【摘要】 为了研究循环加载条件下岩石的变形演化规律,开展了红砂岩试件的等幅循环加载与分级等幅循环加载试验。采用CCD相机对试验过程中试件的变形图像进行采集,基于数字散斑相关方法分析了等幅循环加载过程中试件的非均匀变形演化规律。分析研究发现:循环加载过程中,随着循环次数的增加,试件的非均匀变形场逐步演化,变形局部化现象愈加明显;非均匀变形在循环加载过程中存在时间滞后和变形累积特征,且分级等幅循环加载过程中其峰值应力的增加会使非均匀变形的滞后特性与累积特征更加明显;在试件发生破坏前,加载顶点和卸载底点的非均匀变形指标数值逐渐接近。研究循环加载作用下岩石的非均匀变形演化规律,可为岩石破坏提供新的前兆信息。更多还原

【Abstract】 In order to study the deformation and evolution laws of rock under cyclic loading conditions, the constant amplitude cyclic loading tests and multistage constant amplitude cyclic loading tests of red sandstone specimens have been carried out. The deformation images of specimens during the tests have been collected with CCD cameras, and based on the digital speckle correlation methods, the evolution laws of non-uniform deformation of specimens in the process of constant amplitude cyclic loading have been analyzed. The research results have shown that during the cyclic loading process,with the increase of cyclic numbers, the non-uniform deformation field of specimen gradually evolves and the deformation localization phenomenon is more and more obvious. The characteristics of time hysteresis and deformation accumulation in non-uniform deformation exist during the cyclic loading process, and the increase of peak stress in the process of multistage constant amplitude cyclic loading will make the hysteresis and accumulation characteristics of non-uniform deformation more obvious.Before the failure of rock specimen, the values of non-uniform deformation index at the peak point of loading and the bottom point of unloading are getting closer. The study on the evolution laws of non-uniform deformation of rock under cyclic loading can provide new precursory information for rock failure.更多还原