中文摘要：

以某高速铁路地基中微弱膨胀性泥岩为研究对象，结合无砟轨道高速铁路对变形要求极为严格的特点，用等效蒙脱石含量、阳离子交换量、自由膨胀率和液限4项指标作为模型因子，采用主成份分析法得出针对无砟轨道高速铁路的膨胀土判别式，通过无上拱处泥岩与膨胀力试验进行验证。研究结果表明：该判别式能够准确判别区分出对无砟轨道高速铁路有影响的膨胀土，且不会对更为微弱的膨胀土产生误判，并定量地判断泥岩的膨胀性强弱。可为无砟轨道高速铁路的地基膨胀土判别提供参考。

英文摘要：

This article mainly talks about expansive mudstone of high speed railway foundation in a Railway,andcombines with the characteristic of its strict requirements about displacement.There are4indexes which wereselected as model factors to establish mathematical model of discrimination of high speed railway throughprincipal component analysis and the model is validated by the expansion force.The results show that the modelcan accurately distinguish the expansive soil in the foundation and predict the swelling properties of mudstone.