裂隙网络扩展机制试验研究

Experimental Study on the Rock Extension Mechanism of the Crack Network

在外部荷载作用下,岩体内部裂隙的形状是影响其强度和稳定性的重要因素之一。为了探究裂隙对岩石力学特性及破坏特征的影响,利用3D打印技术,制备间隙性离散裂隙网络模型,结合数字图像相关技术对裂隙网络类岩石模型试件在单轴压缩条件下的破坏特征进行研究。研究表明:因裂隙的存在,类岩石试件的弹性模量和峰值应力均随之发生显著降低;裂隙网络类岩石试件变形破坏过程中应力-应变曲线大致可划分为微缺陷闭合、线弹性、裂纹萌生与扩展、峰后应变软化4个阶段;基于试件应变场角度,从细观层次分析了裂隙网络分布对扩展路径选择以及局部应变化带演化的影响。该研究可为室内开展复杂裂隙扩展机理提供参考。

Under the action of external loads,the shape and layout of the internal fractures in a rock mass is one of the important factors affecting its strength and stability.In order to explore the impact of fractures on rock mechanics characteristics and failure characteristics,3D printing technology was used to prepare interstitial discrete fracture network models,and digital image related technologies were used to study the failure characteristics of fracture network rock model specimens under uniaxial compression.The study shows that the elastic modulus and peak stress of rock specimens are significantly reduced due to the existence of cracks;the stress-strain curve during the deformation and failure process of fracture network-like rock specimens can be roughly divided into micro-defect closure,linear elasticity,crack initiation and propagation,and post-peak strain softening;based on the strain field of the specimen,the influence of the fracture network distribution on the selection of the propagation path and the evolution of the local strain zone is analyzed from the perspective of the specimen strain field.This study can provide a reference for developing the complex crack propagation mechanisms indoors.