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孟村煤矿坚硬顶板工作面冲击地压防治技术应用

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陕西煤炭 2022年第2期41卷 123-129页

作者：凌志强张天军庞明坤马小辉西安科技大学安全科学与工程学院陕西西安710054 国家矿山安全监察局陕西局陕西西安710018 陕西彬长孟村矿业有限公司陕西咸阳713500

为获取强冲击危险工作面的防冲关键数据,针对孟村煤矿401101首采工作面具有的坚硬顶板、大断层、大向斜等地质构造特点,在回采期间对工作面回风巷开展水力压裂弱化坚硬顶板技术试验,同时布设微震监测系统对试验期间的冲击地压能量事件... 详细信息

为获取强冲击危险工作面的防冲关键数据,针对孟村煤矿401101首采工作面具有的坚硬顶板、大断层、大向斜等地质构造特点,在回采期间对工作面回风巷开展水力压裂弱化坚硬顶板技术试验,同时布设微震监测系统对试验期间的冲击地压能量事件进行监测,以考察压裂的实际效果。试验结果表明,工作面推采至压裂区域后,日均总能量及频次都降低了17%;回顺范围内的每日微震事件总能量和频次普遍比运顺低,尤其在受F1断层影响的区域更为明显;进入压裂区后,回顺侧大能量事件随即有所降低,运顺侧较为滞后,且发生在工作面前方的微震事件占比逐渐增大,微震事件逐渐由工作面后方向工作面前方转移,同时,微震事件位置在工作面前方范围内基本呈均匀分布。

关键词：孟村煤矿坚硬顶板强冲击危险工作面水力压裂冲击地压防治

基于雷诺数的级配结构破碎煤样渗流失稳特征研究

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采矿与安全工程学报 2019年第6期36卷 1273-1280页

作者：张天军彭文清庞明坤张卫东孙海涛吴教锟西安科技大学理学院陕西省崔家沟煤矿中国煤炭科工集团重庆研究院有限公司瓦斯分院

为获得不同级配结构下破碎煤岩体渗流失稳特征,本文采用自主研发的破碎样渗流试验系统,研究了位移与渗透压改变时不同级配结构下破碎煤样的渗流参量及雷诺数变化规律,通过两者变化规律分析得出渗流失稳临界特征值。结果表明:1)试验过程... 详细信息

为获得不同级配结构下破碎煤岩体渗流失稳特征,本文采用自主研发的破碎样渗流试验系统,研究了位移与渗透压改变时不同级配结构下破碎煤样的渗流参量及雷诺数变化规律,通过两者变化规律分析得出渗流失稳临界特征值。结果表明:1)试验过程中4组破碎煤样的渗流速度与压力梯度关系均呈现非线性特征,骨架密实结构破碎煤样渗透率最大,非达西因子最小,悬浮密实结构破碎煤样渗透率最小,非达西因子最大,骨架空隙结构破碎煤样渗透参量受孔隙率影响变化较大;2)各组破碎煤样的雷诺数最小为0.1,最大为12.66,其中以悬浮密实结构破碎煤样雷诺数最大,骨架密实结构破碎煤样雷诺数最小,骨架空隙结构破碎煤样雷诺数变化小。研究可见,破碎煤样发生渗流失稳时存在临界特征值,悬浮密实结构以及骨架孔隙结构破碎煤样渗流失稳临界雷诺数为3,骨架密实结构破碎煤样临界雷诺数为5。

关键词：破碎煤岩级配结构非线性渗流渗流失稳雷诺数

Non-isothermal creep age forming of Al-Cu-Li alloy:Experiment and modelling

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Chinese Journal of Aeronautics 2023年第5期36卷 566-581页

作者： Changhui WU Heng LI tianjun BIAN Chao LEI Liwen zhang State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China

Non-isothermal Creep Age Forming(CAF),including loading,heating,holding,cooling and springback stages,is an advanced forming technique for manufacturing high performance large integral panels at short production period and low ***,the creep deformation and aging precipitation during heating stage is often neglected in experiments and modeling,leading to low forming *** achieve shape forming and property tailoring simultaneously,a deep understanding of the non-isothermal creep aging behavior and the establishment of predictive models are urgently required.A new five-stage creep feature of Al-Cu-Li alloy during the non-isothermal creep aging is *** microstructural interactions between the dislocations,solute atoms,Guinier Preston zones(GP zones)and T1 precipitates are found to dominate the five-stage creep aging *** physical-based model considering temperature evolution history is established to describe the five-stage creep *** springback and yield strength of non-isothermal creep age formed plates with different thicknesses are predicted and compared by non-isothermal CAF experiments and corresponding *** CAF experiments show that the springback and yield strength of the non-isothermal creep age formed plate are 62.1%and 506 MPa,*** results are in good agreement with experimental *** proposed model broadens the application of traditional CAF models that mainly focus on isothermal conditions.

关键词： Al-Cu-Li alloy Creep aging forming Microstructures Springback Mechanical properties Thickness

不同浸水时间级配破碎煤样的粒度分布分形特征

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采矿与安全工程学报 2018年第3期35卷 598-604页

作者：张天军陈佳伟包若羽蒋兴科周敖葛迪西安科技大学理学院陕西西安710054 西安科技大学安全科学与工程学院陕西西安710054

含水条件下破碎岩体的变形及压实是引发采空区地表沉降的因素之一。为探究浸水时间、级配、轴向压缩位移3种因素对承载破碎岩体粒度分布分形特征及压实特性的影响规律,采用轴向压缩位移控制的方法,进行了小位移情况下5组不同配比破碎煤... 详细信息

含水条件下破碎岩体的变形及压实是引发采空区地表沉降的因素之一。为探究浸水时间、级配、轴向压缩位移3种因素对承载破碎岩体粒度分布分形特征及压实特性的影响规律,采用轴向压缩位移控制的方法,进行了小位移情况下5组不同配比破碎煤样的侧限压实试验。结果表明:1)在轴向压缩位移较小的情况下,随着浸水时间的增加,同级配破碎煤样粒度分布分形维数呈减小趋势;2)浸水时间与粒径分布分形维数曲线可用指数函数拟合;3)随着配比指数n的增大,粒度分布分形维数逐渐减小;4)随着轴向压缩位移的增加,同级配破碎煤样粒度分布分形维数与轴向应力都呈增加趋势,可以分为0~15 mm的缓慢增加阶段和15 mm后的快速增加阶段。基于破碎煤样在不同浸水时间条件下承载能力与粒度分布特征的变化规律,得出其承载能力随浸水时间增加而降低,而粒度分布分形维数呈减小趋势,从而为进一步研究破碎岩体承载条件下的强度、变形及粒度分布特征提供依据。

关键词：小位移浸水时间粒度分布分形维数级配破碎煤样

Change in Precipitation over the Tibetan Plateau Projected by Weighted CMIP6 Models

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Advances in Atmospheric Sciences 2022年第7期39卷 1133-1150页

作者： Yin ZHAO tianjun ZHOU Wenxia zhang Jian LI LASG Institute of Atmospheric PhysicsChinese Academy of ScienceBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100049China

Precipitation over the Tibetan Plateau(TP)is important to local and downstream *** on a weighting method considering model skill and independence,changes in the TP precipitation for near-term(2021-40),mid-term(2041-60)and long-term(2081-2100)under shared socio-economic pathways(SSP1-1.9,SSP1-2.6,SSP2-4.5,SSSP3-7.0,SSP5-8.5)are projected with 27 models from the latest Sixth Phase of the Couple Model Intercomparison *** annual mean precipitation is projected to increase by 7.4%-21.6%under five SSPs with a stronger change in the northern TP by the end of the 21st century relative to the present *** in the TP precipitation at seasonal scales show a similar moistening trend to that of annual mean precipitation,except for the drying trend in winter precipitation along the southern edges of the *** generally suggests a slightly stronger increase in TP precipitation with reduced model uncertainty compared to equally-weighted *** effect of weighting exhibits spatial and seasonal ***,weighting leads to a prevailing enhancement of increase in spring precipitation over the ***,the influence of weighting is more remarkable over the northwestern TP regarding the annual,summer and autumn *** between weighted and original MMEs can give us more confidence in a stronger increase in precipitation over the TP,especially for the season of spring and the region of the northwestern TP,which requires additional attention in decision making.

关键词： model weighting precipitation the Tibetan Plateau CMIP6 projection