作者：
Wang, Xinzhong;Li, Linshu;Xiang, Yi;Wu, Yuexing;Wei, Mei
期刊：
Frontiers in Materials,2024年10 ISSN：2296-8016
通讯作者：
Wang, XZ
作者机构：
[Li, Linshu; Wang, XZ; Wang, Xinzhong; Wu, Yuexing; Xiang, Yi] Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.;[Wei, Mei] Hunan Arts & Crafts Vocat Coll, Sch Digital Arts, Yiyang, Peoples R China.
通讯机构：
[Wang, XZ ] H;Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.
关键词：
concrete-filled steel tube;basalt fiber;short columns;finite element analysis;bearing capacity;ductility coefficient
摘要：
With rapid economic and social development, both concrete-filled steel tube (CFST) composite structures and basalt fiber (BF) have been widely applied in the field of civil engineering. To investigate the laws and characteristics of the influence of chopped BF on the mechanical properties of CFST columns and further promote the application of BF in CFST structures, the axial compressive bearing capacity test of 18 CFST short columns was carried out, and the influence of BF of different lengths on their structural mechanical properties was analyzed. The test results were compared with the theoretical calculation results and the finite element analysis results to verify the reasonableness of the test results. The results reveal that the axial compressive bearing capacity of the CFST short column after adding BF is significantly improved compared to the ordinary CFST short column, in which the bearing capacity and the ductility coefficient are increased by approximately 8.1% and 31.6%, respectively, on average. In addition, changing the length of BF has less effect on the bearing capacity of CFST short columns, the rate of increase in bearing capacity decreases with an increase in the steel ratio of CFST, and the coefficient of ductility increases with the increase in the steel ratio.
关键词：
Asphalt mixture;Mesoscopic analysis;Skeleton evolution;Aggregate contact;Particle movement;Discrete element method
摘要：
The aggregate skeleton is the intrinsic core of asphalt mixtures for load transfer, which is quite different under various gradations. For evaluating the loading characteristics of the aggregate skeleton, this research combined the 3D blue -ray scanning technology and discrete element method (DEM) to establish the numerical models of different graded asphalt mixtures considering the real aggregate morphology. A linear parallel bond model was used to simulate the adhesion effect of asphalt, and the uniaxial compression numerical simulation was verified by indoor tests. In addition, the contact force, contact number, anisotropy, and rotation angle were used to evaluate the aggregate skeleton evolution under uniaxial compression loading. Furthermore, the contribution of each grade aggregate in the gradation to the skeleton structure was analyzed. Results show that the average contact force is higher in large -size aggregates above 9.5 mm, which exhibit greater load transfer efficiency. Moreover, 4.75-9.5 mm size aggregates combine the functions of bearing and filling, and its role is significantly affected by the gradation. It is also found that the internal skeleton structure can be optimized and adjusted under stress. The contact numbers of different graded mixtures follow a close decrease, and the strong contacts are mostly provided by coarse aggregates above 4.75 mm. The anisotropy development of aggregate skeleton contact force is induced by the stress, and the deviator fabric of asphalt mixtures show a good linear positive correlation with the uniaxial compressive strength (UCS). Besides, fine aggregates exhibit greater cumulative rotation angle and instability effect, it is feasible to detect asphalt mixture deformation by the rotation angle of particles.
通讯机构：
[Zhang, L ] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;Hunan Univ Technol, Hunan Engn Res Ctr Struct Safety & Disaster Preven, Yiyang 413000, Peoples R China.
关键词：
boulder and hard rock environment;GPR;wavelet scale energy spectrum;wavelet packet energy;time-frequency characteristics
摘要：
The hard rocks in the stratum can pose safety risks and hinder the progress of urban underground tunnel construction using shield and jacking methods, thereby reducing construction efficiency and increasing construction costs. This paper utilizes wavelet scale energy spectrum, wavelet packet theory and statistical methods to conduct research on the detection of special geological formations such as hard rocks and voids, as well as the analysis of their signal time-frequency characteristics based on the ground-penetrating radar (GPR) technique. On the basis of calibrating the permittivity of different types of rock blocks, we established a forward model for detecting hard rocks and voids, and the simulated signals were analyzed in the time and frequency domains. Subsequently, laboratory experiments were conducted to perform GPR tests on different types of hard rocks in natural and water-saturated states and voids, to explore the time-frequency characteristics, frequency band energy variations, and statistical patterns of typical single-trace signals. The results show that the granite detection signal contains more low-frequency components, the sandstone detection signal contains more medium-low frequency components, while the limestone detection signal contains more medium-high frequency components in their natural state; the signal from the karst cave has relatively more low-frequency components than the signal from the empty cavity. The geometric shape of the rock has no influence on the dominant frequency and time-frequency distribution of its reflection signal. Generally, rocks with higher rebound values (hardness) also exhibit larger variance and standard deviation in frequency band energy. The research has important theoretical significance and practical value for the measurement and assessment of special geological features such as hard rocks and voids in urban underground trenchless construction.
期刊：
Bulletin of Engineering Geology and the Environment,2024年83(3):1-15 ISSN：1435-9529
通讯作者：
Hu, HX;Deng, C
作者机构：
[Xie, Zhongliang; Cai, Yuehui; Hu, Huanxiao; Lu, Yufan; Gan, Benqing] Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol E, Changsha 410083, Peoples R China.;[Xie, Zhongliang; Cai, Yuehui; Hu, Huanxiao; Lu, Yufan; Gan, Benqing] Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.;[Deng, Chao] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Deng, C ] H;[Hu, HX ] M;Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol E, Changsha 410083, Peoples R China.;Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.
摘要：
The grouting technique has been widely applied in geotechnical engineering. However, due to the concealed nature of underground engineering, there is relatively limited research on the diffusion characteristics of grout in sandy soil. This study utilized a self-developed three-dimensional grouting model test system. Experiments tests were conducted using standard sand and different water-cement (w/c) ratios of grout under limited boundary conditions, diffusion mechanism of sand soil grouting revealed. It was found that lower w/c ratios require higher grouting pressure when injecting grout into the sandy soil. The grouting pressure exhibited a pulsating pattern over time and a grouting pressure up to 323.9 kPa at w/c = 0.6. The grouting diffusion pattern under all w/c ratio conditions displayed typical columnar diffusion, and there was a good linear relationship between the average diffusion radius of the grout and the w/c ratio; the average diffusion radius was between 121 and 208 mm. The volume of the grout bulbs varied significantly at different w/c ratios, decreasing as the w/c ratio increased. With increased grouting pressure and w/c ratio, the dewatering effect during the grouting process became more pronounced, and the bleeding rate of the slurry with w/c = 1.4 (67.1%) is more than six times that of the w/c = 0.6 (10.5%). The results show that the uplift displacement on the soil surface exhibited certain hysteresis, and the grouting lifting process in sandy soil was divided into three stages: initial deformation, accelerated uplift, and stable uplift.
摘要：
To estimate the progressive collapse resistance capacity of a multi-column frame tube structure with an assembled truss beam composite floor (ATBCF), pushdown analysis and nonlinear dynamic analysis are conducted for such a structure using the alternate load path (ALP) method. The bearing capacities of the remaining structures under three different work conditions, which are the side middle column removal, the edge middle column removal, and the corner column removal, are individually studied, and the collapse mechanism of the remaining structures is analyzed based on the aspects of the internal force redistribution and the failure mode of the second defense line. Simultaneously, the influence of the column failure time on the dynamic response of the remaining structure and the dynamic amplification coefficient is discussed. The results indicate that the residual bearing capacity of the remaining structure following the bottom corner column removal is higher than that of the one following the side or edge middle column removal, while the latter has a stronger plastic deformation capacity. When the ALP method is adopted to operate the progressive collapse analysis, it is reasonable to take the column failure time as 0.1 times the period of the first-order vertical vibration mode of the remaining structure, and it is suitable to set the dynamic amplification coefficient as 2.0, which is the ratio of the maximum dynamic displacement to the static displacement of the remaining structure under the transient loading condition.
摘要：
The fatigue crack propagation behaviour of Q550E high-performance steel (HPS) is studied in this paper. Static tensile testing and fatigue crack propagation testing were carried out, and the results were compared with those of Q235. Finite element models were developed and verified against the experimental results. The impacts of the initial crack angle, crack depth ratio, stress ratio, thickness, and corrosion pitting on the fatigue crack propagation behaviour of the HPS were analysed. The results show that the fatigue life of Q550 was reduced by 18% due to the corrosion pitting, but it did not change the crack propagation path. When the stress intensity factor is higher than a certain value, the fatigue performance of Q235 is better than that of Q550E. The initial crack angle of 52.5 & DEG; is the critical angle of the crack stress intensity factor. The steel tends to fracture as the crack depth ratio increases, and more attention should be paid to the effective crack length in engineering practice. An increasing stress ratio leads to a smaller stress intensity factor, and the thickness affects the stress intensity factor in the later stage. The crack stress intensity factor around the corrosion pits gradually decreases along the thickness direction, and the crack tips around the corrosion pits tend to reach the yield state initially, accelerating the fatigue fracture of the specimen and ultimately leading to a decrease in fatigue life.
摘要：
Efflorescence is a concerning issue in geopolymer formulations. By accelerating efflorescence, the efflorescence behavior and compressive strength evolution were analyzed for metakaolin (MK)-based geopolymers cured at various temperatures and times. Mercury Intrusion Porosimetry (MIP) was the primary characterization method utilized in this study. Based on the pore structure, we identified the influence of pore structure on efflorescence behavior and compressive strength evolution. Those results showed that long-term and initial high-temperature curing played a negative role in mitigating efflorescence. Long-term curing refined the pore size, facilitating alkali salt migration to the surface. Initial high-temperature curing enhanced pore connectivity, which facilitated alkali salt movement. The number of pores below 20 nm governs the effect of efflorescence on compressive strength. Crystallization degrades geopolymer with a large number of pores below 20 nm. This study provides a new understanding of the effect of pore structure on efflorescence and the evolution of compressive strength during efflorescence and facilitates optimization of geopolymer formulations to relieve efflorescence.
通讯机构：
[Jianrong Cai] S;School of Civil Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Reversible lanes constitute an important solutions for sustainable transportation, with the aim to solve the practical problem of reversible lane optimization of urban road networks constrained by adjustment time. Considering the relationship between the number of lanes and the capacity of sections, a mixed-integer bilevel programming model of reversible lane optimization constrained by adjustment time is constructed in order to minimize the total travel time of the system. The results show that the model can effectively obtain the optimal strategy for any number of reversible sections subject to adjustment time constraints. With the increase of the number of reversible sections that can be optimized within the adjustment time, the cumulative reduced system time increases monotonically and the road network optimization effect improves, but as a whole, the optimization effect of the newly added reversible sections in each stage shows a decreasing trend. When the number of reversible sections that can be optimized within the adjustment time reaches a certain number, increasing the number of reversible sections will have a limited further effect on the overall system. For the reversible lane optimization problem of urban road networks, only efficient reversible sections need to be optimized to achieve a good optimization effect.
通讯机构：
[Sen Lin] S;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
作者机构：
[Luo, Xiaoyong; Long, Hao; Dong, Shuang; Luo, XY; Liu, Jinhong] Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;[Long, Hao] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Luo, Xiaoyong; Luo, XY] Cent South Univ, Hunan Prefabricated Bldg Engn Technol Res Ctr, Changsha 410000, Peoples R China.
通讯机构：
[Luo, XY ] C;Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;Cent South Univ, Hunan Prefabricated Bldg Engn Technol Res Ctr, Changsha 410000, Peoples R China.
关键词：
prefabricated components;tolerance;manufacturing dimensions;dimensional chain;monte carlo method;installation reliability
摘要：
During the installation process of prefabricated components, deviations in dimensions and installation positions can occur due to construction quality issues, and the accumulation of these deviations can impact the reliability of component installation. However, the current approach to addressing accumulated deviations in the component installation process primarily relies on the trial-and-error method, lacking a solid theoretical foundation. This paper introduces the dimensional chain theory derived from mechanical engineering and presents a method to evaluate the installation reliability of prefabricated components in concrete structures. First, based on extensive measurements of installation deviations, it was found that the installation deviations of components followed a log-normal distribution. By analyzing the relationship between installation deviations and the acceptance rate, it was determined that for a 90% acceptance rate, the installation position deviation should be 8.6 mm for prefabricated wall panel components and 7.3 mm for prefabricated column components. Subsequently, the concept of dimensional chain theory from mechanical engineering was introduced to establish a limit state equation for quantifying the installation reliability of prefabricated components in concrete structures. By applying this theory, appropriate component fabrication dimensions could be determined to achieve a 95% level of installation reliability. Finally, by using the Monte Carlo method to solve the installation limit state equation for an actual engineering project, recommended fabrication dimensions for the components were obtained. The results indicate that within the horizontal axis, the length deviation of prefabricated beams, and the width fabrication dimension of columns needed to be reduced by 2.3 mm to 2.9 mm. Within the vertical axis, the length dimension of columns and the height dimension of beams had to be reduced by 0.9 mm to 2.2 mm to achieve a 95% level of installation reliability.
期刊：
Advances in Civil Engineering,2023年2023 ISSN：1687-8086
通讯作者：
Wang, YK
作者机构：
[Wang, YK; Wang, Yukui; Zhang, Dan] Hunan City Univ, Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413099, Peoples R China.;[Yan, Shijun] Hunan City Univ, Coll Mech & Elect Engn, Yiyang 413000, Peoples R China.;[Zhang, Dan] Hunan City Univ, Key Lab Green Bldg & Intelligent Construct Higher, Yiyang 413000, Peoples R China.;[Hu, Zhangqi] Hunan City Univ, Coll Civil Engn, Yiyang 413099, Peoples R China.
通讯机构：
[Wang, YK ] H;Hunan City Univ, Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413099, Peoples R China.
关键词：
Introduction;Materials and Methods;Results;Discussion;Conclusion;Abstract;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interests;Authors’ Contributions;Funding Statement;Acknowledgements;Acknowledgments;Supplementary Materials;Reference;Dataset Description;Dataset Files;Abstract;Introduction;Introduction and Materials;Introduction and Methods;Materials;Materials and Methods;Methods;Results;Discussion;Results and Discussion;Discussion and Conclusion;Results and Conclusion;Conclusion;Conclusions;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interest;Authors’ Contributions;Funding Statement;Acknowledgements;Supplementary Materials;References;Appendix;Abbreviations;Preliminaries;Introduction and Preliminaries;Notation;Proof of Theorem;Proofs;Analysis of Results;Examples;Numerical Example;Applications;Numerical Simulation;Model;Model Formulation;Systematic Palaeontology;Nomenclatural Acts;Taxonomic Implications;Experimental;Synthesis;Overview;Characterization;Background;Experimental;Theories;Calculations;Model Verification;Model Implementation;Geographic location;Study Area;Geological setting;Data Collection;Field Testing;Data and Sampling;Dataset;Literature Review;Related Works;Related Work;System Model;Methods and Data;Experimental Results;Results and Analysis;Evaluation;Implementation;Case Presentation;Case Report;Search Terms;Case Description;Case Series;Background;Limitations;Additional Points;Case;Case 1;Case 2 etc.;Concern Details;Retraction Details;Copyright;Related Articles
摘要：
The research group utilized the estimation model of energy consumption capacity for reinforced concrete components without axial force to assess the energy consumption capacity of 92-reinforced concrete components from the PEER database, which were subjected to axial force and bending. The study also examined the impact of design parameters, including longitudinal reinforcement ratio, transverse reinforcement ratio, axial compression ratio, and shear-span ratio, on the estimation results. The research findings revealed that when applying the estimation model of energy consumption capacity for reinforced concrete components without axial force to calculate the energy consumption capacity of reinforced concrete components with axial force, there was a significant deviation rate in the estimation of cumulative energy consumption. The relationship between the deviation rate of cumulative energy consumption and longitudinal reinforcement ratio, axial compression ratio, and shear-span ratio remained unclear. However, a more apparent linear relationship was observed with the transverse reinforcement ratio. By conducting a quantitative analysis of the transverse reinforcement ratio, the researchers proposed an modified estimation model of energy consumption capacity for reinforced concrete components with axial force. Nonetheless, the accuracy of the modified estimation model was found to be high within the range of 0–250,000 kN mm of cumulative energy consumption. For cumulative energy consumption exceeding 250,000 kN mm, further experimental and theoretical research is still required to enhance the reliability of the modified estimation model.
期刊：
Water Supply,2023年23(9):3761–3774. ISSN：1606-9749
通讯作者：
Qian, DY
作者机构：
[Cao, Yanmin] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Qian, Dongyue] Tianjin Acad Water Transportat Engn, Minist Transport, Tianjin 300456, Peoples R China.;[Wang, Chongyu] Hunan Water Planning & Design Inst Co Ltd, Changsha 410008, Hunan, Peoples R China.
通讯机构：
[Qian, DY ] T;Tianjin Acad Water Transportat Engn, Minist Transport, Tianjin 300456, Peoples R China.
关键词：
contribution rate;cross city driving force;water quality factor;Xiang River Basin
摘要：
Based on the monthly monitoring data of 16 water quality monitoring stations in the Xiang River Basin from 1990 to 2020, the Mann-Kendall test was used to analyze dissolved oxygen, 5-day biochemical oxygen demand, permanganate index, total phosphorus, ammonia nitrogen, cadmium, arsenic, and hexavalent chromium. The changing trend of nine indicators, including the stepwise regression method, was used to determine the cross city driving force of each water quality index, and the contribution rate (weight) of each driving force was obtained by principal component analysis. The research results show that (1) agriculture in Yongzhou is the main driving force, and its contribution rate is 67.2%; (2) urbanization has a greater impact on the driving process of the water environment in the Xiang River Basin, and its contribution rate is as follows: Changsha (83%) > Hengyang (80.7%) > Pingxiang (63.7%) > Chenzhou (60.9%) > Xiangtan (57.4%) > Zhuzhou (50%) > Loudi (48.5%); (3) the urbanization of Zhuzhou City and Loudi City's urban sewage discharge not only has an impact on the city's water environment, but also drives the water environment in the downstream Xiangtan area. The research results can provide a basis and reference for the study of water environmental governance in the basin.
作者机构：
[Zhong, Dou; Liu, Jing; Wang, YK; Wang, Yukui; Zhang, Dan; Hu, Zhangqi] Hunan City Univ, Coll Civil Engn, Yiyang 413099, Peoples R China.;[Wang, YK; Wang, Yukui] Hunan City Univ, Key Lab Green Bldg & Intelligent Construct, Higher Educ Inst Hunan Prov, Yiyang 413000, Peoples R China.;[Liu, Jing; Zhang, Dan; Hu, Zhangqi] Hunan City Univ, Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413099, Peoples R China.
通讯机构：
[Wang, YK ] H;Hunan City Univ, Coll Civil Engn, Yiyang 413099, Peoples R China.;Hunan City Univ, Key Lab Green Bldg & Intelligent Construct, Higher Educ Inst Hunan Prov, Yiyang 413000, Peoples R China.
关键词：
Introduction;Materials and Methods;Results;Discussion;Conclusion;Abstract;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interests;Authors’ Contributions;Funding Statement;Acknowledgements;Acknowledgments;Supplementary Materials;Reference;Dataset Description;Dataset Files;Abstract;Introduction;Introduction and Materials;Introduction and Methods;Materials;Materials and Methods;Methods;Results;Discussion;Results and Discussion;Discussion and Conclusion;Results and Conclusion;Conclusion;Conclusions;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interest;Authors’ Contributions;Funding Statement;Acknowledgements;Supplementary Materials;References;Appendix;Abbreviations;Preliminaries;Introduction and Preliminaries;Notation;Proof of Theorem;Proofs;Analysis of Results;Examples;Numerical Example;Applications;Numerical Simulation;Model;Model Formulation;Systematic Palaeontology;Nomenclatural Acts;Taxonomic Implications;Experimental;Synthesis;Overview;Characterization;Background;Experimental;Theories;Calculations;Model Verification;Model Implementation;Geographic location;Study Area;Geological setting;Data Collection;Field Testing;Data and Sampling;Dataset;Literature Review;Related Works;Related Work;System Model;Methods and Data;Experimental Results;Results and Analysis;Evaluation;Implementation;Case Presentation;Case Report;Search Terms;Case Description;Case Series;Background;Limitations;Additional Points;Case;Case 1;Case 2 etc.;Concern Details;Retraction Details;Copyright;Related Articles
摘要：
In order to study seismic design process of RC (reinforced concrete) column components considering the effect of earthquake duration, the degradation law of capacity under random amplitude hysteresis history was conducted by the research group, and the estimation method for the energy dissipation capacity of RC column components was suggested. Furthermore, the correlation between the stiffness decay index and energy dissipation capacity, hysteresis histories, and structural parameters was proposed, and the performance classification criteria based on the stiffness decay index was established. On this basis, the connection between the stiffness decay index and structural parameters and seismic parameters was established, and the seismic design process of RC column components in SDOF (single degree of freedom) system was proposed. The research indicated that the proposed seismic design process based on stiffness decay index can effectively consider the effect of earthquake duration. The stiffness decay index is more suitable for defining structural damage than deformation index and Park-Ang index. The stiffness decay index establishes quantitative relationships with seismic parameters and structural parameters, facilitating performance-based design in engineering practice. The increase in earthquake duration exacerbates the damage of RC column components, and this effect is more pronounced at the beginning of the earthquake and gradually decreases over time.
通讯机构：
[Jianbo Yuan] S;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Based on analytical and simulation methods, this paper discusses the path choice behavior of mixed traffic flow with autonomous vehicles, advanced traveler information systems (ATIS) vehicles and ordinary vehicles, aiming to promote the development of autonomous vehicles. Firstly, a bi-level programming model of mixed traffic flow assignments constrained by link capacity is established to minimize travel time. Subsequently, the algorithm based on the incremental allocation method and method of successive averages is proposed to solve the model. Through a numerical example, the road network capacity under different modes is obtained, the impact of market penetration on travel time is analyzed, and the state and characteristics of single equilibrium flow and mixed equilibrium flow are explored. Analysis results show that the road network can be maximized based on saving travel time when all vehicles are autonomous, especially when the autonomous lane is adopted. The travel time can be shortened by increasing the market penetration of autonomous vehicles and ATIS vehicles, while the former is more effective. However, the popularization of autonomous vehicles cannot be realized in the short term; the market penetration of autonomous vehicles and ATIS vehicles can be set to 0.2 and 0.6, respectively, during the introduction period.
期刊：
Construction and Building Materials,2023年376:131077 ISSN：0950-0618
通讯作者：
Yiming Yang<&wdkj&>Huang Tang
作者机构：
[Tang, Huang; Yang, Yiming] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Peng, Jianxin; Yang, Yiming] Minist Educ, Key Lab Safety Control Bridge Engn, Changsha 410114, Hunan, Peoples R China.;[Yang, Yiming] State Key Lab Performance Monitoring & Protecting, Nanchang 330096, Jiangxi, Peoples R China.;[Yang, Yiming] Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413000, Hunan, Peoples R China.;[Liu, Zhanghong] Jiangxi Ganyue Expressway Co Ltd, Nanchang 330096, Jiangxi, Peoples R China.
通讯机构：
[Yiming Yang; Huang Tang] S;School of Civil Engineering, Hunan City University, Yiyang, Hunan 413000, China<&wdkj&>Key Laboratory of Safety Control of Bridge Engineering, Ministry of Education, Changsha, Hunan 410114, China<&wdkj&>State Key Laboratory for Performance Monitoring and Protecting of Rail Transit Infrastructure, Nanchang, Jiangxi 330096, China<&wdkj&>Hunan Engineering Research Center of Development and Application of Ceramsite Concrete Technology, Yiyang, Hunan 413000, China<&wdkj&>School of Civil Engineering, Hunan City University, Yiyang, Hunan 413000, China
摘要：
Reasonable assessment of the failure probability caused by long-term deflection is essential to ensure the service performance of low shrinkage-creep concrete (LSCC) structures. In this paper, the shrinkage and creep models applicable to LSCC are proposed and verified by comparing their results with the experimental data. Then, the non-stationary evolution models of uncertainties of concrete creep and shrinkage are developed. Finally, a long-term deflection-based assessment method of failure probability of LSCC structures is also proposed considering the effect of non-stationary evolution of creep and shrinkage uncertainties. The case analysis results show that ignoring the effect of the non-stationary evolution of creep and shrinkage uncertainties overestimates the long-term deflection, and the deviation in this case study is 10.13%. Compared with the uncertainty of creep, the cumulative failure probability of the case structure is more sensitive to the non-stationary evolution of shrinkage uncertainty. The use of LSCC can greatly reduce the cumulative failure probability of concrete structures caused by excessive long-term deflection. Additionally, the cumulative failure probability of concrete structures is greatly underestimated by using the traditional characteristic parameters of uncertainties of concrete creep and shrinkage.
作者机构：
[Liang, Xiaoqiang; Yang, Xian; Hu, Da; Li, Yongsuo; Hu, D] Hunan City Univ, Hunan Engn Res Ctr Struct Safety & Disaster Preven, Yiyang 413000, Peoples R China.;[Yi, Shun; Liang, Xiaoqiang; Yang, Xian; Hu, Da; Hu, Yongjia; Hu, D] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;[Hu, Da; Hu, D] Power China Zhongnan Engn Co Ltd, Hunan Prov Key Lab Key Technol Hydropower Dev, Changsha 410014, Peoples R China.
通讯机构：
[Hu, D ] H;Hunan City Univ, Hunan Engn Res Ctr Struct Safety & Disaster Preven, Yiyang 413000, Peoples R China.;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;Power China Zhongnan Engn Co Ltd, Hunan Prov Key Lab Key Technol Hydropower Dev, Changsha 410014, Peoples R China.
摘要：
To provide theoretical support for the safety control of rectangular pipe jacking tunnels crossing an existing expressway, a method for predicting the surface settlement of a rectangular pipe jacking tunnel is proposed in this study. Therefore, based on the high approximation of the BP neural network to any function under the multiparameter input, the PSO-BP mixed prediction model of the ground subsidence of the ultrashallow buried large section rectangular pipe jacking tunnel is established by taking into account the adaptive mutation method, adopting the improved particle swarm optimization (IPSO) algorithm with adaptive inertia weight and mutation particles in the later stage to determine the optimal hyperparameters of the prediction model. Through the case study of an ultrashallow large cross-section rectangular pipe jacking tunnel, this algorithm is compared with the traditional algorithm and combined with field monitoring data for analysis and prediction. The prediction results show that compared with the traditional BP neural network prediction model, AWPSO-BP model and PWPSO-BP model, the improved PSO-BP mixed prediction model shows a more stable prediction effect when the change in surface subsidence is gentle and the concavity and convexity are large. The predicted subsidence value is close to the actual value, and the accuracy and robustness of the prediction are significantly improved.
摘要：
The vacuum preloading method effectively strengthens soft soil foundations with vertical drainage, which produces a smear effect when laying sand drains. Meanwhile, the seepage of pore water and soil deformation during consolidation exhibit nonlinear characteristics. Therefore, based on Gibson's 1D large-strain consolidation theory, this paper developed a more generalized large-strain radical consolidation model of sand-drained soft foundations under free-strain assumptions. In this system, the double logarithmic compression permeability relationships for soft soils with large-strain properties, the variation in the radical permeability coefficient in the smear zone, and the effect of the non-Darcy flow were all included. Then, the partial differential control equations were numerically solved by the finite difference method and validated with existing radical consolidation test results and derived analytical solutions. Finally, the influences of relevant model parameters on consolidation are discussed. The analysis shows that the greater the maximum dimensionless vacuum negative pressure P0, the faster the consolidation rate of sand-drained foundations. Meanwhile, the decrease in the negative pressure transfer coefficient k1 will result in a decreasing final settlement amount. Moreover, the consolidation rate of sand-drained foundations is slower considering the non-Darcy flow, but the final settlement is unaffected.
期刊：
Energy Science & Engineering,2023年11(9):3185-3203 ISSN：2050-0505
通讯作者：
Wang, G
作者机构：
[Liu, Ronghua; Chen, Yong; Wang, Pengfei] Hunan Univ Sci & Technol, Sch Resource & Environm & Safety Engn, Xiangtan, Hunan, Peoples R China.;[Liu, Ronghua; Chen, Yong; Wang, Pengfei] Work Safety Key Lab Prevent & Control Gas & Roof D, Xiangtan, Hunan, Peoples R China.;[Wu, Jiaokun; Chen, Yong] Natl Key Lab Gas Disaster Detecting Preventing & E, Chongqing, Peoples R China.;[Wu, Jiaokun; Chen, Yong] China Coal Technol Engn Grp Chongqing Res Inst, Chongqing, Peoples R China.;[Wang, Gang; Chen, Yong] Shandong Univ Sci & Technol, State Key Lab Strata Intelligent Control & Green M, Qingdao, Peoples R China.
通讯机构：
[Wang, G ] S;Shandong Univ Sci & Technol, State Key Lab Strata Intelligent Control & Green M, 579, Qianwangang Rd, Qingdao 266590, Shandong, Peoples R China.;Shandong Univ Sci & Technol, Minist Sci & Technol, 579, Qianwangang Rd, Qingdao 266590, Shandong, Peoples R China.
关键词：
degree of metamorphism;gas desorption;pore volume;primary coal;specific surface area
摘要：
Exploring the pore and gas desorption characteristics of primary coal with different degrees of metamorphism. Abstract Pore difference characteristics and adsorption/desorption experiments of primary coal with different degrees were explored to study the characteristics of pore structure and gas desorption. The results show that the pore volume increases with the increase in the degree of metamorphism. In primary coal with different degrees of metamorphism, the distribution of micropores, small pores, and medium‐sized pores (by volume) is WY < PM < CY. The distribution of large pore volume and visible pore volume was WY > PM > CY. According to the pore volume distribution law of different metamorphic primary coals, the average pore diameters of WY, PM, and CY were 68.40, 45.60, and 30.50 nm, respectively. The porosity and specific surface area of primary coal with different degrees of metamorphism show a distribution pattern such that WY > PM > CY. For large pore and visible pore, the pore volumes of WY, PM, and CY coal were 0.0785, 0.0587, and 0.0300 mL/g, respectively, and the proportions were 81.86%, 74.49%, and 55.25%, respectively. The porosity of WY, PM, and CY were 11.57%, 9.03%, and 6.57%, respectively, and the specific surface areas were 6.917, 5.826, and 5.611 cm3/g. According to the desorption characteristics of coal bodies with different metamorphic degrees at different time nodes found that the gas desorption at different time nodes shows similar changes under the same adsorption equilibrium pressure. The higher the degree of coal metamorphism, the greater the amount of gas desorption, and the faster the desorption amplitude. The desorption intensity of WY coal is significantly higher than that of PM and CY coal with the increase of desorption time which also verifies the measurement results of pore structure and adsorption constant.
