不同保载时间实验的花岗岩声发射特性研究
Study on the Acoustic Emission Characteristics of Granite in Different Holding Time
王强 1冯夏庭 1李元辉1
作者信息
- 1. 东北大学资源与土木工程学院,辽宁沈阳110819;深部金属矿山安全开采教育部重点实验室,辽宁沈阳110819
- 折叠
摘要
为了研究冲击地压发生前岩体处于加载或保载阶段,有突出倾向的岩体处于保载蠕变状态的问题,对花岗岩试件以每30 kN为梯度进行单轴不同时间保载实验,保载时间分别为1、3、5、10和15 min,并结合声发射进行实验研究.研究结果表明:①不同的保载时间对试件的强度及声发射参数有很大区别.与单轴直接加载相比,保载15 min的试件强度降低了43%;与单轴直接加载试件破坏点相比,保载15 min试件破坏时声发射撞击率提高了47%,保载15 min试件破坏时能量累积提高了53%;②不同保载时间,每提高相同加载梯度,保载时间越长试件的声发射撞击率越高;③花岗岩试件在实验过程中,保载时试件损坏或保载后刚加载试件便损坏的现象,说明保载阶段对试件的破坏有很大影响;④花岗岩在单轴保载压缩条件下,每个阶段产生的声发射具有不同的特征.因此,可以用花岗岩保载实验来研究岩石的微观损伤破坏,也可预测现场工程岩体的宏观断裂过程.
Abstract
In order to study situation that the rock mass is keeping loading or at loading stage before the rock burst oc-curs,the rock mass with prominent tendency is often in the state of loading creep. Uniaxial loading experiment of the granite specimens with a gradient of each 30 kN was carried out under different holding time of 1 min,3 min,5 min,10 min and 15 min,combining with experimental studies on acoustic emission. Research results showed that:(1)Different holding time on the strength and acoustic emission parameters have a great difference. Compared with uniaxial loading directly,the strength of the test specimen at 15 min is reduced by 43%;Compared with the failure point of uniaxial loading-directly specimen,the acoustic emission hit rate of specimen at holding 15 min is increased by 47%, and the energy accumulation at holding 15 min is in-creased by 53%;(2)In different holding time,and with the same loading gradient increasing,the longer the holding time,the higher the AE hit rate of specimens;(3)In the experimental process of granite specimen,there will the phenomenon of speci-men damage at loading or just after loading,so it indicates that loading is a great impact on specimen damage;(4)Under differ-ent uniaxial loading compression conditions,the acoustic emission of granite in each stage has different characteristics. There-fore,the granite loading experiment can be used to study the microscopic damage and failure of rock,and also to predict the macroscopic fracture process of rock mass.
关键词
花岗岩/保载实验/声发射/撞击率/累计能量Key words
Granite/Holding experiment/Acoustic emission/Impact rate/Cumulative energy引用本文复制引用
基金项目
国家自然科学基金(51674061)
中央高校基本科研业务费专项(N150104007)
出版年
2017
NETL
NSTL
维普
万方数据