The field tests of dynamic stress and vibration response were conducted at Lianyan expressway with low embankment. The additional dynamic stresses and vibration displacement in roadbed were analyzed. In addition, in laboratory tests using dynamic triaxial test machine with stress controlled, definite dynamic stress frequency and different cyclic stress ratio were adopted to simulate the traffic load, and the axial strain, pore water pressure and axial strain softening under cyclic load were studied. The results show that the dynamic stress and vibration displacement increase with the increase of traffic velocity and weight, and decrease as the depth increases, the effective influence depth being about 2.5 m. Critical cyclic stress ratio of undisturbed soil is bigger than disturbed one. Dynamic shear strain of undisturbed soil exceeds that of disturbed one. Therefore, the strength of shallow subgrade needs to be reinforced and the disturbance of the subsoil during construction needs to be reduced. The result is useful for designing and constructing expressway with low embankment on soft clay.
Journal of Southeast University(Natural Science Edition)
dynamic triaxial test
cyclic stress ratio