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为研究以中—强膨胀土为地基的高速铁路路堑基床在不同服役环境下的动静态特性,在实验室内进行1∶1大比例尺模型试验,分别对基床在干燥状态、降雨和地下水位上升3种服役环境下以4 Hz频率进行100万次激振,监测路堑基床不同位置的动态响应和变形规律。结果表明:轨道正下方位置基床范围内的动应力主要受服役环境影响,与激振次数关系不大;动应力沿深度的衰减曲线近似成二次曲线型;膨胀土路堑基床变形受服役环境的影响大于振动次数;干燥状态和降雨时,基床变形随着振动次数的增加先增大后趋于稳定,地下水位上升时,基底膨胀土膨胀变形,并引起基床产生回弹变形;基底膨胀土干缩湿胀过程中的“过程性变形差”会造成轨面标高反复变化,极大的增加线路维护工作量。
In order to study the dynamic and static characteristics of high-speed railway bed with medium-strong expansive soil as the foundation, the 1: 1 large-scale model test in the laboratory was carried out. The effects of bed dryness, rainfall and groundwater Bit rise Three kinds of service environment with 4 Hz frequency of 1 million times the vibration, monitoring the dynamic response and deformation of different positions of the bedrock law. The results show that the dynamic stress in the bedrock below the orbit is mainly affected by the service environment and has little to do with the number of exciting times; the attenuation curve of dynamic stress along the depth is approximately quadratic curve; the deformation of bedrock of expansive soil is in service The influence of environment is greater than the number of vibration; in the dry state and rainfall, the deformation of the bed first increases and then becomes stable with the increase of the vibration frequency. When the groundwater level rises, the expansive soil of the foundation expands and deforms, The “poor processability” of shrinkage and wetting in the expansive soils of the basement causes repeated changes in elevation of the rail surface, greatly increasing the workload of line maintenance.