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12 June 2018, Volume 37 Issue 06 Previous Issue    Next Issue
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Bridge & Tunnel Engineering
Highway & Railway Engineering
Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment
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Bridge & Tunnel Engineering

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Study on Temperature Field of Massive Concrete with Pipe Cooling in Initial Stage of Hydration Heat LI Zhida，SUN Xutao 2018, 37(06): 1-7.  DOI: 10.3969/j.issn.1674-0696.2018.06.01 Abstract ( )   PDF (1035KB) ( )   According to the equivalent heat conduction equation of pipe cooling in mass concrete，a three-dimensional finite element real model of the bearing platform was built by the finite element analysis software Midas/Civil，based on the construction of the #22 pilecap of Wuhan Fuhe Bridge.The simulation of the temperature field in #22 pilecap was conducted，and the temperature of the concrete was monitored.After comparing the finite element calculation results and the measured data，it was showed that the two results were in good agreement.This shows that the established finite element model is capable of simulating the variation characteristics of the temperature filed in mass concrete in the initial stage of hydration heat.The finite element calculation results reveal that the distribution of tensile stress on the surface of the pilecap was improved after strengthening the insulation of the pilecap surfaces.The risk of cracking was effectively reduced.By analyzing the impacts of inlet temperature of pipe cooling according to thefinite element model ，it can be proven that although the drop in inlet temperature can effectively reduce the maximum temperature of interior of concrete and can enable the pilecap to reach its maximum temperature in a short time before beginning the cooling down process. There are also some negative effects.It is desirable to make corresponding adjustments of the inlet temperature of cooling pipe by the maximum temperature in interior of the pilecap.In actual engineering，it is best to make corresponding adjustments to the inlet temperature of pipe cooling according to the maximum temperature in the interior of the pilecap. References | Related Articles | Metrics

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Characteristics of Defects in Expressway Plate Bridges Based on Maintenance Data XIE Faxiang，DING Pengfei，CHEN Xin，ZHAO Wei，JI Bohai 2018, 37(06): 8-15.  DOI: 10.3969/j.issn.1674-0696.2018.06.02 Abstract ( )   PDF (552KB) ( )   An analysis was made on the maintenance data from the bridge maintenance system of Jiangsu Communication Holding Group (JCHG) for a highway which had been in operation for 15 years. The main faults and defects and their prime characteristics were determined. The identification and distillation of defects and fault attributes were realized by using the Microsoft Visual Basic for application (VBA) program. A new defect and fault characteristic database was built, and the overall defect and fault characteristics of the plate girder bridge, different span plate girder bridge defect and fault characteristics, and board girder bridge defect and fault characteristics developed over time were statistically analyzed. The results show that the crack in the beam body was the most important disease form, followed by the bearing disease and abutment damage. The lateral transverse cracks of 8, 10, and 13 m beams are most concentrated, while the vertical cracks in the web of the 16 m beams and the transverse cracks in the wing protrude of the 20 m beams are prominent. The main diseases of the bearing increase linearly with the span, and the cracks on the piers and terraces decrease linearly with the span. The cracks of the plate-girder bridge generally increase with the year, and the transverse cracks on floor plates, the vertical cracks on web plates , and the transverse cracks on wing plates tend to ease after 11 years of opening to traffic. The main diseases of the bearing increased rapidly with the year, especially after 11 years of opening to traffic. References | Related Articles | Metrics

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Study on Critical Thickness Ratio of Thinwalled Hollow Piers with Constant Cross Sections ZHOU Shuixing，YAN Chengjun 2018, 37(06): 16-20.  DOI: 10.3969/j.issn.1674-0696.2018.06.03 Abstract ( )   PDF (359KB) ( )   Based on the condition that the central pressure bar had the same stabilizing coefficient，the calculation formula of the critical load of the central pressure bar under the combined action of the self-weight and the concentrated loads on top of the rod was deduced.Regarding the thin-walled hollow pier as a structure made of sheet components，in accordance with the failure form of the thin-walled hollow pier，where overall instability initially occurs，by setting the control condition that the overall stability stress of the piers was less than the critical stress of the slab the critical formula of thickness ratio (critical thickness) was deduced，and the result of the formula was verified using the finite element model.The results show that the limit thickness can be calculated using the formula in this paper，and that the calculation accuracy can meet engineering requirements. References | Related Articles | Metrics

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Analysis of Influence of Surface Load on Shallow Buried and Asymmetric Neighborhood Tunnels ZHANG Xuefu1，ZHOU Yuanjiang2，ZHOU Yuanfu1，ZHOU Jie1 2018, 37(06): 21-27.  DOI: 10.3969/j.issn.1674-0696.2018.06.04 Abstract ( )   PDF (545KB) ( )   In order to obtain the specific characteristics of subsidence，crown settlement，and support stress of shallow buried and asymmetrical neighborhood tunnels under surface loads in the process of construction，two processes of construction based on the Chongqing Yuzhong tunnel project were analyzed using a 2D numerical simulation method when the surface load was distributed over the small tunnel，the large tunnel，or two tunnels.The research results show that when the small tunnel is constructed with the unilateral pilot tunnel method and the large tunnel is constructed with the ring cut method，the larger the total surface load is，the larger the subsidence of ground is.The surface load affects the value of final subsidence and shape of the curve of subsidence.The construction procedure of the tunnel has no effect on the law of crown settlement.The excavation of the following tunnel close to the antecedence tunnel has great influence on the supporting stress of antecedence tunnel.The results can provide theoretical support and scientific guidance to similar construction projects. References | Related Articles | Metrics

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NewType of Similar Model Experiment System for EPB Soil Conditioning and Its Function Verification YANG Zhenxing1，2，CHEN Kui1，2，CHANG Jiadong3，ZHOU Jianjun1，2，LI Wei4，ZHANG Hepei1，2 2018, 37(06): 28-35.  DOI: 10.3969/j.issn.1674-0696.2018.06.05 Abstract ( )   PDF (997KB) ( )   Based on a summary and analysis of the research of soil conditioning at home and abroad，the limitations of various current indoor experiment methods were pointed，and a newly developed similar model experiment system for soil conditioning called the EPB Soil Conditioning Experimental System was introduced.This system gathers the functions of foam generating，shield tunneling，screw conveying，etc.to realize the following advancements and innovations：Enabling strata remodeling，simulating the process of shield tunneling，realizing soil cutting and soil residue mixing; Adding a foam modifier according to the design ratio of the soil warehouse，mixing it，and determining the effects of soil conditioning on boring parameters; Simulating four states of EPB shield tunneling：the open style shield，semi-earth pressure balance shield，earth pressure balance shield，and overvoltage drilling models; Simulating the processes of screw conveyor soil output and soil plugging effect realization.At last，functional tests such as shield boring simulation and soil conditioning tests were carried out in order to verify the accuracy and reliability of the system.The development of this experimental system provides a new method for researching the impact assessment of the ratio of soil improvement and optimization.It simulates the excavation process of the large diameter EPB shield，particularly under complex geological conditions，obtains the optimal construction parameters of the EPB shield，and guides construction. References | Related Articles | Metrics

Highway & Railway Engineering

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Foaming Mechanism of Asphalt Binders Foamed and Evaluating Index of Foaming Effect of Foamed Binders HUANG Weirong1，REN Haisheng2 2018, 37(06): 36-41.  DOI: 10.3969/j.issn.1674-0696.2018.06.06 Abstract ( )   PDF (907KB) ( )   The whole process of asphalt creation，from foaming to de-foaming and maintaining a stable state，is introduced from a micro view and its foaming mechanism is analyzed.The conclusion is drawn that the foaming process of asphalt is the interaction between asphalt film surface tension and interior vapor pressure.The disadvantages of applying existing evaluation indexes to foamed asphalt warm mixing technique were analyzed from three aspects of theory，testing，and application to foamed asphalt warm mixing technique of the existing evaluation indexes of foamed asphalt.Finally，three new evaluation indexes，these being foam diameter，size distribution，and de-foaming rate，were proposed based on use of a laser range finder and digital camera，among other equipment using a non-contact testing method.The results of the study show that the non-contact testing method combined with the new indexes can better evaluate the effect of asphalt formation. References | Related Articles | Metrics

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Research on Permeability and Road Performance of Permeable Asphalt Mixtures XU Hongyue 2018, 37(06): 42-47.  DOI: 10.3969/j.issn.1674-0696.2018.06.07 Abstract ( )   PDF (415KB) ( )   The testing methods of void ratio and the permeability coefficient of different asphalt mixtures were contrasted and analyzed.The void ratio distribution characteristics and the permeability performance of permeable asphalt mixture were tested.Such road performances as high temperature performance，low temperature performance，and water stability of the mixture were studied and investigated.The results show that the effective void ratio percentage of PAC-13 permeable asphalt mixture is obviously greater than that of PAC-10.The permeable coefficient of permeable asphalt mixture and effective void ratio have a fine exponent relationship，and no correlation existed between the void ratio and height.Application of an effective void ratio index can better reflect the permeability of permeable asphalt.With roughening，the grading of high temperature performance of the same type of permeable asphalt mixture increases and its water stability and low temperature performance is reduced.Relatively speaking，PCA-10 permeable asphalt mixture，compared with PAC-13，has better water stability and low temperature performance but relatively poor high temperature performance. References | Related Articles | Metrics

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Influence Mechanism of Frost Resistance and Microstructure of Road Concrete GUO Yinchuan，ZHAI Chaowei，LI Peng，SHEN Aiqin 2018, 37(06): 48-55.  DOI: 10.3969/j.issn.1674-0696.2018.06.08 Abstract ( )   PDF (2383KB) ( )   The frost resistance of road concrete is one of the most important factors in the durability of cement pavement.In order to understand the essence of road concrete frost resistance changes in the law，the freezing regularity of road concrete under different water-cement ratios and gas contents have been explored using the quick freeze method， and the stomatal structure and pore structure of road concrete have been analyzed using a Scanning Electron Microscope- Image Pro-plus (SEM-IPP) that were invented by the research group and Mercury Injection Porosimetry (MIP)，with the results of both macro and micro tests having been analyzed.The results show：the average pore diameter and stomatal spacing decreased by 30% and 22% respectively when the water-cement ratio decreased by 0.04，meanwhile，the frost resistance of road concrete increased by 15%; the average pore diameter and stomatal spacing decreased by 44% and 51% respectively, the frost resistance of road concrete increased by 35% when increased air entraining content 1/10 000.The increase in percentage of the <50 nm holes and the decrease of the average pore diameter and stomatal spacing resulting from the decreasing water-cement ratio or increasing air entraining content improved the internal structure of the pores and pore structures and reduced fractures，large holes，and hole connectivity，thus making the internal microstructure dense，which is beneficial to the improvement of frost resistance of road concrete. References | Related Articles | Metrics

Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment

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Spatio-Temporal Evolution Process of Vegetation Coverage of Hydro-Fluctuation Belt in Three Gorges Reservoir Based on GIS-RS GUAN Dongjie1，2，QU Sijia1，YANG Shanshan1, HE Xiujuan1 2018, 37(06): 56-62.  DOI: 10.3969/j.issn.1674-0696.2018.06.09 Abstract ( )   PDF (735KB) ( )   The Fuling Hydro-Fluctuation Belt in the Three Gorges Reservoir was taken as a case study to carry out land use classification of hydro-fluctuation belts and estimate vegetation coverage of hydro-fluctuation belts based on remote sensing and geographic information systems.The CA-Markov model was used to calculate the transition probability matrix wetland use type，and at the same time the CA-Markov model was used to simulate the wetland landscape pattern of the study area in 2018，2023，2028，and 2033.The results show that for the hydro-fluctuation belt in a year or two，with this short a period，vegetation cover type will undertake relatively large changes with low stability and long-term change is stabilized，especially for the first time in 2008 after a 175m water test; For spatial pattern，terrestrial plants and wetland plants belong mostly to the category internal transfer，namely，terrestrial turned wet.The overall vegetation coverage is slightly reduced but later is basically stabilized at nearly 50% of the total vegetation in a later period of time. References | Related Articles | Metrics

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Discussion on Yield Failure of Bedding Rock Slopes ZHANG Dengxiang，TANG Chuan，TANG Qiuyuan 2018, 37(06): 63-68.  DOI: 10.3969/j.issn.1674-0696.2018.06.10 Abstract ( )   PDF (1129KB) ( )   Yield failure that occurs in bedding rock slopes is a special failure mode.At first，the mechanical mechanism of this mode of damage was explored，and the preconditions to generate this type mode of damages were obtained.Namely，in addition to the structural plane inclined slope，the steep angle of the structural plane，larger or equal to the inclined angle，and poor strength of rock body at slope foot were also determined to be factors.The slope deformation in this damage mode，stress characteristics，and specific damage processes were obtained by means of the discrete element numerical analysis method.The results show that the shear stress at the foot of the slope increases with increased depth of slope excavation，and when the shear stress did not exceed the shear capacity of rock at slope foot the slope deformation mainly occurred in the form of unloading-rebounding and the slope was in stable state.When the excavation depth caused the shear stress on the slope foot to exceed the shear capacity of the rock at the slope foot，the rock at the slope foot firstly underwent yield deformation and great displacement so as to provide space for the middle and upper rock on the slope to slide down along the surface of the slope，and the slope collapsed occurred.Numerical analysis results and theoretical analysis were well validated. References | Related Articles | Metrics

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Analysis of Ecosystem Disturbance in Economic Corridor Along Southern Silk Road Based on Land Use HAN Huiqing1，ZHANG Yingjia1，GAO Hongjuan2，LI Lin1，ZHAI Chenyu1，LI Ling1 2018, 37(06): 69-75.  DOI: 10.3969/j.issn.1674-0696.2018.06.11 Abstract ( )   PDF (1051KB) ( )   The spatial and temporal variations of ecosystem disturbance resulting from land use in the economic corridor along the Southern Silk Road using the ecosystem disturbance index based on land use data obtained from the Climate Change Initiative (CCI) project of the European Space Agency (ESA) were analysed.Results showed that ecosystem disturbance indexes in most of Malaysia，northern Indochina，and the northwest part of South Asia were relativly high，while the ecosystem disturbance indexes in most of South Asia，southern Indochina，and northeastern Malaysia were relatively low in 1992 and 2015.The ecosystem disturbance index in the economic corridor along the Southern Silk Road showed an increasing trend from 1992 to 2015.The ecosystem disturbance index in southwestern China，Brunei，the Philippines and Timor-Leste showed a decreasing trend.The decreasing of the natural regeneration type and increasing of the artificial regeneration type are main causes that result in the increasing of the ecosystem disturbance index in the economic corridor along the Southern Silk Road. References | Related Articles | Metrics

Traffic & Transportation Engineering

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Empirical Model of Road Segment Vehicle Delay Based on Numerical Distribution of Pedestrians’ Crossing CI Yusheng1，ZHENG Shuni1，ZHAO Hantao2 2018, 37(06): 76-80.  DOI: 10.3969/j.issn.1674-0696.2018.06.12 Abstract ( )   PDF (398KB) ( )   In order to accurately describe the disruption of pedestrian crossing facilities and how this affects vehicle delay at non-signalized segments of urban roads，vehicle yield modes for pedestrians and an empirical probability model were proposed，and finally a comprehensive vehicle delay model was established based on the distribution of crossing pedestrians.The results show that the distribution of crossing pedestrians has a significant influence on the selective probability of vehicle collision avoidance modes，and the vehicle delay error is in a reasonable range between the theoretical model calculation and the actual survey case.This shows that the constructed method is effective. References | Related Articles | Metrics

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Prediction Method of Dynamic Stochastic Effective Parking Space DUAN Manzhen，CHEN Guang，ZHANG Lin，MI Xueyu 2018, 37(06): 81-86.  DOI: 10.3969/j.issn.1674-0696.2018.06.13 Abstract ( )   PDF (614KB) ( )   In order to satisfy the demand for the personalized parking guidance，an effective parking space forecast method under the dynamic stochastic condition was researched.Utilizing the C-C algorithm in a nonlinear relational model，the integration process of the C-C algorithm and the Elman recursive network were researched.During the research process，the chaotic characteristics of the phase space reconstruction were verified using Small Data.A dynamic stochastic parking forecast model was built，and a model algorithm was designed.The integration algorithm was carried out by MATLAB with real data，and the results show that the predictions are fairly consistent with the actual value and the maximum relative error.The average relative error and mean absolute error are both less than the results of the forecast method based on linear assumption.This illustrates that the integration of the C-C algorithm and network technology in the dynamic stochastic parking space forecast is effective. References | Related Articles | Metrics

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Influence of Urban Road Vehiclefollowing Interference on Driver’s Attention Distribution WU Fuwei1，2，LI Li1，FU Rui1，2，WANG Chang1，2，MA Yong1 2018, 37(06): 87-91.  DOI: 10.3969/j.issn.1674-0696.2018.06.14 Abstract ( )   PDF (471KB) ( )   To obtain the driver’s attention distribution characteristic under vehicle following interference，non-contact eye tracker，millimeter-wave radar sensors were used to build experimental platform.Real driving experiments were carried out in the urban road environment to capture the driver’s eye movement data.The attention distribution characteristics and transfer rules of driverattention were also analyzed based on the Markov theory.The results show thatduring the vehicle following process in urban road environment，the experienced driver’s attention is mainly focus on the traffic target in front of him，more attention is paid to the direction where interference vehicle cut in.There is a high probability that the driver’s attention is shifted to the forward visibility after he or she observed the left or right area; The driver’s attention to the disturbing vehicle significantly higher than the target vehicle. References | Related Articles | Metrics

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Optimization of Reversing Variable Lane Signal Timing Design Based on NSGAⅡ Algorithm LIU Wei，XIE Zhongjin，CHEN Kequan 2018, 37(06): 92-97.  DOI: 10.3969/j.issn.1674-0696.2018.06.15 Abstract ( )   PDF (624KB) ( )   By taking phase effective green light time，saturation，and reverse variable lane length as constraints，a control model of double target functions as minimum delay control time at intersection and maximum traffic capacity at intersections was established.With application of the double target optimization NSGA-Ⅱ algorithm，target functions were calculated，and the solution of signal timing of relative superiority of traffic capacity was achieved so as to achieve the goal of improvement of control efficiency at intersections.Using a Chongqing intersection as an example，the NSGA-Ⅱ algorithm was used to solve the signal timing plan of the reverse variable lane.Compared with the existing signal timing plan，the optimized signal timing plan of the reverse variable lane can improve intersection capacity and reduce control delay. References | Related Articles | Metrics

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Design and Experimental Research on Movable Guardrail of Highway Central Divider CUI Hongjun1，XING Jiangke1，LI Xia1，ZHU Zhiqiang1，WU Weiwei1，YANG Huaijun2 2018, 37(06): 98-103.  DOI: 10.3969/j.issn.1674-0696.2018.06.16 Abstract ( )   PDF (2634KB) ( )   A new concrete movable guardrail was designed for the reason that ordinary movable guardrails cannot hold both strong anti-collision performance and mobility.The new guardrail has a mobile device inside it; the guardrail reinforcement，connection mode，anchorage mode and anti-overturning mode have also been designed for it.Then the finite element software was used to simulate and calculate the mobile devices and specimen of new typed concrete movable guardrail was produced and its performance was verified manually.Heavy hammer guardrail impact tests were carried out and the results show that the new concrete guardrail is able to move flexibly and its anti-collision ability meets the requirements of the highway guardrail safety performance evaluation standard. References | Related Articles | Metrics

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Discussion on Application Method of Binding and Reinforcement of Large Cylindrical Transport Objects HE Taibi1，TU Haibin1，TAN Jinhui1，WANG Shuai1，LIN Langang2，ZENG Chuanhua1 2018, 37(06): 104-109.  DOI: 10.3969/j.issn.1674-0696.2018.06.17 Abstract ( )   PDF (613KB) ( )   In order to work out a programming method regardinglarge cylindrical objects bundled reinforcing work，a specific transportation company is taken as an example，which is responsible for the transportation of the large cylindrical objects.According to the related theory of mechanical production workmanship and the elastic-plastic，the six-free degree binding and reinforcing principle was set up.Combining with the characteristics of the transport objects and the condition of using daily-used reinforcing tools，a binding and reinforcing principle was worked out，which was in the shape of the character “eight” in Chinese.According to the actual size of vehicles and transport objects，simple treatment was provided.The Solidworks software was applied to set up a three-dimensional geometric model.A variety of inertia stress and the corresponding failure mode were analyzed，which occurred with the running vehicle’s saddles and transport objects，and the lowest strength was checked such that the binding and reinforcing objects are supposed to have，and the specific type of the binding and reinforcing objects were selected.The result show that it is very effective to bind and reinforce the objects by using the method，including establishing criteria，making plans，establishing models and checking strength. References | Related Articles | Metrics

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Model of Passenger Flow Assignment in Rail Transit Network Based on Naive Bayes WENG Xiaoxiong，WANG Zhoupan，HUANG Jingxiang 2018, 37(06): 110-113.  DOI: 10.3969/j.issn.1674-0696.2018.06.18 Abstract ( )   PDF (382KB) ( )   Passenger travel time components in urban rail transit and the corresponding distribution characteristicswere fully analyzed and a model of passenger flow assignment in rail transit network based on automatic fare collection (AFC) and naive Bias classifier was proposed.Firstly，travel time parameters were collected by using AFC data and the mean and variance of each path of travel time between OD were obtained.Secondly，by taking each passenger’s AFC data as a sample and the travel time as a characteristic property，the probabilistic classification was made using a Naive Bayes classifier.Each passenger was allocated to one path of the highest riding probability.In the end，the passenger flow of each effective path between the rail transits OD was obtained.The example of the Guangzhou subway and the simulation results show that the method can predict the distribution of the passenger flows of each effective path. References | Related Articles | Metrics

Vehicle &Electromechanical Engineering

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Research on Handling Stability Response of EPS System Under Random Excitation of Road Surface LI Zhipeng，SHI Songzhuo 2018, 37(06): 114-120.  DOI: 10.3969/j.issn.1674-0696.2018.06.19 Abstract ( )   PDF (1072KB) ( )   Aiming at the status of the different input handling and stability of vehicle steering disc jitter adverse effects，EPS model combined with vehicle dynamics model of 12 degrees of freedom，while the introduction of tire model and road model of shimmy system based on the establishment of a complete simulation model of the steering system to improve the road excitation input.To eliminate the influence of road excitation input steering performance based on the purpose of the design of sliding mode controller reaching rate tracking filter based on the motor current，the adverse effects of pavement impact was weakened.The simulation model is established to analyze the vehicle stability under different road conditions.The establishment of the simulation model by Matlab/Simulink.The simulation results show that the EPS motor control system designed in this paper can effectively weaken the random road excitation on steering system performance to produce adverse effects and improve the operation stability of vehicles. References | Related Articles | Metrics

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Research on Site Selection of Electric Vehicle Charging Stations Using Analytical Hierarchy Process REN Qiliang，WU Lixia，JIN Xugang，SU Lixiao 2018, 37(06): 121-126.  DOI: 10.3969/j.issn.1674-0696.2018.06.20 Abstract ( )   PDF (945KB) ( )   The conditions of site selection of electric vehicle charging stations were defined using 6 factors，including，but not limited to，environment，electric power，planning，and land，the technical process of the preliminary site selection of charging station was given based on the entropy weight fuzzy matter element method.The precise location model of charging stations with the lowest total construction cost was established and genetic algorithm model of precise location was designed.Finally，the rationality and feasibility of the hierarchical progressive charging station location method was tested and verified by selecting 20 charging demand points generated randomly and 8 alternative sites within a 40*40 plane. References | Related Articles | Metrics