Abstract: The lifting of railway roadbeds via grouting is often uneven, and the effectiveness of the grouting is difficult to guarantee. To address this, the experimental study on soil pressure characteristic unit cell attached to capsular tube grouting was carried out, and the comparative analysis on the changes in additional soil pressure in the stratum caused by different grouting methods was conducted. The experimental results show that compared to direct grouting, capsular tube grouting demonstrates better linearity and controllability in the increase of additional soil pressure. In contrast to bag grouting, the additional soil pressure increase of capsular tube grouting exhibits a directionality where the radial is greater than the longitudinal. The maximum radial expansion of the capsular tube is limited by its diameter. When the grouting volume approaches full capacity, uniform compression of the surrounding soil can be achieved without longitudinal expansion, and basically no compression occurs during the grouting process. It should be noted that after the grouting material solidifies, free water may seep out. It is recommended to appropriately reduce the water content or add water-reducing agents to ensure long-term effectiveness. Based on the good directionality and controllability of capsular tube grouting, it can be used in subgrade lifting projects to replace traditional direct grouting methods, effectively avoiding grout leakage and slope deformation and cracking.

Key words: railway engineering; railway roadbed; subgrade settlement; grouting uplift; earth pressure; directional uplift

摘要： 针对铁路路基在注浆时存在抬升不均匀且注浆效果难以保证的问题，开展了囊管注浆附加土压力特性单元体的试验研究，并与其他不同注浆方式所引起地层附加土压力变化进行对比分析。试验结果表明：较直接注浆，囊管注浆在附加土压力增长方面表现出更好的线性与可控性；相较于囊袋注浆，囊管注浆的附加土压力增长具有径向大于纵向的方向性，其径向最大扩张量受其直径限制，注浆接近饱满时可实现对周围土体的均匀挤压，其纵向不发生膨胀，注浆过程中基本不产生挤压；需要注意的是，注浆材料凝固后可能出现自由水渗出，建议适当降低含水量或添加减水剂以保证长期效果。囊管注浆具有良好的定向性与可控性，可将其用于路基抬升工程，以替代传统直接注浆方式，并可有效避免跑浆及边坡变形与开裂。

关键词: 铁道工程；铁路路基；路基沉降；注浆抬升；土压力；定向抬升