bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Design Method of Axial Compressive Capacity of Circular CFST Slender Columns
Authors: Gao Pan , Yang Chang , Yu Zhixiang
Published: March 2020

With the emergence of large-span spatial structures and high-rise buildings, circular concrete filled steel tubular (CFST) slender columns are necessary to be used in practical projects. In order to discuss the calculation method of the axial compressive strength of circular CFST long columns, especially slender columns, three codes of EC4, AISC and AIJ are compared and analysed based on the existing experimental data of 105 long columns collected from previous literatures. It is found that EC4 and AIJ can provide accurate prediction for long columns with length-diameter (L/D) ratio less than 20, and EC4 is more stable. However, for slender columns when L/D ratio is greater than 20, the deviations of the calculated values of these three codes lose guidance. Furthermore, it is found that the deviation between the calculated and measured values of EC4 performs a power function with L/D ratio. Therefore, based on the calculation formula of EC4, a revised coefficient of L/D ratio is proposed, so that the revised formula can accurately predict the axial compressive capacity of slender columns without affecting the prediction of short columns.
Study on Static Elastoplastic Analysis of a High-Rise Frame-Shear Wall Structure
Authors: Zhang Xu , Sheng Fan , Ma Jianqiang
Published: March 2020

Static elastoplastic analysis is a widely used method to evaluate the seismic performance of structures. The project example in this paper is the high-rise frame-shear wall structure of the second phase (Yongsheng homeland) of the Baisha resettlement area in Zhengdong New Area. The three-dimensional integral model is used to calculate the force of the building under earthquake using the static elasto-plastic analysis method. Analysis was conducted to obtain the stress conditions of high-rise buildings against plastic deformation, and the sequence of the plastic hinges, and the unfavorable floors of the high-rise structure were identified, which provided guidance for the design of such structures.
Study on Geological Structure and Gas Content Occurrence Regularity of Gas Mine
Authors: He Jiangyi , Lei Wulin , Zheng Chao
Published: March 2020

This paper systematically analyzes the distribution characteristics of geological structure of high gas mine, discusses the influence of geological structure on coal seam gas deposit, and obtains the distribution law of gas in the mine. The relationship between the original gas content of coal seam and the factors such as elevation of bottom plate, depth of coal seam and thickness of overlying bedrock is established. Then effectively guide the coal mine gas management, for the mine coal bed gas reserve budget and gas extraction standard effect evaluation provides a reference.
Seismic Vulnerability Analysis of High-Rise Composite Frame Concrete Tube Composite Structure
Authors: Zhang Shuyun , Zhou Jie , Hao Yonglei
Published: March 2020

In order to study the possibility of structural failure of high-rise composite frame-concrete tube structure under different earthquake intensity, seismic vulnerability analysis of the structure is carried out based on IDA principle, and its seismic performance is evaluated. Taking 30-storey high-mixing structure as an example, eight seismic records are selected. After amplitude modulation, non-linear dynamic time history analysis is carried out. PGA, PGV and Sa are selected as seismic intensity parameters, and the maximum inter-storey displacement angle is selected as structural performance index. IDA curve clusters are obtained. Quantile curve method is used to analyze and analyze the results. It is concluded that PGA strength index is more effective. The seismic performance of this kind of structure is evaluated effectively, and then the vulnerability curve and vulnerability matrix are obtained. The analysis results show that the hybrid structure can meet the requirements of “three-level” seismic response and has good seismic performance under 8-degree frequent, basic and rare earthquakes.
Computational Analysis of Damping Devices in Mitigating Seismic Response of a Concrete Structure
Authors: Fan Xuefeng , Wang Shijun
Published: March 2020

In the area of earthquake, it is essential for structures to survive to mitigate their seismic responses. And among the most common strategies, the application of damping devices is of significant feasibility for its unarguable effects and being extremely straightforward. Dampers always work following an identical physical rule, however, difference in their position and shapes can enlarge the disparity in effects. To explore the difference, this research analysed the effect of damping devices installed in a particular concrete structure, where dampers are in different shapes but close in cost. The Finite element modelling technology is applied in simulation of the seismic response of concrete structure equipped with the dampers. According to the comparison of effects for different dampers, this research provided a reasonable suggestion for choosing damping devices.
Impact of the Fire Propagation on the Residual State of the Peripherally Supported Grid Structure
Authors: Tang Gan , Shi Renyi , Li Zhanjie , Yin Lingfeng , Li Weiwei
Published: March 2020

The objective of this paper is to computationally investigate the structural residual states of the peripherally supported grid structure under different fire propagation paths and reveal the path impact on the structure. The results demonstrate that the fire propagation path has a significant impact on the residual deformation of the grid structure while it has negligible impact on the distribution of residual axial member force. Hence, the structural residual states are quite different of different fire propagation paths.
Seismic Performance of Buckling Restrained Braced Steel Frames Considering BRB Connection
Authors: Jia Mingming , Liu Kai , Hong Cheng , Brwa Ahmed Saed
Published: March 2020

Previous studies of BRBF showed that there are two main requirements to reach the desired mechanical behaviour of buckling restrained braced frames (BRBF) under seismic loadings. This behaviour could be represented by sufficient plastic deformation and ductility capability of core plate member. 1) The first requirement is to prevent overall buckling of BRB; and 2) the second requirement is to prevent out-of-plane buckling of gusset plates. This study focuses on the second main requirement through presenting finite element analysis results of several proposed gusset plates and two joint sections for connecting core plate member with gusset plate. Further, study the impact of proposed gusset plates and joint sections on behaviour of steel frames. The pushover analysis that performed in this study is followed the method that discussed in AISC-2010 Seismic Provision manual. Therefore, the proposed connection of buckling restrained braced steel frame required to sustain cyclic loadings start with elastic drift up to two times of design drift. The analysis results showed that the proposed connections sufficiently sustain all the axial force from BRB without out-of-plane buckling occurs or losing the stable hysteretic response of the BRB, finding that the equal dimensions of gusset plate vertical length and horizontal length has much better effect on frame.
Controlling Measure for Distortional Buckling of Cold-formed Thin-walled Steel Lipped Channel Members
Authors: Yao Xingyou , Yin Jiawen , Hu Pengwen , Song Xiaoqing , Li Xiao
Published: March 2020

This paper proposed a structural measure according to add batten sheets between two lips to controlling distortional buckling of cold-formed thin-walled steel members with lipped channel section, and the effectiveness was verified through existing tests. At the same time, the stiffness requirements of batten sheets were presented. The structural measures of adding batten sheets between two lips can effectively prevent the rotation of partially stiffened elements, and the distortional buckling load and bearing capacity of the members have been greatly improved. The test shows that the batten sheets with a certain distance and stiffness can improve the bearing capacity of the member or avoid the occurrence of distortional buckling.
Structural Rationality Research on Integrated Prefabricated I-Shaped Steel-Concrete Composite Girder Bridges
Authors: Peng Bo , Peng Rongrong , Su Huanghe , Lu Zhiwei
Published: March 2020

In order to promote the use of steel-concrete composite bridges in small and medium span bridges, and improve industrial construction of bridge and assembling degree of the composite girder bridge, an integrated prefabricated steel-concrete composite girder bridge was proposed. Considering the requirements of small and medium span bridges and the condition of highway transportation, the basic unit of the integrated prefabricated steel-concrete composite girder was constructed, and the connection way of units was put forward so as to further form the whole bridge. According to the result of calculation and analysis, the mechanical behaviour of the integrated prefabricated steel-concrete composite girder is superior to the traditional separated prefabricated steel-concrete composite girder, and it also performs better than the existing prefabricated concrete box girder and prefabricated concrete T-shaped girder in economy from the prospective of cycle. Besides, by comparing with the existing prefabricated concrete box girder, the prefabricated concrete T-shaped girder and the separated prefabricated steel-concrete composite girder, the integrated prefabricated steel-concrete composite girder would significantly improve the construction efficiency and shorten the construction period, and the construction quality could be guaranteed. All in all, the integrated prefabricated steel-concrete composite girder is a rational structure with convenient construction for bridge engineering.
Design and Verification Test of Quasi-Static Pushover Model Container
Authors: Xu Kunpeng , Jing Liping , Bin Jia
Published: March 2020

Laboratorial testing methods for exploring seismic response mechanism of underground structures usually consist of conventional shaking table test and centrifuge shaking table test. The types of model containers employed to investigate the seismic response mechanism of underground structures during dynamic tests include rigid, flexible and laminar shear model containers, all of them have some drawbacks. It is essential to choose an appropriate model container in terms of test requirement, according to the quasi-static pushover testing method a novel model container was proposed. A set of quasi-static pushover tests were conducted to verify the performance of the new container. The experimental results show that the designed model container can effectively simulate the most unfavourable deformation mode of invert triangle in push direction, which means that quasi-static testing method with this model container can be applied to evaluate seismic response of underground structures, furthermore, the deep-buried condition is also can be simulated.
Comparative Optimization and Application of Rectification Schemes for Shear Wall Structure
Authors: Li Shuai , Li Yanhe , Lu Yi
Published: March 2020

For the lift correction design of the shear wall structure, there are two schemes to choose the new underpinning structure jacking and the direct jacking under the wall. Combined with a practical project, this paper puts forward the way of opening jacking joint mainly, supplemented by underpinning structure jacking, and points out that the new underpinning structure jacking method should be designed and checked according to the space truss theory. Direct jacking with holes under the wall should meet the requirements of jacking bearing capacity, local bearing capacity and axial pressure ratio. Through the comparative analysis of the two schemes, it is considered that the opening direct jacking method should be given priority, so as to provide reference for similar projects.
Effects of Bottom Obstacle Structure on Density-Induced Flow
Authors: Huang Shuo , Huang Wenrui , Shen Qi
Published: March 2020

Density flows frequently occur in nature and some of them have caused serious consequences, such as sedimentation and saline water intrusion. In order to control density flows, the method like placing an obstacle has been proposed. In this paper, the influence of the height and position of obstacle and the salinity difference on the behaviors of lock-exchange density flow was studied experimentally by using high-speed camera and laser particle image velocimetry (PIV) technique. The experiments were conducted in a plexiglass flume whose height, width and depth were 1.8 m, 0.22 m and 0.3 m respectively. Besides, the bottom of the flume is smooth. The flume was separated by one board and the left side of the flume was filled by fresh water while the right side of the flume was filled by salt water. After the board was lifted, the salt water flow into the fresh water and formed a density flow. Obstacles were placed 0.05 m and 0.25 m away from the gate respectively. The velocity and flow field were measured by using the PIV technique. The results indicated that the existence of obstacles blocked the progress of density flow and the propagation distance of density current in the case without obstacle was much longer than the other one which contained obstacle. Additionally, it was observed that when the density flow was crossing over one obstacle, a re-acceleration process was happening at the head of the current, and the maximum velocity caused by this process was larger than the maximum velocity without obstacles. Besides, by comparing the obstacle and non-obstacle situations, the body velocity of density flow was greatly reduced at the front of obstacle. However, the effect of different obstacle positions on the maximum velocity of the head of density flow is not significant.
Analysis on the Static Performance of a New Type of Large-Span Fabricated Grid-Plate Ribbed Composite Floor Structure
Authors: Liu Kai , Zhao Xueying , Wu Xuewen , Yi Shuai , Zhou Yan
Published: March 2020

A new type of large-span fabricated grid-plate ribbed composite floor structure is proposed basis on fabricated steel-concrete composite structure. The new structure consists of four sides of rib, bottom slab and internal concrete block. In this paper, the static performance of the new structure is analysed by the finite element method and compared with the combined open-web sandwich plate structure. The analysis results show that the new type floor can reach 1/30-1/35 of the span. Under the same span, mesh size and load, compared with the existing combined open-web sandwich plate floor, the new type floor has large stiffness, small structure height, light weight, and reduce concrete and steel consumption by 77.6% and 7.3%, respectively. The structure is safe, reliable and has good economic benefits.
Application of 3D Laser Scan Technology in the Surveying and Mapping of Ancient Buildings
Authors: Xu Feijin , Chen Shuokui
Published: March 2020

Taking Wang’s ancestral temple in Yongshan Town, Leping City, Jiangxi Province as the research object, through the teaching practice of surveying and mapping of ancient buildings, this paper summarizes the advantages and disadvantages of 3D laser scan technology in surveying and mapping of ancient buildings and discusses the Methods and approaches of combining industry-university-research cooperation mode in local colleges and universities under the background of cultural relics protection.
Finite Element Analysis of Dynamic Time History of Steel Frame Structure Filled with Rubber Brick
Authors: Wang Fengchi , Ma Yifang , Liu Keyi
Published: March 2020

Studying the influence of rubber brick infilled wall on the seismic performance of steel frame has theoretical and practical significance for the use of materials in civil engineering industry. The modal analysis of SF, RSF, LSF, R1SF and R2SF, and the nonlinear dynamic time history analysis under the action of two actual seismic waves and one artificial seismic wave are carried out by using the large finite element analysis software ABAQUS. Based on the comparison of the infilled wall materials and the layout of the infilled wall, the influence of the structural frequency and the maximum horizontal displacement is analysed. The structure of the study indicates that: under the action of seismic waves, the natural vibration frequency of the whole structure is reduced by adding the rubber brick infilled wall, and the increasing speed of the natural vibration frequency of the whole structure is slowed down. Under monotonic and low-cycle reciprocating loads, rubber brick filled walls can effectively improve the bearing capacity and lateral stiffness of the whole structure, improve the stress concentration of frame columns, but weaken the energy dissipation capacity of the whole structure.
An Acoustic Discrimination Method for Impact Load Based on Artificial Neural Network
Authors: Wang Zhenhan , Ma Li , Zhan Qianru , Li Qinghua , Li Fuguo
Published: March 2020

In order to meet the engineering requirements of non-contact measurement of impact load and realize the intelligent identification of its characteristic parameters, this paper attempts to establish a method to analyze and learn the audio characteristics generated by accidental loads, such as impact and explosion, and to identify the impact load characteristics in reverse. The method, which is based on energy conservation, momentum conservation and strokes law, used p-norm in mathematics to extract the basic characteristics of impact load, and the frequency analysis to find the inevitable connection between the audio characteristics impulse-induced and the impact load characteristics. At last, “Acoustic Discrimination for Impact Load Identification (ADII)” by adopting the functions of artificial neural networks about learning, categorization and generalization was implemented.
Effect of Depressurized Hydrate on Soil Layer Around Wellhead
Authors: Yang Lele , Wang Jing
Published: March 2020

Nature gas hydrate has a wide distribution on land and in the sea, which can greatly meet human demand for energy and is a potential clean energy. This paper mainly studies the deformation of the soil around the wellhead during the process of exploiting hydrate by the anti-pressure method, and analyzes the two sensitivities of the dip angle of the hydrate-bearing soil layer and the decomposition range of the hydrate. This paper also evaluates the stability of the soil layer around the wellhead during exploiting. The study found that when the dip angle of the seabed soil layer is constant, the decomposition area and the deformation of the soil body increases continuously. When the decomposition range is less than a certain critical value, the deformation is limited and no collapse occurs; but once this critical value is exceeded, the soil around the decomposition zone is shear-damaged. The extent to which hydrate decompose has the greatest impact on soil deformation. These conclusions have certain reference value for the assessment of the safety of hydrate exploiting.
Coupled On-Site Measurement/CFD Based Approach for Wind Resource Assessment and Wind Farm Micro-Siting Over Complex Terrain
Authors: Hu Weicheng , Yang Qingshan , Zhang Jian , Hu Jianxiao
Published: March 2020

Wind resource assessment and wind farm micro-siting over complex terrain are essential for wind power management and wind farm operation. A coupled approach is presented for wind resource assessment over a complex topography in Changsha, China, and an improved Genetic Algorithm (GA) is introduced for optimization of wind turbines micro-siting. The Computational Fluid Dynamics (CFD) with Realizable k-ε turbulence closure is adopted to simulate the atmospheric boundary layer flow over the complex terrain, and the results are validated by the wind tunnel tests. Long-term on-site measurements from a meteorological station are combined with the CFD results to evaluate the wind energy potential over the complex terrain. A semi-analytical approach is proposed for prediction of yearly wind power generation at the turbine site, and the Jensen-Katic model is utilized in consideration of the wake effects. The improved GA is presented based on the wind resource map. The schemes with different grid discretization are studied. The results showed that the proposed approach is effective for wind resource assessment and wind turbines micro-siting.
Study on Longer Span Length of Hanging Tubular Busbar in 750kV Substation
Authors: Jia Yunhui , Li Yiping , Chen Kai , Liu Qiang , Zu Jinlong , Wang Huijun , Ren Pengfei , Zhang Xu
Published: March 2020

Based on mechanics study of 750kV hanging tubular busbar applied in Qiaowan 750kV substation, develop a new type of tubular busbar fittings, which is made of proper conductor material and tested in real model experiment. By using these fittings, longer span length of 750kV hanging tubular busbar can be applied in 750kV electric power distribution device and the deflection can be controlled in a narrow range of 0.5-1 times of tubular busbar diameter.
Research on Vegetation Community Restoration Technology of Engineering Destruction Surface Based on Real-Time Fusion of Environmental Background
Authors: Luo Wen , Ma Dongliang , Yang Dafeng
Published: March 2020

Vegetation community restoration is an important means for background matching modelling of destructive surface in disturbed area of engineering and real-time fusion of environmental background. Aiming at the problems of large-scale reconstruction or new construction, changing topography and landform, difficult ecological restoration and poor natural similarity of existing vegetation restoration. Through investigation of plant communities around the engineering area, methods such as stable base materials, rapid and sustained nutrient supply, plant screening and cultivation and functional testing were adopted. Three-dimensional construction of plant communities on the destructive surface of engineering disturbance area was carried out, promoting the succession of vegetation communities to surrounding vegetation types. Finally, the effect of vegetation community restoration was characterized. Experiments show that the vegetation coverage rate is 89.4%; the replanting rate is high, which reduces the difference between the restored vegetation and the surrounding background. After a certain period of vegetation community restoration, it can naturally and continuously merge into the background vegetation, destroying the characteristics of target detection and recognition, and realizing dynamic real-time fusion, and improving the natural similarity of the vegetation ecological restoration system.
Post-Disaster Survey and Analysis of Glass Curtain Wall under Influence of Super Typhoon “Meranti”
Authors: Lin Bin
Published: March 2020

Typhoon “Meranti” made landfall in the city of Xiamen in Fujian province with the maximum wind speed 60 m/s in the center of the typhoon. It caused large economic losses in Xiamen with the severe damages in the glass curtain walls of high-rise buildings. Survey of damaged glass curtain walls was conducted right after the typhoon, including damage amount, damage type and damage level of glass curtain walls. Experimental structural experiments and numerical simulations of wind environment were performed to investigate the failure patterns of glass curtain walls. The causes of damage are analyzed with respect to design criterion, construction, and material. Finally, improvements on the criterion of glass curtain wall design, optimization of wind environment and construction method are proposed to reduce typhoon damage effectively in future.
Application of GM(1,1) Model with X(1)(n) as Initial Value in Deformation Prediction
Authors: Qiu Lijun , Zhang Bo , Zhou Zhanxue
Published: March 2020

The settlement data of a foundation pit monitoring point and the deformation data of a slope monitoring point are taken as the basis. With C# programming language as the development programming language, the GM (1,1) model with X(0)(1)as the initial value and the GM (1,1) model with X(1)(n) as the initial value are established respectively. The fitting results of the model data and the prediction results of the later data are compared and analyzed with the real value. It is found that the accuracy of data fitting and prediction results of GM (1,1) model with X(1)(n) as the initial value is better than that of GM (1,1) model with X(0)(1) as the initial value. In addition, it can meet the precision requirement of deformation prediction in short-term prediction.
Effects of Soil Type on Single Pile-Soil Gap and Force Acting on Pile Body under Low Cyclic Loading
Authors: Xiao Xiao , Heng Yi
Published: March 2020

OpenSees software was be used in this paper as an analysis platform to establish a single pile-soil nonlinear numerical model. The nonlinear mechanical properties of pile nonlinearity and pile-soil gap were being mainly considered in the model. The accuracy of the numerical model was verified by combining the full-scale quasi-static test results of a single pile, which from the literature results, showed that the established numerical analysis model could accurately simulate experimental hysteresis curves of the single pile and the sliding behaviour of the pile-soil interface, and verified the reliability of the model. Further comparison analysis for acting under different soils such as soft clay, medium clay and stiff clay. It was found that under the horizontal low-cycle loading, when the soil around the pile was changed from stiff clay to soft clay, the degree of separation of piles and soils, and the length of the free section increased. For the soft clay, the length of the free section was the longest, which reached 21.3% of the length of the pile. There were significant differences in the distribution of bending moment, shearing force and displacement for piles in three soils. The maximum bending moment, maximum shearing force values of the pile body in the stiff clay were the largest, and the position was closest to the surface and the lateral displacement and equivalent plastic hinge length were the smallest.
An investigation of seismic liquefaction damage and an anti-liquefaction technique for a gravity caisson wharf
Authors: Zhang Xiwen , Zhang Shuaifang , Wang Zhen , Zhang Linlin
Published: March 2020

Gravity caissons are widely used in the construction of coastal ports owing to their simplicity, high capacity, and easy construction. The verification of resistance to seismic liquefaction and earthquakes is necessary and important in the design and construction of coastal ports. In this study, a numerical program was developed based on elasto-plastic theory and a coupled finite element–finite difference method. The seismic resistance of a caisson wharf was assessed using the proposed program. Furthermore, gravel piles were designed to resist liquefaction-induced disaster. It was found that the lateral spreading of liquefied soil would cause large sliding and rotational deformation in the gravity caisson. Adding gravel piles, it can decrease the deformation of the caisson foundation, and improve the stability of the caisson wharf.
Research on Construction Method of Concrete Filled Steel Column
Authors: Yin Yong , Zeng Hong , Zheng Xiaolei
Published: March 2020

As a new type composite structure, concrete fill steel column has a good performance and is widely used in super high rise building. However, concrete pouring and quality control are challenges all the time. Combining with actual engineering projects, this article analyzes key and difficult points existing in concrete filled steel column construction and explores construction in different aspects like selection of construction method, simulated column construction and main construction method introduction. Hoping this article has some help for the similar projects later.
Fire Protection Design of Large-Scale Cold Storehouse in Modern Logistics Based on Risk Analysis and Countermeasure
Authors: Cao Yuanping
Published: March 2020

Cold storehouses in China have been developing rapidly which are centralizing, scaling up and functional subdividing. Cold Storehouse is especially energy-consuming building. Fire hazard of large-scale cold storehouses characterizes large fire compartment, refrigerating medium risk and detecting difficult. According to the relevant regulations at home and abroad, setting fire detecting system in cold storehouses, fire suppression apparatus, effectively organizing put out a fire and the contributory factors of reducing safe risk, all is analyzed in this paper. Then discuss fire prevention from the perspective of fire protection design and put forward the specific requirements for setting fire fighting and rescue site, fire apparatus, eject smoke and danger sources placement.
Research on the Fire of High-rise Residential Building Based on Pyrosim Numerical Simulation
Authors: Hu Guangxia
Published: March 2020

The pyrosim software is used to simulate the smoke characteristics of unit high-rise residential buildings, and the change rules of fire smoke characteristics such as smoke spread rate, visibility, harmful gas concentration, and fire temperature were obtained. The results show that when the fire occurs for 60 s, the environment of the fire site is suitable for evacuation, and the door state of the fire room has a great influence on evacuation. The results of numerical simulation can provide a theoretical reference for fire protection design and evacuation plan of unit high-rise residential buildings.
Experimental Study on The Flexural Capacity of Cold-Formed Thin-Walled Composite Wall
Authors: Wang Quan , Li Guohua , Di Yanqiang , Zhang Yuxia , Zhang Zhijie , Li Mengying
Published: March 2020

To C galvanized thin-wall steel (or thin-walled steel tube) as the skeleton, fiber cement and lightweight concrete composite wall, for three pieces of full scale the wall specimen (Light steel keel + fiber cement board, light steel keel + fiber cement board + lightweight concrete, light steel keel + reinforced expansion net + lightweight concrete) the flexural bearing capacity study, got all kinds of wall shear bearing capacity and displacement performance metrics. The test results show that the cold-formed thin-walled light-steel composite wall has good integrity and strong bending capacity, and the addition of light-steel keel significantly improves the ductility of the composite wall.
Inverse Prediction on the Deformation of a Typical High Loess-filled Foundation during and after Construction— Taking a Key Profile as an Example
Authors: Zhang Jiwen , Cao Jie , Zhu Caihui , Kang Xiaosen
Published: March 2020

To better predict the deformation of the high loess-filled foundation, the values of the parameters of each layer in the high loess-filled foundation are obtained using changing modulus-iterative method. Based on the parameters, the deformation of the high loess-filled foundation during construction was calculated using ideal elastoplastic constitutive model and visco-elastoplastic constitutive model. Comparison between predicted and measured results indicates that the values of the parameters are suitable for predicting the deformation of the high loess-filled foundation.
The Effect of Overburden Depth on the Damage of Underground Structure during Earthquake
Authors: Rajyaswori Shrestha , Li Xinping , Luo Yi , Kumar Mandal Abhay , Xu Kun
Published: March 2020

Nowadays underground structures are essential components in urban areas and their number are increasing continuously. Generally, underground structures show a better performance during seismic actions than structures above ground. During recent strong earthquakes, some urban underground structures suffered severe damages and collapses. Many researchers have worked in this field. Most of them have a common view of shallow underground structures are more vulnerable. Damages in deep underground structures are negligible compared to the surface structures and shallow underground structure. But there are some case histories, where there is severe damage in deep underground structure too. So we cannot neglect the seismic damage of deep underground structure. Nowadays there are many deep underground structures being constructed and in operation. We need to take into account the safety of the deep underground structure. The influencing factors for causing damages in deep underground structures should be studied carefully. In this paper, various case studies are taken into consideration and their results are observed. And the damages in different underground structures at different locations due to corresponding earthquakes are studied and compared, and the pattern of damage occurrence is reviewed.
Surface Subsidence Monitoring in Mining Area Based on SBAS Method Fusing Distributed Scatterers
Authors: Deng Jun
Published: March 2020

Coal mining in Peixian County, Jiangsu Province has a long history, and the surface subsidence of mining area is obvious. To better grasp the characteristics of long time-series surface subsidence in of mining area, this paper uses SBAS method fusing distributed scattererst to process 14 Sentinel-1A images ranging from October 2016 to April 2017, and obtains the deformation field caused by mining in Zhangshuanglou(ZSL) mine. The results show that SBAS method based on distributed object fusion can effectively monitor the surface subsidence. The maximum subsidence of Zhangshuanglou mining area reached - 209.3 mm in the period from October 2016 to April 2017, and there is a trend of gradual increase of surface subsidence. It needs to be early-warning through time series observation.
Strength Reduction Factor of FS Model Subjected to Near-Fault Pulse-Type Ground Motions
Authors: Dong Huihui , Han Qiang , Du Xiuli
Published: March 2020

This paper focuses on the strength reduction factor spectra for self-centering (FS) model subjected to near-fault ground motions with pulse-type based on nonlinear dynamic analysis of single degree of freedom (SDOF) system. In order to investigate the influence of the the FS model on the strength reduction factor, the ratio of the strength reduction factor of the FS model and that of Elastic-Perfectly-Plastic (EPP) model is evaluated and discussed. The ratio is larger than 1.0 and the maximum value can reach 1.35 during medium and long period. This result indicates that it is conservative for the structural design of the self-centering structure when the strength reduction factor for EPP model is used. The investigations of the effects of the post-yielding stiffness ratio and the energy dissipation ratio of the self-centering model on the strength reduction factor are also carried out.
Analysis of Strata Disturbance of Buildings Reinforced by Grouting under Small Radius Curved Shield
Authors: Zhang Xingang , Zhang Qianli , Li Taifeng , Liu Jingyu
Published: March 2020

The influence of shield tunneling process on surrounding buildings, pipelines and roads is in the final analysis caused by segment disturbance of surrounding soil, so it is of great significance to study the disturbance of shield tunneling process on surrounding soil. Based on the monitoring of the vertical displacement of the soil mass and the horizontal displacement of the inner and outer sides of the segment during the excavation, the disturbance of the surrounding soil mass caused by the small curvature radius turning of the shield machine passing through the pre reinforced building is analyzed. The results show that the maximum settlement of soil disturbance during shield tunneling is 4 mm, the maximum camber is 20 mm, the lateral displacement is 3.9 mm, and the internal displacement is 3.7 mm. Under the double influence of foundation pre grouting reinforcement and small curvature radius turning, the soil has a certain camber. This study provides a reference for the construction of shield machine passing through the pre reinforced section with small curvature radius.
Application of Unloading Fractured Rock Mass under Uniaxial Tension Based on Endochronic Theory
Authors: Yu Li , Tu Bin
Published: March 2020

In this paper, the constitutive relation of fractured rock mass under uniaxial tension is derived, and the corresponding numerical solution is obtained. It is found that the kernel function with the Proney expansion can fit well with the ρ(z)=Cz
−α
. When the parameters of the kernel function are taken from the experimental data, the constitutive equation can be simplified in the initial loading stage, which is in good agreement with Jin Fen α = 0.5 gnian’s experimental data under unloading condition. The simplified equation of the endochronic theory is well verified by the experimental data.
Research of Slope Disaster Chain-Stage and Evolvement Rules
Authors: Wang Yu , Shu Zongying , Li Yongyu
Published: March 2020

The slope disaster chain-stage characteristics are intuitive, visual and vivid, and it is the key of understanding the chain evolvement rules. This paper summary of the slope disasters chain-styled characteristic, and divide the chain-styled developmental stages. The principle and evaluative law of slope disasters are expressed by chain-styled relation, so that chain-cutting disaster reduction can be pertinently controlled based on adequately grasp of the characteristic of each chain-styled stage. When the slope disasters are in the weak environment, we carry out chain-cutting disaster mitigation, which will be able to resist the disaster evil to threaten the human, and have possibility and great significance of disaster prevention.
Analysis on Bearing Capacity Factor Nc of a High Loess-Filled Foundation Using a Unified Elastoplastic Finite Difference Method
Authors: Zhang Jiwen , Kang Xiaosen , He Yuqi , Liao Hongjian
Published: March 2020

To obtain the bearing capacity factor of a high loess-filled foundation in Shaanxi Province, China, a serious of numerical calculations on a nonhomogeneous model were conducted using a unified elastoplastic finite difference method. It was found that the bearing capability factor Nc
increases as the friction angle ratio ξφ
and cohesive force ratio ξc
. Furthermore, the bearing capacity of loess-filled foundation can be improved by increasing the degree of density and adding cementation in construction. As an example, during the construction of the high loess-filled foundation, the bearing capacity was improved by making the degree of density come to 0.93. In addition, the width and depth of the slide surface increase as the friction angle ratio ξφ
and ξc
Research progress of soft soil foundation treatment technology
Authors: Jiang Xiaoyi , Lu Qingrui , Chen Shijun , Dai Renhui , Gao Jinhe , Li Ping
Published: March 2020

With the extensive improvement of infrastructure in China in the past ten years, the soft soil foundation is becoming more and more complicated. Therefore, the improvement of soft soil foundation treatment has become a difficult problem that today’s engineering designers have to face. This paper systematically reviews the development of soft soil foundation treatment technology in our country, and emphatically introduces the development process of foundation treatment at home and abroad, especially in our country in recent years, which embodies the cross and comprehensive application of various foundation treatment technologies and forms a unique composite reinforcement technology.
Influence of stratum simplification on stability reliability index of loess slope
Authors: Liang Yan , Chen Chen , Huo Aidi
Published: March 2020

In the calculation of loess slope stability, most of the studies are based on the simplified calculation of the actual slope stratum, and it will affect the calculation results, so the influence of the simplified method of stratum on the slope stability analysis is discussed. Taking the stability analysis of the South Plateau of Jingyang as an example, the stability safety factor, the probability of failure and reliability index of the measured strata model (MSM) and three simplified models are calculated and analyzed based on the Morgenstern-Price method and Monte Carlo reliability analysis method. After comparing the calculation results, it is concluded that the simplification of the model will not have a great impact on the stability safety factor of the slope (in this example, the variation range is less than 0.026), but it has a significant impact on the failure probability and reliability index (in this example, the maximum difference of the failure probability between the simplified models and the MSM is 54.8%). The simplification method is an important factor affecting the calculation results, and unreasonable simplification will cause changes in the critical slip surface and large differences in reliability index.
Study on Influence of Slope Blasting Excavation on Stability of Adjacent Dangerous Rock Mass
Authors: Peng Xiaoyong , Wang Zhangyun , Ma Kang
Published: March 2020

Through mechanical analysis, combined with the instability mode and failure mechanism of dangerous rock mass, taking into the consideration of the influence of blasting excavation of the dangerous rock mass on the dynamic characteristics of it based on the limiting equilibrium method, the stability equations of dangerous rock mass at adjacent side slope with blasting and excavation under explosion load are derived. The engineering practice shows that the slope blasting has obvious influence on the stability of the adjacent dangerous rock mass, and the distance R between the blasting point and the dangerous rock mass and the explosive quantity Q are the key factors affecting the stability coefficient of the dangerous rock. The stability of the dangerous rock mass increases with the increase of the distance R, and decreases with the increase of the explosive amount Q. It is suggested that the impact of the blasting vibration force on the adjacent dangerous rock mass should be considered when the slope blasting is excavated.
Impact Analysis of the Base Stress Caused by Subgrade Settlement behind Culvert under G-300 Load
Authors: Yang Jiayong
Published: March 2020

In order to analysis of influence of base stress on foundation caused by the subgrade sinking behind the culvert pier under G-300 load. Based on the analysis of the calculation parameters and methods of reinforced concrete slab culverts under the G-300 load, a culvert with a clear span of 4 m, a clear height of 3 m and a filling height from the culvert top of 0.5-8 m was taken as an example for the calculation of base stresses with and without downward frictional resistance. The compared results showed that the base stress increases by 68.2-142.3 KPa when there is downward frictional resistance. Under the action of P6’, σ Max and σ Max’ increased obviously with a large increment, which should be paid attention to in the actual design process. Because the force of the action of P6’, the base stress has exceeded the bearing capacity of the foundation, which caused the foundation induced, or increased the uneven settlement of the culvert foundation. And it finally resulted in the damage and the use of the culvert.
Improved Mechanical Properties of Asphalt Mixture Using Vacuum Compaction Method
Authors: Chen Shibin , Shi Xingtai , Yao Yunshi , Gao Yongchang , Su Pei
Published: March 2020

A novel vacuum compaction method, aiming to improve mechanical properties of asphalt pavement, was developed and compared to common compaction method. A compaction cylinder with a hole of adjusting air pressure was designed and fabricated and was utilized for finishing vacuum compaction and common compaction. Compared common compaction, at vacuum degree of-0.04 MPa air void of the sample after compaction decreases by 6.25% and at vacuum degree of-0.08 MPa it decreases by 10.9%, which indicated that vacuum compaction is more efficient than common compaction. Similarly, the changing of voids in mineral aggregate also exhibited the same trend, which indicated that vacuum degree at -0.08 MPa is the most efficient value. Through splitting test, splitting strength under vacuum compaction was higher than that under common compaction, by 10.2%. Furthermore, the ability of strain-stress increased by 11.55% by applying vacuum compaction. These results prove that the mechanical properties of asphalt pavement were optimized by the use of vacuum compaction instead of common compaction.
Low Temperature Crack Resistance and Fatigue Properties of Asphalt Mixture with Pre-buried Heat Conduction Tube
Authors: Zhuang Chuanyi , Zhao Xiaotong , Ye Yali
Published: March 2020

In order to study the effect of geothermal heat transfer tube on the asphalt pavement performance, a heat transfer tube with a diameter of 8 mm was used, which was placed in an AC-16 hot mix asphalt mixture and crushed into a ruthenium plate test piece, using MTS-810 hydraulic servo test. The system evaluates the low temperature crack resistance and fatigue performance, and compares the performance with the asphalt mixture test piece without the heat conduction tube. The results show that after the heat transfer tube is buried, the failure strain of the asphalt mixture is reduced by 40.9%, and the repeated load of the three-point bending fatigue test is reduced by 53.9%. The low temperature crack resistance and fatigue performance are both larger. The degree is reduced.
Study on Fatigue Performance of Pre-Stressed Concrete Box Girder
Authors: Zhou Hongyu , Ma Quanzhou , Yuan Hui , Zhou Yun
Published: March 2020

In this paper, the design parameters and fatigue loading parameters of pre-stressed concrete box girder are introduced, and the multi-stage variable amplitude fatigue test is carried out. The finite element model of pre-stressed concrete box girder is established by using ANSYS finite element software. Comparing the test results and simulation results, it is found that the load-deflection curve of N=2 million times are in good agreement. The principle of the whole fatigue process analysis method is introduced. On this basis, the cumulative damage under different fatigue times is obtained. The fatigue reliability analysis and sensitivity analysis of random variables are carried out by using the PDS module in ANSYS.
Research on Fatigue Reliability of Prestressed Concrete Beams Considering Size Effect
Authors: Zhou Hongyu , Liu Yanan , Cao Xiaoqing , Liu Hongyu
Published: March 2020

In order to study the fatigue reliability of pre-stressed concrete simple-supported beams that considered the effect of size effect, using the existing method to check the fatigue reliability of the test-piece. The fatigue test of three pre-stressed concrete simple beams was carried on, which the size of the beams was different, and collected the data of the fatigue test. Used hierarchical checking method, a second-order moment method to check the reliability of the beams, compared the results of fatigue reliability which calculated by two different checking methods. Analyzed and summarized the effect of size effect on fatigue reliability.
A Study of Size Effect in Shear Resistance of Reinforced Concrete Beams Based on Machine Learning
Authors: Fan Xuefeng , Wang Shijun , Zhang Zhen
Published: March 2020

Size effect is common in structural engineering where a large component fails at lower stress level than a tiny one made of the same material. As a result, the calculation of the loading capacity of a structural component need to be revised when size effect is considered, especially for the reinforced concrete (RC) beam under shear loading. However, due to inadequate theoretical analysis of the size effect in shear failure, the calculation of shear strength in codes all over the world is far from accurate. In this research, the machine learning method, which can efficiently analyse and process data, is applied to study the size effect in shear strength of beams via exploring the experimental data collected worldwide on shear failure of RC beams. The back propagation (BP) neural network model of shear strength of RC beams is built and trained by the data exist, and then give a prediction of shear strength. The values predicted are compared with the values calculated from codes and Bažant size effect formulas and the experimental data, which indicates the feasibility and superiority of machine learning method in dealing with size effect in shear failure.