CRTS-Ⅱ型板式无砟轨道线路路基不均匀沉降限值研究

Limited value for uneven settlement of subgrade under CRTS-Ⅱ type slab track

基于列车-轨道耦合动力学理论,考虑无砟轨道各部件间及无砟轨道与路基间接触状态非线性,建立列车-路基上CRTS-Ⅱ型板式无砟轨道三维非线性有限元耦合动力学模型,在自重荷载、轨道中长波随机不平顺、轨道短波随机不平顺、路基不均匀沉降荷载、无砟轨道板温度梯度荷载共同作用下,对高速铁路CRTS-Ⅱ型板式无砟轨道线路路基不均匀沉降限值进行研究。研究结果表明:无砟轨道板温度梯度荷载对CRTS-Ⅱ型板式无砟轨道各部件受力均有比较明显的影响;在进行CRTS-Ⅱ型板式无砟轨道线路路基不均匀沉降限值研究时,有必要同时考虑轨道板温度梯度荷载的影响;对于路基上CRTS-Ⅱ型板式无砟轨道线路,路基不均匀沉降限值与无砟轨道裂缝间距有很大关系,当裂缝间距为1.3 m时,路基不均匀沉降限值由车体振动加速度控制,其限值为13 mm/20 m(即不均匀沉降波长为20 m,波幅为13 mm);当裂缝间距为2.6 m时,路基不均匀沉降限值由扣件最大拉力控制,其限值为10 mm/20 m。

A vehicle-CRTS- II type slab track on subgrade three-dimensional nonlinear finite element coupling dynamic model was established based on vehicle-track coupling dynamic theory considering the nonlinearity contacting state among components of ballastless track and the relationship between ballastless track and subgrade. With the established model, the limited value for the uneven settlement of subgrade under CRTS- II type slab track was studied under the combined action of gravity load, medium and long wave track random irregularity, short wave track random irregularity, uneven settlement load of subgrade and temperature gradient load of slab. The results show that temperature gradient load of slab has obvious influence on the mechanical charactertics of components of CRTS- II type slab track. It is necessary to take temperature gradient load of slab into account to study the limited value for the uneven settlement of subgrade under CRTS- II type slab track. The limited value for the uneven settlement ofsubgrade under CRTS- II type slab track is closely related to crack spacing of slab. When the crack spacing of slab is 1.3 m, the limited value for the uneven settlement of subgrade under CRTS-II type slab track controlled by accelation of carbody is 13 mm/20 m. When the crack spacing of slab is 2.6 m, the limited value controlled by tensile force of fastening is 10 mm/20 m.