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Seasonal freeze-thaw processes impact microbial communities of soil aggregates associated with soil pores on the Qinghai–Tibet Plateau

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Ecological Processes 2024年第2期 279-292页

作者： Rui-Zhe Wang Xia Hu state Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical Science Beijing Normal University School of Natural Resources Faculty of Geographical Science Beijing Normal University

Background Seasonal freeze-thaw(FT) processes alter soil formation and cause changes in soil microbial communi-ties, which regulate the decomposition of organic matter in alpine ecosystems. soil aggregates are basic structural units and play a critical role in microbial habitation. However, the impact of seasonal FT processes on the distribution of microbial communities associated with soil pores in different aggregate fractions under climate change has been overlooked. In this study, we sampled soil aggregates from two typical alpine ecosystems(alpine meadow and alpine shrubland) during the seasonal FT processes(UFP: unstable freezing period, SFP: stable frozen period, UTP: unstable thawing period and STP: stable thawed period). The phospholipid fatty acid(PLFA) method was used to determine the biomass of living microbes in different aggregate *** The microbial biomass of 0.25–2 mm and 0.053–0.25 mm aggregates did not change significantly dur-ing the seasonal FT process while the microbial biomass of > 2 mm aggregates presented a significant difference between the STP and UTP. Bacterial communities dominated the microbes in aggregates, accounting for over 80% of the total PLFAs. The microbial communities of soil aggregates in the surface layer were more sensitive to the sea-sonal FT process than those in other soil layers. In the thawing period, Gram positive bacteria(GP) was more dominant. In the freezing period, the ratio of Gram-positive to Gram-negative bacterial PLFAs(GP/GN) was low because the enrichment of plant litter facilitated the formation of organic matter. In the freezing process, pores of 30–80 μm(mesopores) favored the habitation of fungal and actinobacterial communities while total PLFAs and bacterial PLFAs were negatively correlated with mesopores in the thawing *** The freezing process caused a greater variability in microbial biomass of different aggregate fractions. The thawing process increased the differences in

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Evaluating the thermal environment of urban land surfaces in Yakutsk,a city located in a region of continuous permafrost

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Advances in Climate Change Research 2024年第1期15卷 113-123页

作者： Xiang-Long LI Ze ZHANG Jin-Xin LU Anatoli BROUCHKov Qing-Kai YAN Qi-Hao YU Sheng-Rong ZHANG Andrey MELNIKov School of Civil Engineering and Transportation Institute of Cold Regions Science and EngineeringPermafrost InstituteNortheast Forestry UniversityHarbin150040China China Railway Qinghai-Tibet Group Company Xining 810000China Department of Geocryology Faculty of GeologyLomonosov Moscow State UniversityMoscow 119234Russian Federation state Key Laboratory of Frozen soil Engineering Northwest Institute of Eco Envi ronment and Re sourcesChinese Academy of SciencesLanzhou 730000China Melnikov Permafrost Institute Siberian BranchRussian Academy of ScienceYakutsk 677010Russian Federation

Rapid urbanization has led to changes in the urban land surface thermal ***,there are still much unknown about the urban land surface thermal conditions in permafrost *** is a unique geological environment,changes in the urban land surface thermal environment may trigger geological disasters caused by permafrost *** study utilized remote sensing data and geographic de-tectors to identify the dynamic changes in land surface temperature(LST)and land use/land cover(LU/LC)in Yakutsk,as well as the potential factors contributing to LST *** 1992 and 2020,the built-up area in Yakutsk increased by 36%,and the annual average LST in Yakutsk has risen by 6.67℃,accompanied by an expansion of high-temperature *** ongoing greening efforts,rapid urbanization poses a threat to these green *** in the normalized difference built-up index(NDBI)and land use transfer(LDT)were identified as the primary drivers of urban LST *** integrating geographic detector technology and artificial neural network models,we optimized the selection of input factors in the prediction model and used it to explore the future changes in LST in *** average LST in Yakutsk is expected to reach 23.4℃ and 25.1℃ in 2030 and 2040,respectively,with a further increase in high-temperature *** study provides a reference for ecological,hydrological,and geological assessments of cities in permafrost regions.

关键词： Remote sensing Land surface temperature Land use/Land cover Permafrost Yakutsk

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Failure behavior and strength model of blocky rock mass with and without rockbolts

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International Journal of Mining science and Technology 2024年第6期34卷 747-762页

作者： Chun Zhu Xiansen Xing Manchao He Zhicheng Tang Feng Xiong Zuyang Ye Chaoshui Xu School of Earth sciences and Engineering Hohai UniversityNanjing 210024China Key Laboratory of Water Management and Water Security for Yellow River Basin Ministry of Water Resources(under construction)Zhengzhou 450003China state Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and TechnologyBeijing 10083China faculty of Engineering China University of GeosciencesWuhan 430074China state Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan 430081China School of Chemical Engineering Faculty of SciencesEngineering and TechnologyThe University of AdelaideAdeliade 5005Australia

To better understand the failure behaviours and strength of bolt-reinforced blocky rocks,large scale extensive laboratory experiments are carried out on blocky rock-like specimens with and without rockbolt *** results show that both shear failure and tensile failure along joint surfaces are observed but the shear failure is a main controlling factor for the peak strength of the rock mass with and without *** rockbolts are necked and shear deformation simultaneously happens in bolt reinforced rock *** the joint dip angle increases,the joint shear failure becomes more *** number of rockbolts has a significant impact on the peak strain and uniaxial compressive strength(UCS),but little influence on the deformation modulus of the rock *** the Winkler beam model to represent the rockbolt behaviours,an analytical model for the prediction of the strength of boltreinforced blocky rocks is *** agreement between the UCS values predicted by proposed model and obtained from experiments suggest an encouraging performance of the proposed *** addition,the performance of the proposed model is further assessed using published results in the literature,indicating the proposed model can be used effectively in the prediction of UCS of bolt-reinforced blocky rocks.

关键词： Blocky rock mass Rockbolt ground support Uniaxial compression test Failure mechanism Uniaxial compressive strength model

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Effects of seepage pressure on the mechanical behaviors and microstructure of sandstone

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2033-2051页

作者： Xuewei Liu Juxiang Chen Bin Liu Sai Wang Quansheng Liu Jin Luo state Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China faculty of Engineering China University of GeosciencesWuhan430074China Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China

Surrounding rocks of underground engineering are subjected to long-term seepage pressure,which can deteriorate the mechanical properties and cause serious *** order to understand the impact of seepage pressure on the mechanical property of sandstone,uniaxial compression tests,P-wave velocity measurements,and nuclear magnetic resonance(NMR)tests were conducted on saturated sandstone samples with varied seepage pressures(i.e.0 MPa,3 MPa,4 MPa,5 MPa,6 MPa,7 MPa).The results demonstrate that the mechanical parameters(uniaxial compressive strength,peak strain,elastic modulus,and brittleness index),total energy,elastic strain energy,as well as elastic strain energy ratio,decrease with increasing seepage pressure,while the dissipation energy and dissipation energy ratio ***,as seepage pressure increases,the micro-pores gradually transform into meso-pores and *** increases the cumulative porosity of sandstone and decreases P-wave *** numerical results indicate that as seepage pressure rises,the number of tensile cracks increases progressively,the angle range of microcracks is basically from 50-120to 80-100,and as a result,the failure mode transforms to the tensile-shear mixed failure ***,the effects of seepage pressure on mechanical properties were *** results show that decrease in the effective stress and cohesion under the action of seepage pressure could lead to deterioration of strength behaviors of sandstone.

关键词： Rock mechanics Mechanical property Seepage pressure Numerical simulation Microcracks

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Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3063-3079页

作者： Qiong Wu Zhiqi Liu Huiming Tang Liangqing Wang Xiaoxue Huo Zhen Cui Shiyu Li Bo Zhang Zhiwei Lin faculty of Engineering China University of GeosciencesWuhan430074China Guangxi Fangchenggang Beitou Environmental Protection Water Co. Ltd.Fangchenggang538021China state Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of *** this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold *** shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear *** results indicate that the shear stress *** displacement curves under each shear cycle and the peak shear strength *** number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with *** peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing *** normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.

关键词： Discontinuities with different joint wall material(DDJM) Discontinuities with identical joint wall material(DIJM) Cyclic shear test Shear strength deterioration Joint surface morphology Shear displacement amplitude Shear rate Normal stress

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Swelling behaviors of heterogeneous red-bed mudstone subjected to different vertical stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1847-1863页

作者： Kang Huang Zhangjun Dai Chengzeng Yan Fei Yu Wei Zhang Shanxiong Chen state Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China university of Chinese Academy of sciences Beijing100049China faculty of Engineering China University of GeosciencesWuhanChina International Joint Research Center for Deep Earth Drilling and Resource Development China University of GeosciencesWuhan430074China

In this study,the axial swelling strain of red-bed mudstone under different vertical stresses are measured by swell-under-load method,and the microstructure of mudstone after hygroscopic swelling is studied by mercury intrusion porosimetry(MIP).The weakening coefficient and Weibull distribution function are introduced into the coupling model of mudstone moisture diffusion-swelling deformation-fracture based on finite-discrete element method(FDEM).The weakening effect of moisture on mudstone's mechanical parameters,as well as the heterogeneity of swelling deformation and stress distribution,is *** microcrack behavior and energy evolution of mudstone during hygroscopic swelling deformation under different vertical stresses are *** results show that the axial swelling strain of mudstone decreases with increase of the vertical *** low vertical stresses,moisture absorption in mudstone leads to formation of cracks caused by hydration-induced *** high vertical stresses,a muddy sealing zone forms on the mudstone surface,preventing further water *** simulation results of mudstone swelling deformation also demonstrate that it involves both swelling of the mudstone matrix and swelling caused by crack ***,crack expansion plays a dominant role in mudstone *** increasing vertical stress,the cracks in mudstone change from tensile cracks to shear cracks,resulting in a significant reduction in the total number of *** the evolution of mudstone kinetic energy shows similarities under different vertical stresses,the evolution of strain energy varies significantly due to the presence of different types of cracks in the *** findings provide a theoretical basis for understanding the hygroscopic swelling deformation mechanism of red-bed mudstone at various depths.

关键词： Heterogeneous red-bed mudstone Self-sealing band Matric swelling and crack expansion FDEM Microcracks Energy evolution

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Assessment of Agricultural soil Quality Indices Using Mechanistic Models

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Open Journal of soil science 2024年第6期14卷 333-352页

作者： Mohammadali Nikpey Javad Robatjazi Shahabeddin Garmehei Hendra Gonsalve W. Lasar Nguyen Khoi Nghia Benjamin Kwadwo Agyei Department of soil science Faculty of Agriculture Tarbiat Modarres University Tehran Iran Texas A&M AgriLife Research Department of Soil and Crop Sciences Texas A&M University College Station TX USA faculty of soil sciences College of Agriculture Can Tho University Can Tho Vietnam Department of Plant Soil and Microbial Sciences Michigan State University East Lansing MI USA

Assessing soil quality is a critical strategy for diagnosing soil status and anticipating concerns in land use systems for agricultural sustainability. In this study, two soil quality assessment indices, the Integrated Quality Index (IQI) and Nemoro Quality Index (NQI), were employed using two indicator selection methods: Total Data Set (TDS) and Minimum Data Set (MDS), focusing on agricultural fields in Golestan province, Iran. A total of 89 soil samples were collected and analyzed for particle size distribution, organic carbon, calcium carbonate equivalent (CCE), electrical conductivity (EC), pH, and plant-essential nutrients, including nitrogen, phosphorus, potassium, zinc, copper, manganese, and iron. Principal component analysis (PCA) was used to extract MDS from TDS, and geostatistical adaptation and correlation analyses were performed to determine the optimal soil quality evaluation index. Our results show that the exponential model better suits the spatial structure of soil quality indicators (IQIMDS: 0.955). Conformity and correlation analyses indicate that the IQI index outperformed the NQI index in estimating soil quality. The superiority of the TDS technique over the MDS technique in terms of accuracy (IQITDSs kappa: 0.155). Linear relationships between different methods showed a higher correlation coefficient (R2 = 0.43) through the application of IQI. This study suggests the use of IQIMDS to provide a reliable measurement that is particularly useful in assessing the quality of agricultural soil.

关键词： soil Quality Geographic Information System Integrated Quality Index Nemoro Quality Index

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Importance of periphytic biofilms for carbon cycling in paddy fields:A review

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Pedosphere 2024年第1期34卷 36-43页

作者： Lei ZHOU Yonghong WU Junzhuo LIU Pengfei SUN Ying XU Jan DOLFING Robert GMSPENCER Erik JEPPESEN state Key Laboratory of soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Zigui Three Gorges Reservoir Ecosystem Observation and Research Station of Ministry of Water Resources of the People's Republic of ChinaYichang 443605China College of Nanjing University of Chinese Academy of SciencesNanjing 211135China faculty of Energy and Environment Northumbria UniversityNewcastle upon Tyne NE18QHUK Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahassee FL 32306USA Department of Ecoscience&Centre for Water Technology(WATEC) Aarhus UniversityAarhus DK-8000Denmark Sino-Danish Centre for Education and Research Beijing 100049China Limnology Laboratory Department of Biological Sciences and Centre for Ecosystem Research and Implementation(EKOSAM)Middle East Technical UniversityAnkara 06800Turkiye Institute of Marine sciences Middle East Technical UniversityMersin 33731Turkiye

Paddy fields play an important role in global carbon(C) cycling and are an important source of methane(CH_(4)) emissions. Insights into the processes influencing the dynamics of soil organic C(SOC) in paddy fields are essential for maintaining global soil C stocks and mitigating climate change. Periphytic biofilms composed of microalgae, bacteria, and other microorganisms are ubiquitous in paddy fields, where they directly mediate the transfer of elements at the soil-water interface. However, their contributions to C turnover and exchange have been largely neglected. Periphytic biofilms affect and participate in soil C dynamics by altering both abiotic(e.g., pH and redox potential) and biotic conditions(e.g., microbial community composition and metabolism). This review summarizes the contributions of periphytic biofilms to soil C cycling processes, including carbon dioxide fixation, SOC mineralization, and CH_(4) emissions. Future research should be focused on: i) the mechanisms underlying periphytic biofilm-induced C fixation and turnover and ii) quantifying the contributions of periphytic biofilms to soil C uptake, stabilization, and sequestration in paddy fields.

关键词： carbon fixation carbon mineralization carbon sequestration methane emission microbial aggregates soil organic carbon

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A preliminary site selection system for underground hydrogen storage in salt caverns and its application in Pingdingshan,China

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Deep Underground science and Engineering 2024年第1期3卷 117-128页

作者： Liangchao Huang Yanli Fang Zhengmeng Hou Yachen Xie Lin Wu Jiashun Luo Qichen Wang Yilin Guo Wei Sun Sino‐German Research Institute of Carbon Neutralization and Green Development Zhengzhou UniversityZhengzhouChina Institute of Subsurface Energy Systems Clausthal University of TechnologyClausthal ZellerfeldGermany Research Centre of Energy Storage Technologies Clausthal University of TechnologyGoslarGermany Sino‐German Energy Research Center Sichuan UniversityChengduChina state Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanChina faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunmingChina

Large‐scale underground hydrogen storage(UHS)provides a promising method for increasing the role of hydrogen in the process of carbon neutrality and energy *** all the existing storage deposits,salt caverns are recognized as ideal sites for pure hydrogen *** and optimization of site selection for hydrogen storage facilities in salt caverns have become significant *** this article,the software CiteSpace is used to analyze and filter hot topics in published *** on a detailed classification and analysis,a“four‐factor”model for the site selection of salt cavern hydrogen storage is proposed,encompassing the dynamic demands of hydrogen energy,geological,hydrological,and ground factors of salt ***,20 basic indicators for comprehensive suitability grading of the target site were screened using the analytic hierarchy process and expert survey methods were adopted,which provided a preliminary site selection system for salt cavern hydrogen ***,the developed system was applied for the evaluation of salt cavern hydrogen storage sites in the salt mines of Pingdingshan City,Henan Province,thereby confirming its rationality and *** research provides a feasible method and theoretical basis for the site selection of UHS in salt caverns in China.

关键词： analytic hierarchy process(AHP) evaluation index hydrogen storage salt cavern site selection

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vibration reduction effect of the shielding pile based on seismic wave attenuation in shallow underground spaces

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Journal of Earth science 2024年

作者： Qiankuan Wang Shili Qiu Aiguo Xing Xueyong Xu Ye Zhou Yao Cheng Haoshan Zhang Bo Wu Yiwei Liu Mingzhe Zhang Yu Zhuang state Key Laboratory of Ocean Engineering， Shanghai Jiao Tong university state Key Laboratory of Geomechanics and Geotechnical Engineering， Institute of Rock and soil Mechanics， Chinese Academy of sciences North Information Control Research Academy Group CO.， LTD faculty of Engineering， China university of Geosciences

Seismic hazards threaten underground structures and subsequently affect surface buildings， making effective vibration reduction measures crucial in shallow underground spaces. This paper proposes a multi-layer shielding pile based on the seismic wave attenuation theory of refraction dispersion and diffraction loss as a new vibration reduction method. By using the dynamic wave interaction between the unique multi-layer structure of the shielding pile and the seismic wave， a shielding area with significant attenuation of the ground motion is formed to achieve the purpose of vibration reduction. The spectral element method (SEM) with high-order source time function and convolution perfect matching layer (PML) is used to simulate the numerical models of shielding piles with different parameters (including background models and excavation models)， and the characteristics of ground motion and site effect near shielding piles in various models are analyzed. The study reveals the control effect and regulation of the material， size， and shape of the shielding pile on its vibration reduction effect， and determines the shielding pile parameters with the best vibration reduction effect. Shielding piles enriches the vibration reduction measures for structures in shallow underground spaces， and provides a new method for preventing seismic hazards under dynamic load.

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