冲击动载下含孔洞岩石的力学特性及破裂机制  

Mechanical Properties and Fracture Mechanism of Pre-holed Rock under Impact Load

作　　者：吴浩 凡奥奇 贾永胜 王孟来[3] 李树建 张斌 WU Hao;FAN Ao-qi;JIA Yong-sheng;WANG Meng-lai;LI Shu-jian;ZHANG Bin(Hubei Key Laboratory of Blasting Engineering,Jianghan University,Wuhan 430056,China;School of Mines,China University of Mining and Technology,Xuzhou 221116,China;National Engineering and Technology Center for Development&Utilization of Phosphorus Resources,Yunnan Phosphate Chemical Group Co.,Ltd.,Kunming 650600,China)

机构地区：[1]江汉大学爆破工程湖北省重点实验室,武汉430056 [2]中国矿业大学矿业工程学院,徐州221116 [3]云南磷化集团有限公司国家磷资源开发利用工程技术研究中心,昆明650600

出　　处：《爆破》2023年第4期1-12,共12页Blasting

基　　金：国家自然科学基金(52204160);江苏省自然科学基金(BK20210515);中国博士后科学基金(2022MD713814,2023T160555);爆破工程湖北省重点实验室开放基金(BL2021-10);国家重点研发计划项目(2022YFC2905600)。

摘　　要：硬岩矿山巷道在机械冲击凿岩和炸药爆破的动力扰动作用下极易发生冒顶片帮和岩爆等动力灾害,研究巷道变形破坏机理的动载效应意义重大。为了弄清动力扰动下巷道围岩的力学行为,将硬岩巷道简化为岩石力学孔口问题,采用50 mm杆径的改进型霍普金森压杆实验系统对系列含孔洞板状砂岩进行了冲击加载实验,探索孔洞尺寸和形状对岩石动态力学参数、破坏模式及能量耗散特征的影响。研究结果表明:孔洞的存在对岩石的动态强度、动态弹性模量和峰值应变均具有显著的弱化作用。随着孔洞尺寸的增大,岩石动态力学特性参数显著降低;不同孔洞形状中,方形孔洞试样的动态强度和峰值应变最大,紧接着是马蹄形孔洞和圆形孔洞试样,而它们的弹性模量大小呈现相反的结论。岩石破坏形态方面,冲击作用下完整岩石和孔洞岩石分别发生劈裂拉伸破坏和拉剪破坏。另外,马蹄形孔洞试样能耗密度和分形维数同比最大,分别为1.94 J/cm^(3)和2.11 J/cm^(3),表明其破坏过程最为剧烈,而圆形和方形孔洞试样的破碎块度相差不大。该研究成果科学揭示了硬岩巷道围岩破裂特征,为硬岩巷道支护设计和岩石灾变防治奠定了重要理论基础。It is prone to occur dynamic disasters such as roof falling,sidewall slabbing and rock burst under dynamic disturbance of mechanical percussion drilling and explosive blasting in the roadway with hard rock.It is extremely meaningful to investigate the dynamic load effect on roadway deformation and failure mechanism.To understand the mechanical behavior of roadway surrounding rock under dynamic disturbance,a hard rock roadway was simplified as a hole in rock.And then,a series of impact tests were conducted on prismatic sandstone rock specimens with a hole by a modified split Hopkinson pressure bar testing system to explore the influence of hole size and shape on the dynamic mechanical properties,failure mode and energy dissipation characteristics.The results show that the existence of the hole has significant weakening effects on the dynamic strength,dynamic elastic modulus and peak strain.The dynamic mechanical properties of the rock decrease significantly with the increase of hole size.Among the specimens with different hole shapes,the dynamic strength and peak strain of the square-holed specimens are the largest,followed by the horseshoe-holed and the circle-holed specimens,but their elastic moduli show opposite results.In terms of rock failure modes,splitting tensile and tensile-shear failure occur respectively in intact specimens and pre-holed specimens under impact load.Additionally,the energy consumption density and fractal dimension of the horseshoe-holed specimens are the largest,which are 1.94 J/cm^(3)and 2.11 J/cm^(3),respectively.It indicates that the failure process is the most intense for the horseshoe-holed specimens,while the fragmentation degree of the circle and square holed specimens is not much different.

关 键 词：冲击加载 含孔洞岩石 动态力学特性 破坏模式 能量耗散 分形维数 

分 类 号：O383[理学—流体力学] TD803[理学—力学]