锚固节理直剪力学行为的颗粒流数值分析

NUMERICAL ANALYSIS FOR DIRECT SHEAR TEST OF BOLTED JOINT BASED ON PARTICLE FLOW CODE

为探究锚固节理在直剪加载作用下的细观力学响应,利用颗粒流数值计算方法建立不同锚固角度下的锚固节理数值模型,并进行不同法向荷载下的直剪试验。之后,通过分析和对比剪切-位移曲线和峰值剪切强度来对锚固节理宏观力学性质进行研究。与此同时,基于微裂纹分布规律,从细观角度揭示了剪切荷载下不同锚固角度的岩石节理面的破坏特征;研究结果显示。(1)不同于非锚固节理,锚固节理的剪切-位移曲线在剪切后期呈现出一定的增长趋势,且粗糙度不同曲线变化特征存在一定的差异。(2)不同锚固角度下,锚固节理的破坏模式存在着较为明显的差异。当锚固角为90°时,锚固节理模型的破坏主要集中于锚杆与上下节理面接触位置,且破坏主要为挤压式破坏。随着锚固角度的减小,接触位置的破碎区域不断减小,节理破坏主要表现为沿着锚杆的轴向拉伸变形破坏及内部的拉伸破坏。(3)锚固角度的变化对锚固节理的抗强度的影响程度与节理面的粗糙度存在一定关联。具体而言,较为平直节理抗剪强度随着锚固角度的增大,增长趋势明显,而粗糙节理面随着锚固角度的增大峰值抗剪强度的变化趋势相对较为平缓。

This paper investigates the micro-mechanical response of supported joint under direct shear loading with the particle flow code.It builts the supported joint and unsupported joint numerical model successfully.It investigates the mechanical properties and failure mode of supported joint under direct shear tests and under different normal stresses.At the same time,based on the shear-displacement curve and peak shear strength of the numerical model,it investigates the macro-mechanical properties.Moreover,the failure characteristics of the bolted joint are also analyzed via the micro-cracks distribution.Detailed results are given as follows:(1)Compared to theunsupported joint,the shear stress curve of the supported joint shows obvious increasing trend at the post-peak phase.There is obvious difference between the shear stresses for unsupported and supported joints.(2)Due to the different inclination angles,the supported joint exhibits different failure modes.When the inclination angle equals to90°,the failure of the joint concentrates at the contact point of the joint and bolt.While,with increases of the inclination angle,the failure of the joint gradually turns to tensile failure along the bolt and the tensile crack propagation in the rock.(3)With different joint roughness value,the influence of bolt angel on the shear strength is different.When JRC value is small,the bolt shown a great influence on the peak shear stress,but when the JRC is larger,the influence is weaken.