Test Study on Speed-dynamic Characteristic of reinforced roadbed at bridge approach

Through dynamic test system, the speed-dynamic characteristic of a bridge-approach roadbed is studied in field test of a high speed railway, the dynamic stress influence characteristic of seamless track bridge-approach roadbed in line and depth is obtained under train´s running speed; at the same time, the conception of speed power coefficient is presented, and the speed power coefficient of bridge-approach roadbed is lesser than 0.3, and the existence of the critical speed which influence the roadbed dynamic characteristic is forecast. The research results provide some important instruction for the design and construction of bridge-approach structure of high speed railway.