Abstract:By in-situ dynamic test on expansive soil section in different rigidity embankments along Hefei—Nanjing rapid railway,the engineering characters of the different rigidity embankments were studied under the simulated train dynamic loads. It is verified that (1) the variations of dynamic stress of the embankments with different rigidities are the same,and the test values are close to the computed ones,(2) the elastic deformations of the embankments with different rigidities are 0.32 and 0.29 mm respectively,(3) road bedding coefficient can be significantly decreased after the graded broken stones are saturated,and the dynamic rigidity coefficient of the embankment is about 317 and 220 MPa/m after storm,and (4) the plastic deformation of the embankments with different rigidities increases rapidly at the beginning of the dynamic loadings. After the vibration times of 15 million,the plastic deformations are 0.9 and 1.1 mm respectively,which are mainly caused by the graded broken stones,and the improved soil nearly has no plastic deformation.