jumbolter

After several years to jumbolter research,the hard rocks always present in the soft ones in the wall rock procedure using jumbolter,which results in changing the boring tool during the procedure.

经过几杆钻机的跟踪研究,发现杆钻机在围岩作业中遇到软岩中有硬岩夹层的现象,造成施工过程经钻具的问题。