Theoretical Study On Space Three-dimensional Problem For Low Strain Dynamic Testing Of Pile

A pile is space three-dimensional(3D) object in engineering practice, the material property and the deficiency of pile, the property of soil and the location of impulse are incompletely axisymmetric. In order to simulate the situation of dynamic testing better and provide more dependable theoretical basis for the explanation of testing results, the 3D calculation modeling of transient vibration of pile-soil system is set up in 3D coordinate. The numerical solution of vibration of pile-soil system is worker out by finite difference method of staggered grid and 3D simulative forward modeling computation for dynamic testing of pile can be carried out by using this method. Through computation and analysis, the effects on longitudinal dynamic response on the top of nonaxisymmetric necking pile, which caused by the depth and the extent of nonaxisymmetric necking deficiency, the location of impulse and pile's length, is discussed, and provide relevant suggestions for dynamic testing. Meanwhile, the theoretical conclusions' correctness is proved by the comparison of theoretical calculation with field velocity curve.