Study On The Subgrade Disease Test And Strengthening Technology Baotou-Xi’an Railway

Because of the long-term operation, maintenance and repair and the long-term effects of nature environment, the disease in existing subgrade is widespread and serious. The subgrade subsidence in Baotou-Xi’an Railway is quite serious, which has great effects on the safety and economical of railway. In order to meet with the demand of heavier axle load and faster speed, it is necessary to subgrade to be strengthened.Several detection methods are used to confirm the problems of the subsidence subgrade. Based on the analysis of the detection results, oblique grouting compaction pile is put forward for subgrade reinforcement. The advantage of this method is not affecting the normal operation. Because of high slurry filling rate, high compressive strength and the better reinforcement effect, oblique grouting compaction pile is a good measure for treatment of subgrade subsidence at present.To simulate grouting compaction pile into the subgrade slope for subgrade strengthen, finite element analysis model is established by finite element analysis software ABAQUS. Based on the consideration of different parameters of compaction pile, the static deformation and dynamic behavior of transition subgrade and embankment are calculated. The relationships between the layout parameters including the horizontal angle, density and modulus of elasticity of piles for the effect of subgrade reinforcement are summed up. When the horizontal angle is10°to15°, the compaction pile is more effective, and can further inhibit the transition section deformation of10%to15%.The pile density in1.5m to2m is appropriate. The smaller density will lead to the interactions between soil compaction. When the modulus of elasticity is more than5000MPa, the deformation suppression of upgrading will be very limited. According to the static calculation, the most appropriate compaction pile layout parameters are selected for dynamic analysis. The results show that:the dynamic displacements of surface of ballast bed and subgrade decrease obviously after reinforcement, and the dynamic displacements of subgrade are less than the limit. The maximum acceleration of subgrade can reduce about26%.The dynamic displacement and acceleration will attenuate along the depth of subgrade. It is better to strengthen measures to reduce the dynamic response of subgrade.From what has been discussed above:the applications of oblique grouting compaction pile on subgrade strengthen are feasible and effective. It can provide some reference for the railway speed picking up in the future.