Study About Strength Characteristics Of Two Kinds Lime Loess In Sulfate Saline Soil Environment

Hexi Corridor is an important region of the silk road, a kind of sulfate (sulfurous) saline soil covers much in this area, this kind of saline soil has thaw collapsibility, expansibility, hygroscopicity, corrosivity and other features, has a great harm on buildings. At present the number of highway, railway, airport and building engineering construction increases in Hexi area, so for sulfate (sulfurous) saline loess’s engineering disease,it’s very necessary to conduct a study on mechanism and influence factors of it, and put forward economic and effective processing method. Lime and cement are good additive for special soil, can improve the strength and stability of the soil, study about strength characteristics of2:8-lime-loess and cement-lime-loess in sulfate environment has a important engineering practical significance for using two kinds of lime loess to deal with sulfate saline loess.In text samples of2:8-lime-loess and cement-lime-loess without sulfate were embedded in sulfate saline loess, sulfate saline soil got saturated by adding water, then a part of samples and soil were sealed,the other part were saturated again by adding water after dried to a certain water content under natural condition, so that two kinds of lime-loess were simulated in the environment of soaking and wetting-drying cycle. In this environment through a large amount of unconfined compression tests of2:8lime-loess and cement-lime-loess, it is found that strength of2:8lime-loess and cement-lime-loess presents the positive correlation to curing period and plasticity index, presents negative correlation to salinity of environment soil in the environment of soaking; strength of2:8lime-loess decreases with the increasing of times of soaking and salinity of environment soil, increase with curing period. Through observation of microstructure of2:8lime-loess samples, it is found that the microstructure of2:8lime-loess samples without soaking is turbulent pockmarked structure, the layered pockmarked structure broken into rough soil aggregate after soaking; with the increases of salinity of environment soil,the number of sodium sulfate which is columnar structure or acicular structure increases inside soil.According to the test results, when using2:8lime-loess and cement-lime-loess to deal with sulphate saline loess, it is advised that waterproofing measures should do well, and the influence of soaking times should be fully considered, the Ip of soil mixture of2:8lime-loess should be beyond8.