架空式桩板结构路基静动力特性试验研究

Experimental study on static and dynamic characteristics of overhead pile-plate structure subgrade

针对常规路基在平原地区和岩溶地区建设中面临占地大、合格填料缺乏、地基处理工程量大及费用高等问题,设计一种具有一定脱空高度的架空式桩板结构路基。为了研究架空式桩板结构路基静动力特性,依托贵南高铁某架空式桩板结构路基试验段工程,开展架空式桩板结构路基静动力特性室内模型试验。试验结果表明:竖向静载作用下,结构应力随荷载值增加呈线性增大,结构整体处于线弹性工作阶段,托梁能一定程度减少应力在承载板中的集中分布。水平静载作用下,结构最大变形量出现在断轨力加载工况,为0.159 mm,换算至原尺模型为1.113 mm,变形量较小,架空式桩板结构路基具有较大的纵横向结构刚度。在1~5 Hz变频动载作用下,结构最大动加速度和动位移响应均出现在2号跨加载工况,承载板及托梁最大动加速度分别为10.10 mm/s^(2)和4.54 mm/s^(2)。结构最大动位移值为0.189 mm,换算至原尺模型为1.323 mm,远小于我国现行高速铁路标准路基竖向动位移控制值3.5 mm。变频动载试验数据显示,架空式桩板结构路基整体未产生异常振动响应现象,反映架空式桩板结构路基在1~5 Hz加载频率范围内不会发生共振。静动力试验结果综合表明,架空式桩板结构路基具有良好的受力与变形协调特性和振动特性。研究成果可为架空式桩板结构路基的推广应用提供支撑。

Aiming at the problems of large land occupation,lack of qualified filler,large amount of foundation treatment works and high cost in the construction of conventional subgrade in plain and karst areas,an overhead pile-plate structure subgrade with a certain void height was designed.In order to study the static and dynamic characteristics of the overhead pile-plate structure subgrade,the indoor model test of the static and dynamic characteristics of the overhead pile-plate structure subgrade was carried out according to the test section project of Guizhou-Nanning high-speed railway.The test results show that under the action of vertical static load,the structure stresses increase linearly with the increase of load value.The whole structure is in the linear elastic working stage.The supporting beam can reduce the concentrated distribution of stress in the bearing plate to a certain extent.Under the action of horizontal static load,the maximum deformation of the structure appears in the loading condition of the rail breaking force,which is 0.159 mm.The maximum deformation converted to the original scale model is 1.113 mm.The deformation of the subgrade structure is small,which reflects that the overhead pile-board structure subgrade has good vertical and horizontal structural stiffness.Under the action of 1~5 Hz variable frequency dynamic load,the maximum dynamic acceleration and displacement response of the structure appears in the quarter-span loading condition.The maximum dynamic acceleration of the bearing plate and the supporting beam is 10.10 m/s^(2)and 4.54 m/s^(2),respectively.The maximum dynamic displacement of the structure is 0.189 mm.The maximum dynamic displacement of the structure converted to the original scale model is 1.323 mm,which is far less than the control value of 3.5 mm in vertical dynamic displacement of current high-speed railway subgrade standard.Variable frequency dynamic load test data show that the overhead pile-plate structure subgrade does not produce abnormal vibration response.The overhead pile-plate structure subgrade will not resonate in the loading frequency range of 1~5 Hz.The static and dynamic test results show that the overhead pile-plate structure subgrade has good stress and deformation coordination characteristics and vibration characteristics.The results can provide support for the popularization and application of overhead pile-plate structure subgrade.