冻融循环对气泡混合轻质土物理特性的影响研究

Influence of Freeze-thaw Cycles on Physical Characteristics of Air-foam Treated Lightweight Soil

针对气泡混合轻质土在寒区应用时可能受到的冻融循环作用,制备了密度为0.6 g/cm^3的气泡混合轻质土试样,通过室内试验研究了冻融循环对气泡混合轻质土体积、密度及气孔结构等物理特性的影响.试验结果表明,冻融循环作用下气泡混合轻质土的体积变化率不超过1.5%.而密度的变化则与气泡混合轻质土的初始含水量密切相关,初始含水量低时,气泡混合轻质土的密度会先随冻融循环次数的增多而变大;初始含水量高时,则规律相反.随着冻融次数的增多,气泡混合轻质土的表层结构会受到一定程度的破坏,造成孔径增大,土样表面会出现剥落的现象.

In view of the effect of freeze-thaw cycles on air-foam treated lightweight soil applied in cold areas,its volume,density and pore structure are studied in laboratory under freeze-thaw cycles based on0.6g/cm3samples.The results show that the rate of volume change of air-foam treated lightweight soil is not exceeding1.5%under freeze-thaw cycles.The original water content has great effects on the change of the density of air-foam treated lightweight soil under freeze-thaw cycles.When the original water content is low,its density increases with cycle times going up and ends up with a stable value.The rule is opposite when the original water content is high.As cycle times increase,the superficial structure of air-foam treated lightweight soil is broken to some extent,resulting in that the pores inside gets amplified,and the surface starts peeling off.