Length-to-diameter ratio effect of dynamic deformation modulus of coal under three-dimensional dynamic and static loading

被引：0

作者：

Sun Z. ^{[1
,2
,3
,4
]}

Wu Y. ^{[1
,2
,3
,4
]}

Sun J. ^{[5
]}

Chen J. ^{[1
,2
,3
,4
]}

Fu Y. ^{[1
,2
,3
,4
]}

Shan S. ^{[1
,2
,3
,4
]}

机构：

[1] CCTEG Coal Mining Research Institute, Beijing

[2] Coal Mining and Designing Department, Tiandi Science and Technology Co.，Ltd., Beijing

[3] Coal Mining Branch, China Coal Research Institute, Beijing

[4] State Key Laboratory of Coal Mining and Clean Utilization, China Coal Research Institute, Beijing

[5] Heilongjiang Longmei Shuangyashan Mining Co.，Ltd., Shuangyashan

来源：

Journal of Mining and Strata Control Engineering | 2022年 / 4卷 / 04期

关键词：

rock dynamics; rockburst; secant modulus; SHPB; strain rate;

D O I：

10.13532/j.jmsce.cn10-1638/td.20220224.001

中图分类号：

学科分类号：

摘要：

With the frequent occurrence of rockburst in coal mines，the measurement of dynamic mechanical properties of coal and rock under impact load has become an important means to study the mechanism of rockburst. Dynamic deformation modulus is an important parameter to characterize the deformation resistance of coal and rock under impact load. In order to study the length-to-diameter ratio effect of dynamic deformation modulus of coal under three-dimensional dynamic and static loading，samples were taken from rockburst mine. Four groups of cylinder coal samples with diameter of 50 mm and length-to-diameter ratio of 0.5，0.6，0.8 and 1.0 were taken as the research objects. Based on the in-situ test results，the preloaded static loads of axial pressure and confining pressure were designed，and the three-dimensional dynamic and static loading test was carried out by using the improved Hopkinson compression bar (SHPB) test system. The results show that，according to the characteristics of dynamic stress-strain curve，the secant modulus of elastic and plastic section is defined. It is found that there is a significant strain rate effect on the secant modulus of plastic section，and the strain rate sensitivity of secant modulus of plastic section with large length-to-diameter ratio is stronger than that with small length-to-diameter ratio. Under the same strain rate，the secant modulus of plastic section increases with the increase of length-to-diameter ratio，and the greater the strain rate，the more significant the length-to-diameter ratio effect of secant modulus of plastic section. The intermittent climbing behavior in the front section of the peak curve under three-dimensional dynamic and static loading makes the 50% dynamic peak stress points of each sample appear disorderly distribution，which is the main reason for the irregularity of the existing dynamic deformation modulus and strain rate. The research results are helpful to explore the deformation characteristics of roadway surrounding rock under the superposition of dynamic and static loads，and provide theoretical support for controlling roadway surrounding rock in rockburst coal mines. © 2022 Science Press. All rights reserved.

引用

共 28 条

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