bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation Study of Fracture Process of Concrete Mesoscopic Structure by Manifold Method
Authors: Zhao Yan , Zhang Guo Xin , Wu Xiao Chuan , Chai Fu Xin
Published: May 2011

On the assumption that the concrete is a multi-phases composite material composed of matrix, aggregate and the bonding interface, the failure progress of concrete is simulated. It requires that numerical method not only can simulate forces and stresses, the failure growth and contacts, but also can simulate the discontinuities such as joints and cracks，the large deformation after the failure and the propagation of multi-cracks. By adding the function of tracing the propagation of cracks，the Numerical Manifold Method proposed by Shi Genhua is developed which can simulate both the discontinuity of block system and the tensile or shear failure of intact block. The random aggregate model according to the Monte Carlo method and Fuller Graded Formula is carried out, and the concrete fracture process is simulated by the NMM. The strength and failure pattern are in good agreement with the experimental data, which shows that the method put forward and the program developed in this paper can effectively simulate the fracture process of concrete composed of multi-cracks.
Inverse Heat Conduction Problem of the Temperature Field with Artificial Ground Freezing Method
Authors: Xu Shi Liang
Published: May 2011

The Artificial Ground Freezing (AGF) Method play an important role in the geotechnical engineering and the back analysis of thermal conductivity of frozen soil is the main inverse heat conduction problem of temperature field. In this paper the physical modelling test of AGF is carried out with double-row-pipe freezing in the lab. According to the measured temperature, the back analysis of thermal conductivity of frozen soil is solved based on the two-dimensional finite element simulation and the least square principle. It is helpful to investigate the freezing process and determine the frozen wall thickness.
Cyclic Simple Shear Tests on Base Isolation Using Soilbags
Authors: Liu Si Hong , Wang Yan Qiao , Gao Jiao Rong , Jin Yuan Zheng
Published: May 2011

Soilbags have been understood to have the effect of vibration reduction and can be used as a kind of base isolation in building foundations. In this paper, a series of cyclic simple shear tests were carried out on soilbags filled with three kinds of soils under different vertical stresses to investigate the damping and stiffness characters of the soilbags. The results show that soilbags have a relatively high damping ratio and variable horizontal stiffness so that they can be used as base isolation materials.
Column Effective Length Factor and Girder Parametric Analysis for the Components of Xinqiao International Airport Terminal
Authors: Li De Zhang , Ding Da Yi , Wang Yuan Qing , Liu Li Yuan , Wan Hai Ying
Published: May 2011

The steel structure of Hefei Xinqiao International Airport Terminal was taken as a background of this article. The large-span frame is a typical frame of the structure. The curved box-girders are the critical parts of the whole frame. This paper focused on the mechanical properties of the curved girders, as well as the influence on box-columns connected with them. Stability problem is a key problem in the steel structure design, and effective length factor is a way to reflect the stability problem in code for design. In this paper, the whole model of the airport terminal was established to conduct eigenvalue buckling analysis to obtain effective length factors of the box-columns connected to the curved box-girder. In the finite model, a unified axial force was applied on the end of the box-column, and the elements of the box-columns and the adjacent members were refined. Then the effective length factors were derived through the buckling models. In this paper, the curved box-girders of Hefei airport building were studied using finite element software ANSYS. The local model of the curved box-girders were set up to study the mechanical properties of the curved girders including the ultimate capacity analysis. Parametric analysis of the girders was carried out, and the results could be used to guide the design. The results show that finite element method is a convenient way of calculating effective length factors for members with complex boundary conditions, and analysis of local models provides reasonable suggestions for design.
Test and Finite Element Analysis on Dynamic Characteristic about Ultra-Long Bored Pile
Authors: Chen Shun Wei , Han Wen Ying , Xu Dong Qiang
Published: May 2011

The present standards for designing of ultra-long pile exist the contradiction between theory and practice; By combining the projects and finite element calculation and analyzing the characteristics of force and deformation, we can get the conclusion that there is asynchronous nature between the side resistance and the tip resistance in different soil layers. Meanwhile, the pile tip resistance has not been fully realized. To solve the above problems, I put forward reasonable proposals in order to make up for the deficiencies in designing. Introduction
Advances in Application and Research of Suspendome Structures
Authors: Shi Kai Rong , Zhang Yi Liang , Wang Long
Published: May 2011

The suspendome structure is a new-type of hybrid prestressed spatial structural system which has been developing on the basis of single-layer latticed shell structure and cable dome structure. The wide application prospects of this type of structure have been presented initially since its emergence around ten years ago. Several representative engineering applications of suspendome structures are introduced, and the research status of this structure at home and abroad is summarized. Moreover, further research orientations of suspendome structures are discussed and prospected.
Research on Construction of Rammed Earth Buildings
Authors: Zhao De Jun , Zhang Yin , Lu Jun Long
Published: May 2011

As for the form of a earth buildings ,rammed earth buildings have the advantages of green and environmental protection, easy and fast construction, low cost. This paper analyzes the raw material requirements ,structural types , construction technology and inspection of rammed earth buildings, focusing on the discussion of the quality inspection methods to provide a reference for the construction of rural residential adobe buildings.
The Launching Technique for Shield-Driven Tunnel with an Under-Pressure Soil-Chamber in Soft Layers
Authors: Yan Bo , Yang Guo Long , Lin Hui , Shi Chang Xue
Published: May 2011

In order to improving the launching technique in soft layer, the paper proposed the soil-chamber under pressure on the launching technique basing on engineering practices. The main principle is: using the earth pressure equilibrium, grouting the filling material when the Shield launching, establishing the active earth pressure ahead of time, which makes in advance the action pressure supports to the coarse sand cross section, that prevents from the water and soil spouting effectively. Because the active earth pressure, enhance the initial sending safety coefficient, and shorten the reinforcement length of the initial launching, and decrease the initial launching cost.
Development of Natural Organic Matter as a Permeable Reactive Barrier Medium for Pipeline Leakage
Authors: Wang Ya Jun , Wang Jin Xi
Published: May 2011

This paper presents the development of a new remediation technology of contaminated soil and groundwater using humic acid (HA) in permeable reactive barrier (PRB) for pipeline leakage. The objective of this study was to use humic acid that could be medium within a PRB to filter complex contaminated soil and groundwater containing chromium. Leakage of pollutants (such as hydrocarbon、gasoline、oil、wastewater、heavy metal et al) has a large economic and environmental impact. When a pipeline leak is large or undiscovered for a longer period of time, substantial volumes of gases and liquids can leak into the soil and groundwater, which can develop into dangerous situations involving costly remediation works. Traditional methods for remedying contaminated soil and groundwater from pipeline leakage, such as drilling and geochemical analysis, are destructive, time consuming and expensive. A PRB was determined to be the best option for remedying groundwater that has become contaminated with a wide range of organic contaminants (i.e., benzene, toluene, methylbenzene, xylene and polyaromatic hydrocarbons), heavy metals (i.e., lead and arsenic). PRB is installed in or down gradient from the flow path of a contaminant plume. The contaminants in the plume react with the media inside the barrier to either break the compound down into harmless products or immobilize contaminants by precipitation or sorption. It is made up of humic acid that reduce contaminants. With the development of industry and agriculture, environmental contamination has become more and more serious, especially heavy metal pollution, have been a major environmental issue, drawing much scientific and public attention. Chromium is identified as “priority pollutant” by the United States Environment Protection Agency (US EPA). the measurements show a significant increase of the adsorption of Cr (VI) because of the complexion reaction between HA and Cr (VI) occurred under acidic condition. It could be concluded that HA could be used effectively on remediation of Cr (VI)-contaminated soil and groundwater in a wide range of pH, with or without sunlight.
Research on Defect and Adjustment of Complex Shear Wall Partitioned Design Method
Authors: Fu Xue Yi , Qu Jia Xin
Published: May 2011

Both reference [1~2] method and partitioned design method (GB 50010-2002) were adopted to design complex shear walls, and some factors such as axial compression ratio, reinforcing ratio, section dimension, concrete strength grade and effective flange width were considered, then their limited loading capacity would be compared with each other when axial force was considered as a fixed value. It was found that there were some defects of complex shear wall partitioned design method. And its applied conditions were suggested, which included section restricted condition and limited value of axial compression ratio. When these conditions couldn’t be satisfied, the adjusted reinforcement partitioned design method of reference [3] was suggested. If the uneconomical problem of partitioned design method could not be accepted, whole section design method of reference [1~2] would be suggested.
Preliminary Research on Waste Incineration Bottom Ash Concrete
Authors: Zhang Rui , Zhang Tao
Published: May 2011

We use the bottom ash from Harbin Municipal Solid Waste Incineration Plant as concrete coarse aggregate and study the engineering properties of the coarse aggregate, failure mode of waste incineration bottom ash concrete, the relationship between compressive strength and bottom ash coarse aggregate replacement rate, water cement ratio, apparent density and development trend of compressive strength. Comparing with natural aggregates, the bottom ash has higher water absorption rate, lower apparent density and crushing value index. The failure mode of waste incineration bottom ash concrete is similar to ordinary concrete and the flat and elongated particles have effect on compressive strength. Bottom ash coarse aggregate replacement rate has different effects on compressive strength in different water cement ratio. Compressive strength of waste incineration bottom ash concrete has the same development trend with ordinary concrete. Compressive strength and apparent density has a linear relation.
Preparation of Cement Water-Reducer by Sulfonation Modifying of Wheat Straw Hydroxymethyl Ethanol Lignin
Authors: Li Jin Bao , Zhang Mei Yun , Xiu Hui Juan , Cao Jian Wu
Published: May 2011

Modified lignin cement water-reducer was prepared via hydroxymethylation followed sulfonation of wheat straw ethanol lignin. The optimum process conditions of sulfonation of wheat straw ethanol lignin were mainly investigated. Fourier transform infrared spectroscopy (FT-IR) was performed to characterize the chemical structure of mofified ethanol lignin. Its morphology was revealed by the scanning electron microscopy (SEM) observation. The application results showed that when the modified lignin dosage was 0.5% the fluidity of cement paste reached 208mm, water-reducing ratio was 14.9% which was 30.7% higher than using commercial Sodium Lignosulfonate; and with the addition of modified ethanol lignin, the 3 and 7 d compressive strengths of concrete are13.8 % and 9.9 % higher than using commercial Sodium Lignosulfonate respectively.
Influence of Fly Ash as Cement Replacement on Chloride Penetration and Frost Resistance of Recycled Concrete
Authors: Wu Xiang Hao , Yuan Pan , Jiao Yan Tao
Published: May 2011

The influence of fly ash as cement replacement on pore structure, chloride penetration and frost resistance of recycled concrete is investigated by evaporable water test, chloride natural diffusion test, and freeze-thawing test. The experimental results indicate that adding fly ash to recycled concrete can decrease its porosity and improve its pore size distribution. Chloride penetration resistance of recycled concrete is enhanced firstly and then reduced with increasing of fly ash content. The best proportion replacing cement with fly ash is 20%. Fly ash content has a certain influence on the frost resistance of recycled concrete, and the frost resistance of recycled concrete only has been improved when the proportion of fly ash replacing cement achieves more than 20%.
The Relationship between the Strength and the Pore Structures of Cement Paste with Mineral Admixtures
Authors: Li Yue , Bao Jun Ling , Sui Chun E , Du Xiu Li
Published: May 2011

This paper presents the effects of mineral admixtures and the water to binder ratio (W/B) on the tensile and compressive strength and micro pore structure of hardened cement pastes. The test results show that: with the water to binder ratio increasing, the tensile and compressive strength of cement paste with different mineral admixtures will decrease, air content and mean pore diameter will decrease and the cement paste with the ground blast furnace slag is the lowest. The artificial neural network based on its nonlinear mapping function can fit the relationship between strength and pore structure more accurate than an empirical formula.
Modeling Alkali-Silica Reaction Using Image Analysis and Finite Element Analysis
Authors: Shin Jun Ho , Jee Nam Yong , Struble Leslie J. , Kirkpatrick R. James
Published: May 2011

The objective of this study is to develop a numerical model based on microstructural images of concrete and fundamental material properties of each constituent of concrete subjected to alkali-silica reaction (ASR). A microstructure-based finite element approach is employed directly to analyze the mechanical response of concrete to ASR. The modeling work involves acquiring and processing of microstructural images of specimens suffering from ASR using scanning electron microscopy, and implementing finite element program to analyze the microstructural images. The formulation of this model is based on pressure caused by the ASR product and on properties such as Young’s modulus and Poisson’s ratio. The finite element analysis program used to simulate structural behavior of structures attacked by ASR is object-oriented finite element developed at National Institute of Standards and Technology. The numerical results from this model are compared with experimental data, which have been measured using ASTM standard test C1260. The results show that the development and widening of cracks by formation and swelling of ASR gel cause the majority of expansion of mortar specimens rather than elastic elongation due to gel swelling.
Effect of Desulfurization Ash with Different Calcium Sulfite Content on Performance of Cement Based Materials
Authors: Wen Xiao Dong , Xie Dong Dong , Yi Yong , Xu Zhang Jie
Published: May 2011

According to the desulphurization reaction temperature and the content of calcium sulfite, FGD ash is simulated, that is the ordinary fly ash mixed with different weight percentage of CaSO3·1/2H2O is followed by drying at 100°C. And then by the experiment of workability, strength, sulfate resistance and rebar corrosion, the effect of the fly ash with different of CaSO3·1/2H2O on material properties are studied. The results show that: compared with ordinary fly ash, the desulphurization ash contained 4~12% CaSO3·1/2H2O can improve workability, but it has a 4% threshold, over critical value, the improving ability declined; secondly increasing the content of CaSO3·1/2H2O in desulphurization ash can decrease strength, and while the effect of 7 day strength is higher than 28 days’; Thirdly, with the increase of calcium sulfite, the desulphurization can decrease resistance to sulfate attack , especially for more than content of 8% CaSO3·1/2H2O , but it is harmless for steel rebar.
Experimental Method and Research Evolution of Strength Prediction of Cement Concrete
Authors: Wang Zheng Jun , Jin Xiao Ou , Fu Guo Qiang , Sun Dian Min
Published: May 2011

That griping and predicting concrete strength is crucial importance for shorten design cycle of cement concrete proportion and control efficiently key construction node in time. The paper exposited systematically experimental method of strength estimation of cement concrete and corresponding research progress at present, and the prospect was also analyzed. It is very necessary to promote research work of experiment and analysis method because strength estimation of cement concrete is paramount. It has important meaning for delving into the aspect through above discussion in the future.
Damage Assessment of a Prestressed Simply Supported Bridge Using Microwave Interferometer
Authors: Cheng Chia Chi , Yu Chih Peng , Hsu Keng Tsang
Published: May 2011

The microwave interferometer was used for monitoring the behavior of a simply supported bridge under various loading cases. The instrument has a 1-D imaging capability for remotely measuring the displacements of multiple positions simultaneously. The loading cases include truck placed at the middle of the span, driven with variant speeds to generate ambient vibration of the span, driven through with a constant speed, and abruptly stopped at the middle to obtain the damping characteristics of the span. As the bridge has been in operation for 50 years, weak bearing stiffness for the support at abutment and possible fatigue fracture of a roller support above a pier was found from this investigation.
The Purpose and Main Basis of House Layout Analysis in Interior Design
Authors: Liu Chao Ying
Published: May 2011

The analysis of owners’ house layout is an important part of Interior design. Designers, by analyzing and evaluating objectively the house layout that is provided by the house owners, put forward a best design. The quality of original house layout is determined by house elements and environmental elements. Interior designers examine mainly houses factors and also take into account enviromental factors. The main purpose of this paper is to discusse the 12 house elements and the main aspects of environmental elements in analysis of house layout, and to give pondered suggestion.
Embedded Sensor for Detecting Corrosion of Reinforcement in Concrete
Authors: Ismail Mohammad , Siti Fatimah A.R. , Muhammad Bala , Norhazilan Md. Noor , Bakhtiar Hazri
Published: May 2011

Corrosion of reinforcement is a worldwide problem which causes premature degradations in reinforced concrete structures. Monitoring reinforcement corrosion in concrete can be achieved by embedding corrosion sensor within the concrete cover. In this research, capacitance-based embedded sensor was developed to monitor corrosion potential (Ecorr) and corrosion rate (Icorr) parameters of reinforcement continuously. The sensors were tied to the reinforcement and embedded in concrete slab specimens followed by immersion into NaCl solution for 70 days. During this period, corrosion parameters were weekly recorded. At the same time, half-cell corrosion testing using Portable SRI-CMIII was conducted for calibration purpose. From the research, it was observed that the patterns ofEcorrandIcorrshown by the embedded sensors were similar to that of portable SRI-CMIII device - an indication of suitability of the embedded sensor towards sensing existing corrosion activities around the embedded steel bars. Eventually, the bars were found corroded from the broken specimens to confirm the detection of corrosion activities as recorded by the sensors.
Technical Viability Analysis for the Use of Milk Residue in the Consolidation of Taipa in Historic Constructions
Authors: Cocco Maria Dolores Alves , Gonçalves Gabriella Patto Xavier
Published: May 2011

The objective of the study was to analyze the composition of mortar in order to enhance the use of milk serum and its application in earth constructions. Development of the study involved, initially, a bibliographic review and identification of dairy industry producers in the Paraiba Valley, São Paulo, with milk residue storage facilities. The next stage consisted in the preparation of three adobe molds, based on technical reproductions, of the composition of historic constructions. Subsequently, the molds were submitted to laboratory tests: preservation and compression resistance. This was followed by execution of the mortar with milk serum and bacteriological tests, anchoring, and plasticity through the application of mortar. The adobe molds were observed over a period of 15 days, with even the cracked molds shown to be useful for purposes of simulating risk situations. The technical viability analysis of the sample milk serum mortar applied to a historic construction and exposed to the natural elements for a period of 1 year revealed no deformities. After a full year of research, we found the presence of acid milk residue to be a major concern among dairy producers. Further, the difference between acid and sweet milk serum gave rise to a new challenge given the different chemical properties of the two serum types, which can alter the structure of the mortar and its efficacy. To this end, the research work was extended into 2009 with implementation of a new stage aimed at adapting Brazilian technical standards through a technical evaluation of historic mortar and the applicability of acid serum to the residue process.
High Strain Low Cycle Fatigue and Anti-Seismic Behavior of HRB400 QST Reinforced Steel Bars
Authors: Lv Yu Kun , Sheng Guang Min , Xue Hao Fei
Published: May 2011

Based on the failure model of building structural steels under earthquake loading, High strain low cycle fatigue properties of HRB400QST (yield strength grade 400MPa, Quenched and Self Tempered) reinforced steel bars with diameters of 20mm and 16mm(unmachined) and HRB400V-N MA(microalloying)with diameters of 16mm (unmachined) were investigated. Based on the tests of total strain controlling, cycle strain response character of three kinds of steel bars and the relationship between cyclic stress and strain were researched. Hollomon and Coffin-Manson formulas were used to induce fatigue life formulas of three kinds of steel bars, and then the values of σa·Δεt were gained when Nf =100, calculated results show that the high strain low cycle fatigue properties of HRB400V-N MA rebars tested are much better than HRB400QST steel bars. Rupture surface scan reveals that surface hardened layer will reduce the cyclic toughness, and is bad for the anti-seismic performance.
Chloride Diffusivity in Cracked Concrete
Authors: Zhang Shi Ping , Zong Lan , Liu Jia Ping
Published: May 2011

A detailed observation on the penetration profile of chloride ions through a crack in concrete structures was carried out. Cracks were induced using a splitting tensile test, and average crack width was measured using an image analysis technique. Chemical analysis tests were conducted on cracked specimens, which were exposed to NaCl solution at a temperature of 20°C, after being cured for 28d. The results showed that the concrete specimens having cracks showed rapid penetration of chloride ion. The diffusion coefficient calculated according to Fick’s law also indicated that the chloride permeability increased with the increasing crack width.
Juniper Timber: Potentiality of a Vernacular Raw Material
Authors: Ruiz Checa José Ramón , Cristini Valentina
Published: May 2011

This research presents some features about juniper timber, above all related with aspects of its structural use (for supports, pillars, beams, roofs...) in some vernacular architecture. Therefore, a special attention is driven to botanical, technical, mechanical features, typical for this type of rare wood. Its traditional use in the Iberian Peninsula and throughout the Mediterranean Basin is still visible in some cases of study, presented in the research. Good constructive qualities make juniper timber a great candidate for further test-researches and experiments, focalized on the family of traditional and”ever green “constructive materials.
The Research on the Airflow Organization of Residential Kitchen and how to Introduce Make-Up Air
Authors: Shang Shao Wen , Li Xiao Yun , Guo Hai Feng
Published: May 2011

This thesis analyzes the exhaust system of residential kitchen existing problems of indoor air quality. Discusses how to making up air to balance indoor air, eliminate the traditional system defects, through in the hearth additional secondary air tuyere through using the CFD----fluent6.2 simulation software simulates the airflow organization of the kitchen exhaust system if making up air . Analyze the kitchen indoor airflow velocity distribution, and the pressure distribution and velocity vector in the different condition. Under the action of differential pressure, outdoor air is sucked into the kitchen so as to achieve the reasonably airflow organization and get rid of foul gas effectively.
Research on FRP-Reinforced Concrete Exposure Test
Authors: Chen Ye Fan , Chen Chao He , Wang Hong , Zhang Chuan Min
Published: May 2011

The paper makes an analysis of the selected location and feasibility of the exposure test ground in the real marine environment, and the endurance test of the FRP- reinforced concrete built-up beam has been carried out on the exposure test ground. After 6 month and 12 month’s exposure test, the beams' mechanic performance and the chloride ion content in different depths have been determined. The results show that after the exposure test, the beams' ultimate capacity has been greatly decreased to a certain extent, and the FRP board can effectively prevent chloride from penetrating.
Prediction of Cement Compressive Strength Based on Accelerated Curing Method
Authors: Luo Yong Hui , Gao Zhen Guo , Miao Guo Lin
Published: May 2011

Prediction of cement compressive strength was studied with accelerated curing methods, e.g. warm water and boiling water curing. The results indicate that fineness and the type of cements is few influencing on the 28-day compressive strength, and the difference is not distinct between the two methods. The boiling water fast-curing method is recommended since it doesn’t need additional equipments and has the advantage of convenient and high-speed. The prediction equation adopts linear model, and robust estimation of parameters is also applied to eliminate influences of outliers.
Analysis of Elastic Beam Subjected to Moving Dynamic Loads
Authors: Wang Ren Zuo , Chen Shi Kai , Wang Chung Yue , Lin Bin Chin
Published: May 2011

The main object of this paper is to apply the vector form intrinsic finite element (VFIFE, or V-5) techniques in nonlinear large deformation dynamic analysis for the responses of moving loads on rigid frame structures. In this study, the simulation of moving loading is brought into the vector form intrinsic finite element method. It can effectively simulate the moving load. Comparing the results of the numerical simulations by VFIFE with the results obtained from other literatures, they are very close. It proved that VFIFE can effectively simulate the nonlinear large deformation dynamic problem.
The Study of the Railway Tunnel on the Area of Wall Rock Pre-Injection
Authors: Su Hui Feng , Liu Wei Ning
Published: May 2011

During the tunnel’s construction, pre-inject to form loop in wall rock of the fault fracture and karst-developed area where there is abundant water. To reduce the quantity of seepage for lining, simultaneity, set up drainage system to drain the rest of water to achieve its purpose that reduce the press of external water and control drainage with effort. According to the principle of elastic-plastic, the paper analyses and designs the thickness optimization based on the status change of plastic zone during excavating tunnel. The result indicates that the pre-injection loop of the single electrified railway tunnel with standard V level is ranging between 4m and 8m when leave out of consideration of external water load. Otherwise the thickness optimization is around 6m for the deep-buried 200m tunnel.
Construction Techniques of Deep Diaphragm Wall in the Yellow River-Crossing Project in South-to-North Water Transfer
Authors: Rui Da Hu , Wu Qing Hong , Cao Zhen Feng , Zhao Yu Xia , Li Guang Fan
Published: May 2011

Yellow River-Crossing Project in South-to-North Water Transfer approach through the use of shield tunnel and its north bank departure shaft adopts diaphragm wall as enclosure structure. The depth of continuous wall of its shielding starting shaft is 76.6m, which is the deepest at present in china. The continuous diaphragm wall travels through the layer of silver sand, medium sand and loam from top to bottom, where the geological conditions are poor with large difficulty of construction. This paper sets forth construction of guide wall, reinforcing measures before construction, Trenching process, groove segment connections, innovative technologies of uplifting huge reinforcing cage and so on, which will provide guidance and lessons for the similar project
Large Deflection of Tip Loaded Beam with Differential Transformation Method
Authors: Xiao Yi
Published: May 2011

This paper deals with large deflection problem of a cantilever beam with a constant section under the action of a transverse tip load. The differential transformation method (DTM) is used to solve the nonlinear differential equation governing the problem. An approach treats trigonometric nonlinearity is used in DTM. The results obtained from DTM are compared with those results obtained by the finite difference method and they agree well.
Study on Simulation and Stability Analysis of Subway Station Excavation from the Vertical Construction Well
Authors: Xie Jin Shui , Bai Ming Zhou , Xu Zhao Yi
Published: May 2011

Beijing subway Huangzhuang stations is cross-transfer station. It has a complex tunneling structure. The characteristics of the reverse construction vertical well was been thinking in the course of excavation design. The vertical well excavation and support method, horizontal wells channel excavation and support methods, the main station pilot tunnel excavation and support methods were researched to determine in detail. In order to analysis and evaluation the feasibility of excavation and getting into hole, FLAC3D numerical simulation analysis method was applied to do simulation of the vertical well, horizontal channel and the main cavern excavation. All detail construction course of these three-part were been studied. Excavation and supporting method and progress were all included. The ground surface subsidence, deformation of support structure and strengthen structure were been got. On the condition of the vertical well support structure destruction caused by the horizontal guide hole excavation and the group cave effect caused by guiding cave excavation in main station underground building, the support structure and ground soil stability were studied. The research result gave the base technical support for the project optimization design and construction security.
Research on the Application of Compound Admixture in the Freezing Mine Shaft Lining Concrete
Authors: Zong Xiang
Published: May 2011

In order to achieve the setting and hardening of mine shaft lining concrete under the minus temperature in freezing construction and to meet the demands of every performance of concrete, the technique of compounding air entraining admixture and antifreezing admixture and early strength water reducing admixture was applied in this research. Based on the orthogonal experimental design, several mix proportions of compound admixture for early strength liquid mine shaft lining concrete were developed in the laboratory. The data collected in this research provide reference for the optimum mix proportion of the adulteration quantity of the concrete admixture. The results show that the 2.1％ amount of compound antifreezing admixture achieves favorable effects of liquid, early strength, freezing prevention and antifreezing.
In Situ Test and Mechanical Analysis of Multi-Arch Tunnel with Large Section in Soft and Weak Rock Mass
Authors: Liu Tong , Dong Zi Chao , Yang Hai Yong
Published: May 2011

According to the characteristic of multi-arch highway tunnel,based on a practice engineering, the monitoring work was consisted of four sections:the displacement of surrounding rock; such as crown settlement, displacement of the ground, displacement of inner surrounding rock; that of stress and stain of support structure; that of force in middle-wall. In course of construction,monitoring data was analyzed in time.Structural timbering parameters were modified in response to abnormal monitoring data in order to guarantee safety.the testing results of the safety monitoring system are satisfactory, which serves as a symbol of our research work. Thus, our engineering practice has proved the applicability and feasibility of the safety monitoring and information construction methods.
Experimental Investigation on the Strengthening Composite Beam by Shaped-Steel under R.C Beam Jointed with Short Welding Rebar
Authors: Gao Li Tang , Shan Qi Yun , Wu Tai Wei
Published: May 2011

This paper presents the experimental investigation result from a composite beam strengthened by shaped-steel underpinning (CBSSU) test. There were 3 specimens with one was common R.C beam to compare and others were strengthened by shaped-steel underpinning and jointed with short welding rebars. The main emphasis in undertaking this test was to show the effect of short welding rebars in the strengthening beams and collect more detailed data on the performance of CBSSU such as load capacities, load-deformation behaviors, slipping between shaped-steel and R.C beams, stresses distribution and failure mode. The test shows that the short welding rebars was effective to improve the bearing capacity and stiffness. With limited increase in height of the beam can substantially increase the ultimate flexural capacity and flexural rigidity. The cracks of the beam can also be controlled effectively.
A Smart Base-Isolation Using Piezoelectric Friction Damper
Authors: Dai Na Xin , Tan Ping , Zhou Fu Lin
Published: May 2011

A smart base-isolation system, composed of low damping bearings and piezoelectric friction damper is studied in this paper. The semi-active piezoelectric friction damper (PFD[1]) is proposed for control of peak dynamic response of seismic-excited structures. In the proposed PFD device, the friction force between two sliding plates is regulated by controlling the normal force using piezoelectricity across the damper, and its advantage is that its operation requires only minimal external power. A high efficient control algorithm is proposed for the semi-active control of the friction damper using a simple static output. The effectiveness of the PFD device and the control strategy in reducing the peak dynamic response of structures is investigated through an application to a 5-story base-isolated building. Numerical results demonstrate that the proposed PFD device and the control strategy are effective in reducing the peak drift of rubber-bearings of the base-isolated building subject to earthquakes.
Elasto-Plastic Behavior of Doubler Plate Reinforced Tubular T-Joints
Authors: Sui Wei Ning , Wang Zhan Fei
Published: May 2011

The aim of this paper is to study elasto-plastic behavior of the doubler plate reinforced tubular T-joints (DP-T-joints) subjected to axial tension or compression loading at the top of brace. Finite-element method is adopted in the numerical parametric studies to evaluate the ultimate strength of DP-T-joints. To verify numerical analysis, a typical full-scale doubler plate reinforced tubular T joints experimental study has been modeled using ABAQUS package. The load-displacement curves of the numerical results agree with the experiment curve very well. Then, affect of parameter (doubler plate width parameter α, doubler plate length parameter Δ, doubler plate to chord wall thickness ratio λ) on the elasto-plastic behavior has been investigated.
Study on Seismic Performance of Light Wall Modular Composed of Oriented Structural Straw Board and Tennon-and-Mortise Connection Frame
Authors: Xie Qi Fang , Xiong Hai Bei , Lu Xi Lin
Published: May 2011

A developed light wall composed of oriented structural straw board (OSSB) and tennon-and-mortise connection wood frame (TMCWF) was introduced. The wall build-up with the wall-modular, top plate and sill plate, the wood frame members of a modular are connected with tennon-and-mortise, and the panel is OSSB. The seismic behavior of the light wall modular composed of OSSB and TMCWF was tested under low-cyclic loading based on seven modular-wall specimens, which have various spaces of vertical frame members, panel type, panel thickness, space of nails and vertical loads. The performances of the specimens such as the failure models, hysteretic curves, shear capacity and ductility are obtained. Experimental results show that the final failure is induced chiefly by penetrating the panels for nails; the hysteretic curves are typically reversed S-shaped; the type of panel, the thickness of panel, the space of panel nails are the major factors to influence the shear strength of the modular-wall; the rigidity is big at the initial stage and then reduced sharply; the displacement ductility factors of the wall-modular calculated with specification method are low.
Establishment of Vibration Differential Equation and Analysis of Dynamics Characteristics for Curved Beam
Authors: Song Yu Min , Wu Ding Jun
Published: May 2011

In this paper, a differential segment of curved beam in the vibration state is analyzed, and the internal force equilibrium equations are established, then the vibration differential equations of curved beam are derived by considering Timoshenko’s geometric equations and physical equations. The vibration differential equations derived are similar to the Vlasov’s static differential equation of curved beam. By analyzing the vibration differential equations, some characteristics of vibration are obtained, and ideas of solving the vibration differential equations are also proposed. The vibration differential equations of curved beam can be reduced to those of corresponding straight beams, validating the derived vibration differential equation of curved beam.
Taizhou Bridge South Anchor Caisson Construction Drainage System Optimization Model of Settlement and Deformation as Constraint Conditions
Authors: Zhao Yan Rong , Zhou Zhi Fang
Published: May 2011

Since construction drainage will inevitably cause ground settlement, it is necessary that a system optimization model is established with source (sink) distribution and intensity being the object function, minimum requirements of settlement and deformation of surroundings caused by draining and dynamic water levels during different working procedures being constraints, and the design parameter of pumping (injection) wells being the variable. The system optimization model solved the problem of which Taizhou bridge south anchor caisson foundation construction drainage induced settlement, so as to lower the damage of surrounding buildings. So the system optimization model provides a new method for active control over settlement during draining. Such a method of drainage based on system optimization model should be of significance for similar projects involving drainage.
A New Elastic-Plasticity Yield Criterion for Rock and Soil
Authors: Liu Jian Hua , Zhu Wei Shen
Published: May 2011

In this present paper a new yield criterion called M-D criterion is established based on the average of Mohr-Coulomb and Drucker-Prager criterion. The new M-D criterion is integrated with a revised FLAC3D method for mechanical analysis. Comparisons between the results of M-D, Mohr-Coulomb and Drucker-Prager are made by cases study. The study shows that results of M-D criterion are basically between the results of Mohr-Coulomb and Drucker-Prager and have the feature of being medial in quantity.
Numerical Simulation Algorithm for the Forming Process of Tensile Cable-Strut Structure
Authors: Zhao Jun Zhao , Chen Wu Jun , Fu Gong Yi , Li Rui Xiong
Published: May 2011

Numerical simulation of forming process is an issue that finds the solution of a series of unstable equilibrium states of cable-strut tensile structures with specific unstressed length. This is a long well unsolved theoretic question, which mostly lies in the couple of mechanism and elastic deformation. On the basis of the unstressed length, the theoretic parabolic curve element was adopted to simulate the cable with elastic tension and deformation. The vector of unbalance nodal force was subsequently formulated with the explicit branch-node matrix of topology in force-density method. And the dynamical relaxation method was used to solve the nonlinear equation to avoid the singular stiffness of equation. Numerical examples indicated that the proposed algorithm could calculate the unstable equilibrium state and simulate the forming process with the unstressed length of the active cables changing, and has some theoretical significance.
Formation and Evolution of Chaancun Landslide in Dalian City, China
Authors: Xu Yan , Nie Lei , Dai Shu Lin , Zhang Min
Published: May 2011

Chaancun landslide in Dalian city is located at the heartland of Dalian Xicheng International tourism business district which is the throat position of tourist attractions. Development of tourist attractions is influenced by Chaancun landslide. Formation and evolution of landslide have direct influence on estimation of landslide stability and prevention effect. Based on investigation and analysis, it is concluded that the current active landslide which is induced by human activity is a part of ancient landslide and it is important to note that the stability of both the current active landslide and the ancient landslide should be taken into account when the landslide is mitigated.
Study on the Load Test of Old Bridge
Authors: Zhang Ping , Wang Lei , Li Dong Xiao
Published: May 2011

It may appear different diseases after years of operation on old bridges. In order to understand the actual working condition and the bearing capacity of the bridge, the static and dynamic tests are taken. It describes the principle and methods for the load test via taking Banlashan Arch Bridge for example in this paper. The stiffness, strength and dynamic characteristics of bridge structure are measured, and the maintenance and reinforcing schemes are proposed, according to the results of static and dynamic load tests. Through analyzing the tests, the data and information of bridge can be accumulated, and the mechanical characteristics of this kind of bridge are discussed.
Experimental Research on Instability Activation Mechanism of Old Goaf Overburden Rock
Authors: Zhang Yong Bo
Published: May 2011

Taking the 2204 working face of Xinzhi Colliery in Huozhou as the background, through experiment of analog simulation, analyze the structure type of old goaf overburden rock breakage, instability activation mechanism of overburden rock and instability form and condition for stability of voussoir beam of old goaf. As the result, after mining and breakage, the rock mass structure of old goaf and overburden rock can be divided four types. This secondary rock structure has an important effect on old goaf activation. The existence form will decide the basic characteristic of old goaf activation. Through the mechanics analysis on voussoir beam of old goaf , it is obtained that instability due to sliding mainly depend upon the physical mechanics characteristic of key block and sideward rock, W/T value, and additional load of building on surface and so on. Rotational instability is related to the physical mechanics characteristic of key block and sideward rock and thick and length ratio h/l of the hanging rock
Nonlinear Finite Element Analysis of Concrete Continuous Beams with External CFRP Prestressed Tendons
Authors: Zeng Xiao Qing , Wang Xin Ding , Tang Qiu Hua
Published: May 2011

The article makes a simulation on the external CFRP prestressed reinforced concrete continuous beams with ANSYS, the beams which had made analysis by Kiang Hwee Tan and Robert A. Tjandra. There is a little difference between the results of simulation and experimental results. It shows the reliability of simulation on concrete continuous beams with ANSYS. Then it makes a finite element analysis about parameters of the bending properties of continuous beams. It could provide relevant information about bending performance of concrete continuous beams with external CFRP prestressed tendons.
Experimental Study on the Influence of Temperature on Shale Mechanical Properties under Conventional Triaxial Compression
Authors: Meng Lu Bo , Li Tian Bin , Jiang Liang Wen , Ma Hong Min
Published: May 2011

High temperature conventional triaxial compression test of shale are carried out by the MTS815 servo-controlled testing machine, based on the experimental results, the relationships between temperature and shale peak strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle are investigated. Although the experimental results are discrete comparatively, the general law is obvious. When the confining pressure imposed on shale is constant and the temperature changes form 25°C to 120°C, with the increasing of the temperature, the triaxial compression strength, shear strength gradually increase, while average elastic modulus, Poisson's ratio has a slightly decrease. The thermal stress generated by the high temperature plays a role to accommodate the deformation and the function of preventing crack propagation, thus the bearing capacity of shale samples are strengthened. But the influence of temperature on shale mechanical properties mutates when the temperature is at 80°C. Shale peak strength dramatically decreased, average elastic modulus decreased slightly, and Poisson's ratio also increased slightly, which indicated that at 80°C, different thermal expansivity of mineral particles of shale may cause cross-grain boundary thermal expansion incongruous, creating additional thermal stress, thus the sample’s bearing capacity decreased.
The Analysis of Stress Distribution of Hammer Bottom during Dynamic Compaction on Sandy Soil Foundation
Authors: Wu Jian Qi , Deng Jian Hong , Wang Xiao Ping
Published: May 2011

Obtained stress distribution of hammer bottom according to the analysis of horizontal and vertical red sandstone fill dry density of the hammer bottom after dynamic compaction; affirmed the stress distribution situation of the hammer bottom through comparative analysis of the test results by laboratory and field monitoring.
Risk Evaluation of Environmental Monitoring Indexes for Deep Excavation
Authors: Zhang Jiao
Published: May 2011

The risk evaluation of environmental monitoring indexes during deep excavation was systematically investigated and applied to a real project. The risk analysis was carried out based on the collected environmental monitoring data. The potential accidents which may be caused by the abnormal environmental monitoring indexes were analyzed. The risk sources which may arouse the value variation of the environmental monitoring indexes were disclosed. The dynamic controlling measurements for the risk sources were suggested. The successful application of the dynamic method to the real project further verified its feasibility.