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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 ***,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is *** triaxial static compression and intermittent disturbance tests are carried out on *** 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 *** increases in microseismic parameters during rock loading can be precursors for intermittent rock *** 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 *** sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are *** 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

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Ordered mesoporous materials for water pollution treatment: Adsorption and catalysis

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Green Energy & Environment 2024年第8期9卷 1239-1256页

作者： Peng Zhang Mingming He Wei Teng Fukuan Li Xinyuan Qiu Kexun Li Hao Wang College of Environmental Science and engineering MOE Key Laboratory of Pollution Processes and Environmental CriteriaTianjin Key Laboratory of Environmental Remediation and Pollution TreatmentTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai University Department of Chemistry and State Key Laboratory Marine Pollution Hong Kong institute for Advanced Study City University of Hong Kong State Key Laboratory for Pollution Treatment College of Environmental Science and EngineeringShanghai Institute of Pollution Treatment and Ecological SecurityTongji University State Key Laboratory of Simulation and Regulation of water Cycles in River Basins China Institute of Water Resources and Hydropower Research

To meet the growing emission of water contaminants,the development of new materials that enhance the efficiency of the water treatment system is *** mesoporous materials provide opportunities in environmental processing applications due to their exceptionally high surface areas,large pore sizes,and enough pore *** properties might enhance the performance of materials concerning adsorption/catalysis capability,durability,and *** this review,we enumerate the ordered mesoporous materials as adsorbents/catalysts and their modifications in water pollution treatment from the past decade,including heavy metals (Hg2+,Pb2+,Cd2+,Cr6+,etc.),toxic anions （nitrate,phosphate,fluoride,etc.）,and organic contaminants （organic dyes,antibiotics,etc.）.These contributions demonstrate a deep understanding of the synergistic effect between the incorporated framework and homogeneous active ***,the challenges and perspectives of the future developments of ordered mesoporous materials in wastewater treatment are *** work provides a theoretical basis and complete summary for the application of ordered mesoporous materials in the removal of contaminants from aqueous solutions.

关键词： water pollution treatment Ordered mesoporous materials Toxic contaminants Adsorption Catalysis

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Contract Mechanism of water Environment Regulation for Small and Medium Sized Enterprises Based on Optimal Control Theory

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Journal of water Resource and Protection 2024年第7期16卷 538-556页

作者： Shuang Zhao Hongbin Gu Lianfang Xue Dongsheng Wang Bin Huang China institute of water resources and hydropower Research Beijing China China Renewable engineering institute Beijing China School of Environmental Science and engineering Tianjin University Tianjin China

The small and scattered enterprise pattern in the county economy has formed numerous sporadic pollution sources, hindering the centralized treatment of the water environment, increasing the cost and difficulty of treatment. How enterprises can make reasonable decisions on their water environment behavior based on the external environment and their own factors is of great significance for scientifically and effectively designing water environment regulation mechanisms. Based on optimal control theory, this study investigates the design of contractual mechanisms for water environmental regulation for small and medium-sized enterprises. The enterprise is regarded as an independent economic entity that can adopt optimal control strategies to maximize its own interests. Based on the participation of multiple subjects including the government, enterprises, and the public, an optimal control strategy model for enterprises under contractual water environmental regulation is constructed using optimal control theory, and a method for calculating the amount of unit pollutant penalties is derived. The water pollutant treatment cost data of a paper company is selected to conduct empirical numerical analysis on the model. The results show that the increase in the probability of government regulation and public participation, as well as the decrease in local government protection for enterprises, can achieve the same regulatory effect while reducing the number of administrative penalties per unit. Finally, the implementation process of contractual water environmental regulation for small and medium-sized enterprises is designed.

关键词： Optimal Control Theory Small and Medium-Sized Enterprises water Environment Regulation Contract Mechanism

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Influence of cutterhead opening ratio on soil arching effect and face stability during tunnelling through non-uniform soils

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Underground Space 2024年第4期17卷 45-59页

作者： Xue-Jian Chen Pei-Pei Fang Qiu-Nan Chen Jun Hu Kai Yao Yong Liu State Key Laboratory of water resources engineering and Management Wuhan UniversityWuhan 430072China Hubei Technology Innovation Center for Smart hydropower Wuhan 430000China College of Civil engineering Anhui Jianzhu UniversityHefei 230601China School of Civil engineering Hunan University of Science and TechnologyXiangtan 411201China School of Civil and Architectural engineering Hainan UniversityHaikou 570228China School of Qilu Transportation Shandong UniversityJinan 250002China

Tunnelling has increasingly become an essential tool in the exploration of underground space.A typical construction problem is the face instability during tunnelling,posing a great threat to associated *** face instability often occurs with the soil arching *** study investigates the combined effect of cutterhead opening ratio and soil non-uniformity on soil arching effect and face stability,via conducting random finite-element analysis coupled with Monte–Carlo *** results underscore that the face stability is strongly associated with the evolution of stress *** obtained stability factors in the uniform soils can serve as a reference for the design of support pressure in practical tunnelling *** addition,non-uniform soils exhibit a lower stability factor than uniform soils,which implies that the latter likely yields an underestimated probability of face *** tunnel face is found to have a probability of failure more than 50%if the spatial non-uniformity of soil is *** the end,a practical framework is established to determine factor of safety(FOS)corresponding to different levels of probability of face failure considering various opening ratios in non-uniform *** required FOS is 1.70 to limit the probability of face instability no more than 0.1%.Our findings can facilitate the prediction of probability of instability in the conventionally deterministic design of face pressure.

关键词： Tunnel Face stability Soil arching effect Cutterhead opening ratio Non-uniform soil Random field

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Cavitation research with computational fluid dynamics:From Euler-Euler to Euler-Lagrange approach

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Journal of Hydrodynamics 2024年第1期36卷 1-23页

作者： Bin Ji Zi-yang Wang Huai-yu Cheng Rickard E.Bensow State Key Laboratory of water resources engineering and Management Wuhan UniversityWuhan430072China Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

Unsteady cavitating flow often contains vapor structures with a wide range of different length scales,from micro-bubbles to large cavities,which issues a big challenge to precisely investigate its evolution mechanism by computational fluid dynamics(CFD)*** present work reviews the development of simulation methods for cavitation,especially the emerging Euler-Lagrange ***,the progress of the numerical investigation of hot and vital issues is discussed,including cavitation inception,cloud cavitation inner structure and its formation mechanism,cavitation erosion,and cavitation *** is indicated that the Euler-Lagrange method can determine cavitation inception point *** cloud cavitation,the Euler-Lagrange method can reveal the source of microbubbles and their distribution law inside the shedding *** method also has advantages and great potential in assessing cloud cavitation-induced erosion and *** the ever-growing demands of cavitation simulation accuracy in basic research and engineering applications,how to improve the Euler-Lagrange method’s stability and applicability is still an open *** further promote the application of this advanced CFD simulation technology in cavitation research,some key issues are to be solved and feasible suggestions are put forward for further work.

关键词： numerical simulation Euler-Euler method Euler-Lagrange method bubble dynamicsgy,Gothenburg,Sweden

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Agricultural drought vulnerability in the middle reaches of Yangtze River Basin under environmental change

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Journal of Earth Science 2024年

作者： Peng Yang Fei Xu Jun Xia Jiang Li Libo Zhou Cai Fu State Key Laboratory of Hydroscience and engineering， Tsinghua University School of Geography and Information engineering， China University of Geosciences Information Center of Department of Natural resources of Hubei Province School of water resources and hydropower engineering， Wuhan University Wuhan C-Geo Clouds Science and Tech Co.， Ltd

Climate change and economic development impact the population expansion and water shortage in the middle reaches of the Yangtze River Basin (MYRB)， leading directly to drought aggravation-expansion and impacting agricultural production in the MYRB. Therefore， this study quantitatively evaluated agricultural drought vulnerability in the MYRB based on the variable fuzzy evaluation model (VFEM). The main conclusions are as follows: (1) The arable land in the MYRB gradually decreased between 2005 and 2020， whereas the forest cover decreased and then increased; (2) precipitation and evapotranspiration were the key factors affecting the agricultural drought vulnerability (e.g.， weights of 0.24 and 0.21)， whereas arable land density and gross domestic product (GDP) per capita played less significant roles; and (3) the agricultural drought vulnerability in the MYRB during 2005–2020 was mainly at level 3 and below， with higher drought vulnerability in the western and northern regions， which had a higher drought risk potential.

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Optimization of the co-closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui Liu Yun-fa Lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi Fan State Key Laboratory of water resources engineering and Management Wuhan UniversityWuhan430072China Dongfang Electric Machinery Co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of *** this study,we proposed a procedure to optimize the co-closing law of GVs and RBs by using computational fluid dynamics(CFD),combined with the design of experiment(DOE)method,approximation model,and genetic optimization *** sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was *** results show that GVs dominate the transient characteristics by controlling the change of *** GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’second-stage closing speed is conducive to controlling the maximum reverse axial *** directly affect the runner *** RBs’closing speed can further reduce the rotational speed and the maximum reverse axial *** safety margin of each control parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization computational fluid dynamics(CFD)

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Advancing flood susceptibility modeling using stacking ensemble machine learning: A multi-model approach

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Journal of Geographical Sciences 2024年第8期34卷 1513-1536页

作者： YANG Huilin YAO Rui DONG Linyao SUN Peng ZHANG Qiang WEI Yongqiang SUN Shao AGHAKOUCHAK Amir School of Geography and Tourism Anhui Normal UniversityWuhu 241002AnhuiChina Changjiang River Scientific Research institute Wuhan 430015China Advanced Interdisciplinary institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087GuangdongChina Hunan institute of water resources and hydropower Research Changsha 410007China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Civil and Environmental engineering University of California IrvineIrvineCA 92697USA

Flood susceptibility modeling is crucial for rapid flood forecasting, disaster reduction strategies, evacuation planning, and decision-making. Machine learning(ML) models have proven to be effective tools for assessing flood susceptibility. However, most previous studies have focused on individual models or comparative performance, underscoring the unique strengths and weaknesses of each model. In this study, we propose a stacking ensemble learning algorithm that harnesses the strengths of a diverse range of machine learning models. The findings reveal the following:(1) The stacking ensemble learning, using RF-XGBCB-LR model, significantly enhances flood susceptibility simulation.(2) In addition to rainfall,key flood drivers in the study area include NDVI, and impervious surfaces. Over 40% of the study area, primarily in the northeast and southeast, exhibits high flood susceptibility, with higher risks for populations compared to cropland.(3) In the northeast of the study area,heavy precipitation, low terrain, and NDVI values are key indicators contributing to high flood susceptibility, while long-duration precipitation, mountainous topography, and upper reach vegetation are the main drivers in the southeast. This study underscores the effectiveness of ML, particularly ensemble learning, in flood modeling. It identifies vulnerable areas and contributes to improved flood risk management.

关键词： flood susceptibility assessment machine learning stacking ensemble learning flood drivers XiangjiangRiverBasin

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investigation of anisotropic strength criteria for layered rock mass

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Journal of Rock Mechanics and Geotechnical engineering 2024年第4期16卷 1289-1304页

作者： Shuling Huang Jinxin Zhang Xiuli Ding Chuanqing Zhang Gang Han Guoqi Yu Lulu Qu Key Laboratory of Geotechnical Mechanics and engineering of the Ministry of water resources Changjiang River Scientific Research InstituteWuhan430071China State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430000China University of Chinese Academy of Sciences Beijing100049China

Layered rock mass is a type of engineering rock mass with sound mechanical anisotropy,which is generally unfavorable to the stability of underground *** investigate the strength anisotropy of layered rock,the Mohr-Coulomb and Hoek-Brown criteria are introduced to establish the two transverse isotropic strength criteria based on Jaeger's single weak plane theory and maximum axial strain theory,and parameter determination ***,the sensitivity of strength parameters(K 1,K 2,and K 3)that are used to characterize the anisotropy strength of non-sliding failure involved in the strength criteria and confining pressure are *** results demonstrate that strength parameters K 1 and K 2 affect the strength of layered rock samples at all bedding angles except for the bedding angle of 90°and the angle range that can cause the shear sliding failure along the bedding *** strength of samples at any bedding angle decreases with increasing K 1,whereas the opposite is for K *** for bedding angles of 0°and 90°and the bedding angle range that can cause the shear sliding along the bedding plane,K 3 has an impact on the strength of rock samples with other bedding angles that the specimens'strength increases with increase of K *** addition,the strength of the rock sample increases as confining pressure ***,the uniaxial and triaxial tests of chlorite schist samples were carried out to verify and evaluate the strength criteria proposed in the *** shows that the predicted strength is in good agreement with the experimental *** test the applicability of the strength criterion,the strength data of several types of rock in the literature are ***,a comparison is made between the fitting effects of the two strength criteria and other available criteria for layered rocks.

关键词： Layered rock Strength anisotropy Strength criterion Experimental verification

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水电梯级开发真的破坏下游河段营养盐情势吗?

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Science Bulletin 2024年第5期69卷 661-670页

作者：陈求稳陈宇琛林育青张建云倪晋仁夏军肖琳冯韬马宏海 State Key Laboratory of Hydrology-water resources&Hydraulic engineering Nanjing Hydraulic Research InstituteNanjing 210029China Center for Eco-Environment Research Nanjing Hydraulic Research InstituteNanjing 210029China Yangtze institute for Conservation and Green Development Nanjing 210024China School of the Environment Nanjing UniversityNanjing 210008China The Key Laboratory of water and Sediment Sciences Ministry of EducationPeking UniversityBeijing 100091China State Key Laboratory of water resources and hydropower engineering Sciences Wuhan UniversityWuhan 430072China

River damming is believed to largely intercept nutrients,particularly retain more phosphorus(P)than nitrogen(N),and thus harm primary productivity,fishery catches,and food security downstream,which seriously constrain global hydropower development and poverty relief in undeveloped regions and can drive geo-political disputes between nations along trans-boundary *** this study,we investigated whether reservoirs can instead improve nutrient regimes *** measured different species of N and P as well as microbial functions in water and sediment of cascade reservoirs in the upper Mekong River over 5 years and modelled the influx and outflux of N and P species in each *** partially retaining total N and total P,reservoirs increased the downstream flux of ammonium and soluble reactive phosphorus(SRP).The increase in ammonium and SRP between outflux and influx showed positive linear relationships with the hydraulic residence time of the cascade reservoirs;and the ratio of SRP to dissolved inorganic nitrogen increased along the reservoir *** lentic environment of reservoirs stimulated algae-mediated conversion of nitrate into ammonium in surface water;the hypoxic condition and the priming effect of algae-induced organic matter enhanced release of ammonium from sediment;the synergy of microbial phosphorylation,reductive condition and sediment geochemical properties increased release of *** study is the first to provide solid evidence that hydropower reservoirs improve downstream nutrient bioavailability and N-P balance through a process of retention-transformation-transport,which may benefit primary *** findings could advance our understanding of the eco-environmental impacts of river damming.

关键词： River damming Biogeochemical cycle Nitrogen Phosphorus Ecological impacts

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