Flexible Pavement Above The Granule Base Shear Behavior Research In Low-volume Highway

Based on pavement structure type at home and abroad and the character of low accumulative equivalent axle in the low-volume highway, the flexible pavement structure above the Granule base is considered to be suitable for the low-volume highway.Because the thickness of the surfacing course of the flexible pavement structure above the Granule base is thin, it acts as a function effect. Correspondingly, the base course of the pavement structure undertakes mainly the effect of the traffic load. So the higher shearing stress exists in the base course. However, the shear strength of Granule materials is own inferior. To prevent shear failure, the checking of the shear stress is rather necessary. Firstly, under the standard axis load, the maximum shear stress of the Granule base can be acquired. Through comparing the maximum shear stress and the shear strength of the Granule material, the conclusion of checking calculation are got. Secondly, based on the granular mechanics, when the ratio of the shear stress and the normal stress is the biggest, the shear stress is considered to the most easily disruptive value of the kind of granular material. Through comparing the shear stress and the shear strength of the granular material, the conclusion of checking calculation are obtained. Based on the elastic layers system theory, Nomograph of the limiting shear stress's position and the limiting the shear stress of three layers systems are obtained; and the rule of biggest shearing stress along the asphalt pavement structure depth direction are analyzed.At last, combining with the example of the flexible pavement structure above the Granule base, the significance of the checking is further verified. The measure is proposed to solve the lack of the shear strength.