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Homogenizing interfacial shear stress in brick-and-mortar structured composites via gradient modulus for enhanced mechanical properties

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Acta Mechanica Sinica 2024年第6期40卷 115-124页

作者： Yang Gao Jiawei He Jie Jiang jianping zuo School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China

Inspired by nature,various biomimetic materials have been synthesized for enhanced mechanical properties,among which composites with brick-and-mortar structures attract the most *** such bio-inspired composites,the matrix layer mainly functions to transfer load between bricks through shearing,while the shear stress in the matrix is not uniform but highly concentrated on the interface ends,which tends to initiate cracks and evoke interface delamination in *** enhance the composites’resistance to interface delamination,we propose to homogenize the shear stress by adopting a matrix with a gradient modulus.A theoretical solution to the optimal gradient modulus of the matrix layer is obtained,followed by computational ***,composites with such functionally graded matrices are further demonstrated to possess higher elastic limits,higher resilience,and flaw tolerance than the uniform *** results of this paper should be of great value to the design and synthesis of advanced structural materials for superior mechanical performance.

关键词： Stress concentration Interface delamination Brick-and-mortar structure Composite

深部底板水锤突水效应及递进–导升力学模型研究

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岩石力学与工程学报 2024年第8期43卷 1852-1869页

作者：左建平吴根水中国矿业大学(北京)力学与土木工程学院北京100083 中国矿业大学(北京)采矿岩石力学国际创新中心北京100083 湖南科技大学资源环境与安全工程学院湖南湘潭411201

矿井底板水害是影响深部煤矿安全生产的一种重要灾害。为深入研究深部底板复杂的突水现象,首先调查和分析华北地区工作面突水特征,认为大多突水事故是由于扰动应力和水压流固耦合作用综合导致底板的破断。在一定采动条件下,深部底板裂... 详细信息

矿井底板水害是影响深部煤矿安全生产的一种重要灾害。为深入研究深部底板复杂的突水现象,首先调查和分析华北地区工作面突水特征,认为大多突水事故是由于扰动应力和水压流固耦合作用综合导致底板的破断。在一定采动条件下,深部底板裂隙岩体通道内会形成由势能转变为动能(使运动的水获得加速度)的动水锤效应,对采场围岩有不同程度的损伤或者破坏,定义为水锤突水效应。深部岩体水锤效应形成本质是水体在裂隙通道的流动被瞬时截断,由此导致水体在通道里面反复循环冲击,裂隙通道围岩发生损伤,当该反复循环运动水体的能量积聚到一定状态,进而导致裂隙导升破裂,由此引发突水灾害。基于此思想,建立水锤影响下深部底板水的递进–导升力学模型,揭示裂隙岩体在水锤影响下可能促进突水通道形成。理论和数值研究结果综合表明,裂隙岩体通道中水流速度越快,通道瞬时截断形成水锤压强越大;受水锤效应影响,水楔作用将进一步地驱动岩体裂隙递进–导升破坏。最后,以华北型煤田为工程背景,对底板岩体水锤影响下突水类型进行分类:裂隙岩体水锤–水楔导升突水、隐伏断层应力潜蚀–断裂突水和大构造断层导通突水,并对受水锤影响下深部底板突水提出控制建议方法。水锤突水效应是笔者对煤矿底板突水现象提出的一个新的机制,目前还处于初步讨论阶段,以期为认识深部底板突水机制和防控提供一定的指导。

关键词：采矿工程水锤突水效应递进–导升水楔作用断裂力学突水控制

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温度和骨料预湿对煤矸石砂浆流变性的影响

矿业科学学报 2024年第2期9卷 190-198页

作者：王振波范雨润左建平中国矿业大学(北京)力学与土木工程学院北京100083

矿山充填、巷道喷射等工程对施作材料的流变性要求较高。水泥基材料中的骨料类型、状态与所处的环境对砂浆流变性能有显著影响。本文以煤矸石砂代替石英砂作为水泥基材料的细骨料,研究温度与骨料预湿对砂浆流变性的影响规律及作用机理... 详细信息

矿山充填、巷道喷射等工程对施作材料的流变性要求较高。水泥基材料中的骨料类型、状态与所处的环境对砂浆流变性能有显著影响。本文以煤矸石砂代替石英砂作为水泥基材料的细骨料,研究温度与骨料预湿对砂浆流变性的影响规律及作用机理。结果表明,煤矸石砂浆的剪切应力-剪切速率关系符合Herschel-Bulkley(H-B)模型特征,流变指数大于1,稠度明显大于石英砂砂浆;煤矸石砂浆的表观黏度随温度升高而不断降低,但骨料预湿的影响不大;30℃下煤矸石砂浆的屈服应力为2.99 Pa,比10℃下提高1.45倍,预湿后则提高2.13倍;煤矸石砂浆的触变环面积大于石英砂砂浆,预湿煤矸石砂浆的触变环面积为398.4 Pa/s,干燥煤矸石砂浆则减小为283.3 Pa/s。研究结果将为煤矸石砂的合理利用、复杂环境下流变材料的设计与制备提供支撑。

关键词：砂浆煤矸石温度预湿骨料流变性

基于相场法的花岗岩弹塑性损伤模型及其细观力学行为研究

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岩石力学与工程学报 2024年第3期43卷 611-622页

作者：李明耀李绍金彭磊丁宇飞左建平中国矿业大学(北京)力学与土木工程学院北京100083 中国矿业大学(北京)煤炭精细勘探与智能开发全国重点实验室北京100083

花岗岩的细观非均质性对其损伤破坏行为有着重要影响。基于热力学原理和力与能量平衡方程,在经典相场模型框架内引入适合岩石类材料的非关联塑性本构关系,构建弹塑性相场模型,通过与解析解和试验数据对比,验证了其正确性和可靠性。在此... 详细信息

花岗岩的细观非均质性对其损伤破坏行为有着重要影响。基于热力学原理和力与能量平衡方程,在经典相场模型框架内引入适合岩石类材料的非关联塑性本构关系,构建弹塑性相场模型,通过与解析解和试验数据对比,验证了其正确性和可靠性。在此基础上,采用数字图像处理建立符合真实细观结构的花岗岩非均质数值模型,并对其三轴压缩试验进行数值模拟,在细观尺度预测其宏观力学行为以及分析岩石裂纹扩展机制。研究结果表明:通过与试验数据和传统弹脆性相场模拟结果对比,建立的基于花岗岩真实细观结构的弹塑性相场模型可以很好地捕捉其宏观非线性力学行为;花岗岩的内部裂纹的起裂、扩展以及局部应力场的分布会受到矿物颗粒的力学性质、几何形状及分布的影响。该研究方法为今后研究岩石多尺度损伤破坏问题提供一种简单有效的途径,对评价地下工程中围岩力学性质有着重要的工程实践意义。

关键词：岩石力学弹塑性相场模型数字图像处理非关联塑性本构三轴压缩裂纹扩展细观力学

定向剪切应力路径下类弱胶结软岩椭圆各向异性强度准则

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岩石力学与工程学报 2024年第5期43卷 1219-1229页

作者：刘家顺郑智勇左建平王洋生彦涛周妮辽宁工程技术大学土木工程学院辽宁阜新123000 中国矿业大学(北京)力学与建筑工程学院北京100083 中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室湖北武汉430071

地下工程开挖卸荷引起的围岩应力重分布将影响弱胶结软岩强度,导致巷道围岩产生不均匀大变形,甚至造成塌方、冒顶等安全事故。以膨润土、风积砂、石膏粉和滑石粉为原料制备类弱胶结软岩试样,利用GDS SSHCA空心圆柱扭剪仪开展主应力定向... 详细信息

地下工程开挖卸荷引起的围岩应力重分布将影响弱胶结软岩强度,导致巷道围岩产生不均匀大变形,甚至造成塌方、冒顶等安全事故。以膨润土、风积砂、石膏粉和滑石粉为原料制备类弱胶结软岩试样,利用GDS SSHCA空心圆柱扭剪仪开展主应力定向剪切试验,研究大主应力方向对弱胶结软岩应力–应变曲线、峰值应力(变)和抗剪强度的影响规律,探索主应力方向诱导的弱胶结软岩强度各向异性特征。结果表明:当0°<α<45°时(α为大主应力与竖直方向的夹角),试样产生轴向压应变和剪应变,且随着α的增加,试样轴向应变占比逐渐减小,剪应变占比逐渐增加;当α=45°时,试样以剪应变为主,并伴随体积扩容现象;当45°<α<90°时,试样受侧向挤压产生轴向拉应变与剪应变。当0°≤α≤30°时,峰值剪应力比(τ_(zθ)/p’)max随α的增加逐渐增大;而当30°<α≤90°时,(τ_(zθ)/p’)max则随着α的增加逐渐减小;当α=30°时,(τ_(zθ)/p’)max=0.81,为最大值,这表明软岩具有显著的各向异性特征。基于峰值剪应力比演化特征,假设(τ_(zθ)/p’)max包络线为椭圆形,建立一个可描述弱胶结软岩各向异性的椭圆强度准则。利用三轴试验和纯剪试验确定模型参数并依据定向剪切试验结果验证模型的可靠性。研究成果可为地下工程围岩变形控制与灾害防治提供理论支撑。

关键词：岩石力学类弱胶结软岩各向异性椭圆强度准则定向剪切峰值剪应力比

巷道开挖应力旋转路径下弱胶结软岩剪应力–应变及非共轴特性研究

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岩石力学与工程学报 2024年第4期43卷 934-950页

作者：刘家顺朱开新左建平王来贵生彦涛孙铠洋辽宁工程技术大学土木工程学院辽宁阜新123000 中国矿业大学(北京)力学与建筑工程学院北京100083 辽宁工程技术大学力学与工程学院辽宁阜新123000

为探究巷道开挖引起的主应力旋转路径演化规律及其诱发的岩体变形问题,以弱胶结软岩巷道为工程背景,建立弱胶结软岩巷道开挖扰动数值计算模型,研究巷道开挖诱发的围岩主应力大小和方向演化规律,确定开挖扰动旋转应力路径试验加载状态参... 详细信息

为探究巷道开挖引起的主应力旋转路径演化规律及其诱发的岩体变形问题,以弱胶结软岩巷道为工程背景,建立弱胶结软岩巷道开挖扰动数值计算模型,研究巷道开挖诱发的围岩主应力大小和方向演化规律,确定开挖扰动旋转应力路径试验加载状态参数。开展弱胶结软岩空心扭剪试验,研究9种开挖扰动应力旋转路径下弱胶结软岩剪应力–应变–掘进距离空间曲线特征及(σ_(z)-σ_(θ))-2τ_(zθ)应力平面内的非共轴角变化规律。结果表明:随着巷道开挖,监测面位置巷道围岩底板、顶板和两帮的主应力大小和方向均发生显著变化,特别是在巷道2D范围内,发生了强烈的主应力方向旋转和应力量值突变。开挖扰动应力路径下巷道围岩剪应力–应变曲线呈现“V”,“Z”,“N”型发展形式。开挖扰动引起的主应力旋转造成了弱胶结软岩应变增量方向和应力方向的非共轴性,巷道底板、顶板和两帮扰动应力路径作用下,弱胶结软岩非共轴角最大值分别为52.8°,-22.3°和30.6°。研究成果将有助于揭示巷道开挖卸荷引起的主应力旋转路径下岩体非共轴塑性变形演化机制,提高地下工程设计水平以及灾害防治能力。

关键词：采矿工程岩体力学开挖扰动主应力量值主应力方向非共轴角

Experimental and theoretical investigation on mechanisms performance of the rock-coal-bolt(RCB)composite system

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International Journal of Mining Science and Technology 2020年第6期30卷 759-768页

作者： Genshui Wu Weijian Yu jianping zuo Shaohua Du School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China School of Resource&Environment and Safety Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Resources and Safety Engineering Central South UniversityChangsha 410083China

For coal mines,rock,coal,and rock bolt are the critical constituent materials for surrounding rock in the underground *** stability of the“rock-coal-bolt”(RCB)composite system is affected by the structure and fracture of the coal-rock *** rock bolts installed on the rock,more complex condition of the engineering stress environment will be(tensile-shear composite stress is principal).In this paper,experimental analysis and theoretical verification were performed on the RCB composite system with different *** results revealed that the failure of the rock-coal(RC)composite specimen was caused by tensile and shear *** anchoring,the reinforcement body formed inside the composite system limits the area where the crack could occur in the ***,shearing damage occurred only around the bolt,and the stress-strain curve presented a better post-peak mechanical *** mechanical mechanism of the bolt under the combined action of tension and shear stress was ***,a rock-coal-bolt tensile-shear mechanical(RCBTSM)model was *** relationship(similar to the exponential function)between the bolt tensile-shear stress and the angle was ***,the influences of the dilatancy angle and bolt diameter of the RCB composite system were also considered and *** of the bolts are subjected to the tensile-shearing action in the post-peak *** implications of these results for engineering practice indicated that the bolts of the RCB composite system should be prevented from entering the limit shearing state early.

关键词： Thin coal seam Coal and rock roadway Bolt Tension-shear failure “Rock-coal-bolt”composite system

Investigation of meso-failure behavior of rock under thermal-mechanical coupled effects based on high temperature SEM

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1855-1862页

作者： zuo jianping XIE HePing ZHOU HongWei State Key Laboratory of Coal Resources and Mining Safety China University of Mining and TechnologyBeijing 100083China Institute of Rock Mechanics and Fractals China University of Mining and TechnologyBeijing 100083China Sichuan University Chengdu 610065China

It is extremely important to study and understand the deformation behavior and strength characteristics of rocks under thermal-mechanical （TM） coupling effects. Failure behavior and strength characteristics of Pingdingshan sandstone were investigated at room temperatures up to 300℃ in an internally heated apparatus and tensile load through meso-scale laboratory experiments in this work. 33 experiments have successfully been conducted for Pingdingshan sandstone. Experimental results indicated that the tensile strength increased slowly with temperatures from 25℃ to 100℃, and then sharply jumped from 100℃ to 150℃, and finally decreased slightly with temperatures from 150℃ to 300℃. And about 150℃ is the threshold temperature of strength and thermal cracking. At low temperatures （25℃-150℃）, sandstone strength is determined by relatively weak clay cement. However, at higher temperatures （150℃-300℃）, because of the strength enhancement of clay cement, sandstone strength is controlled by both mineral particles and clay cement. The effects of cement clay, micro-cracks closing, and thermal cracking were the possible reasons for our detailed analysis. In addition, the typical fracture position maps and nominal stress-strain curves indicated that the temperature had strong effects on the failure mechanism of sandstone. The fractograph implied that the dominant fracture mechanism tended to transform from brittle at low temperatures to ductile at high temperatures.

关键词： sandstone thermal-mechanical (TM) effects meso-scale tensile strength thermal cracking fractography

Development of artemisinin drugs in the treatment of autoimmune diseases

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Science Bulletin 2016年第1期61卷 37-41页

作者： Yanwei Wu Wei Tang jianping zuo Laboratory of Immunopharmacology State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences

Artemisinin drugs are a family of sesquiterpene trioxane lactone agents originally derived from Artemisia annua L. Due to the big victory in the antimalarial battle,the 2015 Nobel Prize goes to the discoverer of artemisininbased therapy for malaria. Beyond antimalaria, artemisinin and its derivatives are also being investigated in diseases like schistosomiasis, viral infection, cancers and inflammation. Over the past decades, the anti-inflammatory and immunomodulatory effects of artemisinin drugs have been comprehensively studied. In this article, we will briefly describe the development of artemisinin drugs, especially novel artemisinin derivatives, in the treatment of autoimmune diseases.

关键词： Artemisinin - Autoimmune disease,Anti-inflammatory ,Immunosuppressive SM934