Wicking geotextile(WG)is considered as a possible countermeasure to reduce water content in unsaturated soil.In this research,rainfall tests were carried out to verify the drainage performance of WG.And capillary rise...Wicking geotextile(WG)is considered as a possible countermeasure to reduce water content in unsaturated soil.In this research,rainfall tests were carried out to verify the drainage performance of WG.And capillary rise tests were conducted to study the effect of WG on the prevention of capillary rise.Test results indicated that WG with good drainage performance could drain gravitational and capillary water out of kaolinite soil.For kaolinite soil column with water content of 12%and compaction degree of 90%,the whole process of capillary rise in soil column with a layer of WG was a typical two-stage mode,and the maximum capillary height was about 380 mm,which provided that the WG could work as a barrier to prevent capillary rise effectively.In addition,the total vertical influential regions of WG in kaolinite soil above and below the WG layer were 400 and 100 mm,respectively.展开更多
This study investigates the effect of various tread designs to enhance grip on both dry and wet friction,aiming to reduce slip and fall accidents,especially in slipprone workplaces and among the elderly.The research i...This study investigates the effect of various tread designs to enhance grip on both dry and wet friction,aiming to reduce slip and fall accidents,especially in slipprone workplaces and among the elderly.The research involves analyzing frictional performance and deformation characteristics through dry and wet friction testing.Computeraided design(CAD)software was used to create digital models of various tread patterns,and two different additive manufacturing(AM)techniques,fused filament fabrication(FFF)and stereolithography(SLA)printing,were used for three-dimensional(3D)print block samples with tread patterns,and the materials used were thermoplastic rubber(TPR)filament and photocurable elastomeric resin.A specialized friction testing machine was used to measure the friction force of the treads on a glass surface under dry and wet conditions.A high-speed camera recorded the treads’deformation and water drainage during testing.The results revealed the influence of tread pattern designs with two different rubber-like materials on friction and deformation,as well as performance on various contact surfaces.展开更多
The innovative utilization of Yellow River sediment to reclaim coal-mined subsided lands addresses dual environmental challenges by offering a sustainable remediation technique.However,efficient water drainage constit...The innovative utilization of Yellow River sediment to reclaim coal-mined subsided lands addresses dual environmental challenges by offering a sustainable remediation technique.However,efficient water drainage constitutes a significant hurdle in this context.The strategic placement of nonwoven geotextile at the tail end of the fill sections has ameliorated fine sediment loss and drainage efficacy issues.This study assesses various nonwoven geotextile grades for their effectiveness in moisture expulsion,integrating comprehensive evaluations and simulation tests of pivotal processes.The findings reveal that selected nonwoven geotextiles(N1,N2,T1,T2,T3,T4)demonstrate appropriate apparent opening size(AOS)and permeability,coupled with clogging resistance,aligning with theoretical criteria for soil conservation,water permeation,and blockage prevention.Crucial to the nonwoven geotextile’s clogging are factors such as apparent opening size(AOS),thickness,permeability,load capacity,gradient ratio(GR),and sediment retention-all requiring meticulous selection for real-world application.The choice of nonwoven geotextile in the drainage of Yellow River sediment reclaimed lands must hinge on a holistic assessment framework,encompassing retention,permeability,anti-clogging attributes,and additional performance metrics,to ensure that the materials fulfill the specific technical standards while remaining cost-effective.This study provides valuable insights into the selection and application of geotextiles in Yellow River sediment-backfilled reclamation drainage projects,contributing to the advancement of mine ecological restoration practices,particularly in the context of Yellow River sediment-backfilled reclamation projects.展开更多
The geological condition of Chinese coal mines are complex and high gassy,which account for ffty percent to seventy percent.Because of the abundant pores and cracks around the drainage drilling hole,the gas concentrat...The geological condition of Chinese coal mines are complex and high gassy,which account for ffty percent to seventy percent.Because of the abundant pores and cracks around the drainage drilling hole,the gas concentration attenuates rapidly,and the effective gas drainage period is short.The traditional sealing materials of yellow mud and cement-sand grout will readily shrink after the drilling hole is sealed,the sealing length is short and the sealing quality is not satisfactory.Currently widely used polyurethane material will shrink when it comes into contact with water,and the price is also very high.In this study,taking cement as a base material,a novel composite sealing material mixed by expansion admixture,additive,and fbrin and coupling agent was developed and the sealing performance and expansion property of the material were also studied and analyzed.The FEI Quanta TM 250 environmental scanning electron microscope was used to investigate the microstructure of material.The results revealed that the new composite sealing material had a desirable expansion performance and a defnite fluidity convenient for grouting.The solidifed material,combining closely with the drilling wall,possessed an adequate strength and was not easy to shrink.Compared to the conventional polyurethane,the gas drainage concentration by drilling sealing exceeded 40 percent,and the sealing capacity improves5 times,the sealing effect increases signifcantly.展开更多
The black soil area in northeast China is greatly affected by hydraulic erosion.To inhibit the development of gully cutting and the secondary erosion on farmland,different size coal gangues and covering soils with cha...The black soil area in northeast China is greatly affected by hydraulic erosion.To inhibit the development of gully cutting and the secondary erosion on farmland,different size coal gangues and covering soils with change thicknesses combinations were selected to fill in-situ gully for hydraulic performance experiment.The hydraulic performance indexes of different combinations of large and small size gangue thicknesses and covering soil thicknesses were analyzed by the extreme learning machine(ELM)and particle swarm optimization(PSO).The results showed that the structure of large and small size coal gangues and surface soil under different thicknesses was affected by hydraulic and gravity.With the change of the thicknesses of coal gangue and covering soil,its effective channel and vertical infiltration process became more and more stable with the increase in drainage time,while the structure of small size coal gangue was the main hydraulic factor in reconstructed soil structure(p=0.016).The overall drainage performance showed a single peak trend,the optimal combination of drainage parameters and structure thickness was relatively concentrated;the drainage time parameters of different composite structures were found to have a certain linear relationship;the Pareto optimum of drainage performance was determined.The optimum thickness was 30-40 cm for large-sized gangue,30-60 cm for small-sized gangue,and 50-70 cm for covering soil,to meet the relatively good drainage performance and to ensure that secondary erosion was reduced,so as to achieve the purpose of controlling the gully.展开更多
基金Projects(41872240,41672280)supported by the National Natural Science Foundation of ChinaProject(2016-1-16-2)supported by Science and Technology Project of Jilin Province Transportation,ChinaProject(SJCX18-0052)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China。
文摘Wicking geotextile(WG)is considered as a possible countermeasure to reduce water content in unsaturated soil.In this research,rainfall tests were carried out to verify the drainage performance of WG.And capillary rise tests were conducted to study the effect of WG on the prevention of capillary rise.Test results indicated that WG with good drainage performance could drain gravitational and capillary water out of kaolinite soil.For kaolinite soil column with water content of 12%and compaction degree of 90%,the whole process of capillary rise in soil column with a layer of WG was a typical two-stage mode,and the maximum capillary height was about 380 mm,which provided that the WG could work as a barrier to prevent capillary rise effectively.In addition,the total vertical influential regions of WG in kaolinite soil above and below the WG layer were 400 and 100 mm,respectively.
文摘This study investigates the effect of various tread designs to enhance grip on both dry and wet friction,aiming to reduce slip and fall accidents,especially in slipprone workplaces and among the elderly.The research involves analyzing frictional performance and deformation characteristics through dry and wet friction testing.Computeraided design(CAD)software was used to create digital models of various tread patterns,and two different additive manufacturing(AM)techniques,fused filament fabrication(FFF)and stereolithography(SLA)printing,were used for three-dimensional(3D)print block samples with tread patterns,and the materials used were thermoplastic rubber(TPR)filament and photocurable elastomeric resin.A specialized friction testing machine was used to measure the friction force of the treads on a glass surface under dry and wet conditions.A high-speed camera recorded the treads’deformation and water drainage during testing.The results revealed the influence of tread pattern designs with two different rubber-like materials on friction and deformation,as well as performance on various contact surfaces.
基金funded by the National Natural Science Foundation of China(Grant No.41771542).
文摘The innovative utilization of Yellow River sediment to reclaim coal-mined subsided lands addresses dual environmental challenges by offering a sustainable remediation technique.However,efficient water drainage constitutes a significant hurdle in this context.The strategic placement of nonwoven geotextile at the tail end of the fill sections has ameliorated fine sediment loss and drainage efficacy issues.This study assesses various nonwoven geotextile grades for their effectiveness in moisture expulsion,integrating comprehensive evaluations and simulation tests of pivotal processes.The findings reveal that selected nonwoven geotextiles(N1,N2,T1,T2,T3,T4)demonstrate appropriate apparent opening size(AOS)and permeability,coupled with clogging resistance,aligning with theoretical criteria for soil conservation,water permeation,and blockage prevention.Crucial to the nonwoven geotextile’s clogging are factors such as apparent opening size(AOS),thickness,permeability,load capacity,gradient ratio(GR),and sediment retention-all requiring meticulous selection for real-world application.The choice of nonwoven geotextile in the drainage of Yellow River sediment reclaimed lands must hinge on a holistic assessment framework,encompassing retention,permeability,anti-clogging attributes,and additional performance metrics,to ensure that the materials fulfill the specific technical standards while remaining cost-effective.This study provides valuable insights into the selection and application of geotextiles in Yellow River sediment-backfilled reclamation drainage projects,contributing to the advancement of mine ecological restoration practices,particularly in the context of Yellow River sediment-backfilled reclamation projects.
基金fnancially supported by the National Natural Science Foundation of China(No.51274195)the Natural Science Foundation of Jiangsu Province(No.BK2012571)+3 种基金the Program for New Century Excellent Talents in University(No.NCET-12-0959)the China Postdoctoral Science Foundation(No.20090450930)the National Basic Research Program of China(No.2011CB201205)Qing Lan Project,and the Youth Foundation of China University of Mining and Technology(No.2007A003)
文摘The geological condition of Chinese coal mines are complex and high gassy,which account for ffty percent to seventy percent.Because of the abundant pores and cracks around the drainage drilling hole,the gas concentration attenuates rapidly,and the effective gas drainage period is short.The traditional sealing materials of yellow mud and cement-sand grout will readily shrink after the drilling hole is sealed,the sealing length is short and the sealing quality is not satisfactory.Currently widely used polyurethane material will shrink when it comes into contact with water,and the price is also very high.In this study,taking cement as a base material,a novel composite sealing material mixed by expansion admixture,additive,and fbrin and coupling agent was developed and the sealing performance and expansion property of the material were also studied and analyzed.The FEI Quanta TM 250 environmental scanning electron microscope was used to investigate the microstructure of material.The results revealed that the new composite sealing material had a desirable expansion performance and a defnite fluidity convenient for grouting.The solidifed material,combining closely with the drilling wall,possessed an adequate strength and was not easy to shrink.Compared to the conventional polyurethane,the gas drainage concentration by drilling sealing exceeded 40 percent,and the sealing capacity improves5 times,the sealing effect increases signifcantly.
基金Supported by the National Key R&D Program of China(Topic 2017YFC0504200)。
文摘The black soil area in northeast China is greatly affected by hydraulic erosion.To inhibit the development of gully cutting and the secondary erosion on farmland,different size coal gangues and covering soils with change thicknesses combinations were selected to fill in-situ gully for hydraulic performance experiment.The hydraulic performance indexes of different combinations of large and small size gangue thicknesses and covering soil thicknesses were analyzed by the extreme learning machine(ELM)and particle swarm optimization(PSO).The results showed that the structure of large and small size coal gangues and surface soil under different thicknesses was affected by hydraulic and gravity.With the change of the thicknesses of coal gangue and covering soil,its effective channel and vertical infiltration process became more and more stable with the increase in drainage time,while the structure of small size coal gangue was the main hydraulic factor in reconstructed soil structure(p=0.016).The overall drainage performance showed a single peak trend,the optimal combination of drainage parameters and structure thickness was relatively concentrated;the drainage time parameters of different composite structures were found to have a certain linear relationship;the Pareto optimum of drainage performance was determined.The optimum thickness was 30-40 cm for large-sized gangue,30-60 cm for small-sized gangue,and 50-70 cm for covering soil,to meet the relatively good drainage performance and to ensure that secondary erosion was reduced,so as to achieve the purpose of controlling the gully.
