双液回退劈裂注浆在胡麻岭隧道富水粉细砂地层中的应用

摘要

胡麻岭隧道富水粉细砂地层开挖后自稳能力极差,掌子面不稳定,易坍塌,经常出现底板冒水、涌砂、涌水、沉降、初期支护变形等现象.采用常规注浆,注浆量大、工效低,效果不明显；采用化学注浆,造价又过高.大量工程实践表明,采用双液回退劈裂注浆方案,有效地改善了地层的稳定性,控制了围岩变形,且降低了施工成本.%The excavation of the Humaling tunnel in water-rich fine sand was very unstable and inclined to collapse, resulting in water inflow, gushings, significant settlement, and primary support deformation. Conventional grouting usually consumes large amounts of grout and is relatively inefficient, while using chemical grout is expensive. Based on much practice, this study found that two-component backward split grouting effectively improved the ground stability and controlled the deformation of surrounding rock as well as influenced construction costs.