振动荷载下红层软基路堤动力响应及刚度敏感性分析

Analysis of Dynamic Response and Stiffness Sensitivity of Red-bed Soft Ground Embankment under Vibration Load

为扩大红层区路基填料的选用范围,以西南某高速铁路路基挖方及隧道弃渣红层软岩作为路基填料,建立有砟轨道-路基系统模型,研究列车振动荷载作用下路基结构的动力响应;结合正交设计试验和GRA分析法确定基床动应力的参数敏感性排序。结果表明:动应力和动位移在路基横向都呈马鞍形不均匀分布,且动应力分布不均匀性更大;道床材料弹性模量的增加能有效降低基床表面的动应力,但动位移几乎不受影响;提高路基本体和地基材料的弹性模量时,动应力虽略有增大,但能抑制动位移的增加,减小塑性变形;下部各结构层应合理匹配刚度,路基本体刚度、地基刚度不应过大,以其弹性模量分别不超过90、80MPa为宜。

In order to expand the selection range of subgrade filling in red bed region,taking spoil residue from excavation and tunneling of red-bed soft rock as the filling of the high-speed railway subgrade in the Southwest,a ballast track-subgrade system model for the embankment was established,and the dynamic response of subgrade structure under the action of train vibration load was studied.Combined with the orthogonal test and GRA analysis,the parameter sensitivity ranking of subgrade dynamic stress is determined.The result shows that,the dynamic stress and dynamic displacement distribute unevenly in saddle shape on the transverse direction of subgrade,and the distribution of dynamic stress is more uneven;the increased elastic modulus of track bed material can effectively reduce the dynamic stress on the surface of foundation bed,but there is almost no effect on the dynamic displacement;when the elastic modulus of the subgrade body and the foundation material is increased,although the dynamic stress increases slightly,the dynamic displacement can be inhibited to increase and the plastic deformation may be decreased;at the same time,each lower structural layer shall be matched a proper stiffness,and the subgrade body and the foundation shall not have too large stiffness,the elastic modulus of the material is appropriate not to exceed 90 MPa and 80 MPa respectively.