Research On Tamping Mechanism Of Harden Railway Roadbed

With the increase of China’s railway mileage, conservation of railway is becoming increasingly onerous. Tamping is an important part of railway overhaul and routine maintenance, which aims to restore track geometry, increase the density and resiliency of ballast to ensure the safe of the train. Therefore, improving the efficiency and quality of tamping is very important.Small hydraulic tamping machine has a very prominent problem during the operation: due to the different quality and the compacted state of the roadbed, the compactness of the roadbed are quite different after maintenance, especially on the compacted roadbed.it is difficult to meet the requirements. At present, domestic and foreign researchers have conducted various studies on tampping, but the main object of study is tamping the clean roadbed,less to the harden roadbed. There is lots of mud and coal spreading outside, the harden roadbed is a widespread problem. Therefore, it is necessary to research the tamping on harden roadbed.The harden roadbed can be considered sprayed with glue, the ballast links to other, since the ballast has an adhesive force,when tamp the roadbed, we need to destruct the state of cohesion,so the ballast can be rearranged. Traditional test bench is difficult to simulate the interaction between harden roadbed, so this paper, we use the numerical simulation method to simulate the adhesion between the roadbed, by setting different sizes simulate different compaction state.First, this paper researches on the formation process of compaction and structural characteristics of the roadbed, analyzes the regularity of a small vibration hydraulic tamping machine. Then, established ballast particles and harden roadbed models based on three-dimensional Discrete Element Method software EDEM. Finally, import the tamping rod to simulate the whole process of tamping. This paper analyzes the main factors influencing the harden roadbed tamping, including the degree of compaction, the relationship between the height from the road, the frequency amplitude, frequency, etc.The results show that the degree of harden roadbed more severe, the larger the force of tamping rod, the harden roadbed is more difficult to destroy, the degree of compaction is lower;To different roadbed level, the best tamping frequency and amplitude is also different; To different roadbed state, tamping times is not the same, tamping times can be judged according to the change of force on the rod.