Simulation For Compacted Parameter Standard And Research On Dynamic Response Of High Speed Railway

The subgrade playes an important role in the safety of highspeed railway. How to improve the stiffness and strength of the subgrade , reduce the settlement after construction and increase the overall stability has been an urgent problem with the increase of the running speed increasingly. Therefore,adopting scientific compacted control methods and how to reduce the effects of the increasing speed on the subgrade have been the focus in the technology research of high-speed railway subgrade in all countries. Nowdays, the foundation coefficient k30 is mainly applied in the subgrade compacted control criterion of our country and the dynamic deformation module Evd has gradually been introduced. In addition, many tests and theoretical reasearch on the dynamic response of high-speed railway subgrade have been done. In this paper, mathematics simulation analysis and research on k30 and Evd are performed based on the finite element method.A simulation model of the plate load test is established here to research on k30. The relationship between k30 and deformation modulus E is researched and the relational expression is E=0.208 k30. The influencing range of k30 test is also studied with the settlement precent as the criterion. It is founded that the influencing area in depth is about 1.1m while that on sideways is about 0.7m. In addition, the operability study on k30 of highspeed railway subgrade is done to draw the conclusion that the minimums of the surface layer of bedding , the bottom layer of bedding, the embankment underneath and the deformability modulus of ground can respectively be 45MPa,35 MPa,20 MPa and 15 MPa in the calculation and analysis of railway subgrade.A simulation model of the plate load test is established here to research on Evd. The relationship between Evd and elastic modulus(dynamic modulus) is researched and the relational expression between Evd and Ed of different kinds of soil is received. The influencing range of the Evd test is also studied with the stress and settlement as the criterion . It is founded that the influencing area of the Evd test in depth is about 1.8m while that is 0.8m on sideways. In addition.it is proposed that the relationship between Evd and k30 can be analyzed according to the relationships between Evd and Ed,k30 and E as well as Ed and E.Referring to the high-speed railway design standard , the finite element model of subgrade for dynamic analysis is established. According to the stress and deformation of subgrade under the influence of train load to analyze the rational match of the stiffness of different layers. It is founded that the influence of stiffness variation to the acceleration,velocity and settlement is the greatest , so it proves that it is reasonable to take these three indexs: the acceleration,velocity and settlement as the control parameters in high-speed railway design. The effects of composite stiffness,stiffness of surface layer of bedding,stiffness of bottom layer of bedding and embankment underneath on subgrade dynamic response are respectively analyzed and the rational match of the stiffness of different layers is received.