基岩注浆截水帷幕在城市40m超深基坑工程及#br# 紧邻地铁保护中的应用

深圳市恒大中心项目基坑开挖深度38.95～42.25m，围护结构北侧3.0m为运营地铁盾构隧道，场地存在压扭型破碎带自西向东穿过项目基坑，为项目基坑施工和紧邻地铁盾构隧道安全带来严重威胁，采用基岩注浆技术施做截水帷幕进行地铁保护。文章从帷幕设计、注浆工艺、质量检测、问题处理四个方面梳理提炼项目中相关经验，形成关键技术问题，并在此基础上，梳理城市深基坑工程中基岩注浆截水帷幕项目特点及技术应用思路。研究认为，岩面/起灌面精确判断、孔口管防漏及管控、残积层注浆帷幕处理是技术应用的关键问题，并提出了相应解决建议，可为华南地区花岗岩地层类似项目提供参考。

Application of bedrock grouting curtain for cutting off water in the protection #br# of a 40m foundation pit and shield tunnels nearby

 The Shenzhen Evergrande Center foundation pit, with the excavation depth of 38.95～42.25m, is only 3m away from operating shield tunnels nearby and a compression and torsion fracture zone was found in the granite strata below. To protect foundation pit and tunnels from underground water hazard during excavation, a grouting curtain for cutting off water at the bedrock is applied. In this passage, main issues of the curtain design, grouting process, quality inspection, problem was solutions during this case are included; the characteristics and application path of bedrock grouting curtain in urban deep foundation pit are discussed. The research shows that accurate judgment of starting grouting surface, leakage prevention of orifice pipe, treatment of eluvium layer should be focused on and the countermeasures are included.