上海长江隧道联络通道冻结优化设计研究

Study on Freezing in Construction of Connection Galleries of Yangtze River-crossing Tunnel in Shanghai

上海长江隧道共设置8条联络通道,全部采用冻结法施工。为了优化联络通道的冻结设计参数,通过对1#联络通道冻结过程的现场实测,分析冻土帷幕厚度、冻土平均温度、开挖面温度等参数的演化规律;以冻结效率为考察指标指出了原冻结方案的不足之处,并提出联络通道冻结设计的优化方案;运用数值计算方法模拟了采用优化方案时联络通道的冻结温度场发展过程,并以采用优化方案的5#联络通道的冻结实测数据为例,对比分析了优化方案的冻结效果。实践表明,优化方案下形成的冻土帷幕有效厚度大、平均温度低、冻结效率更高。对冻结方案的优化设计为后续7个联络通道冻结施工的安全性、经济性提供了重要保障。

The 8 connection galleries of Yangtze River-crossing tunnel in Shanghai are constructed by freezing method. In the paper, analysis is made on the development rules of the thickness of frozen soil curtain, the average temperature of frozen soil and the temperature of excavation face, on basis of the results of monitoring made during freezing of No. 1 connection gallery. The disadvantages of the original freezing program are discussed and optimized freezing program is proposed. Numerical simulation is made on the development of the temperature field of the optimized freezing program. The freezing effect of the optimized freezing program is analyzed. The practice shows that the optimized freezing program has advantages such as large effective thickness of frozen soil curtain, low average temperature and high freezing efficien- cy. The study guarantees safe and economic freezing of the other 7 connection galleries.