摘要
This study investigates the shear mechanical responses and debonding failure mechanisms of anchoring systems comprising three anisotropic media and two anisotropic interfaces under controlled boundary conditions of constant normal load(F_(s)),constant normal stiffness(K),and shear rate(v).A systematic analysis of shear mechanical properties,the evolution of maximum principal strain field,and damage characteristics along shear failure surface is presented.Results from direct shear tests demonstrate that initial shear slip diminishes with increasing F_(s)and K,attributed to the normal constraint strengthening effect,while an increase in v enhances initial shear slip due to attenuated deformation coordination and stress transfer.As F_(s)increases from 7.5 to 120 kN,K from 0 to 12 MPa/mm,and v from 0.1 to 2 mm/min,the peak shear load increases by 210.32%and 80.16%with rising F_(s)and K,respectively,while decreases by 38.57%with increasing v.Correspondingly,the shear modulus exhibits,respectively,a 135.29%and 177.06%increase with rising F_(s)and K,and a 37.03%decrease with larger v.Initial shear dilation is identified as marking the formation of shear failure surface along anisotropic interfaces,resulting from the combined shear actions at the resin bolt interface,where resin undergoes shear by bolt surface protrusions,and the resin-rock interface,where mutual shear occurs between resin and rock.With increasing F_(s)and K and decreasing v,the location of the shear failure surface shifts from the resin-rock interface to the resin-bolt interface,accompanied by a transition in failure mode from tensile rupture of resin to shear off at the resin surface.
锚固技术因其优越的支护强度、便捷的安装过程、高适应性和经济性,在采矿、隧道和边坡等岩土工程领域得到了广泛的应用。锚固系统的承载能力和长期稳定性受到诸多因素影响,其中服役期间异性介质之间的界面剪切力学响应尤为关键,但迄今为止研究较少。本文首先建立了含三种异性介质和两种异性界面的锚固系统等效剪切力学模型,开展室内直剪试验,揭示了不同边界条件下,即恒定法向载荷(CNL)、恒定法向刚度(CNS)和剪切速率(v),锚杆-树脂-岩石锚固系统的剪切力学特性和脱粘失效机理。结果表明,随着法向载荷F_(s)和法向刚度K的增加,异性界面的初始剪切滑移明显减小,而随着剪切速率v的增加,初始剪切滑移显著增大。当F_(s)从7.5 kN增加到120 kN、K从0增加到12 MPa/mm以及v从0.1 mm/min增加到2 mm/min时,峰值抗剪强度分别随着F_(s)和K的增加而增大了210.32%和80.16%,而随着v的增加则减小了38.57%。初始剪胀标志着沿异性界面的剪切破坏面的形成,且随着F_(s)和K的增加,剪切破坏面的位置从树脂-岩石界面转移到树脂-锚杆界面,失效模式从树脂的拉伸破断转变为树脂表面由锚杆肋剪切形成的“月牙形”豁口。本文的研究成果为理解和优化锚固系统的界面抗剪特性提供了重要的理论依据,有助于提高锚固系统在实际工程应用中的长期稳定性。
基金
Projects(52174092,42472338,51904290)supported by the National Natural Science Foundation of China
Project(BK20220157)supported by the Natural Science Foundation of Jiangsu Province,China
Project(2022YCPY0202)supported by the Fundamental Research Funds for the Central Universities,China。
作者简介
Corresponding author:YIN Qian,PhD,Professor,E-mail:Jeryin@foxmail.com,ORCID:https://orcid.org/0000-0001-5161-3761;Corresponding author:TAO Zhi-gang,PhD,Professor,E-mail:taozhigang1981@163.com。
