Theoretical And Experimental Study On The Condition Of Space Axisymmetric For Torsional Wave Dynamic Testing Of Pile

The paper presents a study of propagation law of torsional wave in the condition of space axisymmetric and the method of experiments.Firstly, a 3D (axisymmetric) computing model for transient vibration of soil-pile system is presented based on elastic theory. Then the wave equation of torsional vibration is obtained and the numerical solution is worker out by finite difference method of staggered grid .Secondly,the dimensional reticle of integrate pile at dissimilarity time and the theories curve of the blemish pile of typical model is gained; the source of 3D effect initially is analyzed;in the meanwhile, the average velocity of torsional wave propagating in the pile is discussed. Finally, theory results are verified by model experiment. Meanwhile, the theoretical conclusions' correctness is proved by the comparison of theoretical calculation with field velocity curve.It is shown that the dimensional reticle reflectly the laws of torsional wave propagating in the pile; The pile radius, the duration of impulse,the material of pile,the dissimilarity position of sensor and shear velocity of the soil around the pile have influences on 3D effect. Meanwhile, the theoretical conclusions' correctness is proved by the comparison of theoretical calculation with field velocity curve.