Applied Mechanics and Materials Vols. 405-408

Abstract: By analysis its own characteristics of Reconstruction and Extension freeway slope, summary and presents the main factors affecting slope stability; then use orthogonal test method, analysis the result by Range Method, it indicated that the sensibility of impact factors on the Stability of Reconstruction and Extension Freeway Slope was in the following order: the slope angle after excavation, cohesion, weight of soil layer, internal friction angle, the slope angle before excavation, Cable length, Cable spacing.

Abstract: The finite element method was used to analyze the deformation and stress of track in different length and height of gaps under the train load. In order to study the influence of gap between the slab and emulsified cement asphalt mortar of china railway track system II slab track on the subgrade, a model of CRTS II slab track was established on the base of elastic foundation beam theory and finite element software ANSYS. The results show that gap between slab and CA mortar has significance effect on the stress and deformation of track structure. The deformation of rail and slab, the longitudinal stress of slab were increase with the increase of gap length, but has less effect on lateral stress of slab. When the length of gap exceed to 1.95m, the deformation and stress have the tendency of increase sharply, the length of gap between slab and CA mortar should not exceed 1.95m. The gap between slab and CA mortar has effect on the durability and lifetime of ballastless track, so the gap should be maintenance timely.

Abstract: The high temperature stability of SMA is affected by many factors. Some factors that may affect the high temperature stability of SMA (stone mastic asphalt) analyzed by the way of Marshall and rutting testing, in the laboratory. The results show that the high temperature stability of SMA is closely related to its gradation,asphalt content,testing temperature,the number of rolling. This paper will only discuss the above factors. Study results indicated that adding proper coarse aggregate (diameter4.75mm ) and mine dust contents would play occluding and wedging role in aggregate mixture. The rolling times of SMA asphalt mixture should be Strictly controled, in order to improve the compaction density. When the experiment temperature was increased up to 67°C, high-temperature stability of SMA can not meet the requirement of standards. The optimal dosage of asphalt in rutting test is 5.0%, which is more 0.3%~0.4% than that in marshell-test. Key words: road engineering; SMA; rutting testing; Marshell test; high temperature stability

Abstract: In order to study the chemical composition of volcanic rock and physical properties in Hainan province, used the method of X-ray fluorescence, analysises on its chemical composition, and researched the physical properties of volcanic rocks including density test, porosity test, acoustic test, resistance test. The results showed that: the volcanic rock is tholeiitic at the cavity of lava area in Hainan province, P-wave velocity and S-wave velocity would change with the changing of porosity.

Abstract: A dynamic model of vehicle-bridge interaction is presented considering the railway vehicle moving through bridge with varying velocity. Assuming the vehicle has a constant acceleration, the motion equations of coupled vehicle-bridge system were deduced based on DAlemberts principle and theory of Euler beam. Dynamic responses of system were analyzed both cases of the acceleration and drag acceleration for a moving car. Results show that the amplitudes of vibration of the system will enlarge sharply with the acceleration of vehicle increasing, and the maximum of responses occur when the vehicle moving at the middle point of bridge. In addition, the stiffness coefficient is one of the key factors to affect on dynamic responses of system. Generally, the suitable rigidity of structure is much important to decrease the responses and suppress the vibration of system.

Abstract: Determination of a runway orientation is a critical task in the planning and design of an airport, and runway orientation is made according result of wind coverage. But there are many shortcomings in current method of wind coverage calculation, such as less precision, process miscellaneous and result simplex, when using the method in determination of a runway orientation. Aim at the situation, through analysis the relation between wind direction and runway orientation, the method is built that becoming all wind to cross wind for runway. Then according annual wind statistic data and requirement of max cross wind, frequency of cross wind exceed limited value for eight runway orientation are calculated in certain airport area. According the result, relation curve between frequencies of cross wind exceed limited value and runway orientation is made. Now, the best and all possible orientation for runway is get under requirement of max cross wind. At last, the method for determination of a runway orientation based on frequency of cross wind is put forward, and the method is a new thought for planning and design of an airport.

Abstract: Fire prevention system of subway station plays an important role in ensuring passenger safety. The Shenyang Youth Street subway station fire prevention system safety was studied, applying performance-based fire protection design analysis method, using of FDS simulation software on the station fire prevention safety system for the calculation and analysis. Three working conditions were set when subway fire happens. Fire smoke flow characteristics and the distribution of temperature, CO concentration and visibility were analyzed and compared. The results show that the automatic sprinkler system and smoke control system have great effect on the preventing spread of fire. In the automatic sprinkler system and smoke control system conditions, fire hazards have not reached the standards of passengers tolerance.

Abstract: Restricted by terrain, intersections in Mountain cities are always deformity intersections. Based on the researches on deformity intersections in Chongqing, this article establishes basic information database of these intersections, and then select the main impact factors of capacity among these deformity intersections through the evaluation method of principal component analysis, and provides a theoretical basis for study on capacity improvement of deformity intersections in mountain cities.

Abstract: Rutting is one of the most hazardous damage form of asphalt pavement.But,owing to itself inherent in the viscoelastic characteristics of asphalt mixture,the diversity of factors influencing the high temperature of asphalt pavement anti-rutting performance and the complexity of rut formation,this three reasons make ruts become a worldwide problem.Starting from the mixture.This article analyzed the influence factors of the rutting resistance of asphalt mixture at high temperature.For asphalt mixture, through the experimental data, the research status at home and abroad, from the type of asphalt, asphalt content, grading of aggregates and air voids four aspects analysis and study the influence factors of the stability of asphalt mixture at high temperature.

Abstract: The high pier and large-span bridge is high, soft, and have large contact area with the outside world, under the action of wind load, it will occur large vertical and horizontal displacement .This displacement effect on the track structure and will cause rail additional force, lateral displacement and create initial track irregularities, and then reduce the lateral stability of track structure. In this paper, through the large finite element software, we build pier-beam-track model to simulate and analyse the influence on the track structure under the vertical and horizontal wind load, it reached the following conclusion: horizontal wind load basic does not cause rail additional force, but reduce the rail lateral stability; longitudinal wind load can make rail produce certain vertical additional force, but compared to the telescopic additional force, the force basic can be ignored.