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A consecutive joint shear strength model considering the 3D roughness of real contact joint surface

International Journal of Mining Science and Technology 2023年第5期33卷 617-624页

作者： Liren Ban Zhigang Tao weisheng du Yuhang Hou School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China State Key Laboratory of Deep Geotechnical Mechanics and Deep Underground Engineering Beijing 100083China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China Deep Mining and Rock Burst Research Branch China Coal Research InstituteBeijing 100013China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China

A consecutive joint shear strength model for soft rock joints is proposed in this paper,which takes into account the degradation law of the actual contact three-dimensional(3D)*** essence of the degradation of the maximum possible dilation angle is the degradation of the 3D average equivalent dip angle of the actual contact joint ***,models for calculating the maximum possible dilation angle at the initial and residual shear stress stages are proposed by analyzing the 3D joint morphology characteristics of the corresponding shear ***,the variation law of the maximum possible dilation angle is quantified by studying the degradation law of the joint micro convex *** on the variation law of the maximum possible dilation angle,the maximum possible shear strength model is ***,a method to calculate the shear stiffness degradation in the plastic stage is *** to the maximum possible shear strength of rock joints,the shear stress-shear displacement prediction model of rock joints is *** new model reveals that there is a close relationship between joint shear strength and actual contact joint roughness,and the degradation of shear strength after the peak is due to the degradation of actual contact joint roughness.

关键词： Shear strength Actual contact area 3D roughness Shear test

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A roughness parameter considering joint material properties and peak shear strength model for rock joints

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International Journal of Mining Science and Technology 2021年第3期31卷 413-420页

作者： Liren Ban weisheng du Tianwei Jin Chengzhi Qi Xiaozhao Li School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Deep Mining and Rock Burst Research Institute China Coal Research InstituteBeijing 100013China State Key Laboratory of Coal Mining and Clean Utilization China Coal Research InstituteBeijing 100013China

This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength(PSS)of rock ***,the contribution of the asperities with different apparent dip angles to shear strength is *** the shear strength of the entire joint asperities is *** results showed that the PSS of the entire joint asperities is proportional to a key parameter hs,which is related to the geometric character of the joint surface and the joint material *** parameter hsis taken as the new roughness parameter,and it is reasonable to associate the PSS with the geometric characteristics of the joint *** on the new roughness parameter and shear test results of 20 sets of joint specimens,a new PSS model for rock joints is *** new model is validated with the artificial joints in this paper and real rock joints in published *** showed that it is suitable for different types of rock joints except for gneiss *** new model has the form of the Mohr-Coulomb model,which can directly reflect the relationship between the 3 D roughness parameters and the peak dilation angle.

关键词： Roughness Joint material properties Rock joints Peak shear strength Asperities

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Dynamic tensile behaviour and crack propagation of coal under coupled static-dynamic loading

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International Journal of Mining Science and Technology 2020年第5期30卷 659-668页

作者： Xianjie Hao weisheng du Yixin Zhao Zhuowen Sun Qian Zhang Shaohua Wang Haiqing Qiao Beijing Key Laboratory for Precise Mining of Inter-grown Energy and Resources China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Water Resource Protection and Utilization in Coal Mining Beijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China School of Energy and Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China

The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of *** this study,coupled static-dynamic loading tests are conducted on Brazilian disc(BD)coal specimens using a modified split Hopkinson pressure bar(SHPB).The effects of the static axial pre-stress and loading rate on the dynamic tensile strength and crack propagation characteristics of BD coal specimens are *** average dynamic indirect tensile strength of coal specimens increases first and then decreases with the static axial pre-stress *** no static axial pre-stress is applied,or the static axial pre-stress is 30%of the static tensile strength,the dynamic indirect tensile strength of coal specimens shows an increase trend as the loading rate *** the static axial pre-stress is 60%of the static tensile strength,the dynamic indirect tensile strength shows a fluctuant trend as the loading rate *** to the crack propagation process of coal specimens recorded by high-speed camera,the impact velocity influences the mode of crack propagation,while the static axial pre-stress influences the direction of crack *** failure of coal specimens is a coupled tensile-shear failure under high impact *** there is no static axial pre-stress,tensile cracks occur in the vertical loading *** the static axial pre-stress is applied,the number of cracks perpendicular to the loading direction decreases,and more cracks occur in the parallel loading direction.

关键词： Coal Coupled static-dynamic loading SHPB Dynamic fracture behaviour Crack propagation

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A Pair of New Spirocyclic Alkaloid Enantiomers with TrxR Inhibitory Activities Were Isolated from Marine-Derived Aspergillus ruber TX-M4-1

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Journal of Ocean University of China 2023年第6期22卷 1677-1682页

作者： WANG Cong WANG Yufei SUN Jian WANG Shiyi du weisheng ZHOU Liman KONG Fandong Key Laboratory of Chemistry and Engineering of Forest Products State Ethnic Affairs CommissionGuangxi Key Laboratory of Chemistry and Engineering of Forest ProductsGuangxi Minzu UniversityNanning 530006China Guangxi Collaborative Innovation Center for Chemistry and Engineering of Forest Products Key Laboratory of Universities in Guangxi for Excavation and Development of Ancient Ethnomedicinal RecipesGuangxi Minzu UniversityNanning 530006China

One new spirocyclic alkaloid,5-isopentenyl-cryptoechinuline D(1),along with 11 known compounds(2–12),were iso-lated from a marine fungus Aspergillus ruber *** structures of compounds 1–12 were elucidated by spectroscopic *** 1 was initially isolated as an enantiomer,and further separation of 1 by chiral HPLC afforded a pair of enantio-mers,including(-)-5-isopentenyl-cryptoechinuline D(1a)and(+)-5-isopentenyl-cryptoechinuline D(1b).Their absolute configura-tions were elucidated by ECD spectroscopic *** 1a,5 and 10 could inhibit thioredoxin reductase(TrxR)activity with IC50 values of 6.2,36.3 and 18.6μmol L^(-1),*** plasmon resonance(SPR)study also demonsrated the interactions between compounds 6,8 and Niemann-Pick C1 Like 1(NPC1L1)respectively,which indicate that compounds 6 and 8 are potential NPC1L1 inhibitors.

关键词： Aspergillus ruber TX-M4-1 spirocyclic alkaloid TrxR inhibitory activity

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Investigation on the physical mechanism of cavity percentage dependent shear strength for rock joints considering the real contact joint surface

Rock Mechanics Bulletin

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Rock Mechanics Bulletin 2023年第4期2卷 1-11页

作者： Liren Ban Zefan Wang weisheng du Yuhang Hou Chengzhi Qi Jin Yu School of Civil and Transportation Engineering Beijing Advanced Innovation Center for Future Urban DesignBeijing University of Civil Engineering and ArchitectureBeijing 100044China Institute of Deep Earth Sciences China Institute of Coal ScienceBeijing 100013China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen 361021China

To explain the effect of joint roughness on joint peak shear strength(JPSS)and investigate the effect of different contact states of joint surface on JPSS,we try to clarify the physical mechanism of the effect of joint cavity percentage(JCP)on JPSS from the perspective of the three-dimensional(3D)distribution characteristics of the actual contact joint surface,and propose a JPSS model considering the *** tests for red sandstone joints with three different surface morphologies and three different JCPs were performed under constant normal load *** on test fitting results,the reduction effect of the JCP on JPSS is investigated,and a JPSS model for cavity-containing joints is ***,the above model only considers the influence of JCP by fitting test data,and does not reveal the physical mechanism of JCP affecting the *** on the peak dilation angle model for consideration of the actual contact joint morphology,and the influence of JCP on the roughness of the actual contact joint surface,a theoretical model of the JPSS considering the JCP is *** derivation process does not depend on the test fitting,but is entirely based on the joint mechanical law,and its physical significance is *** is proposed that the essence of the influence of the JCP on JPSS is that the JCP first affects the normal stress of the actual contact joints,further affects the roughness of actual contact joints,and then affects the shear strength.

关键词： Roughness Joint peak shear strength Joint shear test Surface morphology Cavity percentage

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拓片及其装帧与装裱

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图书馆工作与研究 2010年第9期 66-68+71页

作者：杜伟生国家图书馆

拓片是一种特殊的文献形式。本文就拓片的各种传拓方法、拓片的品种以及装帧形式作了比较详细的归纳和叙述,并对传统装裱形式的优缺点进行了分析。

关键词：古籍修复古籍装帧拓片装裱

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阐释《古籍修复技术规范与质量要求》

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国家图书馆学刊 2006年第3期15卷 19-25页

作者：杜伟生国家图书馆善本特藏部

《古籍修复技术规范与质量要求》是为了规范即将在全国图书馆开展的大规模古籍修复工作而制定的一个推荐性标准,内容涉及到古籍修复工作的各个方面。本文就标准的使用范围、结构、部分名词术语、质量工作标准以及在标准中反映的修复理... 详细信息

《古籍修复技术规范与质量要求》是为了规范即将在全国图书馆开展的大规模古籍修复工作而制定的一个推荐性标准,内容涉及到古籍修复工作的各个方面。本文就标准的使用范围、结构、部分名词术语、质量工作标准以及在标准中反映的修复理念、技术等方面作了简要的说明。

关键词：古籍保护古籍修复技术规范修复质量

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北京图书馆藏敦煌遗书赝本八种概述

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文献 1998年第3期 126-131页

作者：杜伟生北京图书馆善本部

本世纪初敦煌遗书的发现,引起各国考古界的注意。之后,大部分敦煌遗书流失到英、法、俄等国。其余部分在解送京师途中,又散失了一些。为搜集这些珍贵的唐代遗物,许多机构和个人想方设法、不惜重金购求。一些人在高额利润的诱惑下,制作... 详细信息

本世纪初敦煌遗书的发现,引起各国考古界的注意。之后,大部分敦煌遗书流失到英、法、俄等国。其余部分在解送京师途中,又散失了一些。为搜集这些珍贵的唐代遗物,许多机构和个人想方设法、不惜重金购求。一些人在高额利润的诱惑下,制作赝本欺世谋利。有些机构收藏的敦煌遗书中,不同程度掺杂着一些赝本。北京图书馆藏的敦煌遗书中,就有这种情况。在一万六千件敦煌遗书中,赝本的数量虽然不多。

关键词：敦煌遗书图书馆金刚经直接影响纸张纤维高额利润书法风格唐代制作韧皮纤维

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考虑实际接触三维粗糙度退化的软岩节理剪胀规律预测模型

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岩土工程学报 2024年第5期46卷 1008-1017页

作者：班力壬杜伟升候宇航戚承志陶志刚北京建筑大学土木与交通工程学院北京100044 煤炭科学研究总院有限公司深地科学院北京100013 中国矿业大学(北京)力学与建筑工程学院北京100083

为预测岩石节理的剪胀变形行为,分析了恒法向荷载作用下实际接触微凸体三维粗糙度在剪切过程中的退化规律,提出了一个适用于软岩节理的剪胀曲线预测模型。在剪切荷载作用下节理法向位移的变化是节理在三角形微凸体侧面爬坡上升行为与爬... 详细信息

为预测岩石节理的剪胀变形行为,分析了恒法向荷载作用下实际接触微凸体三维粗糙度在剪切过程中的退化规律,提出了一个适用于软岩节理的剪胀曲线预测模型。在剪切荷载作用下节理法向位移的变化是节理在三角形微凸体侧面爬坡上升行为与爬越一些微凸体顶点后闭合行为的叠加,爬坡行为与闭合行为引起的位移都正比于节理最大可能剪胀角。最大可能剪胀角退化的实质是实际接触节理微凸体平均等效倾角的退化。通过分析初始剪切与残余应力阶段的节理形貌特征,提出了计算初始最大可能剪胀角与残余应力阶段剪胀角的模型。基于软岩节理不发生突然脆性破坏的假设,进一步通过研究剪切过程中节理微凸体退化规律,量化了最大可能剪胀角的变化规律。定量了节理爬坡行为、闭合行为与最大可能剪胀角之间的关系,进而提出了节理剪胀规律预测模型,通过试验验证了模型的有效性。模型可较准确预测软岩节理的剪胀规律,并可合理描述节理初始阶段剪切压密行为。

关键词：节理剪胀形貌退化微凸体三维粗糙度节理形貌

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考虑实际接触节理微凸体对剪切强度不同贡献比例的峰值剪胀角模型

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煤炭学报 2023年第10期48卷 3688-3699页

作者：班力壬候宇航杜伟升俞缙戚承志单仁亮北京建筑大学土木与交通工程学院北京100044 煤炭科学研究总院有限公司深地科学院北京100013 华侨大学岩土工程研究所福建厦门361021 中国矿业大学(北京)力学与建筑工程学院北京100083

节理的剪切力学特性一直是岩石工程关注的重点,峰值剪胀角是描述节理抗剪能力的关键物理量,合理的峰值剪胀角模型应能充分反映节理的峰值抗剪强度。为预测节理峰值剪胀角,阐明节理峰值剪胀角与节理形貌的内在联系,首先明确了节理面上对... 详细信息

节理的剪切力学特性一直是岩石工程关注的重点,峰值剪胀角是描述节理抗剪能力的关键物理量,合理的峰值剪胀角模型应能充分反映节理的峰值抗剪强度。为预测节理峰值剪胀角,阐明节理峰值剪胀角与节理形貌的内在联系,首先明确了节理面上对剪切强度有贡献的微凸体分布范围,然后确定了实际接触节理中各部分微凸体对强度的贡献比例。在节理面上抵抗剪切的阻力是由面向剪切方向的所接触的微凸体产生的。提出了实际接触的最小视倾角θ_(cr1)^(*)和剪胀破坏过渡到剪断破坏的临界角度θ_(cr2)^(*)分别用于界定微凸体是否参与剪切过程,以及微凸体的破坏模式。对于有效视倾角θ^(*)在θ_(cr1)^(*)~θ_(cr2)^(*)间的微凸体,其破坏模式为剪胀破坏,对剪切强度的贡献正比于θ^(*)。对于θ^(*)在θ_(cr2)^(*)~θ_(max)^(*)(其中,θ_(max)^(*)为最大有效视倾角)间的微凸体,其破坏模式为剪断破坏,对剪切强度的贡献正比于θ_(cr2)^(*)。进一步考虑实际接触节理微凸体对剪切强度不同贡献比例与微凸体面积比含量,推导出了等效实际接触节理平均角。将等效实际接触节理平均角等同于节理峰值剪胀角,提出了新的节理峰值剪胀角模型。新模型物理意义明确,现有相关所提粗糙度指标仅仅是等效实际接触节理平均角的一种特殊情况。采用89组试验数据对比分析了6种模型的计算精度,结果表明新模型的预测精度最佳(平均误差为10%)。新的峰值剪胀角模型中确定θ_(cr2)^(*)较为关键,不同材料节理对应的临界角度θ_(cr2)^(*)不同,考虑到模型形式的简化,取θ_(cr2)^(*)=32°来统一确定新的峰值剪胀角模型。简化后的节理峰值剪胀角新模型估算的相对平均误差为11%,预测精度高于本文列举的多个模型。讨论了θ_(cr2)^(*)对不同形貌节理的影响及其取值依据。结果显示,节理粗糙度较大时,新模型精度高于其他模型,通过89组试验数据拟合得到θ_(cr2)^(*)取值是合理的。

关键词：剪切强度岩石节理节理微凸体岩石形貌实际接触

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