考虑横向抗剪效应的节理岩体全长黏结型锚杆锚固机制研究及进展

Research progress in bolting mechanism and theories of fully grouted bolts in jointed rock masses

全长黏结型锚杆在岩质边坡和洞室支护等领域有着广泛的工程研究背景,由于岩体的结构效应,全长黏结型锚杆除发挥轴向抗拉作用外,同时因不稳定岩体具有沿结构面发生滑动或滑动趋势而发挥横向抗剪效应。拉剪作用下,节理岩体锚杆与纯受拉荷载作用的锚杆在地质特征、力学机制、失效模式以及评价方法上存在本质的差别。近些年来,国内外相关学者针对节理岩体锚杆的力学与变形特征、岩石/浆体与锚杆的相互作用和锚杆破坏机制及模式等方面开展大量的试验研究与理论分析,以揭示与其地质力学特征相适应的锚固机制、建立相应的锚固理论体系和工程设计方法。本文从结构控制稳定的角度出发,系统地分析节理岩体锚固机制研究的工程背景和科学意义,探讨拉剪作用下节理锚杆的力学与变形演化规律,揭示基于岩石/浆体与锚杆相互作用的节理岩体内在锚固机制,对比分析节理岩体锚固弹性地基梁模型和结构力学模型的优缺点。在总结分析节理岩体锚固研究成果的基础之上,指出当前研究重点及存在的问题,提出节理岩体锚固理论与评价方法的研究方向,有望对完善节理岩体锚固理论体系及建立工程设计方法提供参考。

Fully grouted bolts are widely applied in rock slope and tunnel engineering. Due to the structural effect of rock masses,the sliding of the unstable block along the joint plane causes the combined action of axial and shear forces in the bolt. The bolting theory of jointed rock mass is essentially different from the pull rod model which takes the bolt as a pure tension element in many respects such as geological features,mechanical mechanism,failure mode and evaluating method. In the past decades,in order to reveal the bolting mechanism of fully grouted bolts in jointed rock mass and then to develop the bolting theory and design method,laboratory tests and theoretical analysis were performed with respect to the stress and deformation performance of jointed rock bolts,interaction between rock/grout and bolts,failure mechanism of bolts and theoretical approaches. From the viewpoint of rock structure controlling the stability,the engineering background and scientific interest of jointed rock bolting were presented,and the mechanical behavior and deformation response of jointed rock bolts due to the combined action of tension and shear were investigated in this paper. The bolting mechanism of fully grouted bolts in jointed rock masses was explored and comparisons between the elastic ground beam model and the structural mechanic model were carried out. Finally,on the basis of a detailed summary of existing researches,key problems and development tendency of bolting theory of jointed rock mass were pointed out. The work presented is to attempted to provide a reference for the understanding of bolting mechanism of jointed rock mass,the development of bolting theories and the practice of bolting engineering.