摘要
研究超声波波速与受载煤体力学特性的关系对煤炭安全开采有重要意义。为明确受载煤体孔裂隙发育的力学变化规律与波速变化量的关系,以焦作古汉山矿山西组二1煤层原煤为研究对象,借助煤储层压裂模拟及物性特征试验系统,依据超声波技术对三轴加载煤体进行测试,计算波速变化量,然后用波速变化量分析受载煤体力学特性与煤体结构中孔、裂隙的联系,为煤炭安全开采提供力学依据。结果表明:1)在受载条件下,煤体会重复出现初始压密阶段、弹性阶段、屈服阶段,且在弹性阶段煤体压密程度最好,波速变化最快;2)煤体受力产生孔、裂隙对声波影响显著,弹性阶段煤体压密程度高,孔、裂隙发育程度小,波速变化量达到最大,到屈服阶段,煤体孔、裂隙发育程度高,波速变化量降低,变化明显;3)通过分析波速变化率得出受载煤体的变化程度,波速变化率大,表明煤体变化程度不明显,煤体孔、裂隙发育程度不高,反之亦然。
It is of great significance to study the relationship between the ultrasonic wave velocity and the mechanical properties of the loaded coal for safe steady coal mining. In order to define the relation between the variation of the wave velocity and the regularity of the mechanical development variation of the pores and fissures in the load coal samples,we have taken the coal sample from No. 2 – 1 coal seam of the western formation group in Guhanshan Coal Mine,Jiaozuo,under the triaxial-directional compression equipment and the ultrasound measuring instrument simultaneously. Based on the above said experimental results,we have made a measurement of the velocity change in the coal sample and analyzed the mechanical features of the loaded coalseam with the holes and cracks in the coal structure. So as to provide the mechanical basis for the coal mining safety. (1) Under the load conditions,it would be possible for the elastic stage and the new crack stage to come about repeatedly in the initial compaction stage. In the elastic stage,the coal seam may experience the best compaction degree and the fastest wave velocity change;and, (2) The holes and fissures produced by the coal stress may experience a significant impact on the sound waves.Besides,in the elastic stage,the coal body may experience a higher degree compaction,with a minor evolving degree of holes and fissures,so as for the wave velocity variation to reach its maximum. And,then,in the novel stage,the coal body would also experience a higher degree development of its holes and fissures,with the significant decline in the wave velocity variation;(3) Through the analysis of the wave velocity rate change,it would be possible for us to gain the changing degree of the coal body. And,it is just due to the fact that,the higher the wave velocity changing rate,the less obvious the changing degree of the coal body,and,consequently,the lower the development degree of the pores and fractures of the coal body,and so can be vice versa.
作者
李东会
梁雁侠
陈卓
张凯
LI Dong-hui;LIANG Yan-xia;CHEN Zhuo;ZHANG Kai(State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Henan Polytechnic University,Jiaozuo 454000,Henan,China;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Jiaozuo 454000,Henan,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2020年第3期906-912,共7页
Journal of Safety and Environment
基金
河南省自然科学基金项目(182300410138)
河南省博士后经费项目(19030070)
河南联合国家自然科学基金项目(U1704129)。
关键词
安全工程
超声波
三轴压缩
力学
裂隙
波速变化量
safety engineering
ultrasonic
triaxial compression
mechanics
crack
change in wave velocity
