朱昌星，霍嘉鑫，吴大志.分形煤岩胶结体动态力学性能及数值模拟研究[J].河南理工大学学报(自然科学版)，doi:10.16186/j.cnki.1673-9787.2024030053

ZHU C X，HUO J X，WU D Z．Study on dynamic mechanical properties and numerical simulation of fractal coal-rock cement［J］.Journal of Henan Polytechnic University( Natural Science) ，doi:10.16186/j.cnki.1673-9787. 2024030053

分形煤岩胶结体动态力学性能及数值模拟研究(网络首发)

朱昌星，霍嘉鑫，吴大志

河南理工大学 土木工程学院，河南 焦作 454000

摘要: [目的] 为研究颗粒破碎程度对煤岩胶结体的动态力学性能影响，[方法] 基于松散介质固体颗粒分布规律理论，以分形维数分别为1.4，1.7，2.0，2.3，2.6配制不同破碎程度的松散煤体，按比例将胶凝材料与煤体拌合，经养护后制成标准块，对其进行分离式霍普金森压杆（SHPB）冲击试验，并利用有限元软件LS-DYNA对SHPB试验过程进行数值模拟和对比分析。[结果] 结果表明：分形维数1.7时抗压强度最低、分形维数2.6时抗压强度最高；煤岩破碎程度对试样的动态力学性能有较大影响；水泥基体的内能远大于4种粒径煤体内能之和；数值模拟的峰值应力、应变终值和破坏模式与室内试验结果吻合较好。粒径为0~20 mm时，0~5 mm的小颗粒质量占比越多，试样整体强度越高；胶结体动态抗压强度随着分形维数的增大呈先减小后增大的趋势；动态压缩下试块耗散能也呈先减后增的趋势；分形维数1.7的煤体级配不利于发挥胶结体试块的力学性能；水泥基体为主要的储能介质，承担主要的能量吸收与耗散；HJC参数的合理选取可以使数值模拟分析较好地反映胶结体试块的动态力学特性。[结论]研究结果可为后续煤岩注浆提供一定的技术支持。

关键词: 煤体破碎程度；胶结体；分离式霍普金森压杆；动态抗压强度；数值模拟

中图分类号：TD76

doi: 10.16186/j.cnki.1673-9787.2024030053

基金项目: 国家自然科学基金资助项目（51874119）；安全学科双一流创建课题培育项目基金资助项目（AQ20240726）；河南理工大学博士基金资助项目（B2009-96）

收稿日期：2024-03-19

修回日期：2024-06-21

网络首发日期：2024-08-20

Study on dynamic mechanical properties and numerical simulation of fractal coal-rock cement

ZHU changxing，HUO Jiaxin，WU Dazhi

School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454000,Henan, China

Abstract: [Objective]In order to study the influence of particle breakage degree on the dynamic mechanical properties of coal-rock cemented body, [Methods] Based on the theory of solid particle distribution in loose medium, loose coal with different crushing degree was prepared with fractal dimension of 1.4, 1.7, 2.0, 2.3 and 2.6 respectively, and the cementing material was mixed with the coal body in proportion to make standard block after curing. The split Hopkinson pressure bar(SHPB)impact test was carried out, and the finite element software LS-DYNA was used to simulate the SHPB test process. [Results] Experimental results: The compressive strength is the lowest when the fractal dimension is 1.7 and the highest when the fractal dimension is 2.6. The dynamic mechanical properties of coal and rock samples are greatly affected by the degree of coal fragmentation. The internal energy of cement matrix is much greater than the sum of the internal energy of coal with four particle sizes. The numerical simulation results of peak stress, strain and failure mode agree well with the experimental results. Results indicate: In the particle size range of 0~20 mm, the overall strength of the test block is higher when the proportion of small particles in the range of 0~5 mm is higher. The dynamic compressive strength of cement decreases first and then increases with the increase of fractal dimension. The dissipative energy of the test block also decreases first and then increases under dynamic compression. The media gradation with fractal dimension 1.7 is not conducive to the mechanical properties of the cement block. As the main energy storage medium, the cement matrix bears the main energy absorption and dissipation. The reasonable selection of HJC parameters can make the numerical simulation reflect the dynamic mechanical characteristics of the test block. [Conclusion] The research results can provide some technical support for the subsequent grouting of coal and rock.

Key words: coal crushing degree; cement body; Split Hopkinson Pressure Bar; dynamic compressive strength; numerical modeling

CLC: