Applied Mechanics and Materials Vols. 178-181

Abstract: Focusing on the severity of asphalt concrete pavement crack, the optimization analyzing finite element model(FEM) of typical asphalt overlay pavement was developed to address reflective cracking, in which the analysis of traffic-loading response were concentrated on the stress-intensive areas close to the joints or cracks. The FE sensitive analysis, evaluating the influence of pavement construction parameters, including modulus and thickness of pavement courses, is useful to establish comprehensive model of overlay pavement construction.

Abstract: LPD’s (lighting power density) definition, calculation method, standard value, influence factors and ways to reduce it are talked in this article. The aim is to take measures to reduce LPD properly. LPD should be less than standard value while guaranteeing traffic safety, average and uniformity road surface luminance. Then a road lighting system of energy-saving should be built as soon as possible.

Abstract: The site location has the crucial influence on the success of high-speed railway station area. Based on the site location type of high-speed railway station, this article analyzes the characteristics different types as a case of the Beijing-Shanghai high-speed rail stations. At last it puts forwards that the accessibility, demands for land and urban coordination are the main factors affecting the station location from both internal and external factors of the site location of high-speed railway station.

Abstract: Traffic safety in rural and urban areas is a serious public issue worldwide. In this paper, the weighted hazard index (WHI) was adopted to describe risk distributions in rural and urban areas. At the beginning, the WHI analysis results were shown in the GIS-based maps and the visual display of the hazardous segments was illustrated by ArcGIS software, which would help policymakers to assume more targeted improvement measures. Then logistic regression is introduced to assess the difference of incidence of total crashes and incidence of the fatal/injure crashes between urban and rural areas. Based on the estimation results of logistic regression analysis, the ADT (average daily traffic) and length of segments have more evident impact on the two risk factors, namely the incidence of total crashes and incidence of fatal/injure crashes. Furthermore, the differences between rural and urban areas are obvious in total crashes and fatal/injure crashes and more specifically they are all lower in rural areas with other attributes being fixed.

Abstract: The cement-fly ash-gravel (CFG)pile composite foundation played an important role in increasing the soft soil foundation strength and stability, and decreasing the foundation settlement etc, because that the pile strength potentiality could be fully developed and soils bearing capacity also could be fully utilized. The analysis of interaction rules among flexible embankment, CFG pile, soils, and cushion was the key factor to keep the CFG pile composite foundation stability. Three centrifugal model tests with different CFG pile spacing were conducted to research the effect of pile spacing on the CFG pile composite foundation stability, and the surrounding soils press, pile top press, pile strain etc were measured. It was shown that the embankment instability modes were different with CFG pile spacing. CFG pile composite foundation stability was affected by pile spacing, pile quality, and embankment height etc. Instability of CFG pile composite foundation was complicated, but not only for pile or soil destroyed.

Abstract: The elastic modulus of graded gravel material has a paricular characteristics of nonliner. The objective of this study is to discusses the performance of graded gravel roadbase in freeway pavement using KENLAYER computer program. Asphalt Institute (AI) and Shell design methods have been considered using equivalent standard axle load (ESAL) and spectrum of axle methods of incorporating traffic for the design period. Design life in years is determined using fatigue cracking models and rutting models in KENLAYER computer program, which is feasible in the life forecast of graded gravel roadbase. It is beneficial to graded gravel roadbase′s popularization and application in freeway pavement.

Abstract: Based on the large number of field surveys and long-term monitoring data of Hongceng, Hongliu and MengliuDong monitoring points, the wind-sand flow movement characteristics along the railway in Gobi area was analyzed. The shielding effect of the wind-break wall was evaluated by the methods of numerical simulation and field test. Conclusions drawn as followings: the wind-sand flow movement in Gobi area is characterized by stable of direction, seasonal, high-velocity,long-term,and shorting of starting-up time and moresand content. Numerical simulation shows that the wind flow form a large vortex region on the leeward side of wall, the flow field elements occurs significant changes. Both field test data and numerical simulations indicated that 3.0m height of wind-break wall meet the requirement of shielding wind-sand flow.

Abstract: Based on the geometry irregularity of pavement, an expression of the traffic load was put forward. The influence law of design parameters of each part of highway and pavement geometry irregularity on vertical deformation of highway was discussed by the three-dimension finite element numerical analysis. The research shows that the vertical deformation range of highway under the action of traffic load is generally semi-circular; the influence of surface stiffness on vertical deformation is different in different horizontal positions of surface; the influence of subgrade stiffness and foundation stiffness on vertical deformation is remarkable, but that of course stiffness is small; the rational matching of all parts of highway can effectively reduce the vertical deformation; with the increase of geometric irregularity index, the vertical deformation increases significantly.

Abstract: The plate-stone berm is an active cooling foundation to resist thaw. The Qinghai-Tibet Railway have been widely adopted the plate-stone berm to maintain the safety and stability of roadbed. Structure of the plate-stone berm have great effect on the safety of anti-thawing of roadbed. Different structure in one engineering measure cause different effect. Relying on the experimental segment in the region of Naquhe of Qinghai-Tibet railway (between DK1561+975～DK1562+530),the paper study the most safe anti-thawing structure by numerical analysis: The sunlit side height of plate-stone berm(dia. 20cm) is 1.1m, the sunless side is 1m. The sunlit/sunless side width is 6m/4m. The result is similar to practical test, which show that this method can use into engineering analysis.

Abstract: In recent years, domestic superelevation embankment common occurance, This paper uses the finite element strength reduction method, analyzing the stability about high embankment and high embankment multilayer under multilayer load with large-scale finite element analysis software named ANSYS, it is researched on the law of the infuence on multilayer slope load to the the different gradient high embankment stability.