对膨胀土胀缩等级的分类是治理膨胀土的首要工作。基于可拓工程方法，选取自由膨胀率、膨胀总率、液限、塑性指数、<0.005 mm黏粒含量5项指标作为判别因子，为避免主观因素对确定评价指标权重的影响，提出熵值法计算物元模型中各评价指标的权系数的方法，建立了膨胀土胀缩等级判别的熵权可拓模型并应用于从襄荆高速公路沿线取回的部分土样的胀缩等级判别。实例应用表明：熵权可拓模型对膨胀土胀缩等级的判别结果合理，客观地反映了膨胀土判别的复杂状况，具有较高的可靠性和易操作的优点。

Classification of the shrink and expansion grades of expansive soils is an initial and essential work for engineering construction in expansive soil area. Based on the engineering methods of Extenics theory, five indexes, including free expansion rate, swell-shrink total ratio, the liquid limit, plastic index, and clay particles of less than 0.005 mm are selected as the factors for comprehensive  evaluation of expansive soil. To avoid the impact of subjectivity on weights allocation in traditional method of extenics evaluation index, the entropy theory is employed to calculate the weight aggregation of evaluating factors. An extenics model based on entropy weight is established and applied to the classification of expansive soil samples collected from Xiangyang-Jingzhou expressway. It is shown that the entropy matter-element model is highly reliable and easy-to-operate. The classification results are rational and objectively reflect the complexity of judging the shrink and expansion grades of expansive soils.