采用《公路工程地质勘察规范》(JTG C20—2011)推荐的自由膨胀率、塑性指数、标准吸湿含水率作为膨胀土判别与分类指标,将膨胀潜势分为非、弱、中等、强膨胀土4个等级。以某高速公路沿线土样为例,利用SPSS软件建立了土膨胀潜势分级的有序Logistic回归模型,并利用所建模型对待判土样进行判别,结果与实际一致。研究结果表明:有序Logistic回归模型的判别性能良,能客观反映膨胀土分类的复杂状况,具有较好的工程应用前景。

According to Code for highway engineering geological investigation (JTG C20—2011), three indices, namely, free expansion rate, plasticity index, and water content of soil under standard moisture absorption, were selected as the factors for synthetic evaluation of expansive soil. The swelling potential of expansive soil was divided into four grades: non-expansive, weakly expansive soil, moderately expansive, and strongly expansive. With the soil samples along a highway as an example, the ordinal Logistic regression model of swelling potential classification was established by using SPSS software and was applied to testing other cases. The predicted results were in good agreement with the actual. The results indicate that the ordinal Logistic regression model performs excellently, and can objectively reflect the complicated situation of expansive soil classification, thus is of good prospect in practical engineering.