【作者】 陈玉超；

【导师】 刘波；

【作者基本信息】 中国矿业大学（北京） ， 岩土工程， 2014， 博士

【摘要】 针对立井冻结工程中存在的局部难冻地层，提出了两种差异冻结方案：冻结管差异温度冻结方案和局部地层扩孔填充导热材料冻结方案。为了验证两种方案的强化冻结效果，在试验箱体内进行了单冻结管差异温度冻结试验和外覆导热材料的冻结试验。结果表明：研发的双循环系统冻结器可实现管段差异温度冻结，两种方案均能有效调整冻结壁的厚度和平均温度，使土层得到一定程度的强化冻结。对不同流速条件下盐水和冻结管壁间的耦合换热机理进行了研究，得到了冻结过程中冻结管壁温度随时间变化曲线。随着流速的增加，热边界层厚度变薄，冻结管壁温度降低，地层得到强化冻结。基于FVM原理，建立了无渗流和渗流两种情况下的冷能消耗计算模型，并进行了数值分析，结果表明：采用差异冻结方案，无渗流地层在消耗近于相同的冷能下可对地层强化冻结，减少冻土入荒量，实现立井的早日开挖，而渗流地层可实现冻结壁的早日交圈，冷能得到优化。结合工程实例的计算表明，差异冻结对难冻地层的强化冻结效果显著。更多还原

【Abstract】 Considering local difficult-to-freeze strata (DFS) in shaft construction engineering, twointensified freezing schemes are provided in the paper: an optimization freezing suggestion offlowing different negative temperature solutions in a freezing pipe, and a scheme of reamingborehole filled with heat conduction material for local DFS. To verify the effect of intensifiedfreezing and the adjustment ability of the freezing pipe, a single freezing pipe test is conducted in amodel test box usingtwo sets of circulatory systems to provide calcium chloride solution of differentnegative temperatures for two sections of the freezing pipe. Meanwhile, artificial freezing tests,single freezing pipe is covered with heat conduction materials, are conducted. Test results show thatthe freezing pipe of dual circulation system can realize freezing of two different temperatures, andsuch two schemes can adjust the thickness of frozen wall and average temperature effectively andrealize intensified freezing.Based on coupling between fluid and solid, heat transfer mechanismbetween Calcium chloride solution and freezing pipe is studied, and the temperature curves offreezing pipe’s outer wall can be achieved by the calculation. It is proved that heat boundary layerwould be thinner when the flow velocity of Calcium chloride solution is higher, and thus the stratawould be intensified freezing. Based on FVM principle, calculation models of cold energyconsumption about no seepage strata and seepage strata are established and numetrical analysis aredone to prove the good effect of two intensified freezing schemes. The results indicate thatintensified freezing methods can intensify the freezing of strata for the same freezing time. The twoschemes can also decrease freezing time, reduce the average temperature and reduce the amount offrozen wall which should be excavated in the process of construction, though the cold energyconsumption is not increasing. For seepage strata, intensified freezing schemes can realize the frozenwall to be closed earlier, and thus cold energy consumption is optimized finally. Caclulation about aproject shows that such two intensified freezing schemes can intensify freezing coal stratumeffectively.更多还原