螺纹钢锚杆锚固岩石拉拔试验过程精细化数值模拟研究

Study on fine numerical simulation of pull-out test process of anchor rock with rebar anchor

为研究螺纹钢锚杆拉拔界面力学特性及锚固结构拉拔破坏过程,在锚杆拉伸试验及数值模拟的基础上,采用有限元软件ABAQUS建立螺纹钢锚杆拉拔对称平面模型,基于界面黏结损伤模型,对螺纹钢锚杆拉拔失效全过程进行模拟。结果表明:数值模拟可还原真实螺纹钢锚杆的拉伸断裂过程,与圆钢材料拉伸断裂特征不同,螺纹钢锚杆拉伸断裂方位与肋倾角平行;不同肋间距锚杆的载荷-位移曲线说明,肋间距越小,锚固承载性能越好;锚杆横肋的存在可提高黏结接触面积,增大机械咬合力;随着拉拔载荷增加,岩体呈漏斗状由锚固前端向锚固后端逐渐破坏,界面损伤及剪应力峰值逐渐向锚固段深部移动;锚杆、岩体及界面损伤会造成锚杆拉拔载荷-位移曲线波动,损伤越剧烈,波动越明显。

In order to study the drawing interface mechanical properties of threaded steel bolt and the drawing failure process of anchor structure,on the basis of bolt tensile test and numerical simulation,the symmetrical plane model of threaded steel bolt anchorage is established by using finite element software ABAQUS.Based on the interface bond damage model,the whole process of drawing failure of threaded steel bolt is numerically simulated.The results show that:the numerical simulation can restore the tensile fracture process of the real bolt.Different from the tensile fracture characteristics of round steel,the tensile fracture orientation of the bolt is parallel to the inclination angle of the rib;the variation law of load displacement curves of bolts with different rib spacings show that the smaller the rib spacing of bolts,the better the anchorage bearing performance,and the existence of bolt transverse rib can not only improve the bonding contact area,but also increase the mechanical biting force;with the increase of the pull-out load,the rock mass gradually fails from the front end to the back end in a funnel-like manner,and the interface damage and shear stress peak gradually move to the deep part of the anchorage.The damage of bolt,rock mass or interface will cause the fluctuation of load-displacement curve of bolt.The more severe the damage is,the more obvious the fluctuation of load displacement curve is.