冲击载荷作用下预应力锚杆锚固阻裂效应试验研究  

Experimental study on anchoring crack-resistance effects of prestressed anchor under impact loads

作　　者：祖国利 王俊[1,2] 宁建国 蒲志强[2] 闫立恒 任志伟 胡浩 ZU Guoli;WANG Jun;NING Jianguo;PU Zhiqiang;YAN Liheng;REN Zhiwei;HU Hao(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Shandong Energy Group XIBEI Mining Co.,Xi'an 710018,China;Shandong Energy ZIBO Mining Group Co.,Zibo 255000,China;Anhui University of Science and Technology,Huainan 232000,China)

机构地区：[1]山东科技大学能源与矿业工程学院,山东青岛266590 [2]山东能源集团西北矿业有限公司,陕西西安710018 [3]山东能源淄博矿业集团责任有限公司,山东淄博255000 [4]安徽理工大学,安徽淮南232000

出　　处：《岩土工程学报》2023年第8期1743-1753,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52074170,51904163);深部煤矿采动响应与灾害预防国家重点实验室开放基金项目(SKLMRDPC21KF05)。

摘　　要：在采动应力、冲击动载作用下,深部巷道围岩原生裂隙进行发育、扩展、失稳是深部围岩动力灾害的重要诱因,通过锚杆支护增加破碎围岩完整性,抑制原生裂隙的再度扩展是预防围岩动力灾害的重要手段。为此,采用分离式霍普金森压杆试验系统开展端锚、全锚、让压+端锚3种锚固方式及端头锚固不同预紧力矩条件下预应力锚杆CCNBD试件的冲击动载试验,分析了预应力锚杆对岩体动态断裂韧性、裂纹起裂时间、裂纹扩展速度的影响规律,揭示冲击载荷作用下预应力锚杆锚固阻裂效应。研究结果表明:(1)预应力锚杆阻裂效应表现为提高岩体动态断裂韧性、延缓裂纹起裂时间与降低裂纹扩展速度;(2)高预紧力端头锚固与全长锚固均有助于锚杆发挥锚固阻裂效应,其强化顺序依次为全长锚固>端头锚固>让压+端头锚固,后者因让压结构补偿了裂纹扩展空间,弱化了锚固阻裂效应;(3)冲击载荷作用下加锚岩体变形破坏过程具有裂纹孕育阶段、裂纹扩展阶段、锚杆承载阶段3个阶段,高预紧力矩与全长锚固时锚杆轴向应力在裂纹扩展阶段增速最明显,锚杆锚固阻裂效应最明显。研究成果对深部动载巷道锚固支护工程具有一定的理论指导及借鉴意义。Under the action of mining stresses and impact dynamic loads,the development,expansion and instability of the primary fissures in the surrounding rock of deep roadways are an important cause for the dynamic disasters of the deep surrounding rock,and increasing the integrity of broken surrounding rock and inhibiting the re-expansion of the primary fissures by using the anchor supports are an important method to prevent the dynamic disasters in the surrounding rock.To this end,the impact dynamic load tests are performed on CCNBD specimens of prestressing anchor under different preloading moments of end anchor,and three anchoring methods of end anchor,full anchor and yield pressure+end anchor are adopted using the split Hopkinson pressure bar test system.The effects of various factors on the dynamic fracture toughness,crack initiation time and crack expansion rate of the anchored rock mass are analyzed to reveal the crack-resistance effects of the prestressed anchors under impact loads.The results show that:(1)The crack-resistance effects of the prestressed anchors improve the macro-dynamic fracture toughness of the anchored rock mass and delay the micro-crack initiation time and reduce the expansion rate.(2)Both the high preloading end anchorage and the full-length anchorage help anchors develop the crack-resistance effects.Their strengthening order is full-length anchorage>end anchorage>yield pressure+end anchorage.The third method weakens the crack-resistance effects because the yield pressure structures compensates for the crack expansion space.(3)The deformation and damage process of anchored rock mass under impact loads has three stages:crack breeding stage,crack expansion stage and anchor bearing stage.The axial stress of the anchor rod with high preloading moment and full-length anchoring has the most apparent growth rate in the crack expansion stage,and the crack-resistance effects are the most obvious.The research results have some theoretical guidance and reference significance for the anchorage support p

关 键 词：冲击载荷 预紧力 锚固方式 动态断裂韧性 阻裂效应 

分 类 号：TU456[建筑科学—岩土工程]