L. Thompson;J. F. Mcbride
危险废物处置垃圾填埋场需要用压实的土壤材料建造衬垫，以帮助防止危险废物的迁移。压实土壤衬砌的性能在一定程度上是孔隙度的函数。孔隙率很重要，因为材料通过衬里的传输将通过孔隙空间发生。该项目的主要目的是研究压实土材料的孔隙空间，并估算有效孔隙率，有效孔隙率是渗滤液最快速传输的孔隙空间部分。采用压汞测孔、吸水解吸和图像分析等方法研究了耕作、黄土和古土壤三种土壤材料的孔隙空间。这些分析提供了累积的孔隙度曲线，根据该曲线可以估计土壤样品的孔隙大小分布。根据压实土材料的孔隙大小分布和孔隙连续性模型，发展了估算压实土材料有效孔隙率的理论。压实耕地、黄土和古土壤的有效孔隙率分别为0.04、0.08和0.09。这些值占总孔隙率的10%到20%。为了验证估算的有效孔隙率，对压实土壤样品的氯离子传播时间进行了实测值和预测值的比较。预测的有效孔隙率是合理的，因为预测的Cl1突破时间与在压实耕地、黄土和古土壤材料中测得的首次突破时间相似。对于本研究中使用的三种土壤材料，在基于Darcy方程的计算中使用有效孔隙度时，预测的首次突破时间比基于Darcy方程的利用总孔隙度的计算提前5-10倍。本报告由爱荷华州立大学根据合作协议CR-811093-01-0提交，由美国环境保护局赞助。本报告所涉期间为83年10月1日至86年4月30日，截至1985年12月31日已完成工作。
Hazardous waste disposal landfills require liners constructed of compacted soil material to help prevent the migration of hazardous wastes. The performance of a compacted soil liner is partly a function of the porosity. Porosity is important because the transport of materials through the liner will occur via the pore space. The main purpose of this project is to study the pore spaces of compacted soil materials and to estimate the effective porosity, which is the portion of the pore space where the most rapid transport of leachate occurs. The pore space of three soil materials, till, loess, and paleosol, is studied by using mercury intrusion porosimetry, water desorption, and image analysis. These analyses provide cumulative porosity curves from which the pore size distribution of a soil sample may be estimated. Theory is developed to estimate the effective porosity of a compacted soil material based upon a model of its pore size distribution and pore continuity. The effective porosities of the compacted till, loess, and paleosol materials are estimated to be 0.04, 0.08, and 0.09, respectively. These values are 10 to 20% of the total porosities. Comparisons between measured and predicted Cl travel times through compacted soil samples are made in order to verify the estimated effective porosities. The estimated effective porosities are reasonable because predicted Clfirst breakthrough times are similar to the measured first breakthrough times in compacted till, loess, and paleosol materials. For the three soil materials used in this study., predicted first breakthrough times are 5 to 10 times earlier when effective porosity is used in the Darcy-equation-based calculations as compared to Darcy-equation-based calculations that u~ilize total porosity. This report was submitted in fulfillment of cooperative agreement CR-811093-01-0 by Iowa State University under the sponsorship of the U.S. Environmental Protection Agency. This report covers a period from 10/1/83 to 4/30/86, and work was completed as of 12/31/85.