The characteristics of dynamic stress in foundation soil cause by train load

摘要

Train-induced settlement is of great concern and in this sense the dynamic stress in the foundation soil caused by train loading becomes a research hotspot. This paper investigates the relationship between the train-induced dynamic stress and the loading form. Both the dynamic stresses on the top of the embankment and inside the ground are considered. Study results reveal that the dynamic stress on the ground surface increases highly with the velocity. Dynamic stresses calculated by the equivalent static load method and velocity coefficient method differ from each other in the shallow part of the ground. The train-induced dynamic stress in the ground also increases with the load velocity. Different forms of load distribution have a big influence on dynamic stress. For the soil at the same depth, the dynamic stresses under strip load are bigger than that under moving square load. However the dynamic stress caused by strip load can be ignored when the load velocity lower than 0.6 times of the shear wave velocity. Study results show that for practical use the velocity coefficient method is recommended for calculating stresses on the ground surface and the dynamic stress caused by the load velocity in ground soil can be ignored.