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Modelling of the elastoplastic behaviour of the bio-cemented soils using an extended Modified Cam Clay model 被引量:1
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作者 Xuerui Wang Christian B.Silbermann +1 位作者 Thomas Nagel Udo Nackenhorst 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2184-2197,共14页
An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the inc... An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the increase of the elastic stiffness,the change of the yield surface due to MICP cementation and the degradation of calcium carbonate bonds during shearing.Specifically,to capture the typical contraction-dilation transition in MICP soils,the original volumetric hardening rule in the MCC model is modified to a combined deviatoric and volumetric hardening rule.The model could reproduce a series of drained triaxial tests on MICP-treated soils with different calcium carbonate contents.Further,we carry out a parametric study and observe numerical instability in some cases.In combination with an analytical analysis,our numerical modelling has identified the benefits and limitations of using MCCbased models in the simulation of MICP-cemented soils,leading to suggestions for further model development. 展开更多
关键词 Microbially induced calcite precipitation(MICP) Elastoplasticity Modified cam clay(MCC) OPENGEOSYS MFront Contraction-dilation transition
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Experimental investigation of the inhibition of deep-sea mining sediment plumes by polyaluminum chloride
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作者 Fengpeng Zhang Xuguang Chen +3 位作者 Jiakang Wei Yangyang Zhang Weikun Xu Hao Li 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第1期91-104,共14页
Deep-sea sediment disturbance may occur when collecting polymetallic nodules,resulting in the creation of plumes that could have a negative impact on the ecological environment.This study aims to investigate the poten... Deep-sea sediment disturbance may occur when collecting polymetallic nodules,resulting in the creation of plumes that could have a negative impact on the ecological environment.This study aims to investigate the potential solution of using polyaluminum chloride(PAC)in the water jet.The effects of PAC are examined through a self-designed simulation system for deep-sea polymetallic nodule collection and sediment samples from a potential deep-sea mining area.The experimental results showed that the optimal PAC dose was found to be 0.75 g/L.Compared with the test conditions without the addition of PAC,the presence of PAC leads to a reduction in volume,lower characteristic turbidity,smaller diffusion velocity,and shorter settling time of the plume.This indicates that PAC inhibits the entire development process of the plume.The addition of PAC leads to the flocculation of mm-sized particles,resulting in the formation of cm-sized flocs.The flocculation of particles decreases the rate of erosion on the seabed by around 30%.This reduction in erosion helps to decrease the formation of plumes.Additionally,when the size of suspended particles increases,it reduces the scale at which they diffuse.Furthermore,the settling velocity of flocs(around 10^(-2) m/s)is much higher that of compared to sediment particles(around 10^(-5) m/s),which effectively reduces the amount of time the plume remains in suspension. 展开更多
关键词 deep-sea mining deep-sea polymetallic nodules Sediment plume Polyaluminum chloride Jet impact Particle flocculation
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Integrated biomarker response to assess toxic impacts of iron and manganese on deep-sea mussel Gigantidas platifrons under a deep-sea mining activity scenario
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作者 Li ZHOU Mengna LI +7 位作者 Zhaoshan ZHONG Minxiao WANG Hao CHEN Chao LIAN Hao WANG Huan ZHANG Lei CAO Chaolun LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第2期522-532,共11页
Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ecosystems.Nevertheless,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient... Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ecosystems.Nevertheless,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient knowledge about the impact of metal exposure on its inhabitants.In this study,deep-sea mussel Gigantidas platifrons,a commonly used deep-sea toxicology model organism,was exposed to manganese(100,1000μg/L)or iron(500,5000μg/L)for 7 d,respectively.Manganese and iron were chosen for their high levels of occurrence within deep-sea deposits.Metal accumulation and a battery of biochemical biomarkers related to antioxidative stress in superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA);immune function in alkaline phosphatase(AKP),acid phosphatase(ACP);and energy metabolism in pyruvate kinase(PK)and hexokinase(HK)were assessed in mussel gills.Results showed that deep-sea mussel G.platifrons exhibited a high capacity to accumulate Mn/Fe.In addition,most tested biochemical parameters were altered by metal exposure,demonstrating that metals could induce oxidative stress,suppress the immune system,and affect energy metabolism of deep-sea mussels.The integrated biomarker response(IBR)approach indicated that the exposure to Mn/Fe had a negative impact on deep-sea mussels,and Mn demonstrated a more harmful impact on deep-sea mussels than Fe.Additionally,SOD and CAT biomarkers had the greatest impact on IBR values in Mn treatments,while ACP and HK were most influential for the low-and high-dose Fe groups,respectively.This study represents the first application of the IBR approach to evaluate the toxicity of metals on deep-sea fauna and serves as a crucial framework for risk assessment of deep-sea mining-associated metal exposure. 展开更多
关键词 MUSSEL metal deep-sea mining BIOMARKER environmental monitoring
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Experimental investigation into effects of the natural polymer and nanoclay particles on the EOR performance of chemical flooding in carbonate reservoirs
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作者 Amir Mohammad Zamani Ashkan Moslemi Kamran Hassani 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期951-961,共11页
This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil... This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil recovery(EOR)in carbonate reservoirs.Thermal gravimetric analysis(TGA)tests were conducted initially in order to evaluate the properties of tragacanth gum.Subsequently,scanning electron microscopy(SEM)and energy-dispersive X-ray(EDX)tests were used to detect the structure of clay particles.In various scenarios,the effects of natural NPs and polymer on the wettability alteration,interfacial tension(IFT)reduction,viscosity improvement,and oil recovery were investigated through contact angle system,ring method,Anton Paar viscometer,and core flooding tests,respectively.The entire experiment was conducted at 25,50,and 75℃,respectively.According to the experimental results,the clay minerals alone did not have a significant effect on viscosity,but the addition of minerals to the polymer solution leads to the viscosity enhancement remarkably,resulting mobility ratio improvement.Among clay NPs,the combination of natural polymer and kaolinite results in increased viscosity at all temperatures.Considerable wettability alteration was also observed in the case of natural polymer and illite NPs.Illite in combination with natural polymer showed an ability in reducing IFT.Finally,the results of displacement experiments revealed that the combination of natural polymer and kaolinite could be the best option for EOR due to its substantial ability to improve the recovery factor. 展开更多
关键词 Chemical flooding Tragacanth gum clay nanoparticle WETTABILITY IFT
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Evolution model and failure mechanisms of rainfall-induced cracked red clay slopes:insights from Xinshao County,China
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作者 JIAO Weizhi ZHANG Ming +4 位作者 LI Peng XIE Junjin PANG Haisong LIU Fuxing YANG Long 《Journal of Mountain Science》 SCIE CSCD 2024年第3期867-881,共15页
Red clay landslides are widely distributed worldwide,resulting in severe loss of life and property.Although rainfall-induced red clay slopes have received extensive attention,the role of cracks in the evolutionary pro... Red clay landslides are widely distributed worldwide,resulting in severe loss of life and property.Although rainfall-induced red clay slopes have received extensive attention,the role of cracks in the evolutionary process of red clay slopes and their connection to failure mechanisms is still poorly understood.A comprehensive approach integrating field investigation,laboratory tests,and numerical simulations was conducted to study the 168 red clay landslides in Xinshao County,China.The results show that red clay is prone to forming cracks at high moisture content due to its low swelling and high shrinkage properties.The failure mode of red clay slopes can be summarized in three stages:crack generation,slope excavation,and slope failure.Furthermore,the retrospective analysis and numerical simulations of the typical landslide in Guanchong indicated that intense rainfall primarily impacts the shallow layer of soil within approximately 0.5 m on the intact slope.However,cracks change the pattern of rainfall infiltration in the slope.Rainwater infiltrates rapidly through the preferential channels induced by the cracks rather than uniformly and slowly from the slope surface.This results in a significant increase in both the depth of infiltration and the saturated zone area of the cracked slope,reaching 3.8 m and 36.2 m^(2),respectively.Consequently,the factor of safety of the slope decreases by 13.4%compared to the intact slope,ultimately triggering landslides.This study can provide valuable insights into understanding the failure mechanisms of red clay slopes in China and other regions with similar geological settings. 展开更多
关键词 Red clay slopes Cracks Preferential flow Failure mechanism
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Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors
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作者 Xingsen Guo Ning Fan +5 位作者 Defeng Zheng Cuiwei Fu Hao Wu Yanjun Zhang Xiaolong Song Tingkai Nian 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第2期211-225,共15页
Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on ... Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures. 展开更多
关键词 deep-sea fluidized slides Pipes Impact forces Shear behavior of slides Interface contact conditions Spatial relation
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Evaluation of red soil-bentonite mixtures for compacted clay liners
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作者 A.S.Devapriya T.Thyagaraj 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期697-710,共14页
Compacted clay liners are an integral part of the waste landfills,which are provided to contain the leachate within the landfills and protect the surrounding environment.Generally,locally available natural soils are u... Compacted clay liners are an integral part of the waste landfills,which are provided to contain the leachate within the landfills and protect the surrounding environment.Generally,locally available natural soils are used for the construction of compacted clay liners if they satisfy the design criteria.However,not all soils in their natural state satisfy all the design criteria for the liner materials.Thus,there is a definite need to modify the locally available natural soils by blending with bentonite to meet the required design criteria for the liners.In view of this,the present study evaluates the suitability of an Indian red soil enhanced with bentonite as a liner material.To achieve this,a series of experiments were carried out using locally available red soil and bentonite.First,the suitability of the red soil was evaluated as a liner material.The experimental results showed that the red soil met all the selection criteria stipulated by the Environmental Protection Agencies(EPAs)for the liners except the hydraulic conductivity criterion.Therefore,the red soil was mixed with bentonite contents of 10%,20%and 30%,and the red soil-bentonite mixtures were evaluated for their suitability for liners in their compacted state.Further,as the liners in the arid and semi-arid regions are subjected to moisture variations due to seasonal moisture fluctuations and other factors,the red soil-bentonite mixtures were subjected to wetdry cycles,and their suitability was evaluated after wet-dry cycles.The experimental results revealed that all the red soil-bentonite mixtures met the stipulated EPA criteria for the liners in the as-compacted state.However,the red soil-bentonite mixtures with 20%and 30%bentonite contents only satisfied the hydraulic conductivity requirement even after wet-dry cycles.The experimental findings were supplemented with the microstructural insights captured through digital camera images,scanning electron microscopy(SEM),and mercury intrusion porosimetry(MIP)studies. 展开更多
关键词 Compacted clay lines Hydraulic conductivity Wet-dry cycles Microstructure
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Multiparameter Numerical Investigation of Two Types of Moving Interactions Between the Deep-Sea Mining Vehicle Track Plate and Seabed Soil:Digging and Rotating Motions
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作者 SUN Peng-fei LYU Hai-ning +1 位作者 YANG Jian-min XU Zhi-yong 《China Ocean Engineering》 SCIE EI CSCD 2024年第3期408-423,共16页
To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions... To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil.In this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging condition.First,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling.Subsequently,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil heterogeneity.The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil.Therefore,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate. 展开更多
关键词 deep-sea mining vehicle rotating motion digging motion track plate-seabed soil interaction CEL numerical method
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Effect of movability of water on the low-velocity pre-Darcy flow in clay soil
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作者 Hui Cheng Fugang Wang +6 位作者 Shengwei Li Xiaotong Guan Guohua Yang Zhongle Cheng Ceting Yu Yilong Yuan Guanhong Feng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3299-3310,共12页
Water seepage in soil is a fundamental problem involving various scientific and engineering fields.According to the literature,low-velocity water seepage in low-permeability porous media,such as clay,does not follow D... Water seepage in soil is a fundamental problem involving various scientific and engineering fields.According to the literature,low-velocity water seepage in low-permeability porous media,such as clay,does not follow Darcy's law,also known as pre-Darcy flow.The formation of immovable water due to water adsorption on the pore wall is believed to be responsible for the formation of pre-Darcy flow.However,this view lacks direct solid evidence.To investigate the pre-Darcy water flow in clay,head permeability experiments are conducted on six clay samples with different densities.The results indicate that water seepage in clay at low hydraulic gradients does not follow Darcy's law.A clear nonlinear relationship between flow velocity and hydraulic gradient is observed.Water flow in clay can be divided into the pre-Darcy flow and Darcy flow regions by the critical hydraulic gradient,which is 10-12 for the Albic soil with dry density between 1.3 g/cm^(3)and 1.8 g/cm^(3).According to the disjoining pressure theory,immovable water due to water adsorption on the pore wall is the primary reason for water flow deviating from Darcy's law in clay.The results indicate that the percentage of movable water ranges from 39.7%to 59.3%for the six samples at a hydraulic gradient of 1.As the hydraulic gradient increases,the percentage of moveable water also increases.Additionally,there is a strong correlation between the percentage of movable water and the variation in hydraulic conductivity with the hydraulic gradient.Furthermore,a quantitative relationship between the percentage of movable water and the hydraulic conductivity has been established.The results of this study suggest that water adsorption on the pore wall not only affects the water movability,but is also closely related to the pre-Darcy flow phenomenon in clay. 展开更多
关键词 Pre-Darcy flow clay Critical hydraulic gradient Water movability analysis
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Performance of composite foundations with different load transfer platforms and substratum stiffness over silty clay
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作者 ZHANG Shuming LIU Yan +3 位作者 YUAN Shengyang LIU Xianfeng JIANG Guanlu LIU Junyan 《Journal of Mountain Science》 SCIE CSCD 2024年第5期1761-1774,共14页
The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of foundations.It is crucial to understand the stress dis... The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of foundations.It is crucial to understand the stress distribution across the embankment width and the behaviour of unreinforced foundations.Thus,five centrifuge tests were conducted to examine the bearing and deformation behaviours of NPRS(Non-Connected Piled Raft Systems)and GRPS(GeosyntheticReinforced Pile-Supported systems)with varying substratum stiffness,then a comparative analysis was conducted on embankment settlement,pressures underneath the embankments,and axial forces along the piles.The results indicated that greater substratum stiffness correlates with reduced settlement and deformation at various depths.Deformation occurring 5 meters from the embankment toe includes settlement in NPRS and upward movement in GRPS.The potential sliding surface is primarily located within the embankment in NPRS,whereas it may extend through both the embankment and foundation in GRPS.The pile-soil stress ratio and efficiency in NPRS are higher than in GRPS across the embankment.The axial force borne by end-bearing piles is significantly greater than that by floating piles.As the buried depth increases,the axial force in GRPS initially rises then declines,whereas in NPRS,it remains relatively constant within a certain range before decreasing.This study aids in assessing the applicability of composite foundations in complex railway environments and provides a reference for procedural measures under similar conditions. 展开更多
关键词 Centrifuge modelling Composite foundation Failure mode Load transfer platform SUBSTRATUM STIFFNESS Silty clay
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Inflow and outflow permeability tests in a very soft clay under low stresses
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作者 J.W.S.Vargas F.A.B.Danziger +1 位作者 F.R.Lopes T.Lunne 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3270-3283,共14页
In situ inflow and outflow permeability tests with the BAT probe at SarapuíII soft clay test site are presented.A description of the BAT permeability test is provided,discussing its advantages and shortcomings,es... In situ inflow and outflow permeability tests with the BAT probe at SarapuíII soft clay test site are presented.A description of the BAT permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low stresses.Pore pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the filter.The role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe installation.Results show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early measurements.Both inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading condition.Various sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests performed.Data are presented concerning the relationship between index parameters and the in situ coefficient of permeability for SarapuíII clay,which plot outside the range of existing databases. 展开更多
关键词 Permeability test Soft clay BAT probe Inflow and outflow tests
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Experimental study on seismic reinforcement of bridge foundation on silty clay landslide with inclined interlayer
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作者 Lei Da Xiao Hanmo +3 位作者 Ran Jianhua Luo Bin Jiang Guanlu Xue Tianlang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第1期193-207,共15页
A shaking table test for a bridge foundation reinforced by anti-slide piles on a silty clay landslide model with an inclined interlayer was performed.The deformation characteristics of the bridge foundation piles and ... A shaking table test for a bridge foundation reinforced by anti-slide piles on a silty clay landslide model with an inclined interlayer was performed.The deformation characteristics of the bridge foundation piles and anti-slide piles were analyzed in different loading conditions.The dynamic response law of a silty clay landslide with an inclined interlayer was summarized.The spacing between the rear anti-slide piles and bridge foundation should be reasonably controlled according to the seismic fortification requirements,to avoid the two peaks in the forced deformation of the bridge foundation piles.The“blocking effect”of the bridge foundation piles reduced the deformation of the forward anti-slide piles.The stress-strain response of silty clay was intensified as the vibration wave field appeared on the slope.Since the vibration intensified,the thrust distribution of the landslide underwent a process of shifting from triangle to inverted trapezoid,the difference in the acceleration response between the bearing platform and silty clay landslide tended to decrease,and the spectrum amplitude near the natural vibration frequency increased.The rear anti-slide piles were able to slow down the shear deformation of the soil in front of the piles and avoid excessive acceleration response of the bridge foundation piles. 展开更多
关键词 silty clay landslide inclined interlayer shaking table test anti-slide pile bridge foundation pile
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Friction Characteristics Between Marine Clay and Construction Materials
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作者 KOU Hailei HUANG Jiaming CHENG Yang 《Journal of Ocean University of China》 CAS CSCD 2024年第2期427-437,共11页
Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils,especially for offshore structures.The interface friction behavior between mar... Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils,especially for offshore structures.The interface friction behavior between marine clay and structural materials with different roughness was studied in this paper by using 3D optical scanning tests,a modified direct shear device and numerical simulation.Relationships between the surface roughness of structures,water content and interface friction angle were presented by model tests.The increase of water contents decreased the interface friction angles.For interfaces with different roughness,the interface friction angles will be smaller than that of the soil when the water content exceeds a certain value.The roughness of the interface and the water content of the soil are mutually coupled to influence the coefficient of friction(COF).This paper proposed a Finite Element Method(FEM)to simulate the interface direct shear tests of structures with different roughness.The surface models with different roughness are established based on the structure data obtained by 3D scanning.The Coupled Eulerian-Lagrangian(CEL)approach was employed to analyse soils sheared by irregular surfaces.The interface behavior for interfaces with different roughness under cyclic shear stresses was analyzed by FEM. 展开更多
关键词 marine clay construction material interface friction behavior surface roughness Finite Element Method
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Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology
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作者 İsmail Cem Akgün Çağın Bolat Ali Gökşenli 《China Foundry》 SCIE EI CAS CSCD 2024年第1期60-70,共11页
In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollu... In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollution.At this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a problem-solver.Owing to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors nowadays.In this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF studies.Additionally,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive responses.Attained results show that PEC particles can be an alternative to expensive hollow spheres used in the previous works.Besides,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength. 展开更多
关键词 die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation
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Soil disturbance evaluation of soft clay based on stress-normalized smallstrain stiffness
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作者 Yanguo Zhou Yu Tian +2 位作者 Junneng Ye Xuecheng Bian Yunmin Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期990-999,共10页
Soil disturbance includes the change of stress state and the damage of soil structure.The field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbanc... Soil disturbance includes the change of stress state and the damage of soil structure.The field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbance directly from these indices.In the present study,the small-strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin equation.The procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed,and then validated by a case study of soft clay ground.Downhole seismic testing in the field,portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded states.It is found that soil sampling disturbance degree by conventional thin-wall sampler is about 30%according to the proposed procedure,which is slightly higher than that from the modified volume compression method proposed by Hong and Onitsuka(1998).And the additional soil disturbance induced by consolidation in laboratory could reach about 50%when the consolidation pressure is far beyond the structural yield stress,and it follows the plastic volumetric strain quite well. 展开更多
关键词 Natural clay Soil sample disturbance Shear wave velocity Small-strain shear modulus Hardin equation
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Effect of NaCl Concentration on the Cumulative Strain and Pore Distribution of Clay under Cyclic Loading
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作者 Xinshan Zhuang Shunlei Xia Ruijie Pan 《Fluid Dynamics & Materials Processing》 EI 2024年第2期447-461,共15页
Clay,as the most common soil used for foundationfill,is widely used in various infrastructure projects.The phy-sical and mechanical properties of clay are influenced by the pore solution environment.This study uses a GD... Clay,as the most common soil used for foundationfill,is widely used in various infrastructure projects.The phy-sical and mechanical properties of clay are influenced by the pore solution environment.This study uses a GDS static/dynamic triaxial apparatus and nuclear magnetic resonance experiments to investigate the effects of cyclic loading on clay foundations.Moreover,the development of cumulative strain in clay is analyzed,and afitting model for cumulative plastic strain is introduced by considering factors such as NaCl solution concentration,con-solidation stress ratio,and cycle number.In particular,the effects of the NaCl solution concentration and con-solidation stress ratio on the pore distribution of the test samples before and after cyclic loading are examined,and the relationship between microscopic pore size and macroscopic cumulative strain is obtained accordingly.Our results show that as the consolidation stress ratio grows,an increasing number of large pores in the soil samples are transformed into small pores.As the NaCl solution concentration becomes higher,the number of small pores gradually decreases,while the number of large pores remains unchanged.Cyclic loading causes the disappearance of the large pores in the samples,and the average pore size before cyclic loading is posi-tively correlated with the axial cumulative strain after cyclic loading.The cumulative strain produced by the soil under cyclic loading is inversely proportional to the NaCl solution concentration and consolidation stress ratio. 展开更多
关键词 Geotechnical engineering clay cyclic loading nuclear magnetic resonance NaCl solution consolidation ratio accumulative strain
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Types,composition and diagenetic evolution of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata:A case study of Mao-1 Member of Middle Permian Maokou Formation,eastern Sichuan Basin,SW China
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作者 SONG Jinmin WANG Jiarui +12 位作者 LIU Shugen LI Zhiwu LUO Ping JIANG Qingchun JIN Xin YANG Di HUANG Shipeng FAN Jianping YE Yuehao WANG Junke DENG Haoshuang WANG Bin GUO Jiaxin 《Petroleum Exploration and Development》 SCIE 2024年第2期351-363,共13页
The types,occurrence and composition of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata of the first member of the Middle Permian Maokou Formation(Mao-1 Member)in eastern Sichuan Basin w... The types,occurrence and composition of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata of the first member of the Middle Permian Maokou Formation(Mao-1 Member)in eastern Sichuan Basin were investigated through outcrop section measurement,core observation,thin section identification,argon ion polishing,X-ray diffraction,scanning electron microscope,energy spectrum analysis and laser ablation-inductively coupled plasma-mass spectrometry.The diagenetic evolution sequence of clay minerals was clarified,and the sedimentary-diagenetic evolution model of clay minerals was established.The results show that authigenic sepiolite minerals were precipitated in the Si4+and Mg2+-rich cool aragonite sea and sepiolite-bearing strata were formed in the Mao-1 Member.During burial diagenesis,authigenic clay minerals undergo two possible evolution sequences.First,from the early diagenetic stage A to the middle diagenetic stage A1,the sepiolite kept stable in the shallow-buried environment lack of Al3+.It began to transform into stevensite in the middle diagenetic stage A2,and then evolved into disordered talc in the middle diagenetic stage B1and finally into talc in the period from the middle diagenetic stage B2to the late diagenetic stage.Thus,the primary diagenetic evolution sequence of authigenic clay minerals,i.e.sepiolite-stevensite-disordered talc-talc,was formed in the Mao-1 Member.Second,in the early diagenetic stage A,as Al3+carried by the storm and upwelling currents was involved in the diagenetic process,trace of sepiolite started to evolve into smectite,and a part of smectite turned into chlorite.From the early diagenetic stage B to the middle diagenesis stage A1,a part of smectite evolved to illite/smectite mixed layer(I/S).The I/S evolved initially into illite from the middle diagenesis stage A2to the middle diagenesis stage B2,and then totally into illite in the late diagenesis stage.Thus,the secondary diagenetic evolution sequence of authigenic clay minerals,i.e.sepiolite-smectite-chlorite/illite,was formed in the Mao-1 Member.The types and evolution of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata are significant for petroleum geology in two aspects.First,sepiolite can adsorb and accumulate a large amount of organic matters,thereby effectively improving the quality and hydrocarbon generation potential of the source rocks of the Mao-1 Member.Second,the evolution from sepiolite to talc is accompanied by the formation of numerous organic matter pores and clay shrinkage pores/fractures,as well as the releasing of the Mg2+-rich diagenetic fluid,which allows for the dolomitization of limestone within or around the sag.As a result,the new assemblages of self-generation and self-accumulation,and lower/side source and upper/lateral reservoir,are created in the Middle Permian,enhancing the hydrocarbon accumulation efficiency. 展开更多
关键词 sepiolite-bearing strata authigenic clay minerals diagenetic evolution Mao First Member of Middle Permian Sichuan Basin
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Cement and Lime Stabilization Effect on the Evolutivity of an Expansive Overconsolidated Clay
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作者 Mohamed Khemissa 《Journal of Civil Engineering and Architecture》 2024年第3期134-140,共7页
This paper presents and analyzes the results of a series of compaction,fragmentability and damage tests performed on an expansive overconsolidated clay treated with cement and lime.This clay was obtained from the urba... This paper presents and analyzes the results of a series of compaction,fragmentability and damage tests performed on an expansive overconsolidated clay treated with cement and lime.This clay was obtained from the urban site of Sidi-Hadjrès city(wilaya of M'sila,Algeria),where significant damages frequently appears in the road infrastructures,roadway systems and light structures.Tests results obtained show that the geotechnical parameters values deduced from these tests are concordant and confirm the evolutivity of this natural clay treated with composed Portland cement or extinct lime and compacted under optimum Proctor conditions. 展开更多
关键词 Expansive clay evolutivity treatment CEMENT LIME fragmentability coefficient damage coefficient
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Clay Materials for Ceramics Application from N’Djamena in the Chad Republic: Mineralogical, Physicochemical and Microstructural Characterization
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作者 Ndjolba Madjihingam Djoda Pagore +3 位作者 Jacques Richard Mache Bebbata Warabi Bertin Pagna Kagonbe Patrick Mountapmbeme Kouotou 《Journal of Materials Science and Chemical Engineering》 2024年第2期31-48,共18页
Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SE... Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO<sub>2</sub> (~57% - 66%), Al<sub>2</sub>O<sub>3 </sub>(~13% - 15%), Fe<sub>2</sub>O<sub>3</sub> (~6% - 10%), TiO<sub>2</sub> (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K<sub>2</sub>O, CaO, Na<sub>2</sub>O). Negligible and trace of MgO (~1%) and P<sub>2</sub>O<sub>5</sub> was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application. 展开更多
关键词 clay Soils Characterization MINERALOGY Physicochemical Properties Ceramic Application
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Improvement of Mechanical Qualities of Clay Material through Coconut Fiber Stabilization
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作者 Boukaré Ouedraogo Abdoulaye Compaore +2 位作者 Moumouni Derra Kalifa Palm Dieudonné Joseph Bahiebo 《Materials Sciences and Applications》 2024年第7期201-212,共12页
The criticisms regularly formulated towards clay or soil, in general, are its weak mechanical qualities and low water quality. Therefore, it is necessary to find techniques to improve the properties of this material, ... The criticisms regularly formulated towards clay or soil, in general, are its weak mechanical qualities and low water quality. Therefore, it is necessary to find techniques to improve the properties of this material, which is widely used worldwide. Here, we propose stabilizing clay with coconut fiber as a solution to enhance its mechanical properties. To do this, we used an experimental method, first determining the geotechnical properties of the clay and then its mechanical properties. The geotechnical study using the Proctor Test revealed that the dry density of the clay is γb = 1.42 g/cm3, and its water content is W = 22.3%. By applying the rolling method, the Atterberg limits were determined: liquid limit Wl = 63.6, plastic limit Wp = 27.9, plasticity index Ip = 35.7, and consistency index Ic = 1.46. With 25 P = 35.7 1.3, according to the water classification, it falls into class A3ts. The mechanical part focused on compression and flexural strengths obtained using a PROETI hydraulic press. We obtained a flexural strength of 0.63 MPa for simple clay (BA);0.89 MPa for clay + 0.25% fiber (BAF1/4);1.68 MPa for clay + 0.5% fiber (BAF1/2);1.87 MPa for clay + 0.75% fiber (BAF3/4);and 3.91 MPa for clay + 1% fiber (BAF1). As for the compression strength, BA = 5.90 MPa, BAF1/4 = 6.395 MPa, BAF1/2 = 6.292 MPa, BAF3/4 = 6.065 MPa, and BAF1 = 5.423 MPa. The addition of fiber has thus improved the mechanical qualities of the simple clay. These stabilized bricks can be used for sustainable and bioclimatic construction, providing higher durability and good comfort. 展开更多
关键词 Compression Strength Flexural Strength Coconut Fiber clay Geotechnical Properties
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