冻结法凿井产生杂散电流及消除方法

开滦东欢坨矿冷冻凿井穿过冲积层后进入基岩掘进,放炮前测得杂散电流高达300mA,超过电雷管的安全电流5倍多,施工被迫中断。文章对杂散电流产生的原因进行了分析,认为冻结管内氯化钙溶液是产生杂散电流的主要原因,并介绍了消除杂散电流的几种方法,使杂散电流降至0.5～20mA。

THE STRAY CURRENT PRODUCED IN SHAFT SINKING BY FROZEN METHOD AND ITS ELIMINATION WAY

At Dong Huan Tuo colliery in Kai Luan the freezing shaft was sunk and drivaged into the base rock through the alluvium. Before blasting it was measured that the stray current was high up to 300mA, The stray current exceeded the safe current in the electric fuse by more than five times. So the operation had to be stopped. The articte analyses the causes from which the stray current results.It considers that the solution of calcium chloride in the freezing tube is the main cause of producing the stray current. Finally the article introduces some method of eliminating the stray current which can reduce the stray current between 0.5 to 20mA.