This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling...This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.展开更多
Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. ...Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. e., cannot reflect various regulations of settlement at some stages or the entire process). In this study,the correlation coefficient,maximum error values,and other values were obtained according to the fitting and predicted results of a single model. The coefficient of variation was then introduced to determine the weight of each model forming the combination. The proposed model was used to fit and predict for settlement and overcome the issue of utilizing a single model while determining the weight. The fitting predictive effect was also analyzed using the settlement fitting precision results. The fitting precision of optimizing the combination model is high. The predicted data of the post-construction settlement are closer to the calculated value of the settlement monitoring data. Moreover,the proposed model has good practicability,does not require the interval data of settlement,and restricts the model number. Thus,this model can be applied in the engineering field.展开更多
An experimental program is conducted on model piled rafts in sand soil.The experimental program is aimed to investigate the behavior of raft on settlement reducing piles.The testing program includes tests on models of...An experimental program is conducted on model piled rafts in sand soil.The experimental program is aimed to investigate the behavior of raft on settlement reducing piles.The testing program includes tests on models of single pile,unpiled rafts and rafts on 1,4,9,or 16 piles.The model piles beneath the rafts are closed ended displacement piles installed by driving.Three lengths of piles are used in the experiments to represent slenderness ratio,L/D,of 20,30 and 50,respectively.The dimensions of the model rafts are 30 cm×30 cm with different thickness of 0.5 cm,1.0 cm or 1.5 cm.The raft-soil stiffness ratios of the model rafts ranging from 0.39 to 10.56 cover flexible to very stiff rafts.The improvement in the ultimate bearing capacity is represented by the load improvement ratio,LIR,and the reductions in average settlement and differential settlement are represented by the settlement ratio,SR,and the differential settlement ratio,DSR,respectively.The effects of the number of settlement reducing piles,raft relative stiffness,and the slenderness ratio of piles on the load improvement ratio,settlement ratio and differential settlement ratio are presented and discussed.The results of the tests show the effectiveness of using piles as settlement reduction measure with the rafts.As the number of settlement reducing piles increases,the load improvement ratio increases and the differential settlement ratio decreases.展开更多
A one-dimensional consolidation-creep model test on the creep deformation of soft muddy clay in the littoral area of Tianjin is performed. A nonlinear rheologic model is established and the model coefficients are dete...A one-dimensional consolidation-creep model test on the creep deformation of soft muddy clay in the littoral area of Tianjin is performed. A nonlinear rheologic model is established and the model coefficients are determined, in consideration of the characteristics of soft muddy clay. Furthermore, a settlement equation is deduced from the theologic model and verified by the field settlement measurements of Beitang Reservoir dam in Tianjin littoral area. Finally, the settlement e- quation is applied in calculating the settlement of ＂FAIRWAY-＂ suction dredger, which sunk in the external channel of Tianjin Port, induced by the soft clay consolidation of seabed. These results provide useful information for the decision of salvage plan.展开更多
Settlement control of high-speed railways is a key technology in embankment engineering. In order to reveal the engineering characteristics of the deep, completely decomposed granite soil in the Hainan East Ring Railw...Settlement control of high-speed railways is a key technology in embankment engineering. In order to reveal the engineering characteristics of the deep, completely decomposed granite soil in the Hainan East Ring Railway, four groups of centrifuge model tests were conducted. We studied the settlement properties, under the embankment action, of untreated subsoil, subsoil treated by dynamic compaction, and subsoil reinforced with cement-mixed piles. In particular, we examined the relationship between settlement and time, including the settlement during and after construction. The results show that the Weibull model can describe the relationship between embankment settlement and time well, and that the post-construction settlements of the subsoil meet the requirements of the relevant code. Among the two foundation treatment measures, dynamic compaction is more effective than reinforcement with cement-mixed piles. The tested pressure on the contact surface between embankment and subsoil was obviously different from the commonly used calculated values.展开更多
Rural human settlement is a significant indicator of the living standards of rural residents,and its improvement can contribute to promoting the positive interaction between inhabited environment and the social,econom...Rural human settlement is a significant indicator of the living standards of rural residents,and its improvement can contribute to promoting the positive interaction between inhabited environment and the social,economic,and resource environment in the countryside.Based on 557 valid questionnaires of satisfaction evaluation of human settlement in the peripheral metropolitan area of Beijing,this paper analyzed the elemental characteristics and factors influencing human settlement quality using multivariate statistical analysis and a structural equation model.The result shows that,first,the rural residents in a peripheral metropolitan area of Beijing are generally satisfied with the quality of human settlement(satisfaction rate is 66.2%).Specifically,the natural and social environment of the countryside is excellent and harmonious and corresponding standard of countryside infrastructure is advanced,but the quality of public services and follow-up management of facilities are in urgent need of improvement and the imbalance between revenue and expenditure of rural households has led to a continuous increase in the pressures of life.Second,factors such as social atmosphere,appearance of the village,entertainment,living costs,fundamental public services,and production costs have significant effects on human settlement quality in this peripheral metropolitan area,with social atmosphere as the main one.Living costs and supporting services are the main constraints to improvement in the quality of human settlement.展开更多
The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficultie...The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficulties in providing social services that meet the required standards, and the prolongation of emergencies. Despite this challenging context, short-term considerations continue to guide their planning and management rather than more integrated, longer-term perspectives, thus preventing viable, sustainable development. Over the years, the design of humanitarian settlements has not been adapted to local contexts and perspectives, nor to the dynamics of urbanization and population growth and data. In addition, the current approach to temporary settlement harms the environment and can strain limited resources. Inefficient land use and ad hoc development models have compounded difficulties and generated new challenges. As a result, living conditions in settlements have deteriorated over the last few decades and continue to pose new challenges. The stakes are such that major shortcomings have emerged along the way, leading to disruption, budget overruns in a context marked by a steady decline in funding. However, some attempts have been made to shift towards more sustainable approaches, but these have mainly focused on vague, sector-oriented themes, failing to consider systematic and integration views. This study is a contribution in addressing these shortcomings by designing a model-driving solution, emphasizing an integrated system conceptualized as a system of systems. This paper proposes a new methodology for designing an integrated and sustainable human settlement model, based on Model-Based Systems Engineering and a Systems Modeling Language to provide valuable insights toward sustainable solutions for displaced populations aligning with the United Nations 2030 agenda for sustainable development.展开更多
在一些修船企业建立的修船结算系统和电子价格库中,人工匹配结算编码步骤易出错且耗时长,直接影响结算效率。为解决该问题,提出一种基于多特征融合的修船结算编码智能匹配复合模型。采用来自变换器的双向编码器表示(Bidirectional Encod...在一些修船企业建立的修船结算系统和电子价格库中,人工匹配结算编码步骤易出错且耗时长,直接影响结算效率。为解决该问题,提出一种基于多特征融合的修船结算编码智能匹配复合模型。采用来自变换器的双向编码器表示(Bidirectional Encoder Representations from Transformers,BERT)模型将工程内容文本表示为词向量,采用卷积神经网络(Convolutional Neural Network,CNN)模型提取文本的局部特征,采用双向长短期记忆网络结合注意力机制(Bidirectional Long Short-Term Memory with Attention Mechanism,BiLSTM-Attention)模型提取上下文特征,得到对应的结算编码。试验结果表明,所提出的复合模型在整体准确率方面实现显著提升,充分证明该复合模型在处理复杂文本分类任务中的优势。展开更多
基金supported by the Research Funds for the Central Universities (Grant No. 2009B13514)the Doctoral Fund of the Ministry of Education of China (Grant No. 20100094110002)
文摘This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.
基金National Natural Science Foundations of China(Nos.41172236,41402243,and 40911120044)Basic Research Project of Jilin University,China(No.450060491448)
文摘Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. e., cannot reflect various regulations of settlement at some stages or the entire process). In this study,the correlation coefficient,maximum error values,and other values were obtained according to the fitting and predicted results of a single model. The coefficient of variation was then introduced to determine the weight of each model forming the combination. The proposed model was used to fit and predict for settlement and overcome the issue of utilizing a single model while determining the weight. The fitting predictive effect was also analyzed using the settlement fitting precision results. The fitting precision of optimizing the combination model is high. The predicted data of the post-construction settlement are closer to the calculated value of the settlement monitoring data. Moreover,the proposed model has good practicability,does not require the interval data of settlement,and restricts the model number. Thus,this model can be applied in the engineering field.
文摘An experimental program is conducted on model piled rafts in sand soil.The experimental program is aimed to investigate the behavior of raft on settlement reducing piles.The testing program includes tests on models of single pile,unpiled rafts and rafts on 1,4,9,or 16 piles.The model piles beneath the rafts are closed ended displacement piles installed by driving.Three lengths of piles are used in the experiments to represent slenderness ratio,L/D,of 20,30 and 50,respectively.The dimensions of the model rafts are 30 cm×30 cm with different thickness of 0.5 cm,1.0 cm or 1.5 cm.The raft-soil stiffness ratios of the model rafts ranging from 0.39 to 10.56 cover flexible to very stiff rafts.The improvement in the ultimate bearing capacity is represented by the load improvement ratio,LIR,and the reductions in average settlement and differential settlement are represented by the settlement ratio,SR,and the differential settlement ratio,DSR,respectively.The effects of the number of settlement reducing piles,raft relative stiffness,and the slenderness ratio of piles on the load improvement ratio,settlement ratio and differential settlement ratio are presented and discussed.The results of the tests show the effectiveness of using piles as settlement reduction measure with the rafts.As the number of settlement reducing piles increases,the load improvement ratio increases and the differential settlement ratio decreases.
基金the National Natural Science Foundation of China (Grant No.50579046)the Science and Technology Project of West China Traffic Construction (Grant No.200632800003-06)
文摘A one-dimensional consolidation-creep model test on the creep deformation of soft muddy clay in the littoral area of Tianjin is performed. A nonlinear rheologic model is established and the model coefficients are determined, in consideration of the characteristics of soft muddy clay. Furthermore, a settlement equation is deduced from the theologic model and verified by the field settlement measurements of Beitang Reservoir dam in Tianjin littoral area. Finally, the settlement e- quation is applied in calculating the settlement of ＂FAIRWAY-＂ suction dredger, which sunk in the external channel of Tianjin Port, induced by the soft clay consolidation of seabed. These results provide useful information for the decision of salvage plan.
文摘Settlement control of high-speed railways is a key technology in embankment engineering. In order to reveal the engineering characteristics of the deep, completely decomposed granite soil in the Hainan East Ring Railway, four groups of centrifuge model tests were conducted. We studied the settlement properties, under the embankment action, of untreated subsoil, subsoil treated by dynamic compaction, and subsoil reinforced with cement-mixed piles. In particular, we examined the relationship between settlement and time, including the settlement during and after construction. The results show that the Weibull model can describe the relationship between embankment settlement and time well, and that the post-construction settlements of the subsoil meet the requirements of the relevant code. Among the two foundation treatment measures, dynamic compaction is more effective than reinforcement with cement-mixed piles. The tested pressure on the contact surface between embankment and subsoil was obviously different from the commonly used calculated values.
基金supported jointly by the Key Research Program of the Chinese Academy of Sciences[grant number KZZD-EW-06-01]the State Key Program of National Natural Science of China[grant number 40830741]
文摘Rural human settlement is a significant indicator of the living standards of rural residents,and its improvement can contribute to promoting the positive interaction between inhabited environment and the social,economic,and resource environment in the countryside.Based on 557 valid questionnaires of satisfaction evaluation of human settlement in the peripheral metropolitan area of Beijing,this paper analyzed the elemental characteristics and factors influencing human settlement quality using multivariate statistical analysis and a structural equation model.The result shows that,first,the rural residents in a peripheral metropolitan area of Beijing are generally satisfied with the quality of human settlement(satisfaction rate is 66.2%).Specifically,the natural and social environment of the countryside is excellent and harmonious and corresponding standard of countryside infrastructure is advanced,but the quality of public services and follow-up management of facilities are in urgent need of improvement and the imbalance between revenue and expenditure of rural households has led to a continuous increase in the pressures of life.Second,factors such as social atmosphere,appearance of the village,entertainment,living costs,fundamental public services,and production costs have significant effects on human settlement quality in this peripheral metropolitan area,with social atmosphere as the main one.Living costs and supporting services are the main constraints to improvement in the quality of human settlement.
文摘The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficulties in providing social services that meet the required standards, and the prolongation of emergencies. Despite this challenging context, short-term considerations continue to guide their planning and management rather than more integrated, longer-term perspectives, thus preventing viable, sustainable development. Over the years, the design of humanitarian settlements has not been adapted to local contexts and perspectives, nor to the dynamics of urbanization and population growth and data. In addition, the current approach to temporary settlement harms the environment and can strain limited resources. Inefficient land use and ad hoc development models have compounded difficulties and generated new challenges. As a result, living conditions in settlements have deteriorated over the last few decades and continue to pose new challenges. The stakes are such that major shortcomings have emerged along the way, leading to disruption, budget overruns in a context marked by a steady decline in funding. However, some attempts have been made to shift towards more sustainable approaches, but these have mainly focused on vague, sector-oriented themes, failing to consider systematic and integration views. This study is a contribution in addressing these shortcomings by designing a model-driving solution, emphasizing an integrated system conceptualized as a system of systems. This paper proposes a new methodology for designing an integrated and sustainable human settlement model, based on Model-Based Systems Engineering and a Systems Modeling Language to provide valuable insights toward sustainable solutions for displaced populations aligning with the United Nations 2030 agenda for sustainable development.
文摘在一些修船企业建立的修船结算系统和电子价格库中,人工匹配结算编码步骤易出错且耗时长,直接影响结算效率。为解决该问题,提出一种基于多特征融合的修船结算编码智能匹配复合模型。采用来自变换器的双向编码器表示(Bidirectional Encoder Representations from Transformers,BERT)模型将工程内容文本表示为词向量,采用卷积神经网络(Convolutional Neural Network,CNN)模型提取文本的局部特征,采用双向长短期记忆网络结合注意力机制(Bidirectional Long Short-Term Memory with Attention Mechanism,BiLSTM-Attention)模型提取上下文特征,得到对应的结算编码。试验结果表明,所提出的复合模型在整体准确率方面实现显著提升,充分证明该复合模型在处理复杂文本分类任务中的优势。
