大秦线2万t货物列车条件下线桥设备试验研究

选取大秦线5个轨道、1个路基和9个桥梁试验工点,进行2万t列车的运行和制动试验,研究大秦线轨道、桥梁和路基的动力性能。结果表明:2万t试验列车通过典型线、桥、路基和道岔地段时,实测脱轨系数、轮重减载率和轮对横向力以及道岔尖轨开口量等指标均在安全限度内,说明在大秦线开行2万t货物列车是安全可行的。2万t试验列车作用下的轨道动力响应和各项位移参数与普通列车正常运营时基本相当,但2万t试验列车车辆由车轮扁疤产生的轮轨垂直力最大值达到277 kN,会对轨道结构产生显著的破坏作用;桥梁的挠度和振动参数基本在安全控制范围内;路基的动应力值基本在45 kPa以内,轴重由21 t增加到25 t后,路基动应力只增加2 kPa左右,但2万t列车通过时相邻两转向架4个车轮产生的路基动应力分布为1个梯形形式,而6 000 t列车通过时为2个交叠的梯形形式。

Test Study on Track Bridge and Subgrade Equipment of Datong-Qinhuangdao Railway under 20 000 t Freight Trains

In order to study the dynamic performances of track,bridge and subgrade of Datong-Qinhuangdao Railway,the operation and brake tests,under 20 000 t heavy trains,are conducted at five testing sites of track,one of subgrade and nine of bridge.Results showed that the measured vehicle derailment factors,wheel unloading rates,lateral forces of wheelset and the opening sizes of switch rail are all under safety limit values while 20 000 t testing trains passing through the typical sections of track,bridge,subgrade and turnout.This indicates that it is safe and feasible for 20 000 t freight trains running on Datong-Qinhuangdao Line.The dynamic response and various kinds of displacement parameters of track under 20 000 t testing trains are basically similar to those under ordinary freight trains.However,the maximum value of wheel-track vertical force caused by the wheel flats of 20 000 t testing trains is 277 kN,which will obviously damage the track structures.Basically,the deflection and vibration parameters of bridges are within the range of safety control.The dynamic stress values of subgrade are mostly below 45 kPa,and the increasing value is only 2 kPa while the axle weight increased from 21 to 25 t.The distribution of dynamic stress caused by the four axles of two adjacent bogies of 20 000 t testing train is trapezoid,while correspondingly the 6 000 t testing train is two overlapped trapezoids.