矿用预应力钢棒力学性能试验研究_中国煤炭行业知识服务平台

矿用预应力钢棒力学性能试验研究

Title

Laboratory study on mechanical properties of mine pre-stressed steel bars
作者

吴拥政吴建星
Author

WU Yongzheng，WU Jianxing
单位

天地科技股份有限公司开采设计事业部煤炭科学研究总院开采设计研究分院
Organization

1.Mining and Designing Department，Tiandi Sciences & Technology Co.，Ltd.，Beijing ，China；2.Mining and Designing Department，China Coal Research Institute，Beijing ，China
摘要

预应力钢棒具有预紧力等级高、延伸率高、受力状态好等优点，越来越广泛地应用于煤矿巷道支护工程中。为了进一步探究矿用预应力钢棒材料力学性能，在实验室进行了矿用预应力钢棒拉伸试验、金相组织分析、冲击韧性测试、预应力损失试验、偏载试验、安装推进阻力试验及配套锁具性能试验。结果表明：直径20 mm矿用预应力钢棒拉伸时极限承载能力为422 kN，与直径20 mm牌号HRB335锚杆杆体相比，增幅达176%，断后伸长率平均为13.3%，为锚索断后伸长率的2.4倍，断后呈杯锥状断口；钢棒拉断前后冲击吸收功分别为46 J和23.3 J，材料组织结构为回火索氏体，晶粒度为9.5和8.5，属于超细晶粒度；受力长度为1 230 mm和1 500 mm时，预应力损失为38.37%，和36.74%，随着载荷的加大，预紧力损失率减小；受力长度的增加，钢棒预紧力损失率减小；偏载角度为5°、10°、15°、20°及25°时，极限承载能力降幅分别为18.3%、22.5%、26.4%、26.9%及27.5%；采用28 mm钻孔时，直径18 mm和直径20 mm钢棒平均最大推进阻力分别为179 N和453 N，两者相差274 N，但两者推进均比较容易；预应力钢棒锚具平均承载能力为398.2 kN，锚环与夹片的洛氏硬度分别为27.78和58.39，能够满足国标和钢棒材料力学性能要求。
Abstract

With the advantages of high pretension， high elongation and good bearing capability， the pre-stressed steel bars have been more and more widely used in roadway support engineering of coal mines.In order to further explore the mechanical properties of pre-stressed steel bars used in coal mine， tensile tests， metallographic analysis， impact toughness test， pre-stress loss test， eccentric load test， installation resistance test and performance of matching locks of pre-stressed steel bar were carried out in the laboratory.The results show that the ultimate load-bearing capacity of 20 mm diameter pre-stressed steel bar is 422 kN，which is an increase of 176% compared to the 20 mm diameter HRB335 anchor bar， and the average elongation after breaking is 13.3%，which is 2.4 times of the anchor cable， and the cup-cone fracture formed after steel bar breaks.The impact absorption energy before and after breaking of the steel bar is 46.0 J and 23.3 J respectively；the structure of the material is tempered sorbite， and the grain size is 9.5 and 8.5， which belongs to ultra-fine grain size.When the bearing force length is 1 230 mm and 1 500 mm，the pre-stress loss is 38.37%，and 36.74%.As the load increases，the preload loss rate decreases；As the steel bar increases，the preload loss rate of the steel rod decreases； When the eccentric load angles are 5°， 10°， 15°， 20°， and 25°， the ultimate bearing capacity decreases are 18.3%，22.5%，26.4%，26.9%，and 27.5%；When drilling in 28 mm，the average maximum propulsion resistances of steel rods with diameters of 18 mm and 20 mm are 179 N and 453 N， respectively.The difference is 274 N，but both are easier to advance.The average carrying capacity of the pre-stressed steel bar anchorage is 398.2 kN， and the Rockwell hardness of the anchor ring and clamp are 27.78 and 58.39 respectively，which meets the requirements of national standard and mechanical properties of steel bar materials.
关键词

矿用钢棒预应力损失偏载试验安装推进阻力
KeyWords

steel bars used in coal mine；pre-stress loss；eccentric load test；installation resistance
基金项目(Foundation)

国家重点研发计划资助项目（2017YFC0804205）；天地科技创新基金资助面上资助项目（2019-TD-MS0030）
相关专题

这篇文章属于煤炭行业青年科学家论坛（2020年）（29篇）