Applied Mechanics and Materials Vols. 178-181

Abstract: Water is an important reason lead to the moisture damage on the asphalt pavements. In the paper, investigations and tests indicate that the poor permeability of the asphalt layer when the road opening to the traffic is a very common defect nowadays. The permeability would decrease under the hydraulic and air pressure resulted by moving vehicles, the water would directly penetrate the asphalt layer and accumulate at the interface betweens different layers. The precipitation water could also enter the pavement through the cracks and central separation belt, and accumulate as well, which lead to the development of moisture damage occurred at the bottom and upward subsequently. The intrude water also causes moisture failures in the base as well as the asphalt layer.

Abstract: Traditional methods of wheel-rail contact forces measurement all need strain gauges on wheel sets or rails. The shortcomings of strain gauges such as zero-drift, poor anti-interference property and instability of test system can’t meat wheel/rail force test requirements in high-speed railways. A method based on PVDF piezoelectric sensing technology is presented for the test of wheel/rail contact force. Firstly, on the basis of the theory of vehicle-track coupling dynamics and by means of simulation software ADAMS/Rail, a three-dimensional train-track simulation model is established. Secondly, the modes and characteristics of wheel/rail impact vibrations due to non-roundness of railway wheels are investigated in high-speed railway operation. The relationship between the range for acceptable roundness values and vehicle speed is determined. Finally, the view that it is of important significance to establish wheel/rail force real-time monitoring system is expanded, so that abnormal conditions caused by out-of-round wheels can be detected in time, to ensure high-speed railway traffic safety. The study is very important for enhancing the stability and economy signification of rail transmission.

Abstract: Rock bolting is one of the most common methods of rock reinforcement. To optimize bolt parameters for reasonably playing its properties under safe support condition, it’s a must to study the mechanical characteristics of roadway and bolt. This paper shows that anchor bolts at the top of the rise side has the maximum force, middle of the two sides minimal. Middle of two sides has the largest displacement, top and bottom smallest by using flac3d to simulate the force of special-shaped roadway under the support of anchor bolts, combined with field observance of anchor bolts force. Therefore, by optimizing anchor bolts supporting parameters, we can effectively control the deformation of surrounding rocks and improve the whole stability through strengthening support and changing partial anchor bolts supporting parameters.

Abstract: The quality of pavement damage investigation is a main factor that can affect the outcome of pavement performance evaluation. Thus, the investigation plays a key role in such evaluation. This research developed a new manual pavement damage investigation method by using modern measure technology and GPS positioning technology. According to this method, data has been saved in a computer and it can be used as pavement performance evaluation and design purpose directly. Therefore, the work efficiency will be improved dramatically by adopting this method.

Abstract: Highway high slope seismic stability is an urgent problem need to be solved, and the existing specifications can not meet the needs of engineering in design methods, construction measures and enforceability. Based on the earthquake failure mechanism of high slope, this paper analyzes the impact factors on highway high slope seismic stability, and puts forward earthquake preventive measures for high slope.

Abstract: The problem of composite grade are discussed on highway of long and steep grade, namely how to ascertain the values of grade, length of grade and the sequence of composite grade, when the whole section of grade is composed of some different grade. The rationality of grade length limit methods is argued certainly according to the percentage each grade. The diverse combined circumstance of gradient are contrast analyzed from the angles of dynamic quality and economical quality of vehicle operation, then the design methods of composite grades with best dynamic and economical quality of vehicle is put forward to ascertain the values of grade, length of grade and the sequence of composite grade. The best vertical combined project is put forward that the composite grade of larger and smaller is better than average grade, and it is better than the composite grade of smaller and larger also. The bigger proportion of length of smaller grade is, and the better composite grade is.

Abstract: Dowels are used in jointed plain concrete pavements to provide lateral load transfer across transverse joint through shear force, effective load transfer at lateral joints can reduces stresses in the slabs. Steel dowels are generally used in engineering practice, but corrosive substance such as carbon chloride ions ,dioxide can free access and easily dispersed along the length of the steel dowels, therefor rapid corrosion can occur which can lead to premature failure of the transverse joint. Glass fibre reinforced polymer (GFRP) dowels have been recently introduced as a possible solution to the corrosion problem posed by steel dowels. This paper given a comparison of the maximum shear forces of none eroded GFRP dowel at the joint face with the help of a three-dimensional finite-element model and investigated the performance of GFRP dowels under static and cyclic load. According to the experiment results, the larger-diameter GFRP dowels were found to perform the best in this study.

Abstract: In a jointed plain concrete pavements, the dowel bar system are used to provide lateral load transfer across transverse joint. Corrosion of commonly used steel dowel in engineering practice reduces their service life and costs considerable maintenance and repair spending for concrete pavements. The objective of this study focus primarily on the performance of none eroded GFRP dowel on LTE( load transfer efficiency) with the help of a three-dimensional finite-element model. The amount of LTE can be obtained directly from comparing the maximum deflection of the concrete slab and the level tensile stress under the concrete slab. According to the finite element results, the larger-diameter GFRP dowel are found to perform the best in this study.

Abstract: Based on MapGIS platform, using vc++ development tools and SQLServer database management system,a 3D visualization and monitoring and warning system for mountain area highway slope was developed in this paper.The system realized the remote real-time monitoring, inquiry, statistics analysis and forecast for displacement and rainfall data.the management and data analysis of drilling and cross-section data were also implemented using 2D GIS.A special 3D modeling module was developed to construct the 3D space model of surface,ground and underground,and in the same time, the function of 3D visualization analysis and inquire based on the the models was presented in this system.The system was used in a highway slop of west hunan and a good effect was obtained

Abstract: To detect the chemical composition and physic-mechanical properties of converter steel slag of Jigang Group Co., Ltd and evaluate its feasibility as aggregate of the bituminous mixture. Prepare three kinds of AC20 bituminous mixtures by all using the steel slag as aggregate, by partially using the steel slag as aggregate and by all using macadam as aggregate respectively, and analyze the physic-mechanical properties of such three kinds of bituminous mixtures. The test analysis results prove that the high-temperature stability, low-temperature crack resistance and fatigue property of the bituminous mixture with all steel slag as aggregate or partial steel slag as aggregate are superior to those of macadam mixture. Although its water stability is a little bad, it still can meet the specification requirements, and it is suggested to be used widely in the middle and lower surface layers of pavement structure layer.