岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
7期
1839-1846
,共8页
土-水特征曲线%压力板法%滤纸法%蒸汽平衡法%全吸力范围
土-水特徵麯線%壓力闆法%濾紙法%蒸汽平衡法%全吸力範圍
토-수특정곡선%압력판법%려지법%증기평형법%전흡력범위
soil-water characteristic curve(SWCC)%pressure plate method%filter paper method%vapor equilibrium method%full suction range
膨胀土的失水收缩、吸水膨胀过程分别对应着土-水特征曲线的脱湿和吸湿阶段。土-水特征曲线对于研究非饱和土的水力与力学特性有着重要作用。用压力板法（吸力范围0～1.5 MPa）、滤纸法（吸力范围0～40 MPa）和蒸汽平衡法（吸力范围3～368 MPa），分别对南阳膨胀土进行了土-水特性试验，得到全吸力范围内的土-水特征曲线。试验结果表明：初始孔隙比大致相同土样的土-水特征曲线，在低吸力范围内脱湿曲线与吸湿曲线具有明显的滞回现象。当吸力大于300 MPa时，土-水特征曲线的滞回效应基本消失，即脱湿曲线与吸湿曲线基本重合。滤纸法所测出的土-水特性落在主脱湿和主吸湿曲线的滞回圈内。当吸力等于367.54 MPa时，含水率仅为0.325%，几乎近于0。孔隙比随着吸力的变化规律中，不仅受到吸力大小的影响，还受到吸力历史和吸力路径影响；孔隙比与吸力关系中，相同吸力时吸湿路径的孔隙比要比脱湿路径的大；在吸力低范围，吸湿路径与脱湿路径的孔隙比相近。孔隙比与饱和度关系因吸力路径的不同也存在着明显的滞回效应，接近饱和时趋近一致。变吸力情况条件下，饱和度随着孔隙比的增加而增加，蒸汽平衡法得出的孔隙比与饱和度的关系具有明显的线性关系，而压力板法做出来的低吸力范围内的线性关系不明显。
膨脹土的失水收縮、吸水膨脹過程分彆對應著土-水特徵麯線的脫濕和吸濕階段。土-水特徵麯線對于研究非飽和土的水力與力學特性有著重要作用。用壓力闆法（吸力範圍0～1.5 MPa）、濾紙法（吸力範圍0～40 MPa）和蒸汽平衡法（吸力範圍3～368 MPa），分彆對南暘膨脹土進行瞭土-水特性試驗，得到全吸力範圍內的土-水特徵麯線。試驗結果錶明：初始孔隙比大緻相同土樣的土-水特徵麯線，在低吸力範圍內脫濕麯線與吸濕麯線具有明顯的滯迴現象。噹吸力大于300 MPa時，土-水特徵麯線的滯迴效應基本消失，即脫濕麯線與吸濕麯線基本重閤。濾紙法所測齣的土-水特性落在主脫濕和主吸濕麯線的滯迴圈內。噹吸力等于367.54 MPa時，含水率僅為0.325%，幾乎近于0。孔隙比隨著吸力的變化規律中，不僅受到吸力大小的影響，還受到吸力歷史和吸力路徑影響；孔隙比與吸力關繫中，相同吸力時吸濕路徑的孔隙比要比脫濕路徑的大；在吸力低範圍，吸濕路徑與脫濕路徑的孔隙比相近。孔隙比與飽和度關繫因吸力路徑的不同也存在著明顯的滯迴效應，接近飽和時趨近一緻。變吸力情況條件下，飽和度隨著孔隙比的增加而增加，蒸汽平衡法得齣的孔隙比與飽和度的關繫具有明顯的線性關繫，而壓力闆法做齣來的低吸力範圍內的線性關繫不明顯。
팽창토적실수수축、흡수팽창과정분별대응착토-수특정곡선적탈습화흡습계단。토-수특정곡선대우연구비포화토적수력여역학특성유착중요작용。용압력판법（흡력범위0～1.5 MPa）、려지법（흡력범위0～40 MPa）화증기평형법（흡력범위3～368 MPa），분별대남양팽창토진행료토-수특성시험，득도전흡력범위내적토-수특정곡선。시험결과표명：초시공극비대치상동토양적토-수특정곡선，재저흡력범위내탈습곡선여흡습곡선구유명현적체회현상。당흡력대우300 MPa시，토-수특정곡선적체회효응기본소실，즉탈습곡선여흡습곡선기본중합。려지법소측출적토-수특성락재주탈습화주흡습곡선적체회권내。당흡력등우367.54 MPa시，함수솔부위0.325%，궤호근우0。공극비수착흡력적변화규률중，불부수도흡력대소적영향，환수도흡력역사화흡력로경영향；공극비여흡력관계중，상동흡력시흡습로경적공극비요비탈습로경적대；재흡력저범위，흡습로경여탈습로경적공극비상근。공극비여포화도관계인흡력로경적불동야존재착명현적체회효응，접근포화시추근일치。변흡력정황조건하，포화도수착공극비적증가이증가，증기평형법득출적공극비여포화도적관계구유명현적선성관계，이압력판법주출래적저흡력범위내적선성관계불명현。
The processes of dehydration shrinkage and water-swelling of expansive soil correspond to the drying and wetting stages of the soil-water characteristic curve (SWCC). The SWCC plays an important role in defining the hydro-mechanical behavior of unsaturated soils. In order to study the SWCC of Nanyang expansive soil in full suction range, three suction control or measurement methods are used: the pressure plate method for low suction range of 0-1.5 MPa, the filter paper method for suction range of 0-40 MPa, and the vapor equilibrium technique for high suction range of 3-368 MPa. The results show that the SWCC has obvious hysteresis phenomenon during the drying and wetting in the low suction range. When the suction is greater than 300 MPa, the hysteresis effect of SWCC disappears; and the drying and wetting curves are almost overlapped. Test data of soil-water characteristic by the filter paper method are located between the main drying and wetting curves of the SWCC. When the suction of is 367.54 MPa, the soil water content is only 0.325%, and it almost approximates to zero. Void ratio not only changes with suction, but also it is influenced by the suction history and suction path. In the relation between void ratio and suction, the curve of wetting path is above that of the drying path; and they become the same at low suction. There is a clear hysteresis of the relation between void ratio and saturation degree, due to the different suction paths; and they will be consistent when close to saturation. The saturation degree increases with the increasing void ratio when suction changes. The experimental data obtained by the vapor equilibrium method have an obvious linear relationship between void ratio and saturation degree; while the test data obtained by the pressure plate method are no an obvious linear relationship in the low suction range.
