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Instability mechanism of mining roadway passing through fault at different angles in kilometre-deep mine and control measures of roof cutting and NPR cables

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Journal of Mountain Science 2024年第1期21卷 236-251页

作者： SUN Xiaoming WANG Jian ZHAO Wenchao MING Jiang ZHANG Yong LI Zhihu MIAO Chengyu GUO Zhibiao HE Manchao state key laboratory for geomechanics and deep underground engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil engineering China University of Mining and Technology(Beijing)Beijing 100083China

The angle α between the fault strike and the axial direction of the roadway produces different damage characteristics. In this paper, the research methodology includes theoretical analyses, numerical simulations and field experiments in the context of the Daqiang coal mine located in Shenyang, China. The stability control countermeasure of "pre-splitting cutting roof + NPR anchor cable"(PSCR-NPR) is simultaneously proposed. According to the different deformation characteristics of the roadway, the faults are innovatively classified into three types, with α of type I being 0°-30°, α of type II being 30°-60°, and α of type III being 60°-90°. The full-cycle stress evolution paths during mining roadway traverses across different types of faults are investigated by numerical simulation. Different pinch angles α lead to high stress concentration areas at different locations in the surrounding rock. The non-uniform stress field formed in the shallow surrounding rock is an important reason for the instability of the roadway. The pre-cracked cut top shifted the high stress region to the deep rock mass and formed a low stress region in the shallow rock mass. The high prestressing NPR anchor cable transforms the non-uniform stress field of the shallow surrounding rock into a uniform stress field. PSCR-NPR is applied in the fault-through roadway of Daqiang mine. The low stress area of the surrounding rock was enlarged by 3-7 times, and the cumulative convergence was reduced by 45%-50%. It provides a reference for the stability control of the deep fault-through mining roadway.

关键词： Kilometre-deep mine Fault Mining roadway Failure mechanism Pre-splitting cutting roof High pre-stress NPR anchor cable

Experimental study on the effect of water absorption level on rockburst occurrence of sandstone

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Journal of Rock Mechanics and Geotechnical engineering 2024年第1期16卷 136-152页

作者： Dongqiao Liu Jie Sun Pengfei He Manchao He Binghao Cao Yuanyuan Yang state key laboratory for geomechanics and deep underground engineering China University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil engineering China University of Mining and Technology(Beijing)Beijing100083China Institute for deep underground Science and engineering China University of Mining and Technology(Beijing)Beijing100083China

To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single face.High-speed photography and acoustic emission(AE)system are used to monitor the rockburst process.The effect of water on sandstone rockburst and the prevention mechanism of water on sandstone rockburst are analyzed from the perspective of energy and failure mode.The results show that the higher the ab-sorption degree,the lower the intensity of the rockburst after absorbing water on single side of sand-stone.This is reflected in the fact that with the increase in the water absorption level,the ejection velocity of rockburst fragments is smaller,the depth of the rockburst pit is shallower,and the AE energy is smaller.Under the water absorption level of 100%,the magnitude of rockburst intensity changes from medium to slight.The prevention mechanism of water on sandstone rockburst is that water reduces the capacity of sandstone to store strain energy and accelerates the expansion of shear cracks,which is not conducive to the occurrence of plate cracking before rockburst,and destroys the conditions for rockburst incubation.

关键词： Rockburst Water Prevention effect Crack evolution

RB-DEM Modeling and Simulation of Non-Persisting Rough Open Joints Based on the IFS-Enhanced Method

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Computer Modeling in engineering & Sciences 2024年第4期139卷 337-359页

作者： Hangtian Song Xudong Chen Chun Zhu Qian Yin Wei Wang Qingxiang Meng key laboratory of Ministry of Education for geomechanics and Embankment engineering Hohai UniversityNanjing210098China Research Institute of Geotechnical engineering Hohai UniversityNanjing210098China School of Earth Sciences and engineering Hohai UniversityNanjing210098China state key laboratory for geomechanics and deep underground engineering China University of Mining and TechnologyXuzhou221116China

When the geological environment of rock masses is disturbed,numerous non-persisting open joints can appear within it.It is crucial to investigate the effect of open joints on the mechanical properties of rock mass.However,it has been challenging to generate realistic open joints in traditional experimental tests and numerical simulations.This paper presents a novel solution to solve the problem.By utilizing the stochastic distribution of joints and an enhanced-fractal interpolation system(IFS)method,rough curves with any orientation can be generated.The Douglas-Peucker algorithm is then applied to simplify these curves by removing unnecessary points while preserving their fundamental shape.Subsequently,open joints are created by connecting points that move to both sides of rough curves based on the aperture distribution.Mesh modeling is performed to construct the final mesh model.Finally,the RB-DEM method is applied to transform the mesh model into a discrete element model containing geometric information about these open joints.Furthermore,this study explores the impacts of rough open joint orientation,aperture,and number on rock fracture mechanics.This method provides a realistic and effective approach for modeling and simulating these non-persisting open joints.

关键词： Non-persisting rough open joints stochastic distribution of joints enhanced-IFS method RB-DEM

Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths

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International Journal of Mining Science and Technology 2024年第1期34卷 117-136页

作者： Zhi Zheng Hongyu Xu Kai Zhang Guangliang Feng Qiang Zhang Yufei Zhao state key laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China state key laboratory of geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China state key laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100080China state key laboratory for geomechanics and deep underground engineering China University of Mining and TechnologyXuzhou 221116China

Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing disasters.Therefore,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is proposed.True triaxial static compression and intermittent disturbance tests are carried out on monzogabbro.The effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture mechanism.Rapid increases in microseismic parameters during rock loading can be precursors for intermittent rock disturbance.Based on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental results.The sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are predicted.This study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.

关键词： True triaxial static and disturbance test Mechanical properties Failure mechanism and precursor Intermittent disturbance effect Fractional mechanical model

A review of rock macro-indentation:Theories,experiments,simulations,and applications

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2351-2374页

作者： Weiqiang Xie Xiaoli Liu Xiaoping Zhang Xinmei Yang Xiaoxiong Zhou state key laboratory of Hydroscience and engineering Tsinghua UniversityBeijing100084China Yunlong Lake laboratory of deep underground Science and engineering Xuzhou221116China state key laboratory of Water Resources and Hydropower engineering Science Wuhan UniversityWuhan430072China

Rock macro-indentation plays a fundamental role in mechanical rock breaking for various rock engineering application,such as drilling,tunneling,cutting,and sawing.Over the past decades,extensive research has been conducted to understand the indentation mechanisms and responses through various approaches.This review aims to provide an overview of the current status and recent advancements in theories,experiments,numerical simulations,and applications of macro-indentation in rock engineering.It starts with elaborating on the mechanisms of macro-indentation,followed by a discussion of the merits and limitations of commonly used models.Influence factors and their effects on indentation test results are then summarized.Various numerical simulation methods for rock macro-indentation are highlighted,along with their advantages and disadvantages.Subsequently,the applications of indentation tests and indentation indices in characterizing rock properties are explored.It reveals that compression-tension,compression-shear,and composite models are widely employed in rock macroindentation.While the compression-tension model is straightforward to use,it may overlook the anisotropic properties of rocks.On the other hand,the composite model provides a more comprehensive description of rock indentation but requires complex calculations.Additionally,factors,such as indentation rate,indenter geometry,rock type,specimen size,and confining pressure,can significantly influence the indentation results.Simulation methods for macro-indentation encompass continuous medium,discontinuous medium,and continuous-discontinuous medium methods,with selection based on their differences in principle.Furthermore,rock macro-indentation can be practically applied to mining engineering,tunneling engineering,and petroleum drilling engineering.Indentation indices serve as valuable tools for characterizing rock strength,brittleness,and drillability.This review sheds light on the development of rock macro-indentation and its extensive application in enginee

关键词： Rock macro-indentation Indentation test Indentation indices Mechanism Rock breaking

Velocity analysis of supersonic jet flow in double-cone ignition scheme

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Chinese Physics B 2024年第6期33卷 460-465页

作者：朱仲源张成龙李英骏 School of Science China University of Mining and TechnologyBeijing 100083China state key laboratory for geomechanics and deep underground engineering China University of Mining and TechnologyBeijing 100083China Double-cone ignition(DCI)joint team State Key Laboratory for Geomechanics and Deep Underground EngineeringChina University of Mining and TechnologyBeijing 100083China

In the double-cone ignition schemes(DCIS), the deuterium–tritium target shell is ablated and compressed by a highpower nanosecond laser in Au-cones to generate plasmas. Under the actions of spherically symmetric compression and acceleration along the Au cone, they will be ejected out of the cone mouth and collide with each other. The plasmas experience conversion from kinetic energy to internal energy at the vertex of the geometric center of two Au cones that are symmetric to each other, because of which high-density fusion plasmas are preheated. This key physical process has undergone experimental verification on the Shenguang-II upgraded facility in China. Apparently, the improvement and optimization of the velocity of plasmas in hypersonic jet flow at the cone mouth are crucial for the success of the DCIS. In the DCIR7 experiment of the Shenguang-II upgraded facility, a velocity yield of approximately 130–260 km/s was achieved for the plasmas at the cone mouth, with a result of nearly 300 km/s based on numerical simulation. In this paper, theoretical analysis is performed as regards the process, in which target shells are ablated and compressed by laser to generate highvelocity plasmas ejected through jet flow. Based on this analysis, the formula for the velocity of plasmas in supersonic jet flow at the cone mouth is proposed. This study also provides measures that are more effective for improving the kinetic energy of plasmas and optimizing energy conversion efficiency, which can serve as theoretical references for the adjustment and optimization of processes in subsequent experiments.

关键词： double-cone ignition(DCI) plasma hydrodynamics laser fusion

Real-Time Observation of Instantaneous ac Stark Shift of a Vacuum Using a Zeptosecond Laser Pulse

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Chinese Physics Letters 2024年第1期41卷 11-15页

作者：苏丹丹江淼 key laboratory for Laser Plasmas(Ministry of Education)and School of Physics and Astronomy Collaborative Innovation Center for IFSA(CICIFSA)Shanghai Jiao Tong UniversityShanghai 200240China School of Science China University of Mining and TechnologyBeijing 100083China state key laboratory for geomechanics and deep underground engineering China University of Mining and TechnologyBeijing 100083China

Based on the numerical solution of the time-dependent Dirac equation,we propose a method to observe in real time the ac Stark shift of a vacuum driven by an ultra-intense laser field.By overlapping the ultra-intense pump pulse with another zeptosecond probe pulse whose photon energy is smaller than 2mc^(2),electron–positron pair creation can be controlled by tuning the time delay between the pump and probe pulses.Since the pair creation rate depends sensitively on the instantaneous vacuum potential,one can reconstruct the ac Stark shift of the vacuum potential according to the time-delay-dependent pair creation rate.

关键词： pump tuning vacuum

Wetting-drying effect on the strength and microstructure of cementphosphogypsum stabilized soils

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 1049-1058页

作者： Lingling Zeng Xia Bian Jiaxing Weng Tao Zhang College of Civil engineering Zhejiang University of TechnologyHanzhou310014China key laboratory of Ministry of Education for geomechanics and Embankment engineering Hohai UniversityNanjing210098China state key laboratory for geomechanics and deep underground engineering China University of Mining and TechnologyXuzhou221116China Jiangsu Water Source Company Ltd.of the Eastern Route of the South-to-North Water Diversion Project Nanjing210000China Power China Zhongnan engineering Corporation Limited Changsha410027China

Phosphogypsum has often been used as an effective and environmentally friendly binder for partial replacement of cement,improving the engineering properties of slurries with high water content.However,the influence of phosphogypsum on the physicomechnical properties of stabilized soil subjected to wettingedrying cycles is not well understood to date.In this study,the effect of phosphogypsum on the durability of stabilized soil was studied by conducting a series of laboratory experiments,illustrating the changes in mass loss,pH value and unconfined compressive strength(qu)with wettingdrying cycles.The test results showed that the presence of phosphogypsum significantly restrained the mass loss in the early stage(lower than the 4th cycle),which in turn led to a higher qu of stabilized soil than that without phosphogypsum.After the 4th cycle,a sudden increase in mass loss was observed for stabilized soil with phosphogypsum,resulting in a significant drop in qu to a value lower than those without phosphogypsum at the 6th cycle.In addition,the qu of stabilized soils correlated well with the measured soil pH irrespective of phosphogypsum content for all wettingedrying tests.According to the microstructure observation via scanning electron microscope(SEM)and X-ray diffraction(XRD)tests,the mechanisms relating the sudden loss of qu for the stabilized soils with phosphogypsum after the 4th wetting-drying cycle are summarized as follows:(i)the disappearance of ettringite weakening the cementation bonding effect,(ii)the generation of a larger extent of microcrack,and(iii)a lower pH value,in comparison with the stabilized soil without phosphogypsum.

关键词： Wetting-drying Phosphogypsum Microstructure Durability

基于大变形升阻锚索深埋巷道围岩稳定性控制研究

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Journal of Central South University 2024年第2期31卷 558-575页

作者：孟波尹乾靖洪文刘盛东贾邦国 School of Mechanics and Civil engineering China University of Mining and TechnologyXuzhou 221116China state key laboratory for geomechanics&deep underground engineering China University of Mining and TechnologyXuzhou 221116China Yunlong Lake laboratory of deep underground Science and engineering Xuzhou 221116China

研发了一种新型大变形升阻锚索支护结构,通过串联6个壁厚5 mm含环形V槽的直管型钢结构实现锚索吸能让压,吸能率为44.55 J/g。拉拔试验结果表明新型锚索极限变形量(221.58 mm)与普通传统锚索相比增加了4.87倍,具有大变形、增阻及高吸能... 详细信息

研发了一种新型大变形升阻锚索支护结构,通过串联6个壁厚5 mm含环形V槽的直管型钢结构实现锚索吸能让压,吸能率为44.55 J/g。拉拔试验结果表明新型锚索极限变形量(221.58 mm)与普通传统锚索相比增加了4.87倍,具有大变形、增阻及高吸能等优良性能。通过离散元UDEC程序的二次开发,模拟了新型大变形增阻锚索支护阻力−变形曲线的双弹性阶段。采用新型锚索对深埋巷道围岩支护效果数值模拟结果表明,与无支护及传统锚索支护相比,顶板下沉量分别减小了88.33%与74.64%,稳定状态下最大主应力峰值分别减小了23.15%与18.34%,塑性区厚度分别减小了37.50%与62.50%。最后将新型大变形增阻锚索成功应用于真实巷道,两帮最大收敛变形量约为300 mm,实现了较好的支护效果。

关键词：大变形增阻吸能结构锚索稳定控制工程应用