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Fracture evolution characteristics of sandstone containing double fissures and a single circular hole under uniaxial compression

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International Journal of Mining Science and Technology 2017年第3期27卷 499-505页

作者： Chen Minliang Jing Hongwen Ma Xiujun Su Haijian Du Mingrui zhu tantan State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining & Technology Xuzhou 221116 China Tianjin Traffic Science Research Institute Tianjin 300074 China JSTI GROUP Nanfing 210000 China

The uniaxial compression experiments on the sandstone samples containing double fissures and a single circular hole were carried out by using electro-hydraulic servo universal testing machine to investigate the effect of rock bridge angle β and fissure angle α on mechanical properties and evolution characteristics of *** results show that the peak strength,peak strain and elastic modulus of defected specimens decrease comparing with those for intact sample,and show a decreased trend firstly and then increase with β changing from 0° to 90°.The peak strength and elastic modulus achieve the minimum value as the rock bridge angle is 60°,while the peak strain reaches the minimum value with the rock bridge angle of 45°.The crack initiation of tested rock samples occurs firstly in stress concentration areas at tips of prefabricated fissures under uniaxial compression,and then propagates constantly and coalescences with the prefabricated *** secondary cracks initiate and propagate as well until buckling failure *** rock bridge angle has a great influence on crack initiation,coalescence,final failure mode,crack initiation stress and transfixion *** peak strength varies significantly,while the elastic modulus and peak strain change slightly,and the failure modes are also different due to the influence of fissure angle.

关键词： Double fissures A single circular hole Strength characteristics Crack propagation Failure mode

Experimental and Numerical Study on the Shear Strength and Strain Energy of Rock Under Constant Shear Stress and Unloading Normal Stress

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Computer Modeling in Engineering & Sciences 2021年第4期127卷 79-97页

作者： tantan zhu Da Huang Jianxun Chen Yanbin Luo Longfei Xu School of Highway Chang’an UniversityXi’an710064China College of Geological Engineering and Geomatics Chang’an UniversityXi’an710064China School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China

Excavation and earth surface processes(e.g.,river incision)always induce the unloading of stress,which can cause the failure of *** study the shear mechanical behavior of a rock sample under unloading normal stress conditions,a new stress path for direct shear tests was proposed to model the unloading of stress caused by excavation and other *** effects of the initial stresses(i.e.,the normal stress and shear stress before unloading)on the shear behavior and energy conversion were investigated using laboratory tests and numerical *** shear strength of a rock under constant stress or under unloading normal stress conforms to the Mohr Coulomb *** the initial normal stress increases,the cohesion decreases linearly and the tangent of the internal friction angle increases *** with the results of the tests under constant normal stress,the cohesions of the rock samples under unloading normal stress are smaller and their internal friction angles are larger.A strength envelope surface can be used to describe the relationship between the initial stresses and the failure normal *** dilatancy can decrease the total energy of the direct shear test under constant normal stress or unloading normal stress,particularly when the stress levels(the initial stresses in the test under unloading normal stress or the normal stress in the test under constant normal stress)are *** ratio of the dissipated energy to the total energy at the moment failure occurs decreases exponentially with increasing initial *** direct shear test under constant normal stress can be considered to be a special case of a direct shear test under unloading normal stress with an unloading amount of zero.

关键词： Unloading normal stress direct shear test strain energy energy conversion

Cable-truss supporting system for gob-side entry driving in deep mine and its application

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International Journal of Mining Science and Technology 2016年第5期26卷 885-893页

作者： Yin Qian Jing Hongwen Dai Dapeng zhu tantan Zhao Honghui Meng Bo State Key Laboratory for Geomechanics ＆ Deep Underground Engineering China University of Mining ＆ Technology Xuzhou 221116 China Shanghai Underground Space Architectural Design ＆ Research Institute Shanghai 200020 China East China Environmental ＆ Geotechnical Engineering Branch China Petroleum Qingdao 266000 China

In order to solve the large deformation controlling problem for surrounding rock of gob-side entry driving under common cable anchor support in deep mine, site survey, physical modeling experiment, numerical simulation and field measurement were synthetically used to analyze the deformation and failure characteristics of surrounding rock. Besides, applicability analysis, prestress field distribution characteristics of surrounding rock and the control effect on large deformation of surrounding rock were also further studied for the gob-side entry driving in deep mine using the cable-truss supporting system. The results show that, first, compared with no support and traditional bolt anchor support, roof cable-truss system can effectively restrain the initiation and propagation of tensile cracks in the roof surrounding rock and arc shear cracks in the two sides, moreover, the broken development of surrounding rock, roof separation and extrusion deformation between the two sides of the roadway are all controlled; second, a prestressed belt of trapezoidal shape is generated in the surrounding rock by the cable-truss supporting system, and the prestress field range is wide. Especially, the prestress concentration belt in the shallow surrounding rock can greatly improve the anchoring strength and deformation resisting capability of the rock stratum;third, an optimized support system of ‘‘roof and side anchor net beam, roof cable-truss supporting system and anchor cable of the narrow coal pillar" was put forward, and the support optimization design and field industrial test were conducted for the gob-side entry driving of the working face 5302 in Tangkou Mine, from which a good supporting effect was obtained.

关键词： Deep mine Gob-side entry driving Cable-truss supporting system Deformation and failure Stability

Physical and mechanical properties of sandstone containing a single fissure after exposure to high temperatures

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International Journal of Mining Science and Technology 2016年第2期26卷 319-325页

作者： zhu tantan Jing Hongwen Su Haijian Yin Qian Du Mingrui Han Guansheng State Key Laboratory for Geomechanics & Deep Underground Engineering China University of Mining & Technology

In order to investigate the physical and mechanical properties of sandstone containing fissures after exposure to high temperatures,fissures with different angles α were prefabricated in the plate sandstone samples,and the processed samples were then heated at 5 different *** uniaxial compression was conducted to analyze the change rules of physical properties of sandstone after exposure to high temperature,and the deformation,strength and failure characteristics of sandstone containing *** results show that,with increasing temperature,the volume of sandstone increases gradually while the quality and density decrease gradually,and the color of sandstone remains basically unchanged while the brightness increases markedly when the temperature is higher than 585 ℃;the peak strength of sandstone containing fissures first decreases then increases when the temperature is between 25℃and 400℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature,and the mechanical properties of sandstone show obvious deterioration after 400 ℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature;with increasing angle αof the fissure,the evolution characteristics of the macro-mechanical parameters of sandstone are closely related to the their own mechanical *** the temperature is 800 ℃,the correlation between the peak strength and average modulus of sandstone and the angle α of the fissure is obviously *** failure modes of sandstone containing fissures after high temperature exposure are of three different kinds including:tensile crack failure,tensile and shear cracks mixed failure,and shear crack *** and shear crack mixed failure occur mainly at low temperatures and small angles;tensile crack failure occurs at high temperatures and large angles.

关键词：物理力学性质裂隙砂岩高温度峰值强度剪切破坏宏观力学参数峰值应变力学性能

应力-冻融耦合作用下砂岩变形与损伤特征研究

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岩石力学与工程学报 2023年第2期42卷 342-351页

作者：朱谭谭李昂黄达宗西垒马福旺长安大学公路学院陕西西安710064 长安大学地质工程与测绘学院陕西西安710064 河北工业大学土木与交通学院天津300401

寒冷地区工程岩体承受应力和冻融循环的共同作用。在长期应力-冻融耦合作用下,岩石力学性能会产生显著弱化,造成工程岩体灾害。为了研究应力-冻融耦合作用下砂岩的变形和宏细观损伤特征,首先采用砂岩试样开展冻融循环试验,研究无应力作... 详细信息

寒冷地区工程岩体承受应力和冻融循环的共同作用。在长期应力-冻融耦合作用下,岩石力学性能会产生显著弱化,造成工程岩体灾害。为了研究应力-冻融耦合作用下砂岩的变形和宏细观损伤特征,首先采用砂岩试样开展冻融循环试验,研究无应力作用下砂岩冻融循环过程中的冻融变形规律。然后提出一种基于颗粒流和颗粒膨胀的岩石冻融循环数值模拟方法,并采用该方法开展应力作用下岩石冻融循环数值模拟,研究轴向应力作用下岩石冻融过程中的变形和破裂演化规律。研究结果表明:无轴向应力时,随着冻融循环次数的增大,砂岩的轴向和径向应变先增大后基本保持不变;冻融循环过程中砂岩试样轴向和径向应变存在显著差异,试样径向应变大于轴向应变,砂岩试样轴向和径向应变的差异随着冻融循环次数的增多先增大后减小;轴向应力不为0时,试样轴向应变随冻融循环次数的增大逐渐减小,径向应变随冻融循环次数的增大逐渐增大;在冻胀力作用下,试样表面附近的裂纹密度大于试样内部的裂纹密度;冻融循环过程中,轴向应力会抑制裂纹沿与试样轴线夹角较大的方向起裂和扩展;冻融循环过程中,试样内的破坏以拉伸破坏为主;基于颗粒流和颗粒膨胀的数值模拟方法能够较好的模拟冻融循环过程中砂岩的冻融变形和破裂演化规律。

关键词：岩石力学应力-冻融耦合轴向应力冻胀变形颗粒流冻胀损伤

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西部侏罗系软岩巷道松动圈演化机理模型试验

中国矿业大学学报 2014年第6期43卷 1003-1010,1037页

作者：孟波靖洪文朱谭谭中国矿业大学力学与建筑工程学院江苏徐州221116 中国矿业大学深部岩土力学与地下工程国家重点实验室江苏徐州221116

采用大比例尺物理模型试验的研究方法,分析了西部侏罗系软岩巷道松动圈形成及其发展过程中围岩破裂与应力演化规律,对松动圈形成及稳定机理进行了探讨.结果表明,巷道开挖后围岩在应力差作用下发生塑性剪切变形,塑性剪应变集中分布,形成... 详细信息

采用大比例尺物理模型试验的研究方法,分析了西部侏罗系软岩巷道松动圈形成及其发展过程中围岩破裂与应力演化规律,对松动圈形成及稳定机理进行了探讨.结果表明,巷道开挖后围岩在应力差作用下发生塑性剪切变形,塑性剪应变集中分布,形成宏观滑移迹线.滑移迹线交汇联通形成的剪切楔体在后续压力作用下向巷道内部旋转滑移及二次破坏是围岩碎胀变形的主要原因.剪切楔体之间相互阻挡和挤压,在松动圈内部形成空间上的结构效应,使围岩具有一定的残余承载能力而不发生垮塌.根据剪切楔体的形成和运动情况,将松动圈发展演化过程分为剪切滑移迹线形成期、楔体形成期、块体滑移期、块体塌落挤密期4个阶段.在松动圈Ⅲ期,甚至Ⅲ期之前即对浅部围岩施加锚杆、注浆等支护手段提高浅部围岩残余强度对巷道稳定性控制具有重要意义.

关键词：松动圈演化过程剪切滑移结构效应塑性剪应变

法向卸荷条件下含单裂隙砂岩剪切强度与破坏特征试验研究

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岩石力学与工程学报 2019年第7期38卷 1297-1306页

作者：黄达郭颖泉朱谭谭张永发河北工业大学土木与交通学院天津300401 重庆大学煤矿灾害动力学与控制国家重点实验室重庆400044

在地下工程及边坡开挖和河谷下切等人为和自然因素作用下,岩体应力将沿至少某一个方向卸荷,造成复杂的岩体应力重新分布。这种卸荷易诱发岩体工程灾变,其中法向应力卸荷诱发岩体剪切破坏尤为突出。采用法向应力逐渐卸荷而剪切应力保持... 详细信息

在地下工程及边坡开挖和河谷下切等人为和自然因素作用下,岩体应力将沿至少某一个方向卸荷,造成复杂的岩体应力重新分布。这种卸荷易诱发岩体工程灾变,其中法向应力卸荷诱发岩体剪切破坏尤为突出。采用法向应力逐渐卸荷而剪切应力保持恒定的直剪试验方法,模拟开挖卸荷诱发岩体剪切破坏的力学机制。研究法向应力卸荷条件下,裂隙与剪切方向的夹角(后面简称夹角)及应力水平对单裂隙砂岩试样剪切变形、强度及破裂演化的影响规律。随着夹角从0°向180°增加,破坏模式依次表现为剪切破坏、张拉破坏、张剪混合破坏及剪切破坏的过渡。卸荷过程中法向位移和剪切位移均随初始法向应力的增大逐渐增大,而随初始剪应力的增大均逐渐减小。卸荷过程中法向位移随夹角的增大呈现先减小后增大的变化,而剪切位移对夹角不敏感。破坏时法向应力卸荷量随初始法向应力的增大逐渐增大,随初始剪应力的增大逐渐减小,随夹角的增大先减小后增大,夹角为60°时试样最容易发生破坏。通过对破裂面的应力状态分析,从力学机制的角度解释了破坏模式与夹角的相关性。研究成果丰富了卸荷岩体力学基础理论,为岩体工程开挖灾害防治提供理论支撑。

关键词：岩石力学裂隙岩体法向卸荷直接剪切裂隙夹角破裂模式

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高温后花岗岩断裂特性的加载速率效应研究

中国矿业大学学报 2015年第4期44卷 597-603页

作者：尹乾靖洪文苏海健朱谭谭中国矿业大学深部岩土力学与地下工程国家重点实验室江苏徐州221116

为考察温度和加载速率对花岗岩断裂特性的影响规律,对25～800℃之间5种温度水平高温后的中心直裂纹花岗岩巴西圆盘试样分别进行了5种加载速率下的室内劈裂试验.结果表明：圆盘的荷载-位移曲线呈现典型的脆性特征,但随温度的升高,脆性特... 详细信息

为考察温度和加载速率对花岗岩断裂特性的影响规律,对25～800℃之间5种温度水平高温后的中心直裂纹花岗岩巴西圆盘试样分别进行了5种加载速率下的室内劈裂试验.结果表明：圆盘的荷载-位移曲线呈现典型的脆性特征,但随温度的升高,脆性特征逐渐弱化,与加载速率相比,温度对曲线的发展趋势影响较大;随温度的升高,花岗岩断裂韧度逐渐减小且在400℃时发生突变;不同温度条件下断裂韧度随加载速率的增大逐渐增加,但增加幅度逐渐减小最终趋于平缓,具有明显的加载速率效应,提出了相应的经验公式KIC=A＋B/（v＋C）,其中随温度的升高,参数A逐渐降低,参数B波动较小,而参数C逐渐增大,同时获得了花岗岩材料断裂韧度的下限值KIC0。

关键词：高温断裂韧度加载速率中心直裂纹巴西圆盘劈裂试验

含预制椭圆形孔洞砂岩强度及破坏特征试验研究

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中国矿业大学学报 2016年第6期45卷 1164-1171页

作者：杜明瑞靖洪文苏海健朱谭谭中国矿业大学深部岩土力学与地下工程国家重点实验室江苏徐州221116

通过对含预制椭圆形孔洞板状砂岩试样进行单轴压缩试验,研究了椭圆长轴与短轴之比k及石膏充填作用对岩样强度和破坏特征的影响规律.研究表明,含孔洞岩样的强度和变形参数相对于完整试样均有不同程度的降低,而石膏充填后试样的峰值强度... 详细信息

通过对含预制椭圆形孔洞板状砂岩试样进行单轴压缩试验,研究了椭圆长轴与短轴之比k及石膏充填作用对岩样强度和破坏特征的影响规律.研究表明,含孔洞岩样的强度和变形参数相对于完整试样均有不同程度的降低,而石膏充填后试样的峰值强度和弹性模量均有所提高,但峰值应变无明显变化规律;无论充填与否,试样峰值强度均随着k值的增加均呈指数形式降低;充填作用对岩样宏观破坏模式无明显影响,岩样最终均以剪切破坏为主,主破裂面沿对角线分布;相对于无充填的岩样,石膏充填后的岩样破坏时宏观裂隙数目增多,破坏程度加剧.

关键词：岩石力学椭圆形孔洞充填作用力学参数破坏模式