基于应变水平的砂岩脆性破坏声发射信息研究

Study on AE Variation of Sandstone Brittle Failure Based on Strain Level

岩石脆性破坏过程中的声发射信息与其受载变形破坏过程密切相关,在岩石破裂前的膨胀点、应力峰值点和应力-应变曲线峰值后拐点位置存在声发射会出现突增现象。利用岩石破坏的三维重整化群理论给出了岩石破裂前声膨胀点所对应的应变和岩石峰值应力对应的应变水平比值的表达式,单轴荷载条件下其临界比约为74%与78%之间,并通过砂岩刚性加载试验得到了验证;同时通过对试验数据的分析发现,岩石破裂前的膨胀点、应力峰值点和应力-应变曲线峰值后拐点位置所对应的应变值之间具有很好的比值关系。

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.