单轴循环加卸载岩石非均匀变形演化特征

摘要

In order to study the mechanic responding mechanism of rock materials under cyclic loading and unloading,uniaxial cyclic loading and unloading tests were carried out to investigate the non-uniform deformation evolution processes of granite specimens.The deformation images of specimens during the tests were collected by CCD camera and based on the digital speckle correlation method,the non-uniform deformation,the evolution laws of the characteristic parameters of the localization during cyclic loading and unloading were analyzed.The research results show that:With the increase of cycle numbers,the non-uniform deformation is more and more obvious.The statistical index Sw of non-uniform deformation increases with the increase of loading stress,and increases with the increase of cycle numbers.After the localization of a specimen appears,the extrusion displacement and the influence width of the localization band all increase with the increase of stress and cycle numbers in the subsequent cycles.%为了研究循环加卸载下岩石材料的力学响应机制,开展了花岗岩试件单轴循环加卸载非均匀变形演化试验研究.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循环加卸载过程中试件的非均匀变形、局部化影响特征参数演化规律.研究发现:随着循环次数的增加,非均匀变形现象越来越明显;非均匀变形统计指标Sw随着加栽应力的增大而增大,随着循环次数的增加而加剧;当试件出现局部化现象后,后续循环随着应力的增大及循环次数的增加,其挤压位移和局部化带影响宽度皆有所增大.