【作者】 龚壁卫； 包承纲； 吴宏伟； 王斌；

【Author】 Gong Biwei;Bao Chenggang;Wu Hongwei;Wang Bin Yangtze River Scientific Research Enstitute,Wuhan 430019 China HongKong University of science and Technology China

【机构】 长江科学院土工所； 香港科技大学土木及结构工程系；

【摘要】 自然界中的土,通常是以土粒、土中水和土中气三相形式存在,也即是常说的非饱和土。非饱和土的研究,不可避免地要涉及到土中气、水存在形态以及相互转换规律。将非饱和土的水气转换的细观现象与土的特性联系起来,才能定量的描述非饱和土强度、变形等规律。为此,本文作者进行了非饱和膨胀土的有关试验研究,重点探讨了非饱和膨胀土的水气运动规律,分析比较了膨胀土在反复干湿循环条件下的土木特征曲线,以及原状膨胀土与重塑膨胀土试样在相同实验条件下的土水特征曲线等。对于应力状态对非饱和土水气运动规律的影响,本文也进行了初步探讨。更多还原

【Abstract】 In this paper,the drying and wetting soil-water characteristics of some intact and recompacted expansive soil specimens obtainedfrom Hubei and Henan, China, have been investigated using some conventional volumetric pressure plate/membrane extractors together with anewly modified triaxial cell, in which the air pressure and pore water pressure and backpressure can be controlled. Comparisons have beenmade between the soil-water characteristics obtained by using the conentional and the new measuring devices, and comparisons between thediffierent initial water content, and SWCC with three cycles of the expansive soil. It is found that the air-entry value of an intact sample is sub-stantially smaller than that of a recompacted sample with the same initial dry density and water content.The measured low air-entry value maybe due to the existence of some fissures in the natural sample. Moreover, the rate of desaturation is smaller for the natural intact specimen thanthat for the recompacted soil. The hysteresis is an interesting phenomon in the investion on SWCCs. The marked hysteresis can be seen betweenthe drying and wetting curves. For the natural intact specimens,the first hysteresis loop is larger than the second one.更多还原