不同加载速率下煤体裂隙演化特征分析

doi:10.16265/j.cnki.issn1003-3033.2022.11.2690

摘要/Abstract

摘要：

为研究加载速率对煤体裂隙演化的影响,开展不同加载速率下煤体单轴压缩试验;以原煤试件为研究对象,采用数字散斑技术和声发射技术,分析煤体力学参数、变形场演化云图和声发射信号参数三者之间的关系。结果表明:煤体的抗压强度和弹性模量随着加载速率的增加逐渐增大,抗压强度增加了25.49%,弹性模量增加了51.55%;煤体变形场演化云图和声发射事件空间分布可以表明裂隙发育、扩展及破裂的整个过程;随着加载速率的增大,煤体破坏类型由张拉破坏变为张拉剪切复合型破坏,煤体表面变形场局部化带的相对位移速率量值逐渐减小,声发射峰值计数、峰值能量和声发射事件数均出现增加趋势,累计计数、累积能量则降低;变形场演化云图和声发射事件的空间分布能较好反映煤体受载过程中裂隙的发育、扩展及破裂的演化特征。

关键词: 加载速率, 煤体, 裂隙演化, 演化特征, 单轴压缩试验, 声发射事件

Abstract:

In order to study the influence of loading rate on the evolution of coal fracture, uniaxial compression tests of coal under different loading rates were carried out. Taking raw coal samples as the research object, the relationship between coal mechanical parameters, deformation field evolution cloud map and acoustic emission signal parameters was analyzed by combining digital speckle technology and acoustic emission technology. The research shows that the compressive strength and elastic modulus of coal increase gradually with the increase of loading rate. The compressive strength increases by 25.49%, and the elastic modulus increases by 51.55%. The evolution nephogram of the coal deformation field and the spatial distribution of acoustic emission events can indicate the whole process of fracture development, expansion and fracture. With the increase of loading rate, the failure type of coal body changes from tensile failure to tensile shear composite failure. The relative displacement rate of the localization zone of the coal surface deformation field decreases gradually, and the peak count, peak energy and the number of acoustic emission events increase, while the cumulative count and cumulative energy decrease. The evolution nephogram of the deformation field and the spatial distribution of acoustic emission events can better reflect the evolution characteristics of fracture development, expansion and fracture during coal loading.

Key words: loading rate, coal, fracture evolution, evolution characteristics, uniaxial compression test, acoustic emission events

肖鹏, 高振, 双海清, 吴铭川, 程玥颖, 郭晨华. 不同加载速率下煤体裂隙演化特征分析[J]. 中国安全科学学报, 2022, 32(11): 65-73.

XIAO Peng, GAO Zhen, SHUANG Haiqing, WU Mingchuan, CHENG Yueying, GUO Chenhua. Analysis of coal fracture evolution characteristics under different loading rates[J]. China Safety Science Journal, 2022, 32(11): 65-73.

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加载速率/ (mm·min^-1)	相对位移速率最大量值/(mm·s^-1)
加载速率/ (mm·min^-1)	A1-A2	B1-B2	C1-C2
0.05	0.622	0.704	-
0.10	0.430	0.312	0.195
0.50	0.258	0.249	-
1.00	0.051	0.083	-

加载速率/ (mm·min^-1)	声发射峰值计数/个	声发射累计计数/个	声发射峰值能量/(mV·ms)	声发射累计能量/(mV·ms)	声发射事件累计数/个
0.05	225	267 344	1 005	29 765	2 090
0.10	293	102 902	1 504	24 577	1 224
0.50	414	65 064	2 229	10 185	890
1.00	1 262	25 861	3 347	8 825	786