无砟轨道路基基床翻浆注胶加固模型试验研究

Model experimental study on the injection reinforcement of mud pumping in subgrade bed of ballastless track

为研究无砟轨道路基基床翻浆注胶加固方法,建立无砟轨道路基室内试验模型,分析无咋轨道路基在基床表层处于正常状态、浸水饱和状态和翻浆注胶加固后动力响应规律。试验结果表明:荷载加载50万次,与基床表层正常状态相比,基床表层处于浸水饱和状态时,基床表层动应力减少19.7%,底座板振动位移与振动加速度分别增大89.5%和75.3%。基床翻浆注胶加固后,与基床表层处于浸水饱和状态相比,基床表层动应力增大19.0%,底座板振动程度降低,底座板与基床表层振动比由9.4:1变为2:1;对比基床正常状态,基床表层动应力与底座板振动位移、振动加速度均略有减小。试验后揭开底座板,基床表层顶部翻浆区域级配碎石与注入胶体胶结形成复合体,填充了底座板与基床表层之间空隙。基床翻浆注胶加固后,恢复了对底座板的支承能力,底座板的异常振动得到改善。

In order to study the method of injecting reinforcement of mud pumping in subgrade bed of ballastless track,an experimental model of the ballastless track subgrade was established to analyze the dynamic response characteristics of the ballastless track subgrade when top layer of subgrade bed was in three conditions(i.e.,the normal condition,water saturated condition and glue-injection reinforced condition).The results show that when loading cycles is 500 thousand times,the dynamic stress of top layer of subgrade bed in water saturated condition decreases 19.7%,while the dynamic displacement and vertical acceleration of concrete base of the ballastless track increase 89.5%and 75.3%respectively,compared with the top layer of subgrade bed in normal condition.Compared with the top layer of subgrade bed in water saturated condition,the dynamic stress of the top layer of subgrade bed with mud pumping after reinforced increases 19.0%,while vibration of the concrete base of the ballastless track is reduced,such as the vibration ratio between the concrete base and the subgrade surface changes from 9.4:1 to 2:1.However,the dynamic stress of the top layer of subgrade bed and the dynamic displacement and vertical acceleration of the concrete base after the subgrade bed with mud pumping reinforced by glue injection reduce slightly compared with the top layer of subgrade bed in normal condition.Besides,it is found that a complex layer made of injected glue and graded crushed stone in the mud pumping zone fills interspace between the concrete base and the top layer of subgrade bed,when the concrete base is lifted up after the test.This shows that the bearing capacity of subgrade bed to the concrete base can be restored and then the abnormal vibration of the concrete base be improved effectively after mud pumping in the subgrade bed reinforced by glue injection.