Most view articles
2015, 32(3):51-54.
DOI: 10.3969/j.issn.1673-9469.2015.03.012
Abstract:
In order to analyze the law of ultimate bearing capacity of the pile and numerical simulation studies to improve the bearing capacity factors,the finite element analysis software ABAQUS is used by combining with the investigation data of actual project,selected of pile and soil mechanics parameters is selected suitably and numerical simulation of the static load test of single pile is carried out.The simulation results show that through reasonable choice pile of soil mechanics parameters,simulation Q~S curves and filed measured values are well.This indicated that the use of ABAQUS finite element analysis software simulation to pile static load test is feasible.At the same time,it is beneficial to improve the ultimate bearing capacity of single pile through analyzing the effects of different coefficient of friction μ on bearing capacity.Therefore,mainly by the friction of the pile side from the pile top is transferred to the pile end bearing capacity limit friction pile;axial force transmission gradually decreases from top to bottom;changes of soil pile interaction but also to improve the ultimate bearing capacity of pile method.
In order to analyze the law of ultimate bearing capacity of the pile and numerical simulation studies to improve the bearing capacity factors,the finite element analysis software ABAQUS is used by combining with the investigation data of actual project,selected of pile and soil mechanics parameters is selected suitably and numerical simulation of the static load test of single pile is carried out.The simulation results show that through reasonable choice pile of soil mechanics parameters,simulation Q~S curves and filed measured values are well.This indicated that the use of ABAQUS finite element analysis software simulation to pile static load test is feasible.At the same time,it is beneficial to improve the ultimate bearing capacity of single pile through analyzing the effects of different coefficient of friction μ on bearing capacity.Therefore,mainly by the friction of the pile side from the pile top is transferred to the pile end bearing capacity limit friction pile;axial force transmission gradually decreases from top to bottom;changes of soil pile interaction but also to improve the ultimate bearing capacity of pile method.
2010, 27(2):54-59.
Abstract:
The prior 16 kind of PAHs in pollutants controlled by the US EPA have been analyzed with gas chromatography(GC) in the water sample from Dongwushi Reservoir in Handan,and 7 kind of PAHs are detected with a total mass concentration of 7.28μg/L.The high molecular weight PAHs with 4 and 6 benzene rings predominate in PAHs components with 79.6 percent,much more than the low molecular weight components.Among them,benz(a)anthracene accounts for 51.8 percent,benzo(g,h,i)perylene does 15.8 percent,and others else from more to less are phenanthrene,indeno(1,2,3-cd)pyrene,benzo(b)fluoranthene,fluorene and fluoranthene,respectively.Such distribution suggests that PAHs in the Reservoir water derive mainly from pollution of incomplete combustion of coal,and lesser from the drainage of coal mine.The high concentration of total PAHs and members indicates that an evident PAHs pollution has occurred in the water body,and in all probability brings potential ecological risk to the environment,to which the people and local government ought to pay much more attention.
The prior 16 kind of PAHs in pollutants controlled by the US EPA have been analyzed with gas chromatography(GC) in the water sample from Dongwushi Reservoir in Handan,and 7 kind of PAHs are detected with a total mass concentration of 7.28μg/L.The high molecular weight PAHs with 4 and 6 benzene rings predominate in PAHs components with 79.6 percent,much more than the low molecular weight components.Among them,benz(a)anthracene accounts for 51.8 percent,benzo(g,h,i)perylene does 15.8 percent,and others else from more to less are phenanthrene,indeno(1,2,3-cd)pyrene,benzo(b)fluoranthene,fluorene and fluoranthene,respectively.Such distribution suggests that PAHs in the Reservoir water derive mainly from pollution of incomplete combustion of coal,and lesser from the drainage of coal mine.The high concentration of total PAHs and members indicates that an evident PAHs pollution has occurred in the water body,and in all probability brings potential ecological risk to the environment,to which the people and local government ought to pay much more attention.
2008, 25(4):107-109.
Abstract:
An adaptive differential evolution algorithm is presented.It adjusts scale factor adaptively according to the computation process in order to preserve the diversity of population at the initial generation as well as to enhance the global searching ability and to improve local searching capacity and precision of solution finally.Experimental results show that the presented algorithm can avoid premature convergence effectively and enhance the global searching ability.
An adaptive differential evolution algorithm is presented.It adjusts scale factor adaptively according to the computation process in order to preserve the diversity of population at the initial generation as well as to enhance the global searching ability and to improve local searching capacity and precision of solution finally.Experimental results show that the presented algorithm can avoid premature convergence effectively and enhance the global searching ability.
2015, 32(3):78-82.
DOI: 10.3969/j.issn.1673-9469.2015.03.019
Abstract:
Taking Dushu Lake Campus of Soochow University as an example, through the calculation of daylight factor and Ecotect simulation, the indoor light environment analysis were carried out by using the method of investigation, instrument test, Ecotect numerical simulation, statistical analysis and so on. The effects of different materials and lighting form on indoor light environment were studied by according to comparative analysis of data .In order to get the right interior daylight factor, we should choose light-colored walls and the top surface, architects should not add too much decorative lines when we design the facade, window's shape, size, position level should be based on the size of the interior space, the shape and the height.
Taking Dushu Lake Campus of Soochow University as an example, through the calculation of daylight factor and Ecotect simulation, the indoor light environment analysis were carried out by using the method of investigation, instrument test, Ecotect numerical simulation, statistical analysis and so on. The effects of different materials and lighting form on indoor light environment were studied by according to comparative analysis of data .In order to get the right interior daylight factor, we should choose light-colored walls and the top surface, architects should not add too much decorative lines when we design the facade, window's shape, size, position level should be based on the size of the interior space, the shape and the height.
2015, 32(2):31-35.
DOI: 10.3969/j.issn.1673-9469.2015.02.008
Abstract:
Considering the different displacement boundary condition, the model of 2D-FGM plate with temperature independency of material properties was established, and the cooling transient thermal stress field distribution pictures were obtained with the finite element method. Effects on the transient thermal tress of 2D-FGM plate with temperature independency of material properties of during cooling process that the displacement boundary condition made were influential enormously. The thermal stress σx of on the free boundary of the 2D-FGM plate under simple supported and under one end clamped is zero; The thermal stresses accumulation were formed on the middle and lower of the two left and right boundaries of the 2D-FGM plate under two ends clamped, at the same time the shape and values of the thermal stress changed tremendously; To the 2D-FGM plate under clamped all around, the growth rate of the thermal stresses was more obvious than that of the 2D-FGM plate under two ends clamped. The results of this paper provide the foundations of theory calculation for the design and fabrication of the material.
Considering the different displacement boundary condition, the model of 2D-FGM plate with temperature independency of material properties was established, and the cooling transient thermal stress field distribution pictures were obtained with the finite element method. Effects on the transient thermal tress of 2D-FGM plate with temperature independency of material properties of during cooling process that the displacement boundary condition made were influential enormously. The thermal stress σx of on the free boundary of the 2D-FGM plate under simple supported and under one end clamped is zero; The thermal stresses accumulation were formed on the middle and lower of the two left and right boundaries of the 2D-FGM plate under two ends clamped, at the same time the shape and values of the thermal stress changed tremendously; To the 2D-FGM plate under clamped all around, the growth rate of the thermal stresses was more obvious than that of the 2D-FGM plate under two ends clamped. The results of this paper provide the foundations of theory calculation for the design and fabrication of the material.
2016, 33(2):25-29.
DOI: 10.3969/j.issn.1673-9469.2016.02.006
Abstract:
To obtain the ultimate bearing capacity of suction caisson under inclined load in saturated sand, the interaction failure envelop was used to analyze the bearing behavior of suction caisson. Based on the 25 model tests in sand, the ultimate capacity of suction caisson under different loading conditions was summarized. The lateral capacity factor and the vertical capacity factor were assumed to analyze the influences of the loading position, loading inclination angle on the ultimate bearing capacity. It was found that there is a power function relationship between the normalized ultimate horizontal bearing capacity and the normalized ultimate vertical bearing capacity. Thus, the ultimate inclined bearing capacity can be obtained with the loading angle between the horizontal capacity and the vertical capacity.
To obtain the ultimate bearing capacity of suction caisson under inclined load in saturated sand, the interaction failure envelop was used to analyze the bearing behavior of suction caisson. Based on the 25 model tests in sand, the ultimate capacity of suction caisson under different loading conditions was summarized. The lateral capacity factor and the vertical capacity factor were assumed to analyze the influences of the loading position, loading inclination angle on the ultimate bearing capacity. It was found that there is a power function relationship between the normalized ultimate horizontal bearing capacity and the normalized ultimate vertical bearing capacity. Thus, the ultimate inclined bearing capacity can be obtained with the loading angle between the horizontal capacity and the vertical capacity.
2014, 31(1):94-97.
Abstract:
For the influence of vibration and noise problem of switched reluctance motors,the paper applies maxwell stress method,considering the magnetic saturation of ferromagnetic materials and the edge effect of flux,analyzing and calculating the flux density of air gap and electromagnetic force.The nonlinear mathematical model of magnetism and solid coupling of the stator system is set up.This model conforms to the actual operation characteristics of switched reluctance motor,provides the theoretical reference for optimizing design of the motor.With a prototype as an example,results show that the model of the 2D finite element analysis of the results compared to verify the correctness of the mathematical model.
For the influence of vibration and noise problem of switched reluctance motors,the paper applies maxwell stress method,considering the magnetic saturation of ferromagnetic materials and the edge effect of flux,analyzing and calculating the flux density of air gap and electromagnetic force.The nonlinear mathematical model of magnetism and solid coupling of the stator system is set up.This model conforms to the actual operation characteristics of switched reluctance motor,provides the theoretical reference for optimizing design of the motor.With a prototype as an example,results show that the model of the 2D finite element analysis of the results compared to verify the correctness of the mathematical model.
2020, 37(1):75-83.
DOI: 10.3969/j.issn.1673-9469.2020.01.013
Abstract:
Taking the runoff data of 23 meteorological stations in the Huaihe River Basin(HRB) from 1951 to 2016 and the runoff data of the Bengbu hydrological station as the research objects, linear quasi-legal, sliding average and non-parametric MK test were used to analyze the characteristics of precipitation and drought in the HRB.The correlation between precipitation, drought and runoff and long-range memory was analyzed with the combination of R/ S analysis, Pearson and Spearman correlation coefficient. The results show that except for continuous wet days, the extreme hydrological index of HRB showed a significant increasing trend, and the abrupt years were concentrated in the 1950s and early 1960s. In the past 70 years, the annual drought frequency reached 21.2%, and the proportion of light drought was the highest. From the annual and seasonal scales, the winter drought is the most severe, and the annual and seasonal drought show a decreasing trend. There is a moderate correlation between precipitation and runoff over a maximum of 30 and 15 days. The precipitation and runoff in flood season and non-flood season are moderate and weak respectively. In the next 4 to 11 years, the maximum 30-day precipitation and runoff, the precipitation and runoff in the flood season and the non-flood season willnot show significant growth trends.
Taking the runoff data of 23 meteorological stations in the Huaihe River Basin(HRB) from 1951 to 2016 and the runoff data of the Bengbu hydrological station as the research objects, linear quasi-legal, sliding average and non-parametric MK test were used to analyze the characteristics of precipitation and drought in the HRB.The correlation between precipitation, drought and runoff and long-range memory was analyzed with the combination of R/ S analysis, Pearson and Spearman correlation coefficient. The results show that except for continuous wet days, the extreme hydrological index of HRB showed a significant increasing trend, and the abrupt years were concentrated in the 1950s and early 1960s. In the past 70 years, the annual drought frequency reached 21.2%, and the proportion of light drought was the highest. From the annual and seasonal scales, the winter drought is the most severe, and the annual and seasonal drought show a decreasing trend. There is a moderate correlation between precipitation and runoff over a maximum of 30 and 15 days. The precipitation and runoff in flood season and non-flood season are moderate and weak respectively. In the next 4 to 11 years, the maximum 30-day precipitation and runoff, the precipitation and runoff in the flood season and the non-flood season willnot show significant growth trends.
2014, 31(1):1-5.
Abstract:
Early age cracking has been an ever-present problem during the application of recycling coarse aggregate concrete.Influences of recycling coarse aggregate size( 5 ~ 15mm,15 ~ 25mm and 25 ~ 31.5mm) on early age( age: 0 ~ 24h) cracking tendency of recycling coarse aggregate concrete( RC) and recycling coarse aggregate concrete with fly ash( FRC) were studied based on slab test method.The results of the early age cracking indexes and cracking processes indicate that the large aggregate size( 25 ~ 31.5mm) corresponds to the decrease of cracking damage for recycling coarse aggregate concrete targets,the slab test samples with 15-25mm of recycling coarse aggregate size has the optimum efficiency in terms of anti-cracking ability when comparing to the other two kinds of FRC samples for RC samples with 15% fly ash.The experimental result in this paper is very beneficial to the optimization and design of recycling coarse aggregate concrete on anti-cracking mix proportions.
Early age cracking has been an ever-present problem during the application of recycling coarse aggregate concrete.Influences of recycling coarse aggregate size( 5 ~ 15mm,15 ~ 25mm and 25 ~ 31.5mm) on early age( age: 0 ~ 24h) cracking tendency of recycling coarse aggregate concrete( RC) and recycling coarse aggregate concrete with fly ash( FRC) were studied based on slab test method.The results of the early age cracking indexes and cracking processes indicate that the large aggregate size( 25 ~ 31.5mm) corresponds to the decrease of cracking damage for recycling coarse aggregate concrete targets,the slab test samples with 15-25mm of recycling coarse aggregate size has the optimum efficiency in terms of anti-cracking ability when comparing to the other two kinds of FRC samples for RC samples with 15% fly ash.The experimental result in this paper is very beneficial to the optimization and design of recycling coarse aggregate concrete on anti-cracking mix proportions.
2017, 34(2):56-61.
DOI: 10.3969/j.issn.1673-9469.2017.02.011
Abstract:
The traditional linear elastic model cannot simulate the nonlinear seismic response analysis of RCC gravity dam in strong seismic regions．This paper analyzes? the seismic damage characteristics of Ludila RCC dam, when dam and foundation material nonlinearity? are considered at the same time. The main conclusions are as follows: When the foundation rock mass and the dam use the nonlinear materials, the foundation near dam toe is damaged, and with the continuous ground motion, the damage cracks extend gradually to the depth of the foundation. Thus, the stress redistribution of dam body and the stress concentration release at the juncture of dam foundation, which will not cause the earthquake damage at the dam foundation junction. Therefore the earthquake damage area and damage degree of the dam are reduced, which makes the dam more partial safety. The result will be more close to the actual, which has certain reference significance to the guiding project.
The traditional linear elastic model cannot simulate the nonlinear seismic response analysis of RCC gravity dam in strong seismic regions．This paper analyzes? the seismic damage characteristics of Ludila RCC dam, when dam and foundation material nonlinearity? are considered at the same time. The main conclusions are as follows: When the foundation rock mass and the dam use the nonlinear materials, the foundation near dam toe is damaged, and with the continuous ground motion, the damage cracks extend gradually to the depth of the foundation. Thus, the stress redistribution of dam body and the stress concentration release at the juncture of dam foundation, which will not cause the earthquake damage at the dam foundation junction. Therefore the earthquake damage area and damage degree of the dam are reduced, which makes the dam more partial safety. The result will be more close to the actual, which has certain reference significance to the guiding project.
2017, 34(2):30-36.
DOI: 10.3969/j.issn.1673-9469.2017.02.007
Abstract:
The mesostructure of soft soil has important influence on the consolidation process，it is of great guiding significance to consider soft soil structure from meso level and reveal the law of consolidation in a large area of reclamation project. In this paper, we establish the soil mesoscale model based on the discrete element method, match mesoscale parameters of the model according to the laboratory test, analyze the distribution of the seepage field in the soil body with COMSOL, realize to solve the consolidation problem of soft soil with PFC-COMSOL, and compare the analysis scheme with the laboratory test. Research results show that simulating flocculation soft soil with poly grain can truly react mesostructure characteristics of soft soil; Creep can influence the decrement in the process of consolidation of soft soil, creep should be considered in calculating the amount of soft soil compression; Uneven compression appears firstly in the process of consolidation of soft soil, after the excess pore pressure is dissipated completely, the soil recovers uniformity.
The mesostructure of soft soil has important influence on the consolidation process，it is of great guiding significance to consider soft soil structure from meso level and reveal the law of consolidation in a large area of reclamation project. In this paper, we establish the soil mesoscale model based on the discrete element method, match mesoscale parameters of the model according to the laboratory test, analyze the distribution of the seepage field in the soil body with COMSOL, realize to solve the consolidation problem of soft soil with PFC-COMSOL, and compare the analysis scheme with the laboratory test. Research results show that simulating flocculation soft soil with poly grain can truly react mesostructure characteristics of soft soil; Creep can influence the decrement in the process of consolidation of soft soil, creep should be considered in calculating the amount of soft soil compression; Uneven compression appears firstly in the process of consolidation of soft soil, after the excess pore pressure is dissipated completely, the soil recovers uniformity.
15 Parallel optimization of median fltering algorithm based on the combination of MATLAB and OpenACC
2019, 36(2):101-104.
DOI: 10.3969/j.issn.1673-9469.2019.02.023
Abstract:
In this paper, a parallel algorithm combining MATLAB and OpenACC is proposed for the complex programming problems of current CUDA-based median filtering parallel acceleration algorithm and the cumbersome implementation of image data extraction and display. The algorithm uses MATLAB to extract the image and converts it into an array file. Then it uses the OpenACC language to convert the serial code to the parallel code and processes the array file converted by MATLAB. Finally, the filtered data is displayed as an image through MATLAB. The acceleration experiment of the median filtering algorithm is carried out by simulation experiments. The experimental results show that the proposed algorithm accelerates the algorithm faster than the serial program in the case of greatly reducing the amount of code conversion workload. And it is equivalent to the effect of CUDA acceleration.
In this paper, a parallel algorithm combining MATLAB and OpenACC is proposed for the complex programming problems of current CUDA-based median filtering parallel acceleration algorithm and the cumbersome implementation of image data extraction and display. The algorithm uses MATLAB to extract the image and converts it into an array file. Then it uses the OpenACC language to convert the serial code to the parallel code and processes the array file converted by MATLAB. Finally, the filtered data is displayed as an image through MATLAB. The acceleration experiment of the median filtering algorithm is carried out by simulation experiments. The experimental results show that the proposed algorithm accelerates the algorithm faster than the serial program in the case of greatly reducing the amount of code conversion workload. And it is equivalent to the effect of CUDA acceleration.
2020, 37(1):30-34.
DOI: 10.3969/j.issn.1673-9469.2020.01.006
Abstract:
Based on the results of the rheological test of monzogranites, the Biot coefficient was determined by cross-plotting method, the creep model based on permeation pressure damage was established on the basis of the generalized Bingham model, the creep parameters were determined by fitting the rock creep test data, and the parameters of the creep damage model were obtained. The creep constitutive equation of the model was deduced, and the data of the rock creep test were fitted with this model.The fitting results show that the model can not only describe the the decay creep and steady-state creep stage, but also describe the accelerated creep stage of the rock, thus proving the feasibility and rationality of the model.
Based on the results of the rheological test of monzogranites, the Biot coefficient was determined by cross-plotting method, the creep model based on permeation pressure damage was established on the basis of the generalized Bingham model, the creep parameters were determined by fitting the rock creep test data, and the parameters of the creep damage model were obtained. The creep constitutive equation of the model was deduced, and the data of the rock creep test were fitted with this model.The fitting results show that the model can not only describe the the decay creep and steady-state creep stage, but also describe the accelerated creep stage of the rock, thus proving the feasibility and rationality of the model.
2013, 30(4):50-53.
DOI: 10.3969/j.jssn.1673-9469.2013.04.013
Abstract:
Based on the soft soil foundation of Tianjin Binhai New Area,the change of pile group effect coefficient in different pile length,pile diameter,pile spacing and different number of pile were analyzed by using the finite element software MIDAS. The result shows that the pile group effect coefficient decreases as the increase of the pile length,pile diameter and pile number. The pile spacing has little effect on the pile group effect coefficient. The load ratio shared by the soil under the cushion cap increases as the pile spacing,the pile diameter decreases and as the pile length,pile number increases.
Based on the soft soil foundation of Tianjin Binhai New Area,the change of pile group effect coefficient in different pile length,pile diameter,pile spacing and different number of pile were analyzed by using the finite element software MIDAS. The result shows that the pile group effect coefficient decreases as the increase of the pile length,pile diameter and pile number. The pile spacing has little effect on the pile group effect coefficient. The load ratio shared by the soil under the cushion cap increases as the pile spacing,the pile diameter decreases and as the pile length,pile number increases.
2008, 25(3):101-105,100.
Abstract:
The quantities of bacterioplankton and Chl-a were invested in Bohai Bay from May 2005 to October 2005.The results showed that the correlativity between bacterial abundance and Chl-a's concentration was high in October(r=0.845,p0.01) in surface layer water of Bohai Bay.The percentage of marine bacterial biomass was 0.355%～56.25% during the primary productivity of phytoplankton;The spatial change of BB/PB was higher in offshore than inshore.Exogenous organic matter was an important factor in controlling the distribution of bacterioplankton in August,but it was primary production in October.
The quantities of bacterioplankton and Chl-a were invested in Bohai Bay from May 2005 to October 2005.The results showed that the correlativity between bacterial abundance and Chl-a's concentration was high in October(r=0.845,p0.01) in surface layer water of Bohai Bay.The percentage of marine bacterial biomass was 0.355%～56.25% during the primary productivity of phytoplankton;The spatial change of BB/PB was higher in offshore than inshore.Exogenous organic matter was an important factor in controlling the distribution of bacterioplankton in August,but it was primary production in October.
2015, 32(1):58-61.
DOI: 10.3969/j.issn.1673－9469.2015.01.016
Abstract:
The leaching condition of Li from fly ash has been studied in this paper, which includes analyzing the influence of leaching rate of lithium from the size of baked material particle, the concentration of leaching liquid, the temperature in the leaching process, the dosage of the leaching liquid. The result indicates that the leaching rate of lithium can reach 70% in the following conditions: the baked material of fly ash is grinded into fine particle first and then continue to be grinded into paste with water before leaching the paste with solution of 5% sodium carbonate (fly ash: solution of sodium carbonate = 1: 100) and heat it 2h on 140 ℃. At last, leachate will be obtained after filtering.
The leaching condition of Li from fly ash has been studied in this paper, which includes analyzing the influence of leaching rate of lithium from the size of baked material particle, the concentration of leaching liquid, the temperature in the leaching process, the dosage of the leaching liquid. The result indicates that the leaching rate of lithium can reach 70% in the following conditions: the baked material of fly ash is grinded into fine particle first and then continue to be grinded into paste with water before leaching the paste with solution of 5% sodium carbonate (fly ash: solution of sodium carbonate = 1: 100) and heat it 2h on 140 ℃. At last, leachate will be obtained after filtering.
2015, 32(2):105-108.
DOI: 10.3969/j.issn.1673-9469.2015.02.026
Abstract:
Focusing on the current situation of security risk management in building construction project, security risk evaluation indexes system is established through comprehensive consider six major factors as follow personnel, materials, mechanical equipment, environment and management. The weight of each index can be gotten by information entropy, applying extension theory to evaluate risk and the level of risk in building construction project is obtained. Finally, an example is provided to verify reliability of the method, giving some reference for security risk evaluation of building construction project.
Focusing on the current situation of security risk management in building construction project, security risk evaluation indexes system is established through comprehensive consider six major factors as follow personnel, materials, mechanical equipment, environment and management. The weight of each index can be gotten by information entropy, applying extension theory to evaluate risk and the level of risk in building construction project is obtained. Finally, an example is provided to verify reliability of the method, giving some reference for security risk evaluation of building construction project.
