Research On Polymer Grouting Uplift Technology In Settlement Zone Of High Speed Railway Ballastless Track

Because of the high-polymer grouting uplift technology can achieve better remediation effect on the subgrade settlement of high speed railway ballastless track in the skylight time,more and more engineering applications have been obtained.However,the engineering design and construction of high speed railway high polymer grouting technology relies on experience summary.The grouting process lacks theoretical support.The mechanical properties of the materials and the dynamic properties of the structures after lifting have not been studied.Therefore,this paper carried out research on high speed railway ballastless track high polymer grouting uplifting technology.The main research works are as follows:1.In this paper,the causes and hazards of the ballastless track subgrade settlement disease is summarized by researching.Through the model test,combined with the existing grouting uplift theory and slurry diffusion theory,the diffusion form of high polymer material in high speed railway ballastless track is discussed and verified: a spherical or cylindrical compacted area is formed at the nozzle of the grouting pipe,the directional fracturing occurs in the top area of the subgrade under the base plate.2.High speed railway subgrade grouting materials have been developed.According to the foaming characteristics of self-expanding two-component polyurethane polymer,the pressure resistance mold and expansion force test device of the material were developed.The mechanical properties test was carried out.The results show that as the density of the polymer material increases,the maximum expansion force,compressive strength and elastic modulus increase.3.A full-scale model of ballastless track for high speed railway was established.And the formula of grouting pressure was deduced.The research on the grouting uplift construction technology of the ballastless track subgrade was carried out,and the key construction process and technology were determined.The test found that the lift height is positively correlated with grouting pressure and grouting volume.4.The ABAQUS software was used to establish the dynamic analysis model of the high speed railway ballastless track subgrade.By comparing and analyzing the dynamic performance of the track structure before and after grouting,the effect of grouting uplift was evaluated.The results show that there is no obvious change in the dynamic performance of the ballastless track structure after grouting,and the dynamic performance of the subgrade is slightly improved.