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31 July 2017, Volume 36 Issue 7 Previous Issue    Next Issue
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Bridge & Tunnel Engineering
Highway & Railway Engineering
Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment
Traffic & Transportation Engineering
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Bridge & Tunnel Engineering

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Redundancy Analysis on Long-Span Suspension Bridge Based on Sling Importance ZHU Jinsong1, 2, WANG Yang1 2017, 36(7): 1-7.  DOI: 10.3969/j.issn.1674-0696.2017.07.01 Abstract ( )   PDF (2044KB) ( )   To analyze the impact of the failure of different slings on bridge redundancy in the operation of a suspension bridge, a long-span suspension bridge being in construction was taken as example. By use of the variation of strain energy of the whole structure before and after the failure of slings of the suspension bridge, the importance coefficients of slings were determined. According to the importance coefficient, the failure slings were combined, and the failure condition of components were determined. And then, the quantitative calculation of the suspension bridge redundancy under the most adverse damage conditions was carried out. Combined with the stress increment of the damaged structure, the redundancy analysis method of a suspension bridge based on the sling importance coefficient was put forward. The results show that: when the sling failure is closer to the mid-span, its effect on long-span suspension redundancy is bigger. The failure condition of sling combinations with the bigger important coefficients is simulated. It is founded that when the redundancy is less than 0.201, the stress response of a long-span suspension bridge is enormous; and the bridge has a trend of total structural collapse, which is no longer available to bear the load. References | Related Articles | Metrics

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Finite Element Simulation Method of Steel-Concrete Composite Structure Considering the Interface Effect FAN Liang1, LI Xiao1, HE Jun2 2017, 36(7): 8-14.  DOI: 10.3969/j.issn.1674-0696.2017.07.02 Abstract ( )   Due to the complexity of a shear transfer problem of the contract interface between steel and concrete, there are various finite element simulation methods on the steel-concrete composite structure currently. However, most of the methods are either too complicated for technical problems or too experiential which depends on many test results to determine the parameters. Therefore, considering the idea of combination of practicality and accuracy, a method using specific hyper elastic virtual interface element was proposed to simulate the steel-concrete composite structure. And it also suggested the concrete plastic damage model can be adopted. The proposed method was applied to the numerical simulation of the mechanical property and interfacial shear force in the whole development process of composite structure shear connector’s push-out tests. The results show that the proposed method is feasible and reliable, which is applicable to the FE simulation of the steel-concrete composite structure considering the interfacial bond slip effect. References | Related Articles | Metrics

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Derivation and Solution of Vibration Differential Equation of the Curved Beam with Eccentric Reinforce HE Wenzheng1, CHEN Chen2, LI Pengcheng3, WEN Jingzhou4 2017, 36(7): 15-20.  DOI: 10.3969/j.issn.1674-0696.2017.07.03 Abstract ( )   PDF (1475KB) ( )   In order to study the influence of tendon eccentricity and radius on the vibration characteristics of the curved beam, the differential equation of the vibration of the prestressed curved beam considering the influence of initial curvature on vibration was derived by analyzing the micro section of the curved beam under the condition of free vibration. Then the theoretic calculation formula of the first order natural frequency vibration of the eccentric reinforcement simply supported curved beam was deduced by solving the equation. Finally, the correctness of the proposed theoretic formula was verified by the case study. References | Related Articles | Metrics

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Deformation and Stability of Loess Tunnel FENG Xing1, YAO Yangping2, HUO Haifeng1 2017, 36(7): 21-29.  DOI: 10.3969/j.issn.1674-0696.2017.07.04 Abstract ( )   PDF (3691KB) ( )   The stress deformation and stability analysis of the loess tunnel engineering was taken as the study objective. Firstly, on the basis of SMP criterion considering the cohesion value c, the original UH model was improved and UH model considering c value was established, which made UH model could analyze the tunnel excavation problems. Secondly, the semi-implicit return mapping algorithm was adopted to update the stress, and Newton-Raphson algorithm was adopted to solve the nonlinear problems. The finite element program of UH model considering c value was compiled, and the initial over-consolidated ratio OCR as one parameter was also introduced into the finite element program. Finally, the three dimensional finite element analysis of an unlined loess tunnel was performed. The displacement of the clay around the tunnel calculated by the original UH model, the UH model considering c value and Mohr-Coulomb model were compared. And the UH model considering c value was used to carry out the calculation analysis of tunnel, whose rationality was declared. Furthermore, the displacement variation law of the clay around the tunnel was attained. The stress-strain law of the clay around the tunnel was studied by using the UH model considering c value. In addition, the security and stability of tunnel was analyzed by using the strength reduction FEM, and the relationship between over-consolidated ratio and security-stability was studied. References | Related Articles | Metrics

Highway & Railway Engineering

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Performance Evaluation of Non-viscous Wheel Modified Hard Emulsion Asphalt ZHAO Yang1, ZHOU Qiwei2, WANG Qingzhen3, WANG Min2, LIU Yuheng4 2017, 36(7): 30-32.  DOI: 10.3969/j.issn.1674-0696.2017.07.05 Abstract ( )   PDF (1595KB) ( )   Aiming at the defects of sticking wheel and insufficient adhesion of the traditional emulsified asphalt in construction, the asphalt 30# with high viscosity and softening point was used, and the modified hard emulsified asphalt with the function of non-viscous wheel was successfully developed. The emulsified asphalt adhesion test was proposed from a qualitative and quantitative angle, which determined the adhesion rate as the control index of sticking wheel. The test shows that the non-viscous wheel modified hard emulsion asphalt has a good performance in the reduction of wheel adhesion, and its inter-layer cohesiveness is better than that of ordinary emulsion asphalt and SBR modified emulsion asphalt. The proposed asphalt has a practical engineering application value. References | Related Articles | Metrics

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Rutting Prediction Model of Asphalt Pavement Based on Acceleration Loading Tests by Tandem Axles HU Peng, ZHANG Xiaoning 2017, 36(7): 33-38.  DOI: 10.3969/j.issn.1674-0696.2017.07.06 Abstract ( )   PDF (2401KB) ( )   In order to study the rutting change law of asphalt pavement under heavy load traffic, the test road of asphalt concrete surface layer and cement stabilized macadam base was paved indoor. Under two different conditions, that is the indoor common temperature loading and the conolition that the pavement was heated to 42℃, the acceleration and loading equipments with independent research and development were used in biaxial acceleration loading test. During the experiments, the temperature, the rutting and the strain were monitored. According to the variation law of rutting, the asphalt concrete pavement rutting prediction model was established under the loading condition of bi-axles and bi-wheels with 160 kN axle load. The results show that: under the loading condition of bi-axles and bi-wheels, the wheel depth is greater than that of single axle loading rutting with the same loading times, and the proposed model is more suitable for the current road traffic condition. The correctness of the proposed model is verified by comparative analysis. References | Related Articles | Metrics

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Performance Evaluation Mechanism of Pavement Crack Recognition Algorithms Based on PR Curve with Tolerance PENG Bo1, JI Ran2 2017, 36(7): 39-45.  DOI: 10.3969/j.issn.1674-0696.2017.07.07 Abstract ( )   PDF (2735KB) ( )   In order to assess the performance of pavement crack detection algorithm objectively and reasonably, an algorithm performance evaluation mechanism based on PR curve with tolerance was proposed. Firstly, a benchmark library of pavement crack images was built to provide the unified and standard test images for evaluating crack detection algorithm performance. Secondly, calculation methods of precision ratio, recall ratio and F1 value considering tolerance were put forward as measurement indicators of algorithm performance. Then, a PR curve based on evaluation method for pavement crack detection algorithms was proposed. At last, two crack detection algorithms were evaluated and analyzed as examples by using PR curve. Results show that, the proposed PR curve evaluation mechanism establishes the unified benchmark test images, measurement indicators and evaluation method, which can assess performance (including precision ratio, recall ratio, F1 values and algorithm stability) of crack detection algorithms without or with 1 or more parameters. It is helpful for algorithm performance evaluation and improvement. References | Related Articles | Metrics

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Numerical Analysis on Uneven Settlement of Dazhun Railway Filling Subgrade SUN Shuwei,YAN Yatao, SUN Yugui, ZHAO Fu 2017, 36(7): 46-50.  DOI: 10.3969/j.issn.1674-0696.2017.07.08 Abstract ( )   PDF (2620KB) ( )   Firstly, K36+480 filling subgrade was selected; secondly, the influence of train load, compaction coefficient of filling layer, the elastic modulus of filling layer or substratum on the uneven settlement was simulated and analyzed by FLAC 3D software and the simplified three-dimensional model. The results show that: the settlement difference between the center and the edge of the subgrade is increased under train load, which causes uneven subgrade surface and even uneven settlement; the settlement trends of the subgrade with different compaction coefficients are approximately similar, and with the increase of compaction coefficients, the stability and robustness of the subgrade also increases; the difference of elastic modulus of filling layer or substratum (loess) causes the uneven settlement, when it reaches a certain value, it has a little influence on the subgrade settlement. References | Related Articles | Metrics

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Ground Surface Settlement Incurred by Excavation of Foundation Pit in Watery Filling Area JIN Xiaoguang1, 2, HOU Xiaohe1, 2, SUN Zhigang1, 2, ZHANG Haoling1, 2 2017, 36(7): 51-57.  DOI: 10.3969/j.issn.1674-0696.2017.07.09 Abstract ( )   PDF (2333KB) ( )   The estimation methods of the ground surface settlement incurred by the foundation pit excavation of filling area influenced by underground water seepage were discussed. The computation formula of the ground surface settlement caused by the foundation pit excavation was also deduced. Combining with the excavation project case of deep foundation pit at rail transit interval in watery backfilling area, both theoretical analysis and simulation study of the ground surface settlement around the foundation pit were carried out. The results show that underground water seepage is one of the important reasons for the ground surface settlement around the foundation pit. With good practicability and reliability, the proposed method is useful in estimating the ground surface settlement in similar geological environment. References | Related Articles | Metrics

Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment

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Fractal Characteristics of Longitudinal Section of River Bed NI Zhihui1, 2, WANG Wei1, WU Lichun3 2017, 36(7): 58-65.  DOI: 10.3969/j.issn.1674-0696.2017.07.10 Abstract ( )   PDF (4585KB) ( )   Taking Shuifu to Zhutuo section in mainstream of the Yangtze River as the research object, an unsteady and fractal mathematics model with one-dimension was established. The studied section was divided into 3 segments, and the confluence of Minjiang River and Tuojiang River was taken as a demarcation. The fractal dimension of longitudinal section in river profile was calculated. The research indicates that: the fractal dimension of longitudinal section has two order fractal characteristics, and the overall fractal dimension is smaller than that of the piecewise. The value of overall fractal dimension is not equal to the arithmetic mean of fractal dimension of various sections. Fractal dimension of longitudinal section decreases as the flow increases. The longitudinal slope in various sections of river course is changing with the fractal dimension of longitudinal section, whose morphology is similar to the wave shape. References | Related Articles | Metrics

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Formulas for Estimating Size-Dependent Normal Contact Resistance of 3D Bonded Spheres LIU Fang1, 2, 3, ZHOU Xiangnan 2, 3, JIANG Mingjing1, 2, 3 2017, 36(7): 66-72.  DOI: 10.3969/j.issn.1674-0696.2017.07.11 Abstract ( )   PDF (3935KB) ( )   The presence of inter-particle bonds leads to the unique macroscopic deformation and strength characteristics of natural structural soils. In order to study 3D cement particle contact failure regularity and size effect under the normal loading conditions, the contact mechanics test of ideal spherical particle cementation was simulated by finite element method. The results of the finite element simulation and those of discrete element simulation were compared. The finite element method was used to simulate normal contact response of two spheres sandwiching cementation in order to reveal the size effect on normal resistance of bonded spheres. The simulation results of finite element were compared with those of discrete element. The rule of compression/tension resistance of the bonded spheres was analyzed under different values of two dimensionless geometric parameters of the bond, i.e., diameter ratio and thickness-to-width ratio of the bond. Quantitative relationships between contact strength and cement size parameters were obtained. The results show that the compressive resistance of the bonded spheres is highly affected by the diameter ratio and the thickness-to-width ratio of the cementaneous material, and the thickness-to-width ratio plays a dominant role. The compressive resistance of the bonded spheres significantly decreases as the thickness-to-width ratio of the bond increases, while the size effect of the cement particle tensile strength is not significant. References | Related Articles | Metrics

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Treatment of Key Problems in Shipping Development of the South-to-North Water Transfer Project TAN Bin 2017, 36(7): 73-76.  DOI: 10.3969/j.issn.1674-0696.2017.07.12 Abstract ( )   PDF (1335KB) ( )   According to the present situation of the South-to-North Water Transfer Project, the treatment of key problems of shipping development of the South-to-North Water Transfer Project were discussed: ①How to ensure the adequate water supply for the development of shipping and the effective supplement of the Yangtze River water from the South-to-North Water Transfer Project was a problem that must be solved in the South-to-North Water Transfer Project; ②The South-to-North Water Transfer Project adopted the standard ship type, which could enhance the advantage of products and improve the ability of massive production and management. The above measure could not only save costs massively, but also cover the relative pollution produced by the ship and crew completely into the controllable range, which effectively guaranteed the quality of the transferred water had no change; ③The middle route of the South-to-North Water Transfer Project and the eastern route must pass through the Yellow River, and how to suit the complicated and changeable situation of the Yellow River was a problem that must be faced. References | Related Articles | Metrics

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Fractal Geometry Analysis on Complexity of Limestone Fracture Mesoscale LIU Chuanxiao1, WANG Long2, ZHANG Xiaolei1, LI Maotong1, ZHOU Tong1 2017, 36(7): 77-82.  DOI: 10.3969/j.issn.1674-0696.2017.07.13 Abstract ( )   PDF (2496KB) ( )   The stress-strain time series and rock damage experimental fractures were obtained by laboratory uni-axial and tri-axial compressing experiments on limestone. The experimental fractures with the compressive failure of different confining pressures were analyzed by scanning electron microscope imaging experiment. Fractal dimensions in mesoscale space of limestone fractures were calculated to trace the damage feature quantitatively. The general rule that when the confining pressure increases (< 20 MPa), the compressive failure process inclines to be complicated and the fractal dimensions of limestone factures increase was obtained. When the confining pressure increased to about 2/3 uni-axial compressive strength of rock, latter compressing process may be controlled by new radial damage caused by high surrounding pressure, which resulted in that the final failure cause tended to be simple and the fractal dimensions of rock damage factures tended to be the minimum. The fractal dimension reduction index was introduced into the basic relation of continuum damage mechanics, and a fractal damage statistical model describing mesoscale failure mechanism of limestone was established. Comparing with the stress-strain test results, it is indicated that the fractal damage theory model is fitted with the experimental relation curve and can ideally reflect the strain softening feature of limestone tri-axial compression test. The proposed model is a valuable discussion for mesoscale failure mechanism of the damaged rock. References | Related Articles | Metrics

Traffic & Transportation Engineering

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Fluctuation Analysis on Road Traffic State Based on Fuzzy Information Granulation and Support Vector Machine LU Baichuan1, 2, LI Xiaolu1, GUO Guilin1, HUANG Lili1 2017, 36(7): 83-89.  DOI: 10.3969/j.issn.1674-0696.2017.07.14 Abstract ( )   PDF (3256KB) ( )   In order to analyze the range of traffic state fluctuation, a combined modeling method of forecasting the range of traffic state fluctuation based on fuzzy information granulation and support vector machine was put forward. The fluctuation characteristics of road traffic state and the selection principles of traffic parameters were analyzed on the basis of fuzzy theory and time series prediction. The sample data were fuzzed by 15 min time window through the fuzzy information granules, and three sets of time series, including Low, R and Up, were obtained. The support vector machine was used to forecast each set of time series, and the traffic state fluctuation range and variation tendency were obtained. In case studies, in the premise of verification data acquisition segment with similar attributes, the proposed model was used to analyze the fluctuation of traffic state in morning, evening peak periods and peace period, whose results were of high accuracy and could effectively predict the fluctuation of traffic state. References | Related Articles | Metrics

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Optimization of Time Setting of Jingtong Expressway Bus Lanes CHEN Yanyan1, ZHAO Jin1, LAI Jianhui1, XIONG Jie1, HUANG Linjun2 2017, 36(7): 90-95.  DOI: 10.3969/j.issn.1674-0696.2017.07.15 Abstract ( )   PDF (1408KB) ( )   Based on the characteristics of passenger flow in mass public transportation IC card (Integrated Circuit Card) data analysis, the current situation that the time setting of Jingtong expressway bus lanes did not fully meet the peak demand of bus passenger flow was discovered. According to this, the total travel time index was proposed and the Jingtong expressway traffic situation was evaluated. Meanwhile, the scheme with the extension of bus lane setting time was simulated and evaluated. The research shows that: with the time increase of bus lane, the overall passenger traffic efficiency is increased, and the best time for extension is 1 hour. Finally, according to the research results, several principles and methods for bus lane time setting are put forward. References | Related Articles | Metrics

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Experimental Evaluation of Anti-collision Performance of Reconstruction Scheme of Old Column of Highway LI Xia, YANG Huaijun, CUI Hongjun, TIAN Yuan, ZHAO Zhiqiang 2017, 36(7): 96-100.  DOI: 10.3969/j.issn.1674-0696.2017.07.16 Abstract ( )   PDF (1462KB) ( )   The crashworthiness of guardrail post in old standard can not satisfy the current specification requirements in the process of expansion. From the perspective of improving the column bending and tension performance, the upgrade and reconstruction design scheme of column in old standard was put forward. In the proposed scheme, the soil underground and inside the column was removed and the reinforced concrete was filled. Through the mechanics calculation, the force characteristics of column bending and pullout were analyzed, and the reasonable depth and height of the concrete filled inside the column were also determined. Finally, the bending static load, bending quasi-dynamic load, pendulum impact test and pullout quasi-dynamic load experiment of the old specification columns, the current specification columns and the upgraded columns were carried out and compared. The research indicates that the crashworthiness of column in old specification upgraded and reconstructed by the proposed scheme can meet the design requirements of the current specification. References | Related Articles | Metrics

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Improved Interpretive Structural Model of Influencing Factors of Resident Travel Cost ZHANG Xiqiao, YUAN Yalong, SUN Zhichao 2017, 36(7): 101-105.  DOI: 10.3969/j.issn.1674-0696.2017.07.17 Abstract ( )   PDF (1203KB) ( )   Travel cost as an economic lever is used to adjust the travel structure of residents by traffic administrator, and it plays an important role in the traffic supply and demand management system. From the point view of system science thinking and theory, the primary and secondary relationship as well as the hierarchy of the influencing factors was obtained by the improved interpretative structural model, on the basis of defining ten factors which affected residents’ travel cost. With the analysis results of the improved interpretative structural model, the influencing factors of residents’ travel cost could be divided into two kinds: the quantifiable hard factors and the psychological perception soft factors, which improved the understanding of the relationship among the influencing factors of residents’ travel cost. Finally, according to the directional graph of hierarchical relations among the factors, some suggestions were given to adjust residents’ travel cost and optimize the travel structure. References | Related Articles | Metrics

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Establishment of Accident Severity Prediction Model of Two-Lane Highway on Qinghai-Tibet Plateau SUN Xiaoduan, HOU Yangyang, HE Yulong, FENG Bingbing 2017, 36(7): 106-110.  DOI: 10.3969/j.issn.1674-0696.2017.07.18 Abstract ( )   PDF (1324KB) ( )   Based on the analysis of traffic accident data of Qinghai-Tibetan plateau, it is found that most of the traffic accidents are of high casualties, which means the proportion of accidents with deaths and injuries is relatively larger. The cumulative Logistic regression was used to research the factors which affected the severity of traffic accidents in plateau area. The collected accident severity was selected as the dependent variable. The altitude of the environment, the oxygen content, the weather, the linear and environment of the accident site, the type of the vehicle, the traffic volume, carts ratio, the speed difference between cart and car were selected as independent variables. Therefore, the cumulative Logistic regression model was established. The results show that five independent variables including altitude, carts ratio, the vehicle type and the speed difference between the cart and the car are significantly correlated with the severity of accident. This prediction model can provide theoretical basis for the related highway management departments to make safety measures. References | Related Articles | Metrics

Vehicle &Electromechanical Engineering

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Fitting and Verification of Utility Model of Mandatory and Semi-mandatory Speed Humps LIN Peiqun, LEI Yongwei, GU Yumu 2017, 36(7): 111-116.  DOI: 10.3969/j.issn.1674-0696.2017.07.19 Abstract ( )   PDF (2717KB) ( )   Observation and quantitative analysis on the vehicles’ speed decelerating by mandatory and semi-mandatory speed humps were carried out, and a quadratic polynomial model of dual carriageway rubber speed humps speed and distance was established. The exponential function model of two-way eight-lane semi-mandatory speed humps speed and distance was also established. The decelerating utility of speed control facilities was described. The reliability and validity of the proposed model were checked. Results show that the studied mandatory and semi-mandatory speed humps are suitable for the same type of roads and the same type of deceleration zone settings. References | Related Articles | Metrics

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Control Strategy and Simulation of Bionic Elbow Joint Compoundly Driven by SMA-Motor LUO Tianhong, GUO Yuan, LIANG Shuang, LI Huilan, LI Qiaoyi 2017, 36(7): 117-122.  DOI: 10.3969/j.issn.1674-0696.2017.07.20 Abstract ( )   PDF (2580KB) ( )   For the bionic elbow joint compoundly driven by SMA-motor with the characteristics of nonlinear, time varying and temperature hysteretic, the fuzzy control algorithm based on double inputs and four outputs was proposed and the fuzzy PID adaptive control model was established. The motion states of the composite driven bionic elbow were solved in the step response and the theoretical trajectory, and then the position and the angular velocity tracking graphs of the rotating and pitching motion of the elbow joint were obtained. Experimental results show that the design of dual-input and quadri-output adaptive fuzzy PID control has the characteristics of small overshoot, high system robustness and fast response speed, which can achieve the accurate position control of bionic elbow compoundly driven by SMA-motor. References | Related Articles | Metrics