Study On Influence Of Exploiting Groundwater On The Settlement Of Pile-slab Embankment For Ballastless Track And Running Safety Of High-speed Railway

It becomes increasingly rampant to pump groundwater around high-speed railway lines out of agricultural or industrial demand. However, over-exploitation of will result in consolidation and settlement of the foundation soil, which is bound to aggravate the deformation of the embankement for high-speed railway line, then lead to track irregularity and unfavorable wheel-rail interaction. The running safety of the vehicles may be affected in some severe cases. Base on thorough investigation on previous research, in this paper, the typical pile-slab embankment is selected, and a fluid-solid coupling model and a dynamic coupling model are established to study the influence of pumping groundwater on track irregularity and dynamic responses of vehicle, track and pile-slab embankment. The main research contents are shown as follows:(1) The deformation laws of track and pile-slab embankment under the condition of punmping groundwater are studied. In the computational results, the lateral and vertical displacement of each layer of track and embankment all shows the characteristic of ’large in the middle, small on two sides’. Due to the action of vertical support and reinforcement of piles, the vertical displacement of track above pile top is larger than that above the bearing slab.(2) The influence of different embankment type, pumping rate and pumping distance on the deformation of track and embankment are contrastively analysed. In the computational results, pumping rate and pumping distance are both of great influences on the deformation of track and pile-slab embankment. Compared with non-reinforced embankment, the pile-slab embankment has obvious advantages in resisting lateral and vertical deformation, this is because the rigid of pile-slab structure are relatively large and the piles are embedded into the bedrock.(3) When the pumping distance is3000m3/d and pumping rate is200m, the dynamic responses of vehicle, track and pile-slab embankment under different axle load and speed of vehicle are studied. The results indicate that vehicles of different axle load and speed can safely pass through the groundwater exploitation area, and the increase of axle load will make driving safer and more stable.(4) The influence of track irregularity induced by different pumping rate and pumping distance on the dynamic responses of vehicle, track and pile-slab embankment are contrastively analysed. The results indicate that pumping rate has a great influence on running safety of vehicle, when the pumping distance is50m, the running security and stability of vehicle can not be guaranteed. When the pumping distance is200m, the influence of different pumping rate is not very obvious, this is because the track irregularity induced by different pumping rate is relatively smaller than the actual track irregularity.