主隧道结构散热对联络通道冻结效果的影响

 在采用人工冻结法施工的联络通道中，主隧道管片的散热对管片附近土体的冻结效果有很大的削弱作用。通过施工现场的温度监测数据，研究管片散热对联络通道中土体温度场发展状态的影响，发现管片外侧喇叭口部位土体无论在冻土温度还是在冻土帷幕的厚度上都较未受影响区相差很大，受影响区冻土帷幕厚度最小处仅为未受影响区厚度的一半，且随着冻结的持续进行，喇叭口部位土体的温度场在一定时期达到热交换的平衡状态，持续冻结对此区域的冻结效果增强不明显，只会降低未受管片散热影响区域的土体温度。绘出冻土帷幕的发展变化过程。最后在影响分析的基础上对联络通道的安全施工提出了建议。

INFLUENCE OF HEAT DISSIPATION OF MAIN TUNNEL STRUCTURE ON FREEZING EFFECT IN CROSS PASSAGE CONSTRUCTION

Heat dissipation of tunnel segments can seriously weaken the freezing effect of the soil near the segments in cross passage construction by artificial freezing method. Based on the field monitored temperature data，a study is conducted to investigate the influence of segments heat dissipation on the development of temperature field. The result shows that the influence of heat dissipation is significant both on the temperature field and the thickness of frozen soil wall，both of which are seriously weakened，and that causes a large gap at the opening of the cross passage compared with the uninfluenced area. The thickness of the frozen soil wall in the influenced area at worst just is half of that in the uninfluenced area，which is very dangerous for construction. With the continuation of freezing，the temperature field in the influenced area gradually reaches an equilibrium state of heat exchange，and the temperature changes little even if the freezing time is prolonged，which only lowers the temperature and improves the thickness of the frozen soil wall of uninfluenced area. On the basis of analysis above，the process of frozen soil wall development is plotted. At last，some suggests are brought forward to guide construction of similar projects.