Through a series of tests such as filed plane loading test, static cone penetration test, standard penetration test, lateral pressure meter test, standard indoor consolidation test, triaxial compression test and field settlement observation that can get the deformation behavior of settlement on unsaturated subsoil between Qingdao and Jinan special passenger train.

The paper introduces reasons and features of saturated soil roadbed of collasible loess.

The seepage of unsaturated soil roadbed and the change of water content of the roadbed are studied with FDEM rainfall model.

The research shows that under the earthquake loading,the horizontal vibration acceleration of natural saturated sand foundation is amplified from underside to upside;the regularities of distribution of excess pore water press ra.