bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Rock Salt Dissolving Characteristics without Stress Effect
Authors: Tang Yan Chun , Fang Jing Nian , Zhou Hui
Published: May 2011

Through a lot of rock salt dissolving characteristics tests without stress effect, rock salt dissolving model without stress effect has been studied. The variation of shape of rock salt solid surface has been controlled by rock salt dissolving process directly, and rock salt dissolving model without stress effect can be built by the process of exchange of materials in dissolved boundary layer; through rock salt dissolving characteristics test without stress effect under different concentration, the computing equation by dissolved mass per unit area and concentration and dissolving time has been obtained; depended on the result of test and rock salt dissolving model without stress effect, the value of diffusion coefficient of rock salt has been computed. The achieved results on this paper can provide a foundation for the further analyses of rock salt dissolving characteristics with stress effect.
A New Direct Tension Machine and its Application
Authors: Zhao Zhong Hu
Published: May 2011

In order to improve the efficiency of the direct testing machine for rock tension experiments, a new elastic foundation of lower clamper is used to replace the original rigid one. By using this direct tension machine, the complete stress-strain tensile curve of rocks sample was obtained, and the rock mechanical property was studied with this experimental result. Basing comparing the experimental result between the indirect and direct tension experiment, the authors recommend it may obtain the mechanical parameters by direct tension test as well.
Progress of the Durability of Concrete Structure of the Subway
Authors: Wu Min Qin
Published: May 2011

More problem about the corrosion of concrete structures in subway engineering at home and abroad has been reported, people have analyzed that many factors have caused the corrosion of its concrete structure according to environmental characteristics and the location, such as the stray current and chloride ion and so on.we have reviewed the current research of the corrosion of concrete structures in subway engineering concerned on stray current and chloride ion, pointing out the direction of the study of corrosion of concrete structures in subway engineering.
A Study on Smelting Cold Heading Steel SWRCH6A Using Double-Slag Process
Authors: Wang Hai Chuan , Sun Wei , Wang Jian Jun , Lie Jie , Wang Kai Zhong , Wu Jian
Published: May 2011

The paper carries out a study on the composition control of smelting low-carbon low-silicon and high-aluminum cold heading steel SWRCH6A using double-slag process for converter at No.3 General Plant of Steelmaking & Rolling of Masteel, analyzes carbon increasing and silicon increasing status in each smelting process, and studies the mechanical properties, microstructure and inclusion ratings of test steel samples. These results indicate that in smelting process the average carbon increasing △w[C]=0.014%, the average silicon increasing △w[Si]=0.030%, the average content w[Al]s is 0.030% and w[Al]s fluctuates from 0.015% to 0.041%,, but all targets of test steel samples meet the requirements of cold heading steel SWRCH6A.
A Method for Determining the Value of m Based on PLAXIS Nonlinear Finite Element Analysis
Authors: Gui Jin Song , Li Zhen Guo , Meng Qing , Zhang Bo
Published: May 2011

The value selection of m has a greater influence on the internal force of pile. So, how to determine the value of m is very important for the “m” method. In this paper, a geotechnical finite element software PLAXIS is used for the nonlinear finite element analysis of elastic long pile under the horizontal force action. By using the calculated maximum bending moment and the maximum displacement at the ground, and combined with the related formula for “m” method given in 《Code for Pile Foundation of Harbour Engineering》, a more accurate value of m can be obtained conveniently. Because this method is simple and practical, it can provide a useful reference for the project designer to determine a reasonable value of m.
Finite Element Program Design of Bridge Structures with Internal and External Prestressing
Authors: Sun Jian Yuan , Yuan Yi Chao , Li Kun Peng
Published: May 2011

Recently internal and external prestressing enjoys a booming in the bridge construction, but the existing structural analysis programs of bridge can’t meet the requirements of analyzing the internal and external prestressing comprehensively. This paper will simulate internal and external prestressing effects by the finite element method; come up with some programming methods based on the object-oriented thought; and put forward the design and implementation methods of internal and external prestressing effect class by abstracting them to the corresponding class and elaborating the main features of each class, including the instantiation object and the typical method, to realizing the internal and external prestressing effects calculating. All of these will provide some references to the development of structural analysis program of bridge.
Cushion Impact on Bearing Capacity Exerting Degree of Soil between Piles for Rammed Cement-Soil Pile Composite Foundation
Authors: Guo Zhong Xian , Liu Jun , Qi Yong Shun
Published: May 2011

Basing on filed loading test results, the influences of cushion stiffness to the playing process of pile head and soil surface pressure in composite foundation was analyzed. Cushion stiffness will affect bearing capacity and failure mode of composite foundation with rammed soil-cement pile, which is applied in a relatively good ground. It point out that the cushion stiffness must be considered when loading test used to determine the bearing capacity of composite foundation with rammed soil-cement pile.
The Eigenfrequency Analysis of a 3D Fluid-Structure Acoustic Vibration with Numerical and Experimental Simulations
Authors: Yang Zhi Xi
Published: May 2011

The finite element method and modal synthesis method for the fluid-structure acoustic vibration in 3D problems is introduced in this paper. The coupled finite element procedure is implemented for 2D and 3D structures based on the displacement formulations for continuum elastodynamics, and the FFT and modal synthesis analysis for actual physical model is conducted for comparison. The experimental results illustrate a practical performance of the eigenfrequency analysis for lower order modes of the fluid-structure nondestructive evaluations.
Study on Confined Consolidation Test of Natural Loess
Authors: Kong De Quan , Wan Rong
Published: May 2011

The main object of study is the natural loess. The confined compression test and confined compression resilience test of nature loess and remolded loess under nature water content condition was done separately by using unsaturated high pressure consolidation apparatus. Through comparisons of test data, we investigated the effects of overconsolidated and structural factors on the loess compressibility under specific moisture conditions and analyzed the natural laws of compressive deformation properties of loess.
Influence of Cooling Methods and Standing Time on Different Aggregate Concrete Strengths after Elevated Temperature
Authors: Zhang Qian Qian , Yuan Guang Lin , Dong Ya Nan
Published: May 2011

After heated to high temperature, the strength test of concrete cube specimens made by siliceous and calcareous coarse aggregates was carried out. We analyzed the influence of cooling methods and standing time on concrete compressive strength respectively. The test results show that the compressive strength is generally decreased with increase in temperature. The relative residual strength of calcareous aggregate concrete is higher than siliceous aggregate concrete at higher temperature, so siliceous aggregate concrete has more significant fire resistance than calcareous aggregate concrete. Between 200°C and 550°C, the cooling methods have a great influence on concrete strength. The minimum of concrete strength appears at the 28th day after elevated temperature for both calcareous aggregate concrete and siliceous aggregate concrete in air cooling condition, whereas the minimum appears at the first week in water cooling condition. In addition, concrete strength values become steady with the lapse of time after the fire.
The Control Technology on Continuing Displacement of Tunnel in Coal Seam with High Stress Surrounding Rocks
Authors: Lu Ming Xin , Li Zhen Guo , Tian Yin Tong , Song Ping , Huai Yan Sen , Lin Tian Ye , Liu Chun Yu , Tong De Zheng , Qiao Shu Pei
Published: May 2011

The measurement data indicates that the main reason for tunnel damage is continuing level displacement with the characteristic of Pie Form. The experiment shows that, compared with uniaxial compressing, the residual stress in triaxiality compressing is greater, this can result that the level support can increase the stress of the surrounding rocks and decrease or stop the level displacement, at same time, control the pie form displacement of the coal. Based on the situation of tunnel displacement, semi-closing support with I bar or support structure with anchor cable are designed, which can control the continuing displacement of tunnel effectively.
Study on Searching the Best Rise of Truss String Structure by Using Fibonacci Method
Authors: Zhou Hai Bo , Liu Ping , Hou Guan Ze
Published: May 2011

In order to discuss the relationship between truss string structure weight and the rise, so as to find out the optimal rise of different spans, Fibonacci search method is used to write truss string structure optimization program which takes the rise as variable. To effectively improve search efficiency and ensure the accuracy, the dynamic search interval is introduced when writing the Fibonacci search program. This paper use Fibonacci to search the optimal rise in span of 100m of truss string structure, meanwhile analysis the dynamic search interval, the analysis results show that the approximate solutions of this method is very approximate to exact solutions, and search efficiency is improved.
Experimental Study on Compressive Bearing Capacity of Disk Pile under the Influence of Horizontal Load
Authors: Meng Fan Li , Zhai Xiao Peng , Lu Chen Yuan
Published: May 2011

Two groups of model pile tests was designed to study the influence of horizontal load on compressive bearing capacity of different types of pile. Experiment showed that the existence of horizontal load at the pile top had large influence on the bearing capacity of equal-diameter piles and single-disk piles with the disk being set at the upper of pile, but little influence on double-disk piles with the disk also being set at the upper of pile. It illustrated that the disk being set at the upper of multi-disk pile has better effect on the resistance to horizontal load.
Study on the Relationship between Stress-Deformation and Space-Time in Hejiagou Tunnel Construction
Authors: Fu Le , Li Qian , Qiao Lan , Li Zhi Qing
Published: May 2011

Based on the technological features of highway tunnel information design and construction，the relationships between stress-deformation and space-time were studied profoundly, combining closely to the monitoring practice of Heijiagou highway tunnel in Beijing to Chengde express way. With the results in rock mass stress monitoring, the adjustment law of stress was analyzed; and the relationships among stress and rock mass classification, burial depth and geologic conditions were disclosed. A profound study about the features of the relationship between rock mass deformation and space-time was carried out, as well. Finally, the application of monitoring results on rock mass classification, hazard forecasting and determination of the best time to construct the secondary supporting was introduced.
Study on Destructive Modes of RC Frame Columns in Wenchuan Earthquake
Authors: Liu Cheng Qing , Shi Wei Xing , Zhao Shi Chun , Pan Yi
Published: May 2011

Typical earthquake damages of Reinforced concrete columns in the Wenchuan earthquake are introduced, and the damage characteristics of concrete columns are described, then several typical destructive modes of Reinforced concrete columns are summarized. Further, various reasons of destructive modes are analyzed. Final, some practical advices are proposed to reduce the damages of reinforced concrete columns.
Cause Analysis of the Dangerous Factors in Construction Accidents and their Countermeasures
Authors: Su Zhao Gui , Jiang Zhong An , Dong Wen Geng
Published: May 2011

Aiming at the building in city, the dangerous sources in construction are analyzed. Some hazardous factors, which are fountains of the accidents, are certainly made. By accidental types analyzed, accident positions analyzed and accident-engineering sorts analyzed; the complexity and authenticity of accident sources in construction can be distinctly set forth. Some safety control measures are made, which can be used to reduce accidents and advance whole safety supervising level in construction.
Calculation of the Interfacial Tensile Stress of CFST Members under Axial Pressure
Authors: Huang Yong Hui , Wang Rong Hui , Huang Xiao Feng
Published: May 2011

Based on plane strain theory, the formula for calculating the tensile stress on the interface between the steel tube and concrete under the axial pressure was derived, and the stress distribution coefficient K was analyzed. Practical formula for calculating the interfacial tensile stress of CFST members under low stress condition was fitted. Using the fitted formula the interfacial stress calculation process can be greatly simplified, and the results have enough assurance. This formula can be easily applied to CFST members’ interfacial stress calculation.
Experimental Research on the Dynamic Young’s Modulus of Specified Density Concrete
Authors: Zhou Xiao Er , Zhang Yan Kun , Jiang De Min
Published: May 2011

From the experimental research, the relations between the dynamic modulus of elasticity and natural vibration frequency of specified density concrete are studied, the static Young’s modulus and dynamic modulus are compared. Based on regression analysis, the influence of different Substitution ratio of lightweight aggregate, age of concrete and cement water ratio is studied. According to the test results, the formula of natural vibration frequency and the dynamic modulus of elasticity of Specified density concrete is given, which provide theory basis for the nondestructive detector of the specified density concrete.
Analytical Hierarchy Process Applied to Risk Analysis of Deep Excavation
Authors: Zhang Jiao
Published: May 2011

The application of the analytical hierarchy process (AHP) to the risk analysis of deep excavation was investigated. Firstly, the occurring probabilities of various risk factors during deep excavation were calculated. Secondly, the aftereffects of the risks were concluded by consulting the experts. Thirdly, the weight of each risk factor was obtained by AHP. Finally, the total risk of deep excavation could be evaluated by fuzzy complex evaluation. This risk analysis method was applied to evaluate the total risk of a real deep excavation, and the exemplification verified its feasibility.
Experimental Study on Bond-Slip between Steel Bar and Recycled Aggregate Concrete
Authors: Huang Qing Feng , Wang Da Fu
Published: May 2011

By a static and repeated pull-out experiment between steel bar and recycled aggregate concrete, and bond-slip curves between recycled concrete with different recycled coarse aggregate(RCA) replacement percentages were recorded. Based on the analysis of the experimental results, replacement percentages of recycled concrete, cover thickness, anchorage length, concrete strength and loading method was investigated. At last, the bond-slip constitutive relation was also discussed.
Finite Element Analysis on Mechanical Properties of Light-Weight Aggregate Concrete Composite Slab
Authors: Zhang Yan Kun , Zhang Shao Yu , Zhou Xiao Er
Published: May 2011

By finite element method, experimental results of the light-weight aggregate concrete composite slab are compared with the numerical simulation.. On the basis, nine composite slab specimen are designed. The loading process, includes the slab cracking, the yielding of steel plates, damaging of slabs are simulated, and the influencing factors, such as male pin, thickness of deck, and spacing of transverse shear reinforcing bars, etc. is studied. At last, the spacing of transverse shear reinforcing bars of light-weight aggregate concrete composite slab is given, and it is useful to the engineering design.
Response of Soil Suction to Heavy Rainfalls in a Tailings Dam
Authors: Chen Rui , Zhang Ben Zhuo , Lei Wei Dong , Luo Wen Bin
Published: May 2011

Rainfall is a significant factor leading to failure of tailings dams. The impact of rainfall on the instability of dams is mainly reflected in the variation of negative pore-water pressure (i.e. matric suction) during rainfall infiltration. However, there is a lack of study on the effects of rainfall on suction in tailings dams. In this study, the response of suction to artificial heavy rainfalls in a tailings dam was investigated. The effects of rainfall intensity and surface vegetation conditions on the response of suction were studied. It is found that suctions at a certain depth in the tailing dam were kept constant until the wetting front reached this depth. Once suctions were altered, the values dropped rapidly. The magnitude of suction change generally decreased with depth. Rainfall infiltration mainly occurred above the depth of 40 to 80 cm when subjected to rainstorm and heavy rainstorms. Larger rainfall intensity leads to shorter response time and to larger depth affected by rainfall, implying that the tailings dam is more susceptible to shallow landslide failure under larger rainfall intensity. The existing vegetation increases infiltrability significantly and then produces an adverse effect on the stability of the tailings dam. On the other hand, it is observed that the presence of vegetation greatly prevented surface erodibility and then decreases the possibility of debris flow.
Internal Force Analyzing of Plane Frame Structure Based on Interaction Theory
Authors: Chen Xiang , Hou Wei
Published: May 2011

Based on researchers of interaction theory and its application, mechanism of interaction among superstructure, base and foundation was analyzed and a design method was proposed. Combining with engineering construction cases, change law of internal force of superstructure in interaction system was researched through comparing results between interaction analyzing method and custom computation method. Some meaningful engineering design devices were concluded finally.
Behavior of Reinforced Concrete Columns with ‘T’-Shaped Cross Section after Exposure to Fire
Authors: Xu Yu Ye , Wu Bo , Wang Rong Hui , Jiang Ming
Published: May 2011

The residual strength of reinforced concrete (RC) columns with ‘T’-shaped cross section after fire are decreased more quickly than those of RC columns with rectangular cross section for the former have thinner sectional thickness and larger surface area. The influence of several main parameters, such as exposure times, effective lengths, sectional dimensions, load eccentricity ratios, reinforcement ratios, load angles and longitudinal reinforcement yield strength on the residual strength of RC columns with ‘T’-shaped cross section after exposure to fire was investigated. A self-developed finite element program CAFIRE was applied in this study. 24300 hypothetical cases of columns after subjected to fire on all sides were selected for residual strength analysis. Different fire exposure times, effective lengths, cross section dimensions, load eccentricity ratios, reinforcement ratios, load angles and longitudinal reinforcement yield strength were considered in the analyses. Based on the simulation results, a practical method was proposed for calculating the residual strength of columns with ‘T’-shaped cross section after subjected to fire on all sides. The simulation results indicate that: (a) the residual strength of columns with ‘T’-shaped cross section decreases linearly with the increase of effective length, but it increases linearly with sectional width, ratio of sectional height to sectional width, and yield strength of longitudinal reinforcement strength; (b) the residual strength of ‘T’-shaped columns decreases markedly for a load eccentricity ratio in the range of 0.0 to 1.0, whereas it varies slightly for a load eccentricity ratio between 1.0 and 3.0.
Study on Capillarity Water Rise in Subgrade Soil
Authors: Deng Yun Chao , Hao Pei Wen , He Lei
Published: May 2011

Many highways in China cross irrigation area of farm land. The water in rivers and ponds by two sides of roads can flush back into subgrade, and results in more water in subgrade soil, subgrade deformation and lowered capacity. With reconstruction and extension of Zhengzhou-Luohe segment in Jing–Zhu Highway as the research target, this study investigated the method for preventing underground water from entering subgrade. Through studying on capillarity water rise in typical soil of Zhengzhou–Luohe segment, we found out water rise pattern, predicted capillarity water rise and obtained the method for preventing capillarity water from rising into subgrade.
Accelerated Carbonation Curing of Foam Concrete with Lower Density
Authors: Chen De Ping , Liu Jing Yu , Liu Min
Published: May 2011

Carbonation curing was adopted to accelerate the hydration of foam concrete with lower density of around 450 kg/m3. After standard curing in mold for 2d, the foam concrete samples were marked into two groups. The first one is directly cured in ‘Carbonation Test Chamber for Concrete’ with CO2 concentration 20%, RH 70% and temperature 20°C (it was called ‘carbonation curing’) for 3d to 56d. The second one is cured in ‘Standard Curing Room for Concrete’ with RH ≥95% and temperature 20°C (it was called ‘standard curing’) for 7d, and then at carbonation curing for 3d, 7d and 21d. The strengths of harden foam concrete were tested, the hydration products were analyzed by means of XRD and TG/DSC. The results were compared with those of standard curing samples. It indicates that foam concrete with lower density is easier to be carbonated; the hydration of both C3S and C2S accelerates by carbonation curing, which results in higher early strength improvement. Vaterite is popular in the second group of samples, while it only appears in the first group of sample with longer carbonation time of 56d. Vaterite was considered to be formed from the further carbonation of CxSHy.
Theoretical Analysis of SSCC Floor System of through Truss High-Speed Railway Bridges
Authors: Zhang Ye Zhi , Chen Liang
Published: May 2011

In SSCC floor systems the concrete slab is composite with both steel stringers and crossbeams or only with stringers. The horizontal bending of the crossbeams of SSCC floor systems is not ignorable. From the deformation conforming condition, theoretical formulas for SSCC floor systems of double-railway bridges with two stringers are developed. The factors which influence the horizontal bending of crossbeams are discussed. Some conclusions are obtained. When the width of the SSCC floor system is given, the main factors which influence the horizontal bending of the crossbeams are the axial stress of the lower chords, the distance between the side stringers and the lower chords, and the continuous length of SSCC floor system. Increasing the horizontal inertia moment of crossbeams almost cannot reduce the horizontal bending stress of crossbeams. A slight horizontal rotation of the lower joints such as 10-4 rad can release more than 3% crossbeam end horizontal bending moment.
The Impact Analysis of Grouting Effects to the Settlement of Subway Tunnel Construction
Authors: Ding Wen Long , Liu Tao
Published: May 2011

For subway tunnels such as Nanjing Metro II excavated by mining method, one of the most important reinforcement methods for preventing surface settlements is the grouting method. There are many soft and weak surrounding rocks and abundant groundwater in the metro section, so grouting has become a major method in reinforcing the fragmented rocks and soil. But bad grouting support caused by fluid loss in soil and rock often allows uncontrollable settlement. In order to analyze the differences in grouting techniques, combined with the actual excavation process and the contrast of different means of settlement control in a complex section of Metro II, this paper adopts the numerical simulation method of FLAC3D to demonstrate that strict management and proper methods can create good and dependable reinforcement of the unstable surrounding materials.
Study on the Maximal Critical Velocity of Pressurization in Subway Station
Authors: Zhong Wei , Yang Jian Peng , Pei Bao An , Gao Zi He
Published: May 2011

The prediction model of maximal critical velocity of pressurization was established theoretically by analyzed the pressure’s distribution in both sides of smoke bay. Using the computational fluid dynamics software FDS5.0 to build a 3D model of an island platform with platform edge door, Large Eddy Simulation model was used to obtain the critical velocity in different HRR, ceiling screen’s height and arrangement. Results show that the critical velocity rises with the increasing of HRR, and gradually reaching to the maximal critical velocity; in the range from 0 to 2m, it can be regarded that the maximal critical velocity is linear to ceiling screen’s height. The arrangement of ceiling screen has some influence on the critical velocity; setting ceiling screen around the staircase is more effective to restrict smoke.
Analysis of Influencing Factor of Super-Long Single Pile’s Effective Pile Length
Authors: Lai Tian Wen , Zhou Qi Yun
Published: May 2011

Taking Clough & Duncan’s hyperbolic model as the transfer function, the influencing factor of super-long single pile’s effective pile length are analyzed. Discussed four kinds factors, which are the pile elastic modulus Ep, the external friction angle σ, the material parameters k1 and the allowable settlement Sa, effect on the effective pile length. The conclusion has some active meaning to super-long single piles’ the theoretical study and the application to engineering.
Selection and Analysis on the Foundation of Long-Span Spatial Arch Structure
Authors: Xiong Xue Yu , Wang Yi
Published: May 2011

This subject studies the mutual effect between the upper structure and the foundation of the long-span spatial structure in the process of construction, normal use and carrying capacity. It compares different foundation forms which can withstand relatively large levels of thrust. The internal force analysis models of the most common form-prestressed tie rod are established and a systemic design theory about the long-span spatial arch space structure is formed. This subject fills the research gap on the foundation design of the long-span spatial arch structure.
Fractal Research on Cracks of Reinforced Concrete Beams with Different Aggregates Sizes
Authors: Sun Hong Quan , Ding Jun , Guo Jian , Fu Dong Liang
Published: May 2011

Under the concentrated loads, the crack evolutions of reinforced concrete experimental beams (RCEB) with three different aggregate sizes are studied. Using fractal theory, the generation, development and distribution of the cracks on the RCEB are analyzed. The results show that the cracks on the RCEB have fractal characteristics obviously. By studying the fractal dimension of the cracks, the aggregate sizes have significant effect to the cracks on the RCEB. The relationships of the fractal dimensions of the crack evolution in loading processing and loads meet the power function laws. The researching results of this paper provide a new theoretical basis for selecting the appropriate aggregate size to improve the strength of reinforced concrete beams.
Recovery Execution in Landslide at the Portal of Highway Tunnel
Authors: Wang Kai , Kang Hai Gui , Wang Hai Tao
Published: May 2011

The main feature of NATM is to utilize all available means to develop the maximum self-supporting capacity of the surrounding rock or soil itself, and to undertake investigation and monitoring during construction to provide the stability of the tunnel. If undetected worse ground condition is encountered, the strengthening works will be carried out to ensure safety. In this case study, taking the Wangkeng tunnel portal engineering of the Jiyuan-Shaoyuan Expressway in Henan Province as an example, the calculation and evaluation of landslide stability are performed by limit equilibrium method and FEM. Based on the results of stability analysis, the anti-slide piles and ground drainage are adopted as the harnessing measures of landslide. Comparison of stability analysis before/after landslide harnesses was made by FEM. The results show that these treatments can satisfy the design requirements. It could be a useful reference to the design and construction of tunnels with soil entrance.
Simulation Analysis of Surface Deformation by Strip Replacement Mining in the Short-Distance Thin Coal Seam
Authors: Zhang Pei Sen , Yan Wei , Zhang Wen Quan
Published: May 2011

The strip replacement mining in short-distance thin coal seam is one of the effective methods controlling displacement deformation of overlying strata and surface subsidence in coal mining under buildings and railroads and water bodies. The method has a great theoretical significance and application value by increasing recovery rate of coal resources and cutting down the effect of coal mining on environment and surface of mining area. The numerical simulation method is adopted to study the surface deformation characteristics by the strip replacement mining in short-distance thin coal seam. Such conclusions are drawn as follows: the strip project of forty meters mining with forty meters reserving is quite suitably selected while half of mining rate; ten meters in replacement width of coal pillar is relatively optimum; the feasibility of the strip replacement mining technology is verified by the simulation. Therefore, the strip replacement mining technology has provided one kind of new thought to coal mining under buildings and railroads and water bodies.
Research on the Vibration Attenuation Rules and Wave Propagation Law under Impacting Drill on the Deep Soil Layer
Authors: Zhang Bo , Tao Lian Jin , Wang Wen Pei , Li Ji Dong
Published: May 2011

A field test is carried out to study the effect of vibration while treating foundation using vibroflotation method in the deep soil layer in Zhengzhou, China. The vibration attenuation rules and wave propagation rules in different formations caused by different numbers of drills are analyzed. Evaluate the influence on the adjacent buildings. The result shows that the vibration will be generated in foundation obviously in the process of construction using the method. Vibration force, impact frequency and site soil are important influence factors on ground vibration attenuation. The analysis reveals that the maximum vertical acceleration attenuation velocity was much greater in near area than that in the relative far area. The waves caused by vibration propagate in two ways: (1) surface wave is generated on the wall of drill hole and propagated to the ground surface, and attenuated in a certain distance (<8m); (2) shear wave was generated and propagated in the impacting formation and attenuated from the deep formation to the ground surface. Vibration amplitude is mainly distributed in the low frequency range in the areas which far away from vibration source and in the silt layer near the ground surface.
Research on the Earthquake Dynamic Responses of Tunnel under Changing Tunnel Lining Rigidity
Authors: Cao Xiao Ping
Published: May 2011

With the increasing of the quantity of the tunnel, more and more attentions have been paid to the tunnel destruction induced by earthquake. Based on the software of finite element, the finite element model for deeply buried tunnel have been set up; and the responses about different rigidity of tunnel lining under seismic dynamic load has been analyzed by using elastic finite element theory. The conclusions have been drawn that the change of seismic responses by increasing rigidity of tunnel lining is unobvious, and the method using increasing rigidity of tunnel lining to reduce the seismic responses of tunnel is uneconomical.
Deformation and Internal Force Analysis of Deep Foundation Pit Excavation with Outrigger-Type Diaphragm Wall
Authors: Hu An Feng , Rao Hang , Yuan Jing
Published: May 2011

As a new technique of excavation support structures, outrigger-type diaphragm wall has got an application in deep pit engineering, though the design of its parameters still lacks theoretical guidance. Based on a large-scale deep pit case, a 3-D finite element model is presented to simulate the behavior of outrigger-type diaphragm wall using the software ABAQUS. The soil is assumed to behave as a modified Cam-clay model. The effect of the outrigger length on deformation and internal force of the supporting structure is studied. It is found that the basal heave ,the ground settlement and the horizontal displacements of the retaining wall will increase with the increase of the outrigger length, when the bottom elevation of the supporting structure keeps unchanged. When the outrigger length goes beyond a certain length, the rate of increasing becomes larger. In the outrigger-type diaphragm wall, the vertical stress of inside and outside wall approaches the maximum in the vicinity of the variable cross-section. At the same time, the variable cross-section produces a shear stress mutation because of the abrupt change of stiffness. There exists a reasonable length of the outrigger, which could meet not only the technical requirements of the supporting structure, but also the needs of saving the cost and reducing the difficulty during the construction.
Geological Expedition and Analysis on Formation and Evolvement of Erosive Karst Tiankeng: A Case Study of Xingwen World Geopark
Authors: Shui Wei , Wang Xing Gui
Published: May 2011

Erosive Karst Tiankeng has been a new type of Tiankeng Since the Collapsed Karst Tiankeng was found and primarily research by Zhu Xuewen, a famous geologist. But, how the Erosive Karst Tiankeng evolved and developed? How can we find the proofs on formation and evolutional processes of Erosive Karst Tiankeng? Few scholar focused on this new field. According to the first-hand datum by geological Expedition and study in Xingwen World Geopark, the results and datum show that apart from Dayanwan and Xiaoyanwan collapsed karst Tiankeng, there are other karst landforms in Bowang Mount scenic spot of Xingwen World Geopark such us Feiwu Cave, Dao Cave, Cangshuiyan Gorge, Nanxing TanKeng and so on. These typical karst landforms could be regarded as different vestiges of erosive karst Tiankeng of Xingwen World Geopark, which stand for the evolutional processes of erosive karst Tiankeng separately. Moreover, the evolutional processes of erosive karst Tiankeng could be divided into the following continuous processes: an erosive karst Tiankeng develops from the processes of eroding and dissolving & extending of silo Sinkhole, and subsequently degrades to a large gorge or doline. It is worth pointing out that except for erosion of flowing water, at the same time, collapse’s effect has been playing extremely important role in the forming processes of these special erosive landforms.
Simulation and Field Test for Local Acceleration of an U-Shaped Girder
Authors: Li Qi , Wu Ding Jun
Published: May 2011

The local vibration of a bridge under moving train is the source of low frequency noise radiated from the structure. Local vibration of bridges has not been widely studied compared to global vibration that leads to serviceability and safety problems. The local vibration of an urban rail transit U-shaped girder is simulated with the proposed mode superposition based train-track-bridge dynamic interaction model. The computed local acceleration responses under various train speeds are then verified by those obtained from field test, in terms of time-histories, spectra, peak-to-peak values and root mean square (RMS) values. It is founded that the main frequencies of the local acceleration of this girder are below 100 Hz. The proposed method and the computed local vibration could be further applied to predict the bridge-borne noise.
Research on Mechanical Properties of Molded Products Using Building Waste
Authors: Chen Ri Gao , Yao Yan , Wang Ling
Published: May 2011

Recycle utilization of building waste is the tendency of building material for environment protection & sustainable development. Mechanical properties of molded products using building waste (MPBW) were investigated. The main parameters are focus on molded pressure, dosage of building waste added into cement and fly ash. The results of experiments showed that molded products using concretes debris as fine aggregates have stronger mechanical properties. The strength of product increased along with molding pressure increase under 15MPa , but it was almost no increase when the molding pressure was up from 15MPa to 20MPa.The addition of building waste has little effect on the compressive strength of product when its dosage range from 50% to 100% .The strength of product had obviously changed after using fly ash partially substitute for cement, when fly ash replace two thirds cement, the product strength of 28d was 15.4MPa, and was still higher than that of the normal wall materials. Later strength of the product had markedly increased, its 180d compressive strength achieved 25.2MPa. Test results confirmed: using building waste, panel, block and other products with better mechanical properties could be manufactured by adjusting the molded pressure and the dosage of building waste and fly ash.
Safety Problems of Engineering Structures at the Ground Fracture Sites Taking Xian’s for the Example
Authors: Fu Guang Yao , Zeng Fan Sheng , Tian Min
Published: May 2011

The ground fracture already becomes one of main city's geological disasters in China, this geological disaster is quite serious in Xi'an, of Shaanxi province capital city. In this city the ground fracture growth is intense, the causes of the fracture are very complex, the building and engineering structures to be able to have the serious destruction where the fracture passed through its base. In China national civil engineering design codes, the method which designs about buildings on the site of ground fracture is the blank, only Shaanxi Province engineering construction standard gives some specifications for site investigation and engineering design to the Xi'an ground, use the measure that is get out of the way to the building destruction, and rules the smallest required safety distance. Discovers the security problem of the engineering structures located in the ground fracture site is a complex topic, the Shaanxi Provincial engineering design standards have some deficiencies in the theory aspect. Reckon it is necessary to systematically research this topic. These work include more widely and deeply to investigate the ground fractures activity, found the ground uneven settlement modes in fracture belt, and analyzes safe reliability of all kind of building structure on the fracture site, as well as, analyses structures seismic capability.
Corrosion Behavior of HRB400 Reinforcing Steel Using Cyclic Potentiodynamic Polarization Technique
Authors: Xu Yu Ye , Lin Bi Lan
Published: May 2011

HRB400 reinforcing steel due to high strength and high ductibility is as the main reinforcing steel in “Code for design of concrete structures (GB50010-2002)” in China. Cyclic potentiodynamic polarization technique was used to investigate the electrochemical corrosion bebavior of HRB400 reinforcing steel in Simulated Concrete Pore solutions (SCP solutions) differently contaminated by bicarbonate ions and/or chloride ions. The evolution feature of the corrosion parameters was analyzed and was compared with that of HPB235 reinforcing steel. The results show that the corrosion characteristics of HRB400 and HPB235 were exceedingly similar before the destruction of the passivation film. However, HRB400 is remarkedly more susceptible to chloride ions and carbonation than HPB235 during the failure of the passivation films. The pH threshold for HRB400 is larger than that for HPB235, and the chlorides threshold for the former is smaller than that of the latter. When HRB400 and HPB235 were connected and exposed to an aggressive environment, the galvanic corrosion will occur where HRB400 is anode and HPB235 is cathode. To ensure the durability of the reinforcing concrete structures, it is necessary to make the connection points insulate.
Research on Deformation Forecasting of Deep Foundation Pit Supporting Structure Based on BP Neural Networks
Authors: Xue Yi , Xu Lei , Cao Zheng Zheng
Published: May 2011

Excavation engineering is affected by many kinds of factors. It is becoming the key and difficult point in geotechnical engineering. This paper analyzes and predicts the deformation of supporting structure in urban deep excavation with artificial neural network theory, establishing network predictive model to predict the maximum deformation of supporting structure. The result shows that the network system has high precision, and it can be applied to practice.
Numerical Simulation and Field Test of Broken Zone in Geologic Unsymmetrically Loaded Tunnel
Authors: Jiang De Yi , Guo Wei , Zheng Yan Kui
Published: May 2011

In this paper, the ubiquitous-joint model was used to simulate the layer-rock and the development of broken zone with different excavation methods. The numerical results agree well with the results of field test which measured by ground-penetrating radar (GPR) in Gonghe tunnel on Chongqing-Changsha expressway. The change rules of broken rock zone in Gonghe tunnel and the optimal excavation method are discussed.
Numerical Simulation of Inclined Multi-Seam Mining Subsidence of Considered the Impact by Faults
Authors: Wu Zhi Ping , Qiu Sheng Hua , Li Ying
Published: May 2011

According to the complex mining geological condition of Shandong gentle inclined multi-seam mining, Use the three-dimensional finite element numerical analysis software to establish three-dimensional geological model under the different mining working conditions. Taking into account the impact of faults to calculate multi-seam roof strata movement and surface subsidence caused by the different mining working conditions. The level displacement & subsidence distribution curve of the reference point of surface & multi-seam roof strata under the different working conditions is shown. The maximum, minimum settlement, differential settlement and subsidence diagram is shown. And the principal stress, shear stress value of surface & multi-seam roof strata after mining also is shown. The results showed that: little change of the biggest surface subsidence and differential settlement is caused by mining 3101&3102 face or separate 3101 or 3102 face. And the largest subsidence, and the settlement difference of the surface is 520mm, 498mm, 515mm and 59mm, 78mm, 81mm, Respectively. It provides an reference for reasonable, safe, economic for the inclined multi-seam mining under similar conditions.
Semiactive Wind Response Control of 76-Story Benchmark Building with Smart Piezoelectric Friction Dampers
Authors: Dong Ping , Fan Jian
Published: May 2011

A smart piezoelectric friction damper (SPFD) is presented based on improved Pall friction dampers and its damping force model is analyzed. The wind-induced vibration control of Benchmark model using semi-active control strategies based on the classical LQR is studied. The results of simulation analysis show that the semi-active control effects of the standard wind-control model with SPFD is evident. Compared to uncontrolled structures, the wind-induced vibration responses of the controlled structures are effectively reduced. In addition, parameter optimization of the semi-active control system based on the limit Hrovat optimal control algorithm is carried out. The analysis shows that the robustness of the semi-active control system to the stiffness uncertainty of Benchmark Model is very good, but the robustness to the damping uncertainty is not so good.
Reinforcement Maintenance Method about Chinese Ancient Architectural Structure
Authors: Luo Shi Bao
Published: May 2011

According to the ancient wooden architectural features, the different destructions of wood structures are discussed. On the basis of the importance and principle of Chinese historic building reinforcement and maintenance, ancient architectural wood structure reinforcement is introduced. Finally several proposes about the Chinese historic building reinforcement maintenance is given.
Dynamic Response Analysis of Bridge Pier Subject to Earthquake and Ice Loads
Authors: Qi Fu Qiang
Published: May 2011

In order to discuss the effect of earthquake and dynamic ice loads to a bridge pier, this paper considered the effect of added mass of dynamic water, and it deduced the dynamic equilibrium equations for a bridge pier subject to earthquake and dynamic ice loads on the basis of nonlinear Morision equation. Using numerical analysis method, it discussed the dynamic response of a bridge pier subject to different types of earthquake loads, forced ice loads, and both earthquake and forced ice loads. Through comparing the pier responses in different work conditions, it discovered that the dynamic responses of the bridge pier subject to forced dynamic ice loads rise and fall severely at the time of ice buckling broken periodic change. The coupling effects of forced dynamic ice loads and earthquake especially near-fault earthquake enhance the dynamic response of bridge pier significantly.
Simple Method for Dynamic Interaction between Two Rigid Foundations
Authors: Yan Bin , Lv Ying Hui , Hu Ping
Published: May 2011

In the past many researchers studied dynamic stiffness and damping coefficients of surface and embedded rigid foundations of arbitrary shapes in the elastic homogenous half space. Dynamic stiffness and damping coefficients were obtained by using regularly shaped foundations instead of arbitrarily shaped ones. Obviously, the calculating methods were not perfect. In addition, the two parameters mentioned above were calculated only in the case of a single foundation. But the cases of two or more foundations were not presented because the interactions between foundations were not considered in all present papers. This paper eliminates two faults named above by using the assumption of the plane strain and of dynamic foundation-soil interaction factors. The calculating method of dynamic impedances presented by the paper proved to be accurate and practical.
Numerical Analysis of RC Shear Walls under Cyclic Loading by PERFORM-3D
Authors: Jiang Huan Jun , Liu Lao Er
Published: May 2011

For engineering practice purpose, the macroscopic model capable of simulating the main characteristics of nonlinear behavior is desirable to reduce computational efforts in nonlinear structural analysis. Several different types of macroscopic models for shear walls have been developed. The shear wall element used in the commercial program PERFORM-3D is one types of macroscopic models for reinforced concrete shear walls. The application of PERFORM-3D in the nonlinear static analysis of reinforced concrete shear walls is introduced in this study. The selection of constitutive models and the determination of related parameters of the constituent material are presented in detail. The applicability of the shear wall element is verified by numerical simulation on three reinforced concrete shear wall specimens under cyclic loading. The comparison between the numerical analysis and test results leads to the conclusion that the shear wall element with appropriate constitutive models can capture the nonlinear behavior of reinforced concrete shear wall well and be conveniently applied in engineering practice.