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Cracks coalescence mechanism and cracks propagation paths in rock-like specimens containing pre-existing random cracks under compression 被引量:18
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作者 Hadi Haeri Kourosh Shahriar +1 位作者 Mohammad Fatehi Marji Parviz Moarefvand 《Journal of Central South University》 SCIE EI CAS 2014年第6期2404-2414,共11页
The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks (flaws) was modeled experimentally using specially made rock-like specim... The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks (flaws) was modeled experimentally using specially made rock-like specimens from Portland Pozzolana Cement (PPC). The breakage process of the specimens was studied by inserting single and double flaws with different inclination angles at the center and applying uniaxial compressive stress at both ends of the specimen. The first crack was oriented at 50&#176; from the horizontal direction and kept constant throughout the analysis while the orientation of the second crack was changed. It is experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of uniaxial compressive loading. The secondary cracks may also be produced in form of quasi-coplanar and/or oblique cracks in a stable manner. The secondary cracks may eventually continue their propagation in the direction of maximum principle stress. These experimental works were also simulated numerically by a modified higher order displacement discontinuity method and the cracks propagation and cracks coalescence were studied based on Mode I and Mode II stress intensity factors (SIFs). It is concluded that the wing cracks initiation stresses for the specimens change from 11.3 to 14.1 MPain the case of numerical simulations and from 7.3 to 13.8 MPa in the case of experimental works. It is observed that cracks coalescence stresses change from 21.8 to 25.3 MPa and from 19.5 to 21.8 MPa in the numerical and experimental analyses, respectively. Comparing some of the numerical and experimental results with those recently cited in the literature validates the results obtained by the proposed study. Finally, a numerical simulation was accomplished to study the effect of confining pressure on the crack propagation process, showing that the SIFs increase and the crack initiation angles change in this case. 展开更多
关键词 crack propagation crack coalescence rock-like specimen numerical simulation experiment
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A damage constitutive model of rock-like materials containing a single crack under the action of chemical corrosion and uniaxial compression 被引量:11
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作者 PAN Ji-liang CAI Mei-feng +1 位作者 LI Peng GUO Qi-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第2期486-498,共13页
To describe the deformation and strength characteristics of the corroded rock-like specimens containing a single crack under uniaxial compression,a damage constitutive model combining hydro-chemical damage with coupli... To describe the deformation and strength characteristics of the corroded rock-like specimens containing a single crack under uniaxial compression,a damage constitutive model combining hydro-chemical damage with coupling damage of micro-flaws and macro-cracks is proposed.Firstly,based on phenomenological theory,the damage variable of the rock-like specimens subjected to water environment erosion and chemical corrosion is obtained.Secondly,a coupled damage variable for cracked rock-like specimens is derived based on the Lemaitre strain equivalence hypothesis,which combines the Weibull statistical damage model for micro-flaws and the fracture mechanics model for a macro single crack.Then,considering the residual strength characteristics of the rock-like materials,the damage variable is modified by introducing the correction coefficient,and the damage constitutive model of the corroded rock-like specimens with a single crack under uniaxial compression is established.The model is verified by comparing the experimental stress−strain curves,and the results are in good agreement with those provided in the literature.Finally,the correction coefficient of the damage variable proposed in this paper is discussed.The damage constitutive model developed in this paper provides an effective method to describe the stress−strain relationship and residual strength characteristics of the corroded rock-like specimens with a single crack under uniaxial compression. 展开更多
关键词 rock-like material single-cracked rock damage constitutive model hydro-chemical erosion residual strength damage variable
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Failure characteristics and its influencing factors of rock-like material with multi-fissures under uniaxial compression 被引量:10
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作者 PU Cheng-zhi CAO Ping 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第1期185-191,共7页
The compression test on rock-like specimens with prefabricated closed multi-fissures made by pulling out the embedded metal inserts in the precured period was done on the servo control uniaxial loading instrument. The... The compression test on rock-like specimens with prefabricated closed multi-fissures made by pulling out the embedded metal inserts in the precured period was done on the servo control uniaxial loading instrument. The influence of fissure inclination angle and distribution density on the failure characteristics of fissure bodies was researched. It was found that, the fissure inclination angle was the major influencing factor on the failure modes of fissure bodies. The different developmental states of micro-cracks would appear on specimens under different fissure inclination angles. However, the influence of fissure distribution density on the failure mode of fissure bodies was achieved by influencing the transfixion pattern of fissures. It was shown by the sliding crack model that, the effective shear, which drove the relative sliding of the fissure, was a function of fissure inclination angle and friction coefficient of the fissure surface. The strain-softening model of fissure bodies was established based on the mechanical parameters that were obtained by the test of rock-like materials under the same experimental condition. And the reliability of experimental results was identified by using this model. 展开更多
关键词 rock-like material prefabricated fissure uniaxial compression sliding crack model strain-softening model
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Non-parallel double-crack propagation in rock-like materials under uniaxial compression 被引量:4
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作者 Weidong Pan Xin Wang +2 位作者 Qiming Liu Yongkang Yuan Baodong Zuo 《International Journal of Coal Science & Technology》 EI 2019年第3期372-387,共16页
Coalescence among fractures would have influence on the stability of rock masses. Deep understanding of mechanical behavior of fractured rock masses is an important mean to identify failure mechanism of geological dis... Coalescence among fractures would have influence on the stability of rock masses. Deep understanding of mechanical behavior of fractured rock masses is an important mean to identify failure mechanism of geological disaster. In this study, crack propagation processing was studied through loading pre-fractured specimens of concrete block, termed as rock-like material, in uniaxial compression tests. New non-parallel double-crack geometry was introduced to observe crack coalescence. The flaw combinations are different from the normally used flaw configurations. In addition, ultrasonic detection tests were performed on the test blocks. The stress and strain data of these tests and characteristic parameters of sound wave were recorded. The stress-strain curves of each test block under the uniaxial compression test were drawn, relations among deformation characteristics and crack angle of the crack specimens, and their overall strength were analyzed. It is found that strength of the specimen decreases as crack inclination increases under two crack inclinations. The highest uniaxial compressive strength is found in the specimen with the cracks at the same angle in different directions. Based on description of the crack initiation location, crack surface and the ultimate failure patterns, failure modes of eight subtype for test blocks are divided into three categories. It is expected that the study results could be beneficial for engineering application of jointed rock masses. 展开更多
关键词 rock-like material Non-parallel DOUBLE cracks CRACK-PROPAGATION path UNIAXIAL compression test
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An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression 被引量:9
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作者 Yan-Hua Huang Sheng-Qi Yang +2 位作者 Wen-Ling Tian Wei Zeng Li-Yuan Yu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第3期442-455,共14页
Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalesce... Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel fissures.In the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures(a horizontal fissure and an inclined fissure) were created by inserting steel during molding the model specimen.Then all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servocontrolled testing system. The peak strength and Young's modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0?to 75?.In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation process.Moreover, acoustic emission(AE) monitoring technique was also used to obtain the AE evolution characteristic of prefissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up: when a new crack was initiated or a crack coalescence occurred, thecorresponding axial stress dropped in the axial stress–time curve and a big AE event could be observed simultaneously.Finally, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures. 展开更多
关键词 rock-like material Two unparallel fissures Mechanical parameters Crack evolution Acoustic emission(AE)
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Experimental study of polyurethane foam reinforced soil used as a rock-like material 被引量:1
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作者 Eren Komurlu Ayhan Kesimal 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2015年第5期566-572,共7页
In this study, p o ly u reth an e foam ty p e th e rm o se t polym erizing, d u e to chem ical reaction b e tw e e n itsliquid ingredients, w as teste d as b in d e r afte r solidifying and th e n a rock-like m ateria... In this study, p o ly u reth an e foam ty p e th e rm o se t polym erizing, d u e to chem ical reaction b e tw e e n itsliquid ingredients, w as teste d as b in d e r afte r solidifying and th e n a rock-like m aterial m ixing w ith asandy silt ty p e soil w as prep ared . The uniaxial com pressive stren g th s (UCSs) o f p o ly u reth an e foamreinforced soil specim ens w ere d e term in ed for different p o ly u reth an e ratios in th e m ixture. A dditionally,a series o f te sts o n slake durability, im pact value, freezing-th aw in g resistance, and ab rasio n resistance ofp o ly u reth an e reinforced soil (PRS) m ix tu re w as co n d u cted . The UCS values over 3 M Pa w ere m easuredfrom th e PRS specim ens. The testin g results show ed th a t tre a te d soil can econom ically b ecom e adesirable rock-like m aterial in term s o f slake d u ra b ility a n d resistances ag ain st freezing-thaw ing, im pacteffect an d abrasion. As a n o th e r ch aracteristic o f th e rock-like m aterial m ade w ith p o ly u reth an e foam,u n it volum e w eig h t w as found to be q uite low er th a n th o se o f n atu ral rock m aterials. 展开更多
关键词 Polyurethane reinforced soil(PRS) rock-like material POLYURETHANE Environmental resistance of rocks Rock testing
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STUDY ON DAMAGE BIFURCATION AND INSTABILITY OF ROCK-LIKE MATERIALS 被引量:1
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作者 Luan Maotian Wang Zhongchang Yang Qing 《Acta Mechanica Solida Sinica》 SCIE EI 2006年第3期275-282,共8页
The critical bifurcation orientation and its corresponding hardening modulus for rock-like geomaterials are derived by considering the effect of stiffness degradation and volumetric dilatancy under the assumption of i... The critical bifurcation orientation and its corresponding hardening modulus for rock-like geomaterials are derived by considering the effect of stiffness degradation and volumetric dilatancy under the assumption of isotropic damage. The dependency of the localized orientation on the degree of damage and initial Poisson's ratio of rock is examined and the bifurcation behavior of the uniaxial compression sample under the plane-stress condition is compared with that under plane-strain condition. It is shown that the localization orientation angle intimately depends on both the initial Poisson's ratio and degree of damage for the rock sample under the uniaxial compression condition. As the initial Poisson's ratio or degree of damage increases, the orientation angle of the plane on which localization tends to be initiated gets to decrease. At the same time, the localization orientation angle of a rock sample under the plane-stress condition is larger than that under the plane-strain condition. 展开更多
关键词 damage degradation maximum hardening modulus BIFURCATION orientation of localization rock-like materials
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Mechanism of stress distribution and failure around two different shapes of openings within fractured rock-like materials 被引量:1
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作者 FAN Xiang YANG Zhi-jun +2 位作者 HONG Ming YU Hao XIE Yong-li 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第6期1916-1932,共17页
The complexity of a rock masses structure can lead to high uncertainties and risk during underground engineering construction.Laboratory tests on fractured rock-like materials containing a tunnel were conducted,and tw... The complexity of a rock masses structure can lead to high uncertainties and risk during underground engineering construction.Laboratory tests on fractured rock-like materials containing a tunnel were conducted,and twodimensional particle flow models were established.The principal stress and principal strain distributions surrounding the four-arc-shaped and inverted U-shaped tunnels were investigated,respectively.Numerical results indicated that the dip angle combination of preexisting fractures directly affects the principal stress,principal strain distribution and the failure characteristics around the tunnel.The larger the absolute value of the preexisting fracture inclination angle,the higher the crushing degree of compression splitting near the hance and the larger the V-shaped failure zone.With a decrease in the absolute value of the preexisting fracture inclination angle,the compressive stress concentration of the sidewall with preexisting fractures gradually increases.The types of cracks initiated around the four-arc-shaped tunnel and the inverted U-shape tunnel are different.When the fractures are almost vertical,they have a significant influence on the stress of the sidewall force of the four-arc-shaped tunnel.When the fractures are almost horizontal,they have a significant influence on the stress of the sidewall of the inverted U-shaped tunnel.The findings provide a theoretical support for the local strengthening design of the tunnel supporting structure. 展开更多
关键词 TUNNEL fractured rock-like material 2D particle flow code crack initiation stress distribution
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Identification of the Discrete Element Model Parameters for Rock-Like Brittle Materials
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作者 Rui Chen Yong Wang +3 位作者 Ruitao Peng Shengqiang Jiang Congfang Hu Ziheng Zhao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第5期717-737,共21页
An inverse method for parameters identification of discrete element model combined with experiment is proposed.The inverse problem of parameter identification is transmitted to solve an optimization problem by minimiz... An inverse method for parameters identification of discrete element model combined with experiment is proposed.The inverse problem of parameter identification is transmitted to solve an optimization problem by minimizing the distance between the numerical calculations and experiment responses.In this method,the discrete element method is employed as numerical calculator for the forward problem.Then,the orthogonal experiment design with range analysis was used to carry out parameters sensitivity analysis.In addition,to improve the computational efficiency,the approximate model technique is used to replace the actual computational model.The intergeneration projection genetic algorithm(IP-GA)is employed as the optimization algorithm.Consequently,the parameters of the discrete element model are determined.To verify the effectiveness and accuracy of the inverse results,the comparisons of shape deviation experiments with discrete element simulations are provided.It indicates that the effective and reliable discrete element model parameters can be quickly obtained through several sets of experimental data.Hence,this inverse method can be applied more widely to determine the parameters of discrete element model for other materials. 展开更多
关键词 Discrete element model parameter determination rock-like materials IP-GA inverse method.
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Application of the expanded distinct element method for the study of crack growth in rock-like materials under uniaxial compression 被引量:5
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作者 Lei YANG Yujing JIANG +2 位作者 Bo LI Shucai LI Yang GAO 《Frontiers of Structural and Civil Engineering》 SCIE EI 2012年第2期121-131,共11页
The expanded distinct element method(EDEM)was used to investigate the crack growth in rock-like materials under uniaxial compression.The tensile-shear failure criterion and the Griffith failure criterion were implante... The expanded distinct element method(EDEM)was used to investigate the crack growth in rock-like materials under uniaxial compression.The tensile-shear failure criterion and the Griffith failure criterion were implanted into the EDEM to determine the initiation and propagation of pre-existing cracks,respectively.Uniaxial compression experiments were also performed with the artificial rock-like samples to verify the validity of the EDEM.Simulation results indicated that the EDEM model with the tensile-shear failure criterion has strong capabilities for modeling the growth of pre-existing cracks,and model results have strong agreement with the failure and mechanical properties of experimental samples.The EDEM model with the Griffith failure criterion can only simulate the splitting failure of samples due to tensile stresses and is incapable of providing a comprehensive interpretation for the overall failure of rock masses.Research results demonstrated that sample failure primarily resulted from the growth of single cracks(in the form of tensile wing cracks and shear secondary cracks)and the coalescence of two cracks due to the growth of wing cracks in the rock bridge zone.Additionally,the inclination angle of the pre-existing crack clearly influences the final failure pattern of the samples. 展开更多
关键词 expanded distinct element method(EDEM) crack growth rock-like material tensile-shear failure criterion Griffith failure criterion mechanical and failure behavior
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类岩石试件三轴扰动破坏特性试验研究
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作者 王军 朱传根 +2 位作者 李勋 王波 张艺腾 《采矿与岩层控制工程学报》 EI 北大核心 2024年第2期11-24,共14页
为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试... 为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试件扰动破坏机理。研究结果表明:(1)试件在不同围压下均存在一个阈值强度,轴向荷载超过阈值强度后,轴向变形对扰动变得敏感,再次施加扰动会引起试件显著变形,当轴向荷载低于阈值强度时,变形对扰动不敏感。阈值强度与极限强度的比值可以反映试件的抗扰动能力,随着围压增大,该比值呈现逐步递减的规律,说明高围压下试件抗扰动能力下降,对扰动作用更敏感。(2)扰动作用下类岩石试件存在弱化效应,如常规三轴10MPa围压下试件表现出腰鼓破坏,而受扰动作用后,试件呈现斜切脆性破坏,与常规三轴5MPa围压下破坏形态相近。(3)岩石试件在高应力作用下进入塑性流动状态,内部颗粒重新排列,内部小孔隙与大孔隙的占比减少,而中孔隙的占比显著增多,试件内部孔隙率整体降低。 展开更多
关键词 类岩石试件 三轴扰动 阈值强度 破坏形态 核磁共振
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强度比对类复合岩样冲击破碎特征的影响
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作者 温森 黄睿智 +1 位作者 孔庆梅 李胜 《科学技术与工程》 北大核心 2024年第6期2495-2502,共8页
为了保证复合地层中施工效率及工程安全,揭示动荷载作用下复合岩层的力学特征,通过分离式霍普金森压杆对三种不同强度比的类复合岩样进行动态巴西劈裂试验,基于破碎分形理论,探究强度比、应变率、入射角对类复合岩样的破碎程度及能耗特... 为了保证复合地层中施工效率及工程安全,揭示动荷载作用下复合岩层的力学特征,通过分离式霍普金森压杆对三种不同强度比的类复合岩样进行动态巴西劈裂试验,基于破碎分形理论,探究强度比、应变率、入射角对类复合岩样的破碎程度及能耗特性的影响。试验结果表明:层理面倾角对类复合岩样破碎形态有较大影响,当应变率为146.36 s^(-1)时,沿层理面加载试样易发生劈裂拉伸破坏,且强度比越低试样破坏所需吸收的能量越少;当入射角为0°时,类复合岩样分形维数随着强度比的增大而增大,但当入射角为90°时强度比为1.5的复合岩样分形维数最大;类复合岩样吸收的能量主要用于裂纹扩展,单位体积内试样吸收的能量越大,试样越破碎,即类复合岩样分形维数与能耗密度呈正相关。 展开更多
关键词 分离式霍普金森压杆 类复合岩样 强度比 分形维数 能耗密度
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不同控制方式和卸荷应力路径下类岩石节理剪切强度特征研究
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作者 孙杰豪 郭保华 +2 位作者 程胜锦 田世轩 陈岩 《岩土力学》 EI CAS CSCD 北大核心 2024年第7期2061-2071,2116,共12页
为研究不同控制方式和卸荷应力路径下岩石节理失稳剪切强度特征,借助RDS-200型岩石节理剪切试验系统开展了2种控制方式和3种卸荷应力路径下的类岩石节理直剪试验。结果表明:(1)采用应力控制方式进行切向加卸载时,各剪切加卸载路径下,节... 为研究不同控制方式和卸荷应力路径下岩石节理失稳剪切强度特征,借助RDS-200型岩石节理剪切试验系统开展了2种控制方式和3种卸荷应力路径下的类岩石节理直剪试验。结果表明:(1)采用应力控制方式进行切向加卸载时,各剪切加卸载路径下,节理剪切应力-时间曲线多存在失稳跌落现象,剪切应力-位移曲线失稳后多表现为折线形式。(2)与采用应力控制方式进行切向加载的试样结果相比,采用位移控制方式进行切向加载、采用应力控制方式进行法向卸载并保持剪切应力恒定、采用应力控制方式进行法向卸载和切向加载、采用应力控制方式同时进行法向和切向卸载的试样失稳剪切强度均有所降低;节理黏聚力减小百分比平均值为36.07%,而内摩擦角变化范围仅在4.12%以内,所以黏聚力降低是节理失稳剪切强度降低的主要原因。(3)以采用应力控制方式进行切向加载试样的拟合摩尔-库仑公式为基准,位移控制方式或其他采用应力控制方式的加卸载应力路径下试样失稳剪切强度的相对误差平均值最大可达55.78%。经引入黏聚力修正系数k对摩尔-库仑准则进行修正后,相对误差平均值的最大值减小到5.23%,说明对经受位移控制方式或采用应力控制方式的其他加卸载应力路径的工程节理来说,进行黏聚力的折减修正是必要和可行的。研究结果对不同控制方式及卸荷应力路径下岩体节理剪切承载能力的准确估计具有一定参考价值。 展开更多
关键词 岩石力学 控制方式 应力路径 类岩石节理 直剪试验 剪切强度
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双轴加载下成组裂隙参数对类岩石试件力学性质的影响规律
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作者 谢凯 唐彬 +2 位作者 程松 赵能 王逸洋 《佳木斯大学学报(自然科学版)》 CAS 2024年第2期92-96,共5页
煤矿深部地层岩巷围岩裂隙分布复杂,裂隙参数对岩体力学性能影响较大。为研究深部地层裂隙岩体在掘进扰动条件下的破坏规律与力学性能,制备不同裂隙倾角和长度的成组裂隙类岩石试件,开展模拟煤矿深部巷道掘进扰动的双轴加载试验,研究类... 煤矿深部地层岩巷围岩裂隙分布复杂,裂隙参数对岩体力学性能影响较大。为研究深部地层裂隙岩体在掘进扰动条件下的破坏规律与力学性能,制备不同裂隙倾角和长度的成组裂隙类岩石试件,开展模拟煤矿深部巷道掘进扰动的双轴加载试验,研究类岩石试件力学特性及其影响因素。研究结果表明:成组裂隙试件强度受预制裂隙的倾角影响明显,当预制裂隙倾角为30°~45°时,试件的起裂应力和峰值应力为最小值,当裂隙倾角为90°时,试件的起裂应力和峰值应力最大。在双轴固定比例加载的条件下,裂隙倾角和长度均会对试件的强度产生影响,其中裂隙倾角对试件强度的影响最为明显,裂隙长度的影响较小。 展开更多
关键词 成组裂隙 双轴加载 类岩石试件 力学特性 破裂模式
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伸展背景下的埃达克质岩:黑龙江呼玛地区早白垩世侵入岩的年代学和地球化学特征 被引量:1
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作者 张坤 史冬岩 +2 位作者 常翔鲲 朴星海 王伟东 《吉林大学学报(地球科学版)》 CAS CSCD 北大核心 2024年第4期1248-1263,共16页
为理清大兴安岭兴安地块中生代岩体的岩石成因及构造背景,本文通过岩石学、年代学、全岩地球化学等方法,对大兴安岭东北部的黑龙江省呼玛地区早白垩世侵入岩进行了研究。结果显示:研究区早白垩世中性侵入岩为钙碱性-高钾钙碱性系列准铝... 为理清大兴安岭兴安地块中生代岩体的岩石成因及构造背景,本文通过岩石学、年代学、全岩地球化学等方法,对大兴安岭东北部的黑龙江省呼玛地区早白垩世侵入岩进行了研究。结果显示:研究区早白垩世中性侵入岩为钙碱性-高钾钙碱性系列准铝质-弱过铝质岩石,成岩时间在(121.3±1.2)~(118.7±0.9)Ma之间,稀土元素配分曲线显示为右倾模式,Eu微弱正异常(0.98~1.11),富集K、Sr、Ba等大离子亲石元素,亏损Nb、Ta、Ti、P等高场强元素。岩石同时具有高的Sr/Y(57.66~145.76)、LaN/YbN(11.66~29.52)和较高的Mg^(#)(50.93~57.63)、w(Cr)(77.00×10^(-6)~92.60×10^(-6))、w(Ni)(23.20×10^(-6)~32.60×10^(-6))值,显示出埃达克质岩特征。综合本次研究认为该期侵入岩主要形成于蒙古-鄂霍茨克洋闭合后的伸展环境,由加厚下地壳导致的岩石圈拆沉,软流圈幔源岩浆上涌形成埃达克质岩石。 展开更多
关键词 呼玛地区 花岗岩 锆石U-PB测年 地球化学 埃达克质岩
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基于改进接触模型的类岩石材料裂纹扩展分析
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作者 丁小彬 谢宇轩 施钰 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第8期146-158,共13页
为了探究复杂应力状态下岩体内缺陷(裂隙)的扩展与贯通机理,基于三维离散元软件(PFC3D)和改进的平行黏结模型(IPBM),模拟了双轴压缩试验中含双预制裂纹类岩石材料的裂纹扩展过程。通过逼近实验试件抗压强度、抗拉强度和弹性模量的宏观... 为了探究复杂应力状态下岩体内缺陷(裂隙)的扩展与贯通机理,基于三维离散元软件(PFC3D)和改进的平行黏结模型(IPBM),模拟了双轴压缩试验中含双预制裂纹类岩石材料的裂纹扩展过程。通过逼近实验试件抗压强度、抗拉强度和弹性模量的宏观力学参数和裂纹扩展模式,调整数值模型微观参数。针对离散元模拟中的关键预制裂隙参数与围压对裂纹萌生、扩展及贯通过程的影响进行详尽的分析,结果表明:初始裂纹通常为拉伸裂纹,而次生裂纹通常为剪切裂纹,裂隙倾角主要影响初始裂纹位置;围压抑制初始裂纹,但促进次生裂纹发展;预制裂隙间的贯通裂纹与裂隙的参数和围压密切相关;围压σc>0 MPa时,观察到两种新的剪切贯通类型(New1和New2);数值试样中微裂纹的数量主要受围压影响,与裂隙参数无明显关联;试样的裂纹起始应力、峰值应力与围压和裂隙倾角相关,与岩桥长度和岩桥倾角无关;裂纹的扩展与试样内应力分布密切相关,裂纹最先在裂隙周围的应力集中区产生。结果为后续岩石与类岩石材料的离散元模型参数校准,以及基于离散元的裂纹扩展机理研究提供了可靠参考。 展开更多
关键词 类岩石材料 裂纹扩展 三维离散元 数值模拟 双轴压缩
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厚硬顶板刀把形采空区下综放工作面冲击地压机制研究 被引量:1
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作者 钟涛平 李振雷 +4 位作者 杨伟 赵志鹏 宋大钊 李红平 周超 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第6期29-39,共11页
不规则的开采空间结构可增大煤矿冲击地压危险,研究多煤层复杂开采空间结构下工作面冲击机制对煤炭资源安全采出具有重要意义。综合采用理论分析、数值模拟、现场监测等方法,研究了某矿井W1123综放工作面的动静载分布特征,分析了冲击显... 不规则的开采空间结构可增大煤矿冲击地压危险,研究多煤层复杂开采空间结构下工作面冲击机制对煤炭资源安全采出具有重要意义。综合采用理论分析、数值模拟、现场监测等方法,研究了某矿井W1123综放工作面的动静载分布特征,分析了冲击显现机制,提出了针对性的防冲措施并进行现场应用。结果表明,上覆刀把形采空区和厚硬顶板综合作用下W1123工作面动静载分布具有区域性特征,当工作面仅受到刀把形采空区的“刀柄”作用或同时受“刀柄”和“刀身”作用时,工作面中下部和区段煤柱静载集中、动载扰动剧烈,工作面回风巷围岩也存在动静载集中,且距离刀把形采空边界越近则围岩动静载越高;仅受“刀身”作用时,工作面回风巷围岩静载集中受动载扰动。工作面静载集中区和动载扰动区重合,动静载叠加造成冲击显现。依据刀把形采空区结构特征,W1123工作面回采期间冲击类型依次为强动载型、高静载强动载型、高静载型。数值模拟和现场监测揭示的冲击危险区与理论分析结果一致。针对W1123工作面静动载分布特征,优化设计了冲击地压防治措施,增大了厚硬顶板处理高度和破碎程度、增加了工作面运输巷煤体爆破和煤柱切顶以降低顶板和煤体应力和能量集中;优化措施实施后,工作面微震事件日均能量总体下降54%,大能量事件大幅减少,冲击地压危险显著降低。该研究结果可为相似条件矿井的冲击地压防治提供借鉴。 展开更多
关键词 冲击地压 刀把形采空区 综放工作面 静载分布 动载扰动 厚硬顶板
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SiO_(2)-MgO-MgCl_(2)的微观结构与性能研究
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作者 景杰 李虹波 +1 位作者 郑鑫 赵锴 《广州化工》 CAS 2024年第8期67-70,共4页
以氯氧镁(MOC)为粘结剂,球形石英砂为骨料,在摩尔比MgO∶MgCl_(2)·6H_(2)O∶H_(2)O为7∶1∶18时,研究湿度、粘结剂含量对微观结构和性能的影响。结果表明:MOC的粘结强度贡献主要来源于5相水化物,其在5%RH中相对稳定,其中粘结剂含量... 以氯氧镁(MOC)为粘结剂,球形石英砂为骨料,在摩尔比MgO∶MgCl_(2)·6H_(2)O∶H_(2)O为7∶1∶18时,研究湿度、粘结剂含量对微观结构和性能的影响。结果表明:MOC的粘结强度贡献主要来源于5相水化物,其在5%RH中相对稳定,其中粘结剂含量为20%~30%的样品7天强度均达到了20 MPa以上。适当提高湿度有利于5相的生成,但同时生成氢氧化镁,造成样品强度和刚度损失。综合来看,SiO_(2)-MgO-MgCl_(2)材料体系拥有较优秀的早期强度和类似于天然岩石的破坏特征,可作为一种潜在的类岩石材料。 展开更多
关键词 类岩石材料 氯氧镁水泥 微观结构 抗压强度 刚度
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基于核磁共振技术的类岩石细观特征及对渗透率影响研究
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作者 刘志雄 赵天成 +1 位作者 孙鹏 庞政 《内蒙古科技大学学报》 CAS 2024年第3期218-221,共4页
为探究不同载荷下岩石细观结构变化及对渗透率的影响,采用核磁共振设备测试了8个不同载荷下混凝土试样的各孔径孔隙分布情况。对不同载荷下孔径分布图进行分析,获得了不同加载条件下试样内部细观特征变化规律。通过核磁共振中所得细观... 为探究不同载荷下岩石细观结构变化及对渗透率的影响,采用核磁共振设备测试了8个不同载荷下混凝土试样的各孔径孔隙分布情况。对不同载荷下孔径分布图进行分析,获得了不同加载条件下试样内部细观特征变化规律。通过核磁共振中所得细观定量表征数据,研究细观特征对试样渗透率的影响情况,建立了渗透率与各孔径孔隙占比的定量计算模型。结果表明:随着载荷的增加,试样内部各孔径孔隙数量逐渐增加,小孔增幅越来越小,大孔增幅越来越大。微小孔占比与渗透率呈负相关关系,中大孔占比与渗透率表现出了较好的正相关关系。 展开更多
关键词 类岩石试样 核磁共振技术 不同载荷 细观结构 渗透率
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沿海岩质边坡中风化花岗岩相似材料配比试验研究
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作者 吴禄源 张晨曦 +2 位作者 张建伟 边汉亮 马宇豪 《中国科技论文》 CAS 2024年第4期491-497,共7页
为研究东南沿海岩质边坡在地震作用下的岩质边坡动力响应,首先对中风化花岗岩相似材料进行配比模拟试验。试验选取铁粉、石英砂为骨料,水泥、黏土、水为调节材料,速凝剂为粘结剂的相似材料配比方案,设计了五因素四水平的正交表,并进行... 为研究东南沿海岩质边坡在地震作用下的岩质边坡动力响应,首先对中风化花岗岩相似材料进行配比模拟试验。试验选取铁粉、石英砂为骨料,水泥、黏土、水为调节材料,速凝剂为粘结剂的相似材料配比方案,设计了五因素四水平的正交表,并进行岩石压缩试验。结果表明:黏土质量主要影响相似材料的弹性模量,相似材料的弹性模量随黏土质量的增加而增大;铁粉质量对相似材料的弹性模量和黏聚力均具有重大贡献;水泥质量对相似材料的影响较为稳定;最适宜的振动台试验配比(质量比)为铁粉∶石英砂∶水泥∶黏土∶速凝剂∶水=405∶800∶130∶16∶2.1∶140。该试验以材料为因素变量进行正交设计,所得结论可为其他振动台试验材料模拟提供参考。 展开更多
关键词 大型振动台试验 正交设计 中风化花岗岩相似材料 岩石压缩试验
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