A numerical method is proposed for the elasto-plasticity and pore-pressure coupled analysis on the pull- out behaviors of a plate anchor. The bounding-surface plasticity （BSP） model combined with Blot＇s consol- ida...A numerical method is proposed for the elasto-plasticity and pore-pressure coupled analysis on the pull- out behaviors of a plate anchor. The bounding-surface plasticity （BSP） model combined with Blot＇s consol- idation theory is employed to simulate the cyclic loading induced elasto-plastic deformation of the soil skeleton and the accompanying generation/dissipation of the excess pore water pressure. The suction force generated around the anchor due to the cyclic variation of the pore water pressure has much effect on the pullout capacity of the plate anchor. The calculated pullout capacity with the proposed method （i.e., the coupled analysis） gets lower than that with the conventional total stress analysis for the case of long-term sustained loading, but slightly higher for the case of short-term monotonic loading. The cyclic loading induced accumulation of pore water pressure may result in an obvious decrease of the stiffness of the soil-Plate anchor svstem.展开更多
Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio w...Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.展开更多
Long piles of the ocean oil platform are usually manufactured as the integration of several segments, which have to be assembled one by one during installation. During pile driving, excessive pore pressure will build ...Long piles of the ocean oil platform are usually manufactured as the integration of several segments, which have to be assembled one by one during installation. During pile driving, excessive pore pressure will build up in such a high level that hydraulic fracturing in the soil round the pile may take place, which will cause the soil to consolidate much faster during pile extension period. Consequently, after pile extension, the soil strength will recover to some extent and the driving resistance will increase considerably, which makes restarting driving the pile very difficult and even causes refusal. A finite element （FE） analysis procedure is presented for judging the risk of refusal by estimating the blow counts after pile extension, in which the regain of soil strength is considered. A case analysis in Bohai Gulf is performed using the proposed orocedure to exolain the nile refusal phenomenon.展开更多
To explore the feasibility of recycling industrial waste as building materials,this study developed an environmentally friendly,low-carbon pervious concrete(PC).This study used coal gangue micro-powder(CGMP)and ground...To explore the feasibility of recycling industrial waste as building materials,this study developed an environmentally friendly,low-carbon pervious concrete(PC).This study used coal gangue micro-powder(CGMP)and ground granulated blast furnace slag(GGBS)as supplementary cementitious materials to partially replace cement.Coal gangue sand(CGS)was used as fine aggregate,while municipal solid waste incineration slag(MSWI)and natural crushed stone aggregate(NCA)were used as coarse aggregates.The study investigated the effects of single-doping of CGMP(proportions:10%,20%,30%,40%)and composite doping of CGMP and GGBS(total admixture amount of 30%with CGMP-to-GGBS ratios of 1:1,1:2,and 2:1)on the compressive,splitting tensile,and flexural strength,permeability,pore structure,and frost resistance of PC.Additionally,carbon dioxide(CO_(2))emissions and cost analyses were conducted.The results showed that single-doping of CGMP led to a decline in the mechanical properties and a deterioration of the permeability of PC.When the two materials were co-doped at a ratio of 1:2,the specimens exhibited a synergistic improvement in mechanical properties,although the permeability decreased.The 7-day and 28-day compressive strengths were 19.8 MPa and 24.6 MPa,respectively,and the permeability coefficient was 1.9 mm/s.In terms of freeze–thaw resistance,increasing the proportion of GGBS in the composite doping of mineral admixtures could improve frost resistance.Furthermore,the loss rate of compressive strength proved to be the most sensitive indicator of freeze–thaw effects,making it the most suitable parameter for durability assessment.In terms of carbon efficiency,life cycle assessment(LCA)indicates that compared with normal concrete pavement(NCP),the life-cycle carbon emissions per cubic meter of PC pavement prepared by the G10S20 scheme(a composite doping scheme with a total admixture content of 30%,including 10%CGMP and 20%GGBS)are reduced by 14.28%(from 410.148 kg CO_(2)e to 351.577 kg CO_(2)e),and by 14.80%compared with normal pervious concrete pavement(NPCP).In addition,cost analysis confirms that the construction cost of G10S20 pavement is 22.38%lower than that of NCP and 14.46%lower than that of NPCP.This material can effectively alleviate urban waterlogging,mitigate the heat island effect,and has both low-carbon and economic advantages when applied in scenarios such as urban roads,squares,and park ground paving.It thus provides practical evidence for the promotion of sustainable building materials.展开更多
基金supported by the National Natural Science Foundation of China(51309213)the 973 program of China (2014CB046200)
文摘A numerical method is proposed for the elasto-plasticity and pore-pressure coupled analysis on the pull- out behaviors of a plate anchor. The bounding-surface plasticity （BSP） model combined with Blot＇s consol- idation theory is employed to simulate the cyclic loading induced elasto-plastic deformation of the soil skeleton and the accompanying generation/dissipation of the excess pore water pressure. The suction force generated around the anchor due to the cyclic variation of the pore water pressure has much effect on the pullout capacity of the plate anchor. The calculated pullout capacity with the proposed method （i.e., the coupled analysis） gets lower than that with the conventional total stress analysis for the case of long-term sustained loading, but slightly higher for the case of short-term monotonic loading. The cyclic loading induced accumulation of pore water pressure may result in an obvious decrease of the stiffness of the soil-Plate anchor svstem.
基金financial support from the National Natural Science Youth Foundation of China(No.32002443)the Natural Science Foundation of Shandong Province(No.ZR2021QD 149)。
文摘Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.
基金supported by the National Natural Science Foundation of China(51322904 and 51279127)the Program for New Century Excellent Talents in University(HCET-11-0370)
文摘Long piles of the ocean oil platform are usually manufactured as the integration of several segments, which have to be assembled one by one during installation. During pile driving, excessive pore pressure will build up in such a high level that hydraulic fracturing in the soil round the pile may take place, which will cause the soil to consolidate much faster during pile extension period. Consequently, after pile extension, the soil strength will recover to some extent and the driving resistance will increase considerably, which makes restarting driving the pile very difficult and even causes refusal. A finite element （FE） analysis procedure is presented for judging the risk of refusal by estimating the blow counts after pile extension, in which the regain of soil strength is considered. A case analysis in Bohai Gulf is performed using the proposed orocedure to exolain the nile refusal phenomenon.
基金First Class Discipline Construction in Ningxia Colleges and Universities(discipline of water conservancy engineering)(NXYLXK 2021A03).
文摘To explore the feasibility of recycling industrial waste as building materials,this study developed an environmentally friendly,low-carbon pervious concrete(PC).This study used coal gangue micro-powder(CGMP)and ground granulated blast furnace slag(GGBS)as supplementary cementitious materials to partially replace cement.Coal gangue sand(CGS)was used as fine aggregate,while municipal solid waste incineration slag(MSWI)and natural crushed stone aggregate(NCA)were used as coarse aggregates.The study investigated the effects of single-doping of CGMP(proportions:10%,20%,30%,40%)and composite doping of CGMP and GGBS(total admixture amount of 30%with CGMP-to-GGBS ratios of 1:1,1:2,and 2:1)on the compressive,splitting tensile,and flexural strength,permeability,pore structure,and frost resistance of PC.Additionally,carbon dioxide(CO_(2))emissions and cost analyses were conducted.The results showed that single-doping of CGMP led to a decline in the mechanical properties and a deterioration of the permeability of PC.When the two materials were co-doped at a ratio of 1:2,the specimens exhibited a synergistic improvement in mechanical properties,although the permeability decreased.The 7-day and 28-day compressive strengths were 19.8 MPa and 24.6 MPa,respectively,and the permeability coefficient was 1.9 mm/s.In terms of freeze–thaw resistance,increasing the proportion of GGBS in the composite doping of mineral admixtures could improve frost resistance.Furthermore,the loss rate of compressive strength proved to be the most sensitive indicator of freeze–thaw effects,making it the most suitable parameter for durability assessment.In terms of carbon efficiency,life cycle assessment(LCA)indicates that compared with normal concrete pavement(NCP),the life-cycle carbon emissions per cubic meter of PC pavement prepared by the G10S20 scheme(a composite doping scheme with a total admixture content of 30%,including 10%CGMP and 20%GGBS)are reduced by 14.28%(from 410.148 kg CO_(2)e to 351.577 kg CO_(2)e),and by 14.80%compared with normal pervious concrete pavement(NPCP).In addition,cost analysis confirms that the construction cost of G10S20 pavement is 22.38%lower than that of NCP and 14.46%lower than that of NPCP.This material can effectively alleviate urban waterlogging,mitigate the heat island effect,and has both low-carbon and economic advantages when applied in scenarios such as urban roads,squares,and park ground paving.It thus provides practical evidence for the promotion of sustainable building materials.
