Applied Mechanics and Materials Vols. 505-506

Abstract: The plate-chair type retaining structure, which developed from h type anti-slide pile, has the characteristics of high stiffness and small deformations, and is suitable for subgrade retaining engineering on high slopes. The difficulty is that the landslide thrust distribution is not clear and the action of soil between the front and back row piles is not definite. First, a theoretical method of calculating the earth pressure acting on the structure is presented based on analyzing its carrying mechanism. Then an example is analyzed using the method. Finally, on the base of constructing a three-dimensional numerical simulation model of soil-structure interaction using ABAQUS, a validation and comparison between the theoretical calculation and numerical simulation is carried out. The result shows that the method is simple, safer, suitable for designing and can be used in the similar engineering.

Abstract: The biaxial test on ballastless track subgrade material of surface layer and bottom layer of subgrade was established using the particle flow code(PFC). Based on the micro parameter gotten from the biaxial test, a two-dimensional discrete element model of slab Ballastless Track subgrade is modeled. The dynamic response under dynamic load was calculated. A comparison of simulation results and the field measured data shows goodness of fit which provides a new way of simulation on dynamic response of high speed railway subgrade.

Abstract: In order to analyze the characteristics of high modulus asphalt mixture dynamic modulus, Universal Testing Machine (UTM-25) was used for dynamic modulus test of three kinds of mixtures, which were PR Module modified asphalt mixture and PR PLAST.S modified asphalt mixture and virgin asphalt mixture, to investigate dynamic modulus and phase angle at different temperatures and frequencies. The results indicate that: the dynamic modulus order of the three asphalt mixtures is PR MODULE > PR PLAST.S > Virgin. PR MODULE asphalt mixture dynamic modulus is much larger than the other two.

Abstract: To reasonably design the layout scheme of CFG piles treatment in highway soft foundation settlement, the influence factors of CFG piles treatment were analyzed and evaluated, based on the FEM model. According to the results, the space between CFG piles has the greatest influence. With the increase of pile spacing, the surface settlement of subgrade increases correspondingly. The settlement differentials of each CFG piles layout scheme are also put forward as a reference to highway soft ground settlement control.

Abstract: Based on basic principle of detection using impact-echo method, in combination with urgent demand of grouting quality inspection in ducts inside post tensioning type prefabricated box girder in bridge engineering, impact-echo method has been used for non-destructive detection of grouting compactness in pre-stressed ducts inside prefabricated box girder. Verification by beating away measuring points shows that the impact-echo method can accurately locate metal corrugated pipes and qualitatively judge grouting compactness inside prefabricated box girder ducts, to allow effective inspection of grouting quality in strands of pre-stressed ducts.

Abstract: Control of differential settlement of widened subgrade is one of key pints for the quality control of expressway reconstruction and extension projects and a focus for many scholars. In the paper, the analysis model of the pavement structure stress is built based on character and design parameters of the subgrade and pavement of Tianjin-Binhai Expressway. The control standards for the subgrade and pavements differential settlement of Tianjin-Binhai Expressway are confirmed through analyzing the pavements mechanical response under different differential settlements and treatment measures are taken according to classification of different differential settlements to control the final settlement amount within the preset range, which provides references for renovation and extension projects in future.

Abstract: Conduct experimental study on low temperature performance about asphalt concrete with 6mm basalt fiber and without basalt, 6mm fibers whose dosage is 0.12%0.15% and 0.17%, test method is the indirect tensile test,test temperature is-10±0.5°C. The results show that basalt fiber improved the strength and failure strain of asphalt concrete in low temperature damage, reduced the failure stiffness,in which the maximum increased value of breaking strength is 3.41%, the maximum increased value of failure strain is 38.83%,and the maximum reduced value of failure stiffness is 25.52%,obviously improved low temperature cracking resistance of asphalt concrete;for low temperature performance, the optimum amount of value about 6mm basalt fiber is 0.15% .

Abstract: Conduct experimental study on high temperature performance about asphalt concrete with 6mm basalt fiber and ordinary asphalt concrete, 6mm fibers whose dosage is 0.12%0.15% and 0.17%, test method is high temperature rut test, test temperature is 60°C. The results show that basalt fiber can improve the high temperature properties of asphalt concrete substrate, in which basalt fiber asphalt concrete maximum dynamic stability value is almost 1.27 times that of ordinary asphalt concrete, permanent deformation is 34.02% lower than that of the ordinary asphalt concrete, improved the shear performance of asphalt concrete;for high temperature performance, the optimum amount of value about 6mm basalt fiber is 0.15% .

Abstract: In this paper, in order to improve the high speed railway sustainable competitive advantage as the research objective, systematic analysis of the high-speed railway to obtain sustainable competitive advantage evaluation index, including high-speed railway traffic function advantage, competitive advantage, advantage of positive externality, the Delphi method is used to scientific empowerment of these factors, by constructing fuzzy comprehensive evaluation model, the research conclusion is highway and air passenger is higher than that in high speed railway of competitive advantage