碱污染红黏土土工试验方法温度效应影响研究

摘要

碱污染土碱土作用过程对温度极为敏感,实践中发现按现行《土工试验规程》测定含水率、液塑限和比重时,烘干或加热过程都会严重影响参数测定准确性,为了系统的研究这一影响规律,用不同浓度的碱液拌合制作高、中、低含水率红黏土,在不同温度下进行含水率、液塑限和比重的测定.结果表明:各测定值随着温度的升高,含水率值偏高,液限值和塑性指数值减小,塑限值变化不大;预制含水率不同时,变化规律有差异;碱液浓度越大偏差的程度越大;比重测定受取土和煮沸排气两个过程的影响,直接烘干土偏大,煮沸排气风干土偏小.温度效应通过影响初期侵蚀和中期胶结两个碱土作用过程来影响土工试验方法,建议在碱污染土的含水率、界限含水率测定时,用低温风干再烘干的方法.在比重测定时干土制做用先风干后烘干的方法,排气用中性液体真空抽气法.结论为考虑温度效应的污染土研究做准备.%Alkali contaminated soil is extremely sensitive to temperature during the process of the alkaline-earth effects.In practice,it is found that the drying or heating process can seriously affect the accuracy of parameter measurement in determining the moisture content,liquid plastic limit and specific gravity according to the existing《Test methods of soils》.In order to study the influence law of the system,the red clay is mixed with different concentrations of alkali for reaching high,medium and low water content,and then the water content,liquid plastic limit and specific gravity are determined at different temperatures.Measurement results show that: with the increase of temperature,the value of water content is higher,the value of liquid limit and plastic index decrease,and the plastic limit is not changed;there are differences in the law of change,because the pre-made water content is not the same;The bigger the alkali concentration the bigger the degree of deviation;measuring the specific gravity is affected by borrowing soil and boiling exhaust,so that the proportion of direct drying soil is large,and the proportion of the exhaust air dry boil is small.The effect of temperature affected the soil test method by both initial erosion and mid cementation.It is suggested that take the method of airing with low temperature and then dry for determining water content and boundary water content of the alkali contaminated soil.In the determination of specific gravity,using the method of airing soil before drying for producing dry soil,and pumping neutral liquid vacuum for exhausting gas.The conclusion will be used for the study of contaminated soil considering temperature effect.