Abstract: Currently recognized as the best form of oil storage, underground oil storage in rock cavern is supported only by bolt-shotcrete without lining. Bond strength plays an important role in transmitting stress to ensure the collaborative work between shotcrete and surrounding rock; as a result, bond strength is an important indicator for analyzing and evaluating the structural stability and construction quality in underground oil storage in rock cavern.In this research, several kinds of methods were adopted to test the bond strength between shotcrete and surrounding rock in a underground oil storage in rock cavern in south China. Results suggest that in-situ tensile method by drilling shotcrete specimen with a diameter of 50 mm is not suitable for underground oil storage in rock cavern. When the diameter of test specimen is increased to 100 mm, the success rate of specimen production for in-situ tensile test has greatly improved, and the tensile test results are reliable as the lower limiting value of bond strength. Meanwhile, result of laboratory tensile test by cutting panel-formed shotcrete with rock block is adopted as the upper limiting value of bond strength. In summary, the aforementioned two methods, namely, in-situ tensile method by drilling shotcrete specimen with a diameter of 100 mm, and tensile test by cutting panel-formed shotcrete with rock block, are recommended to evaluate the bond strength comprehensively. In other words, the results of the former could be referenced as the lower limiting value of bond strength and the results of the latter as the upper one. The research findings offer important application reference for the structural stability and construction quality in underground oil storage in rock cavern.

Key words: underground oil storage in rock cavern, shotcrete, bond strength, in-situ tensile test by drilling, laboratory tensile test by cutting panel-formed shotcrete with rock block