This paper introduces four kinds of mehtods that is used to investigate crack in underground rock stratum: borehole core method, ultrasonic imaging method, borehole television method, and borehole discharge well logging method.

• 摘要本文介绍了地下岩层裂隙的4种勘察研究方法：钻孔岩芯法、超声成像法、钻孔电视法、钻孔流量测井法。