LU Xilin , CHEN Yun , MAO Yuanjun
2011, 39(7):941-948. DOI: 10.3969/j.issn.0253-374x.2011.07.001 CSTR:
Abstract:Earthquake resilient structure is a new branch of the seismic structural design.The new structural system is not only capable of preventing from the structure failure so as to protect people’s life safety during an earthquake,but also restoring immediately the structural function after an earthquake.A research was made of several kinds of resilient structures such as replaceable structure,rocking wall,rocking frame and selfcentering structure.The paper presents a summary of the recent research on different kinds of resilient structures,and also a new replaceable technology for coupled shear wall,replaceable coupling beam and replaceable shear wall toe.
LIU Zujun , GE Yaojun , YANG Yongxin
2011, 39(7):949-954. DOI: 10.3969/j.issn.0253-374x.2011.07.002 CSTR:
Abstract:The method of coupled flutter energy analysis is proposed on the basis of the incentivefeedback mechanism and the energy stability criterion for flutter is also defined.System energy change regularity of structureair system under flutter critical wind speed is analyzed according to plate wind tunnel test.The results show that the transfer channel of the energy from the vertical degree of freedom to torsional degree of freedom is built by the aerodynamic derivatives of A*1H*3,which cause a large amount of energy accumulation in the torsional degree of freedom,and ultimately beyond the energy dissipation capacity of aerodynamic damping,resulting in the loss of torsional vibration stability of the flutter instability patterns.The research finds that A*1H*3 cos θ1 has great influence on the main energy source of system torsional motion.The main energy expenditure is torsional aerodynamic damp and the expenditure of mechanical damp is less.Inertia force,elastic force and aerodynamic stiffness of torsional system are all have no energy expenditure in oneperiod.
CHEN Ming , LI Jingpei , LIANG Fayun , SHI Sanyuan
2011, 39(7):955-959. DOI: 10.3969/j.issn.0253-374x.2011.07.003 CSTR:
Abstract:Based on the loadbearing characteristic and the deformation model of rigid pile composite foundation,the calculation formula of the negative friction area on piles considering the interaction of pilesoilcushion is deduced and confirmed through a tested example.Parametric analysis shows that when the pile elastic modulu is over a certain value,the curve of nl0 tends to be stabilized.Thus,it is not necessary to make a high value of pile strength in composite foundation design.Rationally determination of the replacement rate has an important impact on developing the whole bearing capacity of composite foundation.The depth of negative friction zone will reduce when the soil modulus on the side of pile increasing and the reduction trend will become weak with the increasing of load.A comparison of the results of parametric analysis shows that the change of soil modulus on the side of pile has the greatest impact on the depth of negative friction zone,especially when the soil modulus is small,the depth changes up to 23.6%.Thus,in soft soil area where the rigid pile composite foundation treatment methods are adopted,full consideration should be taken that the soil modulu has great impact on the depth of the negative friction zone.
JIANG Mingjing , WANG Fuzhou , ZHU Hehua , XIAO Yu
2011, 39(7):960-965. DOI: 10.3969/j.issn.0253-374x.2011.07.004 CSTR:
Abstract:In order to analyze the classical and nonclassical variables of loose sand in direct shear test,numerical investigation were carried out by DEM.Classical variables include stress,strain,velocity fields,and stresspath.Nonclassical variables include averaged pure rotation rate(APR),fabric and coordination number.In the study,the changes of variables and the relationships among them were analyzed.The results show that the nonclassical variables are microscopically essence of classical variables.
ZHOU Jian , LI Fei , ZHANG Jiao , CUI Jihong
2011, 39(7):966-971. DOI: 10.3969/j.issn.0253-374x.2011.07.005 CSTR:
Abstract:A threedimension soil nails support excavation particle simulation model is established by the software of PFC3d which is based on discrete element method(DEM).The contrast of deformation and stress during excavation between PFC3d numerical model with and without soil nailing is analyzed in order to investigate laws of excavation with soil nailing and mesoscopic mechanism of soil nailing.Great difference exists in deformation mode and level between excavation with and without soil nailing because the effect of soil nailing.The deformation of wall,foundation pit and settlement of excavation with soil nailing is smaller than that without soil nailing.Especially the deformation mode of wall with soil nailing which appears a special mode with small deformation on the top and at the bottom of wall and big deformation in the middle of wall.Finally,the mesoscopic mechanism of soil nailing is analyzed.The pullout contact between soil and nailing is not only factor for the excavation support; the soil arching is the most important factor for the soil nailing wall support excavation.The mesoscopic mechanism and PFC simulation study is expected to be a new approach for soil nailing wall support excavation research.
TANG Yiqun , ZHAO Hua , WANG Yuandong , LI Renjie
2011, 39(7):972-977. DOI: 10.3969/j.issn.0253-374x.2011.07.006 CSTR:
Abstract:Based on the dynamic triaxial tests of the reinforced soft clay around the tunnel nearby the Hailun Road station of Shanghai Metro Line 4,the characteristics of strain accumulation caused by subway vibration loading are explored by taking into account the influence of confining pressure,consolidation ratio,cyclic loading amplitudes and vibration frequency,and the change law of residual strain influenced by each factor is obtained.The logarithmic function form is adopted to describe the relationship between the residual strain and the vibration number.Besides,the model parameters are determined with the regression analysis.The research results are not only of great importance to the reinforcement of the soil around subway tunnels,but also of great theoretical value and practical meaning to the longterm settlement prediction of soft clay around tunnel under subway vibration loading.
YAN Chunling , TANG Yiqun , LIU Sha
2011, 39(7):978-982. DOI: 10.3969/j.issn.0253-374x.2011.07.007 CSTR:
Abstract:Through the dynamic triaxial tests for the saturated silt soil around the tunnel of the Jing’an Temple Station,the deformation analysis is made on the saturated soft clay under the subway train loading.The results show accumulative plastic strain increases with larger amplitude of dynamic stress and less loading frequency with the same vibration times.Orthogonal design is used to arrange the experiment by taking a full consideration of the factors which have effect on the accumulative deformation,such as vibration times,the loading frequency,the amplitude of dynamic stress,and the interaction between one factor and the other.The mathematical statistics approach is established and is used to analyze the influence rate of the deformation.It also shows that main factor which affects axial deformation of subway tunnel is the dynamic stress amplitude and the interaction function on vibration frequency and vibration times can be ignored.The study offers a valuable reference to the design of subway tunnel.
MA Xianfeng , SUI Tao , SHANG Jinhua , WANG Dongdong
2011, 39(7):983-988. DOI: 10.3969/j.issn.0253-374x.2011.07.008 CSTR:
Abstract:Dot shield tunnels as a new crosssection of tunnels gradually are increasing in soft metro subway networks,but few studies have been made of their dynamic behavior under internal explosion so far.Based on dynamic finite element method,the paper presents an analysis of the dynamic behavior of dot shield tunnels under the condition of contact and noncontact explosive including 3 kinds of explosive charge,stress states of dot shield tunnels under 3 loading conditions are obtained.Analysis results show that different damages of tunnels occur under the condition of contact,and the damage increases with the increasing of the explosive charge,no damage occurs under the condition of noncontact including 10 kg explosive charge,serious damage occurs under the condition of noncontact including 50 kg and 100 kg explosive charge.The study result provides a reference for safe operation of metro subway.
SUN Qing , YANG Min , RAN Xia , Leung C F
2011, 39(7):989-993. DOI: 10.3969/j.issn.0253-374x.2011.07.009 CSTR:
Abstract:Centrifuge model tests have been conducted to study the effects of tunnellinginduced soil movements and single pile responses in both short and long terms in clay.Three tests are performed to evaluate the effects of distance between pile and tunnel on pile responses due to tunnel excavation.The results reveal that the surface settlement calculated by Gaussian curve in short term show agreement with centrifuge test.However,Gaussian curve underestimates the measured settlement in long term at the far end of the ground surface.Both maximum induced pile axial force and bending moment take place at the tunnel spring elevation.In addition,the pile responses decrease with an increase in piletotunnel distance.However,the induced surface settlement,pile bending moment and deflection continue to increase for some time after the completion of tunnel excavation.So the effects of tunnelling in long term cannot be ignored.
SHEN Biwei , DING Wenqi , PENG Yicheng , YAN Zhiguo
2011, 39(7):994-999. DOI: 10.3969/j.issn.0253-374x.2011.07.010 CSTR:
Abstract:In segmental linings with staggered joints,the bending moment near a radial joint is weaker than that in its neighbor segment because of their difference in flexural rigidity.The joint effect is mainly materialized by adjusting the ratio of bending moment near a joint to that in the segment near the joint.Since there is no general formula to calculate the moment adjustment factor ξ so far,a full scale test will be one practical approach to determine the factor ξ.Because it is too expensive to do a full scale test for every project,referring to similar projects is a common practice for determining the factor ξ,which introduces much casualness to engineering projects.In this paper,a fullscale segment joint test was carried out,changing the radial force P and axial force F on lining segments,the internal force of the structure is calculated,the relationship between adjustment factor ξ and average moment M,axial force F,and segment length L is established,some useful conclusions are drawn.
2011, 39(7):1000-1006. DOI: 10.3969/j.issn.0253-374x.2011.07.011 CSTR:
Abstract:A study was made of the relativity between objective index and space perception of eight representative streets in Shanghai with the semantic differential (SD) method for a humanized design reference.The research reveals a close relationship between the objective indexes of streets and space perception.The indexes mainly influence the perception on the characteristics,the atmosphere and the shape of the street space.Of the indexs,the street length influences the perception most;and the street winding and the continuity of street surface the next; the afforested coverage fraction the least; however,the road intersection linear density has no effect on spatial perception.Perception on the street quality,the continuity,the striking and center and so on is too complicated to explain by the objective index selected in this research.There are overlapping influence between the objective index and the perception.Besides,perception anticipated to relate with the specific objective indexes is not completely consistent with the actual situation.
SUN Jian , PAN Bin , LI Keping , ZHANG Huiling
2011, 39(7):1007-1012. DOI: 10.3969/j.issn.0253-374x.2011.07.012 CSTR:
Abstract:The typical problems of emerging methods based on detector data for measuring delay at urban signalized intersections such as input hypothesis,model establishment and faulttolerance performance were pointed out.A new method named “sampling population” which used two rows of detectors for dynamic survey of approach delay by the signal cycle at unsaturated intersections was put forward,including the process of cycle split,the arrival time of the first car and the departure time of the last car at exit detectors,the upper and lower boundary of input gap at entrance detectors,and corresponding method for approach delay measuring.Finally,two case studies were made in Shanghai (CaoanQilianshan intersection and WuningDaduhe intersection,including 37 cycles and 1 565 vehicles) to verify the accuracy of the proposed method.The results show that mean absolute error (MAE) of the measurement delay is 4.1 seconds under no detector error compared to 0.1 seconds fewer than 95% detector accuracy.The method is insensitive to the detector error,and can be used to provide the accurate,timely and reliable delay index for traffic control system.
ZHANG Huiling , LI Keping , QIAN Hongbo , LI Xin
2011, 39(7):1013-1018. DOI: 10.3969/j.issn.0253-374x.2011.07.013 CSTR:
Abstract:The paper introduces a new delay detection method based on the video double section trigger.Two virtual detectors were set to record the vehicles’ arrival and departure information.Upon the vehicles’ arrival of the intersection,the vehicles blobs were extracted to be tested whether the blobs could be matched.If the blobs could be matched for eight times successively,the new vehicle was thus detected.A real time tracking by the vehicle’s stain and meanshift algorithm would not stop until it departed,and parameters of delay were obtained.With the proposed method,over 90% of delay and more than 95% of the traffic flow precision can be detected on real time.
DU Yuchuan , ZHOU Ziyi , LI Jiang , SUN Lijun
2011, 39(7):1019-1025. DOI: 10.3969/j.issn.0253-374x.2011.07.014 CSTR:
Abstract:Identifying the “health problem” of traffic monitoring equipments is important to longterm performance of intelligent transportation system (ITS) application system.Based on statistical distribution analysis of plentiful traffic data archives,a quantitative method to seek the potential problem of traffic observations is proposed.Employing freeflow speed,a steady parameter of traffic flow,as a main indicator,parameters estimation,hypothesis test and confidence interval analysis are jointly used to determine the health condition of traffic detectors.The methodology is demonstrated through application to the historical and realtime data in the Advanced Traffic Management System of Shanghai urban expressway system,with validation by floating car measurement.
HUANG Xiaoming , BAI Tao , LI Chang , JIN Jing
2011, 39(7):1026-1030. DOI: 10.3969/j.issn.0253-374x.2011.07.015 CSTR:
Abstract:Temperature warping stress of plain concrete plate calculated by Westergaard formula and finite element method (FEM) was comparatively analyzed.It demonstrates the applicability of plain concrete plate model,and an important conclusion is drawn that body weight produces no effect on warping stress.Based on threedirection spring simulating the bondslip relation between steel and concrete,warping stress alteration of feature points before and after reinforcement was calculated.Influence of the following parameters on the change of warping stress before and after reinforcement could be neglected,such as reinforced layer location,bondslip stiffness coefficient,temperature gradient,plate length,plate thickness and reinforcement ratio.The results show that temperature warping stress calculation method of separate plate of continuously reinforce concrete parement (CRCP) under Winkler foundation is the same as its size of ordinary Portland cement concrete slab.
LI Feng , HUANG Songchang , XU Jian
2011, 39(7):1031-1034. DOI: 10.3969/j.issn.0253-374x.2011.07.016 CSTR:
Abstract:The expansion ratio and the halflife are usually utilized to evaluate the characteristics of foamed bitumen at present,but it’s hard to determine the optimum foaming parameters due to lack of definite numerical evaluation criteria.Therefore,an index is developed in this study to solve the problem.One of the existing decay equations is chosen as the basic form of the foamed bitumen decay equation.Then the general equation is derived by differential for the actual maximum expansion ratio,and a general decay equation is obtained with corrected boundary conditions of foamed bitumen decay.The foam energy index is defined from the view of energy,and the index formula is derived by integral.The foaming test data of four kinds of bitumen used in actual works are analyzed.The result shows that the foam energy index quantifies the bitumen foaming characteristics with a clear physical meaning,and it can be used to determine the optimum foaming parameters and evaluate the characteristics of different foamed bitumen.
ZHANG Song , WU Guangqiang , ZHENG Songlin
2011, 39(7):1035-1039. DOI: 10.3969/j.issn.0253-374x.2011.07.017 CSTR:
Abstract:Energy management strategy is related to fuel consumption and exhaust emissions of plugin hybrid electric vehicle (PHEV).Vehicle simulation model is established on the basis of energy management strategy developed in this paper.A hybrid optimization algorithm is proposed to overcome the inherent defects in single optimization algorithm by combining the improved particle swarm algorithm and genetic algorithm (GA).The hybrid optimization algorithm is applied to the multioptimization of energy management strategy of PHEV.Optimization results show that the hybrid optimization algorithm can avoid falling into local optimum and its search capability is much better than simple particle swarm optimization(PSO) and GA.The optimized fuel consumption and the exhaust emissions reduce around 30%.
2011, 39(7):1040-1044. DOI: 10.3969/j.issn.0253-374x.2011.07.018 CSTR:
Abstract:From the view of software development mode and architecture,the control system of dual clutch transmission (DCT) is analyzed.Based on the kernel of the embedded real time operating system μC/OSⅡ,the software architecture of DCT control system is established.The complicated control of DCT shifting process is implemented by using finite state machine (FSM),and DCT control system is developed according to the software architecture of control system.In the platform of DCT hardwareintheloop simulation,the function and performance of control system software are tested.The results show that the software can not only ensure the realtime requirements of DCT control system,but also enhance its stability and scalability.
LI Qiliang , YANG Zhigang , CHEN Feng
2011, 39(7):1045-1049. DOI: 10.3969/j.issn.0253-374x.2011.07.019 CSTR:
Abstract:Pressure and velocity fields of flow over an outside rear view mirror are investigated by wind tunnel test and numerical simulations,and their results are compared.The agreement of average static pressure and average velocity,standard deviation and power spectral density of fluctuating velocity between the results from wind tunnel test and the results from numerical simulations indicates that test results and numerical results validate each other,and the numerical simulation approach is feasible and can reflect the flow field characteristics of mirror.The features of the flow field downstream the mirror,as reflected by the average static pressure distribution of test section floor,show that the position where the energy dissipation is the strongest is located at one diameter distance downstream of the mirror,and the recirculation zone can affect the flow field three diameters downstream of the mirror.High intensity fluctuating velocity can be found at the wake of mirror and their energy are foucs on low and middle frequency.The strength of fluctuating velocity at the shear layer region is larger than other regions.At the shear layer region,the σ(u′)/u进 value can reach 0.3 at certain point.
SHEN Xiaojun , FAN Hao , WEI Li , ZHANG Yicheng
2011, 39(7):1050-1055. DOI: 10.3969/j.issn.0253-374x.2011.07.020 CSTR:
Abstract:Based on PSCAD/EMTDC,the paper first presents an objectoriented modeling method for urban rail transit vehicle electrical modeling,the model including the main propulsion system,brake resistors,filter circuits,auxiliary systems,resistance calculation,driving control and many other units.A vehicle simulation and test based on Shanghai Metro parameters were made with the model.The simulation data are consistent with the measured data,which proves the established simulation model to be able to simulate accurately the vehicles in different electrical characteristics and exercise characteristics.
WANG Anlin , SHI Zhongqiu , HU Yuqin , ZHANG Qi
2011, 39(7):1056-1061. DOI: 10.3969/j.issn.0253-374x.2011.07.021 CSTR:
Abstract:To theoretically reveal the reasons for instantaneous failure of cartridge valves in integrated control hydraulic system,concrete pump hydraulic system was taken as an example,an analytical method of cartridge valve’s on and off states combination based on fluid logic theory was proposed.And this method was testified by the digital model of concrete pumrp hydraulic system.The research result shows that within a certain range of load,an improper opening of single cartridge valve will cause connectivity between the cavities of different valves,which will lead to instantaneous failure to integrated control hydraulic system,but increasing control cavity pressure of cartridge valves can solve the instantaneous failure problem.Finally,the paper presents a design method to increase the working stability of the integrated control hydraulic system.
CAI Yinqiao , TONG Xiaohua , SHU Rong
2011, 39(7):1062-1067. DOI: 10.3969/j.issn.0253-374x.2011.07.022 CSTR:
Abstract:A laser scanner using linear array scanning for fast threedimentional imaging is introduced.Both the system structure and operational principle are presented.Based on the analysis of the emitting and receiving path of the laser beam,the rigorous imaging equations of the laser scanner is deduced starting from one unit of the array detector by means of the optical principles and analytic geometry knowledge.The main internal and external fators undermining the imaging quality of laser scanner are also discussed.The outfield test shows that in the distance of 30 m the vertical resolution of the instrument is 5 cm,while in the direction perpendicular to that of ranging targets with diameter can be detected bigger than 8 cm,and that the standard error of residuals in the fitted plane is about 5 cm.
ZHU Weidong , LI Quanhai , XU Keke , LI Tianzi
2011, 39(7):1068-1073. DOI: 10.3969/j.issn.0253-374x.2011.07.023 CSTR:
Abstract:According to the characteristics of hyperspectral remote sensing images such as multiband and data redundancy,a novel fusion method of hyperspectral remote sensing images based on the second generation Bandelet and PCA transform was proposed.Bandelet transform was performed to gain Bandelet coefficients and geometries of subbands.Then PCA transform was performed to calculate their principal component.Finally,fused images were reconstructed with their principal component by taking inverse Bandelet transform.The experiment shows that this method can well merge hyperspectral remote sensing images.Its result is better than those of Bandelet and PCA transform method.
LIU Zhiping , HE Xiufeng , ZHANG Shubi , WANG Jian
2011, 39(7):1074-1078. DOI: 10.3969/j.issn.0253-374x.2011.07.024 CSTR:
Abstract:The shortcomings of both the singleepoch method and the similar singledifference approach for GPS deformation monitoring are analyzed,and then the dynamic tripledifference (DTD) method,which uses single frequency carrier phase observations of two epochs tracking continuously by tripledifference,is proposed for dynamic deformation estimation of the structural monitoring with single frequency GPS.The DTD method is characterized by its nonambiguity resolution,lower accuracy requirements for initial values of reference station and baseline vectors,and unnecessary upperbound restriction to the actual deformation.Thus,the DTD method is expected to be superior to the existing methods for its dynamic features of realtime structural monitoring.Finally,structural vibration monitoring method is applied to the third bridge of Nanjing Yangtze River.Deformation by DTD method is consistent with that by singleepoch method in about 5 mm root mean square error.Moreover,with the empirical mode decomposition (EMD) and Fourier spectrum analysis,the spectrum of the bridge dynamic deformation derived from the proposed method exhibits a dominant peak at 0.25 Hz,which coincides with that obtained from finite element computation.
CHEN Liuhua , GAN Lihua , ZHAO Yunhui , LIU Mingxian
2011, 39(7):1079-1083. DOI: 10.3969/j.issn.0253-374x.2011.07.025 CSTR:
Abstract:Flurbiprofen liposomes were prepared by thin film evaporation and ultrasonic technique.The encapsulation efficiency and drug loading of flurbiprofen liposomes were determined with the protamine aggregation method.The impact factors on drug carrying characteristics of flurbiprofen liposomes were discussed.The results indicate that flurbiprofen liposomes have good dispersion and their average diameter are about 100-250 nm.Flurbiprofen molecules were located in the hydrophobic group region of liposomes and the partition coefficient KD of flurbiprofen between the liposomes and the aqueous phase was 815.6.The obtained liposomes have better entrapment efficiency and drug loading when the concentration of lecithin is 5.4×10-4 mol·L-1.With the increase of flurbiprofen/lecithin mass ratio,the drug loading of flurbiprofen liposomes increases,while its encapsulation efficiency decreases.Cholesterol can adjust the stability of liposomal membrane and the mass ratio of cholesterol to lecithin should be lower than 0.3.However,higher cholesterol concentration makes a great amount of cholesterol insert into membrane and leads to larger membrane rigidity,which decreases the entrapment efficiency and drug loading of liposomes.
WANG Xiaogang , WANG Yao , FAN Yajuan , LI Jing
2011, 39(7):1084-1087. DOI: 10.3969/j.issn.0253-374x.2011.07.026 CSTR:
Abstract:A novel electrochemical sensor was prepared by direct electropolymerization of DLaspartic acid on the surface of glassy carbon electrode in aqueous media.In pH 4.5,0.1 mol·L-1 HAcNaAc buffer solution,the film modified electrode exhibited excellent adsorption capacity to ferulic acid and improved the electrochemical responses significantly.The action mechanism of modified electrode was preliminarily explored,and a fast analytical method for ferulic acid was established.In the range of 9.1×10-7 to 3.0×10-3 mol·L-1,the differential pulse voltammetric peak current had a linear relationship to the concentration,and the detection limit was estimated to be 3.1×10-7mol·L-1.This method was adopted to detect the trace amount of ferulic acid in Chinese patent medicine of Xiaoyao Pills,and the recovery was from 97.9% to 102.2%.
2011, 39(7):1088-1092. DOI: 10.3969/j.issn.0253-374x.2011.07.027 CSTR:
Abstract:The firm bond with extendable maturity endows the firm with the right to extend the maturity of the bond according as the level of market interest rate,by which the firm can evade the adverse movement of interest rate.For this right,the firm should compensate the investors of the firm bond.Besides the risk of interest rate,the investors will bear the credit risk in the extended period.We deal with the credit risk by reduced form approach.Under the assumption of stochastic interest rate,we obtain the pricing formula for firm bond with extendable maturity by PDE approach and compare its return rate with that of ordinary firm bond.
2011, 39(7):1093-1098. DOI: 10.3969/j.issn.0253-374x.2011.07.028 CSTR:
Abstract:China and ASEAN’s economic cooperation is imperative with the development of regional cooperation and economic globalization.This paper sets the 16 national ports in Yunnan as research objects,and points out the key issues of the current situation,based on the thorough analysis on the characteristics of the distribution and exchange of the ports transportation in Yunnan Province.With the hubandspoke model,it counts the transport linkage,and then divides the ports transport into two big systems,one is ChinaMyanmar,and,the other is ChinaVietnam.At last,it points out the priority development regions,which may be helpful to develop the “bridgehead” and “the open and experimental border areas” of Yunnan Province.
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