关键词: 岩芯连续刻划, 自适应刻划, 破碎比能, 划痕强度, 致密砂岩

Abstract: Accurate and rapid acquisition of rock strength parameters is essential for ensuring safety in rock engineering. Conventional methods, including cutting and coring, end face polishing, and compression crushing, are time-consuming. This study introduces a continuous rock core scratching technique as a fast and convenient alternative, causing only minor surface scratch. This method allows for the rapid determination of uniaxial compressive strength, internal friction angle and cohesion. To address the limitations of traditional fixed-depth scratching methods that ignore rock core surface roughness, this study introduces a real-time adaptive adjustment technology. This innovation precisely senses surface characteristics and adjusts scratching depth dynamically. Corresponding adaptive continuous scratching equipment has been developed. A series of continuous scratching experiments was conducted on tight sandstone using three modes: fixed depth, adaptive equal division, and adaptive point selection. Results indicate that, compared to standard compression tests, the maximum error in rock strength parameters from the adaptive scratching test was 10.57%. Furthermore, compared to fixed-depth scratching, the accuracy of uniaxial compressive strength testing using adaptive equal division and adaptive point selection scratching improved by 44.44% and 53.09%, respectively. The study also discusses the sources of strength testing errors caused by different scratching modes and clarifies the applicable scenarios for sharp and blunt cutting heads. Core adaptive continuous scratching test technology provides a simple and efficient new method for rapid testing of rock mechanics parameters, optimizing load measurement errors resulting from traditional methods’ inability to ensure constant actual scratching depth.

Key words: continuous scratching of rock cores, adaptive scratching, crushing specific energy, scratch strength, tight sandstone