Study On Compaction Dynamics And Key Technology Of Compaction Process Control Of Oscillatory Roller

Oscillatory roller is the compaction machinery which uses a novel thoughts and technology to realize vibratory compaction techniques. As vibratory roller excite compacted material particles to vibrate in vertical direction, oscillatory roller can also excite compacted material particles to vibrate in horizontal direction and makes rearrangement of material particles in a dense way with reducing the friction force between particle and particle.Based on establishing the interactive dynamics model of oscillatory drum and compacted material, the dynamic identification of parameters of dynamics model and some tests on the spot of a sample machine of oscillatory roller are studied, the amplitude-frequency characteristics of oscillatory roll is tried out and the compaction effect of between the oscillatory roller and the vibratory roller in the world are discussed. On the basis of an amount of tests on the spot, the parameters of dynamics model about oscillatory drum are optimized, main effect factors of the compaction degrees for oscillatory roller are analyzed, the optimization standard of evaluating compaction quality of road surface is advanced, the optimization control model of the unit effective compaction power and the target function of compaction process control on the basis of energy balance are established. Through analysis control tactics of intelligent compaction for current vibratory roller and oscillatory roller, based on energy balance, a new control tactics which the biggest effective compaction power absorbed by unit compacted material and the shortest time of whole compaction process is taken as the target of automatic or intelligent control compaction for oscillatory roller is put forward, its methods and ways for oscillatory roller to realize intelligent control compaction on the key technology are showed clearly.On the basis of above-mentioned research, the following conclusions are achieved:1 .On the spot, through an amount of tests of the main working factors (amplitude, frequency, speed, times of passes) effecting compaction effect of the vibratory/oscillatory roller, the test shows that to evaluate compaction effect and compaction quality need consider not only the average compaction degree of compacted layer, but also the even of the degree. Therefore, it is necessary for obtaining compaction quality to prevent less or more compaction.2. Based on above-mentioned study result, the optimization standard of evaluating compaction quality of road surface is advanced. That is, the vibratory energy transmitted by roller to pavement layer should balance with the effective compaction power absorbed by compacted materials during the whole compaction, so as to ensure the pavement layer to prevent less or more compaction. This conclusion is provided theory basis for further to establish the optimization target of intelligent compaction control.3. Under different excited energy (different nominal amplitude and excited frequency) and different times of passes (different stiffness and damp), through a lot of tests and analysis of the amplitude-frequency characteristics and the density-frequency characteristics, a series of important guidance results have been reached for formulating the optimization control tactics of intelligent compaction process, including:(1) For different nominal amplitude and different times of passes, between the amplitude-frequency characteristics and the density-frequency characteristics have a good related relationship which the frequency corresponding to the maximum amplitude and the maximum density is same on above two curves of the characteristics, and the charge of the two curves is similar. The above results show that it is feasible utilizing the amplitude-frequency characteristics to forecast the relationship of the compaction degree to change with the frequency.(2) Under different excited energy and different times of passes, the test demonstrates that it is very small for the charge range (27Hz～31Hz) of the best excited frequency corresponding to the maximum actual amplitude and the maximum compaction degree. This result points out the direction which searches for the best frequency during actual compaction process.(3) The simulation amplitude-frequency characteristics with computer and the actual amplitude-frequency characteristics by test show that the carve of amplitude-frequency characteristics has a rapidly fall low point when less than the frequency corresponding to the maximum amplitude, but when more than the frequency corresponding to the maximum amplitude, and the carve changes gently. These show that selecting the best frequency should be more than a little the frequency corresponding to the maximum amplitude so as not to slip the low point owing to accidental factors. This result provides basis for determining the initial value in optimization control.4. In one times of pass, the influence factors of compaction quality of pavement layer are excited amplitude, frequency and speed of pass. On the basis of research the interactive relationships of above three factors, the calculation formula of the effective compaction power absorbed by unit length pavement layer and the energy balance equation as well as its unit compaction power and energy balance equation in more times of passes are achieved, which will lay the theoretical foundation for establishing the optimization target function on the basis of energy balance. 5. The evaluating standard of energy balance on the bases of analyzing interactive relationships of between slip-rotation ratios, excited energy and effective compaction power advanced. the method of real measuring the slip-rotation ratio and determining the best slip-rotation ratio during actual compaction is put forward, which will provide means for evaluating the energy balance whether or not to be fulfilled requirements.6. Based on above theory and test, to study the key technology of oscillatory compaction process have acquired some important results which establish the optimization target of intelligent control on the basis of energy balance and its corresponding to the target functions, draw up the control tactics for the optimization target to realize, and design the automatically control flow chart for the intelligent controller. Above the key technologies solved will lay the solid foundation for intelligent compaction control system of oscillatory roller to be studied.The studies make great progress in the dynamics process of oscillatory drum and compacted material, as well as intelligent control compaction for oscillatory roller. The conclusions are significant in both research and application of domestic traditional roller and intelligent oscillatory roller.