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15 June 2010, Volume 29 Issue 3 Previous Issue    Next Issue

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Reach on Dynamic Behavior and Parameter Influence of Single Pylon Cable-Stayed and Continuous Rigid-Frame Composite Bridge FENG Dong-ming, LI Ai-qun, LI Jian-hui, YANG Guang 2010, 29(3): 329-332.  Abstract ( )   PDF (1236KB) ( )   Ihe dynarmic characteristics of the first single pylon cable-stayed and continuous rigid-frame hybrid girder bridge in China are analyzed on the basis of Midas/Civi12006.The strategies of modeling 3D FEM model in simulating process are introduced.The self-vibration behavior of this unique bridge is analyzed by adopting the subspace iteration method,the first 10 0rder frequencies and corresponding vibration modes are also given. Meanwhile,different structural parameters, such as dead load intensity and elastic modulus, which have influence on dynamic characteristics, are calculated respectively Fur- thermore, its rule is discussed and analyzed. The calculating results indicate that the cable-stayed continuous rigid-frame hybrid bridge possesses both features of the cable-stayed bridge and the continuous rigid-frame bridge;and the hybrid bridge is greatly influenced by dead load intensity and elastic modulus. The analysis results mentioned above provide refer- ence for natural vibration analysis and earthquake-resistance design of this hybrid bridge. References | Related Articles | Metrics

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Structural Analysis on Solid-Type Arch Bridge Considering the Confining Pressure Caused by Infilling FAN Liang, HUANG Man 2010, 29(3): 333-335.  Abstract ( )   PDF (1157KB) ( )   In order to check the safety of a 3-span solid-type arch stone bridge-Chongqing Tiaoshi Bridge,special trailers are used to pass the bridge.The structure analylsis methods of solid-type arch stone brilge are discussed, particularly,the simulation in structure analysis and the interaction of the ring and the infilling are focused. The influencing way of the infilling on the main arch ring is analyzed. Furthermore,the loading transferring and the confining pressure effect of the arch ring are taken into consideration by simulating the infilling through plate element;meanwhile, the way of connecting arch ring and the infilling through the two-way compression rod only is also used.The FEM results verify the feasibility of the model mentioned above. And it is found that the above-mentioned interaction can markedly improve the bearing capacity and stability of arch stone bridge. References | Related Articles | Metrics

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Influence Analysis on Main Cable Angle of Side Span of Suspension Bridge LIN Qia,CUI Bing,TANG Mao-lin,SHEN Rui-li,TONG Yu-qiang 2010, 29(3): 336-339.  Abstract ( )   PDF (902KB) ( )   In oreder to study the influence of main cable angle of side span in suspension bridge, Xihoumen Suspension Bridge is taken as the protype,its finite element model is established by using bridge nonlinear analysis system BNLAS, which is developed by Southwest jiaotong University. This model is about a twin-tower single-span suspension bridge and its main cable span is 1650m, which has a single-span simply supported girder. Then, the influence of main cable angle on the force of suspension bridge is analyzed, through camparing the force changes of suspension bridge with different main ca- ble lengths of side spans References | Related Articles | Metrics

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Stability Analysis on Large-Span CFST Arch Bridge at Construction Stage SHEN Pei-wen,ZHOU Shui-xing,LUO Fei 2010, 29(3): 340-343.  Abstract ( )   PDF (650KB) ( )   The stability of concrete filled steel tubular (CFST) arch bridge at construction stage is concerned by engineers. Based on the Xinlongmen Bridge, considering the constititive relationship between steel tube and concrete, spatial finite el- ement model is established by ANSYS. The stability of Xinlongmen Bridge at construction phase is analyzed from three as- pects of eigenvalue buckling, geometric nonlinear instability, geometric and material double nonlinear instability.The re- sults show that CFST arch bridge is greatly influenced by the stability during consruction stage, and there is a downward trend of stability coefficient; meanwhile, a large difference exists between double nonlinear srability coefficients and eigen- value buckling coefficients which can get up to 30% at maximun. References | Related Articles | Metrics

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Stability Analysis on Large Span Concrete-Filled Steel Tube Arch Bridge Based on Slip Theory ZENG De-rong,LI Jie 2010, 29(3): 344-347.  Abstract ( )   PDF (996KB) ( )   The concrete-filled steel tube structure obtains the widespread application in the bridge and the architecture engi- neering, the bonding force between the concrete and steel tube influences both he bearing capacity and stability of the structure. The study of stability of the structure is based on the bond-slip theory between the concrete and steel pipe, the construction relations are established,and the bond-slip unit is realized by using existing structure anarysis FEM software. The influence of bonding degree between concrete and steel tube on the bulking loading and safety stability coefficients of the concrete-filled steel tube arch bridge is studied by a case stingudy. The findings indicate that the stability of arch bridge is inclined to no safety,if the bridge is based on the design with close bonding and no relative slip. References | Related Articles | Metrics

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Analysis on Pouring Sequence of CFST Arch Bridge with Six Tubes TONG Jian-sheng,ZHOU Shui-xing,SUN Ce-shi 2010, 29(3): 348-451.  Abstract ( )   PDF (1068KB) ( )   Taking Xiaohe Bridge, which is under construction, as a project exanple, the effects of deformation and stress of the main arch ring causecl by different arch-thickness coefficients and pouring sequences are discussed. BY using the AP_ DL Language of ANSYS, a program is developed, which is completed by five different pouring sequences and three arc- thickness coeffcients such as 0.316,0.7and 1.0. The computing results show that he effect of pouring sequences is slight on the deformation and stress of the main arch ring but is remarkable on the stress of core concrete; and the stress of core concrete varies with the pouring sequence. The changes of arch thickness coefficients don't have obvious influences on Xiaohe Bridge. References | Related Articles | Metrics

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Local Force Analysis of Steel-Box Girder Bridge with Incremental Launching Construction by Vertical Curve of Variable Curvature ZHOU Ye-fei,GONG Jing-min 2010, 29(3): 352-357.  Abstract ( )   PDF (1546KB) ( )   The non-stress aligument of present long-span steel box girder bridges is generally a single radius of vertical curve. The non-stress alignment of steel box girder of Hangzhou Jianglong Bridge is a continous variablely curved vertical curve. The feature of variable curvature not only changes the incremental launching radius of vertical curve, but also makes the displacament of steel box girder at slide path corner obvious. Therefor,the new requirement to construct the incremen- tal launching slide path is put forward:the alignment of rubber surface should automatically adapt to the changes of grider. The security of steel box girder forcing is essentialto the success of the incremental launching. 3D finite element analysis on local steel box girder of the slide path is carried out by ANSYS, and stress distributions of various components of steel box girder under seven typical operation conditions are comparied. The analysis draws a conclusion that the counterforce of tem- porary pier and ne corner displacement of the steel box girder on the slide are critical factors to affect the local stress of the steel box girder. References | Related Articles | Metrics

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Analysis on Damage of Near-Faultage Bridges in Wenchuan Earthquake LEI Tao,LI Bi-xiong,CAO Peng-jie,SHUN Yuan-kun 2010, 29(3): 358-362.  Abstract ( )   PDF (1748KB) ( )   Transport system has been severely damaged during the M8.0 Wenchuan earthquake; several bridges near the faultage are damaged severely and even collapsed, which lays great impact on the rescue and reconstruction after the earthquake. With the site characteristics of near-faultage, the damage of several near-faultage bridges is analyzed h detail.At the same time, some reasonable suggestions for future seismic design of bridges are presented as follow: firstly,choosing a good site far from the faultage is very important for the bridge construction; secondly the reasonable seismic structure of bridge can reduce the bi-dirctional seismic action;meanwhile, the effect of vertical seismic action on bridges should be fully considered; thirdly, bridges should be designed in ductility in order to avoid the fragile destruction on piers; finally,designing piers reasonably and reinforcing the connections of bridge blocks can effectively prevent girder from falling in the earthquake. References | Related Articles | Metrics

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Stability Analysis on Large Section Tunnel with Double-Side-Drift Method GAO Feng,TAN Xu-kai 2010, 29(3): 363-366.  Abstract ( )   PDF (1287KB) ( )   Taing Shawan Tunnel as background, the influence of tunnel's stability resulting from the time of closing the support in large section tunnel with double-side-drift method is studied by finite element software ANSYS with the load-releasing method. Through analyzing vertical displacement of the vault, horizontal displacement of the middle point of sidewall, plastic zone of surrounding rock and stresses of preliminary lining, the result shows that sealing the primary shoring quickly is favorable to control the stresses and displacements of the tunnel. So in construction process the distance between adjacent excavation faces should be shortened and the speed of closure should be stepped up to achieve stability of the tunnel. The state of reinforcing parts of surrounding rock is simulated in order to further search for some way to improve the stresses of the tunnel.It is shown that reinforcing the surrounding rock near the contact area of the temporary support and preliminary lining will improve the stresses condition o f the tunnel.Meanwhile, the contact area of the temporary support and preliminary lining, where a great deal of concentrated tensile stress appears, should be paid attention to in the design and construction process. References | Related Articles | Metrics

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Experimental Study on Application of Haydite Concrete to Tunnel Pavement BAI Shan-yun,LIU Jun,LING Tian-qing,DONG Qiang,WANG Rui-yan,ZHENG Zhi-neng 2010, 29(3): 367-370.  Abstract ( )   PDF (375KB) ( )   The influence of haydite' s proportion on the rupture modulus and abrasion resistance performance of the concrete has been researched by experiment.Furthermore, through the application of haydite concrete to the tunnel pavement, it is proved that the haydite concrete can reduce vehicle noises, which is based on the condition that the slab's mechanical performance and abrasion resistance performance are ensured. References | Related Articles | Metrics

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Load Stress Analysis on Roller Compacted Concrete Pavement ZHANG Pei-jia,Fang Jian,HE Zhao-yi,LU Zhao-feng,WANG Guo-wei 2010, 29(3): 371-374.  Abstract ( )   PDF (1018KB) ( )   Using 3D finite element technology, 3D pavement model of double-layer plate on elastic foundation is established, and the loading tensile stress of composite roller compacted concrete pavement is analyzed under various factors, including the contact state between layers,the critical load position, the pavement modulus and thickness, the base modulus and thickness of cement stabilized crushed stone as well as the subgrade modulus.Finally, the theoretical computation of load stress and thermal stress as well as the rebound deflection results of the test road offer references to the road performance of typical structure. References | Related Articles | Metrics

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Analysis of Creep Based on Concrete Microstructure TAN Jing-wen,XIANG Zhong-fu,XU Hang,YAN Nan 2010, 29(3): 375-378.  Abstract ( )   PDF (384KB) ( )   The informed methods of calculating concrete creep are analyzed, and a new calculation model of creep is proposed after synthesizing the research achievements of others.This method distinguishes elasticity of aggregate from hysteretic elasticity of mortar matrix; adopts Kelvin chain to display the aging action and the time of hysteresis on concrete;introduces time- ratio factor to take account of the response speed of time on hysteresis.Through the analysis in the case study, the results indicate that the variable process of concrete experiences hysteretic elasticity all time, but doesn' t do at the dead state;the time-ratio factor affects more obviously on concrete material characteristics under structure unloading or reloading conditions. References | Related Articles | Metrics

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Study on Uni-axial Ratcheting Describing Plastic Modulus of Two-Surface Constitutive Model XIANG Yang-kai,MA Yan-bing1,ZHENG Yi,ZHOU Zhi-xiang 2010, 29(3): 379-382.  Abstract ( )   PDF (1327KB) ( )   The uni-axial ratcheting experiments of two materials under different mean stress and stress amplitude are carried out, and the plastic flow characteristics of experiment results are also analyzed. Both features of the uni-axial ratcheting and different evolution rules of plastic modulus at the symmetric loading points are presented. The nature that the current two?? surface constitutive model fails to describe the ratcheting is also revealed. On the basis mentioned above, a new plastic modulus formula is introduced; meanwhile, the numerical simulation is also carried out. Through the comparative tests carried out between the simulation and the experiment, it is discovered that simulation results matches well with experiment results. So the reasonability of the plastic modulus formula is verified. References | Related Articles | Metrics

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Adhesion Intension between Deformed Steel Bars and Concrete and Its Influencing Factors MA Yan-bing,XIANG Yang-kai,ZENG Jian-min,MAO Zhou-ming 2010, 29(3): 383-386.  Abstract ( )   PDF (1067KB) ( )   The adhesion intension between deformed steel bars and concret is analyzed theoretically Th mugh therough the pull-out tests of the deformation of steel bars wilh different corrosion time, the relationships between adhesion and various influen- cing factors are obtained. Based on the test results and ne statistics analysis, the formula of the adhesion intensity between deformed steel bars after corrosion and concrete is given. The test results lay the foundation for the bearing capacity and du- rability research of the concrete structures; at the same time,they can also be used to study the structure life of bridges etc. References | Related Articles | Metrics

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Study on the Performance of Compound Modified Bitumen Guss Asphalt XUE Xin,WANG Min,GAO Bo,FENG Quan 2010, 29(3): 387-390.  Abstract ( )   PDF (328KB) ( )   Bitumen is especially important to Guss Asphalt (GA). Comparative tests of performance are carried out between the simple common asphalt, lack asphalt compound modified bitumen, sock asphalt compound modified bitumen and polymer compound modified bitumen, which show that compound modified bitumen is more suitable for GA; meanwhile,Lueer, penetration, fatigue and low-temperature bending tests on GA of above three compound modified bitumen are carried out, in order to research their differences of construction, high-temperature, low-temperature and fatigue performance. The results show that: the performance of sock asphalt compound modified bitumen GA is equivalent to lack asphalt compound modified bitumen GA, and polymer compound modified bitumen GA is more suitable for cold regions. References | Related Articles | Metrics

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Study on Performance of Heat-Reflective Coat of Lowering Asphalt Pavement Temperature CAO Xue-juan,TANG Bo-ming,ZHU Hong-zhou 2010, 29(3): 391-393.  Abstract ( )   PDF (1095KB) ( )   A new kind of solar-reflective coat is painted on asphalt pavanent.In surrmer with high temperature, the pavement tamperature can be lowered from 5 to lOoC with this mabrial. The cooling effect is more obvious when it is used on porous asphalt pavement.Furthermore,the pavement performance is also studied. The research results show that the pavement with solar-reflective material has good wearing capacity. With the dosage of coat increasing, the skidding-resistance performance decreases. When the material is used on dense-graded pavanent, the anti-skidding granular should be added.The pavement tamperature can be reduced on account of high reflectivity of coat, which can effectively prevent and lessen the rutting disease of asphalt pavement. References | Related Articles | Metrics

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Evaluation Method of Low-Temperature Anti-cracking Performance of Superpave Asphalt Mixture ZHANG Cai-li,MENG Qing-ying,HAN Sen 2010, 29(3): 394-397.  Abstract ( )   PDF (792KB) ( )   The low-temperature anti-cracking performance of Superpave asphalt mixture is evaluated respectively by low temperature curvature rupture test and thermal stress restrained specimen test (TSRST).The results show that freezing temperature and transition point temperature are the indexes to evaluate the low temperature performance of superpave asphalt mixture.It is also found that the curvature strain energy density used as an evaluation index indicates well the low temperature performance of Superpave asphalt mixture;meanwhile, the test result can accord with the result got by TSRST. References | Related Articles | Metrics

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Influence of Fine Aggregate Particle Size on Viscoelastic Parameters of Asphalt Mortar by Gray Entropy Method YING Rong-hua,HOU Zhao-guang,PANG Hai-feng 2010, 29(3): 398-402.  Abstract ( )   PDF (1256KB) ( )   Uni-axial compression creep test is carried out on asphalt mortar of different fine aggregate compositions, and the results of creep test are fitted by Burgers mode. Then the influence degree of fine aggregate particle size on viscoelastic parametersis analyzed by the gray entropy method,in order to make apreliminary study of the viscoelastic property of asphalt mortar. The results show that:the aggregates ranging from 1.18mm to 2.36mm exert significant influence on viscoelastic parameters E1 , E2 and η2 ;the influence of aggregates smaller than 0.075mm on four viscoelastic parameters takes the second place; the aggregate ranging from 2.36mm to 4.75mm exerts significant influence on viscoelastic parametersη1 . References | Related Articles | Metrics

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Investigation and Analysis of Road Natural Grit in Tibet ZHAO Yi,LIANG Nai-xing,REN Hai-ping,LIU Guang-ming 2010, 29(3): 403-406.  Abstract ( )   PDF (797KB) ( )   Through the investigation of natural grit used as the matErial of the main arterial highway in Tibet,the region research on natural grit in Tibet has been carried out,which is manly based on the climate type. Accorrling to the gradation composition of natural grit at various districts in Tibit,the thickness of the natural grit in Tibet has been analyzed by the method of characteristic aperture passing rate and fineness modulus, Meanwhile, the representative gradation of natral grit in Tibet is proposed References | Related Articles | Metrics

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GIS Study on Chinese Highway Natural Regionalization YANG Hong-zhi,LI Chao,XU Jin-liang 2010, 29(3): 407-412.  Abstract ( )   PDF (3003KB) ( )   Revealing the regional difference of the natural environment of highway engineering is the main task of highway natural regionalization. At the same time, highway natural regionalization can also provide scientific basis for highway construction decision. GIS for natural regionalization of Chinese highway (HR-GIS) can solve the key problem of quantification of regionalization indices.The integration method and the framework of HR-GIS are studied according to the guideline and the research method of natural regionalization for Chinese highway. Based on object-rational model, the spatial database has been built for massive data management.The spatial mining methods suitable for the natural regionalization research are put forward to accomplish quantitative calculation of environmental indices.Using ArcGIS Engine technology, the HR-GIS has been developed and completed, which has realized the functions such as spatial analysis and information inquiry of natural regionalization. References | Related Articles | Metrics

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Methods and Techniques of Landscape Planning and Design for Tourism Highways YAO Yang,TU Shu-rong 2010, 29(3): 413-416.  Abstract ( )   PDF (608KB) ( )   The tourism highway construction plays an important role in boosting regional economy.The landscape planning and design have a great impact on enhancing the tourism highway quality.Starting from the nature and landscape characteristics of the tourism highway, principles, contents and methods of landscape planning and design for tourism highways are discussed systematically.Meanwhile, a new concept for the planning and designing of tourism highways is proposed, which shows the direction of landscape construction for tourism highways. References | Related Articles | Metrics

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Research on the Length of Widening Lane with Left-Turn Signal of Signal Controlled Intersection ZHOU Zheng-dao,ZHOU Wei1,MA Bin,LOU Chen-hui,LUO Xia 2010, 29(3): 417-420.  Abstract ( )   PDF (700KB) ( )   Through mathematical analysis of traffic flow parameters (volume, saturationflowrate, spacing), quantitive research of the length of widening lane with left-turn signal is carried out.Furthermore, the mathematical model is founded,and the computing software is also developed.The reduction factors of capacity at different widening lengths are obtained.vissim simulation is adopted to compare the results before and after optimization, which is verified the correctness and feasibility of the model. References | Related Articles | Metrics

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Influence of Ultra-high Changing Rate of Single-Track Traffic Curve at Mountainous City on Traffic YU Pei 2010, 29(3): 421-424.  Abstract ( )   PDF (448KB) ( )   In the monorail tansport line system at the mounlainous city, indicalors and standards of the rail line are rela- tively lower than those of the subway system , because of the features of single-track system.So lines are showed more flexi bly and therefor, ulha-high,larger and shorter tansition curve as well as the smaller curve radius can be adopted. Based on these characteristics,the turbulence intensity can be controlled by reducing the ultra-high changing rate,so as to en- hance the driving smoothness References | Related Articles | Metrics

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Arterial Highway Safety Evaluation Based on Road and Environment Condition TU Shu-rong,WU Min-gang,CHENG Yong-hua 2010, 29(3): 425-429.  Abstract ( )   PDF (216KB) ( )   Based on the analysis of traffic network characteristics and factors affecthg the road safety, analytical hierarchy process has established safety evaluation system for arterial highways as well as index-measuring approach; in accordance with reality of arterial highway safety evaluation, analytical hierarchy process has also proposed evaluation approaches that cambine qualitative analysis with quantitative coomputation, namely, comprehensive evaluation exponent and fuzzy canpre- hensive evahatian. Through the application of safety evaluation project to a typical section of a main highway in some prov- ince, the rationality and reliability of the proposed approach is verified. References | Related Articles | Metrics

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Evaluation on Application of Bioengineering Techniques to Slope Protection of Baolong Highway SHI Ling,WANG Chang-xian 2010, 29(3): 430-432.  Abstract ( )   PDF (208KB) ( )   To evaluate the protective effect of slope with vegelation and offer theoretical and technical references for the veg- etation restoration and reconstruction of side slopes on Baoteng Highway, the ecological effect of re-vegetation on Baolong Highway side slope is studied.This study is based on the restoration ecological principles of Baolong Highway side slope construction project. The results show that:①the selecticn of vegetation species should be focused on the native-based plant, and alien species with no strong invasive nature can also be selected ②bioengineering techniques for slope protec- tion have limitations and should be combined wih engineering technique;③the relatively steep slope of rock could be con- sidered to set planting trough within the box beam, planting climbers and hanging plants. References | Related Articles | Metrics

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Investigation and Analysis of Road Traffic Accidents after "5.12" Wenchuan Earthquake WANG Hong-ming, WU Wei 2010, 29(3): 433-436.  Abstract ( )   PDF (1145KB) ( )   "5.12" Wenchuan Earthquake has been the earthquake with the highest intensity and the widest destructive range in the mountainous area since our country was founded. In order to research the law that the earthquake affects the road traffic safety, the change of Beichuan county and Anxian county before and after the earthquake is investigated and analyzed. It is found that traffic accidents and casualties in the disaster area are substantially increased than ever before; the accident death rate is enhanced; the transportation mode distribution, the 24-hour distribution, the form distribution and the causes of accidents have also been obviously changed. It is concluded that these changes are related to the road damages and secondary mountainous region disasters caused by the earthquake; they are also related to the path occupied by nontransportation,the traffic capacity rapid ly increased, the time and spatial distribution as well as the composition change of traffic flow; besides, they are related to the weakening of the implement degree of traffic laws and the change of people;s psychology etc. References | Related Articles | Metrics

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Traffic Flow Prediction Based on Multi-scale Analysis and Neural Network HUANG Mei-ling,LU Bai-chuan,TAN Wei 2010, 29(3): 437-440.  Abstract ( )   PDF (1180KB) ( )   Aiming at characteristics of nonlinearity, strong interference and no obvious regularity of traffic flow caused by the complexity and uncertainty of time variance in current traffic system, a new approach is proposed for traffic flow prediction. Firstly, the traffic flow sequence made of different frequencies is decomposed into low and high frequencies in the multi-resolution analysis and the trend components are restored according to the reconstructing principle of wavelet coefficients. Secondly, the artificial neural network is used to forecast these coefficients respectively. Finally, the real detecting traffic data are used to testify the precision of the model.The results show that the forecast model based on multi-scale analysis and neural network has higher accuracy than the traditional artificial neural network model does, and this new model can be used in the dynamic forecast of traffic flow in real time. References | Related Articles | Metrics

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Analysis on Tension-Shear Complex Fracture under Rock Stress and the Calculation of Fracture Direction WANG Kui,ZHAO Ming-jie 2010, 29(3): 441-444.  Abstract ( )   PDF (383KB) ( )   The application of the hydraulic fracturing technique is more and more extensive in geotechnical engineering, but hydraulic fracturing may cause some geology disasters. Therefore, the mechanism of the hydraulic fracturing is a hot topic in geotechnical engineering. The fracture propagation is studied through the principles of the fracture mechanics, the computation formula of the cracking angle of fracture and the critical internal water pressure based on the maximum circumferential stress criterion are deduced. Then, the relation between the critical internal water pressure and the direction of the fracture are analyzed in detail; meanwhile, the fracture location where the hydraulic fracturing is mostly inclined to occur under the tension-shear complex model is obtained. References | Related Articles | Metrics

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Macroscopic Characteristics of Loose Earth in Cyclic Soak at Three Gorges Reservoir Area HE Xiao-ying,TANG Hong-mei,CHEN Hong-kai,LIU Hu-dui 2010, 29(3): 445-449.  Abstract ( )   PDF (850KB) ( )   As the water level of Three Gorges Reservoir has risen up to 175m, it has already caused plenty of geologic disasters, especially caused some occurred disasters to recur. The current researches in this field don't take the influence of cyclical soak on Three Gorges Reservoir's earth into consideration. So the typical loose earth of Three Gorges Reservoir area is adopted, and the earth samples are investigated through a series of tests which are carried out under the condition of native state, longterm soak state and cyclical soak state. Phase's qualitative analysis and quantitative analysis on these earth samples are carried out by poly-crystal X ray diffractometer. Through comparing phase's analysis, the conclusion that the cyclic soak caused by the fluctuation of the water level at reservoir area is an important factor to cause the deterioration of earth structure and intensity is confirmed References | Related Articles | Metrics

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Application of Side-Hole Acoustic Transmission Method to Non-destructive Detection of Driven Piles CHU Guang-hui,XU Xi-bin,WU Tong-qing,LIU Tao 2010, 29(3): 450-453.  Abstract ( )   PDF (571KB) ( )   The basic critical principles and data processing of the side-hole acoustic transmission method are focused. Sidehole acoustic transmission method is a successful application of wave theory to the integrity test of piles. Some corresponding changes of acoustic transm ission method are made to accommodate the detection of the driven pile, which not only preserves the original advantage but also expands its testing scope. References | Related Articles | Metrics

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Design Method of Dredging up of Upper Changjiang River at Flood Season YANG Xiang-fei,ZHANG Jun,ZHOU Lin 2010, 29(3): 454-457.  Abstract ( )   PDF (568KB) ( )   Construction at low water season, stand-down at flood season is a tradition that we use to dredge up the river, but dredging up Tonggu and Saojibei Shoal at flood season has received good treatment effect in the treatment project of Xu- Lu section.Based on the received achievements, the design methods of dredging up river at flood season are discussed, through analyzing the resolutions to difficulties occurring in the engineering construction.The design methods include the key of designing at prophase, the arrangement of working procedure, and the determinant of the adaption of dredge up at flood season etc.Therefore, references are offered to the design method of dredging up the similar shoal in the upper Changjiang River at flood season. References | Related Articles | Metrics

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Re-division of Confluence Patterns of Main Stream and Tributaries of Rivers at Mountainous Area ZHANG Qiang,WANG Ping-yi,LIU Qian-ying 2010, 29(3): 458-460.  Abstract ( )   PDF (309KB) ( )   The current researches on the confluence of main stream and tributaries are carried out from miter-shaped confluence and “Y ”shaped confluence, which doesn't take the real river pattern into consideration. Therefore, these researches can't express the real characteristics of the river confluence at mountainous river. To solve the problem, the traditional forms of confluence need to be re-divided and studied. A lot of information about natural rivers shows that tributaries at the confluence are almost straight types, while main streams at the confluence are always with the bend, straight, or bifurcation form. So the division of confluence patterns in the light of the river patterns has practical values. References | Related Articles | Metrics

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Experimental Study on Energy Dissipation Effect of Chamber Energy Dissipater in Superhigh-Head Lock YANG Zhong-chao,CHEN Ming-dong,YANG Bin,WANG Duo-yin 2010, 29(3): 461-465.  Abstract ( )   PDF (1807KB) ( )   Using advanced measurement equipments such as ADV,the energy dissipation effect of open ditch energy dissipater and cover plate energy dissipater is compared by means of physical model experiments.Through analyzing energy dissipation characteristics and comparing those parameters,for instance velocity distribution, remaining energy and water surface fluctuations, the results indicate that the energy dissipation effect of open ditch energy dissipater is superior to the cover plate energy dissipater under the same condition.The open ditch energy dissipater structure is simple and it is not popular in current China. It is recommended to strengthen its further research and application. References | Related Articles | Metrics

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Influence of Vegetation Characteristics on Velocity Distributionof Compound Channel LUO Xian,FANG Chun-yan,SHAN Yu-qi,LIU Chao 2010, 29(3): 466-469.  Abstract ( )   PDF (1244KB) ( )   The influence of vegetation density and vegetation height at different beaches on the velocity distribution in compound channels is discussed through the flume experiment. ADV is used to measure the instantaneous velocity at different vertical line and different measuring points; and bamboo sticks are chosen instead of arbores to participate in the simulation. The experiment results indicate that the velocity distribution follows a logarithmic distribution for non-vegetated floodplain, and obey S-shaped distribution for vegetated floodplain. The S-shaped distribution divides the flow into three regions. The range of every region is related to the flow depth, lateral location and vegetation character istics, such as vegetation density and height. For different density of vegetation, the S-shaped distribution is different. Meanwhile, it is found that the velocity in the main channel increases and that in the floodplain decreases after the floodplain is vegetated. Furthermore, the influences of vegetation density on local velocity distribution are distinctive for the same types of vege tation. References | Related Articles | Metrics

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Optimization of Positioning Export Containers in Yard WEI Jia-jun 2010, 29(3): 470-473.  Abstract ( )   PDF (603KB) ( )   Allocating conlahers in yard is a key process for each export contaher in yard managament,which is essential to shorten conlainer-ship's turnaround time in port and to enhance the loading performance of container ports. A heuristic algorithm is put forward to optimize the yard position of export containers. Simulation experiments show that this heuristic algorithm can improve the loading efficiency of contaher port, and keep the loading quality acceptable at the same time References | Related Articles | Metrics

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Ship Investment Decision Based on Compound Real Option LV Jing,GONG Xiao-xing,YANG Lin-da 2010, 29(3): 474-479.  Abstract ( )   PDF (1738KB) ( )   The ship investment decisions with the characteristics of compound real options are investigated. Binary tree model is established, and Crystal Ball software is used to simulate the fluctuation ratio of shipping market through Monte Carlo method, and then the project of ship investiment is evaluated. The emprical results indicate the ship investment projects with multiple choices have much more value than those ship investment projects with single option do. References | Related Articles | Metrics

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Study onCombustion Characteristics of Partial Premixed Charge Compression Ignition-Direct Injection Engine Fueled with Dimethyl Ether LI Wei,ZHOU Long-bao,WANG Ying,MA Jun 2010, 29(3): 480-483.  Abstract ( )   PDF (699KB) ( )   Experimental investigation on the combustion characteristics of PCCI-DI combustion by the partial pilot DME from the intake pipe is carried out.Results indicate that the engine has lower peak cylinder pressure and lesser rise rate of pressure.PCCI-DI DME engine also shows an obvious two-stage heat-release characteristic.Compared with HCCI DME engine, the peak values of two heat-release stages are reduced: the position of the first peak has almost no change and the position of the second peak shifts to the position near after TDC. References | Related Articles | Metrics

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Analysis on Total Compressing Power in Two-Stage Turbocharging System HE Yi-tuan 2010, 29(3): 484-487.  Abstract ( )   PDF (529KB) ( )   To discuss the total compressing power of the single stage turbocharing system and the two-stage turbocharging system, the compressing processes of two systems are theoretically analyzed on the P-V diagram. The test is carried on a special two-stage turbocharging test bench, and the test result of the two-stage system is compared with that of the single stage system. The results indicate that, the total compression power of the two-stage turbocharging system maybe larger than that of the single stage system because of the pressure losses in the intercooler and pipes. Only all the conditions are satisfied,that means the total pressure ratio is higher enough, the temperature drop is bigger enough, the pressure losses of intercooler are less enough, and both the high and low stage compressors operate with high efficiency, the two-stage turbocharging system can be advantageous. References | Related Articles | Metrics

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Skin Color Division Base on Modified YCrCb Color Space CAO Jian-qiu,WANG Hua-qing,LAN Zhang-li 2010, 29(3): 488-492.  Abstract ( )   PDF (948KB) ( )   Face recognition is a crossed subject of computer vision, pattern identification, biology character identification, and digital image processing. Skin color division is one of the most important steps of face recognition. Aiming at the current condition that the skin color division based on YCrCb color space can't distinguish the face accurately in the strong light, a modified division method of YCrCb color space is put forward to improve the adaptability and accuracy of YCrCb in strong light. The experiment verifies the conclusion that this new method can reduce the influence of light luminance on the human face segmentation operation, therefore it will be more accurate to find the face region and the error ratio is low. References | Related Articles | Metrics

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Comparative Study of Metal Re-crystallization Microstructure by Simulation and Experiment ZHANG Ji-xiang,WEN Hui,LIU Yun-teng 2010, 29(3): 493-496.  Abstract ( )   PDF (992KB) ( )   The simulation of metal re-crystallization by computer could simulate the details of microstructure evolution which can't be observed in experiment. Meanwhile, the quantitative characteristic parameters are obtained, and the properties of material after annealing are also forecasted, which can guide the heat treatment process design. A new MC Potts simulation model is constructed, and is used to simulate the static re-crystallization behaviours of 1060 aluminum alloy. With the simulation, an experimental study is also carried out for comparison. The results show that 1060 aluminum alloy presents significant re-crystallization characteristics, and an approxim ately isometric crystal organization is obtained in the re-crystallization experiment. The simulation results of re-crystallization nucleation location and microstructure morphology got by this model are consistent with experimental results, and the evolution process of crystal structure is also consistent with experimental results generally; however, the simulated isometric crystal organization is not exactly consistent with approximately isom etric crystal organization by experiment, and the velocity of re-crystallization by simulation is also lower than that by experiment References | Related Articles | Metrics