Abstract:Changshan Bridge is an extradosed cablestayed prestressed concrete bridge with two cable planes. Its 260m main span is the longest among the same type of bridges. In order to ensure the reliable force resistance of its main girder, a new beam type, i.e. spine beam, was proposed firstly based on the forcetransmission mechanism between the cables and girder. Furthermore, the layout scheme of the multidirectional mixed internal and external prestressing tendons was determined through optimization analysis, especially the bow prestressing tendons arranged at the bottom flange of the main girder. The stiffeners installed in the triangular side boxes rather than diaphragm were used to transfer lateral forces. The fullbridge finite element model was established for numerical analysis. The calculation results show that the stress and deflection of the full bridge are far below the specification limits under the most unfavorable condition. The shear lag of the main girder is significantly improved. The lateral force of the main girder is more uniform and reasonable.

Abstract:Influence of defect length on the signal output from the magnetic flux (MF) examination of bridge cables for quantitative evaluation was studied. Model experiments were conducted to inspect the characteristics of signal output from the MF examination, and to verify the conclusions from magnetic circuit analysis. Finite element method was used to analyze the sensitivity of the defectlength effect to parameters including the defect morphology, percent loss of metallic area (LMA), cable diameter, size of the test device et al. The results show that fluctuation of the signal from the MF examination of the bridge cable is proportional to the percent LMA, and may be disturbed by the length of flaw; the magnetization intensity of steel wires attenuates approximate linearly along the radial direction of cable; the defectlength effect in bridge cable is more significant than that in steel ropes or rods; when the flaw is shorter than the net distance between the magnets, the damage will be underestimated if the defectlength effect is neglected.

Abstract:A typical spherical concrete flying object was selected to study its impact effect on a typical roof clay tile. Based on ANSYS/LSDYNA and dropball impact experiment, a finite element model was established to study the impact effect of windborne spherical concrete debris on a clay roof tile. The JohnsonHolmquistCeramic constitutive model was chosen to simulate the mechanical properties of clay roof tiles, the element strain failure criteria were introduced to simulate the breakage of tile, and the explicit dynamic algorithm was used to study the time history of the tile stress, strain and deformation during the dropball experiment. The impact effect of tile inclination angle, sphere impact velocity and mass were analyzed. The results show that the maximum von mises stress of the tile is approximately proportional to both the impact velocity and the sphere mass. By contrast, the stress is unrelated to the tile inclination angle. The energy transfer during the process of impacting was remarkable, and the clay roof tile can endure the impact effect of the spherical concrete debris when the wind speed is less than 34.35 m?s-1 according to the function.

Abstract:A pit supported with a wall formed by hatshaped sheet pilings was modeled in centrifuge apparatus to investigate the earth pressure against the wall during excavation. A parallel test using a planar wall with equivalent bending stiffness was also conducted to demonstrate the effect of the extruding surface of the sheet pile wall on the earth pressure distribution. The results show that the distribution of earth pressure on the sheet pile wall is influenced by the crosssectional shape of the wall. The earth pressure against the extruding and denting portions of the wall differs at the same elevation, and the difference is affected by the displacement mode of the wall. The earth pressure against the denting portions is larger than that of the extruding portions when the wall moves away from the soil; it becomes opposite when the wall moves towards the soil. The displacement mode of the wall changes during excavation, and this further complicates the spatial distribution of earth pressure which varies with the elevation.

Abstract:To investigate the seismic behavior of grouted sleeve lapping connector, pseudostatic experiments were conducted on a castinplace shear wall and two different precast shear walls in which longitudinal reinforcement were connected by typeⅠand typeⅢgrouted sleeve lapping connector respectively. Initial crack appeared at the bottom of the castinplace shear wall, while for the precast shear walls, the initial crack appeared above the sleeve due to the vertical confinement of sleeve, and the cracking load of the precast wall was greater than the castinplace wall. At the ultimate stage, concrete were crushed at the root of the castinplace shear wall; the concrete cover around the sleeve peeled locally and then was destroyed, following the crush of the concrete above the sleeve in the precast shear walls. The ultimate bearing capacities of the two different types of shear wall were almost same. Compared to the castinplace shear wall, the cracked degree, yield load and ultimate displacement of the precast shear walls were larger, the ductility of the precast shear walls was a little lower. Due to the densification treatment of the horizontal bars in wall body and the stirrup of rim member in the region of sleeve, the energy dissipation of the precast shear walls was better than that of the castinplace shear wall. The strain curve of the steel bar above and below the sleeve is consistent, which shows that both typeⅠand type Ⅲ grouted sleeve lapping connectors performed well in transferring the stress of the steel bar.

Abstract:The logspiral cone failure mechanism of threedimensional slopes was built based on the upperbound limit analysis method. The present method was verified by comparing the results with the published data of the classical literature. The energy dissipation due to soil volume compression was neglected and the corresponding influence on the stability of threedimensional slopes was investigated. Then, the effects of soil nonhomogeneity on the stability of threedimensional slopes with different inclination angles, internal friction angles and ratios of width to height were explored. The results show that the influence of the energy dissipation due to soil volume compression should be considered when the internal frication angle is large but the inclination angle and the ratio of width to height is small. However, when both the internal friction angle and the inclination angle are large or just the internal friction angle is small, the energy dissipation due to soil volume compression could be neglected. The stability of threedimensional slopes decreases with the increase of nonhomogeneity and the decrease magnitude becomes larger when the slopes have smaller inclination angles or larger internal friction angles. In addition, the threedimensional effects of slopes are reflected by ratios of width to height. Slopes with stronger threedimensional effects are greatly affected by nonhomogeneity. When the nonhomogeneity is very strong, the stability factors of slopes with stronger threedimensional effects are smaller than those of slopes with weaker threedimensional effects.

Abstract:Base on the digital image correlation (DIC) technique, soil displacements and corresponding earth pressures induced by pressin process of pile model tests were studied. In the model tests, the vertical accumulative soil displacements were tracked without marks. The soil displacement trajectories were plotted, which revelated that pile pressin process caused different soil displacement paths at different depths and locations. Through joint analysis on the vertical displacements of soils around the pile and the corresponding earth pressure, the mechanism of earth pressure change was explained from the perspective of soil deformation. It shows that the displacement and earth pressure induced by advance of pile were conjugative. Finally, the influence of pressin velocity on soil displacements was investigated. The analyses presented in this study tended to further clarify the squeezing effect caused by pile pressin process and the mechanism of the development of earth pressures around the pile.

Abstract:A total of 16 concrete independent foundation slabs with different widthtoheight ratios and hypotenuse slopes were tested under uplift load, and the failure modes and uplift bearing capacities of this type of foundation slab were studied. Based on the test results, the effects of widthtoheight ratio and hypotenuse slope on uplift bearing capacity of foundation slab were also analyzed and compared. The experimental results showed that, the uplift bearing capacity decreases obviously with the increase of hypotenuse slope when the widthtoheight ratio, the size of slab and steel reinforcement are the same. In addition, the results also showed that when the hypotenuse slope and the size of slab are same, the uplift bearing capacity of foundation slab is gradually reduced with the increase of widthtoheight ratio. The results of this study can provide experimental basis for the concrete independent foundation slab in proposing the design method of uplift capacity.

Abstract:A method was proposed to calculate the pile bearing capacity loss induced by the tunnel excavation underneath the pile. The hyperbolic loadtransfer function considering the effect of tunnel excavation at the pilesoil interface was compiled and based on it, the Q~s curves of the pile and that after tunnel excavation were figured out. Ultimate bearing capacity of pile was confirmed where pile settlement was fifty millimeter, and it was used as the indicator to measure the influence caused by the excavation. The variation of bearing curve and pile forces as well as influencing factors to the bearing capacity were analyzed based on one work point of Hangzhou Metro Line 1. The bearing capacity loss of pile is 22% when volume loss rate is controlled at 0.5%. After tunnel excavation, there is a position in the pile where the lateral friction is unchanged, while the lateral friction increases upper the position and decreases bellow the position. The bearing capacity loss has a positive correlation with volume loss rate and Initial load of pile, however, has a negative correlation with the distance between the bottom of the pile and the top of the tunnel.

Abstract:The modeling to discrete the continuous process of the coexistence of the fatigue crack initiation and wear growth was presented. Then, a threedimensional rail model for predicting the coexistence of the fatigue crack initiation and wear was established according to the theories of critical plane fatigue damage and Archard wear. The effects of different friction coefficients between wheel and rail contact positions on fatigue crack initiation and wear growth was analyzed. Results show that the friction coefficient has a great influence on the distribution of the adhesive and slip area, and the tangential stress in wheelrail contact patch, but has little effect on the size, shape and location of the contact patch. When the friction coefficient increased, the average wear growth rate and wear amount increased while the crack initiation life reduced. For example, with the increasing of the friction coefficient from 0.3 to 0.7, the average wear growth rate of the high and low rails increased about 17%~55% and 16%~42% respectively, and crack initiation life of them decreased about 24%~34% and 18%~35% respectively. The crack initiation position in the high rail was at about 2.0~2.5 mm below the rail surface and moved upward to 0.9~1.0 mm with the increasing of the friction coefficient. And the crack initiation position in the low rail kept at about 2.4~2.6 mm below the rail surface with the increasing of the friction coefficient. It can prolong the crack initiation life and reduce the wear of the curve rails to keep the friction coefficient at 0.3~0.4 between wheel and rail contact positions.

Abstract:In order to realize realtime monitoring of pavement temperature of the whole expressway, continuous pavement temperature data were collected using a mobile traffic meteorological monitoring system where was fixed a traffic meteorological station, and a temporal and spatial pavement temperature data processing method was studied under different weather conditions, and a relative pavement temperature distribution map was drawn, and the relative pavement temperature difference between different positions and the fixed traffic meteorological monitoring station were obtained, and the pavement temperature at other locations were calculated. This paper shows a set of processes and methods for data collection, fusion processing, and descriptive presentation of pavement temperature, and the accuracy reaches 92.31% within allowable error range of ±1℃. All these results are in order to monitor effectively pavement temperature of long distance, identify low temperature and easy icing sections, which will provide a strong technical support for enhancing levels of operation management, maintenance decision and emergency service of icing risk sections in winter.

Abstract:Conditionalbased maintenance (CBM) can reduce the possibility of machines’ failure, but the stoppage resulted by CBM will affect the system’s throughput. In order to minimize the impact of CBM, a realtime maintenance decision method was proposed. First, a mathematical model based on Markov process model was developed to describe the system dynamics. Second, the model quantified the impact of system stoppages on the throughput by calculating the permanent production loss. Finally, a control algorithm was developed to optimize CBM decisions. A simulation case study was performed to validate the effectiveness of the model.

Abstract:When designing the power source configuration of fuel cell bus, only the power and fuel economy during the driving process were considered, and the impact of the other stages of the vehicle was ignored. In view of this situation, the energy consumption and emissions of fuel cell bus in all life cycle stages were analyzed based on the LCA (Life Cycle Assessment) theory, and a LCA model of fuel cell bus was established. By analyzing the life cycle energy consumption and emissions with Chinese urban bus driving cycle, the results showed that the power source configuration of fuel cell bus could be optimized. The optimal scheme of power source configuration was obtained by using genetic algorithm. The life cycle energy consumption and emissions of the fuel cell bus with optimal power source configuration were lower than those of the battery electric bus by, respectively, 24.86% and 25.76%, and were lower than those of the fuel cell bus with highpower fuel cell system by 12.11% and 6.51%, respectively.

Abstract:To analyze the main sources of low frequency noise in highspeed trains, the structural vibration and acoustic radiation theory was used to study the relationship between the characteristics of the sound field in the vehicle and the vibration of the interior plates. The experimental results show that the vibration of the interior plate and the coupling response characteristic of the sound field in the vehicle are universally applicable in the process of acoustic and structural sound propagation. This method is applied to analyze the noise characteristics of a highspeed train under different speed levels, open lines and tunnel conditions. The results show that, the higher the running speed of the train, the more significant the amplitude of the low frequency vibration of the interior panel increases, which leads to the peak of the low frequency noise in the car. Under 350km?h-1 operating conditions, the low frequency noise peak mainly originates from the floor vibration and the increase of the noise in the tunnel environment is due to the sidewalls and ceilings acoustic radiation. The contribution of each panel was quantified. Finally, the operational transfer path analysis (OTPA) method was used to quantitatively calculate the noise contribution of noise sources. The results show that the aerodynamic noise proportion is the largest, but the sum total of vibration excitation of 60%, especially at the peak frequency of 160 Hz, the contribution of the cooling fan vibration is the largest.

Abstract:This paper presents a study on microscopic mechanism of the weartype rail corrugation and proposes a wavelength locking mechanism of worn profile rail corrugation. The microscopic formation mechanism of rail corrugation was analyzed under this wavelength locking mechanism. A smallscaled roller rig with two simulation wheels has been designed to verify this formation mechanism of the rail corrugation by experimental and the corresponding line tests were also carried out. The lateral creep forces at variable loadings can be measured in this test rig. The creep forces vs. creepage rate curves have been obtained under variable loadings. The results have compared against with the micro mechanism of rail corrugation proposed. It is proved that the theoretical analysis of the microscopic mechanism of wear type rail corrugation. Therefore, this validated theory can be used to explain phenomenon of many types of rail corrugations.

Abstract:A rigorous calibration model of inclinometer in TBM (Tunnel Boring Machine) was derived. The twoaxis angle data collected by the inclinometer was considered as point clouds of a plane, and a method of robust estimation was derived. On the basis of the above model and method, a rigorous combined model was proposed to solve the Fusiondata of prism and inclinometer by using the method of least square collocation. Finally, the above model and method were analyzed and verified by experiment, and the results showed that the proposed model of shield configuration is feasible.

Abstract:The Baarda’ data snooping method detects the outlier by making decision between the null and alternative hypotheses. Based on this method, usually only the false alert and missed detection were considered and the possibilities were defined for the minimal detectable bias (MDB). Nevertheless, in practical application, there are always multiple alternative hypotheses. Therefore, a third type error  wrong exclusion  occurs, which was caused by the correlation between two test statistics. The probabilities of false alert, missed detection, wrong exclusion can be considered as functions of the correlation coefficient. Monte Carlo methods were used to calculate the possibilities of these three types of errors with different correlation coefficients for two alternative hypotheses. It has proved that when the correlation is high the probability of committing wrong exclusion increases exponentially. As a result, the discrepancy between the theoretical and realistic MDB values enlarges, and accordingly the confidence level and the system reliability decrease. Finally, numerical experiments were conducted to analyze and compare the performance of two examples with different geometry conditions.

Abstract:GPS satellites antenna PCO(phase center offset) and PCV(phase center variation) were reestimated based on station coordinates under different reference frames. The correlations among GPS satellite antenna parameters, receiver antenna parameters and reference frame scales were reduced by fixing receiver antenna PCO/PCV and constraining station coordinate to given reference frame tightly. Results show that the mean difference of blockspecific satellite antenna PCV based on different reference frames is 0.726 mm. Comparing with the satellite antenna PCV released by IGS based on IGS00, the mean blockspecific PCV difference between IGS value and the reestimated is 0.844 mm. Comparing to the IGS values, GPS reestimated satellite antenna PCO has an average bias of -14.4 mm and -16.8 mm for the reestimated satellite antenna PCO based on IGS14 and IGS08, respectively. The reestimated PCO/PCV values could improve their inerconsistency and contribute to the GNSS based reference frames densification.

Abstract:This study presents the compositions of major oxides including SiO2, FeO, Al2O3, MnO, CaO, MgO and TiO2 in the detrital garnet grains separated from the sediments of the Changjiang River and its major tributaries. The main garnet assemblage consists of almandine, grossularite, Grossular and spessartine, with the mean contents of 65.4%, 13.8%, 9.4% and 11.5%, respectively. The typical garnet assemblage of Changjiang sediments on the GPAS triangular diagram is characterized by low Mg and high Mn contents, which suggests they are mainly sourced from intermediate and lowgrade metasedimentary rocks. These garnet compositions are primarily determined by the widely distributed schist, phyllite, marble and the lowtemperature and lowpressure contact metamorphic rocks in the Changjiang catchment. Our data also suggests that the Jinshajiang River as the largest tributary in the upper drainage is the major supply of fine sands to the Changjiang mainstream. Similar to the average composition of the whole Changjiang sediments, the garnets of Jinshajiang are characterized by low Mg and high Mn contents, but much different to those of the middle and lower reaches. Therefore, the garnet assemblage of the Jinshajiang can indicate the contribution of Changjiang fine sand in the sediments provenance study of East China marginal seas.

Abstract:Change rule for the study of the thermal physical parameters of rock and soil mass can occurrence characteristics of shallow ground temperature,such as using the thermal response test and the research methods such as laboratory test and analysis of geotechnical engineering (thermal conductivity),porosity,thermal conductivity,specific heat,scientific analysis,parameters,such as using IGSHPA line heat source model and INGERSOll cylindrical heat source model to carry out the analysis of characteristics of coefficient of thermal conductivity changes.The results show that the average thermal conductivity of strata in the area is 1.68～3.44W? (m?K)-1,and the high value area is located in bedrock mountainous area.Formation of initial ground temperature range of 10.80～15.80℃,the high value area in east and west on both sides of bedrock mountains and piedmont zone.Under the condition of natural moisture content,the thermal conductivity of the rock and soil body shows an obvious trend with the change of water content,particle density and porosity,that is,it gradually decreases with the increase of water content,increases with the increase of particle density and gradually decreases with the increase of porosity.As the diameter of borehole increases, the thermal conductivity of borehole decreases and the thermal resistance of borehole increases obviously.And the initial temperature of 1.0°as a standard for geothermal recovery,sticky soil layer recovery needs 5d,coarse sand formation in the recovery of 3d; And the initial temperature of 0.5°as a standard for geothermal recovery,sticky soil layer recovery need 15d,coarse sand formation in the recovery period for 7d.