Abstract:  The first large underground watertight crude oil rock caverns is tested and analyzed by using the ultrasonic testing technique based on the loosen zone theory of the rock mass. The test results show that the thickness of the surrounding rock loosen zone at the gallery is between 0.5 meters and 1.3 meters. The test results provide the basis for the rock bolt design parameter. This paper also introduces methods of controlling the loosen zones and methods of rock cavern support.

Key words: Underground Caverns, Surrounding Rock loosen Zone, Ultrasonic Testing, Support Techniques