淋滤液饱和掺砂膨润土的压缩固结特性试验研究

Experimental Research of Compression and Consolidation of the Sand-bentonite Mixture Saturated by Leachate

通过对膨润土-砂混合物进行一维压缩固结试验,研究掺砂及液相介质对膨润土压缩固结特性的影响.研究发现,膨润土-砂混合物的胀缩临界压力随掺砂率的增加而减小,两者呈现良好的线性关系;压缩系数随掺砂率的变化存在峰值,当掺砂率小于60%时,压缩系数随掺砂率的升高而升高,并呈现良好线性;掺砂率大于60%时,压缩系数随掺砂率的升高而降低;固结系数随掺砂率呈现线性变化;液相介质对掺砂膨润土的压缩固结特性有很大影响,以淋滤液饱和时,其压缩性明显升高,固结变快.试验结果对垃圾填埋场防渗缓冲层的改进提供试验依据.

Through the one-dimensional compression test of the sand-bentonite mixture, the influence of adding sand and saturated media to the characteristics of expansion and compression is studied. The results show the good linear relationship between swell-shrink critical pressure of the sand-bentonite mixture and rate of the sand, and the swell-shrink critical pressure decrease while rate increasing. The change trend of compression modulus with the rate of the sand has a peak value. The compression modulus increases as the rate increase while rate less than 60%, and vice verse when the rate higher than 60%. There is a good linear relationship between coefficient of consolidation and the rate of the sand. The types of saturated media have great impacts on characteristics of compression and consolidation of the mixture, its compression is better when the sample is saturated by percolate and consolidates more quickly. The results provide an evidence for the improvement to the impervious and buffer materials used in landfills.