岩样单轴压缩变形破坏与能量特征研究

基于在伺服试验机上得到的同直径不同长度大理岩样的单轴压缩试验结果,研究了尺寸对岩石变形破坏与能量特征的影响规律.结果表明,岩石长度对峰值应力前的轴向变形特性没有显著影响,但明显改变峰后的轴向变形特性;岩样长度对峰后塑性变形特性影响不大;直径一定时随着长度的增大,岩样破裂形式由竖向劈裂变为剪切破坏.随着长径比的增加,岩石破坏应变能呈幂律衰减趋势,且当长径比增加至2以后,便基本趋于恒定,不再明显减小;而岩石破坏能呈先减小后增大的非线性变化趋势.

STUDY ON THE DEFORMATION FAILURE AND ENERGY PROPERTIES OF ROCK SPECIMEN IN UNIAXIAL COMPRESSION

Marble specimens with different length-to-diameter ratios are used to carry out the uniaxial compression experiment on a servo-controlled testing machine.Based on the experimental results,the effect of size on the deformation failure and the energy properties of rock specimens is investigated.The results show that there is no distinct influence of specimen length on the axial deformation properties before peak stress,but the influence is remarkable after peak stress.Specimen length has small effect on the plastic deformation property after peak stress.Filure modes of nrock specimens change from simple to complex with the decrease of the sample lengths.With the increase of length-to-diameter ratio,the failure strain energy of specimens will decrease in accordance with an exponential equation and converge to a constant after the length-to-diameter ratio increases to 2.The failure energy variation is not monotonic as the length-to-diameter ratis increases.