Research On The Mechanical Ptoperties Of Unballasted Track Under Land Subsidence

Because of good stability, less maintenance, long life and other advantages, unballasted track has been widely used in high-speed railway construction around the world. Foundation subsidence is one of the most common diseases of high-speed railway, subsidence and deformation is the core issue to be resolved for unballasted track to be laid on the roadbed. Due to the stiffness of unballasted track rail plate is very large, foundation subsidence will have a significant influence on the mechanical properties of unballasted track. China’s current unballasted track design, usually rarely contain subsidence design. Research on the subsidence is only considered subgrade subsidence, ignoring the effects of ground subsidence on unballasted track. In recent years, studies have shown that a growing number of foundation subsidence is largely due to ground subsidence. As the cause of ground subsidence is complex, difficult to control, irreversible and the force mechanism of unballasted track caused by subsidence is not clear, it is urgent for the mechanical properties with ground subsidence to be studied.In this paper, with the beam-body unballasted track computing theory, use finite element analysis software to establish unballasted track-roadbed coupled static model and vehicles-unballasted track-roadbed coupled dynamics model, and use them for the systematic analysis of mechanical properties of unballasted track. This paper focuses on calculation and analysis the mechanical properties of unballasted track of CRTS Ⅰ-type slab and double block laid on soil subgrade under differential subsidence, the main research work is as follows:1. Calculation and analysis on statics properties of the unballasted tracks under land subsidence. The static properties of unballasted track is calculated, under different condition such as different subsidence amplitudes, wavelengths, depths, elastic modulus of mortar, elastic modulus reduction of the base plate or support layer.2. Calculation and analysis on dynamics properties of the unballasted tracks under land subsidence. The dynamics characteristics of unballasted track is calculated, under different condition such as different subsidence amplitudes, wavelengths, elastic modulus reduction of the base plate or support layer, vehicle speeds, and acquire the vehicle transverse and vertical acceleration, acceleration and displacement of rail and track plate, as well as derailment coefficient and load reduction rate.3. Explore the land subsidence limits under Soil Subgrades:Combined with model calculations, considering vehicle safety, track structure affordability, passenger comfort, structural adjustment capacity and other factors, raise a land subsidence control limits.