两种快速测定非饱和土水力学参数方法的对比分析

Comparison between two methods for quickly determining hydraulic parameters of unsaturated soils

非饱和土水力学参数包括土-水特征曲线和渗透函数是非饱和土研究的重要内容。鉴于传统的测试方法耗时较长,提出了能够快速测定非饱和土水力学参数的一步流动方法和动态多步流动方法,并利用联合测试系统分别开展流动试验。通过对比分析,这两种方法得到的试样平衡态土-水特征曲线均与实测值接近,并且有效地避免了由于测试时间较长高压气体通过水流在陶土板背面析出的问题。一步流动方法比动态多步流动方法需要的时间短,但反算得到的土-水特征曲线与实测值的接近程度不如动态多步流动方法,因此,动态多步流动方法要优于一步流动方法。

The hydraulic parameters of unsaturated soils,including soil-water characteristic curve and permeability function,are very important to unsaturated soils.Because the traditional test method is time-consuming,one-step outflow method and dynamic multistep outflow method are proposed to get hydraulic parameters of unsaturated soils quickly;and the combined testing system is adopted to carry out the two flow tests.The results show that the differences of soil-water characteristic curves between the estimated and measured ones are small.The two methods also can avoid the problem of high-pressure gas through the water leaking in the back of the ceramic plate.The time of the one-step outflow method is shorter,but its accuracy is worse.So the dynamic multistep outflow method is superior to the one-step outflow method.