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Effect of non-uniform swelling on coal multiphysics during gas injection: The triangle approach
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作者 Yifan Huang Jishan Liu +2 位作者 Yaoyao Zhao Derek Elsworth Yee-Kwong Leong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1362-1372,共11页
In current dual porosity/permeability models,there exists a fundamental assumption that the adsorption-induced swelling is distributed uniformly within the representative elementary volume (REV),irrespective of its in... In current dual porosity/permeability models,there exists a fundamental assumption that the adsorption-induced swelling is distributed uniformly within the representative elementary volume (REV),irrespective of its internal structures and transient processes.However,both internal structures and transient processes can lead to the non-uniform swelling.In this study,we hypothesize that the non-uniform swelling is responsible for why coal permeability in experimental measurements is not only controlled by the effective stress but also is affected by the adsorption-induced swelling.We propose a concept of the swelling triangle composed of swelling paths to characterize the evolution of the non-uniform swelling and serve as a core link in coupled multiphysics.A swelling path is determined by a dimensionless volumetric ratio and a dimensionless swelling ratio.Different swelling paths have the same start and end point,and each swelling path represents a unique swelling case.The swelling path as the diagonal of the triangle represents the case of the uniform swelling while that as the two perpendicular boundaries represents the case of the localized swelling.The paths of all intermediate cases populate inside the triangle.The corresponding relations between the swelling path and the response of coal multiphysics are established by a non-uniform swelling coefficient.We define this method as the triangle approach and corresponding models as swelling path-based ones.The proposed concept and models are verified against a long-term experimental measurement of permeability and strains under constant effective stress.Our results demonstrate that during gas injection,coal multiphysics responses have a close dependence on the swelling path,and that in both future experiments and field predictions,this dependence must be considered. 展开更多
关键词 Transient process HETEROGENEITY swelling triangle swelling path Non-uniform swelling coefficient
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Swelling pressure evolution characterization of strong expansive soil considering the influence of reserved expansion deformation
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作者 LI Tianguo KONG Lingwei +1 位作者 GUO Aiguo YAN Junbiao 《Journal of Mountain Science》 SCIE CSCD 2024年第1期252-270,共19页
Numerous engineering cases have demonstrated that the expansive soil channel slope remains susceptible to damage with the implementation of a rigid or closed protective structure. It is common for the protective struc... Numerous engineering cases have demonstrated that the expansive soil channel slope remains susceptible to damage with the implementation of a rigid or closed protective structure. It is common for the protective structure to experience bulging failure due to excessive swelling pressure. To investigate the swelling pressure properties of expansive soil, the constant volume test was employed to study the influence of water content and reserved expansion deformation on the characteristics of swelling pressure in strong expansive soils, and also to explore the evolution mechanism of the swelling pressure. The findings demonstrate that the swelling pressure-time curve can be classified into swelling pressure-time softening and swelling pressure-time stability type. The swelling pressuretime curve of the specimen with low water content is the swelling pressure-time softening type, and the softening level will be weakened with increasing reserved expansion deformation. Besides, the maximum swelling pressure Psmax decreases with increasing water content and reserved expansion deformation, especially for expansion ratio η from 24% to 37%. The reserved deformation has little effect on reducing Psmax when it is beyond 7% of the expansion rate. The specimen with low water content has a more homogeneous structure due to the significant expansion-filling effect, and the fracture and reorganization of the aggregates in the specimens with low water content cause the swelling pressure-time softening behavior. In addition, the proposed swelling pressure-time curve prediction model has a good prediction on the test results. If necessary, a deformation space of about 7% expansion rate is recommended to be reserved in the engineering to reduce the swelling pressure except for keeping a stable water content. 展开更多
关键词 Expansive soil swelling pressure Reserved expansion deformation Water content
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An analytical transient coal permeability model:Sorption non-equilibrium index-based swelling switch
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作者 Xingxing Liu Jishan Liu +2 位作者 Liang Chen Jinchang Sheng Huimin Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1175-1191,共17页
Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been... Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been considered in current analytical permeability models.This study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch model.The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model.Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions.Model verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these models.This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions.It provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams. 展开更多
关键词 Coal permeability Sorption swelling switch Sorption non-equilibrium Boundary conditions
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Microstructure and water-swelling mechanism of red-bed mudstone in the Xining region,Northeastern Tibetan Plateau
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作者 Huan Guan Yong Ren +5 位作者 Sixiang Ling Xiyong Wu Tao Yu Xian Li Sen Wang Chunwei Sun 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2537-2551,共15页
This paper examines the effect of the microstructure and electrical conductivity(EC)on the swelling ratio and pressure in red-bed mudstone sampled from arid areas in the Xining region in the northeastern Tibetan Plate... This paper examines the effect of the microstructure and electrical conductivity(EC)on the swelling ratio and pressure in red-bed mudstone sampled from arid areas in the Xining region in the northeastern Tibetan Plateau.A series of laboratory tests,including swelling experiments,X-ray diffraction(XRD),and scanning electron microscope(SEM),was carried out for mechanical and microstructural analysis.The coupled influence of the EC and microstructural parameters on the expansion ratio and pressure was investigated,and the weight coefficients were discussed by the entropy weight method.The results revealed an increasing exponential trend in EC,and the maximum swelling speed occurred at an EC of approximately 10 mS/cm.In addition,a method for predicting the expansion potential is proposed based on the microstructure,and its reliability is verified by comparing with swelling experimental results.In addition,according to the image analysis results,the ranges of the change in the clay minerals content(CMC),the fractal dimension(FD),the average diameter(AD)of pores,and the plane porosity(PP)are 23.75%e53%,1.08e1.17,7.53e22.45 mm,and 0.62%e1.25%,respectively.Moreover,mudstone swelling is negatively correlated with the plane porosity,fractal dimension and average diameter and is linearly correlated with the clay mineral content.Furthermore,the weight values prove that the microstructural characteristics,including FD,AD,and PP,are the main factors influencing the expansion properties of red-bed mudstones in the Xining region.Based on the combination of macro and micro-analyses,a quantitative analysis of the swelling process of mudstones can provide a better reference for understanding the mechanism of expansion behavior. 展开更多
关键词 MUDSTONES MICROSTRUCTURE swelling characteristics Electrical conductivity(EC) Scanning electron microscope Water-swelling
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Application of multi-algorithm ensemble methods in high-dimensional and small-sample data of geotechnical engineering:A case study of swelling pressure of expansive soils
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作者 Chao Li Lei Wang +1 位作者 Jie Li Yang Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1896-1917,共22页
Geotechnical engineering data are usually small-sample and high-dimensional,which brings a lot of challenges in predictive modeling.This paper uses a typical high-dimensional and small-sample swell pressure(P_(s))data... Geotechnical engineering data are usually small-sample and high-dimensional,which brings a lot of challenges in predictive modeling.This paper uses a typical high-dimensional and small-sample swell pressure(P_(s))dataset to explore the possibility of using multi-algorithm hybrid ensemble and dimensionality reduction methods to mitigate the uncertainty of soil parameter prediction.Based on six machine learning(ML)algorithms,the base learner pool is constructed,and four ensemble methods,Stacking(SG),Blending(BG),Voting regression(VR),and Feature weight linear stacking(FWL),are used for the multi-algorithm ensemble.Furthermore,the importance of permutation is used for feature dimensionality reduction to mitigate the impact of weakly correlated variables on predictive modeling.The results show that the proposed methods are superior to traditional prediction models and base ML models,where FWL is more suitable for modeling with small-sample datasets,and dimensionality reduction can simplify the data structure and reduce the adverse impact of the small-sample effect,which points the way to feature selection for predictive modeling.Based on the ensemble methods,the feature importance of the five primary factors affecting P_(s) is the maximum dry density(31.145%),clay fraction(15.876%),swell percent(15.289%),plasticity index(14%),and optimum moisture content(13.69%),the influence of input parameters on P_(s) is also investigated,in line with the findings of the existing literature. 展开更多
关键词 Expansive soils swelling pressure Machine learning(ML) Multi-algorithm ensemble Sensitivity analysis
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Effect of drying cracks on swelling and self-healing of bentonite-sand blocks used as engineered barriers for radioactive waste disposal
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作者 Yu Tan Guangping Zhou +2 位作者 Huyuan Zhang Xiaoya Li Ping Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1776-1787,共12页
Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to... Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks. 展开更多
关键词 Beishan groundwater chemistry Bentonite buffer Drying cracks High-level radioactive waste(HLW) SELF-HEALING swelling
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Swelling behaviors of heterogeneous red-bed mudstone subjected to different vertical stresses
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作者 Kang Huang Zhangjun Dai +3 位作者 Chengzeng Yan Fei Yu Wei Zhang Shanxiong Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1847-1863,共17页
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... 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 considered.The microcrack behavior and energy evolution of mudstone during hygroscopic swelling deformation under different vertical stresses are studied.The results show that the axial swelling strain of mudstone decreases with increase of the vertical stress.At low vertical stresses,moisture absorption in mudstone leads to formation of cracks caused by hydration-induced expansion.Under high vertical stresses,a muddy sealing zone forms on the mudstone surface,preventing further water infiltration.The simulation results of mudstone swelling deformation also demonstrate that it involves both swelling of the mudstone matrix and swelling caused by crack expansion.Notably,crack expansion plays a dominant role in mudstone swelling.With increasing vertical stress,the cracks in mudstone change from tensile cracks to shear cracks,resulting in a significant reduction in the total number of cracks.While 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 mudstone.The findings provide a theoretical basis for understanding the hygroscopic swelling deformation mechanism of red-bed mudstone at various depths. 展开更多
关键词 Heterogeneous red-bed mudstone Self-sealing band Matric swelling and crack expansion FDEM MICROCRACKS Energy evolution
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Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent Resin
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作者 马砺 WANG Xin +2 位作者 LIU Xixi WEI Gaoming GUO Ying 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期790-799,共10页
Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,p... Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model. 展开更多
关键词 super absorbent resin swelling kinetics water absorption graft copolymerization hydroxypropyl methyl cellulose
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Vulvar Swelling in a 12-Year-Old Girl: An Early Manifestation of Crohn’s Disease
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作者 Stefania Rendina Dolores Ferrara +3 位作者 Rosanna Mamone Sara Isoldi Massimo Zeccolini Francesco Esposito 《Case Reports in Clinical Medicine》 2024年第7期219-226,共8页
Vulvar Crohn’s disease (VCD) is a rare complication of Crohn’s disease, especially in pediatric population. An early diagnosis can result difficult if the complication does not present in conjunction with the classi... Vulvar Crohn’s disease (VCD) is a rare complication of Crohn’s disease, especially in pediatric population. An early diagnosis can result difficult if the complication does not present in conjunction with the classic gastrointestinal symptoms that characterize this disease. In this study we present the case of a 12-year-old girl whose initial symptom of Crohn’s disease was a symptomatic vulvar swelling promoted by a rectovaginal fistula. We also provide an overview of Crohn’s disease and the vulvar changes found in the course of this disease. 展开更多
关键词 Recto-Vaginal Fistula Vulvar swelling Metastatic Crohn’s Disease
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Clinical Observation of Chinese Medicinal Prescriptions for Swelling and Pain in The Postoperative Treatment of Mixed Hemorrhoids
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作者 Yuru Duan Guangliang Xu +3 位作者 Lei Ge Wei Zhang Xu Zhang Yi Yang 《Journal of Clinical and Nursing Research》 2024年第3期101-107,共7页
Objective:To observe the clinical effect of traditional Chinese medicine(TCM)on reducing swelling and pain in patients with mixed hemorrhoids.Methods:Sixty patients with mixed hemorrhoids who were admitted to the Hosp... Objective:To observe the clinical effect of traditional Chinese medicine(TCM)on reducing swelling and pain in patients with mixed hemorrhoids.Methods:Sixty patients with mixed hemorrhoids who were admitted to the Hospital of Traditional Chinese Medicine of Qiqihar from January 2023 to January 2024 were selected and divided into two groups.The treatment group(n=30)was treated with mixed hemorrhoid ligation combined with traditional Chinese swelling and pain medicine,and the control group(n=30)was only treated with mixed hemorrhoid ligation.The pain level,edema score,and prognosis of the two groups after the intervention were analyzed.The clinical efficacy was used as the evaluation criterion to compare the clinical effects of different treatment options.Results:After the treatment,the pain score,edema score,and prognostic wound score of the treatment group were all lower than those of the control group(P 0.05).The total clinical effectiveness of the treatment group(100%)was higher than that of the control group(76.67%),(χ^(2)=4.2857,P<0.05).Conclusion:The application of traditional Chinese swelling and pain medicine in treating patients with mixed hemorrhoids effectively reduced the patient’s pain,reduced the degree of wound edema,promoted wound healing,and improved the patient’s prognosis.The curative effect was significant and had a positive impact. 展开更多
关键词 Chinese herbal prescriptions for reducing swelling and pain Mixed hemorrhoids Postoperative treatment
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Numerical analysis of matrix swelling and its effect on microstructure of digital coal and its associated permeability during CO_(2)-ECBM process based on X-ray CT data 被引量:1
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作者 Hui-Huang Fang Zhang-Fei Wang +1 位作者 Shu-Xun Sang Yan-Hui Huang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第1期87-101,共15页
Matrix swelling effect will cause the change of microstructure of coal reservoir and its permeability,which is the key factor affecting the engineering effect of CO_(2)-ECBM technology.The Sihe and Yuwu collieries are... Matrix swelling effect will cause the change of microstructure of coal reservoir and its permeability,which is the key factor affecting the engineering effect of CO_(2)-ECBM technology.The Sihe and Yuwu collieries are taken as research objects.Firstly,visualization reconstruction of coal reservoir is realized.Secondly,the evolution of the pore/fracture structures under different swelling contents is discussed.Then,the influence of matrix phase with different swelling contents on permeability is discussed.Finally,the mechanism of swelling effect during the CO_(2)-ECBM process is further discussed.The results show that the intra-matrix pores and matrix-edge fractures are the focus of this study,and the contacting area between matrix and pore/fracture is the core area of matrix swelling.The number of matrix particles decreases with the increase of size,and the distribution of which is isolated with small size and interconnected with large size.The swelling effect of matrix particles with larger size has a great influence on the pore/fracture structures.The number of connected pores/fractures is limited and only interconnected in a certain direction.With the increase of matrix swelling content,the number,porosity,width,fractal dimension,surface area and volume of pores/fractures decrease,and their negative contribution to absolute permeability increases from 0.368% to 0.633% and 0.868%-1.404%,respectively.With the increase of swelling content,the number of intra-matrix pores gradually decreases and the pore radius becomes shorter during the CO_(2)-ECBM process.The matrix continuously expands to the connected fractures,and the width of connected fractures gradually shorten.Under the influence of matrix swelling,the bending degree of fluid flow increases gradually,so the resistance of fluid migration increases and the permeability gradually decreases.This study shows that the matrix swelling effect is the key factor affecting CBM recovery,and the application of this effect in CO_(2)-ECBM process can be discussed. 展开更多
关键词 Matrix swelling CO_(2)-ECBM Absolutely permeability Numerical analysis X-ray CT Qinshui Basin
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Wetting-drying-freezing-thawing cycle effect on the hydro-mechanical behaviour of Yanji swelling mudstone
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作者 Zhixiong Zeng Lingwei Kong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2746-2756,共11页
Swelling geomaterials in northwestern and northeastern China are exposed to both seasonal wettingdrying(DW)and freezing-thawing(FT)processes.The influence of full-process wetting-dryingfreezing-thawing(WDFT)cycles on ... Swelling geomaterials in northwestern and northeastern China are exposed to both seasonal wettingdrying(DW)and freezing-thawing(FT)processes.The influence of full-process wetting-dryingfreezing-thawing(WDFT)cycles on their hydro-mechanical behaviour has not been well investigated.In this study,a series of swelling and compression tests was conducted on Yanji weathered mudstone subjected to different WD,FT and WDFT processes and the effects of seasonal processes and cyclic number on the swelling strain,compression index,rebound index and hydraulic conductivity were experimentally determined.With the increasing WD,FT and WDFT cycles,the starting time of primary swelling decreased first due to the increasing water infiltration with the appearance of large pores,and then increased because of the decreasing swelling potential of compact aggregates after two cycles.Moreover,as the cyclic number increased,the final swelling strain declined.Upon loading,the specimens after cyclic processes exhibited a smaller compression index at low stresses due to their smaller interparticle distance after swelling,but a larger one owing to the collapse of large pores and cracks at high vertical stresses.After unloading,the rebound index decreased with the increase of cyclic number due to the irreversible collapse of large pores and cracks.The hydraulic conductivity increased with the increasing cyclic number at low vertical stresses(large void ratios).With the further increase of vertical stress,the increase of hydraulic conductivity induced by cyclic processes became indiscernible.Moreover,a comparison among three processes suggested that the WDFT process exerted a more pronounced influence on the hydro-mechanical behaviour of Yanji mudstone than the separate WD or FT process. 展开更多
关键词 swelling mudstone Seasonal processes swelling deformation COMPRESSIBILITY Hydraulic conductivity
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Transient swelling-induced finite bending of hydrogel-based bilayers:analytical and FEM approaches
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作者 A.AMIRI M.BANIASSADI M.BAGHANI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第2期273-288,共16页
Hydrogels with their time-dependent intrinsic behaviors have recently been used widely in soft structures as sensors/actuators.One of the most interesting structures is the bilayer made up of hydrogels which may under... Hydrogels with their time-dependent intrinsic behaviors have recently been used widely in soft structures as sensors/actuators.One of the most interesting structures is the bilayer made up of hydrogels which may undergo swelling-induced bending.In this work,by proposing a semi-analytical method,the transient bending of hydrogel-based bilayers is investigated.Utilizing nonlinear solid mechanics,a robust semi-analytical solution is developed which captures the transient finite bending of hydrogel-based bilayers.Moreover,the multiphysics model of the hydrogels is implemented in the finite element method(FEM) framework to verify the developed semi-analytical procedure results.The effects of different material properties are investigated to illustrate the nonlinear behavior of these structures.The von-Mises stress contour extracted from FEM shows that the critical area of these soft structures is at the interface of the layers which experiences the maximum stress,and this area is most likely to rupture in large deformations. 展开更多
关键词 HYDROGEL transient swelling bilayer multiphysics finite bending
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Factors Predisposing and Triggering the Phenomenon of Shrinkage-Swelling of Clay Soils in the Urban Center of Diamniadio
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作者 Khadim Faye Fatou Samb +1 位作者 Pape Sanou Faye Yves Berthaud 《Geomaterials》 CAS 2023年第2期23-34,共12页
The phenomena of shrinkage and swelling of clay induce damage to housing structures every year. Precipitation, climatic changes and drought are the cause of wall cracks due to subsidence or swelling of the supporting ... The phenomena of shrinkage and swelling of clay induce damage to housing structures every year. Precipitation, climatic changes and drought are the cause of wall cracks due to subsidence or swelling of the supporting soil. This movement alters the balance between the soil and the structures. To explain this defection, the soil is made up of three elements: the solid, the liquid and the gas. Sometimes in a natural way or following a human intervention, one of these elements undergoes an abnormal variation that causes the loss of the balance between land and works. It is in this sense that this article deals on the one hand with the factors of predisposition and triggering of the phenomena of shrinkage-swelling of the clay soils of Diamniadio and on the other hand, the factors of aggravation linked to the lithological heterogeneity and the variation in the thickness of the layers susceptible to shrinkage-swelling. The studies carried out have enabled a deeper understanding of the behavior of expansive soils following their interactions with climate, vegetation, hydrology, hydrogeology, constructions among others, but also the influence of lateral and vertical variations of fine soil facies. 展开更多
关键词 swelling Clays Expansive Soil Shrinkage-swelling Desiccation Cracks Diamniadio
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Nano-CaO_(2)Promotes the Release of Carbon Sources from Municipal Sludge and the Preparation of Double-Network Hydrogels with High Swelling Ratios
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作者 Yalin Li Yu Huang +4 位作者 Lei Liu Haozhao Liu Haiyang He Dongxue Lu Tingting Dong 《Journal of Renewable Materials》 SCIE EI 2023年第3期1237-1253,共17页
In this study,hydrogels were prepared from municipal sludge to recycle and realize the value-added utilization of the carbon components in this abundant waste material.The carbon sources were extracted from the munici... In this study,hydrogels were prepared from municipal sludge to recycle and realize the value-added utilization of the carbon components in this abundant waste material.The carbon sources were extracted from the municipal sludge using synthesised nano CaO_(2)as an oxidant,and the carbon sources were graft copolymerised with acrylic acid monomer using N,N′-methylenebisacrylamide as a crosslinking agent and ammonium persulfate as an initiator.The factors influencing the hydrogel preparation were investigated by single-factor experiments.Based on the results of the single-factor experiments,a hydrogel with a swelling ratio of up to 19768.4%at 12 h was prepared with an oxidant dosage of 0.20 g,a monomer dosage of 5.8 g,a neutralisation degree of the monomer of 70%,an initiator dosage of 0.15 g,and a crosslinking agent dosage of 0.15 g.The hydrogel preparation conditions were optimized using the response surface method,and the interactions between the different reaction conditions were analysed to obtain the best preparation conditions.X-ray diffraction results showed that hydrogels were amorphous in structure.Scanning electron microscopy images showed that the SiO_(2)particles from the sludge acted as crosslinking points between different layers of hydrogel chains.The crosslinking polymerisation and crosslinking agent worked together to form hydrogels with an inorganic-organic double network structure,and this structure was highly stretchable,resulting in hydrogels with good swelling properties. 展开更多
关键词 OXIDANT municipal sludge carbon component swelling property HYDROGEL
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Study and Comparison of Swelling and Compressibility Characteristics of Crumb Marl, Flaky Marl with Attapulgite and Sandy Clay from the Diamniadio Urban Pole at the Oedometer
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作者 Khadim Faye Fatou Samb +1 位作者 Yves Berthaud Pape Sanou Faye 《Geomaterials》 2023年第3期61-70,共10页
In Senegal, the Diamniadio, Sebikhotane and Bargny sector contains clay soils that are problematic for construction. In order to have more information on the behavior of the clay soils of Diamniadio, free swelling tes... In Senegal, the Diamniadio, Sebikhotane and Bargny sector contains clay soils that are problematic for construction. In order to have more information on the behavior of the clay soils of Diamniadio, free swelling tests followed by load-discharge cycles were carried out according to standard NF P 94-090-1. These tests were carried out using an Oedometric device on the three samples from the study site (sandy clays with calcareous concretion, marls with crumbs and laminated marls with attapulgite) to apprehend their swelling aspects in saturated conditions. For the free swelling test, a determination of the different swelling phases will be carried out followed by a comparison of the rate of evolution of the phases for the three samples from the site. In the same vein, the compressibility characteristics of the samples will also be provided from load-unload Oedometric tests. Thereafter, we proceed to a comparison of the void index at the initial state of the samples after two charge-discharge cycles and the influence of the cycles on the reorganization of the internal structure of the samples. These studies will provide more information on the swelling behavior of Diamniadio soils in the presence of water. 展开更多
关键词 Clay swelling Expansive Soil Evolution of The swelling Compressibility Coefficient Charge-Discharge Cycle
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膨胀土微结构对膨胀行为的影响
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作者 刘正楠 张锐 +2 位作者 唐德力 刘昭京 周豫 《土木与环境工程学报(中英文)》 CSCD 北大核心 2024年第2期60-69,共10页
评估膨胀土的膨胀行为对于膨胀土地区的结构设计十分重要。因降雨入渗,膨胀土在垂直方向和水平方向均产生膨胀变形,当膨胀变形受抑制时将产生膨胀压力,影响其周围结构的稳定性。为揭示膨胀土在增湿膨胀过程中出现各向异性的原因,从微观... 评估膨胀土的膨胀行为对于膨胀土地区的结构设计十分重要。因降雨入渗,膨胀土在垂直方向和水平方向均产生膨胀变形,当膨胀变形受抑制时将产生膨胀压力,影响其周围结构的稳定性。为揭示膨胀土在增湿膨胀过程中出现各向异性的原因,从微观角度出发,通过电镜扫描(SEM)对百色中膨胀土和枝江弱膨胀土的微观结构进行观察,并通过图像处理技术统计分析膨胀土内黏土矿物颗粒的层状排列。通过研发的二维膨胀仪和改进的试件制备方法,从宏观角度测得了侧限条件下的两向膨胀规律。研究结果表明,膨胀土的微观结构呈片状且面-面相叠;当膨胀土处于天然松散状态时,其内部的黏土矿物颗粒随机定向排列且集聚;压实后,因受各向不均等应力作用,黏土矿物颗粒开始趋向于水平层状排列;干密度越大,土样越密实,其水平层状排列越显著。侧限条件下,两向的膨胀规律表现出显著的差异,干密度越大,膨胀性越强,这种差异就越明显。然而,对黏土矿物颗粒来说,其膨胀的方向垂直于其长轴,高度的水平定向是造成膨胀土在宏观上表现出膨胀各向异性的原因,这种两向的膨胀差异受到干密度和膨胀性的影响,难以做出预测,建议在工程实践中实测两向的膨胀规律。 展开更多
关键词 膨胀土 膨胀各向异性 微观结构 电镜扫描 膨胀试验
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炼焦煤热解过程中膨胀压力的形成机制及对焦炭质量的影响
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作者 王帅 周文艳 +3 位作者 高亚芳 申岩峰 王美君 常丽萍 《煤炭转化》 CAS CSCD 北大核心 2024年第2期30-43,共14页
在工业室式炼焦过程中,膨胀压力过高会造成焦炉炉墙损坏及推焦困难,膨胀压力过低会影响焦炭产品质量。现行焦化工艺通过调节入炉煤挥发分控制膨胀压力,缺乏对炼焦煤膨胀压力形成机制的本质认识,可能导致焦炉运行不稳定、焦炭质量波动大... 在工业室式炼焦过程中,膨胀压力过高会造成焦炉炉墙损坏及推焦困难,膨胀压力过低会影响焦炭产品质量。现行焦化工艺通过调节入炉煤挥发分控制膨胀压力,缺乏对炼焦煤膨胀压力形成机制的本质认识,可能导致焦炉运行不稳定、焦炭质量波动大等问题。基于此,通过分析炼焦煤结构特性,从分子水平探究了膨胀压力的形成及演变,并揭示了炼焦煤膨胀性与焦炭质量的本质联系。利用核磁共振碳谱(^(13)C NMR)分析了五种不同煤阶的炼焦煤(Q1,JA1,F1,J1和S1)的化学结构。通过热重分析(TGA)、小型热解实验等方法以及基式流动度测定仪、奥亚膨胀仪、透气性在线检测装置及膨胀压力和膨胀位移检测装置等仪器探究了单种煤热解过程中煤基体分解行为、流动特性和膨胀特性的演化机制。结果表明:热解气体CO,CO_(2),CH4的释放和低透气性带的形成影响了膨胀压力的产生,适宜的膨胀压力可提高焦炭质量;300℃~450℃是煤产生膨胀压力的温区,与煤中f_(al)^(O1),f_(al)^(O2)和f_(al)^(1)~f_(al)^(5)结构的分解有关;膨胀压力过高(120 kPa~180 kPa)的煤,形成的焦炭孔隙多、真密度小,质量差;膨胀压力适中(90 kPa~120 kPa)的煤,形成的焦炭质量较好。 展开更多
关键词 煤化学结构 流动特性 膨胀特性 演化机制 焦炭质量
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基于DEM-FDM耦合的过渡段膨胀诱发钢轨上拱研究
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作者 汪优 高天涯 +4 位作者 闫斌 王瑞 陈子娟 张文旭 程建军 《铁道工程学报》 EI CSCD 北大核心 2024年第1期7-12,共6页
研究目的:为分析涵洞过渡段地基膨胀引起的钢轨上拱响应,基于现场测试、室内膨胀试验数据,开展DEM-FDM耦合数值模拟,分析某涵洞附近路基土在膨胀范围为16 m,膨胀中心距离涵洞中心分别为0 m、5 m、10 m这三种工况下,不同膨胀率时基床填... 研究目的:为分析涵洞过渡段地基膨胀引起的钢轨上拱响应,基于现场测试、室内膨胀试验数据,开展DEM-FDM耦合数值模拟,分析某涵洞附近路基土在膨胀范围为16 m,膨胀中心距离涵洞中心分别为0 m、5 m、10 m这三种工况下,不同膨胀率时基床填料的运动规律及钢轨的上拱响应。研究结论:(1)涵洞对于钢轨上拱位移的传递存在阻断作用,但会增大钢轨上拱的峰值,原位膨胀率下工况二的钢轨上拱峰值达到46 mm,当路基膨胀率为0.3%时钢轨上拱位移量达到无砟轨道钢轨可调节临界值(4mm);(2)过渡段钢轨上拱处同时产生轴向应力集中,其中原位膨胀率下工况二轴向应力峰值达到14.4 MPa;(3)对于膨胀区域位于涵洞下方的工况,钢轨轴向应力呈现出来的分布规律为钢轨上拱拱顶处为主拉应力状态,拱脚处为主压应力状态,因此一共包括三个压应力峰值点以及两个拉应力峰值点;(4)本文研究可为高铁涵洞过渡段路基膨胀病害解决方案的确定提供理论依据。 展开更多
关键词 过渡段 路基膨胀 无砟轨道 钢轨上拱 有限差分 离散元
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雷火灸联合护理干预促进膝关节周围骨折术后功能恢复效果观察
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作者 李五妹 刘兰英 李周 《中西医结合护理》 2024年第1期50-55,共6页
目的观察雷火灸联合护理干预促进膝关节周围骨折术后关节功能恢复的效果。方法采用随机数字表法将50例患者分为对照组和观察组。对照组给予常规治疗和护理,观察组在对照组基础上增加雷火灸治疗。比较两组干预效果。结果随访共得到48例... 目的观察雷火灸联合护理干预促进膝关节周围骨折术后关节功能恢复的效果。方法采用随机数字表法将50例患者分为对照组和观察组。对照组给予常规治疗和护理,观察组在对照组基础上增加雷火灸治疗。比较两组干预效果。结果随访共得到48例患者完整结果,对照组及观察组各24例。治疗3 d、7 d后,观察组患者患侧上、下周径均小于对照组,差异有统计学意义(P<0.05)。治疗3 d、7 d后,观察组患者患侧VAS评分低于对照组,差异有统计学意义(P<0.05)。治疗1周、3周、5周后,观察组患者患侧膝HSS评分均较治疗前提高(P<0.05);治疗3周、5周后,观察组患者患侧膝HSS评分高于对照组(P<0.05)。治疗7 d后,观察组患者患侧膝关节活动度大于对照组,差异有统计学意义(P<0.05)。结论膝关节周围骨折术后护理配合实施雷火灸治疗,能有效减轻患肢肿胀、疼痛,促进康复,改善膝关节活动度及功能,有利于提高临床治疗效果。 展开更多
关键词 雷火灸 膝关节周围骨折 术后康复 中医护理 肿胀 疼痛
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