Polymer Injection Rehabilitation Technology for Lifting Differential Settlement of Turnout Ballastless Track

Abstract

The turnout ballastless track is an advanced track structure with high stability and integrity. However, due to complicated geological conditions, local groundwater level declined, and many other unavoidable objective reasons, the roadbed foundation of some railway lines appeared large uneven settlement deformation, so the above turnout ballastless track concrete structure also experienced uneven settlement accordingly. Compared with ballast track which could be restored by increasing the ballast under the sleepers simply, the smoothness of turnout ballastless track could only be restored by adjusting the thickness of the base plates of fastener system accordingly. But if continuous settlement deformation exceeded the specified allowed adjustable range of the fastener system, the smoothness of ballastless track diminished, the speed of passing trains had to be limited to ensure the safety. In order to solve this global challenging problem, we systematically studied polymer injection rehabilitation technology through a series of indoor reduced scale tests and field full scale simulations with real ballastless track concrete structure. We verified the effect of uplift rehabilitation and filling quality of grouting material through destructive experiment inspection. And combined with engineering practices and its coring samples strength test, the Polymer injection rehabilitation technology for turnout ballastless track in settlement roadbed sections had been studied and developed. This technology could restore the smoothness of railway and the adjustable range of fastening systems without affecting the normal daily operation of the railway lines. Compared with traditional cement grouting technology, this rehabilitation technology possessed significant advantages including small light construction equipment, simple logistics, flexible organization, high uplifting precision, and little additional load. This technology provided valuable technical support and useful references for restoring the smoothness of turnout ballastless track which appeared large uneven settlement deformation.