注浆体配合比改善岩锚抗拔特性的试验研究  

EXPERIMENTAL STUDY ON MIXTURE RATIOS OF GROUTING MATERIAL FOR IMPROVEMENT OF PULL-OUT BEHAVIORS OF ROCK CABLES

作　　者：饶枭宇[1] 唐树名[2] 张永兴[1] 罗斌[2] 李剑[1] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆交通科研设计院,重庆400067

出　　处：《岩石力学与工程学报》2008年第2期390-396,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家杰出青年科学基金项目(50625824);交通部西部建设科技项目(200431874010)

摘　　要：注浆体配合比是预应力锚固体系优化设计的关键参数之一,对岩锚抗拔特性影响显著。当前,有关注浆体方面的研究还较少涉及,国内外的相关规范对这种专用注浆体也未制订统一的行业标准。因此,在广泛调研实体工程所使用的注浆体的情况下,设计11种不同配合比的注浆体,分别测试各自的物理力学性能,采用室内抗拔试验研究注浆体配合比对岩锚极限承载能力、荷载变位特性的影响。试验结果表明:注浆体中掺入适量的砂可以提高注浆体的断裂能,增强钢绞线与注浆体黏结界面的粗糙度以及对钢绞线解扭膨胀的约束,从而显著增强岩锚的极限承载强度,而降低注浆体的水灰比对提高岩锚的极限承载强度的效率较低;普通预应力锚索常见的破坏模式是钢绞线与注浆体的滑脱黏结破坏,建议在以后的锚固工程设计以及规范的修订时对此引起足够的重视。The influence of mixture ratio of grouting material on the pull-out behaviors of rock cable is obvious,which is one of key parameters for the optimal design of prestressed anchorage systems.Unfortunately,few studies are found about the influence of mixture ratio of grouting material on the pull-out behaviors of rock cable;and there are not sufficient or professional standards established for the special grouting material in prestressed anchorage specifications.Based on many investigations of in-situ projects,eleven cement-based grouting materials with different mixture ratios and related physico-mechanical characteristics are respectively tested;and the laboratory pull-out test has also been carried out to study the influence of mixture ratio of grouting material on the limit bearing capacity and load-displacement behaviors of rock cable.The results of pull-out tests show that mixing appropriate amount of sand into cement-based grouting material could increase the fracture energy,thus enhance the roughness of cementation interface between cable and grouting material,and increase the restraint of cable untwisting expansion.The limit bearing capacity of rock cable,consequently,is remarkably improved.However,it has less effect through decreasing the water-cement ratio to elevate the limit bearing capacity of rock cable.Debonding along the cable-grouting material interface is the dominant failure model of conventional prestressed cable bolt,so great importance should be attached to the failure model in the design of anchorage engineering and revision of technical specification for prestressed anchors in the future.

关 键 词：岩土工程 注浆体 配合比 岩锚 抗拔特性 

分 类 号：TU44[建筑科学—岩土工程] TV554.12[建筑科学—土工工程]