基于黏聚力模型的螺纹钢锚杆拉拔数值模拟

Numerical Simulation of ribbed steel rebar bolts pull-out based on cohesive model

为研究螺纹钢锚杆锚固结构变形破坏机理,采用ABAQUS软件建立锚固结构轴对称数值模型,基于黏聚力模型,开展数值试验,获得锚固结构拉拔过程中锚杆变形、荷载以及锚固体位移场分布演化规律。试验结果表明:在相同的拉拔位移下,小肋间距锚杆也能够承受更高的拉拔荷载,表明小肋间距锚杆对巷道围岩变形的承载能力更强;在锚杆拉拔过程中,随着拉拔位移的增加,岩体破坏和离层区域呈倒碗形向岩体深部扩散,当拉拔位移增加至9.06 mm后,岩体锚固段末端处位移增速加大,岩体的最大位移为4.79 mm,出现在锚固段端口处,最终导致锚固段基体破坏;锚杆轴力与锚杆肋间距呈负相关,锚杆的轴力随着肋间距的减小而增加。

In order to study the deformation and failure mechanism of ribbed steel rebar bolts anchorage structure,the axisymmetric numerical model of anchorage structure was established by ABAQUS software.Based on the cohesion model,the numerical test was carried out to obtain the distribution and evolution law of bolt deformation,load and anchorage body displacement field during the pull-out process of anchorage structure.The test results show that under the same pull-out displacement,the small rib spacing bolt can also bear higher pull-out load,which indicates that the small rib spacing bolt has stronger bearing capacity for the deformation of surrounding rock of roadway.In the pull-out process of bolt,with the increase of pull-out displacement,the rock mass failure and separation area spread to the deep rock mass in an inverted bowl shape.When the pull-out displacement increases to 9.06 mm,the displacement growth rate at the end of the anchorage section of the rock mass increases,and the maximum displacement of the rock mass is 4.79 mm,which appears at the end of the anchorage section,eventually leading to the failure of the anchorage section matrix.The axial force of the bolt is negatively correlated with the rib spacing of the bolt,and the axial force of the bolt increases with the decrease of the rib spacing.