济南黄河隧道超大直径盾构端头冻结加固技术

始发和接收段为盾构隧道施工过程中的重要风险源，特别是在富水地层中的防水措施十分关键。冻结法已普遍被应用于处理盾构始发和接收段止水加固的问题。依托济南黄河隧道工程，对超大直径泥水平衡盾构端头冻结技术进行总结。对工程地质和周边管线等实际情况进行具体分析，计算单个洞门接收和始发的需冷量后选择合适的冻结设备，并进行盐水循环和清水循环设计；通过始发段测温孔的设置和按时间分布记录的数据，分析了加固处的降温速率和冻结壁发展情况；从冻结帷幕厚度和冻土平均温度等指标对冻结效果进行评估；最后对冻结中可能遇到的冻胀、融沉、设备故障和洞门破除等风险进行评估，并给出相应的处理方法。以上得到的数据和结论可为以后工程中的冻结加固方向提供参考。

Freezing Reinforcement Technology of Super Large Diameter Shield in Jinan Yellow River Tunnel

The starting and receiving sections are important sources of risks in the construction of shield tunnels.Especially in the water-rich stratum,the waterproof measures are critical. Freezing method has been applied to solve the problem of water stop and reinforcement of shield launching section at present. Based on the starting section of Jinan Yellow River tunnel project,the freezing reinforcement technology of super large diameter slurry balanced shield is summarized. Actual conditions such as engineering geology and surrounding pipelines are analyzed. The appropriate freezing equipment is selected after the calculation of cooling capacity,and the design of salt water circulation and clean water circulation is carried out,based on the analysis of the actual situation of the project. Through the setting of temperature measuring holes in the launching section and the data recorded according to the time distribution,the cooling rate and the development of the frozen wall are analyzed.Freezing effect is evaluated from indexes such as freezing curtain thickness and average temperature of frozen soil.Finally,the possible risks in the freezing process such as frost heave,thawing settlement,equipment failure and opening of the hole are evaluated. The treatments are arranged as well. The above data and conclusions can provide reference for the future freezing reinforcement direction.