bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite element analysis of mechanics performance for GFRP beam-column joints connected by angle steel with slotted-hole
Authors: Wang Yan , Xiao Xiao , Yin Xiangdong , Fang Yaochu
Published: June 2021

In this paper, a group of GFRP beam-column joints connected with slotted-hole angle steel were analysed under monotonic loading. Based on ABAQUS software, the nonlinear finite element analysis of slotted-hole on beam for GFRP joint and influence of different slotted-hole lengths on mechanical properties of joints were carried out. Considering influence of friction and pretightening force, a conventional circular hole specimen C1 and three specimens K2, K3 and K4 with slotted-hole lengths of 2mm, 4mm and 6mm were designed. The universal contact element and pretension element were applied on ABAQUS finite element modeling of bolted connections. Finally, differences in failure mode, moment-rotation curve, rotational capacity, displacement ductility coefficient and other aspects between angle steel joints with conventional round holes and those with different slotted-hole sizes were compared. The results show that: 1) the rotational capacity of slotted-hole joints was about 6%-19% higher than that of ordinary round-hole joints. The longer the slotted-hole length is, the larger the plastic rotation angle steel will be. However, too large slotted-hole size will also cause excessive deformation of components and collapse.2) The slotted-hole method will not increase bearing capacity of joints, but displacement ductility coefficient of joint K4 with slotted-hole size of 6mm was 1.17 times that of conventional joint C1 with circular hole.
Basic test of mix proportion of foamed concrete with aluminum powder as foaming agent
Authors: Zhou Yueyang , Jin Guangri
Published: June 2021

In this paper, the method of producing bubbles by the reaction of aluminum powder and sodium hydroxide is used to make foam concrete test blocks and test their expansion rate and compressive strength. The foamed concrete was made through experiments of controlling the amount of cement, water and the relative content of aluminum powder, and the best mix ratio was selected from the comparative analysis of the compressive strength of 7d, 14d and 28dconcrete. Experimental results: The amount of cement and the water-cement ratio and the relative content of aluminum powder have a significant impact on the compressive strength and expansion rate. Conclusion: Starting from the ratio of the relative content of aluminum powder in foamed concrete to the amount of cement, the analysis of compressive strength and expansion rate provides a theoretical basis for the future study of its mix ratio, which greatly shortens the test time and saves costs.
Comprehensive evaluation system of transmission tower foundation safety
Authors: Wang Hanxiao , Tu Zhibin , Yao Jianfeng , Ding Mengjiao , Lu Bin , Chen Siyu
Published: June 2021

With the expansion of power grid construction scale, the upgrading of transmission current level and the innovation of current transmission technology, we are forced to pay close attention to the safety management of transmission projects, which is very important for social security and development. As an important part of the power grid, the stability and security of the transmission tower are closely related to the safe operation of the whole power grid. Therefore, the construction and maintenance of transmission towers need a set of scientific, quantitative and systematic safety evaluation methods. This paper will sort out the influencing factors that affect the safety of transmission towers, and then introduce a variety of mathematical models and methods to establish a perfect safety evaluation system.
UHPC-Annular Reinforcement Wet Joint Performance Analysis and Concrete Strength Influence Research
Authors: Zhang Jun , Qin Kaiqiang , Liu Jianhui , Ge Haifang
Published: June 2021

Based on the Shanghai Road High-speed Railway Station Connection Line Reconstruction Project in Suqian City, this paper firstly introduces the broad application and development prospects of prefabricated small and medium-span bridges, and explains the purpose of this paper; secondly, it introduces UHPC-ring steel bar wet, the structural form of the joint, and the elastoplastic analysis of it, and the comparison of the original plan and the UHPC-ring steel wet joint plan; finally, the law of the influence of the strength of the joint concrete on the wet joint performance is carried out. the study. The research results show that: UHPC-annular steel bar wet joint has good mechanical properties. As the strength of post-poured concrete at the joint increases, the ultimate bearing capacity of the structure, the bearing capacity of the steel bar when it yields, and the bearing capacity when cracking are all increased accordingly. The change in the bearing capacity corresponding to cracking is the most obvious, and the increase in the yield strength and ultimate bearing capacity of the steel bar is not very obvious.
Influence of Transmission Lines on Dynamic Characteristics of Transmission Tower
Authors: Hu Qilong , Zhang Heng , Chen Xudong
Published: June 2021

The influence of transmission lines on dynamic characteristics of transmission tower should not be ignored due to the heavy quality of transmission lines. The finite element models of independent tower and transmission tower-line system are established by ANSYS. The modal analysis is carried out to study the influence of transmission lines on dynamic characteristics of transmission tower. Meanwhile, it is verified by experimental modal analysis. Results show that, the tower-line coupling effect has a great influence on dynamic characteristics of transmission tower. The coupling effect strengthens the vibration intensity. In terms of frequencies, it mainly affects longitudinal bending mode and torsional mode frequencies of transmission tower, but has little effect on transverse bending mode frequency. Therefore, the influence of tower-line coupling effect must be considered in vibration reduction design of transmission tower-line system.
A comparable study on the deterioration of concrete under sodium sulfate and magnesium sulfate attack
Authors: Wu Jiang , Zhu Wen , Wei Jiangxiong , Tang Mengxiong , Zhang Shuo , Zhang Xianyuan
Published: June 2021

The deterioration mechanisms and corrosion of concrete exposed to Na2SO4 and MgSO4 solution were investigated in the present study. The damage of concrete specimen was evaluated by multi-scale observation, change of mass and relative dynamic modulus. Quantitatively analyse of the compositions for corrosion products during sulfate attack was applied in this study. The concrete was mainly cracked and spalling at the edges and corners when immersed in sodium sulfate solution. But pitting corrosion was formed on the surface of concrete under magnesium sulfate attack, and the powder peels off into a honeycomb hollow structure.
Start-up of Anammox and Effect of Fe2+ on Nitrogen Removal Rate
Authors: Wang Bing , Sun Bing , Liu Yunlong , Yang Lin
Published: June 2021

Anammox reaction was started by inoculating sewage plant digested sludge, and the change of N element in the reactor was detected. It was found that Anammox needed to go through three parts: hydrolysis period, activity lag period and activity increase period. The effect of different Fe2+ concentrations on the denitrification rate was investigated with the well-run Anammox sludge as the inoculation sludge. The results showed that Fe2+ had a positive effect on the anaerobic ammonium oxidation reaction within a certain concentration range, while the denitrification effect would be inhibited if the concentration was too high. When the concentration of Fe2+ was 0.08mmol/L, Fe2+ on Anammox had the best denitrification effect.
Performance analysis of steel slag powder-coal gangue grouting material
Authors: Lin Yuezhong , Wang Qingjiang , Wu Changsheng , Wang Chuanwei
Published: June 2021

In this paper, coal gangue soil, steel slag powder and polycarboxylic acid superplasticizer with different dosages were combined into ordinary Portland cement. Grouting solution was prepared according to different water-cement ratios and solidified under standard conditions. Through orthogonal experiments, the influence of different dosages on the rate of grout stones and the compressive strength of stones in different ages was studied. The experimental results show that the increase in the amount of coal gangue will lead to the decrease of the slurry stone first and then increase, and the compressive strength will decrease. The increase in the amount of steel slag powder reduces the stone rate and compressive strength of the slurry.
Research on Adaptive Power Transmission Line Fault Inspection
Authors: Wu Jian , Shao Shuang , Jiang Dongping , Yao Hongfang , Ma Caiguo , Xu Kekui
Published: June 2021

Power transmission line is one of the most important infrastructures of power system, and its safety monitoring is of great significance. The conventional way of fault monitoring of power transmission lines by only setting threshold value on single temperature data of strain clamp turned out to multiple misjudgements and delayed alarms, causing the increment of operation risk of power transmission line. In this paper, various types of time-varying sensors data such as strain clamp temperature data, environmental data, and cable ampacity data are accounted. Also, an unsupervised machine learning algorithm - K-means clustering algorithm was introduced to build a discriminant model in detecting the defects of power transmission line. Experimental results proved that the proposed method is able to avoid delayed alarms as well as misjudgement incurred from conventional method. As a result, the operation safety of power transmission line and inspection efficiency can be improved. The inspection cost would be reduced as well.
Parallel Efficiency Analysis of Large Increment Method Based on OpenMP
Authors: Hongxue J , Danbing L , Xila L
Published: June 2021

Large Increment Method (LIM) is a novel force-based method based on the generalized inverse matrix theory for solving material nonlinear problems in small deformation and small displacement conditions. For the spatial parallel computation, LIM can compute the constitutive equations of each element in parallel. By analyzing the parallel-calculating characteristics of LIM, the OpenMP is used for the parallel computation in spatial domain. Through the parallelism analysis of the spatial and time domain for LIM, it shows that LIM has an excellent parallel efficiency in space parallel computation.
Design of index and standard system of water-saving carriers in Jinhua City
Authors: Xu Haibo , Wang Yuehua
Published: June 2021

According to the needs of water-saving carrier construction and assessment in the process of national water-saving society innovation pilot in Jinhua City, the index system, construction standard and assessment method of water-saving carrier construction are analysed and studied. Combined with the water-saving demand of urban and rural life, this paper puts forward the evaluation mode of four construction carriers of Jinhua water-saving community, school, organ and institution, hospital, which provides support for the construction of water-saving society in Jinhua City.
Research on site selection of old campus bookstore based on the combination of space syntax and analytic hierarchy process——Take Huangjiahu Campus of Wuhan University of Science and Technology as an example
Authors: He Minghui , Xu Hong , Wang Rui , Chen JianJun , Liu SiWei , Li TianYue
Published: June 2021

The bookstore is an integral part of campus public service, and it is an essential place for reading, learning and spending for teachers and students. Provided the current management and development problems faced by old campus bookstores, this article takes the old campus bookstore in the Huangjiahu campus of Wuhan University of Science and Technology as a research case while uses space syntax theory, Depthmap software, and axis models to analyzes and evaluate accessibility, and then optimize campus old location and layout of bookstores. Simultaneously, by using the analytic hierarchy process, the simulated bookstore sites of selection in the campus are tested at the target level, decision level and plan level. This article aims to propose optimization methods for the management and development of old campus bookstores from the perspective of spatial location selection through qualitative quantification and provide constructive references for similar research.
Smart growth of historic district under the resilience and sustainability: A case study of Shuanglong Lane in Kaifeng
Authors: Huang L W , Wu Z W , Fan Y , He Y H
Published: June 2021

Historical blocks are rich in cultural relics and historic buildings, and their renewal and activation play an important role in improving the decline of the city center and enhancing the quality and taste of the city. Based on the concept of resilience and sustainability, combined with the regional characteristics, cultural background, and the actual situation in the renovation and renewal of Shuanglong Lane, this paper explores the smart growth strategy and practice of the historical district in the three-dimensional framework of the environment, business form, and society, through the integration of physical space, the reconstruction of commercial space and the harmony of social space. The purpose is to promote the same type of block in the process of protective renovation and characteristic rejuvenation, to resist disasters in the form of a complete community, and to improve resilience, adaptability, and sustainable development.
The Impact of Temporary Projects on the Ecological Environment and Their Corresponding Protection Measures in the Construction of Highways in Northern Tibet
Authors: Feng Zhiqiang , Xue Rongrong , Ge Liyan
Published: June 2021

In order to facilitate the construction of highway projects, temporary works are generally set up along the road. The temporary works of the highway project mainly include borrow yard, spoil yard, gravel stockyard, stone field, construction plant and construction road. The setting of temporary projects will cause damage to the surrounding ecological environment. Taking the Nala Highway as an example, this paper will analyze the ecological environment impact brought by the temporary construction in detail, and propose corresponding protection measures.
Analysis of the Impact of Fiscal Policy on the Innovation Performance of New Energy Vehicle Companies-An Empirical Analysis Based on Panel Data of Listed Companies
Authors: Hou Li , Liu Qin
Published: June 2021

Based on the panel data of listed companies in China’s new energy automobile industry from 2015 to 2019, an empirical test of the impact of government direct and indirect subsidies on corporate innovation performance is studied, and the mediating role of corporate innovation input is studied. The research results show that direct government subsidies have a positive impact on the innovation performance and investment of enterprises, and indirect government subsidies have a positive impact on the innovation performance and investment of enterprises. At the same time, corporate innovation investment plays an intermediary role in government subsidies and innovation performance. On the basis of the above conclusions, it provides a reference for the government to evaluate the effect of subsidies and adjust subsidy policies.
Application Of Characteristic Protection Of Historical And Cultural Blocks In Urban Renewal Through The Investigation And Research In Jinan By Taking Furong Street-Qushuiting Street As An Example
Authors: Sun Yue
Published: June 2021

Many historical and cultural blocks have faced challenges due to the acceleration of urban modernization in China, not only the aging of urban buildings and municipal infrastructure, but also transformation, construction and renewal of the urban have a large-scale impact on the historical and cultural blocks, the fundamental changes in the way of life and street function of the citizens put forward new requirements for the physical environment of spatial environment of historical and cultural blocks. The healthy and orderly development of the traditional scenes of historical and cultural blocks can bring different vitality and economic points for the development of the city. Taking urban renewal of Jinan and historical block protection as the discussion point, this paper discusses the present situation, characteristics and existing problems of Qushuiting Street and Furong Street from the space structure, historical context and humanistic characteristics, so as to explore the integration, inheritance and development of the artistic style and cultural connotation of traditional historical and cultural blocks in urban renewal.
Research on Outdoor Thermal Environment of Campus in Cold Area in Winter with Different Underlying Surfaces
Authors: Luo Wei , Hao Sheng , Wang Yuzhuo , Xu Zenan
Published: June 2021

Thermal environment has many influences on people who use outdoor space. The thermal environment of university campus is an important part of educational living space. In campus planning and design, the impact of landscape design on the thermal environment should be considered. This paper measures the thermal environment of the campus of Xi’an Eurasia University and conducts questionnaire survey to obtain the Library and Nanshan Road, East Gate Square and Parking lot 4 different underlying surface characteristics of the impact on the thermal environment. The results show that the SET* correlation of different underlying surfaces: Library> East Gate Square> Nanshan Road > Parking lot. Shade, grassland, and water bodies can effectively reduce the average radiant temperature. Among them, the humidification and cooling effects of the shade are the best, and the cooling ability of the grass is second only to the shade. In the process of campus environment design, reasonable adjustment of the relationship between the shade of the grass and other underlying surfaces can effectively improve the outdoor thermal comfort of the campus in winter and create a comfortable outdoor activity place on the campus.
Analysis on the Environmental Characteristics of Old Residential Areas in the North from the Perspective of Urban Renewal
Authors: Xian Ning , Chai Lin Xi
Published: June 2021

In the process of urbanization construction, we should not only consider the economic construction of the city, but also consider the environmental construction of the city, especially the environmental construction of some old residential areas. The purpose of this paper is to explore the environmental characteristics of the old residential areas in the north from the perspective of urban renewal, and to provide a theoretical basis for the environmental construction of the old residential areas in the north. Using operational research-based analytic hierarchy process (AHP) and statistical-based principal component analysis (PCA), the environmental characteristics of the old northern residential areas are established, the weights of each index are determined, and the environmental characteristics of the old northern residential areas are put forward from the perspective of urban renewal.
Research on Traffic Condition Discriminant Technology of Urban Intersections Under Intelligent Lighting System Based on Fuzzy Comprehensive Evaluation
Authors: Hao S Y , Zhao N L , Wu Y Z , Li J H , Wu K M , Jiao C W
Published: June 2021

Firstly, the basic traffic data collection methods based on intelligent lighting system are introduced, including RTMS data collection and video data collection. Then, based on the fuzzy comprehensive evaluation, a traffic condition discrimination model of urban intersections under the intelligent lighting system is established. The average speed, stop delay and queue length detected by the intelligent lamp post collection equipment are selected as evaluation factors, and the traffic status of signalized intersections is defined as smooth traffic, normal congestion and severe congestion. The research results have realized the fine discrimination of urban intersection traffic operating condition under the intelligent lighting system.
Simulation of storm surge and wave due to Typhoon Lekima in 2019
Authors: Yang Wankang , Yang Bin , Yang Qingying , Ou Jian , Xu Xuefeng
Published: June 2021

Zhejiang province is located at the southeast coast of China and vulnerable to typhoons generated in the northwest Pacific Ocean. An integrally coupled surge-wave model is developed and applied to the simulation of storm surge and wave induced by typhoon Lekima occurred in 2019. When considering wave-induced forces and using identical unstructured grid in coupled model, the model shows high accuracy and reproduces the typhoon process well. The distribution of maximum surge level shows great spatial differences along Zhejiang coast. Due to shelf geometry and shallow water effect, peak surge level rises significantly near Zhejiang coast. In addition, the peak surge levels on the right side of typhoon track are much higher than that on the left side. Contrary to characteristics of storm surge levels, significant wave height decreases rapidly near the Zhejiang coast due to shoaling, blocking of islands, and wave breaking.
Exploration on road maintenance of new infrastructure enabling intelligent expressway
Authors: Wu Honggang , Liu Xueying
Published: June 2021

During the 13th Five-Year Plan period, “new infrastructure” was written into the “Outline for the Construction of a Transport Power”, and the Ministry of Communications made it clear that intelligent maintenance was the focus of technological innovation. Taking Hangzhou-Shaozhou-Ningbo Expressway as an example, this paper discusses the contents of expressway road maintenance based on new infrastructure construction, and finds the following prominent problems: lack of unified industry standards; there are disadvantages in software assurance; insufficient interaction of elements; the level of regional integration is not high. By establishing the theoretical model of “MADD” and innovating the maintenance mobile terminal platform, the corresponding solutions and strategies are further proposed: strengthening the top-level design and establishing a unified standard; strengthen software matching and promote overall collaboration; strengthen the integration of construction and use, promote the interaction of elements; we will strengthen communication mechanisms and promote regional coordination. The result shows that the road maintenance of new infrastructure enabled expressway is of great significance. The research of this paper has certain reference significance for the further development of highway maintenance and construction in Zhejiang Province in the future.
Spatiotemporal Variations of NDVI in Xinjiang Tianchi Bogda Peak natural reserve from 1990 to 2015
Authors: Wu Jiaqi , Chen Liang , Fu Zhuo , Xiao RuLin , Wen Ruihong , Wang Xuefeng
Published: June 2021

The spatial characteristics of NDVI of Xinjiang Tianchi Bogda Peak natural reserve are analyzed by using the AVHRR and MODIS NDVI date from 1990 to 2015. The temporal change of NDVI of this natural reserve is analyzed by using one variable linear regression and the correlation analysis. The results indicate that, the NDVI values are higher in north than those in south in 2015. As the altitude increases, the NDVI first increases, and then decreases. According to the grading results, the proportion of the moderate vegetation grade is larger than others. From 1990 to 2015, the change rate of NDVI is 0.0171/5a (p > 0.05). The NDVI of this natural reserve shows an increasing tendency, except for 2005-2010. The results of this study provide a theoretical basis for the management department to fully understand the vegetation status in the natural reserve, and to make policies and measures accordingly.
Evolution of prototype basin and analysis of lithofacies paleogeography in Hongqi depression
Authors: Shen Wenjing , Peng Wei , Ma Guangyu
Published: June 2021

Based on the analysis of three-dimensional seismic data in Hongqi sag, it is clear that the structure of the depression is controlled by volcanic mechanism, controlled subsidence fault and secondary fault. The structure is complex. The structural framework of the residual basin changed greatly due to the multi-stage tectonic movements. It is not conducive to the understanding of the prototype and lithofacies paleogeography of the depression. Through the study of the recovery of the prototype basin in the key period, the basin prototype of different construction and transformation periods is constructed. The paleogeographic characteristics of lithofacies in different periods are determined. Then, combined with the analysis of single well facies, lake water advance and retreat and sediment supply conditions, the lithofacies paleogeographic characteristics of different periods are determined. The sedimentary period of Tamulangou formation developed a lithofacies paleogeographic pattern of coexistence of volcanic rocks, fan delta and lakes. During the sedimentary period of Tongbomiao formation, the lake basin develops. But the water body is shallow. The material source is sufficient. The fan delta shallow lake sedimentary assemblage is developed. During the deposition period of Nantun formation, the lake basin further expanded rapidly. The water body became deeper. The lake basin became larger. The fan delta shrank. It is fan delta lacustrine sedimentary assemblage. The sedimentary period of Damoguaihe - Yimin formation is a fan delta lacustrine sedimentary assemblage dominated by lacustrine deposits.
Experimental Study on Crack Characteristics of Damaged Reinforced Concrete Beams strengthened with CFRP
Authors: Huang Junhao , Qian Yongjiu , Yang Huaping , Li Jing , Pan Xingwei
Published: June 2021

The bending tests of 2 control beams and 6 damaged beams strengthened with CFRP (DBSC) were carried out to study the effects of adhesive layer thickness, number of CFRP layers and reinforcement ratio on crack characteristics of DBSC. The test results show that the crack development of the DBSC is accelerated and the crack resistance of the DBSC is reduced compared with the intact beam. With the increase of the thickness of the adhesive layer, the crack development of the DBSC is slowed down and the crack resistance is improved. Increasing the number of CFRP layers is helpful to restrain the crack development of DBSC under high load level. The increase of reinforcement ratio can significantly improve the crack resistance of DBSC.
Research on detection technology of squeezed branch and disk pile under boulder geological condition
Authors: Zhu Wen-Tong , Guan Wei-Dong , Li Hai-Qin , Qiu Xu-Fu
Published: June 2021

The detection methods of the cavity and cavity size and pile quality of squeezed branch and disk pile are not perfect. Based on the 65 pier of a viaduct in Zhongshan City, this paper uses caliper, cross hole acoustic wave method, core pulling method and tube wave method to detect the squeezed branch and disk pile, and compares and analyzes the advantages and disadvantages, applicable conditions and detection results of each method. It can be seen from the test results that both caliper and cross hole acoustic wave method can detect the length of squeezed branch pile, while core pulling method and tube wave method can detect the quality of pile body and the thickness of sediment at the bottom of pile. The test results are basically consistent and verified with each other, and the specific data such as the length of branch and the thickness of sediment are slightly different. In this paper, caliper, cross hole acoustic method, core pulling method and tube wave method are verified and analyzed to provide ideas and support for the later detection of squeezed branch and disk pile.
Flexural behavior analysis on RC simply supported girder strengthened by adding diagonal brace
Authors: Mao Dejun , Du Yanbin , Zhang Zongxing , Chen Xu , Yu Wenzheng
Published: June 2021

Adding the diagonal bracing to strengthen RC simply supported beam bridge has certain engineering application space. In order to study the flexural performance of the strengthened members, the finite element model was established by Midas/Civil to calculate and analyze the load effect of 20m span RC simply-supported T beam under 12 flexural strengthening conditions. The results showed that the connection form of diagonal brace has little influence on the deformation behavior of the strengthened beam. After reinforcement, the positive moment and deflection of mid-span of the main beam can be reduced by more than 50%. At the same time, the main beam appears negative moment, horizontal reaction force, and vertical negative reaction force may occur. The reasonable arrangement of the brace position can ensure that the main beam does not have vertical negative reaction force, and the main beam negative moment and horizontal reaction force, the horizontal and vertical reaction force of the diagonal brace are controlled to obtain ideal load effect results.
Earthquake loss analysis and assessment of group buildings in Songyuan area
Authors: Wang Haoming , Su Siqing , Jia Huizhu
Published: June 2021

To study the earthquake damage and loss of group buildings in towns and urban areas of Songyuan, the simulation analysis of earthquake damage of group buildings in some areas of Chaganhua town and urban areas of Songyuan was conducted. In this paper, based on the building performance evaluation method in FEMA-P58 and the Standard for seismic resilience assessment of buildings (GB/T 38591-2020), the different methods between China and the US were eliminated. Firstly, the distribution of earthquake damage of various buildings was analyzed. The economic losses of the two regions are analyzed and compared by using PACT software to evaluate the repair costs and repair time of buildings under different earthquake levels.
Research and Analysis of Civil Airport Asphalt Concrete Pavement Damage Cause Evaluation and Countermeasure
Authors: Su J , Xiao F , Liu Z , Kong L , Wang P , Li B
Published: June 2021

Asphalt concrete pavement is characterized by convenient construction and maintenance, ride comfort, low noise, and strong adaptation and coordination deformation. Therefore, it has been gradually used in civil aviation transport airport runway, especially in recent years, the proportion of runways used in large hub airports has increased. However, asphalt concrete pavement also has many issues that is not conducive to the security of airport operation and management under the influence of traffic load, natural environment, and material performance. This paper analyzes and studies the causes and countermeasures of the damages through the investigation of several cases of asphalt concrete pavement damages in China, so as to provide reference for the extensive application and maintenance management of asphalt concrete pavement in airports in the future.
Analysis of Optimal Internal Water Pressure During The Operation Period of Ultra-long Water Tunnel
Authors: Zhu Qunyan , Dai Chunhua , Zheng Hanzhong
Published: June 2021

At present, the per capita shortage and imbalance of water resources are the basic national conditions of China, water-conveyance tunnel can solve some this problems. Because the tunnel project is a covert project, people cannot accurately know the operation of the project in advance, and can only basically know the operation state of the tunnel through the existing test means, thus bringing certain blindness to the tunnel operation management. This paper takes the Qiandao Lake Water Distribution Projec as an example, the stability of surrounding rock under different internal water pressure is analyzed and studied by using numerical simulation, and an optimal internal water pressure is obtained, which provides some guidance and suggestions for tunnel operation management and ensures the security of operation.[1][2][3][4][5]
Spatio-temporal distribution and correlation analysis of river water quality in City Center of Pinghu
Authors: Lei Yu
Published: June 2021

Based on the historical data of river water quality in the central city of Pinghu from 2014 to 2018, the temporal and spatial distribution of river water quality changes and its influencing factors were analyzed, and the correlation between the main monitoring factors was identified by linear regression. The results show that water quality of the main rivers has improved significantly, and the concentrations of COD, NH3-N and TP in most rivers can reach the class III standard of surface water. In recent years, the water quality of the rivers shows a significant improvement trend, and the improvement effect of NH3-N concentration is the most obvious. The water quality of general rivers tends to improve, but the effect of treatment is relatively insufficient. Spatially, the water quality in the northern part of the flood control area is worse than that in other areas, and the main river is better than the general river. The fitting effect of COD, NH3-N and TP is good, and there is a significant correlation between the main river.
Analysis of the stability of the construction phase of rigidly constructed bridge based on pile-earth effect
Authors: Zhu Qinghua , Tian Zhongchu
Published: June 2021

In the rapidly emerging Yunnan-Guizhou-Sichuan region, high-pier and long-span bridges are mostly high-pier and long-span continuous rigid-frame bridges over 100 meters, and the stability of their high-piers becomes more and more important. In order to study the stability of the structure under the action of pile-soil, the Wugong Bridge in Guizhou was used as a supporting project, and a large-scale finite element software was used to establish a construction model considering the effect of pile-soil. The influence of this type of bridge on the linear elastic stability of the structure under the action of pile-soil and the geometric nonlinear stability after considering the deflection of the structure is compared and analyzed.
Optimization of Suspender Tension Scheme of Cast-in-Situ Tied Arch Bridge with Support
Authors: Hao Yang
Published: June 2021

The suspender tension sequence and construction cable force of tied arch bridges have a greater impact on the internal force and deformation of the structure. In order to obtain a reasonable suspender tension plan, make sure that the internal force of the structure meets the specific requirements and is evenly distributed during the construction process to avoid the excessive internal force mutation, seven suspender tension schemes were proposed. Combined with the example of a half-through concrete-filled steel tube tied arch bridge project, this scheme introduces the “kurtosis coefficient” evaluation index, and compares and analyzes the changes in the internal force of the structure under different suspender tension schemes. In this paper, the pros and cons of each scheme/part were also discussed. The results show that the difference between the internal force of the bridge and the cable force during the bridge completion stage of each scheme is relatively small, which has a greater impact on the internal force of the bridge during the construction phase. Among them, the symmetrical sequential tension scheme is convenient for construction, but the local position (such as arch foot, arch top, 1/4 arch rib) the internal force changes obviously, and there will be a large peak value, which will affect the safety of the structure during the construction process; the symmetrical interval tension plan can improve the structural force condition and reduce the internal force peak value, but the overall trend is basically unchanged; the internal force distribution of the symmetrical alternating tensioning scheme is uniform, without major sudden changes, and no obvious peaks, so that the safety of the bridge construction process is more guaranteed.
Research on glacier DEM extraction method based on ASTER Data
Authors: Zhang Yashuang , Wu Haiman , Liu Deli
Published: June 2021

The greenhouse effect has led to a large area shrinkage of glaciers in the west of China, resulting in great changes in glacial landforms. In this paper, we use remote sensing satellite to obtain timely and accurate DEM, and use remote sensing technology to process DEM effectively, so as to obtain high-precision results, which can be used as the basic model to study glacier area change. In this paper, the DEM of Malan ice cap in Xinqingfeng is extracted from the orthoengine module of PCI, and the results of DEM obtained are compared with the reference DEM by using aster stereo image pair, and the results of Aster meeting the accuracy requirements are analyzed, which is helpful for the application of Aster stereo image pair in DEM production process.
Study on Time-Space effect and earth berm of foundation pit
Authors: Ruifang Wang , Luolan  , Juhua Pi
Published: June 2021

Excavation to the bottom of the pit after the expiry date, due to time-space effect, the shear strengths of soil are decrease, which produce safe hidden trouble. The mechanism of supporting structure and backfill of earth berm is analyzed in the paper. Combined with a commercial and residential complex foundation pit in Wuhan as the engineering background, according to the shear strength index of the soil after the foundation pit is retrieved from the foundation pit monitoring data after placing, the safety of the foundation pit is calculated. Calculated by finite element software, The stability coefficient of foundation pit decreases and the horizontal displacement exceeds the allowable value in the code if no action is taken after placing. After reasonable slope top width and slope ratio were adopted to backpressure backfill of the pit, the construction of residential property adjacent to commercial plot should continue until completion. The foundation pit monitoring data are normal during the time, which indicated that the bottom earth berm with back pressure can reduce the horizontal deformation and increased stability of the foundation pit, this method can provide some reference for similar foundation pit treatment.
Failure mechanism of subway structure with different central columns based on Daikai Station
Authors: Wu Fengyuan , Xu Huaiyu , Liu Tong , Wang Qinghe
Published: June 2021

The central columns of the Daikai Station in Kobe City were severely damaged due to Hanshin earthquake in the year 1995, leading to serious ground collapse. To evaluate the behavior of underground structures, the finite element model of Daikai Station was established using ABAQUS, and benchmarked against the measured data. Furthermore, the central column was replaced by concrete-filled steel tube (CFST) column to illustrate the response under the earthquake action. Results show that the central column of the station is one weak part of structure. Compared with the ordinary reinforced concrete (RC) structures, using CFST central column can enhance the overall rigidity of the structure and greatly improve the seismic performance of the underground structures.
The Expansive Soil Landslide Investigation and Administration of an Expressway
Authors: Zhao Tian
Published: June 2021

By exploring the expansive soil landslide of an expressway, this article analyzes the geologic characteristics and sliding mechanism of the landslide, and offers comprehensive measures. It accumulates experience for the other analogous areas for highway construction, and has certain reference significance.
Fire evacuation in complex underground space of personnel
Authors: Liu Jiaxi , Zhang Rui , Sun Li , Yan Weidong
Published: June 2021

As the consequences of building fire evacuation continue to be severe, some experts and scholars have proposed to combine building information modeling (BIM) technology with geographic information system (GIS) technology to construct a three-dimensional space scene of building fire evacuation. BIM has the advantages of refined three-dimensional modeling, and with the help of evacuation software, people evacuation and its characteristics are simulated, GIS has powerful spatial analysis functions to analyze the path. In this kind of evacuation simulation method, the two technologies complement each other to achieve quantitative analysis of qualitative indicators and efficient visualization of evacuation emergency management. This paper summarizes and analyzes the research on personnel evacuation in recent years by summarizing the current research situation in China, and puts forward the existing problems, hoping to provide ideas for the further research.
Simulation of interception capacity of Nanhe initial rain storage tanks
Authors: Wang Ziming , Gao Jian , Du Zhijun , Zhang Ye , Lai Xijun
Published: June 2021

River pollution sources are generally divided into point source, non-point source and internal source, non-point source pollution is mainly urban surface runoff. In this paper, the non-point source pollution model of SWMM in Nanhe region is constructed, and the water quantity and quality are verified by the measured data, and the verification results are in good agreement with the measured data. On this basis, the detention time and the interception amount of initial rain are analyzed. The results show that after intercepting the initial rainwater, the pollutants into the river are significantly reduced, and the lower the frequency is, the better the interception effect of the storage tank on the initial rainwater is. Comprehensive analysis shows that the overall removal rate of pollutants in each frequency of the four outlets of the storage tank can reach 37~39%.
Investigating the impact of Xuanmen Project on water residence time in the Yueqing Bay
Authors: Li Xinwen , Ying Chao , Liu Yong , Yao Wenwei
Published: June 2021

A 2D numerical model was used to investigate the impact of Xuanmen Project on water residence time in Yueqing Bay. Three model scenarios were designed to calculate the residence time. The WRT of CASE00 was obviously smaller than that of CASE01 and CASE02. While the WRT of CASE01 and CASE02 was relatively comparable. As for the individual scenario, the WRT increased from the bay month to the bay head. In CASE00, The average WRT of the outer bay, middle bay and inner bay was 21.6, 38.5 and 50.6 days, respectively. The average WRT of the entire bay was 32.7 days. In CASE01, a significant increase of WRT was observed in the entire bay. The average WRT of the entire bay was 46.1 days. The WRT increased about 10 days in the lower bay and 20 days in the northern bay compared to CASE00, indicating a significant impact of the Xuanmen Dam. In CASE02, the average WRT of the entire bay was 48.2 days. The WRT increased less than 5 days compared to CASE01, implying that the land reclamation had a minor impact on the WRT of the Yueqing bay. The flushing homogeneity curve (FHC) was used to study the spatial characteristic of flushing. The steepest curve occurred in CASE00 and the flattest curve occurred in CASE02, implying an increased inhomogeneity due to Xuanmen Project.
Model tests and theoretical analysis of the vertical vibration of a single pile in saturated sandy soil
Authors: Li X Y , Li Q , Hu L , Huang L Q
Published: June 2021

The study of vibration dynamic response of pile foundation has critical applications for seismic structure design. In this paper, firstly, the vibration characteristics of single pile with different length to diameter ratios under different vibration frequency loads were studied by the foundation pile model test method. Moreover, the amplitude-frequency curves of single pile vibration are plotted by using Fourier transform. Then the theoretical model of the pile-soil-cap system under sinusoidal periodic vibration load is established by using saturated porous medium theory, and the amplitude and frequency curves are obtained. Numerical results show that the theoretical solution can be in good agreement with the experimental results, which verifies the validation of the theoretical model. Furthermore, the resonant frequency is proven to be negatively related to the length to diameter ratio of the pile under the same pile diameter.
Application of BIM technology in prefabricated buildings
Authors: Liu Jingjing , Zou Zuxu
Published: June 2021

Based on the disadvantages of the current traditional construction mode, this paper analyzes the status quo of the gradual disappearance of demographic dividend and discusses the necessity of developing prefabricated buildings. This paper elaborates the advantages of applying BIM technology to prefabricated buildings in theory. Finally, the application of BIM technology in prefabricated buildings is demonstrated by introducing the construction process of a prefabricated community project. Through the example demonstration, it can be seen that BIM technology integrates all the information of the construction project, which can not only standardize the construction site and make the structural design more efficient, but also provide an efficient platform for communication among various parties. This exploration plays a positive role in promoting the popularization and development of prefabricated buildings.
Undrained solution of cylindrical cavity expansion for unsaturated soils with modified Cam-clay model
Authors: Zhai Zhanghui , Ma Shengjun , Zhang Yaguo , Zhang Changliang
Published: June 2021

This paper develops a new semi-analytical approach for undrained cylindrical cavity expansions in unsaturated soils. The unsaturated soil behavior is described within a simple, yet effective, critical state-based elastoplastic framework with suction being treated as a hardening parameter. Different from its saturated counterpart, the cavity expansion problem in unsaturated soils involves five basic variables, namely, the three stress components, specific volume, and suction. A constitutive equation for the water phase, in addition to the soil elastoplastic constitutive relationship plus the radial equilibrium condition, is therefore required to construct a set of coupled, self-contained differential equations for the solution of the cavity boundary value problem. With the introduction of an auxiliary variable, all these governing equations can be expressed in terms of the Lagrangian formulation and then simultaneously solved through the standard numerical procedure. The numerical example results show that the suction has significant hardening effects on the overall cavity expansion responses and, in particular, the stress trajectories calculated for a representative soil element at the cavity surface. It is also interesting to observe that the shear dilation phenomenon, developed during the course of cavity expansion, usually occurs in relatively dense unsaturated soils with high unsaturated suction.
Electrical design of 4×50MW small thermal power plant
Authors: Feng X J , Luo J
Published: June 2021

The paper is the primary and secondary electrical design of a 4×50MW small-scale power plant. We selected the number and type of main transformers of our factory, plan to design two alternatives for main electrical wiring. The equivalent circuit diagram is simplified, and each short-circuit point is calculated in order to provide data protection for the subsequent selection, and then combined with the calculation results of each short-circuit point to select and verify the types of various equipment in the power plant.