摘要
玄武岩纤维复合材料(BFRP)锚杆逐渐应用于锚固工程,为研究BFRP锚杆锚固节理岩体剪切特性,采用室内直剪试验对比分析BFRP筋和传统钢筋锚固节理岩体抗剪性能,包括剪切强度-位移曲线、抗剪强度、锚杆失效特征和锚杆内力变化等特性,同时考虑粗糙度、锚固倾角、法向强度等因素影响。结果表明,BFRP锚杆较钢筋锚杆相比弹性段剪切刚度低,峰值剪切位移较大,但残余剪切强度较高;BFRP筋锚固剪切峰值前吸收的能量更多,吸收总能量与钢筋大致相同,剪切过程中同样表现出韧性。BFRP筋锚固节理岩体抗剪强度受锚固倾斜角度的影响较大,垂直锚固时锚固抗剪强度较低,锚固倾角减少为60°以下时则能发挥出相对钢筋更高锚固抗剪强度。BFRP锚固节理岩体剪切失效特征主要分为:树脂基质断裂;树脂基质和纤维均被剪断裂;树脂基质和周围岩体断裂。BFRP筋失效时无明显塑性屈服现象,树脂基质往往在较小的剪切位移下断裂,而纤维能抵抗较大的节理面错动,提高法向应力对剪切强度的贡献量。通过应变监测数据定量分析锚固角度为60°时BFRP筋与钢筋的轴力和剪力对剪切强度贡献关系,相同剪切位移下BFRP锚杆轴向力增长更快,轴向力对剪切强度的贡献更大。
Basalt Fiber Reinforced Polymer(BFRP) is gradually used as bolts in underground engineering. In order to study the shear characteristics of jointed rocks reinforced with BFRP bars,laboratory shear tests were carried out to comparatively analyze the shear properties of bolted joint rocks with BFRP bars and steel bars,including shear strength-displacement curve,shear strength,bolt failure characteristics and internal force changes in the bolts,and the influence factors such as roughness,bolt inclination and normal strength were also considered. The results show that,compared with the steel bolts,the BFRP bolted specimens have a lower shear stiffness,a larger peak shear displacement and a higher residual shear strength. The BFRP bolted specimens absorb more energy before the shear peak than the steel bar bolted specimens,although both them absorb the same total energy and exhibit toughness in the shear process. The shear strength of the BFRP bar bolted joint rocks is greatly affected by the inclination angle with a lower shear strength when the inclination angle is equal to 90°. When the inclination angle is reduced to less than 60°,the BFRP bolted specimens have a higher shear strength than the steel bar bolted specimens. The shear failure characteristics of BFRP bolted joint rocks can be categorized as:resin matrix fracture,shearing of both resin matrix and fibers,and fracturing of resin matrix and surrounding rock. When the BFRP bars fail,there is no obvious plastic yield. The resin matrix frequently breaks under a small shear displacement,while the fiber is able to resist a large joint dislocation which improves the contribution of the normal stress to the shear strength. Based on the strain monitoring data,the contribution rates of the axial force and shear force from the BFRP bars and the steel bars to the shear strength were quantitatively analyzed at an inclination angle of 60°. It was found that,compared with the steel bars,the axial force of the BFRP bolts increases faster under the same shear displacem
作者
张书博
王长盛
王刚
吴学震
郑新
贺鹏
徐锋
ZHANG Shubo;WANG Changsheng;WANG Gang;WU Xuezhen;ZHENG Xin;HE Peng;XU Feng(College of Civil Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Shandong Universityof Science and Technology,Qingdao,Shandong 266590,China;College of Civil Engineering,FuzhouUniversity,Fuzhou,Fujian 350108,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2022年第4期712-724,共13页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金面上项目(52079077)
山东省自然科学基金青年项目(ZR202103070016)。
