Research on Measurement Method of Wheel-rail Vertical Force of Urban Rail Transit

Abstract

[Objective] A large number of tunnel diseases usually occur during the operation of urban rail transit, and the main cause of the diseases is the wheel-rail force. Therefore, it is necessary to study the method of measuring the wheel-rail vertical force without affecting the normal train operation. [Method] With the descending section between Chadianzi Station and Yipintianxia Station of Chengdu Metro Line 7 as the research object and based on the moment difference theory, a finite element model of steel rail under static load and dynamic load is established by using ANSYS software, and a numerical simulation analysis is conducted on it. The calibration test on a 2-meter-long, 3-span rail is carried out in the laboratory. [Result & Conclusion] The numerical simulation analysis of the static load shows that the rail measuring points can be chosen on both sides of the upper surface edge of the rail bottom in the middle of the rail span. When the vertical load is applied to the middle of the span, the strain at the measuring points along the rail direction is the largest, and the strain increases linearly with the vertical load. The calibration coefficient measured by calibration test is 0.626 0×106 kN, while that obtained by numerical simulation is 0.644 1×106 kN. The deviation between the two is only 2.8%. Therefore, the calibration coefficient can be determined by static load calibration test. The measurement method of the wheel-rail vertical force can better evaluate the safety of track structure and train operation. The hidden hazards can be timely detected and corresponding measures be taken for repair and improvement.

Keywords

• urban rail transit
• train
• wheel-rail vertical force
• measurement method