Analysis Of Influence Of Parameters On Low Strain Reflection Wave Method

Using the finite element program ANSYS/LS-DYNA, this paper simulated the influences of the parameters of pile-soil vibration system on the time-velocity domain curve of reflection wave and studied the reflected wave curve characteristics of the integrate pile with the change of the pulse width of exciting force, the diameter of the pile and the elastic modulus of pile. As to defective foundation pile, I analyzed the wave feature of the depth of defect, the degree of defect ,the length of defect, segeration, continuous variable sections, eccentric flaws and fractured pile. By means of comparing with the reflected wave curve of the integrate pile, the wave shape characteristics of segeration and loose pile top were drawn. As to the time delaying and dimension effect of shallow defective foundation pile, curve characteristics received at different points on the top of the pile were drawn. To study the problem of high frequency disturbance, I analyzed the wave feature at different received points. To study the curve characteristics of shallow severe defects, I distinguished the multi-defective pile from the same defect interface. As to the continuous variable sections, this dissertation studied the defect which was easy to misjudge. At last this dissertation provided the practical suggestion benefit to dynamic inspection to identify the shallow and deep tiny defect.