横肋作用下左旋无纵筋预应力锚杆荷载传递及破坏规律

发布时间：2018-01-20 00:13

本文关键词： 预应力锚杆横肋锚固界面荷载传递破坏演化　出处：《河南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：目前我国煤矿所应用的锚杆杆体类型多为带横肋钢筋,以往在研究左旋无纵筋树脂锚杆荷载传递及破坏演化规律中,因试验条件所限杆体多被简化为圆钢,难以对横肋在荷载传递及破坏演化中的力学行为进行分析。本文基于剪切位移原理及ABAQUS数值模拟,对横肋作用下的左旋无纵筋预应力树脂锚杆的荷载传递及破坏规律进行研究,结果表明:(1)完全弹性条件下螺纹钢树脂锚杆的杆体-树脂界面剪切应力呈现“锯齿”状分布,剪切应力随锚固深度呈现周期性震荡衰减趋势。螺纹钢树脂-岩体界面剪应力分布与圆钢类似;锚固系统破坏前,横肋在荷载传递中对围岩锚固增强效果不明显。(2)拉拔条件下靠近拉拔端附近的横肋附近的树脂-杆体界面最先发生破坏,但裂纹发育范围内的局部树脂-杆体界面依然保持较大的剪切应力。螺纹钢较圆钢锚杆其极限拉拔强度大大提高的原因在于锚固系统局部界面出现破坏后横肋依然可向岩体传力,横肋的传力优势发挥在锚固系统破坏演化阶段。合理改善横肋几何参数能够改善树脂-杆体界面的应力分布、提高极限拉拔强度与残余强度。根据预应力锚杆-围岩相互作用特性,提出尾部缓凝全长预应力锚杆施工方法。提出预应力及托锚力的等效数值模拟方法,数值模拟结果表明,在锚固岩体纵向膨胀作用下,尾部缓凝锚固方式比一次全凝有着更好的锚固效果,对岩体纵向变形的响应更加敏感。
[Abstract]:At present, the type of bolt body used in coal mine in our country is mostly steel bar with transverse rib. In the past, in studying the law of load transfer and failure evolution of resin anchor rod with left longitudinal reinforcement, the limited bar body is simplified to round steel because of the test conditions. It is difficult to analyze the mechanical behavior of transverse ribs during load transfer and failure evolution. This paper is based on the principle of shear displacement and ABAQUS numerical simulation. The law of load transfer and failure of prestressed resin anchor rod with left longitudinal reinforcement under the action of transverse rib is studied. The results show that the shear stress at the interface between the resin and the rod is "sawtooth" under the fully elastic condition. The shear stress tends to decay periodically with the anchoring depth. The shear stress distribution at the interface of rebar resin and rock mass is similar to that of round steel. Before the Anchorage system failure, the reinforcement effect of transverse rib on surrounding rock is not obvious in load transfer.) under the condition of drawing, the interface between resin and bar near the transverse rib near the drawing end is first destroyed. However, the local resin-rod interface within the crack development area still maintains a large shear stress. The reason why the ultimate pull-out strength of the rebar is much higher than that of the round anchor is due to the transverse rib dependence after the failure of the local interface of the anchoring system. But it can transmit force to rock mass. The force transfer advantage of the transverse rib is played in the stage of the failure evolution of the Anchorage system. Reasonably improving the geometric parameters of the transverse rib can improve the stress distribution at the interface between the resin and the rod. According to the interaction between prestressed anchor rod and surrounding rock, the construction method of full-length prestressed anchor rod is put forward, and the equivalent numerical simulation method of prestressing force and anchor force is put forward. The numerical simulation results show that the tail retarding anchoring method has better anchoring effect and is more sensitive to the longitudinal deformation of the rock mass than that of the first full solidification under the action of longitudinal expansion of the anchored rock mass.
【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD353.6

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