不同龄期下石灰改良土持水特性的温度效应

Temperature effect on the water retention curve of lime-treated soil during curing

石灰改良是一种经济、有效的土质改良方法,在实际工程中,改良土由于长期暴露在复杂气候与环境中,普遍存在长期强度衰减现象。土水特征曲线是研究土体水分运移规律及其水力性能的重要途径。为研究温度和养护龄期对石灰改良土土水特征曲线的影响规律,制备了未处理重塑土样和不同养护龄期(28、90 d)下的石灰改良土样,采用滤纸法测定不同温度(0~40℃)下各土样的土水特征曲线。结果表明:石灰改良、养护龄期和温度均影响土样的持水性能,并且这种影响会随含水率的下降而降低;温度效应随温度升高而减弱。最后,采用VG模型拟合土水特征曲线,并探讨石灰改良、养护龄期和温度对于VG模型各项参数a、n、θs、θr的影响。研究结果揭示了不同温度下(0~40℃)石灰改良黄土持水特性的变化规律,为不同环境下石灰改良土水力特性的预测以及工程设计参数的选取提供依据。

Lime treatment is an economical and useful soil improvement method.However,lime-treated soils in site always present a serious degradation in strength,since they are exposed to the long-term changes in climate and environment.Water retention curve is essential to study the pore water movement inside soils and their hydro-mechanical behavior.This paper investigates the influences of temperature and curing time on the water retention curve of lime-treated soil.In this test,untreated samples and lime-treated samples(28,90 d)were statically compacted.The water retention curves of untreated and lime-treated samples were measured at different temperatures(0~40℃).The results indicate that the water retention capacity of loess is effected by lime treatment,curing time and temperature changes.The effect decreased with the moisture content dropping.The temperature effect gradually weakens with the temperature increases.Besides,the VG model was applied to model the water retention curve of loess.And the effects of temperature and curing time on the parameters of a,n,θs,θr are analyzed.The research results can provide useful information for engineering construction.