bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Crack Resistance of Roller Compacted Concrete（RCC）
Authors: Zeng Li , Wu Ding Yan , Zhang Yan Hua
Published: December 2010

A parameter of crack resistance Φ is proposed as an index to assess crack resistance of RCC comprehensively. The higher the value of Φis, the better crack resistance of RCC becomes, and it was tested and verified by indoor experiment. Meanwhile, time effect of the parameter is also studied deeply, and the characteristic of development of crack resistance is presented. Ф changes with the passage of the time. Its value decreases before 14 days, but increases after 14 days, and it is minimal at the age of 14 days, which means that crack probably exists. Finally, We improve crack resistance of RCC by improving transition zone and toughness of binding materials, optimizing aggregate and adding admixtures etc.
Local Buckling Analysis of Aluminum I Section Beams
Authors: Wang Yuan Qing , Yuan Huan Xin , Shi Yong Jiu , Cheng Ming
Published: December 2010

Low elastic modulus of aluminum alloy gives prominence to lateral and local buckling of members, especially when thin walled sections are adopted to save material usage. Under certain conditions of loads and constraint, local buckling would occur in aluminum beams. A numerical study to assess the local stability of aluminum I section beams is presented in this paper. The study focused on two aspects: the local buckling of aluminum flange plate under compression, the local buckling of aluminum web plate under bending and shear. An extensive parameter analysis including width-to-thickness ratio, initial imperfection, material constitutive relation and restriction effect from adjacent plates was carried out with the purpose of extracting several governing parameters and investigating their effects on the local buckling of aluminum plate. Based upon the results of finite element analysis (FEA), a new design method in connection with the local stability of aluminum I section beams has been developed. By virtue of the proposed design method, three key indicators that include the critical value of width-to-thickness ratio to prevent local buckling of aluminum flange plate under compression, the local stability of aluminum web plate under bending/shear and the bearing capacity of aluminum I section beams under the condition that the post buckling strength of web is taken into account, could be obtained to provide more rational and efficient designs. The proposed design method is different from the current Eurocode but acts in accordance with Chinese code for design of steel structures (Chinese steel code) in order to satisfy applicability.
Phase Evolutionary Process of CaO-Al2O3-SiO2 System Glass and Glass-Ceramic
Authors: He Feng , Ping Cai Ming , Cheng Jin Shu
Published: December 2010

Sintering glass-ceramics, a new type material for architectural decoration, belong to CaO-Al2O3-SiO2system (CAS) without nucleation agent. Combined by Differential thermal analysis (DTA), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscope (TEM), phase evolutionary process of CaO-Al2O3-SiO2system glass and glass-ceramic was investigated. According the relation between heat treatment schedule and microstructure, the glass system has a very wide temperature range of crystallization. The crystalline phase is β-CaSiO3(β-wollastonite) and there is no other crystalline phases precipitated in these glass-ceramics. The influences of various heat treatment systems on the structure and properties of the glass-ceramics were investigated simultaneously. The optimal heat treatment schedule, microstructure and bending strength of the CAS glass ceramic were gained.
Application of MgO Concrete in China Dongfeng Arch Dam Foundation
Authors: Chen Chang Li , Tang Cheng Shu , Zhao Zhen Hua
Published: December 2010

In order to find out the long-term deformation behavior of MgO concrete,the nearly 10 years prototype observation data of Dongfeng arch dam foundation is analyzed. The results show that the MgO concrete has excellent delayed micro-expansion character, and its long-term expansive deformation always tends to stable level without any trend to contraction or infinite expansion, and by adding appropriate MgO expanding agent which was calcined at some high temperature into concrete, the cracking resistance of the concrete is improved. It is an effective way to construct dams excellently, efficiently and economically by using MgO concrete technology.
Energy-Absorption Property of Ceramic Fiber Reinforced Concrete
Authors: Su Hao Yang , Xu Jin Yu , Li Min , Li Ying
Published: December 2010

Full-automatic concrete pressure machine and 100-mm-diameter split Hopkinson pressure bar (SHPB) apparatus were used to investigate quasi-static and dynamic energy absorption property of ceramic fiber reinforced concrete (CRFRC) subjected to various high strain rates, which is compared to carbon fiber reinforced concrete at the same volume fraction of 0.1%, 0.2% and 0.3%. And the absorbing mechanism of CRFRC is analyzed. The results show that the quasi-static energy-absorption property of CRFRC increases with the volume of ceramic fiber and the relation presents linear approximations; the specific energy absorption of ceramic fiber reinforced concrete is strain rate-dependent dynamic strength-dependent under impact load, and the effect can be expressed by linear approximations. And the strain rate is more distinct when volume fraction of ceramic fiber increases. The energy absorption property of ceramic fiber reinforced concrete is superior to plain and carbon fiber reinforced concrete, especially at higher strain rate and volume.
Mechanics Performance of Complex High Titanium Heavy Slag Reinforcement Concrete Beam
Authors: Sun Jin Kun , Chen Wei , Huang Shuang Hua , Li Ying Min
Published: December 2010

Through the anti-bending performance of the normal section experiment on four complex high titanium heavy slag reinforcement concrete beams and two ordinary RC beams, we compare them with concrete strength and longitudinal reinforcement ratio as parameters, and explore the performance of complex high titanium heavy slag reinforcement concrete beams on supporting capacity, crack, stiffness and ductility. The results show that, under the same conditions designed, the performance of complex high titanium heavy slag reinforcement concrete beams on the cracking moment, ultimate moment, the average crack width, stiffness and ductility is better than that of ordinary RC beams, presenting a typical normal section destruction. The findings of the present study provides reference to the application of complex high titanium heavy slag concrete into engineer structuring.
The Assessment of Expansion Performance of Expansive Agent in Composite Cementitious Materials and its Mix Design
Authors: Miao Miao , Yan Pei Yu , Feng Jing Jing
Published: December 2010

The expansion performance of expansive agent in cement-HCSA-fly ash cementitious materials and its coordination with strength were studied by orthogonal test. Shrinkage-compensating mortars were prepared. The results show that the restrained expansion rate (RER) of mortars cured moistly, RER residue and expansion decline rate of mortars stored drily after 7d are well consistent with each other to assess the expansion performance of expansive agent. Increase of expansive agent content and decrease of fly ash content can lead to the growth of RER. The impacts of all the factors on RER of moistly-cured mortars are becoming steady when the age is longer than 7days. The 7-day RER of 6.35×10-4 is the critical value to judge whether the shrinkage of expansive mortar occurs after it moved from moisture into dry air at 7d. The expansive agent content has no need to exceed 10% in view of compensation efficiency unless slight improvement of expansion performance is desired. 35~50%, 20~50% and 20~35% of fly ash content are recommended respectively for water-binder ratio of 0.32 0.36 and 0.40 to obtain better coordination of expansion and strength.
A Study on Sliced Bamboo Veneer-Chinese Fir Glulam Composite Panel
Authors: Du Chun Gui
Published: December 2010

Previous studies have indicated that Chinese fir glulam has many defects on surface: color is singleness, knot is more, surface is roughness, etc. This paper presents a study on the manufacturing technology of sliced bamboo veneer-Chinese fir glulam composite panel. Sliced bamboo veneer were glued on both the top and bottom surface of Chinese fir glulam. The results showed: (1)sliced bamboo veneer can beautify the surface of Chinese fir glulam; (2)sliced bamboo veneer should directly overlay on the surface of Chinese fir glulam, and it is not suitable back lining non-woven fabric in gluing; (3)the optimal composite technological parameters are: unit pressure: 0.7MPa; hot pressing temperature: 100°C; hot pressing time: 4min.
Research on Mechanical Properties of Steel Fiber Reinforced High Performance Recycled Concrete
Authors: Li Wen Li , Chai Wen Ge , Yi Cheng , Gao Yan Li , Li Zhao Guang
Published: December 2010

In this paper, high-quality mineral admixtures and superplasticizer double mixing technology is used to produce high performance recycled concert (HPRC), and then steel fibers are used to modify the characteristics of HPRAC. The compressive strength, splitting tensile strength, ultimate bending load and fracture energy of HPRC with different content of steel fiber. Experiments suggest that with the increase of steel fiber content, the compressive strength doesn’t change too much, but the splitting tensile strength, ultimate bending load and facture energy increase dramatically. Therefore it can be concluded that increasing the content of steel fiber properly can improve the ductility and resistance to crack propagation of HPRC and enhance the ultimate load of HPRC bending member.
Effects of Mineral Admixtures on the Chloride Permeability of Hydraulic Concrete
Authors: Zhang Dong Qing , Li Xue Ying , Ma Xin Wei , Wang Zheng
Published: December 2010

The chloride permeability of concrete with slag or (20wt%, 30wt%, and 40wt% of binder) and binary slag and fly ash (the ratio of slag and fly ash 5:5, 4:6 and 6:4) was investigated in this study. The results show that the chloride permeability of concrete decreases firstly and increases latterly with the increasing of fly ash content. However, the permeability of concrete with slag decreases sharply with the slag content increases. Especially the content of slag is 40 wt%, the permeability is only 15.4% of the control concrete. The permeability of concrete using binary admixture of slag and fly ash is less than that of fly ash concrete and more than that of slag concrete.
Magnetic Stress Sensitivity Analysis for Ferromagnetic Material
Authors: Wang She Liang , Zhang Bo , Xiong Er Gang , Zhu Xi Yu
Published: December 2010

Based on counter magnetostriction effect the magnetization intensity and stress sensitivity was analyzed for ferromagnetic material. The stress sensitivity of magnetized material was discussed on basis of the law of minimum energy and movement of magnetic domain structure. In accordance with the effect of magnetization intensity from stress the applied stress can lead to movement of domain wall of magnetic domain in the demagnetizing state for ferromagnetic material when the net magnetic moment is equal to zero. Meanwhile easily magnetization axis can be established on known applied stress. Then when ferromagnetic material is forced by the applied stress the magnetization intensity can be changed obviously. It is happened so that magnetic flux is also changed simultaneously. The result shows that real-time strained condition of material can be judged on basis of testing change of magnetic flux. Furthermore the study theory of magnetic nondestructive testing of defect sensibility structure for long span steel structural is obtained through this analysis.
Curvature Ductility of Singly Reinforced CRC Beams (Part-II)
Authors: Yang Lin Hu , Zhu Han , Fafitis Apostolos
Published: December 2010

This article (Part-II) continues the work of a previous article (Part-I). It undertakes a theoretical analysis of the curvature ductility factor (CDF) of a singly reinforced CRC (crumb rubber concrete) beam and demonstrates how CRC’s material ductility is transformed into structural ductility of a reinforced CRC beam. The result shows that CDF for a reinforced CRC beam is much higher than that for a conventional concrete reinforced beam.
Coefficient of Linear Expansion of Air-Entraining Concrete with Silica Fume
Authors: Dou Jian Chao , Yang Jian Sen
Published: December 2010

The effect of water-cement ratio, air content, silica fume and sand ratio of concrete on the coefficient of linear expansion(CLE) was studied by orthogonal experiment. The results show that under a certain amount of cement material, CLE of concrete increase as the water-cement ratio increases and the effect of water-cement ratio on CLE of concrete is remarkable; with the increase of blending ratio of silica fume, the CLE of concrete increases; the CLE of concrete reduces with 3.5% air content in concrete, but rebound with 6% air content in concrete; with the sand rate increases, CLE of concrete increases; CLE per unit compressive strength of concrete with silica fume decreases with increase of silica fume content; CLE per unit compressive strength of concrete with air content increase when air content increase.
Preparation and Physicochemical Properties of Concrete Slump-Loss Resistance Agent for Small Slump
Authors: Duan Guo Rong , Huang Guo Hong , Wang Xin , Gong Ying
Published: December 2010

By the application of esterification-polymerization two-step synthesis method, comb-shaped polycarboxylate slump-loss resistance agent XBT for small slump concrete is prepared by controlling ester ratio. The experimental results of concrete and fresh cement paste indicate that XBT has excellent function of plasticity retention in small slump concrete. The experiment of gel permeation liquid chromatogram shows that XBT has wide range of molecular weight distribution, which may be the source of fine plasticity retention performance in the small slump concrete. The combined experiment between ultraviolet and conductivity indicates that there is strong adsorptive action between XBT and Ca2+, and their adsorptive characteristics may be closely related to the plasticity retention properties.
Separation of Crude Phenols from Bamboo Tar and Modification of Aminobenzenesulfonic-Based Superplasticizer
Authors: Jiang Xin Yuan , Zhao Jian Xin
Published: December 2010

Aminobenzenesulfonic-based superplasticizer is a kind of high range water reducer synthesized by sodium aminosulfonate, phenol and formaldehyde, as the expensive phenol and the bad workability of concrete added with it, so its application is limited. Bamboo tar is one of the byproducts from bamboo charcoal production, and for its complicated components it isn’t utilized effectively until now. Crude phenols extract was obtained from bamboo tar by using sodium hydroxide solution, and the synthesis of modified aminobenzenesulfonic-based superplasticizer by using crude phenols extract to substitute part of phenol was optimized, and the fluidity of cement paste, compressive strength and water-reducing rate of concrete added superplasticizers were also determined in this paper. The research results indicated that the fluidity of cement paste, concrete compressive strength during the same period, the water-reducing rate and the workability of concrete added with modified aminobenzenesulfonic-based superplasticizer synthesized by using crude phenols extract to substitute 10% phenol were better than that added with aminobenzenesulfonic -based superplasticizer synthesized by only phenol.
Size Dependent Micro-Stress-Field of Fibers in Eutectic Ceramic Rod
Authors: Lu Hai Xing , Liu Xie Quan , Ni Xin Hua , Sun Tao , Li Bao Feng
Published: December 2010

Considering the interaction between fiber-inclusion and strong constraining interphase, forth-phase model is suggested to determine the local stress field distribution of three-phase element in eutectic ceramic rod. On the basis of the volumetric average strain, the effective compliance tensor increment of eutectic ceramic rod is obtained. The remote stress boundary condition of the eutectic ceramic rod is accounted for getting the micro stress field of fibers in eutectic ceramic rod. The results show the micro stress field of the fiber-inclusion in eutectic ceramic rod is associated with the stiffness and the volume fractions of each component in eutectic ceramic rod, the shape of interphase and fiber. The micro stress field has apparent size effect: three direction stresses increase with the diameter of fiber- inclusion.
Design and Analysis for Hydraulic Travel System of Container Stacker
Authors: Han Hui Xian , Guo Xiong Hua , Cao Xian Li
Published: December 2010

Work conditions and requirements of a container stacker are analyzed. Aiming at the disadvantages of hydrodynamic travel system of stacker, a design method for hydraulic chassis of a stacker is presented. With a practical example, its operation performances under the work conditions of stable travel in low-speed are analyzed. New method to design its travel drive system is presented, it contains the hydraulic system design and component selection. It is considered that the manufacture cost for special hydraulic chassis of a stacker is equal to or lower than that of a hydrodynamics chassis, so there is wide application prospect of it.
Crosslinking and Reinforcement of PET/TiO2/Clay Composites for Pavement Applications
Authors: Lopez Rodriguez Angelica Silvestre , Sifuentes-Gallardo Pio , Sorto Castañon Carolina , Díaz Flores Laura Lorena , Hernández Rivera Miguel Angel , Falconi Calderon Richart
Published: December 2010

This project studies the alternative chemical recycling of disposable bottles as raw material for the manufacture of a product known as polymeric concrete, which has several applications in the construction industry. Crosslinked materials from polyethylene terephthalate (PET), glycerol and clay were obtained. First recycled PET bottles were washed, cut and dried; after bis-hydroxyethyl terephthalate monomer was obtained from depolimerization reaction of PET. The monomer, glycerol and titanium dioxide reacts to synthesize a polymeric concrete. Materials with concentrations of clay from 1, 10, 20, 30, 40 and 50%w/w were obtained. Differential scanning calorimeter (DSC), Soxhlet extraction, colorimetry and Shore D hardness were used to characterize the materials. The results indicated a degree of crosslinking in the synthesized material when the amount of clay was increased. A melting point around 265 °C was not observed by DSC analysis; this suggests that a crosslinked material was formed. By TGA analysis temperature degradation was observed at 394°C, which it was increasing from 408 to 416°C according to the addition of clay content. A bad dispersion of particles in the crosslinked polymer decreased the thermal stability of PET when the clay content was increased.
Development in Research of Engineering Investigation for Offshore Wind Farm
Authors: Huang Tian Rong , Wu Peng Cheng , Cheng Gong Qi , Yue Peng Jun
Published: December 2010

The engineering investigation was researched for offshore wind farm. On several occasions the soil conditions had proven to be a key area for offshore wind farm. The offshore engineering investigations, usually based on survey, test, simulation and analysis methods, were established information about seabed topography, seafloor soil, and offshore environment. The principle and procedures of engineering investigation were studied, offshore site conditions were analyzed for meteorological conditions, oceanographic conditions, soil conditions, seismic activity, biology, and various human activities, and engineering investigations were researched to various foundation types, and time schedule for offshore engineering investigations was established. Experience of engineering investigations was put forward to combine with foreign offshore wind farm. The engineering investigations provide project basis of various structure on offshore wind farm.
Study on Selection and Optimization of Vertical Transportation Equipment for High-Rise Construction
Authors: Qi Xi Jing , Zhou Xiao Hu , Song Ming Liang , Li Feng Ming
Published: December 2010

High-rise buildings in China has developed rapidly in recent years and problems such as construction and vertical transportation have been paid close attention more and more by society. The safety project management objective system mentioned in this article has comprehensively considered the characteristics of high-rise construction and vertical transportation and provided a comprehensive evaluation system for vertical transportation equipment for high-rise construction, which may be used for guiding equipment selection and optimization of equipment use. Meanwhile, the study results are applied in practical project to verify its effectiveness and practicability, so as to guide the enterprises to reasonably select and use vertical transportation equipment for high-rise construction and to realize the integration benefits of the project.
Multidisciplinary Teaching - Changing Collaboration during Building Design
Authors: Dederichs Anne , Karlshøj Jan
Published: December 2010

Traditionally the design phase was carried out by one single person – the master builder. Industrialization and technical development led to a split of the role of the design master into two: the architect and the engineer. Today, demands on functionality such as energy and cost efficiency led to an increasing need of functioning collaboration in large teams during the design phase; as well as a need of new work methods within the process. This calls for employees who are experienced in collaborating in interdisciplinary teams. To fulfill this demand a multidisciplinary course in “Advanced building design” has been developed at the Technical University of Denmark. The goal of the course is to provide training in teamwork at the final stage of the engineering education. The course has been carried out twice. It was held by a multidisciplinary team of professors in periods 2008/09 and 2009/10. The team of professors and the student teams had similar working conditions. These teams were subject of a questionnaire investigation on collaboration and team work. The study has the following findings. Collaboration can be learned and improves in time. It is shown that the team leader is not necessarily to be found within on specific profession. The team-structure was generally flat and decisions were mostly made in consensus. It is worthwhile to offer a multidisciplinary course and give engineering students experience in collaboration methods.
A New Method of Gradation Design about Rutting Resistance of Asphalt Pavement
Authors: Zhu Bao Lin , Huang Xin , Jing Yan Ping
Published: December 2010

The article derived the formula of continuous particle size of asphalt aggregate packing density based on the Stovall model; according to the relationship between porosity and rutting, rutting prediction model was established; by experiment to determine the parameters in the formula to be determined , and the applicability of the formula was verified, the results showed that: the formula can calculate air voids and dynamic stability of asphalt mixture by aggregate size distribution and the aggregate ratio .
Technology of Preventing the Metro Tunnel Disaster Caused by Overhead Excavation in Underground Space
Authors: Liu Chen , Zhang Ji Chao , Wang Ke Yi
Published: December 2010

Rapid urbanization process brings large-scale excavation engineering and subway tunnel in city. Especially ,some excavations are just above the subway tunnel with almost no distance between the excavations and the subway. How to effectively reduce the deformation of tunnel becomes a subject worthy of researching. Based on the underground space in Zhujiang New Town which would be constructed cross metro tunnel, protecting technology has been proposed to guarantee the metro tunnel’s safety by application of time and space effect, which could benefit the following similar projects.
Microstructure, Hardness and Oxidation Resistance of CrN and CrAlN Coatings Synthesized by Multi-Arc Ion Plating Technology
Authors: Cai Zhi Hai , Ping Zhang , Di Yue Lan
Published: December 2010

Approximately 2 μm thick CrN and CrAlN coatings were synthesized on silicon and spring steel substrate by multi-arc ion plating technology. The nanoindentation techniques, Auger electron spectroscopy (AES) analysis, scanning electron microscopy, X-ray diffraction and oxidation furnace were used to investigate the mechanical property, oxidation resistance and microstructure of the coatings. The XRD data showed that the CrN and CrAlN coatings exhibited B1 NaCl structure. Nanoindentation measurements showed that as-deposited CrN and CrAlN coatings exhibited a hardness of 19 and 30 GPa respectively. Compared with CrN coatings, the CrAlN composite coatings show much better oxidation resistance. And the oxidation resistance ability will enhance with increasing Al content, because A12O3 will form after oxidation in high temperature condition which could reduce the diffusivity ability of oxygen.
Analysis on ROI Characteristics in CT Images of Q2 Loess under Freezing Temperature
Authors: Ye Wan Jun , Yang Geng She , Niu Fu Jun , Zhuang Ning , Zheng Xuan Rong
Published: December 2010

Freeze-thaw action is one of causes to loess disaster. Loess structure and mechanical properties are quite different due to its structural model, unsaturation and salt content, which make loess freezing much complex. The samples from the site are set with different moisture content and lowered their temperature to 0°C, -10°C and -20°C respectively, and then the microscopic damage propagation and damage structural variation in the internal loess have been studied under the different freezing temperatures through CT scanning experimental technique. With zoning methods and zoning statistic frequency, the process of damage evolution has been analyzed, which provides specific guideline for researches on geotechnical engineering in loess region.
The Characters of KI and KII in Notched Beam
Authors: Xu Feng Guang , Gao Qian , Liu Zeng Hui
Published: December 2010

The distributions of stress intensity factor KI and KII in notched beam specimens have been obtained in this paper by researching on internal force distributions, photoelastic experiments and statistics from numerical results. Two approximate formulae of KI and KII have been constructed. A simple and correct way to calculate KI and KII of beam is provided.
Experimental Study of Mechanical Properties of Rock Mass Containing Intermittent Joints of Prefabricated
Authors: Wang Rui Hong , Li Jian Lin , Guo Jing , Jiang Yu Zhou , Dang Li
Published: December 2010

Most of the engineering rock masses contain a variety of different levels of geological tectonic joints and weak planes, which can weaken the rock strength. The rock masses containing joints have completely different mechanical properties with the intact ones. Through loading failure tests on the rock masses containing two intermittent joints of prefabricated of different spacing, the differences between jointed rock mass and intact one were studied. The research shows that: 1. Comparing with the intact rock mass, the stress-strain curve of jointed one has a relatively large fluctuation near the peak, it isn’t smooth, and there's a reduction in the stage of plastic flow after yielding; ultimate strength decreases obviously, joint depth has a great impact on strength, and there's no necessary link between ultimate strength of rock mass and joints spacing. 2. When the loading is failure, the elastic and deformation modulus of rock mass decrease obviously comparing with those of the intact rock mass, which tend small generally with the increment of joints spacing, however, they have a relatively complex relation and it isn't linear. 3. The failure characteristics of jointed rock mass are different from those of the intact rock mass, failure planes are relatively complex and no longer single shear or complementary shear ones, which presents that shear failures occur along the end of prefabricated joints with few extensional cracks; the spacing of prefabricated joints have a great impact on the failure pattern of rock mass. The research results can provide certain references for the mechanical parameters selection of jointed rock mass of engineering design and numerical analysis.
Reduced-Scale Model Tests of Fires in Railway Tunnel and Structure Fire Safety
Authors: Zhao Hong Li , Xu Zhi Sheng , Jiang Xue Peng
Published: December 2010

The high-temperature toxic gas released by long railway tunnel fires not only causes great harm to persons, but also damages the structure of the tunnel which will reduce the overall stability of tunnel. In order to diminish the damage to tunnel structure produced by a tunnel fire, on the basis of the first extra-long underwater railway tunnel in China, some reduced-scale tests were carried out to study the distribution of smoke temperature along the tunnel ceiling, the smoke velocity and the backlayering distance with the fire size of 63KW. The longitudinal ventilation velocity and the tunnel gradient varied in these tests. The smoke temperature below the tunnel ceiling in different times and under different longitudinal ventilation velocity, the smoke velocity under the ceiling, and the backlayering distance in the presence of different ventilation velocity are acquired from the tests. The conclusions have the guiding meaning to the disaster prevention design and construction of structure fire safety in tunnel fires, and all the experimental data presented in this paper are applicable for the verification of numerical models.
Reliability Analysis of Stability of Foundation Pit Supported by Composite Soil Nailing
Authors: Zhao Yan Lin , An Wei Guang
Published: December 2010

Based on the limit equilibrium theory and the circular slip surface method, the state equation of limit equilibrium and the calculation model of the most dangerous sliding surface for inner global stability of foundation pit supported by the prestressed anchor composite soil nailing is established with the disturbing force method. And the searching and solving method of the most dangerous sliding surface is optimized with the SLP optimization method and the simplex optimization method. Then with the mechanical parameters of soil as random variables, the reliability index of inner global stability of foundation pit is calculated with the design checking point method. Finally, a practical project is used to analyze the sensitivity of the reliability index to the coefficients of variability of all random variables.
Two-Scale Analysis for the Mechanical Properties of Nano-Composites with Non-Linear Interface
Authors: Luo Dong Mei , Zhou Ying Long , Yang Hong , Li Li Fen
Published: December 2010

Combining the cohesive zone elements into the two-scale homogenization method, the effective mechanical properties of nano-composites with a non-linear interface are analyzed. A periodic microscopic representative volume element (RVE) is modeled using a four-phase composite composed of matrix, nano-tube, bonded, and debonded interfaces. The debonded interface is simultaneously considered as bilinear plastic material satisfying the von Mises conditions in the presented algorithm, and a simple elastic–plastic constitutive model is established to study the non-linear effective elastic properties of nano-composites and equivalent stress for interface and nano-tube. The predicted results show a strong non-linear dependence of the effective mechanical properties on the interfacial modulus and yield stress.
Stability Analysis of Tunnel Structure in Gob Area
Authors: Zhuang Ning , Ye Wan Jun , Zhu Ku Zhu
Published: December 2010

In this paper a 3D FEM model is established to simulate the dayuliang tunnel which is located in the gob area. The vertical and horizontal surface displacements of gob area are obtained in different simulation condition. By these calculated results the character and key region of gob surface subsidence is analyzed. The warning line of subsidence basin is determined. In order to control tunnel structural’s stability its deformation and stress character are also researched to determine stress concentration and important supporting position. These analysis results provide a scientific basis and technical guidance for the tunnel construction in gob area.
Initial Crack Propagation Directions of Branched Crack under Tension with Finite Element Analysis
Authors: Zhu Yong , Su Ray K.L. , Yu Qi Cai
Published: December 2010

The initial crack propagation directions of branched cracks under tension are investigated. In this study, the material is assumed to be brittle and deformed linear elastically. The elastic stress fields and stress intensity factors are obtained by using finite element analysis method. Various parameters which including the lengths, the directions and the locations of branched cracks are investigated to study their effects on the crack initiation angles. Three kinds of crack propagation criteria are employed to obtain the crack initiation angles. The effects of crack propagation directions due to the use of different crack initiation criteria are studied and discussed in details.
Study of the Influence of Capillary Water Surface Tension on Drying Shrinkage and Self-Shrinkage Deformation of Concrete
Authors: Zhang Yong Cun , Li Qing Ning
Published: December 2010

By analyzing and simplifying the force status about the concave water surface and wall of concrete capillary pores,the model for force calculation of capillary walls is established.When the concave water surface is going down,capillary walls will contract. Concrete volume shrinkage strain at different surface tension is approximately calculated out by using finite element software ANSYS,from which the relationship between the surface tension of capillary water and drying shrinkage,early self-shrinkage of concrete is obtained.
Study on High Cutting Slopes with Horizontal Soft-Hard Strata in Three Gorges Reservoir Area
Authors: Yang Guo Xiang , Dong Jin Yu , Wu Fa Quan , Wang Dong , Yang Ji Hong
Published: December 2010

High cutting slopes with nearly horizontal soft-hard alternant strata are widely distributed in three gorges reservoir area, the soft and hard rocks are mainly mud stone and sandstone of Jurassic system. Sliding failure of this kind of slope is also the main geo-hazards in this area. Firstly, this paper analyzed the impact of topography, water as well as the differential weathering and combination characteristics of soft and hard rocks etc. on the sliding failure of slopes; secondly, sliding failure modes of this kind of slope were classified into four types including circular sliding, sliding along the extroversion structural surface, sliding along the mudded intercalation and wedge sliding, they were analyzed combined with case study. And lastly, support methods against the certain failure mode were put forward. The research results are significant to the support and treatment of high cutting slopes in Three gorges area.
Discuss on Highly Weathered Metamorphic Fillers as Soft Stone Fillers
Authors: Yang Ling Yun , Xue Feng , Huang Jun , Hou Chao Qun
Published: December 2010

In order to discuss on highly weathered metamorphic fillers as soft stone fillers，firstly the CBR tests for analysis on viability as embankment filler are conducted on three different highly weathered metamorphic fillers. Secondly the rock strength tests and particle broken tests are processed to study on how weathered degree and rock structure have an effect on them. Based on the above conclusions, evaluation criteria are proposed that have certain guidance and reference on mountainous highway construction.
Research of Application on Corrugated Pipe Heat Exchanger to Recycling Sewage Heat
Authors: Shi Yan , Bai Li
Published: December 2010

Basing on the particular characteristics of corrugated pipe heat exchanger, the calculation method of the submersible corrugated pipe sewage heat exchanger is put forward and set up the computational procedure. By using the urban sewage heat exchanger recovery system, the accuracy of design procedure is to be test. The test results show that the sewage heat exchanger designed by this way can satisfy the heat load for building. The optimization design and engineering application can be provided technical parameters of this research.
Elaborate Simulation Method for the Influence of Soil Excavation of Shield Tunnels on Existing Pile Foundations
Authors: Zhang Rong Jun , Zheng Jun Jie , Dong You Kou
Published: December 2010

Existing numerical simulation methods tend to neglect some details of shield tunnelling and the cyclic shear characteristics of pile-soil interface. In this paper, an elaborate simulation method is firstly proposed to simulate the advancing of shield machines according to the details of shield tunnelling. Then an improved constitutive model for pile-soil interface, which can factually consider the cyclic shear characteristics, is also developed. Finally, through a case study, it can be found that the proposed simulation method can provide reliable estimation for this problem, and it is important to factually consider the cyclic shear characteristics of pile-soil interface.
The Research on the Recognition Technique of Rock AE and Noise Signal
Authors: He Jian Ping , Wang Ning
Published: December 2010

AE signal waveform Envelope is damped oscillation process, its maximum amplitude descending edge Envelope is exponential rule decay oscillation process ，others noises higher than oscillation delay. The thesis analysis rock AE and noise signal in the mine，on the basis of Fourier transform spectral analysis to found the noise spectrum characteristics, setting up noise database, according to the site data acquisition rock AE and environmental noise signal, with its characters spectral data to wavelet multi-scale decomposed，supplemented by Fourier transform spectral analysis, basing on noise spectral characters, some scale of wavelet decomposition is mulled, the signal of wave coefficient of the approximation elements reconstructed， eliminating disturbance and noise, showing real rock sounds. Results demonstrate that the recognition technique can advance effective data reliability and data analysis precision, making reality significant for monitoring and prediction on rock crack regular and development orientation.
Experimental Study on Fundamental Mechanical Properties of Autoclaved Sand-lime Brick Masonr
Authors: Zhang Zhong Ji
Published: December 2010

Experimental data are obtained by a series of fundamental mechanical properties experiments on autoclaved sand-lime brick masonry such as compressive strength experiment， shear strength experiment, bending tensile strength experiment, they provide the experiment evidence for writing Hunan province engineering construction local standard named "Technical specification for autoclaved sand-lime brick masonry building ". And following conclusions are drawn through analyzing experiment data and experiment phenomenon: With mortar intensity increasing ,the masonry 's cracking load and ultimate load are approaching in the compression strength experiment; Except that the experiment average value in the bending tensile experiment of masonry along with joint section is lower than the calculated value of standardized formula obviously ,the other are bigger than that of standardized formula; There is a feature of optimal combination of strength for mortar and block; The author derived the formula of bending tensile strength of autoclaved sand-lime brick masonry.
High Temperature Mechanical Behaviors of Concrete
Authors: Xu Yuan , Wang Ru Heng , Yao Hua Chuan , Jia Bin
Published: December 2010

Using microwave heating method to establish a set of effective technology about uniaxial compression test of concrete, and obtain the experiment phenomenon of concrete when the temperature is 16 -650 . Experiment results indicate that when concrete is damaged by high temperature, the strength of concrete decreases, the peak strain increases, and the elastic modulus decreases. Based on test data, a unified equation was putted forward to describe the relation between concrete compressive strength, the peak strain, elastic modulus and temperature. While, obtain concrete temperature stress and strain curve, and analysis shows that it gradually becomes compressed with the increase of temperature, peak point falls and moves right obviously.
Study On Damage Characteristics Of Concrete Under Impact Load
Authors: Jia Bin , Yao Hua Chuan , Bai Le , Tao Jun Lin
Published: December 2010

This article established strain characterization of damage factor equation of concrete in elastic stage, and completed the concrete specimens dynamic damage ‘freezing in’ test. A series of concrete under the strain rate had been gotten, and the damage characteristics of concrete under impact load was analysed. The damage evolution process of concrete material was related to both strain size and strain rate size, and the damage evolution and development and strain rate showedf a power function relation. Then the damage evolution equation used to describe concrete materials could be fitted.
Orthogonal Experimental Study on Properties of Hybrid Fiber Reinforced Cement Mortar
Authors: Yuan Hai Yan , Zhang Shui , Li Guo Zhong
Published: December 2010

By adopting the method of orthogonal experimental design, the effect of three independent variables, that is steel fiber fraction, polypropylene fiber fraction and silica fume fraction on the compressive strength, flexural strength and shrinkage of cement mortar was studied. The results indicate that steel fiber is one of the most important factors affecting compressive strength and shrinkage, and polypropylene fiber is one of the most important factors affecting flexural strength and shrinkage of cement mortar. By using deviation analysis to analyze the orthogonal experiment results, the optimized mix proportion of hybrid fiber reinforced cement mortar is determined. The hybrid effect of steel fiber and polypropylene fiber on the properties of cement mortar is discussed.
Influence of Strontium Doping on Sintering and Performance of Alite-Rich Cement Clinker
Authors: Li Gui Qiang , Wang Shou De , Yin Chao Nan , Lu Ling Chao
Published: December 2010

The synthesis conditions and mechanical performance of alite-rich cement clinker were investigated by the orthogonal test method. Sintering temperature, sintering time and contents of strontium oxide or strontium sulfate were taken as the influencing factors for the orthogonal test. The experimental results show that the optimal sintering temperature and sintering time are 1450 °C and 60 min, and the best strontium oxide or strontium sulfate content in the clinker is 1.5% and 0.5%, respectively. The doping of strontium oxide or strontium sulfate can promote the formation of alite mineral. That is beneficial to the increase of cement strength. The early strength of cement can be improved by addition of strontium oxide, and the long strength of cement can be increased through adding a little of strontium sulfate.
Fatigue Test of Asphalt Mixture and Ultrasonic Forecast
Authors: Wu Jin Rong
Published: December 2010

The fatigue behavior of the asphalt mixtures beams is experimented by sine wave load, and the fatigue life is predicted by ultrasonic ware theories. Test results show that ultrasonic ware can reflect better fatigue process, and it is an effective method to analyze and forecast fatigue property.
Experimental Testing of Fiber Reinforced Polymer-Concrete Composite Beam
Authors: Wang Yan Lei , Hao Qing Duo , Ou Jin Ping
Published: December 2010

A new form of fiber reinforced polymer (FRP)-concrete composite beam is proposed in this study. The proposed composite beam consists of a GFRP box beam combined with a thin layer of concrete in the compression zone. The interaction between the GFRP beam and the concrete was obtained by bonding coarse-sand on the top flange of the GFRP beam. One GFRP box beam and one GFRP-concrete composite beam were investigated in four-point bending test. Load-deflection response, mid-span longitudinal strain distributions and interface slip between GFRP beam and the concrete for the proposed composite beam were studied. Following conclusions are drawn from this study: (1) the stiffness and strength of the composite beam has been significantly increased, and the cost-to-stiffness ratio of the composite beam has been drastically reduced comparing with GFRP-only box beam; (2) a good composite action has been achieved between the GFRP beam and the concrete; (3) crushing of concrete in compression defines flexural collapse of the proposed composite beam..
Experimental Research and Finite Element Analysis on Behavior of Steel Frame with Semi-Rigid Connections
Authors: Li Feng Xia , Xin Bu
Published: December 2010

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.
Prediction of Saturate Concrete Elastic Modulus by Considering Pores and Microcracks
Authors: Zheng Dan , Li Xin Xin
Published: December 2010

The elastic modulus of saturate concrete is investigated in this paper. Based on micromechanics of composite materials, the elastic modulus of saturate concrete is obtained by considering the deformation of both pore and microcracks in concrete. It is assumed that concrete deformation includes the contribution of concrete matrix, pore water and microcracks. The water viscosity between microcracks and the further hydration of cement are both taken into account too in this paper. The comparison between the results by the model proposed in this paper and by existed experiments indicates a favorable agreement.
Microstructure Modeling of the Ribbed Steel Bar Hot Rolling of V-Microalloyed Steel
Authors: Yang Lei , He Yi Zhu , Yuan Xiao Min
Published: December 2010

This paper proposes an integrated model for the prediction of the pass-by-pass evolution of the austenite grain size of the ribbed steel bar hot rolling. The integrated model consists of a strain model, a temperature model, a microstructure evolution model of austenite grain size and a flow stress model. Hot rod rolling experiments are conducted to examine the proposed analytical models. The integrated model is employed to examine the effects of modifications of the refined austenite grain size of the 500MPa ribbed steel bar. Refinement of ferrite could be realized by refining the austenite grain size at the final pass.