动力扰动下高承载锚杆锚固结构的力学响应及失效机理研究

In the deep rock mass engineering, the rockbolt anchorage structure are in high stress condition when there is deformation in the surrounding rock. In addition, the dynamic loadings such as blasting vibration make the rockbolt anchorage structure quite easy to support failure, resulting in the instability of anchorage cavity. Focusing on the feature, the single and cyclic impact tests on different surrounding rock and anchoring conditions will be conducted on the bolts subjected to high bearing capacity based on the new device has been designed. The slippage of the bolt shank, the axial stress loss, failure modes of surrounding rock and grout, disbanding characteristics at anchorage interfaces, and the propagation of the stress waves in the bolt will be investigated. The effect of impact energy levels and times on the dynamic performance of rockbolt anchorage structure will be studied. The axial stress distribution law under dynamic loading will be investigated. The shear stress distribution at the grout-surrounding rock interface will be studied by combining the stress wave theory and numerical simulation. The load transfer mechanism at the anchorage interfaces under dynamic loads will be revealed. The damage properties and the damage evolution law of rockbolt anchorage structure will be investigated, and the quantitative contribution of dynamic disturbance to the failure of rockbolt anchorage structure will be obtained. The failure mechanism of the highly loaded rockbolt anchorage structure will be revealed. This project will provide a scientific theory basis for the design and construction of rockbolt supporting in the deep rock mass engineering.

深部岩体工程中，锚杆锚固结构在围岩体变形后处于高承载应力状态，爆破振动等动载荷扰动后极易诱发支护失效，进而造成锚固硐室失稳等灾害。项目以此为背景，利用自主研发的锚杆冲击试验装置，开展不同围岩条件和锚固方式下高承载应力状态锚杆的单次和循环冲击试验，分析冲击载荷下锚杆滑移量、轴力损失量、锚固剂和围岩的破坏特征、锚固界面的脱粘特征以及锚杆中的应力波传播规律，研究冲击能级和次数等对锚杆力学行为的影响；分析动载作用下锚杆的轴向应力分布规律，结合应力波理论和数值模拟，研究锚固剂-围岩界面的剪切应力分布特征，揭示动载作用下锚固界面应力传递机理；研究锚杆锚固结构的动态损伤特性及损伤演化规律，获得动力扰动对高承载锚杆锚固结构失效的定量贡献，进而揭示动力扰动下高承载锚杆锚固结构失效机理，为深部岩体工程锚杆支护设计与施工提供理论依据。

深部岩体工程中，锚杆锚固结构在围岩体变形后处于高承载应力状态，爆破振动等动载荷扰动后极易诱发支护失效，进而造成锚固硐室失稳等灾害。项目以此为背景，采用室内试验、理论分析和数值模拟相结合的方法，系统研究了动力扰动下高承载锚杆锚固结构的力学响应及失效机理，取得的主要成果如下：(1) 完成了多次动力扰动下锚固岩石力学响应特征研究，获得了动态拉剪作用下锚固岩石的承载能力、裂纹演化规律、破坏特征、声发射特征及锚杆失效形式，揭示了锚杆的加固作用机制。(2) 基于改进后的SHPB试验平台，自主设计了锚杆动态拉伸试验系统，完成了不同应力条件和锚固方式下锚杆锚固结构的单次和多次冲击试验，发现了锚杆中应力波的波峰值在锚固段随传播距离的增加而逐渐减小的规律，获得了锚杆杆体不同位置处应力波峰值应变与冲击次数、预应力的变化规律，揭示了多次动力扰动作用下锚固界面损伤演化机制。(3) 得到了不同预应力下锚固界面完全脱粘时冲击能级与冲击次数的规律，发现了锚杆的滑移量随冲击次数的增加而呈指数增长的变化规律，获得了多次动力扰动作用下锚杆轴力损失演化过程及作用机制，揭示了多次动力扰动作用下高应力工程围岩锚杆锚固结构失效演化机理。