Visual intervention has a significant influence on drivers’ behaviour, which may cause the redistribution of wheel tracks, relieving the stress from the concentration of axial loads so that the rut...

Using the visual intervention influence of pavement marking for rutting mitigation – Part II: visual intervention timing based on the finite element simulation

Aimed at the characteristics of aeolian sand under rapid construction conditions in desert geotechnical engineering, a series of the true triaxial undrained test were carried out on the GDS apparatus. The 3D deformation, failure, and other characteristics of the dense sand are obtained. Under the condition of same , the state transition point where the void water pressure changes from increasing to decreasing appears earlier and leads to enhanced dilatancy with the increase of b, which means the enhanced dilatancy of dense sand caused the increase in strength. The results of the same b shows that the void water pressure generally indicates a decrease at low confining pressure and an increase at high confining pressure, indicating that the aeolian sand shows dilatancy at low confining pressure and contraction at high confining pressure. The state transition point increases with the increase of , but all points tend to the same critical state line and state transition line. When b = 0, the critical state line is q = 1.57 , and the state transition line is q = 1.23 . When b = 1, the critical state line is q = 1.24 , and the state transition line is q = 1.04 . The results at same b obtained the unified critical state line and the state transition line. Therefore, the true triaxial test can obtain the unified relationship of void ratio, and b, which overcomes the fact that the existing test cannot consider the influence of b. The test results provide a basis data for the design, construction, and maintenance of geotechnical engineering in Tengger Desert.

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The Undrained Characteristics of Tengger Desert Sand from True Triaxial Testing

In order to study the dynamic response of the new type of semi-rigid asphalt pavement structure under different speed and continuous variable speed of vehicle,the 3Dfinite element model is built by ABAQUS based on the elastic layered system theory,the dynamic modulus parameters of pavement materials are utilized,and the subroutine UTRACLOAD and DSLOAD are compiled.In addition,mechanical responses of pavement structure calculated by static parameters are compared.And difference of mechanical performance indexes between new semi-rigid and the traditional pavement structure are also analysed.The results show that the vehicle speed has few effects on dynamic responses of pavement structure.Compared to the calculations by static modulus,strain of semi-rigid base layer is reduced and shear stress of asphalt surface course is increased when dynamic modulus is used.Furthermore,the new type of semi-rigid pavement structure can effectively reduce the rutting probability of intersections and improve its resistance to permanent deformation.

Liu Ning

Papers

Mechanical Analysis on the New Type of Semi-Rigid Asphalt Pavement Structure Based on Dynamic Parameters