预制裂隙类岩石试件表面变形场演化与裂隙扩展机理研究  

Surface deformation field and fracture propagation mechanism of rock-like specimen with pre-existing fracture

作　　者：王兆会[1,2] 孙文超 王雪冰 乔博锴 WANG Zhaohui;SUN Wenchao;WANG Xuebing;QIAO Bokai(School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Top-coal Caving Mining Research of Coal Mining Industry,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)能源与矿业学院,北京100083 [2]放顶煤开采煤炭行业工程研究中心,北京100083

出　　处：《煤炭科学技术》2023年第10期72-82,共11页Coal Science and Technology

基　　金：国家自然科学基金资助项目(51934008,51904304);中央高校基本科研业务费资助项目(2023ZKPYNY01)。

摘　　要：我国东部矿区相继进入深部开采阶段,裂隙发育程度升高,开采扰动效应增强,围岩控制难度增大。为研究含裂隙岩石破坏机理,提高深部围岩控制效果,采用单轴抗压试验结合DIC技术研究了裂隙倾角对类岩石试件力学特性、表面变形场、裂隙扩展路径的影响。结果表明:预制裂隙与翼裂纹产生剪切互锁效应,含裂隙岩石应力-应变曲线呈双峰形态;裂隙倾角增大,岩石弹性模量和损伤程度升高,单轴抗压强度先降低后升高;确定了单轴抗压强度与裂隙倾角的定量关系,定义了含裂隙岩石破坏优势倾角,张开型裂隙优势倾角为45°;含裂隙岩石变形局部化现象始现于裂隙尖端,拉应力主导型启动应力为初始屈服强度的80%,剪应力主导型降至60%;变形集中带扩展路径与表面裂隙一致,应变值达到5.0%时,岩石变形由局部集中向裂隙发育阶段过渡;预制裂隙倾角为60°和75°时,岩石发生拉剪混合破坏,其他角度发生拉伸破坏;拉伸裂隙孕育时间长,两侧特征点水平位移曲线相互分离,剪切裂隙孕育时间短,两侧特征点纵向位移曲线相互分离;构建了预制裂隙类岩石试件GBM模型,岩石内部微裂纹以拉伸型为主,剪切型微裂纹随预制裂隙倾角增大呈先增多后减少趋势;DIC技术可预判岩石起裂位置、时间和裂隙扩展路径,为深部岩石破坏防控提供前兆信息。Eastern coalfield goes into deep mining gradually in China.Fracture development rises greatly in surrounding rocks,increasing the difficulty in ground control under increased mining disturbance.In order to reveal failure mechanism of fractured rocks and improve ground control of deep coal mine,the influence of fracture angle on mechanical behavior,surface strain field and fracture propagation is analyzed by using uniaxial compression test combined with DIC technique.The results show that stress-strain curve of rock specimen with pre-existing fracture presents double-peak shape,induced by shear inter-locking effect between pre-existing and newly-developed fractures.With the growth in fracture angle,elastic modulus and damage degree rise in rock specimen while uniaxial compressive strength(UCS)experiences decreasing and subsequent increasing stages,respectively.Quantitative relationship between the UCS and fracture angle is deduced.Preponderant dip angle is defined for failure of rock with pre-existing fractures and the value is 45°when the fracture belongs to open-type.Deformation localization rock with pre-existing fractures occurs at the fracture tip.The initiation stress reaches 80%of initial yield stress when localization area is dominated by tensile stress,and the percentage decreases to 60%when dominated by shear stress.Propagation path of deformation localization area is consistent with that of surface fracture.Rock deformation stage transits from strain localization to fracture development when strain magnitude reaches 5.0%.Rock specimen fails in tension and shear mixed mode when fracture angle is 60°or 75°.Otherwise,only tension failure is observed in the loading process.It takes longer to form a tensile fracture and horizontal displacement curves of feature points on two sides deviate from each other.It takes shorter to form a shear fracture and vertical displacement curves show deviation trend.Grain based model(GBM)is developed for fractured specimen,which indicates small crack development is dominat

关 键 词：预制裂隙 DIC技术 表面应变场 应变局部化 裂隙扩展 

分 类 号：TD313[矿业工程—矿井建设]