特厚黏土层多圈孔冻结壁温度场实测研究与工程应用

中国国内冻结法凿井通过冲积层的厚度已突破500 m接近了600 m，收集了前10个井筒的多圈孔冻结方案和施工资料，对其中赵固一矿2个特厚黏土层冻结井，开展了多圈孔冻结壁温度场实测。分析前期冻结井存在浅部片帮、深部冻实、冷量浪费、掘进速度慢的问题。主要原因是设计的冻结壁过厚、冻结孔布置圈径不适应，中圈孔过多、内圈孔过深，中、内圈交汇后冻土向内侧扩展速度过快，主冻结孔布置在中圈冻结期间调控能力差。研究提出冻结壁厚度计算和相匹配的3圈孔冻结，以外圈为主冻结孔、中圈辅助孔、内圈防片帮孔的布孔方法，在赵固二矿3个530 m的特厚黏土层冻结井应用，有效解决了冻结与掘砌的矛盾，技术经济效益大幅提高。

Measurement and engineering application of temperature field multiple-ring hole frozen wall in extra-thick clay strata

In China the thickness of freeze sinking through alluvial layer has exceeded 500 m and is close to 600 m.Multiple-ring hole freezing scheme and construction materials of the previous 10 mine shafts are collected.Data of the temperature field of the multiple-ring hole frozen wall of two super-thick layer freezing wells in Zhaogu No.1 Coal Mine are measured.The main reasons for rib spalling in shallow area,fully frozen in deep area,slow driving,and high expense of freezing in freezing shafts are that the frozen wall is too thick,the ring diameter of holes cannot adapt to each other,the middle-ring holes are excessive,and the inner-ring holes are too deep.The frozen soil extends more quickly to inside after the intersection of inner and middle ring holes,and adjustment capacity of the main frozen hole is poor during frozen period in middle ring.The method of frozen wall thickness and the matched hole-distributing method of three-ring hole freezing which makes the outside circle as the main frozen hole,the middle circle as the auxiliary hole and the inner hole as the prevention hole for wall caving are studied.The contradiction between the freezing,driving and lining is effectively solved,and technical and economic benefits have increased greatly after the proposed method is applied successfully in three frozen walls of 530 m extra-thick clay-strata in Zhaogu No.2 Coal Mine.