Remedial Method For Foundation Settlement Of CRTS Ⅰ Slab Track

The ballastless track for the high-speed railway has been widely used in the modern railway construction. As one of the important achievements, the CRTS I slab track system makes a great contribution. Due to the heavy passenger carrying capacity, the wheel-rail interaction is aggravated, which speeds up the failure of track components. The subgrade acting as a continuous and steady supporting foundation with uniform stiffness ensures the geometry of the upper track structure and bears the vehicle dynamic load. The normal operation condition is of great importance to ensure the safety of the high-speed railway operation.Aiming at the foundation settlement within a long and large section of the CRTS I slab track, the research work are listed as follows.(1) According to the main performance patterns of the foundation settlement, the dynamic analytical model for the vehicle-track-settling subgrade system was establishe to study its adverse influence on the vehicle operation. The maintenance standard on the foundation settlement is therefore proposed. The minimum maintenance curvature radius should be20000～35000m with the operation speed being200km/h～250km/h; the minimum radius of curvature of maintenance should be30000～45000m with operation speed being300km/h～350km/h.(2) As for the vehicle dynamic load induced re-settlement of subgrade, the settlement law is important for the treatment scheme implementation. The recognition and prediction methods for the foundation settlement has been discussed to provide the necessary theoretical support for the selection of reasonable maintenance time.(3) By comparing the existing maintenance methods, the maintenance methods aiming at the foundation settlement within a long and large section mainly include plate lifting, increasing the thickness of CA mortar layer and restoring the original rail surface geometry. The bagging method and the moulding method are compared, and the maintenance and construction technology process of the plate lifting method are analyzed and designed.(4) The construction by means of plate lifting is affected by the skylight time. The temporary support and slope treatment are required. Through the dynamic calculation analysis, the train speed should be limited at160km/h, and8blocks with the size of20cm X20cm should be uniformly inserted under the track slab for the temporary support. Under the condition of slope, the slope rate for each board should be limited to0.‰.(5) The quick-set cement mortar is adopted as the maintenance material. The strength within30minutes is about7MPa. The results show that the mortar stress is less than7MPa when trains pass through. Therefore, the maintained track length during one skylight time is mainly affected by the construction organization design and skylight time.(6) Based on the characteristics of the maintenance and construction for China high-speed railway, this paper discussed the matrix management mode from the operating view, and established specialized construction organization mode for high-speed railway maintenance. As for maintenance of roadbed settlement construction for long and big section, workflow analysis and maintenance quality control factors discussion based on Petri net are conducted in the end of this paper.