Applied Mechanics and Materials Vols. 505-506

Abstract: Aimed at the feature of expressway subgrade drainage facilities in typical red sandstone areas in Jiangxi province and based on the importance of the structure, damage conditions, service requirements and the current specification requirements related to various types of ditches, the designed repetition period of rainfall and proposed safety depth values for drainage facilities were put forward by considering reasonably the key design parameters to regional drainage facilities. The relationship between prerequisite of discharging sediment in ditches or conduits and minimum longitudinal gradient was discussed. Combined with the characteristics of red sandstone subgrade drainage with high requirements, the design elements of red sandstone area expressway subgrade drainage system were obtained, which can provide beneficial references for the subgrade drainage design in red sandstone areas.

Abstract: A method for increasing the height of the post was proposed according to the problem of barrier height reduction resulted from highway pavement overlay, which is simple and can be adapted to different pavement thickness, so that barrier restored to its original height. Through computer simulation of the post height barrier crash performance reliability and a comparative analysis, the results show that the post heightening program can meet the performance requirements of the barrier crashworthiness.

Abstract: A vehicle-track-subgrade coupling vibration system model was proposed to analysis the influence of cell plate length to slab track vertical dynamic response. The model was built with finite element method, rail was modeled as space beam element, both track plate and base plate were modeled as shell element, the vertical connections between rail, slab and subgrade were modeled as spring-damper element. The results show that with the cell plate length increases, the vertical vibration displacement of rail, track plate and base plate have decreasing tendency; the vertical vibration acceleration of rail has increasing tendency; the vertical vibration acceleration of track plate and base plate have decreasing tendency.

Abstract: Three problems remained to be solved in the analysis of the seismic stability of high-fill embankment: the pseudo-static method was defective, the embankment damage model was not clear, and the stability evaluation index was still to be discussed. It analyzed the dynamic response of a typical transect of high embankment with FEM to find out its instability mechanism. Then it chose the most dangerous sliding surface and analyzed its stability. The selection of the evaluation index of the seismic stability of high-fill embankment was discussed at last. The results show that the upper embankment, especially the shoulder is easily to be damaged. It is too conservative to use the safety factor as the involution index of the seismic stability of high-fill embankment, and the permanent displacement is a better choice.

Abstract: The past rail wear measurement methods and equipments are summarized and the development process of portable inspection car for measuring rail wear is presented. The measurement system of this portable inspection car is developed based on the software platform of Labview. The car structure design is delicate and matched well with the image collecting device. This portable inspection car can measure the rail wear every 2.5 cm along the railway line and the measuring accuracy is 0.1mm.

Abstract: In order to study the dynamic response law of semi-rigid base of asphalt pavement under heavy load traffic, the viscoelastic system model under heavy load was established based on measured loading pattern and axle load distribution with the finite element software ANSYS12.0. Heavy load traffic effect on the dynamic response of semi-rigid base of asphalt pavement was discussed . The results show that semi-rigid asphalt pavement structure dynamic response value changed with the increase of axle load; time varying regularity of stress and strain was not the same in different directions.

Abstract: Based on the experimental study of the gravel layer under the horizontal vibration load, and the variation of particles response behavior according to experimental phenomenon, we study the distribution of the shear along the depth direction, propose the main factors which affect particle moves and dynamic stiffness and their distribution in the granular packs. Then deduce the probability distribution model under horizontal vibration by the stochastic theory, and discuss the prediction method.

Abstract: By using the finite element method, the settlement of soft soil subgrade with a crust layer has been investigated. To find the influence of thickness of the crust layer on the settlement, four different thicknesses, which are 0.0m, 1.5m, 3.5m and 5.5m, are selected. Besides, the settlement during the construction and post construction are also analyzed. It is found that the crust layer can reduce the settlement and uneven settlement of subgrade effectively. Besides, the settlement of the subgrade decreases with the increase of the thickness of crust layer. Moreover, with the increase of time, the uneven settlement of the pavement increases gradually. And when the time is up to a certain degree, the uneven settlement tends to be stable.

Abstract: In order to quantitatively evaluate the objective security of intersection in mountainous area, a danger index model was built after analyzing the factors of two-lane highway‘s intersection in mountainous area. The model was based on the highway conditions of the intersection, the traffic conditions around the intersection and the environment of intersections. According to the weight of every index and the danger index, the model divided the objective security into four ranks. The relevant data of several typical intersections in Shanxi province are evaluated. The conclusion shows the model can evaluate the objective security about the two-lane highway’s intersection in mountainous area quickly and effectively.

Abstract: Continuously push forward the process of Chinese urbanization and industrialization , development of transport and contradictions urbanization and industrial activities between the increasingly prominent. Geological hazards along the highway with Disaster in the rate, the complexity of the causes of the disaster , affecting a wide range, breaking strength and other characteristics of road transport caused great adversely affected. Common highway geological disasters are mainly ground subsidence, landslides, landslides and collapses. Prevention of geological disasters in the road, it must be based on scientific analysis of case types, characteristics and scale of the disaster, and take appropriate preventive measures on this basis.