Optimization And Effect Evaluation Of Ballasted Track Precise Tamping Scheme Based On Track Smoothness

High-speed railway and speed-up operation railway have strict requirements on track smoothness.Ensuring good track smoothness is the foundation and key to safe railway operation.In recent years,large-scale maintenance machinery has been widely used for precise maintenance to improve the condition of ballasted tracks.However,large machines are susceptible to factors such as ballast compactness,vertical-lateral adjustment ratio,and hard rail bending.The tamping effect is difficult to achieve the expected effect,especially the control effect of medium and long wave irregularities is still insufficient.It is often necessary to increase the number of operations to reach the expected value.The tamping efficiency is difficult to match the limited time,and the tamping effect is difficult to meet the requirements of high smoothness and reliability of the track geometry state.Therefore,the development of a smoothness-based precise-tamping optimization plan and analysis of its impact on track irregularities are of great significance for further exerting the effect of maintenance on the improvement of track quality.The main work and results of this paper are as follows:(1)Explore the operating principle and operation method of the tamping machine.Analyze the residual deviations generated in different detection modes,and it is clear that the precision method can be used to eliminate its impact.Summarize in detail the specific operation content of track data precision measurement,large-machine tamping,dynamic stability,ballasting,dynamic and static testing.After sorting out the five-tamping threestable maintenance and repairing operation process,it lays the application foundation for subsequent research.(2)Combining the dynamics theory to study the medium and long wave comfort management standards suitable for controlling the state of the track.Based on this standard,the mathematical relationship between the track adjustment amount and the track smoothness index is constructed,and the theory of precise adjustment optimization is studied.The research results show that:(1)The management value of 60m/10 mm can effectively control the track irregularities in long and medium waves;(2)The precise tamping adjustment optimization algorithm has a stronger control effect on 60 m irregularities than traditional optimization methods,and can make the amplitude of lateral and vertical irregularities in the 100 m wavelength range smoother;(3)In the section where the optimization algorithm is used to implement the operation,the irregularity of 300 m is reduced by 30% to 40% compared with that before the precise tamping,and the improvement effect of the smoothness is much higher than that of the section where the optimization algorithm is not used to guide the operation.(3)Exploring the effect of tamping operation on the track quality index TQI from the perspective of mathematical characteristics.Analyze the influence of objective factors such as large-machine operating conditions,track characteristics,equipment accuracy,etc.on the smoothness of the track.Based on the theory of precise tamping adjustment optimization,the comprehensive control algorithm of track smoothness adapted to the operating characteristics of large machines is studied.The research results show that:(1)The largemachine tamping can effectively eliminate the horizontal,twisted,and longitudinal irregularities,but the ability to control the lateral irregularities is weak;(2)Traditional adjustment schemes lack sufficient consideration of factors such as the range of a single adjustment amount,the adjustment amount change rate,and the accuracy of the equipment,which can easily cause the adjustment amount of the plan to be unachievable;(3)Various factors affecting the operation effect of the large-machine are incorporated into the optimization model of precise tamping adjustment based on medium and long wave smoothness as constraints,forming a comprehensive control algorithm for track smoothness,and having the adjustment ability to adapt to the operating characteristics of the largemachine.It can effectively control the track irregularity.(4)The comprehensive control algorithm for track smoothness proposed in this paper was used to formulate a precise tamping plan,which was implemented in a maintenance project of a ballasted high-speed railway in my country.Evaluate the effect of fine-pounding operations in terms of time domain and frequency domain.The research results show that:(1)The wavelet energy method and the adjustment amount evaluation graph method can fully excavate the track irregularity change law in different operation stages,and reflect the actual state of the realization rate of the precise adjustment amount;(2)The overall TQI of the implementation section of the comprehensive operation of precise tamping was improved by 53.0%,of which,the lateral irregularity was improved by 21.0%,and the vertical irregularity was improved by 72.7%,which can effectively control the smoothness of the ballasted high-speed railway track;(3)The improvement effect of longitudinal irregularity is better than that of lateral irregularity.The irregularity of specific wavelengths such as 30 m and 60 m is eliminated,and the energy of longitudinal irregularity decreases significantly in a linear trend in the whole waveband;(4)The 30 m lateral and vertical irregularities have the strongest correlation with the TQI improvement rate.Taking 30 m irregularities as the main basis to guide the tamping decision-making plan is beneficial to improve the control effect of tamping operations on track irregularities.