武汉地区一级阶地岩溶处理措施探讨及工程实践

Discussion and Application of Karst Treatment Measures for First-class Terrace in Wuhan Area

为了解决地铁穿越武汉一级阶地沙漏型岩溶地质的岩溶治理问题,以地铁6号线红建路站及两端区间岩溶勘察、设计、施工处理为基础,总结溶洞大小、竖向分布规律、充填和发育规律等特点,分析沙漏型岩溶地质塌陷机制和风险。根据武汉地区浅层岩溶特点,总结岩面以下15 m岩层帷幕注浆阻隔后再溶洞充填注浆的处理思路。地铁车站采用岩层帷幕注浆、溶洞充填注浆、地下连续墙牛腿、土层抽条旋喷加固等岩溶处理方法。区间隧道考虑岩溶塌陷角、地面施工条件等采用岩层帷幕注浆、溶洞充填注浆、砂层隔离桩等处理方法。在6号线岩溶注浆施工中探索并使用了新的岩溶注浆跟管成孔工艺、浆液流量监测工艺等新技术,适合武汉一级阶地的岩溶注浆浆液配比和终浆标准,验证了沙漏型岩溶处理思路和处理措施的合理性。

When metro tunnel crosses hourglass type Karst of first-class terrace in Wuhan area, countermeasures should be adopted.Hence, the dimension, vertical distribution law, filling and developing law of the Karst are summarized, and the collapse mechanism and risk of hourglass type Karst are analyzed based on Karst surveying, design and treatment of Hongjianlu Station and sections ahead of and behind on Wuhan Metro Line No.6.According to the features of shallow Karst in Wuhan, the Karst treatment idea of filling grouting after curtain grouting of rock 15 m below rockface is summarized.The measures, i.e.rock curtain grouting, Karst cave filling grouting, underground diaphragm wall bracket, soil layered jet grouting reinforcement, etc., are adopted for metro station, and those, i.e.rock curtain grouting, Karst cave filling grouting, sandy soil separation pile, etc., are adopted for tunnel sections.Furthermore, new technologies of Karst grouting with tube pore forming, slurry flow monitoring, etc.are also adopted in Karst grouting of Line No.6, and the slurry proportions and end slurry standard are discussed.The applicable results verify the feasibility of the Karst treatment idea and measures.