不同齡期下石灰改良土持水特性的溫度效應(yīng)

靳奉雨 王葉嬌 孫德安 曾玲玲

摘要：石灰改良是一種經(jīng)濟(jì)、有效的土質(zhì)改良方法，在實(shí)際工程中，改良土由于長(zhǎng)期暴露在復(fù)雜氣候與環(huán)境中，普遍存在長(zhǎng)期強(qiáng)度衰減現(xiàn)象。土水特征曲線是研究土體水分運(yùn)移規(guī)律及其水力性能的重要途徑。為研究溫度和養(yǎng)護(hù)齡期對(duì)石灰改良土土水特征曲線的影響規(guī)律，制備了未處理重塑土樣和不同養(yǎng)護(hù)齡期（28、90 d）下的石灰改良土樣，采用濾紙法測(cè)定不同溫度（0～40 ℃）下各土樣的土水特征曲線。結(jié)果表明：石灰改良、養(yǎng)護(hù)齡期和溫度均影響土樣的持水性能，并且這種影響會(huì)隨含水率的下降而降低;溫度效應(yīng)隨溫度升高而減弱。最后，采用VG模型擬合土水特征曲線，并探討石灰改良、養(yǎng)護(hù)齡期和溫度對(duì)于VG模型各項(xiàng)參數(shù)a、n、θs、θr的影響。研究結(jié)果揭示了不同溫度下（0～40 ℃）石灰改良黃土持水特性的變化規(guī)律，為不同環(huán)境下石灰改良土水力特性的預(yù)測(cè)以及工程設(shè)計(jì)參數(shù)的選取提供依據(jù)。

關(guān)鍵詞：石灰改良土;持水特性;濾紙法;溫度效應(yīng);齡期

中圖分類號(hào)：TU444 文獻(xiàn)標(biāo)志碼：A 文章編號(hào)：20966717（2020）03002408

Abstract：

Lime treatment is an economical and useful soil improvement method. However， limetreated soils in site always present a serious degradation in strength， since they are exposed to the longterm changes in climate and environment. Water retention curve is essential to study the pore water movement inside soils and their hydromechanical behavior. This paper investigates the influences of temperature and curing time on the water retention curve of limetreated soil. In this test， untreated samples and limetreated samples（28， 90 d）were statically compacted. The water retention curves of untreated and limetreated 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.

Keywords：limetreated soil; water retention characteristic; filter paper method; temperature effect; curing time

中國(guó)西北黃土高原地區(qū)太陽(yáng)輻射強(qiáng)，夏季炎熱短促，冬季寒冷漫長(zhǎng)，晝夜溫差和季節(jié)性溫差較大，存在大面積的多年凍土和季節(jié)性凍土。當(dāng)溫度大幅變化時(shí)，土體會(huì)產(chǎn)生凍脹融沉，對(duì)該地區(qū)的巖土構(gòu)筑物造成一系列不容忽視的病害，如路基的不均勻沉降，嚴(yán)重影響道路的使用性能。為改良土體的工程性能，石灰被廣泛應(yīng)用于中國(guó)西北地區(qū)土質(zhì)改良工程[1]。……