CAJ | 학술논문

针对地下有流水时盐水帷幕冻结方法无法形成封闭冻结壁的情况，采用液氮低温快速冻结的方式对未封闭区域进行补强冻结，对施工过程中土体的温度场分布进行监测和分析，得出以下基本结论：冻结管出口氮气温度低于-100℃时，冻结管内处于氮气和液氮的混合状态，可以有效发挥液氮快速冻结的优势，而供液管上开孔的结构，会影响冻结管内不同位置液氮量的分布，从而影响冻结效果。由于地下水流动会带走部分冷量，冻结区域封闭前后，土体降温速度差别较大，并且地下水的流动会影响冻结壁温度场的分布规律。由于液氮气化温度低，所以冻结形成的冻结壁温度梯度大，均匀性较差；停止冻结后，冻结孔位置土体温度升高迅速，而远离冻结孔的土体升温缓慢，这样缩小了冻结壁内的温度梯度。研究结果表明，利用液氮快速冻结的特点，进行盐水帷幕冻结下的补强冻结，可以有效封堵地下流水，解决盐水冻结不能形成封闭冻结帷幕的难题。
침대지하유류수시염수유막동결방법무법형성봉폐동결벽적정황，채용액담저온쾌속동결적방식대미봉폐구역진행보강동결，대시공과정중토체적온도장분포진행감측화분석，득출이하기본결론：동결관출구담기온도저우-100℃시，동결관내처우담기화액담적혼합상태，가이유효발휘액담쾌속동결적우세，이공액관상개공적결구，회영향동결관내불동위치액담량적분포，종이영향동결효과。유우지하수류동회대주부분랭량，동결구역봉폐전후，토체강온속도차별교대，병차지하수적류동회영향동결벽온도장적분포규률。유우액담기화온도저，소이동결형성적동결벽온도제도대，균균성교차；정지동결후，동결공위치토체온도승고신속，이원리동결공적토체승온완만，저양축소료동결벽내적온도제도。연구결과표명，이용액담쾌속동결적특점，진행염수유막동결하적보강동결，가이유효봉도지하류수，해결염수동결불능형성봉폐동결유막적난제。
The brine curtain freezing cannot form a closed frozen wall in inclined shaft because of flowing water in the ground may take away some cold energy. The method of liquid nitrogen freezing was used to strengthen the brine curtain freezing. Conclusion are drawn through analysis of soil temperature distribution data which was gained in the process of freezing construction. Firstly,mixed states of nitrogen gas and liquid nitrogen appeared in freezing pipe when the pipe export temperature is lower than -100 ℃. Opening holes on the liquid nitrogen supplying tube can affect the distribution of liquid nitrogen. As a result it may affect the freezing effect. Secondly, due to flowing water may take away some cold energy;the difference in the expansion speed of frozen soils is larger between pre and post the time that the closed frozen curtain was formed. And the flowing water can affect the temperature distribution of frozen wall. Thirdly,the frozen wall with high temperature gradient were uneven because of the low gasification temperature of liquid nitrogen. The termination of liquid nitrogen supply reduces the temperature gradient in the frozen wall. The soil temperature near the freezing hole rises faster than far away from the freezing hole after the freezing stopped. The research results indicate that the reinforcement freezing can effectively block flowing water by mean of the frozen wall formed by liquid nitrogen freezing. The problem can be solved that the closed curtain cannot be formed using brine curtain freezing.