Abstract:  AE information of rock brittle failure is closely related to the deformation failure process under loading, and AE will increase suddenly in the stages of expansion point before rock rupture, stress peak point, and inflection point after the peak value, respectively. In this paper, based on three-dimensional renormalization group theory, the ratio expression between the strain related to the expansion point before rock rupture and the one related to the stress peak point is obtained, and the critical ratio has a range of 74% to78% under the uniaxial loading, which has been proved by the rigid loading test of sandstone. Meanwhile, according to the analysis of test data, the strain value between the expansion point before rock rupture, stress peak point, and inflection point after peak value is nearly stable.

Key words:  , AE；renormalization group；stress-strain curve；sandstone