Experimental Research On Dynamics Of Pavement Structure Model In Vehicle And Pavement System

With the increaseing of the traffic flows, the faster driving speed and the heavier vehicle axle load, the early damage of pavement is more and more serious. Therefore, the research on the dynamics behavior of pavement structure in the effect of the vehicle moving loads has become the key attention domains. Carrying out the actual pavement dynamic test not only require huge financial and material resources, but also the test is hard to do. While the model test is not only easy and convenient to be made in the laboratory, but also can reflect the prototype characteristics. So carrying out the dynamic experiment research of pavement structure model in vehicle and road system, so as to deeply understand the dynamic response of the pavement structure under moving loads has important economic significance and practical importance.Based on the existing conditions in the laboratory,the paper designed a1.5m-long steel beam model, a distribution stiffness pavement model supported by springs,a four-wheel car model which can provide simple harmonic excitation and a single degree-of-freedom quarter-car model.The bending stiffness, natural frequency and damping ratio of the steel beam have been tested.Through the modal experiment, the first seven order vibration mode,the modal frequency and modal damping of the steel beam model is gotten.The static load experiment verified that the simple supported beam was in good elastic state. Using formation decomposition method solved the dynamic response of the simply supported beam in the effect of mobile quality and mobile harmonic excitation and the dynamic response of the elastic supporting pavement in the action of mobile harmonic excitation and a single degree-of-freedom quarter car model respectively.Numerical calculation which is gotten by the use of the Newmark method is vertified by the model experiment. Finally, considering the pavement roughness function,the dynamic response of the pavement was studied through the experimental study under the impact action.The main research contents and conclusions are as follows:(1)Speed adjusting motor with mass block in the shaft end was fixed in the car model. Regulating the speed adjusting motor can realize different harmonic excitation frequency to the pavement. In a certain speed range, the higher the speed, the harmonic excitation effect of the pavement is more obvious.(2)Dynamic deflection curve for the simple supported beam in the effect of the mobile loads is a kind of sine wave. In a certain speed range, the impact coefficient of the simple supported beam is increasing with the moving load speed.(3)When using the model test researches the dynamic response of the pavement structure model in the vehicle and road system, the experiment which used uniform distribution spring to bear the pavement to simulate the continuous bearing pavement is viable and it could have gotten satisfactory experimental results.