土体在磷石膏酸液渗透作用下的物性变化试验研究  

Experimental investigation on physical properties of soil in permeation process of phosphogypsum leachate

作　　者：李国英[1,2] 白闰平[3,1,2] 米占宽[1,2] 王芳[1,2] 

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024 [2]水利部土石坝破坏机理与防控技术重点实验室,江苏南京210024 [3]同济大学地下建筑与工程系,上海200092

出　　处：《岩土工程学报》2015年第3期419-425,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金重大研究计划集成项目(91215301);中央级公益性科研院所基本科研业务费专项资金项目(Y312011,Y313012,Y314010)

摘　　要：通过开展土体在磷石膏酸液渗透作用下的三轴渗透试验、土体的物性测试试验和化学成分测定试验,研究了土体在磷石膏酸液作用下的渗透系数的变化和干密度的变化,以及土样和水样的化学成分的变化。研究结果表明:当磷石膏酸液进入土体后,与土体中水溶性无机盐类以及某些矿物质发生了化学反应,在土体孔隙中生成了水溶性极差的新物质且逐步充满土体孔隙,随着渗流时间的增长,使土样的渗透系数呈幂函数规律减小,干密度逐渐增大,磷石膏酸液的酸性减弱,土体对酸液中氢离子的吸附作用,同样也会消耗酸液中氢离子,使酸液通过土样后酸性减弱。土体在磷石膏酸液的渗透作用下,随着渗流时间的增长渗透系数逐渐变小,当渗透系数足够小时可认为在土体中形成了磷石膏酸液的天然防渗层,可阻止了酸液对土壤的进一步侵蚀。A series of triaxial permeability tests on phosphogypsum leachate, dry density tests and chemical constituent tests on soil are carried out in order to investigate the change of physical properties of soil using different test methods. The test results show that after the permeation process of phosphogypsum leachate entering the soil pore space, the acidic liquor will react with the constituents in the soil, and these chemical reactions lead to the physical property change of soil. The important changes are as follows:(1) the permeability coefficient of soil decreases in a power function mode with the increase of seepage time;(2) after the permeation process of phosphogypsum leachate, the dry density of soil decreases from the bottom up in the soil sample, and the p H value of permeation liquor increases. In addition, when the permeability coefficient of soil decreases to a value(very small) with the increase of seepage time, a natural anti-seepage layer is formed in soil, and the natural anti-seepage layer can prevent the development of the acidic liquor permeation in soil and the further erosion of soil by acidic liquor.

关 键 词：磷石膏酸液 化学反应 渗透系数 干密度 

分 类 号：TU411[建筑科学—岩土工程]