Search And Exploitation Of Double-Acting Hydraulic Pile Hammer With Double Cylinders

Hydraulic pile hammer is one of the pile driving machines that drive prefabricated piles into the ground in the construction of pile foundation such as construction,bridge,dock, etc.With the development of science and technology ,the prefabricated pile driving machines evolve from block hammer ,steam-hammer ,diesel hammer to hydraulic hammer .Hydraulic pile hammer is one of ideal prefabricated pile driving machines because it can adjust stress waveform ,decrease stress peak value,prolong effectual action when it drives piles .Hydraulic pile hammer is used widely and formed series in developed countries now. Mechanical impact dynamics is used to analyse the production and spread of stress wave when hydraulic pile hammer hammerblows piles, the stress wave influence the course of driving pile.Slender hammer that is equal to wave resistance of the pile can bring ideal stress waveform.When the hammer weight is constant, efficiency of driving pile can be increased by means of selecting drive cap and cushion pad of different rigidity to match the hammer according to various geological condition and the pile.The structure and principium of hydraulic system of double-acting hydraulic pile hammer with double cylinders is studied in detail in the paper,the hydraulic system and electric control system of six-ton-double-actin hydraulic pile hammer with double cylinder is designed on the basis of it. Power bond graph is used to established the bond graph model of the lifting and dropping of hydraulic pile hammer and state space equation in the paper for hydraulic pile hammer is perplexing nonlinear system.In order to attain the graph that pressure, position, velocity, acceleration vary with time in the course of driving pile simulation procedure solving state space equation is designed on the basis of combining four-order Runge-Kutta method with predicator-corrector method,dynamic simulation of the hydraulic system is studied in MATLAB 6.5.It is convenient to analyse dynamic characteristics of the hydraulic system,beneficial to the design and parameter optimization of the hydraulic system.In the final part of the paper, under detailed analysis of the control characteristics for double-acting hydraulic pile hammer with double cylinders, control system based on the programmable logic controllers founded on technology of modern compute is designed. PLC has small cubage,strong function,high reliability, ability to adapt abominable field environment of construct machine to face.In order to improve adaptive ability of hydraulic pile hammer to various soil, various finial velocity and dropping length must be obtained by adjusting time of lifting,dropping and keepingpressure that is accurately selected by the control system of PLC .