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Impact fracturing of rock-like material using carbon dioxide under different temperatures and pressures

Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 370-384页

作者： Shaobin Hu Zhengyong Yan Chun Zhu Manchao He Shuogang Pang College of Civil and Transportation Engineering Hohai UniversityNanjing210098China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China National Key Laboratory for Disaster Prevention Controland Intelligent Construction and Maintenance of Tunnel EngineeringChina University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing100083China

Unconventional resources (oil, gas, and geothermal) are often buried deep underground within dense rock strata and complex geological structures, making it increasingly difficult to create volumetric fractures through conventional hydraulic fracturing. This paper introduces a novel method of supercritical energetic fluid thermal shock fracturing. It pioneers a CO_(2) deflagration impact triaxial pneumatic fracturing experimental system, using high-strength similar materials to simulate deep, hard rock masses. The study investigates the rock-breaking process and crack propagation patterns under supercritical CO_(2) thermal shock, revealing and discussing the types of thermal shock-induced fractures, their formation conditions, and discrimination criteria. The research indicates that higher supercritical CO_(2) thermal shock pressures and faster pressure release rates facilitate the formation of radial branching fractures, circumferential cracks, and branch cracks. Typically, CO_(2) thermal shock generates 3–5 radial main cracks, which is significantly more than the single main crack formed by hydraulic fracturing. The formation of branched cracks is often caused by compression-shear failure and occurs under relatively harsh conditions, determined by the confining pressure, rock properties, peak thermal shock pressure, and the pressure sustained post-decompression. The findings are expected to offer a safe, efficient, and controllable shockwave method of supercritical fluid thermal shock fracturing for the exploitation of deep unconventional oil and gas resources.

关键词： Cracking mechanism Supercritical CO_(2) True triaxial experimental Impact fracturing

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Comparison of freshwater microbial communities in water and microplastics surfaces:insights from Dongting Lake,China

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Journal of Oceanology and Limnology 2025年第2期43卷 545-558页

作者： Yiming QIU Xiaofeng WEN Ziyi XIANG Zixiang CHEN Ziyi QIU Meinan PENG Shihan ZHONG Jiali HUANG Weicheng ZHOU Lingshi YIN School of Hydraulic and Environmental Engineering Changsha University of Science&TechnologyChangsha 410114China Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province Changsha 410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha 410114China College of Water Resources&Civil Engineering Hunan Agricultural UniversityChangsha 410128China School of Chemistry and Environmental Science Xiangnan UniversityChenzhou 423000China

In recent years,microplastics(MPs)in freshwater lake have been receiving increasing attention;however,the microbial communities on the surface of MPs have not been well *** investigate the potential risk posed by MPs to the lake ecosystem and its surface microbial community structure,MPs samples were collected in September 2023 in the freshwater Dongting Lake,Hunan,China,at five sites,and the differences in bacterial species community composition and structure between MPs and water samples were *** show that MPs(13.71±3.32 items/L)in the samples were mostly black in color,fiber in shape,and PES in composition,and those<0.5 mm in size are *** bacterial composition in water was different from that on *** phylum level,Proteobacteria,Actinobacteria,Cyanobacteria,and Bacteroidetes were dominated in relative abundance in both water and *** was more abundant in MPs than in *** relative abundance of Bacteroidota and Actinobacteriota was significantly lower in MPs than in *** genus level,Pantoea and Pseudomonas were potentially pathogenic genera in MPs *** presence of Cyanobacteria and pathogenic bacteria is undoubtedly a potential risk to the deterioration of the water *** study revealed the difference in the distribution of bacterial community in water and MPs in Dongting Lake and provided new perspectives to further understanding of MPs pollution in freshwater lakes.

关键词： freshwater microplastic(MP) microbial community ecological risk

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Geostatistics-block-based characterization of the relationship between rock mass quality and powder factor and its application on open-pit limit optimization

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International Journal of Mining Science and Technology 2025年第1期35卷 135-147页

作者： Jinduo Li Tianhong Yang Feiyue Liu Shigui Du Wenxue Deng Yong Zhao Honglei Liu Leilei Niu Zhiqiang Xu Center for Rock Instability and Seismicity Research School of Resources&Civil EngineeringNortheastern UniversityShenyang 110819China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China Institute of Rock Mechanics Ningbo UniversityNingbo 315211China Shuguang Gold and Copper Open Pit Mine Zijin Mining Group Company LimitedHunchun 133300China

Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade *** research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder ***,models for blasting cost and mining value were built and employed to optimize the open-pit *** multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength *** model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,***,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the *** study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.

关键词： Geostatistics method Powder factor Open-pit limit optimization Blasting cost Rock mass quality

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Bending behaviour of raw coal gangue concrete-filled steel tubes

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Structures 2025年 76卷

作者： Wu, Xiangjiao Zhao, Hui Wang, Rui Wang, Yunhe Cui, Hongzhi Chen, Man-Tai College of Civil Engineering Taiyuan University of Technology Taiyuan030024 China Shanxi Key Laboratory of Civil Engineering Disaster Prevention and Control Taiyuan University of Technology Taiyuan030024 China College of Civil and Transportation Engineering Shenzhen University Shenzhen China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China

This paper presents an experimental and numerical study on raw coal gangue concrete-filled steel tube (RCGCFST) beams. Six RCGCFST beams were tested to evaluate the effects of raw coal gangue (RCG) replacement level, steel ratio and water-to-cement ratio under bending. The failure modes, moment versus mid-span deflection curves, and moment versus longitudinal strain responses were obtained. Results revealed that all beams exhibited overall bending deformation, with RCG content having a limited effect on the ultimate moment of RCGCFST beams. Finite element (FE) models were subsequently developed and validated against the test results. Parametric studies were conducted to investigate the influence of RCG replacement levels, steel ratios, steel yield strengths, and concrete cubic compressive strengths on the ultimate moment. Finally, six design methods of GB 50936, EC 4, AISC 360, BS5400, T/CECS 625 and ISO 16521 were employed to assess their applicability for RCGCFST specimens. In general, EC 4 provided an accurate prediction for the ultimate moment of RCGCFSTs. © 2025 Institution of Structural Engineers

关键词： Compressive strength

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Measurement of impact failure evolution of coal samples under in-situ water pressure environment: Visualization SHPB experiment and damage model analysis

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Measurement: Journal of the International Measurement Confederation 2025年 253卷

作者： Wang, Kai Bai, Jinwen Feng, Guorui School of Safety and Emergency Management Engineering Taiyuan University of Science and Technology Shanxi Taiyuan030024 China Key Laboratory of Cleaner Intelligent Control on Coal and Electricity Ministry of Education Shanxi Taiyuan030024 China Shanxi Key Laboratory of Mine Rock Strata Control and Disaster Prevention Shanxi Taiyuan030024 China College of Mining Engineering Taiyuan University of Technology Shanxi Taiyuan030024 China

Dynamic load and water storage pressure are key factors influencing the parameter design of coal pillar dams in coal mine groundwater reservoirs. However, the dynamic behaviour of coal pillar dams under real water pressure immersion environments is still unclear. To assess the deformation measurements and failure laws among coal pillar dams under stress waves and in-situ water pressures, a visualized SHPB water pressure loading apparatus was self-designed to research the dynamic response of coal samples within in-situ water pressure environments. The research results show that the self-developed visualized SHPB apparatus could effectively achieve dynamic performance assays on coal samples under in-situ water pressures. In a real water-pressure immersion environment, the dynamic strength of coal samples showed an obvious strain rate effect. There was a good quadratic increasing function relationship between environmental water pressures and dynamic strengths among coal pillar dam samples. The strain evolution of coal pillar dam samples in a real water-pressure immersion environment could be divided into three phases. Increased impact velocity exacerbated the fracture among coal pillar dam samples while the fracture mode gradually shifted from "axial splitting failure" to "compressive shear failure" with increased environmental water pressures. Finally, from a theoretical point of view, a dynamic damage model of coal in real water-pressure conditions was established, which could explain the damage deformation law of coal pillar dam samples under the combined action of dynamic load and environmental water pressure. © 2025

关键词： Fracture mechanics

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Non-synergistic effect of marginal distribution and dependence structure of extremes triggering the future risk of compound dry-hot events in Yellow River, China

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Stochastic Environmental Research and Risk Assessment 2025年 1-14页

作者： Xu, Pengcheng Zhu, Tong Wang, Dong Wang, Yuankun Singh, Vijay P. Lu, Miao Fu, Xiaolei College of Hydraulic Science and Engineering Yangzhou University Yangzhou China Key Laboratory of Surficial Geochemistry Ministry of Education Department of Hydrosciences School of Earth Sciences and Engineering State Key Laboratory of Pollution Control and Resource Reuse Nanjing University Nanjing China School of Water Resources and Hydropower Engineering North China Electric Power University Beijing China Department of Biological and Agricultural Engineering Zachry Department of Civil and Environmental Engineering Texas A & M University College StationTX77843 United States National Water and Energy Center UAE University Al Ain United Arab Emirates National Key Laboratory of Water Disaster Prevention Nanjing Hydraulic Research Institute Nanjing China

Compound dry-hot extremes (CDH) cause devastating socio-economic impacts on society and ecosystems. Univariate risk assessment might not catch the potential impacts of CDH. Considering the negative correlation of average summer temperature and precipitation, this study developed two kinds of copula-based likelihood multiplication index, such as the whole likelihood multiplication index () and the second likelihood multiplication index (), to enumerate the attribution and projection of compound dry-hot events in Yellow River Basin (YRB) of China. Observed datasets show that the areas influenced by the CDH within YRB are increasing, and the most-extreme CDH event was observed several decades ago. Comparison of natural-only and all forcing-based CMIP6 data show that anthropogenic factors are causing the increasing trend of affected areas. Results of analysis showed that changes in the risk of CDH events could depend on not only the temporal variation of the marginal distribution but also the change in the dependence structure between variables. By comparing the difference between and, all grid-based areas in YRB were classified into five cases of combined effects which would help identify the synergistic and non-synergistic contribution of variations in marginal distribution and dependence structure of variables on risk of CDH events. Under Shared Socioeconomic Pathways scenarios (SSPs), the likelihood of concurrent dry-hot extremes is expected to increase in more than half of YRB while small parts of YRB would also experience decreasing likelihood of CDH events with 38.2% of grids under SSP1-2.6, 37.4% under SSP3-7.0 and 36.9% under SSP5-8.5 belonging to case 3 and 6. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.

关键词： Risk assessment

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The lackage in the research of parallel tunnels interaction with a supporting structure in a huge slope: a review

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Discover civil engineering 2025年第1期2卷 1-27页

作者： Suliman, Lojain Liu, Xinrong Zhou, Xiaohan National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas (Chongqing) Chongqing China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing China College of Civil Engineering Chongqing University Chongqing China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing China

Due to urbanization and land constraints in metropolitan areas, there has been an increase in demand for underground construction in recent years. Settlement is always induced by tunneling. Ground settlement as a result of digging shallow tunnels is therefore a frequent occurrence. In order to maintain control over the settlement, it should be able to predict it and take the appropriate safety measures. Even the settlement characteristics due to the excavation of twin the tunnel have been studied extensively. However, the parallel tunnel interaction with other structures in a huge slope has not been studied. This paper aims to review the previous settlement characteristics due to tunneling when parallel tunnels have an interaction process during the excavation. The specific objective of this study is to expand the understanding of settlement behavior in tunneling under large slopes with focusing on the interaction mechanism, which is underexplored in comparison to flat terrains. The capabilities and limitations in the settlement characteristics during the tunneling process have been revised. Furthermore, the gapes in describing the settlement and the lack of studies that accompany the phenomena has been revealed.

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Recycling waste fresh paste through a Dormant & Awaking re-utilization approach

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Materiales de Construccion 2025年第357期75卷

作者： Zong, Z. Chen, P. Qian, X. Li, J. Fang, H. Wang, L. School of Civil Engineering and Architecture Anhui University of Science and Technology Huainan China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology Huainan China

This paper proposed a Dormant & Awaking approach for the management and recycling of waste fresh paste (WFP), a significant byproduct of concrete mixing plants. The approach involves inducing dormancy in WFP using citric acid to slow down cement hydration;whereas calcium aluminate cement (CAC) was utilized to awaken the dormant WFP. Experimental results revealed that treating WFP with citric acid effectively impeded cement hydration, allowing for extended collection and storage time. The addition of CAC facilitates rapid hydration by absorbing and utilizing free water in the pore solutions of cement. Consequently, dormant WFP can be awakened through the rapid precipitation and assembly of hydration products. By adding 17.4% or 26.1% CAC, the compressive strength of WFP at 28 days of curing can be mostly recovered to levels comparable to the blank mixture. A flexible and efficient solution for WFP recycling is thus provided. © 2025 CSIC.

关键词： Hydration

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Prediction of layered UCS of cemented-gangue backfill material using hybrid intelligent models and electrical resistivity segregation monitoring method

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Materials Today Communications 2025年 46卷

作者： Feng, Guorui Zhan, Mengnan Wang, Zehua Qi, Tingye Wang, Yan Mi, Jiachen College of Mining Engineering Taiyuan University of Technology Taiyuan030024 China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan030024 China Shanxi Coal-based Resources Green-efficient Mining Engineering Research Center Taiyuan030024 China Research Center of Green Mining Engineering Technology in Shanxi Province Taiyuan030024 China

The unconfined compressive strength (UCS) of the backfill materials directly affects the safety and stability of the underground space for constructional backfill. Despite advancements in predicting the UCS of backfill materials using machine learning, the influence of segregation on the UCS of backfill materials has been overlooked. This paper proposes the hybrid machine learning model integrated with the electrical resistivity method for the intelligent prediction of the layered UCS of cemented-gangue backfill material (CGBM). The dataset consists of 154 experimental data obtained from electrical resistivity monitoring tests and uniaxial compression tests. key input variables included mass concentration, cement content, fly ash content, fine gangue ratio, and layered segregation index, while the layered UCS of CGBM as output. Four hybrid models—CPO-SVR, CPO-RF, CPO-XGBoost, and CPO-LightGBM—were constructed, with the Crested Porcupine Optimizer (CPO) optimizing model hyperparameters. R², RMSE, and MAE were selected as evaluation metrics for the predictive performance of the hybrid model. The CPO-XGBoost model demonstrated superior performance (R² = 0.957, RMSE = 0.312 MPa, MAE = 0.251 MPa), indicating its high prediction accuracy and stability. Feature importance of the best model, CPO-XGBoost, was analyzed using the Permutation Importance method and SHAP algorithm. The results indicate that cement content has the greatest impact on the model's output, followed by mass concentration, layered segregation index, fine gangue content, and fly ash content. This study offers a reliable framework for real-time prediction of CGBM's mechanical properties and supports decision-making for performance evaluation of backfill body in underground mining. © 2025 Elsevier Ltd

关键词： Compression testing

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Study of the dynamic mechanical behavior and damage mechanisms of water-saturated sandstone subjected to freeze–thaw alternation

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Cold Regions Science and Technology 2025年 237卷

作者： Xie, Haotian Xu, Ying Zheng, Qiangqiang Yu, Meilu Ni, Suqian State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology Huainan232001 China School of Civil Engineering and Architecture Anhui University of Science and Technology Huainan232001 China

To study the mechanical properties and damage mechanisms of rock masses subjected to freeze–thaw cycles under dynamic disturbance, dynamic compression tests were performed on water-saturated sandstone samples subjected to different freeze–thaw cycles and strain rates, and the dynamic strength deterioration and energy evolution characteristics were analyzed. By incorporating Lemaitre's strain equivalence principle, a dynamic damage constitutive model of water-saturated sandstone considering the combined action of freeze–thaw cycling and shock loading was proposed, and its validity was verified. The results indicated that with an increasing number of freeze–thaw cycles, the P-wave velocity, dynamic compressive strength, and elastic modulus of water-saturated sandstone samples gradually decreased. After 120 freeze–thaw cycles, the dynamic compressive strength and elastic modulus at a strain rate of 153.05 s−1 decreased by 21.08 MPa and 3.46 GPa, respectively, compared with those without freeze–thaw cycles. With increasing strain rate, the dynamic compressive strength significantly increased, and the degree of sample fracture progressively intensified. The dissipated energy density showed a positive linear correlation with the strain rate. After 120 freeze–thaw cycles, the dissipated energy density increased from 2.70 J·cm−3 at a strain rate of 153.05 s−1 to 6.36 J·cm−3 at a strain rate of 271.46 s−1. The energy reflectance under shock loading was proposed to define the freeze–thaw destruction variable in terms of the stress wave propagation theory. An exponential negative correlation existed between energy reflectance and dynamic compressive strength. The established constitutive model could effectively reflect the dynamic characteristics of water-saturated sandstone under the combined action of freeze–thaw cycling and shock loading, and the degree of fit with the test curve was high. The research results provide some references for the safe production of surface mines

关键词： Sandstone

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