Research On Track Stiffness State Evaluation Technology Of Heavy-haul Railway Based On Track Loading Vehicle

Track stiffness is an important factor that affects the dynamic response of the structure and the track service state, and the result of the track deterioration as well. A large part of the maintenance work is the management of the track stiffness. Track state assessment techniques, based on the stiffness detection results, as an important part of corrective maintenance, are significant to the guidance of stiffness management and contradictions between the heavy maintenance workload and large transport capacity. This paper was based on the detection results of the track stiffness by the track loading vehicle and considered two aspects, vehicle-track coupling dynamics and evolution tendency under various gross tons. Completed works are as follows:(1)According to the test results, track stiffness distribution tendency of the subgrade, bridge and tunnel sections were analyzed and the approximate distribution fitting rules of each were developed.(2)Four typical sections of track stiffness irregularity, namely subgrade, tunnel, bridge and transition section and three cases- stiffness irregularity only, geometrical irregularity only and stiffness irregularity plus geometrical irregularity – were selected. Then, vehicle-track dynamic rules, characteristics and typical types of track stiffness irregularity were summarized.(3)Nonlinear rules of track dynamic irregularity were studied through dynamic simulations and the worst condition of track dynamic irregularity was found. In addition, effects on track state of track stiffness local mutation, sleeper hanging, transition sections and stiffness on weld joints were analyzed and recommendation values for the guidance of track stiffness mutation and length of the transition section and maintenance suggestions for different sections were finally given.(4)Based on the track stiffness test on Shuo-huang Railway heavy line by the track loading vehicle, the stiffness distribution of subgrade sections and bridge and tunnel rigid foundation sections was found, under conditions of different ballast cleaning years(gross tonnages). According to the developing characteristics of track stiffness of various lines, two evaluation indexes, track stiffness and the changing rate, were chosen and suggestion values for track stiffness management of different foundations was finally put forward.