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管幕冻结法是利用管幕配合冻结止水措施解决复杂建设条件下暗挖施工的一种创新性工法,该工法利用管幕顶管内冻结管路对管间土体进行冻结止水,在顶管管幕和冻结土体的超前支护下实施隧道暗挖施工。文章以港珠澳大桥珠海连接线拱北隧道冻结方案为例,利用数值模拟手段对积极冻结期不同土层的冻结效果及圆形冻结管、异形冻结管开启时间进行了研究,结果表明圆形冻结管和异形冻结管宜同步开启。对维护冻结期开挖断面温度、风速进行模拟分析,结果表明开挖断面内空气温度宜控制在25℃,风速对冻结效果影响不大。
Pipe curtain freezing method is the use of pipe curtains with frozen water sealing measures to solve complex construction conditions under the excavation of an innovative method of work, the method of using the pipe curtain pipe top tube frozen soil pipe between the pipe to freeze the water, Tube curtain and frozen soil ahead of the implementation of tunnel undercutting construction. Taking the freezing tunnel project of Gongbei Tunnel of Zhuhai-Zhuhai-Hong Kong-Zhuhai-Zhuhai-Zhuhai-Dalian Bridge as an example, the freezing effect of different soil layers during the active freezing period and the opening time of circular frozen tubes and deformed frozen tubes were studied by numerical simulation. The results show that the circular freezing Tube and shaped frozen tube should be opened simultaneously. The simulation analysis of the temperature and wind speed of the excavation section during the freezing period shows that the air temperature in the excavation section should be controlled at 25 ℃ and the wind speed has little effect on the freezing effect.