中文摘要：

通过控制恒温恒湿箱的温湿度工作参数,实现饱和膨胀土在不同脱湿速率条件下的状态变化,借助收缩试验和非饱和三轴试验,研究脱湿速率对膨胀土收缩特性、强度特性与持水特性的影响规律。试验结果表明,膨胀土的收缩系数随脱湿速率的减小而变大,并先呈现线性脱湿过程,后呈现非线性脱湿特征;在相同含水率条件下,膨胀土的吸附强度亦随脱湿速率的减小而增大,尤在含水率和围压较低时更趋明显。结合吸附强度与吸力关系的乘幂函数表达式,利用收缩系数和吸附强度反算出不同脱湿速率下的膨胀土“双线性”土水特征曲线,发现不同脱湿速率时曲线下降段接近平行趋势,脱湿速率越小,膨胀土的进气值越大,相同含水率时的吸力越高。

英文摘要：

Through adjusting the working parameters of temperature and humidity in the constant temperature and humidity equipments, the state variation of saturated expansive soil under different drying rates is achieved. The influences of the drying rates on shrinkage, strength and water retention characteristics of expensive soil are investigated, in which the shrinkage tests and the unsaturated triaxial tests are employed. The experimental results indicate that the coefficient of shrinkage increases as the drying rate decreases, and that the drying process is linear at the beginning and then becomes nonlinear. Moreover, the suction strength of unsaturated expansive soil increases as the drying rate decreases under the same water content, which is more prominent especially under the condition of low moisture content and confined pressure. Based on the expression of power function relationship between suction strength and suction, a bi-linear water retention curve is back-calculated from the coefficient of shrinkage and suction strength. It is found that the drop part of water retention characteristic curve tends to approximate parallel under various drying rates. The smaller the drying rates, the greater the air-entry value and suction.