含裂隙类岩石试样单轴抗压强度特征及裂纹演化规律

通过研究含复杂裂隙岩体性质，甄别岩体中关键裂隙，进而简化裂隙网络.基于3D打印技术制备含裂隙类岩石试样，利用数字图像相关(DIC)技术和颗粒流软件PFC研究了试样应变场变化、试样内局部应力分布状态和破裂模式.研究结果表明:1)相较于完整试样，含水平裂隙试样的峰值强度降低了20.9%，含垂直裂隙试样的峰值强度仅降低3%左右，水平裂隙对试样的劣化效果更显著;2)水平裂隙中部拉应力远超垂直裂隙端部应力，因此含水平裂隙试样更易且更早产生拉伸裂纹，导致含水平裂隙试样强度低于含垂直裂隙试样强度;3)当十字交叉裂隙中垂直裂隙长度为水平裂隙长度的1~2倍时，十字交叉裂隙中的水平裂隙是控制试样裂纹演化及强度特征的关键裂隙，因此十字交叉裂隙可简化为水平裂隙.

Uniaxial Compressive Strength Characteristics and Crack Evolution Laws of Rock-Like Samples with Flaws

The fracture network was simplified by studying the properties of rock mass with complex fractures and identifying key fractures in rock mass. Based on 3D printing technology， rock-like samples with different flaws were respectively made. The digital image correlation(DIC)technology was used to monitor the strain field in the sample during loading. The particle flow code(PFC)was used to study the local stress distribution and failure mode in the samples. The main research results show that: 1) Compared with the intact sample， the peak strength of sample with horizontal flaws is reduced by 20.9%， and the peak strength of sample with vertical flaws is only reduced by about 3%. The degradation effect of horizontal flaws on the sample is more significant. 2) The tensile stress in the middle of the horizontal flaw is far greater than that in the end of the vertical flaw， so it is easier and earlier for the sample with horizontal flaw to produce tensile cracks， resulting in that the strength of the sample with horizontal flaw is lower than the sample with vertical flaw under the condition of equal flaw length. 3)When the length of vertical flaw in cross flaws is 1~2 times of the horizontal flaw length， the horizontal flaw in cross flaws is the key flaw to control the crack evolution and strength characteristics of samples， and the change of vertical flaw length has no significant effect on the crack evolution and strength characteristics of samples. Therefore， the cross flaws can be simplified as a horizontal flaw.