Characterisation of"acoustic emission-resistivity-wave velocity"evolution in granite rupture and application to engineering detection
To investigate the coordinated evolution of cracks,acoustic emission,resistivity,and wave velocity during the brittle rock failure process,designed and conducted a series of u-niaxial loading tests on granite,revealing the response characteristics of these three signals during crack evolution in rock under loading,through field measurements,the change laws of resistivity and wave velocity during geological exploration were also obtained.The results show that the failure of brittle rock is a process of transition from a"low-energy stable disordered state"to a"high-energy unstable ordered state",and the crack evolution transforms from ran-dom disordered expansion to concentrated and ordered banding,exhibiting self-organized critical characteristics.The probability density of acoustic emission energy in brittle rock ex-hibits a linear distribution,and the energy evolution during failure follows a power-law distri-bution.The power-law distribution curve gradually approaches the overall power-law distribu-tion in the later stage of loading under high local stress levels,indicating that rocks in a high-energy unstable state are more prone to sudden failure.The electrical resistivity,ultrasonic wave velocity,and acoustic emission show staged response characteristics along with crack e-volution during the rock failure process.After the rock enters the stable and unstable crack ex-pansion stages,the wave velocity damage variable and acoustic emission damage variable can be used to describe the rock damage characteristics.Comprehensively considering the crack vol-umetric strain,acoustic emission,electrical resistivity,and wave velocity can accurately identi-fy the characteristic stress before the peak strength of rock.Through field measurements of ul-trasonic wave changes,the formation can be divided into four levels:intact,relatively intact,fractured,and highly fractured.Fractured and water-bearing formations exhibit low wave ve-locity and low electrical resistivity characteristics.Electrical resistivity and wave velocity can verify and complement each other,providing a theoretical basis for the quality assessment of surrounding rock in deep underground engineering and real-time monitoring of rock mass dam-age.
crack evolutionresistivitywave velocityacoustic emissionbI valueself-organ-ized critical point
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