锚杆-围岩结构的耦合振动和减振

Coupling vibration and vibration reduction of anchorsurrounding rock structure

锚杆支护是隧道施工中常见的支护手段,而随着施工工况日趋复杂,锚杆与围岩的组合结构也承受着各类动力荷载的影响。针对隧道中单根锚杆的受力特性有较多研究,而对于锚杆和围岩组合体的动力特性研究较少。对锚杆-围岩结构进行整体分析,简化出一种巷道顶板锚杆支护模型,结合动力学双梁理论,建立并求解出模型动力学方程;运用MATLAB软件进行数值模拟,研究不同支护参数下结构的自振特性以及在外荷载作用下的动力响应,提出减振措施;利用有限元软件GTS NX建立二维模型,验证支护体系的安全性。结果表明:锚杆-围岩结构的动力特性与锚固段长度、锚杆间距和锚杆直径有关。在所建模型中,随着锚固段长度与锚杆间距的适当增加,结构动力响应明显减弱;随着锚杆直径的变化,结构动力特性的变化情况较复杂,结构不同部位的动力响应变化趋势差别较大。

Bolt support is a common means in tunnel construction,and with the increasing working condition complexity,the combined structure of bolt and surrounding rock is also subjected to various dynamic loadings.In the past,researches focused on the mechanical characteristics of single bolt in tunnel,but there are few on the dynamic characteristics of the combination of bolt and surrounding rock.In this paper,the overall analysis of the bolt-surrounding rock structure,with a simplified roadway roof bolt-supporting model,combined with the dynamic double beam theory,was established to solve the dynamic model equation;MATLAB was used for numerical simulation to study the natural vibration characteristics of the structure under different supporting parameters and the dynamic response under the external load,and the vibration reduction measures were proposed.Finally,GTS NX is used to verify the safety of the supporting system.The results show that the dynamic characteristics of rock bolt-surrounding rock structure are related to the length of anchor segment,the distance between bolts and the diameter of bolts.In the model established in this paper,the dynamic response of the structure decreases obviously with the proper increase of anchorage length and bolt spacing.With change of bolt diameter,the dynamic characteristics of the structure are becoming complicated,and the dynamic response of different parts of the structure varies greatly.