A Study Of The Mechanics Character Of Slab-track And Train Bodywork System On Soil Roadbed Under The Condition Of Track Irregularity

Ballastless track, which is widely employed in tunnels, on bridges and elevated structures, has been recognized universally by railway sectors all over the world. Soil roadbed is of low carrying capacity, and sensitive to dynamic load and water-etching; metamorphose and sedimentation of soil roadbed is difficult to control, so the application of ballastless track on soil roadbed is very limited. Hence it's very necessary and urgent to study the mechanics character and metamorphose of soil roadbed ballastless track and train bodywork caused by roadbed sedimentation and track irregularity.In this dissertation, soil roadbed-slab-track and train bodywork under the condition of track irregularity is taken as the object of study.Then,a whole train motion model is set up first; the train motion formula is solved by the means of MATLAB programming with Newmark approach employed, the effect harmonic track irregularity at different wave-depths on the train vertical vibration acceleration is calculated. Taking Japanese Shinkansen track irregularity management standards and the management standards of the degree of comfort under track irregularity as reference, corresponding indexes of the track irregularity are put forward. Focusing on paving slab-track on soil roadbed, using finite element analysis software ANSYS, a non-linear mechanical model of soil roadbed-slab-track system is established. In order to reflect the actual stress and deformation characteristic, entity-units are employed in this model, which means all structures are simulated at their actual size. The effect of 3 different wave-depths harmonic irregularity to the system under the condition of dynamic load is analyzed. The vertical displacement, vertical vibration acceleration, stress state of the central part and the end part of slab track panel, CA mortar, concrete seat are also analyzed. From the result, the following could be concluded: Among the 3 different wave-depths harmonic irregularity condition, the discrepancy of the displacement of board track, CA mortar, concrete base and bed-surface is minor. The maximum structure settlement can't go beyond the adjustability of the slab track. With the increasing of wave-depth, respective maximum horizontal, vertical and longitudinal stress show trends of dramatic increase, but still less than the design value largely.No tensile stress emerged in the surface layer and bottom layer of the roadbed, which is in line with the properties of surface layer material.Displacement and maximum stresses are mainly emerged between the two wheels of the train body, sometimes at the moment of the arrival of the front wheel or the leave of the back wheel.Track board counter-bending area is emerged in both vertical and longitudinal, which means the upper and bottom surface of track board can be possibly under tension or compression.Final by calculating and analyzing the effect of the increasing roadbed stiffness to all parts of the system, it's showed that: improving roadbed Stiffness conditions played a very obvious impact on reducing vertical deformation of the slab-track system on soil roadbed, and that would save more adjustable space for slab-track.At the same time, increasing roadbed stiffness has an ideal effect on bettering the stress of track board, CA mortar and the end of concrete base, especially on improving longitudinal stress, which will make full use of buffering effect of CA mortar and the great compressive property of concrete.