基于滤纸法的裂隙膨胀土土水特征曲线试验

Experimental study on SWCC of expansive soil with cracks using filter paper method

针对传统测量吸力试验方法存在的缺陷,采用滤纸法进行了裂隙膨胀土的吸力测定试验,得到了裂隙膨胀土的土水特征曲线,该曲线形态与无裂隙膨胀土的基本相同,均可分为3个阶段,为倒"S"形。相同含水率条件下,脱湿路径下制备的试样基质吸力比吸湿路径下的大,存在明显的滞回现象,可用已有的土水特征曲线计算模型进行拟合分析。试验结果表明,滤纸法可获得任意状态下土体的吸力,不干扰土体的初始状态,可作为测量裂隙膨胀土等特殊性土吸力的一种有效方法。

To overcome the shortage of traditional suction test methods,the filter paper method was applied to measure the matric suction of expansive soil with cracks and the corresponding soil water characteristic curve（SWCC） was obtained.The characteristics of expansive soil with cracks are found to be similar with the characteristics of the soil without cracks.The SWCC is composed of three parts and is shown as an inverted ‘S＇shape.Under the same water content conditions,the matric suction of expansive soil under the conditions of drying is greater than that under the condition of wetting.The drying and wetting curves form a hysteretic loop and a hysteretic phenomenon is clearly shown.The test results can be fitted and analyzed by existing calculation models of SWCC.It is revealed that the filter paper method can be used to obtain the soil suction under any status avoiding the interference to the soil original status.It is an effective method to measure the suction capacity of expansive soil with cracks and other special soils.