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Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State key laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep underground engineering China University of Mining and TechnologyXuzhou 221116China State key laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State key laboratory for Geomechanics&Deep underground engineering China University of Mining and Technology(Beijing)Beijing 100083China key laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

Effect of pulse-like ground motions on the seismic performance of slope reinforced by pile-anchor structure: centrifuge model tests and numerical simulations

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Journal of Earth Science 2025年

作者： Xi Xu Wei Wu Xiuli Du key laboratory of Urban Security and Disaster engineering of ministry of education， Beijing University of Technology Institute of geotechnical engineering， University of Natural Resources and Life Sciences

A series of dynamic centrifuge model tests and finite element simulations are conducted to investigate the seismic behavior of slopes reinforced by pile-anchor structures under pulse-like earthquake motions for the first time. The amplification effect and structural behavior， including pile bending moment， pile top displacement， and anchor tension， are considered in the analysis. The findings indicate that pulse-like ground motions give rise to pronounced amplification effect at the pile head， with low-frequency components playing a critical role in the seismic behavior of the structure. This amplification effect is more pronounced under pulse-like motions than in non-pulse cases. Moreover， the pulsatory characteristics of ground motion， particularly the low-frequency components， exert a more significant influence on anti-slide structures than peak ground acceleration (PGA)， leading to higher cumulative energy levels in pulse-like ground motions. Furthermore， the dynamic finite element analysis effectively captures the key phenomena observed in the centrifuge tests， offering valuable insights for optimizing the seismic design of pile-anchor systems.

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Oxalate modification enabled advanced phosphate removal of nZVI:In Situ formed surface ternary complex and altered multi-stage adsorption process

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Journal of Environmental Sciences 2025年第3期149卷 79-87页

作者： Shiyu Cao Jiangshan Li Yanbiao Shi Furong Guo Tingjuan Gao Lizhi Zhang key laboratory of Pesticide&Chemical Biology of ministry of education Institute of Environmental&Applied ChemistryCollege of ChemistryCentral China Normal UniversityWuhan 430079China School of Environmental Science and engineering Shanghai Jiao Tong UniversityShanghai 200240China State key laboratory of Geomechanics and geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China

Nano zero-valent iron(nZVI)is a promising phosphate adsorbent for advanced phosphate ***,the rapid passivation of nZVI and the low activity of adsorption sites seriously limit its phosphate removal performance,accounting for its inapplicability to meet the emission criteria of 0.1 mg P/L *** this study,we report that the oxalate modification can inhibit the passivation of nZVI and alter the multi-stage phosphate adsorption mechanism by changing the adsorption *** expected,the stronger antipassivation ability of oxalate modified nZVI(OX-nZVI)strongly favored its phosphate ***,the oxalate modification endowed the surface Fe(III)sites with the lowest chemisorption energy and the fastest phosphate adsorption ability than the other adsorption sites,by in situ forming a Fe(III)-phosphate-oxalate ternary complex,therefore enabling an advanced phosphate removal *** an initial phosphate concentration of 1.00 mg P/L,pH of 6.0 and a dosage of 0.3 g/L of adsorbents,OX-nZVI exhibited faster phosphate removal rate(0.11 g/mg/min)and lower residual phosphate level(0.02 mg P/L)than nZVI(0.055 g/mg/min and 0.19 mg P/L).This study sheds light on the importance of site manipulation in the development of high-performance adsorbents,and offers a facile surface modification strategy to prepare superior iron-basedmaterials for advanced phosphate removal.

关键词： Oxalate modification Advanced phosphate removal Nano zero-valent iron(nZVI) Surface ternary complex Multi-stage adsorption

Fatigue characteristics of deep excavation-disturbed jinping marble

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Journal of Rock Mechanics and geotechnical engineering 2025年第1期17卷 341-356页

作者： Anlin Zhang Ru Zhang Ting Ai Li Ren Zetian Zhang Jing Xie Chendi Lou Kun Xiao Zeqian Yang State key laboratory of Intelligent Construction&Healthy Operation&Maintenance of Deep underground engineering College of Water Resource&HydropowerSichuan UniversityChengdu 610065China Asian School of the Environment College of ScienceNanyang Technological University639798Singapore key laboratory of Deep Earth Science&engineering Ministry of EducationSichuan UniversityChengdu 610065China State key laboratory of Hydraulics&Mountain River engineering Sichuan UniversityChengdu 610065China Institute for Disaster Management&Reconstruction Sichuan UniversityChengdu 610065China

Deep rocks encountered in underground engineering are frequently in complex in situ environments and experience both excavation disturbance during construction and cyclic loading throughout the long-term operation. Understanding the fatigue behavior of excavation-disturbed rocks in complex stress environments is critical for assessing the long-term stability of deep rock structures. Hence, an experimental method has been developed to capture the fatigue damage process of rocks while considering the in situ environment and excavation disturbance. Using this method, a series of triaxial fatigue damage experiments were conducted on Jinping deep marble samples from various in situ environments of 100 m, 1000 m, 1800 m, and 2400 m to better understand the variation in fatigue characteristics at different depths. With increasing depth, the samples experienced more cycles and greater fatigue deformation before failure. Further insights were gained into the fatigue damage behavior in terms of stiffness degradation, energy dissipation and irreversible strain accumulation. A decrease in the elastic modulus and an increase in the dissipated energy and irreversible strain exhibit an evolution pattern of initial→stabilization→acceleration, reflecting the nonlinear fatigue process that occurs inside marble. With increasing depth, marble samples have longer fatigue lives but exhibit more significant stiffness loss, energy dissipation and irrecoverable deformation accumulation;thus, evaluating the instability of deep rock structures solely using fatigue life alone is inadequate. Moreover, the previously reported inverted S-shaped evolution of fatigue damage was observed, and it was found that an increase in depth leads to an earlier onset of the accelerated fatigue damage stage with greater dominance of fatigue failure. Based on the nonlinear strain, loading cycle variable and fatigue life, a highly accurate nonlinear fatigue model was developed to describe the complete inverted S-

关键词： Excavation-disturbed rock In situ environment Fatigue behavior Damage model

Assessing ground stability of a vertical backfilled stope considering creep behaviors of surrounding rocks

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Journal of Rock Mechanics and geotechnical engineering 2025年第1期17卷 187-199页

作者： Ruofan Wang Lang Liu Mengbo Zhu Huafu Qiu Bingbing Tu Huisheng Qu Hao Cui Faculty of Energy engineering Xi’an University of Science and TechnologyXi’an710054China key laboratory of Western Mines and Hazards Prevention Ministry of Education of ChinaXi’an710054China Faculty of Science Xi’an University of Science and TechnologyXi’an710054China PowerChina Huadong engineering Corporation Limited Hangzhou311122China

Backfill is often employed in mining operations for ground support,with its positive impact on ground stability acknowledged in many underground ***,existing studies have predominantly focused only on the stress development within the backfill material,leaving the influence of stope backfilling on stress distribution in surrounding rock mass and ground stability largely ***,this paper presents numerical models in FLAC3D to investigate,for the first time,the time-dependent stress redistribution around a vertical backfilled stope and its implications on ground stability,considering the creep of surrounding rock *** the Soft Soil constitutive model,the compressibility of backfill under large pressure was *** is found that the creep deformation of rock mass exercises compression on backfill and results in a less void ratio and increased modulus for fill *** compacted backfill conversely influenced the stress distribution and ground stability of rock mass which was a combined effect of wall creep and compressibility of *** the increase of time or/and creep deformation,the minimum principal stress in the rocks surrounding the backfilled stope increased towards the pre-mining stress state,while the deviatoric stress reduces leading to an increased factor of safety and improved ground *** improvement effect of backfill on ground stability increased with the increase of mine depth and stope height,while it is also more pronounced for the narrow stope,the backfill with a smaller compression index,and the soft rocks with a smaller viscosity ***,the results emphasize the importance of minimizing empty time and backfilling extracted stope as soon as possible for ground *** of filling gap height enhances the local stability around the roof of stope.

关键词： Ground stability Time dependency Creep Surrounding rocks Backfilled stope

laboratory assessment of tensile properties of root-soil composite of Amorpha fruticose

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Journal of Mountain Science 2025年第3期22卷 1062-1074页

作者： Tao, Gaoliang Yang, Chuanhui Chen, Qingsheng Nimbalkar, Sanjay Xiao, Henglin Wang, Qing Innovation Demonstration Base of Ecological Environment geotechnical and Ecological Restoration of Rivers and Lakes Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes Ministry of Education Hubei University of Technology Wuhan 430068 China School of Intelligent Construction Wuchang University of Technology Wuhan 430223 China School of Civil and Environmental engineering University of Technology Sydney (UTS) Ultimo 2007 NSW Australia

Plant root systems serve as a natural reinforcing material, significantly improving soil stability. Furthermore, the tensile strength of soil is crucial in mitigating the formation of cracks. Consequently, this study aims to investigate the influence of plant roots on the tensile strength of soil. For this investigation, Amorpha fruticose was selected due to its large root diameter and the ease of root extraction. Indoor tensile tests were conducted on individual roots and root-soil complexes under three varying factors. The results indicate a power law relationship between root diameter and tensile strength. Increased root content and dry density notably enhance the tensile strength of the root-soil complex while roots mitigate damage associated with soil brittleness. When root content increases from 0 to 10, the maximum enhancement in tensile strength of the root-soil complex reaches 42.3 kPa. The tensile strength of the root-soil complex at a dry density of 1.7 g/cm3 is four to five times greater than that of the complex at a dry density of 1.4 g/cm3. Moreover, as moisture content increases, the tensile strength of the root-soil complex initially rises before declining, with an increase range of 7.7–35.8 kPa. These findings provide a scientific basis for understanding the role of vegetation roots in soil tensile strength and for guiding slope reinforcement strategies. © Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2025.

关键词： Dry density Moisture content Root content Root soil complex Tensile strength

3-D CONSOLIDATION ANALYSIS OF LAYERED SOIL WITH ANISOTROPIC PERMEABILITY USING ANALYTICAL LAYER-ELEMENT METHOD

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Acta Mechanica Solida Sinica 2013年第1期26卷 62-70页

作者： Zhiyong Ai Yichong Cheng Department of geotechnical engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationTongji University

Starting with governing equations of a saturated soil with anisotropic permeability and based on multiple integral transforms, an analytical layer-element equation is established explicitly in the Laplace-Fourier transformed domain. A global matrix of layered soil can be obtained by assembling a set of analytical layer-elements, which is further solved in the transformed domain by considering boundary conditions. The numerical inversion of LaplaceFourier trans- form is employed to acquire the actual solution. Numerical analysis for 3-D consolidation with anisotropic permeability of a layered soil system is presented, and the influence of anisotropy of permeability on the consolidation behavior is discussed.

关键词： analytical layer-element 3-D consolidation anisotropic permeability multiple integral transforms

Rockburst prediction based on multi-featured drilling parameters and extreme tree algorithm for full-section excavated tunnel faces

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Journal of Rock Mechanics and geotechnical engineering 2025年第1期17卷 258-274页

作者： Wenhao Yi Mingnian Wang Qinyong Xia Yongyi He Hongqiang Sun School of Civil engineering Southwest Jiaotong UniversityChengdu610031China key laboratory of Transportation Tunnel engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu610031China China Railway Third Bureau Group Co. Ltd.Taiyuan030001China

The suddenness, uncertainty, and randomness of rockbursts directly affect the safety of tunnel construction. The prediction of rockbursts is a fundamental aspect of mitigating or even eliminating rockburst hazards. To address the shortcomings of the current rockburst prediction models, which have a limited number of samples and rely on manual test results as the majority of their input features, this paper proposes rockburst prediction models based on multi-featured drilling parameters of rock drilling jumbo. Firstly, four original drilling parameters, namely hammer pressure (Ph), feed pressure (Pf), rotation pressure (Pr), and feed speed (VP), together with the rockburst grades, were collected from 1093 rockburst cases. Then, a feature expansion investigation was performed based on the four original drilling parameters to establish a drilling parameter feature system and a rockburst prediction database containing 42 features. Furthermore, rockburst prediction models based on multi-featured drilling parameters were developed using the extreme tree (ET) algorithm and Bayesian optimization. The models take drilling parameters as input parameters and rockburst grades as output parameters. The effects of Bayesian optimization and the number of drilling parameter features on the model performance were analyzed using the accuracy, precision, recall and F1 value of the prediction set as the model performance evaluation indices. The results show that the Bayesian optimized model with 42 drilling parameter features as inputs performs best, with an accuracy of 91.89%. Finally, the reliability of the models was validated through field tests.

关键词： Rockburst prediction Drilling parameters Feature system Extreme tree(ET) Bayesian optimization

Limit analysis on seismic stability of anisotropic and nonhomogeneous slopes with anti-slide piles

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Science China(Technological Sciences) 2018年第1期61卷 140-146页

作者： GONG WeiBing LI JingPei LI Lin Department of geotechnical engineering Tongji University key laboratory of geotechnical and underground engineering of ministry of education Tongji University

This study employs the limit analysis method to evaluate the seismic stability of anisotropic and nonhomogeneous slopes stabilized with anti-slide piles. The pseudo-static approach is used to simplify the earthquake load. The yield seismic acceleration factor is obtained from the optimization procedure and the results are verified with the published data. Then, the seismically-unstable slope is reinforced with anti-slide piles, and the seismic stability of the reinforced slope is explored. The results show that the anisotropy and nonhomogeneity of soils have significant effects on the stabilizing force required from the anti-slide piles and the optimal location of the pile is near the toe of the slope.

关键词： limit analysis pseudo-static approach anti-slide pile optimal location