Study On Hammering Performance Of Double-process Hydraulic Hammer

Abstract:Fully understandings of the the drivability of piles are very important in the design and construction phases of civil engineering, because it has a direct influence on the progress and cost of projects. Thus, it is of great significance to carry on studies on the drivability of piles. Due to their high efficiency, less pollution and good robustness, double-process hydraulic hammers have a wide application. So, focused on the above necessity and shortcomes, the drivability of piles by the double-process hydraulic hammer is studied. The main results are as follows:1. The background and origin of project and the application status of technique of pile-sinking by hydraulic hammers is firstly introduced. The introduction mainly focused on the research status, development significance of the studies on drivability of piles.2. The kinematics of double-process hydraulic hammer during its downstream stage is analyzed, and a mathematical model of hammer velocity is established; by comparing the models of hammer system at home and abroad, the dynamic model of the impact force of hammer is established combining the hammer velocity, and a model for the impact force of double-process hydraulic hammer is established, the factors on the impact force are analyzed.3. The resistance model of soil around piles is modified based on the geological characteristics and load transfer theory. By using the iteration model between displacement and load of pile tip, the mathmatical model for pile sinking resistance is established. A criterion for the drivability of piles suck by double-process hydraulic hammer is proposed based on the pile sinking mechanism of hydraulic hammer.4. Based on the established model and the proposed criterion, the effects of velocity, impact force and geological characteristics on the drivability of pile are studied by using MATLAB. The effect of hydraulic hammer, pile and soil on the drivability of piles are discussed.5. Experiments of pile-sinking by hammer are conducted. The results show that the presented method can be applied to predict the drivability of piles.