为研究氮肥污染对桂林红黏土物理力学性质的影响,使用氨水(NH3·H2O)溶液对具有代表性的桂林雁山红黏土进行浸泡,考虑氨水质量分数(0,4.5%,9.0%,13.5%,18.0%)和养护时间(1,7,14 d)双因子因素,通过室内试验,分析氨水污染对桂林雁山红黏土物理力学性质的影响规律。试验结果表明:随着氨水质量分数及养护时间的增加,桂林雁山红黏土的质量、含水率、相对密度和液塑限均增大,压缩模量减小,土体压缩性增强;碱-土作用是引起红黏土物理力学性质发生变化的主要原因,其相互作用导致红黏土颗粒间的胶结物被溶解后又重新生成絮状物,使其原本稳定的结构状态发生改变。
Abstract
In the aim of exploring the effect of nitrogen fertilizer pollution on the physical and mechanical properties of red clay, the change regularity of typical red clay from Yanshan mountain, Guilin was analyzed. The red clay specimens were immersed in ammonia (NH3·H2O) solution with ammonia concentration (0, 4.5%,9.5%, 13.5%, 18%) and curing time (1 d, 7 d, 14 d) as controlling factors. Results show that the mass, moisture content, specific gravity, liquid limit and plastic limit all increased with the increase of ammonia concentration and curing time; but compression modulus decreased, while compressibility of soil is enhanced. The alkali-soil interaction is the fundamental cause of the weakening in physical and mechanical performance of alkali-contaminated red clay in Guilin area. Such interaction results in the dissolution of the binder between red clay particles and the formation of flocculants, hence changing the original stable state of the structure.
关键词
红黏土 /
氨水污染 /
物理力学性质 /
养护时间 /
试验研究 /
桂林雁山地区
Key words
red clay /
ammonia contaminated /
physical and mechanical properties /
curing time /
experimental study /
Yanshan area of Guilin
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基金
国家自然科学基金项目(41867039);广西自然科学基金项目(2017GXNSFAA198213);广西岩土力学与工程重点实验室资助项目(2015-A-01-03)
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