路基注浆对高速铁路轨道-路基体系动力特性的影响

翻浆冒泥是多雨地区铁路路基的常见病害，土颗粒流失后导致道床脱空，影响列车安全运行。高聚物注浆是修复路基翻浆冒泥的有效手段，但注浆对轨道-路基体系动力特性的影响有待进一步研究。通过全比尺无砟轨道路基模型试验重现了列车运行荷载下路基的翻浆冒泥现象，开展了路基注浆驱水和填充加固试验，测定了正常路基、路基翻浆冒泥及注浆修复后等过程的轨道-路基动力学特性变化。结果表明：无砟轨道路基产生翻浆冒泥后底座板下方产生局部脱空、列车低速通过时轨道板振动就明显加剧，而列车高速运行产生的轨道板振动速度达到正常路基的2.6倍；对翻浆冒泥病害区进行注浆治理后，注浆材料能够有效填充脱空区域并加固病害区土体，轨道结构的振动速度明显降低。进一步的数值分析表明当注浆形成的填充体弹性模量在5×10~4～1×10~6 Pa区间时才能有效降低轨道板的振动响应，沿轨道方向的注浆加固长度增加会导致轨道振动变大，需根据实际翻浆冒泥范围确定合理的注浆加固范围。

Influence of injection remediation on dynamic behaviors of a high-speed railway track-subgrade system

Mud pumping is a common disease of railway subgrade in rainy regions.The loss of soil particles leads to gaps of roadbed,adversely affecting safe operation of trains.Injection with polymer materials is an effective method for subgrade remediation,but further study is needed on injection remediation influence on dynamic behaviors of high-speed railway track-subgrade system.Based on the full-scale model tests of ballastless track-subgrade,mud pumping under train moving loads could be repeated in the laboratory,and injection remediation test was also carried out to study changes of dynamic behaviors of track-subgrade.Results show that when the subgrade suffers mud pumping,local cavity underneath concrete base also intensifies the vibration of the track slab when the train passes at low speed,and the vibration velocity of the track slab caused by high-speed train loads increased to 2.6 times compared with normal condition.It is found that the injection material fills the interspace between the concrete base and the subgrade after injection remediation,which reduces the vibration velocity of the track structure.Further numerical analysis shows that when the elastic modulus of the filler created by injection reaches between 5×10⁴and 1×10⁶Pa,the abnormal vibration of track slab can be improved effectively.The vibration velocity of the track slab increases with the length of injection area.The reasonable treatment zone thus should be determined by the actual mud pumping area.