高速铁路沉降无砟轨道结构注浆整体抬升修复关键技术

Key technologies of remedying settlement of high speed railway ballastless track by lifting whole structure and jet-grouting under it

我国部分无砟轨道线路地基、路基的工后沉降量较大,超过扣件的可调整范围,导致线路平顺性无法修复,列车不得不限速行驶。针对这一难题,通过大量的室内缩尺试验、现场实尺模拟对沉降无砟轨道结构注浆抬升用材料、装备和工艺等进行了系统研究。首次在实尺模型的基础上,结合破坏检查试验,对抬升实施效果进行了全面验证,并结合工程实践,形成了无砟轨道结构整体注浆抬升成套技术。该技术采用在级配碎石层注浆的方式,利用注浆压力及注浆材料膨胀力实现轨道结构的平稳抬升,能在不影响线路正常运营的情况下,利用天窗时间对无砟轨道结构进行整体抬升,恢复沉降地段的线路平顺性及扣件系统可调整量。与传统水泥基注浆技术相比,本技术具有施工设备小型轻便、物流简单、组织灵活、精度可控、次生病害少等显著优点。本文从抬升原理、注浆材料、设备工装、施工工艺、技术特点及其现场应用等方面对沉降无砟轨道结构整体注浆抬升关键技术进行了系统介绍,可为我国无砟轨道沉降病害修复与整治提供借鉴。

Subgrade settlement is found to be the major defect for some ballastless lines in China,as fastening adjustment can no longer ensure the smoothness of the line,which leads to the speed-limit operation of the train.U nder such background,Out indoor scaled test and in-situ full-scale modeling were carried to study the material,equipment and technique applied in the grouting of ballastless track.This ground-breaking study builds full-sized model to simulate the situation and conducts destructive test,so as to examine the lifting effect of the grouting procedure.Thanks to such effort and the best practice accumulated in previous projects,the workf lowfor overall grouting of ballastless track is proposed,where the grouting method for graded crushed-stone layer is applied.The approach is able to lift the track structure smoothly to its previous level,as it takes use of the grouting pressure occurred and the swelling force of the grouting material,and any minor irregularity can be mended in fastening adjustment.It needs to be noted that the reparation can be carried out within the possessive interval for construction,in other words it does not disrupt the operation plan.Compared with the traditional cement-subgrade grouting technique,the newapproach promises straight-forward workflowand limited secondary defects,in the meantime,it stands out in its f lexibility in scheme arrangement,precision in quality control,lightness and size of the equipment applied.The paper gives a systematic overviewon the key technology in the grouting of ballastless track settlement,as it covers the lifting principles,grouting material,equipment and tools,engineering technique,technical features and the best practice arrived fromin-situ application.It intends to contribute its due part to the reparation and treatment of balastless track settlement.