非饱和膨胀土强度及土水特性室内试验研究

摘要

依托某浅埋膨胀土隧道工程,制备不同含水率的土样进行直剪试验,建立了膨胀土强度参数随含水率变化的经验公式,采用滤纸法测得膨胀土在吸湿过程中基质吸力随含水率的变化规律,并依据试验数据对土-水特征曲线按V-G模型进行拟合并确定拟合参数,结果表明:现场膨胀土属于低压缩性土,具有中等膨胀潜势,土体摩擦角随含水率的增加呈线性减小,黏聚力随含水率的增加呈二次抛物线形减小,土-水特征曲线与V-G模型拟合程度较好.%On the basis of a shallow-buried expansive soil tunnel,the direct shear test was conducted on the soil samples with different moisture content,and the empirical equations for the variation of strength parameters of expansive soil versus various moisture contents were evaluated.The variation of matric suction versus moisture contents during the moisture absorbing process was measured by filter paper method.Based on the test result,the Soil-Water Characteristic Curve(SWCC)was fitted and the parameters were determined by the V-G model.Test results show that the field expansive soil exhibits low compressive and medium expansibility.The friction angle decreased linearly,while the cohesion decreased quadratically with the increase of moisture content.The SWCC was in goodness of fit using the V-G model.