膨润土改性天然粘土防渗材料的研究

膨润土具有很好的防渗和吸附性能．在华北黄土和华南红土中加入一定量的膨润土，以增强衬层材料的防渗性能．研究了膨润土加入量对土样抗压强度和压实土样渗透系数的影响，压实含水率、压实干密度等因素对压实粘土渗透性能的影响．实验原理为Darcy定理．实验结果表明：对于黄土，膨润土合量为6％—7％时，抗压强度最大．选择大于强度最优含水率2％的压实含水率有利于提高黄土及其改性粘土的防渗功能．对于红土，加入8％的膨润土对其抗压强度有很大的改善，抗渗性能有着较大的提高，渗透系数只相当于原土的1／30．选用24％左右的压实含水率可以使红土(及其改性粘土)的抗压性能与防渗性能同时优化．

Study on Bentonite Enhanced Soil as Landfill Materials

Loess and laterite distributed widely in the northern and southern China cannot be directly used as the natural barrier to isolate the solid waste because of their high hydraulic conductivity. In this paper, they are enhanced by bentonite to improve their performance. The effects of bentonite percentage on compressive strength and permeability of the compacted soil and the effects of moisture and density of the compacted soil on its permeability were studied. For the loess, the compressive strength reaches the peak when the bentonite is between 6% and 7%. It is helpful to improve the hydraulic performance of the original and enhanced loess if the water percentage of the compacted soil is by 2% higher than that with the optimum compressive strength. For the laterite, 8% of bentonite can significantly improve its compressive strength and hydraulic performance. The permeability coefficient of the enhanced laterite is only one-thirtieth of that of the original laterite. It is helpful to improve the hydraulic performance and compressive strength of the original and enhanced laterite if the water percentage of the compacted soil is about 24%. The results in this paper will be good to develop the bentonite-enhanced soils as landfill materials.