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深部煤巷两帮造穴卸压围岩主应力差演化规律及应用

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中南大学学报:英文版 2023年第7期30卷 2266-2283页

作者：陈冬冬蒋再胜马翔谢生荣王恩李辉 School of Energy and mining Engineering China University of Mining and Technology-BeijingBeijing 100083China Beijing Key Laboratory for Precise mining of Intergrown Energy and Resources(China University of Mining and Technology-Beijing) Beijing 100083China

常规钻孔卸压、松动爆破卸压技术对煤巷浅部锚固围岩带来一定程度的损伤,不能解决卸压与锚固之间的冲突。本文采用强锚和卸压协同控制技术来平衡上述冲突。采用数值模拟方法研究不同卸压参量对煤巷围岩主应力差的响应演化规律,确定合理... 详细信息

常规钻孔卸压、松动爆破卸压技术对煤巷浅部锚固围岩带来一定程度的损伤,不能解决卸压与锚固之间的冲突。本文采用强锚和卸压协同控制技术来平衡上述冲突。采用数值模拟方法研究不同卸压参量对煤巷围岩主应力差的响应演化规律,确定合理的卸压关键参数并讨论各参量影响程度。研究结果表明:1)当造穴深度较小时,主应力差峰值带不能有效转移至深部围岩;当造穴深度较大时,巷帮主应力差峰值带呈双高峰分布,造成无效卸压;当造穴深度为10 m时,巷帮新主应力差峰值带向深部围岩转移7.5 m且并未损害巷帮浅部锚固区域功能。2)增加造穴长度不会导致造穴孔洞起端至巷道壁之间主应力差形状及量值改变,仅能造成第二主应力差峰值位置及量值改变,且第二主应力差峰值位置的迁移程度远大于其量值的增长幅度。3)当造穴排距大于5 m时,相邻造穴孔洞间将出现主应力差高峰区域,导致相邻孔洞间卸压不充分;当造穴排距小于5 m时,各造穴孔洞产生的主应力差低值区域将互相连通,在巷帮深部形成一条连贯的主应力差卸压带。基于上述煤巷两帮造穴卸压围岩主应力差演化的规律获得了造穴最佳参数并将其应用于工程实践,现场应用结果表明强锚和卸压协同控制技术可有效解决深部煤巷围岩持续大变形控制的难题。

关键词：深部矿井软碎煤巷大孔造穴主应力差卸压技术

Tribo-corrosion interaction of the parallel steel wires in the suspension bridges

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摩擦:英文版 2023年第12期11卷 2221-2237页

作者： Bo WANG Dagang WANG Hailang CHONG Guozheng XIE Dekun ZHANG Shirong GE School of Mechatronic Engineering China University of Mining and TechnologyXuzhou 221116China School of Materials and Physics China University of Mining and TechnologyXuzhou 221116China College of Mechatronic Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The effect of contact load and relative displacement on tribo-corrosion interaction of parallel steel wires of main cable in the suspension bridge was investigated in this study.A self-made tribo-corrosion test bench was employed to conduct tribo-corrosion tests of parallel steel wires in 3.5%(wt%)NaCl solution and deionized water under different contact loads and different relative displacements.The friction coefficient and wear coefficient of wires were presented.Electrochemical corrosion behavior(Tafel polarization curves,Nyquist diagram,and equivalent circuit diagram)was characterized by electrochemical analyzer.Wear morphology was observed by scanning electron microscope.Wear volume loss and corrosion‒wear interaction were quantitatively demonstrated by high-precision weighing balance.The results show that the electrochemical corrosion ability of the steel wires increases with the increase of the contact load or relative displacement.The increased contact load or relative displacement increases the volume loss of corrosion‒wear and pure wear,but decreases the wear coefficient.The wear mechanisms in 3.5%NaCl solution are adhesive wear,abrasive wear,and corrosive wear as compared to adhesive wear and abrasive wear in deionized water under different contact loads.The wear mechanisms of parallel steel wires are slightly different under different relative displacements.But the main wear mechanisms are similar to that under different contact loads.The interaction effects of corrosion and wear produced by the contact load and relative displacement are all the synergistic effects.

关键词： main cable parallel steel wires friction corrosion‒wear interaction

Wear mechanism and debris analysis of PEEK as an alternative to CoCrMo in the femoral component of total knee replacement

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Friction 2023年第10期11卷 1845-1861页

作者： Xinyue ZHANG Tao ZHANG Kai CHEN Handong XU Cunao FENG Dekun ZHANG School of Mechatronic Engineering China University of Mining and TechnologyXuzhou 221116China School of Materials and Physics China University of Mining and TechnologyXuzhou 221116China

The polyetheretherketone(PEEK)-highly cross-linked polyethylene(XLPE),all-polymer knee prosthesis has excellent prospects for replacing the traditional metal/ceramic-polyethylene joint prosthesis,improving the service life of the joint prosthesis and the quality of patients’life.The long-term wear mechanism of PEEK-XLPE knee joint prosthesis is comprehensively evaluated from wear amount,wear morphology,and wear debris compared to that of CoCrMo-XLPE joint prosthesis.After 5 million cycles of in vitro wear,the wear loss of XLPE in PEEK-XLPE(30.9±3.2 mg)is lower than that of XLPE in CoCrMo-XLPE(32.1±3.1 mg).Compared to the XLPE in CoCrMo-XLPE,the plastic deformation of XLPE in PEEK-XLPE is more severe in the early stage,and the adhesive peeling and adhesion are lighter in the later stage.The size distribution of XLPE wear debris in PEEK-XLPE is relatively dispersed,which in CoCrMo-XLPE is relatively concentrated.Wear debris is mainly flake and block debris,and the wear mechanism of XLPE was abrasive wear.The wear volume per unit area of PEEK femoral condyle(10.45×10^(5)μm^(3)/mm^(2))is higher than that of CoCrMo(8.32×10^(5)μm^(3)/mm^(2)).The PEEK surface is mainly furrows and adhesions,while the CoCrMo surface is mainly furrows and corrosion spots.The PEEK wear debris is mainly in flakes and blocks,and the CoCrMo wear debris is mainly in the shape of rods and blocks.The wear mechanism of PEEK is abrasive wear and adhesion,and that of CoCrMo is abrasive wear and corrosion.

关键词： polyetheretherketone(PEEK)-highly cross-linked polyethylene(XLPE) cobalt-chromium-molybdenum(CoCrMo)-XLPE wear debris wear mechanism

倾斜煤层长壁开采承压底板力学结构及渗流稳定性分析

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Journal of Central South university 2023年第9期30卷 2948-2965页

作者：梁帅帅张东升范钢伟 KOVALSKY Evgeny 范张磊张磊韩学森 School of Mines China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Coal Resources and Safe mining China University of Mining and TechnologyXuzhou 221116China Department of mining Engineering Saint Petersburg Mining UniversitySaint Petersburg 199106Russia

倾斜煤层开采底板破坏易造成水资源流失甚至突水灾害问题,倾斜煤层产量在中国总产量中占有一定比例,因此,开展关于地面结构对地下开采响应稳定性的研究有重要意义。首先,通过分析底板应力状态与变形破坏规律,建立了双向线性载荷作用下... 详细信息

倾斜煤层开采底板破坏易造成水资源流失甚至突水灾害问题,倾斜煤层产量在中国总产量中占有一定比例,因此,开展关于地面结构对地下开采响应稳定性的研究有重要意义。首先,通过分析底板应力状态与变形破坏规律,建立了双向线性载荷作用下四边固支倾斜层合板模型;然后,通过研究渗透系数与变形之间的关系得到渗流稳定性判别方法及条件,并通过工程案例确定了倾斜煤层保水开采的影响因素及其敏感性。倾斜煤层底板最大挠度工作面方向位于工作面中下部0.5864倍的工作面长度处,推进方向上位于0.5864倍的工作面推进距离处。通过正交试验分析得出底板挠度影响因素的显著性大小排序为:工作面长度>水压>推进度>地层倾角。层合板中上层层位边界为压应力区域,中部为拉应力区域,中下层层位则相反,剪应力分区域集中分布。工作面下侧区域各应力最大值均大于上侧区域的,表现出明显的非对称性。最后,确定了渗流稳定性评价指标及稳定条件:极限渗透系数(K_(li))与等效渗透系数(K_(eq))之比不小于1,即K_(li)/K_(eq)≥1。渗流稳定性影响因素的显著性大小为:水压>工作面长度>地层倾角,可为类似矿井的保水开采提供建议。

关键词：层合板模型倾斜煤层结构稳定性渗流稳定性等效渗透系数正交分析显著性分析

Experimental study on the interrelation of multiple mechanical parameters in overburden rock caving process during coal mining in longwall panel

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International Journal of Coal Science & technology 2023年第4期10卷 265-289页

作者： Daixin Deng Hongwei Wang Lili Xie Zeliang Wang Jiaqi Song School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China State Key Laboratory of Coal Resources and Safe mining China University of Mining and TechnologyBeijing 100083China

In order to comprehend the dynamic disaster mechanism induced by overburden rock caving during the advancement of a coal mining face, a physical simulation model is constructed basing on the geological condition of the 21221 mining face at Qianqiu coal mine in Henan Province, china. This study established, a comprehensive monitoring system to investigate the interrelations and evolutionary characteristics among multiple mechanical parameters, including mining-induced stress, displacement, temperature, and acoustic emission events during overburden rock caving. It is suggested that, despite the uniformity of the overburden rock caving interval, the main characteristic of overburden rock lies in its uneven caving strength. The mining-induced stress exhibits a reasonable interrelation with the displacement, temperature, and acoustic emission events of the rock strata. With the advancement of the coal seam, the mining-induced stress undergoes four successive stages: gentle stability, gradual accumulation, high-level mutation, and a return to stability. The variations in other mechanical parameters does not synchronize with the signifcant changes in mining-induced stress. Before the collapse of overburden rock occurs, rock strata temperature increment decreases and the acoustic emission ringing counts surges with the increase of rock strata displacement and mining-induced stress. Therefore, the collaborative characteristics of mining-induced stress, displacement, temperature, and acoustic emission ringing counts can be identifed as the precursor information or overburden rock caving. These results are in good consistent with on-site situation in the coal mine.

关键词： Overburden rock caving Multiple mechanical parameters Interrelation characterization Precursor information

Investigations of the effects of two typical jet crushing methods on the atomization and dust reduction performance of nozzles

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International Journal of Coal Science & technology 2023年第4期10卷 92-106页

作者： Han Han Hetang Wang Qi Zhang Yunhe Du Haojie Wang Hui Wang State Key Laboratory of Coal Resources and Safe mining China University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

Single-fuid nozzles and dual-fuid nozzles are the two typical jet crushing methods used in spray dust reduction. To distinguish the atomization mechanism of single-fuid and dual-fuid nozzles and improve dust control efciency at the coal mining faces, the atomization characteristics and dust reduction performance of the two nozzles were quantitatively compared. Results of experiments show that, as water supply pressure increased, the atomization angle of the swirl pressure nozzle reaches a maximum of 62° at 6 MPa and then decreases, but its droplet size shows an opposite trend with a minimum of 41.7 μm. The water supply pressure helps to improve the droplet size and the atomization angle of the internal mixing air–liquid nozzle, while the air supply pressure has a suppressive efect for them. When the water supply pressure is 0.2 MPa and the air supply pressure reaches 0.4 MPa, the nozzle obtains the smallest droplet size which is 10% smaller than the swirl pressure nozzle. Combined with the dust reduction experimental results, when the water consumption at the working surface is not limited, using the swirl pressure nozzle will achieve a better dust reduction efect. However, the internal mixing air–liquid nozzle can achieve better and more economical dust reduction performance in working environments where water consumption is limited.

关键词： Dust control Spray nozzle Atomization characteristics Dust reduction performance

Experimental study of coal flow characteristics under mining disturbance in china

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International Journal of Coal Science & technology 2022年第5期9卷 32-47页

作者： Lei Zhang Zihao Kan Cun Zhang Jun Tang State Key Laboratory of Coal Resources and Safe mining School of MinesChina University of Mining and TechnologyXuzhou 221116JiangsuChina School of Energy and mining Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

With annually increased coal mining depth,gas extraction becomes more and more problematic.The gas extraction efect depends on coal seam permeability,which,in turn,is afected by many factors,including loading and unloading stresses and strains in the coal seam.Stresses induce internal cracks,resulting in cleats and gas emission channels,the coal seam permeability permanently changes accordingly.To clarify the stress-induced efects on coal seam permeability,this survey summarized the available approaches used to link the stress path and seepage law in the coal body seepage law,which can be classifed into two design methods:single load variation and combined feld mining method.The characterization methods used to observe the surface of coal samples and three-dimensional reconstruction include electron microscopy,CT scanning,and Nuclear Magnetic Resonance(NMR).According to the stress paths designed by the above two approaches,the seepage laws and similarities of three kinds of coal samples with the fractured structure were summarized in this paper.The following directions are recommended to study the seepage law of coal bodies with three kinds of fractured structures under stress.Firstly,the stress path of the experimental coal body should be designed by the combined feld mining method.The stressed environment of a deep coal seam is complicated,and the axial and confning pressures change simultaneously.Therefore,one cannot fully refect the real situation on-site by studying permeability evolution alone.Secondly,during the coal seam mining,the stressed state changes from time to time,and the development of coal seam fractures is afected by mining.When studying the stress efect on seepage of coal samples,the fractured structure of coal samples should be considered.Finally,the available structural characterization methods of coal samples can be combined with the 3D printing technology,which would produce artifcial samples with the fractured structure characteristics of natural coal.

关键词： Stress loading and unloading Structural characterization Permeability Fracture structure Broken coal

密集钻孔弱化坚硬顶板机理的数值模拟及应用研究

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Journal of Central South university 2023年第6期30卷 1865-1886页

作者：马军强李学华姚强岭夏泽徐强山长昊 Andrey SIDORENKO Aleksei APARIN Key Laboratory of Deep Coal Resource mining(Ministry of Education) China University of Mining and TechnologyXuzhou 221116China Faculty of mining Engineering Saint Petersburg Mining UniversitySaint Petersburg 199106Russia School of Mines China University of Mining and TechnologyXuzhou 221116China

煤矿坚硬顶板工作面回采后形成的侧向悬臂梁结构导致邻近工作面回采巷道和煤柱处于高应力状态,使得邻近工作面回采巷道围岩矿压显现剧烈。本文提出了一种密集钻孔诱导形成非连续弱面弱化坚硬顶板的技术方法。根据察哈素煤矿31315工作面... 详细信息

煤矿坚硬顶板工作面回采后形成的侧向悬臂梁结构导致邻近工作面回采巷道和煤柱处于高应力状态,使得邻近工作面回采巷道围岩矿压显现剧烈。本文提出了一种密集钻孔诱导形成非连续弱面弱化坚硬顶板的技术方法。根据察哈素煤矿31315工作面的工程地质条件,采用颗粒流数值计算软件PFC^(2D)建立了数值计算模型,研究了密集钻孔周围的应力响应机制和裂缝扩展规律。研究发现,密集钻孔开挖后,钻孔周围岩体因受集中应力而出现渐进性破坏并形成以最小水平主应力方向为长轴,最大水平主应力方向为短轴的椭圆形卸压区。同时,当钻孔直径(D)由30 mm增加到133 mm时,卸压区面积比(λ)从0增加到6.42%,卸压区宽度比(μ)从11.55%增加到54.6%。当钻孔间距(L)从300 mm增加到700 mm时,λ从30.86%减小到9.74%,μ从63.9%减小到33.2%,表明采用较大的直径和较小的间距能够提高密集钻孔对坚硬顶板岩层的弱化程度及卸压效果。现场工业性试验结果表明,密集钻孔诱导形成的非连续弱面有效地弱化了顶板岩层的强度,促进了工作面回采后侧向悬臂结构及时垮落,优化了巷道围岩所处的应力环境,保证了工作面生产安全。本研究为煤矿坚硬顶板的控制方案提供了一种新的技术方法。

关键词：密集钻孔非连续弱面切顶卸压回采巷道稳定性颗粒流数值计算软件(PFC^(2D))

Schemes for Generating Different Nonlinear Schrodinger Integrable Equations and Their Some Properties

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Acta Mathematicae Applicatae Sinica 2022年第3期38卷 579-600页

作者： Yu-feng ZHANG Hai-feng WANG Na BAI School of Mathematics China University of Mining and TechnologyXuzhou 221116China School of Computer Science and technology China University of Mining and TechnologyXuzhou 221116China

In the paper,we want to derive a few of nonlinear Schrodinger equations with various formats and investigate their properties,such as symmetries,single soliton solutions,multi-soliton solutions,and so on.First of all,we propose an efficient and straightforward scheme for generating nonisospectral integrable hierarchies of evolution equations for which a generalized nonisospectral integrable Schrodinger hierarchy(briefly GNISH)singles out,from which we get a derivative nonlinear Schrodinger equation,a generalized nonlocal Schrodinger integrable system and furthermore we investigate the symmetries and conserved qualities of the GNISH.Next,we apply the dbar method to obtain a generalized nonlinear Schr?dinger-Maxwell-Bloch(GNLS-MB)equation and its hierarchy by introducing a generalized Zakhrov-Shabat spectral problem,whose soliton solutions and gauge transformations are obtained.

关键词： nonisospectral integrable hierarchy Schroodinger equation symmetry