bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Blasting Vibration Characteristics of Shallow Tunnel under Unsymmetrical Pressure
Authors: Gao Wen Xue , Sun Xi Meng , Hou Bing Hui , Chen Ning Ning
Published: October 2012

Based on Huolangyu tunnel of Mixing road, this paper researches the monitoring of ground surface vibration and the technology of controlled blasting. Monitoring and analysis results show: The ground surface vibration decline from constructed position to un-constructed position along tunnel excavation direction. The maximum ground surface vibration locates at the shallow position along tunnel cross section. The surface vibration velocity main vibration frequency has more than one advantage frequency, main vibration frequency concentration distribution in 20～40Hz low frequency band. Tunnel driving, the emphasis of the blasting vibration should focus on control of tunnel excavation area has the upper, lining structure and shallow buried in the influence of the surrounding rock; Tunnel through the surface buildings, cannot ignore already forming of blasting seismic effects of tunnel amplification and resonance effect.
Numerical Analysis of New Shield Tunnel on Mechanical Behavior of Existing Parallel Tunnel
Authors: Li Xue Feng , Du Shou Ji , Zhang Ding Feng
Published: October 2012

A three-dimensional numerical analysis was conducted to investigate the effects of a new shield tunnel excavation on the internal forces and deformation induced in an existing parallel tunnel and soil plastic zones around it. Special attention was paid to the influence of relative positions between two tunnels. The results of the analysis show that the relative positions affect the mechanical behavior of the existing parallel tunnel and the soil mass behavior around it. When a new tunnel is driven below or above an existing parallel tunnel, important increments are induced in deformation and bending moment in the lining of existing tunnel at its crown and springline, compared to that of induced by new tunnel excavation in horizontally parallel to the existing one. The plastic zones around tunnels also extend larger when tunnels are driven in vertically parallel than they are in horizontally parallel. For the safety concern, it is concluded that horizontally parallel configuration model between two tunnels should be adopted in practice.
Management Criterion for Large Deformation Tunnels
Authors: Zhang Su Min , Zhu Yong Quan
Published: October 2012

The limit displacement was calculated with regard to a large deflection tunnel. The continuum calculation model was established with actual parameters of the surrounding rock of the tunnel as input. In the simulation calculation, the action occasion of the support structure was determined based on the ratio of the measured rock pressure to the geo-stress, and the bearing capacity of the R.C. compressive bending component of the support was expressed with the axial force and bending moment on losing capacity of the support structure in loading; The limit displacement of the tunnel wais determined finally combined with the measured displacement of control points on collapsed or gauge-intrusive sections and cracked primary support or secondary lining sections. Since the deforming rate is more concerned than the displacement in drill and blast tunnel construction, three-level-management of deflection and deforming rate was proposed based on the statistical analysis of measured deforming rate, and the safety requirement for deflection control in construction. The management criterion has reference value to other similar tunnels where difficulty is encountered due to large deflection occurring in construction.
Application Study of the Calculation Method for Loads of Multi-Arch and Extra Large Cross Section Tunnels in Double-Side Drifts Construction Method
Authors: Xu Chong Bang , Zhao Xu
Published: October 2012

The calculation method for load of multi-arch and extra large cross section tunnels (MELCST) is a new method accounting for the influences caused by the multi-step construction procedure and temporary support on tunnels. The paper analyses the application of the method in the double-side drift construction method, and gives the distribution mode and the value of loose loads in various construction sequence, example analysis is also given through Luohanshan tunnel.
Analysis on Safety Range of Supporting Force at Excavation Face of Shield Tunneling in Xi’an Metro
Authors: Yan Zhi Guo , Liu Dian Shu , Jiang Yu Sheng
Published: October 2012

Based on the tunnel engineering of Xi’an metro, according to the specific geological conditions, used FLAC3D numerical simulation software, the paper determine the minimum supporting force of the excavation face by two monitoring points’ settlement as the standard. The point at the surface above the excavation face and the other at the top of excavation face. When buried depth of tunnel is greater than 1.5 times the diameter of hole, the surface point cannot effectively reflect the deformation of soil around the tunnel, it should monitor and control the deformation of soil by the top point. The paper determine the maximum supporting force of the excavation face by the analysis of the settlement at the top points in different buried depth of tunnel. Obtain the safety range of supporting force in shield machine excavation face. According to the surface uplift larger phenomenon in shallow tunnel, put forward corresponding countermeasure. It is of great significance to apply reasonable supporting force at excavation face and prevent the surface subsidence and uplift crossing the locations that tunnel depth have large changes.
Influence of Water Saturation on Dynamic Responses of a Partially Sealed Tunnel
Authors: Wen Min Jie , Su Zi Ping
Published: October 2012

The mixture of water and gas is treated as a homogeneous fluid. Based on Boit’s theory, the influences of water saturation on the dynamic responses of a partially sealed tunnel are investigated in the frequency domain. By utilizing the continuous condition, the analytical solutions of the displacement, stress and pore water pressure of a partially sealed tunnel in the nearly saturated soil are derived subject to the harmonic load. On this basis, the influences of water saturation and permeability coefficient on the system responses are discussed by the numerical example. It is shown that the water saturation has a great influence on the stress and pore water pressure amplitudes. In addition, the permeability in the boundary of the tunnel is reasonably described by the permeability coefficient.
Research and Discuss on Development of Deep Tunnel Bolt Supporting Technology
Authors: Liu Jun Chao , Liu Xi Liang , Ren Lian Wei
Published: October 2012

resistance increasing bolt with large deformation has the advantage of both let-pressure bolt and resistance increasing bolt，it makes best use of the advantages and bypass the disadvantages of the two types of bolt，so it can achieve the goal of improving the bearing capacity of surrounding rock and stably bolting the surrounding rock. With more and more retractable anchor are being researched and developed, it is more necessary to research and develop the retractable anchor which can both have the function of let pressure and increasing resistance. Though the way of analysising and summaring the experimental study and application of retractable anchor at home and abroad systematically，the understanding of the retractable bolt is being inhanced，the intact theoretical and practical basis is provided for the extension of this kind of anchor. Finally，the development of retractable anchor in the future is prospected. Resistance increasing bolt with large deformation which both have the function of let pressure and increasing resistance is a kind of retractable anchor，which can apply to deep weak and broken surrounding rock. Therefore，it is worthy of researching and applying.
Vibration Characteristics of Air-Entrained Concrete Based on Slipform Construction
Authors: Zhang Yan Cong , Gao Ling Ling , Shen Jun Min
Published: October 2012

Vibration characteristics of air-entrained concrete was analyzed by vibration slump loss, formwork ability and vibration viscosity coefficient through comparative testing. The results showed that: air-entrained concrete has a characteristic that high slump in vibrating and low after. It was significance to construction with slipform paver. Air-entraining agent improved the concrete structural viscosity under high-frequency vibration was the reason for this characteristics.
Theoretical Study on Thaw Settlement of Saturated Frozen Soil
Authors: Ming Feng , Li Dong Qing , Zhang Kun
Published: October 2012

The consolidation of frozen soil is a coupled action of temperature and deformation. Using moving boundary method and taking the void ratio as a variable, the large strain thaw consolidation mathematical model is built according to Gibson’s large strain consolidation theory and thermal conductivity equation with consideration of phase change. In order to verify the model, a simple example is simulated by FEM software. The result shows that the consolidation range and consolidation rate are decided by the temperature boundary; the change of void and deformation are influenced by pore pressure dissipation and the thaw process in permafrost are delayed by consolidation process.
Study on the Design Method of Energy-Saving Slope in Subway
Authors: Xu Hui Zhi , Cheng Guo Zhu , Wu Chong
Published: October 2012

The energy-saving slope is an important part in longitudinal design in subway. The paper’s aim is to find the optimal length of energy-saving Slope. So, the paper set a model and calculated method based on dynastic and braking of vehicle. It divides the tunnel into five intervals: accelerated, downhill energy-saving, Traction – idle, uphill energy-saving, braking. To calculate the length of energy-saving slope based on the change theory between Kinetic energy and Potential energy. The result shows that longer of station distance, smaller of max-speed and motor power, greater of angle of slope and carriage quality, needs longer to energy-saving slope. Recommend length of energy-saving slope was [228m, 330m].
Feedback Analysis Method and Its Application on Consolidation Settlement of Subgrade
Authors: Fu Cheng Hua , Zhou Hong Bo
Published: October 2012

Subgrade consolidation settlement was the basic content of deformation monitoring and settlement assessment for the railway, controlling settlement deformation was one of the key factors for the project. Based on measured settlement from subgrade, major mechanical parameters about subgrade soil were obtained by finite element method and BP neural network. After obtaining these parameters, finite element calculation would be done for consolidation settlement about subgrade, the deformation from pavement in different periods and post construction settlement and the average degree of consolidation for every stratum would be predicted based on the results, feedback analysis on consolidation settlement for the subgrade would be obtained. The results from it’s application in a railway subgrade project show that: this method may not only obtain rapidly the major mechanical parameters of soil layer, but also predict the consolidation settlement from subgrade reasonably. It can provide a good reference for the design and the operation and the settlement assessment in the railway project.
Determination of the Rural Highway Subgrade Work Zone Depth
Authors: Chang Yu Jiao , Ma Biao , Wang Yu
Published: October 2012

Using the finite element method, influences of vehicle load, subgrade fillings and compactness on the subgrade work zone were analyzed, of which the traffic load impacts most. Considering the traffic and mechanical character of the subgrade, it is determined that the appropriate subgrade work zone depth of rural highway is 1.0m. As a result, applying proper work zone depth plays an important role in the construction cost of rural highway.
Effect of Crushed Rock Layer Width on Natural Convection Cooling of Highway Embankment in Permafrost Regions
Authors: Yang Li Jun , Sun Bin Xiang , Wang Wei , Liu Qi
Published: October 2012

For the construction of the proposed Qinghai-Tibet Express Highway in permafrost regions, it will be necessary to use the new technique of cooling the ground temperature by the coarsely crushed rock layer with a low fines content. The heat convection governing equations based on airflow function in variable permeability porous crushed rock layer are derived. Comparison of the cooling capability of winter-time natural convection in the crushed rock highway embankments with various widths of crushed rock layer and an air-permeable side slope surface were studied using a finite element method. The result indicates that the cooling capability of natural convection within the crushed rock highway embankment with a crushed rock layer width of 12 m is stronger than that with a crushed rock layer width of 10 m. Under the same temperature and pressure boundaries, the storage of cold energy in the foundation soils below the wider crushed rock highway embankment due to natural convective heat transfer is larger than that below the narrower one.
Improving the Computational Efficiency of Widening Highway Approach
Authors: Sun Xiao Yu , Wang Zhen Qing , Xing Hong Tao , Tong Yong Heng
Published: October 2012

In this paper we propose a stepwise genetic algorithms approach for optimizing highway alignments for improving computational efficiency and quality of solutions. Our previous work in highway alignment optimization has demonstrated that computational burden is a significant issue when working with a geographic information system (GIS) database requiring numerous spatial analyses. For solving real-world problems working directly with real maps through a GIS is highly desirable. Furthermore, saving computation time can enhance adoptability of a model especially when a study area is relatively large, or involves many sensitive properties, or if locating complex structures such as intersections, bridges and tunnels is necessary. It is well acknowledged that in many optimization processes subdividing large problems into smaller pieces can decrease the computation time and produce a better solution. In this research two different population sizes are used to develop a stepwise alignment optimization when employing genetic algorithms in suitably subdivided study areas. An example study shows that the proposed stepwise optimization gives more efficient results than the existing methods and also improves quality of solutions.
Different Chosen-Unit-Weight Shear Resistant Property of the Asphalt Mixture on the Bailey Method
Authors: Zhang Yu , Han Bing , Sun Bo Wei
Published: October 2012

This paper studied on the different chosen-unit-weight shear resistant property on different temperature with direct shear test. The results show that the shear strength on 60°C and the dyna mic stability in rutting test on 60°C have familiar trend, the shear strength and the dynamic stability in rutting test have a good relationship on evaluating the high temperature stability of the asphalt mixture. Based on the performance demand ,this paper gives reasonable Bailey parameters Chosen-unit-weight range.
Evaluation on Bearing Capacity Improvement of Cast-In Situ Bored Piles Using Post-Grouting Technology
Authors: Cai Jing , Wang Yong Yu , Wang Xin Hua , Yan Hua Wei
Published: October 2012

Post-grouting technology is an effective method of improving mud cake in the pile tip and debris in the pile side. What’s more, it is also considered as a great method to improve the bearing capacity of the cast-in-situ bored pile. The post-grouting technology is used in the foundation of a tall office building in Shan Dong province. For this project, comparing results of the static load test and the theoretical calculation, some conclusions can be made that the bearing capacity of post-grouting pile is 126.5% more than that of unpost-grouting one, the ratio between the tip resistance and the side resistance of the post-grouting pile are 39.8% and 60.2% respectively, and the ratio between the tip resistance and the side resistance of the unpost-grouting pile are 28.9% and 71.1% respectively. It is estimated that the cost of cast-in-situ bored piles using post-grouting technology is 45%~50% cheaper than the unpost-grouting piles.
Study on the New Concept of the Highway Maintenance
Authors: Jiang Qing , Ma Rong Guo , Ye Zhen
Published: October 2012

The goal of the highway maintenance achievement and effect contract management is to maximize reduce the maintenance cost, prolong the service life of the highway; preventive maintenance investment little, benefit is good, spend less money, and prevent illness.
The Measurement of Thickness and Model Prediction of Hot Asphalt Mixture in the Rolling Compacting Process
Authors: Chen Xiao , Zheng Jian Long
Published: October 2012

The thickness test and models prediction methods and rheological deformation theory have an important impact on quality control in the process of hot asphalt mixture field rolling compaction. DSL30 leveling instrument are used to measure the thickness in the process of hot asphalt mixture. Pt100 and Paperless Recorder are joined to test the temperature field and results of compaction thickness and temperature changes are obtained, and the model is established for mixture rheological deformation theory and compaction thickness prediction. The results shows that: by using the thickness and temperature field test methods, relevant data of hot asphalt mixture can be gained accurately, viscoplastic rheological theory correctly reflects its deformation behavior and the thickness forecast model can efficiently show the mixture layer. In this way, new methods are provided for the asphalt pavement quality control, rheological theory and temperature fields testing.
Cohesive Cracking Simulation of Asphalt Mixture with Reflective Crack through XFEM
Authors: Zhang Jia Min , Zhang Bo , Wang Jin Chang
Published: October 2012

Firstly, the parameters of cohesive zone model in ABAQUS software are calibrated through the cohesive constitutive model determined by cohesive potential energy, which is provided by Oriz and Pandofi（1999）. Then, the validity and liability are verified by the single element example which compares extended finite element simulation with experimental results. Lastly, it puts forward the model of FEM based on the highway pre-sawed cracks. The curve of CMOD with changing temperature is obtained, and the curve can be divided into three stage segments. The middle stage segment changes dramatically for the local cracking in the crack tip field between asphalt surface and base. The research results illustrate the cracking mechanisms of asphalt pavement under changing temperature.
Uniaxial Compression with Acoustic Emission Experimental Study on Rock Damage Process
Authors: Liu Jing Hong , Liu Xiao Hua , Han Wen
Published: October 2012

Acoustic emission technique is an important technique for monitoring crack propagation and failure process of rock, coal and concrete material. A uniaxial compression test with acoustic emission monitoring on coal and rock samples’ deformation and failure process were carried out. Failure precursor information of rock, coal and concrete material were studied through contrast analysis the experiment result include acoustic emission signals, strain, load correlation of sample inner crack propagation to failure process. The test provided necessary data to further understand on rock burst failure disaster. The test result provides a theoretical basis for further application of acoustic emission for prediction coal rock dynamic disaster, assessment rock and concrete structure stability and study rock concrete material failure process mechanism.
Analysis of Research Topic on Cement Cold-Recycled Base of High-Grade Highways
Authors: Liu Tao , Ming Tu Zhang , Hu Guang Wei
Published: October 2012

This review presents the difference between cement cold-recycled base and cement-stabilized new aggregate base. Old aggregate gradation is obviously beyond the prescribed limits. Due to old cement hydration products, the gradation of old mixture is not real by screening test, just called it “Fake Gradation”. The various factors of influence on pavement performances are introduced, including cement content, gradation, fine aggregates content, old material characteristic and water loss ratio. The main pavement perforamnce, such as mechanical properties, shrinkage properties and fatigue properties of cement cold-recycled mixture may not meet the requirement of high grade highways. The research topic of cement cold-recycled base is pointed out, which includes properties of old materials, the application of additives, the methods of improving pavement perforamnce and the establishment of pavement performances evaluation indexes, etc.
Roadway Hard Rock Loose Blasting by Digging Machine Technique
Authors: Fu Ju Gen , Luan Rui Xuan , Zhang Yan Ting
Published: October 2012

Rock roadway digging machine is generally applicable to soft mudstone, sandy mudstone roadway. When it comes to the harder rock,, the speed of digging machine construction is greatly reduced, the tool were wear seriously, the service life is substantially reduced, the tunneling cost is dramatic increased. So we must use the loose secondary blasting, to soften rocks. According to the specific circumstances of the west lane in Liuzhuang Coalmine, and proposed coal mine loose blasting technique program in keeping with construction requirements after the study, that is reasonable blast-hole depth, hole parameters, charge amount, charge structure, stemming length. Research results have a good loose blasting effect in engineering practice.
Mountain Road Typical Slope Stability Assessment and Control Measures
Authors: Wang Sheng Li , Wang Qiu Shen , Li Lei , Ren Jing Ke
Published: October 2012

This article through to the typical geological disaster investigation of the 307 national road sections, analyzes the main causes of the disaster, the typical section the slope body risk analysis and stability evaluation, and put forward the reasonable management plan and the suggestion.
Tailings Dam Stress and Deformation Research Based on the Theory of Elastic-Plastic Theory
Authors: Li Zong Wei
Published: October 2012

This paper introduces the principle of the elastic-plastic model based on Mohr -Coulomb failure criteria, Combination of a tailings dam introduces the modeling analysis process, according to the actual project analyses the stress and deformation calculation results of rationality.
Comparative Study of Different Form of Asphalt Mixture Viscoelastic Rheological Model
Authors: Li You Yun , Zheng Xin Bo , Yi Zhen
Published: October 2012

In this paper, based on the essential attribute of the asphalt mixture, the characteristics of the asphalt mixture creep deformation were analyzed. With the comparison of the theoretical and experimental results, the advantages and disadvantages of the common rheological models used as the reaction of asphalt mixture creep characteristics were studied. The characteristics of of the asphalt mixture deformation have been analyzed. For the accurate response of nonlinear viscous elasticity model of asphalt mixtures must be a reasonable combination of the characterization of deformation characteristics of various components, this paper reveals the rheological deformation of asphalt mixture of components and parts of correspondence with the proper models. Finally, the experimental data were given to verify the correctness of the proposed model.
Elastoplastic Analysis of Asphalt Concrete Pavement
Authors: Ren Hong Peng , Wang Jin Chang
Published: October 2012

Drucker-Prager linear elastic-perfectly plastic model and the associated flow rule, a numerical simulation study has been conducted on the layered asphalt concrete pavement structure, using the 2D axisymmetric finite element method (FEM). Pursuant to empirical equation of the stability, cohesion and internal friction angle of asphalt concrete, and in line with experimental test subjects on pavement material and pavement performance, the impact of mechanical parameters of each layer of asphalt concrete on the road surface deflection and the evolution law of plasticity in each structural layer under standard axle load has been studied.
Compared Analysis of Embankment Thermal Stabilities in High Temperature Permafrost Regions with and without Climatic Warming
Authors: Li Dong Qing , Huang Xing , Fang Jian Hong
Published: October 2012

The heat stabilities of embankment on the high temperature permafrost regions in the eastern Tibetan Plateau without climate warming and with air temperature rising speed of 0.04°C/a were modeled, and the heights of embankment were discussed and figured out, comparatively and respectively for asphalt-paved, concrete and gravel road surface, according to the natural geographic and geologic conditions in the high temperature permafrost regions in the district. The different confined conditions about embankment critical heights with climate warming and without climate warming were discussed in the paper. Finally, the result had been obtained by numerical calculation: in the high temperature area, for the two types of laying of cement concrete and gravel surface road, the two critical heights of the thermal stable conditions were (road operation for 30 years), respectively, do not consider climate change as 2.5 m and 2.0 m, consideration of climate change were 3.5 m and 3.0 m.
The Theoretical Analysis of Performance Evaluation Connotation of Rural Highway Projects
Authors: Wang Wu Gong , Ma Rong Guo , Feng Kun , Liang Guo Hua
Published: October 2012

On the basis of defining the concept of rural highway project performance, the necessity of the project performance evaluation of rural highway is analyzed. According to the theories of government's public function, fiduciary responsibilities accountability and public finance, the relation between rural highway and public finance are made researches on. Furthermore,with the application of the demand level theory of Maslow, the interrelationship among objects of the rural highway project performance evaluation is made an analysis of, and on top of that, combined with SWOT analysis method, the demand and goal of rural highway project performance evaluation are put forward.
Application of Fractal Theory in Aggregate Gradation Research
Authors: Tan Bo , Yang Rui Hua , Lai Yan Ting
Published: October 2012

The paper presents the fractal dimension formula of distribution of asphalt mixture aggregate diameter by the deducing mass fractal characteristics function. Taking AC-20 and SMA-20 as examples, selected 6 groups of representative grading curves within the grading envelope proposed by the present specification, and calculated their fractal dimensions. The asphalt mixture gradation has fractal dimension D (D∈(1,3)), and the fractal of continuous gradation is single while the fractal of gap-gradation shows multi-fractal with 4.75 as the dividing point. Fractal dimension of aggregate gradation of asphalt mixture reflect the structure characteristics of aggregate distribution, that is, finer is aggregate, bigger is the fractal dimension.
Research on the Level Soil Pressure of Multi-Stage Retaining Wall in Mountain Road
Authors: Li Peng , Wan Hai Tao
Published: October 2012

This study presents the research of soil pressure distribution form of multi-stage mountain gravity retaining wall through specific engineering tests. There has a further discussion on the soil pressure calculation formula of the multi-stage gravity retaining wall in different conditions, which aims at providing the useful reference for the formal construction design.
Surface Structure of Asphalt Pavement Non-Nuclear Density Gauge Density Test Results the Impact Analysis
Authors: Zhao Hai
Published: October 2012

In order to study the influence degree of the different asphalt mixture surface texture structure to the test of Non-nuclear density gauge(Pave Tracker™ Plus 2701-B). This thesis utilized non-nuclear density gauge and surface sanding method for different types of mixtures were compacted density and surface texture depth test. The results showed that: It can produce certain effect, and with it the inhomogeneity of the increases. This is mainly about mixture gradation type, among them SMA-13 affect the minimum, AC-20 take second place, ATB-25 maximum. However, using the surface sand can effective to reduce its impact. So, recommendations for ATB-25 type mixture can be used to detect the surface sand, and the SMA-13 and AC-20 are not used.
Analysis of the Mode of Crushing and Stability in Old Cement Pavement during Asphalt Overlay Project
Authors: Wang Hua , Wu Yun Feng , Ye Song
Published: October 2012

In the process of old cement concrete pavement is transformed, asphalt overlay is the common method. However, due to the cracks of the original cement concrete slab when load and temperature and humidity changes will produce a relative displacement, it can not avoid reflective cracking. So in order to prevent the reflective cracking of asphalt overlay, crush the old cement concrete pavement is the important manner. Different construction technology is divided into three kinds: cracked steady pressure, impact compaction and rubblization technology. Among these, rubblization is an important technology that utilizes in-situ crushing technique in cement concrete pavement. This article discusses the characteristics of these three techniques, and it also evaluates effectiveness.
The Engineering Application of Multifunctional DGT-1 Spraying Wall Composite Steel Template
Authors: Lv Jian Hua
Published: October 2012

With the traffic infrastructure increasing in China, the techniques for concrete structures have to not only meet the design requirements but also improve its requirements of appearance quality in bridge engineering. The appearance quality requirements of As-cast Finish Concrete has become highway project structure standard; And we successfully developed the multi-function DGT-1 spraying wall composite steel template through the designs of different templates and contrast test research of template surface treatment; Engineering has proved that concrete structure used the template pouring not only can reach the requirements of As-cast Finish Concrete in appearance quality, but also have larger of advantages in turnover number, convenience of using, speeding up engineering progress, environmental protecting, and savings costs.
Sensitivity Analysis on Dynamic Properties of Large Span Concrete-Filled Steel Tube Arch Bridge
Authors: Sun Hang , Han Xiao Jian , Gao Xiu Yun
Published: October 2012

The calculation formula of the vertical fundamental frequency of arch bridge has been given in current design codes, in which the rise-span ratio is the only variable on condition that the structure mass and stiffness are known. However, the dynamic properties of long-span concrete filled steel tube arch bridges have their own characteristics, which are influenced by a series of factors. Thus this article establishes a space model of a concrete-filled steel tube arch bridge. By analyzing the main design parameters’ influence on the structure dynamic properties, including rise-span ratios, arch-axis coefficient and wide-span ratios, some of conclusions has been made, which can be used for further research of the impact effect and earthquake dynamic response, and provide the necessary basis for the dynamic design of bridges of this kind
A Comprehensive Method of Determining Cable Force during Closure Condition for CFST Arch Bridge
Authors: Sun Guo Fu , Li Ji Hua
Published: October 2012

The steel tubular arch is hoisted segment by segment through cable crane and the stayed cables are used to maintain stability and balance. The determination of the stayed-cable forces and construction camber value of the erected rib segments becomes the key issue to ensure construction quality and safety. The forward iteration analysis method, which combines finite element method with optimization method as provided in this paper, can easily and effectively determine the stayed-cable forces and construction camber value in the erection of the rib segments, and the stay cables can be tensioned to their target force values only at one time. Finally, the example is demonstrated to prove the correctness and affectivity of the present method. Numerical example indicates that the results based on the method may be used to the backward analysis of the initial state, and that the proposed CM has excellent features of quick convergence rate and best global performance.
The Instability Analysis and Processing Scheme of ChangXin Viaduct Abutment
Authors: Wang Wen Hua , Zhao Wen Ding , Kong Xiang Li
Published: October 2012

In order to solve the abutment instability problem of the ChangXin Viaduct in JiLin to YanJi highway, we had the detailed geology survey and exploration of the abutment and its back roadbed, and had also the test of soil bulk density and the shear strength, and the deformation monitoring. The results show that the groundwater runoff and seepage functions for the abutment and its back roadbed are both strong because they are in the slope which in the junction of large diameter group sandstone and mudstone. Because of the two months consecutive rain function, the group stratum became soft in water, and added the combined function of the abutment and its back filled soil, so caused this group stratum sliding under the abutment and its back subgrade, and led to the abutment instability. To prevent the continuing landslide development, and maintain the landslide stability and the security of the bridges and roadbed, according to the causes above, we took the following treatment measures: Dismantling the finished 0th abutment and 1st pier, increasing two holes bridges, so making the abutment away from the landslide area, and at the same time transforming the extending foundation form to pile foundation, so they can reduce the damage function to the original slope body; Appropriately cutting earthwork and lessening weight of the landslide, using antiskid pile supporting baffle in the landslide body, and adopting blind ditch and cutting, drainage ditch to process drainage treatment, all of these ensure the stability of landslide and no adverse effects on bridge foundation.
Fatigue Assessment of Suspension Bridges Carrying Rail and Road Traffic Based on SHMS
Authors: Chen Zhi Wei , Xu You Lin , Wong Kai Yuen
Published: October 2012

Many long-span suspension bridges have been built around the world, and many of them carry both of rail and road traffic. Fatigue assessment shall be performed to ensure the safety and functionality of these bridges. This paper first briefly introduces the main procedure of fatigue assessment recommended by British Standard, and then it is applied to the Tsing Ma suspension bridge in Hong Kong. Vehicle spectrum of trains and road vehicles are investigated based on the measurement data of trains and road vehicles recorded by the Structural Health Monitoring System (SHMS) installed on the bridge so that fatigue damage assessment will be more realistic and accurate. Stress influence lines corresponding to railway tracks and highway lanes are established based on a complex finite element bridge model so that an accurate vehicle-induced stress response can be estimated based on them. The fatigue-critical locations for different type of bridge components are identified in terms of the maximum stress range due to a standard train running over the bridge. Finally, the fatigue life at the fatigue-critical locations due to both trains and road vehicles are estimated, and the result indicates the bridge is in very good condition.
Study on a Calculation Method of Critical Embankment Height on Natural Soft Foundation Considering the Effect of Crust Layer
Authors: Zhu Fu , Zhan Gao Feng , Nie Lei
Published: October 2012

Taking into consideration both stress dispersion effect and shear strength of crust layer, based on Flamant formula of polar coordinates representation and Mohr-Coulomb strength criterion, this paper deduces a new formula of critical edge pressure of natural soft foundation considering the realistic coefficient of lateral earth pressure. A calculation method of critical embankment height on natural soft foundation is proposed. The limit value of the result calculated by the new method is also put forward, which can ensure the reliability of the method applied. Additionally, critical embankment height at different thickness of crust layer h2, width of embankment loading B, soft layer soil coefficient of lateral earth pressure K0, crust layer soil coefficient of lateral earth pressure K1 is studied. Researches discover that the change of h2, B and K0 has significant influences on critical embankment height; a calculation result of critical embankment height is significantly partially high when the coefficient of lateral earth pressure is equal to 1 under this assumption.
Application of the Track-Cable Erecting System for Steel Truss Girder in Aizhai Suspension Bridge
Authors: Deng Nian Chun , Liu Xian Hui , Zhang Nian Lai , Wu Liu Yi
Published: October 2012

Aizhai Bridge is a stiffening steel truss girder suspension bridge and the main bridge consists of three spans of 242m+1176m+116m. It flies over Dehang Canyon, which is cliffy and steep, the depth between the designed elevation and the ground is 355 meters. In order to overcome the problems happened during the transportation, a new construction plan for the erection of steel truss girder is developed, combining the lifting technology with the cable-tracking transportation. Simply speaking, main cables and hangers are used as bearing structure, the track cables hanged on the hangers are used as transportation track. The transport vehicles system run along the tracking cables to deliver the steel truss girder, and the deck unit erecting system do the lifting job. In this paper, the scale model experiment and full scale model test of the track-cable transferring system are introduced, the design and test of erection gantry for deck unit are described. Finally, the engineering application of the track-cable erecting system is described. The results of experiment and engineering application show that the transportation and erection work of steel truss girder can quickly be completed by using the new construction plan. It is safe and economic solution, and has very broad prospect and practical value for the construction of suspension bridge and arch bridge.
Test Studyed of Yangjiawan Grand Bridge in the Project of Lanyu Railway by Movable Bed Model
Authors: He Wen She , Yuan Long , Chang Shuang Mei , Feng Jing Jing , Wang Liang Ming
Published: October 2012

Yangjiawan grand bridge is located in Lanzhou section of the Yellow River. In order to study the change laws near the bridge site of flow direction, velocity distribution, water surface slope, backwater area, river bed topography change and the effect of flood control on Lanzhou city after the bridge-built when the river gets through the average discharge, 20-year discharge, and 100-year discharge before and after the bridge-built. Based on the similar principle of model, the river near the bridge site was simulated by the hydraulic model experiment of movable bed. The result of experiment showed that the design data adopted in bridge project of Yangjiawan grand bridge were reasonable and fulfilled the requirements of city flood control. It was also suggested to excavate and dredge river near the piers of 6# ~11# and strengthen embankment near the riverbank and protection of constructions after the bridge-built.
Tests before and after Reinforcement of Tujiazui Bridge
Authors: Chen Xu Yong
Published: October 2012

This paper is aimed to verify the effects of reinforcement by tests before and after reinforcement of a two-way curved arch bridge with a clear span of 70m. Four 100kN and 180kN trucks are used for load tests of the bridge before and after reinforcement, and then the test values are compared with the calculated values. Tests before reinforcement has proved insufficient rigidity in some parts of the bridge, the design load grade is low, and the common fault in two-way curved arch bridges. The finite element numerical analysis tool ANSYS is used for finite element simulative analysis of the bridge, and the comparison of test values with calculated values shows the bridge can meet the existing design load grade after reinforcement. This paper has verified the feasibility and rationality of utilizing the physical unit of ANSYS for analysis of two-way curved arch bridges after reinforcement, and meanwhile, proved that the rigidity and design grade of bridges can be improved by reinforcement.
The Shear-Lag Effect on Curved Box Girder Bridge Considering Prestress and Initial Curvature
Authors: Qiao Jin Li , Jin Yong , Tian Wen Ling , Chen Xiang Shang , Du Chuang , Gao Shu Ling
Published: October 2012

According to the principle of minimum potential energy and energy differential methods and assuming the shear lag warp displacement function with consideration of prestressed steel, a set of differential equations are deduced with different boundary conditions in considering moment, torsion, shear lag coupling. And the numerical solution of the differential equations is gained by Galerlein method. In addition, explores the influence on shear lag with prestressed force or not, dead loading, live loading and prestressed forces of the prestessed steels the areas of them basing on the model experiment and finite element model. Comparisons of results for typical numerical examples are given to verify the accuracy and applicability of the present method.
Finite Element Analysis Simulation of the South-to-North Water Diversion Bridge during Cantilever Construction
Authors: Ma Hua
Published: October 2012

Use the Finite Element Analysis software to numerically simulate the South-to-North Water Diversion Bridge, a prestressed concrete composite box-girder bridge with corrugated steel webs, during the process of cantilever construction. Then research the force condition of the main girder structure during the construction processes. Results indicated that, during each construction process, the bending moment was reasonable, and all sections of the main girder structure were under pressure. The maximum normal stress always appeared around those cross-sections over the main piers, and during the mid-span closure process, the maximum stress appeared around the mid-span segment’s bottom flange.
Random Seismic Response Analysis of Long-Span Bridge Structures
Authors: Liu Zhang Jun , Xing Yan Fu , Wan Yong
Published: October 2012

Based on the orthogonal expansion method of stochastic processes, seismic acceleration processes can be represented as a linear combination of deterministic functions modulated by a set of mutually independent random variables. In conjunction with the probability density evolution method, the random seismic response of bridge structures can be successfully researched. A long-span bridge structure is taken as an example. The probabilistic information of the response of a long-span bridge structure in different control under earthquake excitations is investigated. The investigation provides a new approach to the random seismic response analysis of long-span bridge structures.
Research on Safety Accidents in Bridge Construction Based on Safety Rheology and Mutation
Authors: Wang Peng , Yang Wei Jun
Published: October 2012

The common safety accidents in bridge construction were according to safety rheology and mutation.The paper got the physics model and mathematical model of some common safety accidents that sky diving ,object striking and collapsing by safety rheology and mutation. It can be used to analyse safety accidents in bridge well.
Fire Safety Design Methods of Steel Bridges
Authors: Lin Hui , Meng Shu Tao , Luo Chun Hui , Chen Jun
Published: October 2012

Fire accidents are dangerous and uncertain. The steel bridges are particularly serious fire threat due to the steel own shortcomings. Steel bridges in the planning, design and operation need a complete set of fire relief measures. For steel bridges, the paper presents fire safety, fire loss distribution function and fire safety design. For a steel bridge, the paper presents specific fire safety measures and rescue processes.
Effect of Fly Ash on Creep of High Performance Concrete Used in Bridge
Authors: Zhang Liang Liang , Wu Li Qun , Yang Jian Xin , Zhang Kang
Published: October 2012

W/C ratio and the quantity of fly ash added have obvious influence on creep of high performance concrete. Effect of different quantities of fly ash on creep of high performance concrete of different W/C ratios used in bridge is studied in this research whose results reflect that creep value reduces along with reduction of W/C ratio at a certain quantity of fly ash added. Adding fly ash restrains creep on the whole, however, the degree depends on the quantity of fly ash added. Creep value of high performance concrete mixed with class-I fly ash at blend ratio of 12~40% is lower than that of standard concrete and fly ash at blend ratio of 18% has the best effect. Creep value in 365d is 51% of that of standard concrete at fly ash blend ratio of 18%, while at fly ash blend ratio of 40%, creep value in 365d is lower than that of standard concrete but higher than that of concrete at other blend ratios. It is generally considered that inhibition of creep of high performance concrete begins to fall beyond blend ratio of 30%.
Test Investigation on Mechanical of Unsaturated Loess
Authors: Zhu Yan , Chen Yun Xu
Published: October 2012

Compression and collapse of unsaturated compacted loess are studied by using dry density and water content which easily controlled in engineering, the controlling range of dry density and water content are confirmed respectively. Then the deformation of compression and collapse and the frequency of engineering damager occurrence can be decreased. In addition, the mechanical characteristics of loess in different directions may differ because the loess was consolidated only under the condition of its upper weight of soil and load. The conventional mechanical experiments, including one-dimensional compress and collapse test, were conducted with the specimen of loess soil in different angle from the original horizontal plane. The test result shows that the loess is anisotropic
Research on FLAC 3D Numerical Simulation of Working Mechanism of Compaction Pile Composite Foundation
Authors: He Yong Qiang , Zhang Hui Qing , Liu Bin Can , Wu Yun
Published: October 2012

Compaction piles is one of the conventional methods for foundation treatment in collapsible loess, there are very few research results about soil compaction effect between piles when forming the piles. Firstly, the stress field and displacement field of soil around compaction piles are elastic-plastic analyzed on the basis of the cavity expansion theory; then a series of FLAC 3D numerical simulations were performed to evaluate the treatment effect of the compaction pile composite foundation. The result shows that all bearing capacity has improved, and quicklime compaction pile composite foundation has been increased remarkably. It embodies the correctness of the computation theory. And the feasibility of the compaction piles composite foundation on collapsible loess area is further proved.
Research on the Measures to Improve the Durability of Urban Concrete Bridges in Hebei Province
Authors: Zhu Shou Qin , Bi Quan Chao , Cui Hong Huan
Published: October 2012

As one of the important traffic facilities in cities,bridges provide necessary services for the traffic in cities, but bridges that have been built in cities do not meet the requirements in durability aspect. We conduct a study about the durability of urban concrete bridges in Hebei province by this paper. In combination with the specific conditions of bridge construction, we put forward feasible measures to improve the durability of urban bridge for directiving the design and construction of bridges.