The Studying On The Matching Of Pile And Hammer During The Low Strain Reflection Wave Method Test

Low strain dynamic-test pile technique has virtue of short period, low expense and distinct test effect, so it is now more and more noticed and welcomed by civil engineer, it's fact meaning and foreground is went without saying. At present, the inside and outside of the country lack the quantitative research on the relationships between Reflective wave's hammer property and stimulating impulse, lack pertinency of choosing hammer, lack in-depth analysis and calculate of low strain pile tip shallow. Judge the test result on comparing estimate experience and other test ways effects the experiment precise.This report in theory bases unit pulse load way from Prof Xiao dong tong of South east university and researching ways of matching hammer with pile from Prof Cheng Jiuzhao of Guangdong architecture and science academe as the finite element simulation, systemic analyses the relationships between each part of the hammer with stimulating pulse, analyses the quantitative relationships between the pulse width of vibration source and the hammer parameters(elastics module, rigidity, contact area and mass, etc), at the same time, it analyses any points' response to pulse in the pile tip and shallow part by using three-direction finite element, analyses the relationships between the source of stimulating vibration with pile shallow flaw.This report mainly uses finite element analysis program ANSYS10.0-/LS-DYNA to stimulate the vibration process of instantaneous bump between low strain pile and hammer in order that get any point in shallow part response parameters(including particle vibration displacement, vibration speed, vibration acceleration) of full big diameter concrete irrigation, hold reflective wave curve property. From changing the property of stimulation vibration source(change hammer material that is the different density, modulus of elasticity, and Poisson's ratio under the same volume), it analyses the hammer parameters'(including modulus of elasticity, impact area, material width, main piston frequency width) effect on low strain test pile precise. At last, it bases comparing real engineering example of changing vibration source from groundwork part of Guangdong architecture and science academe to design a series of standard hammer, in order to improve engineer test precise.