During the construction process of the road roller, the engineering properties of the roadbed have a great influence on the rolling of the road surface. In general, as the stiffness of the subgrade increases, the pavement slab is more difficult to break, and the longitudinal and transverse cracks in the slab are different when the stiffness is different. When the stiffness of the subgrade is high, transverse cracks are easy to form, and when the stiffness is low, longitudinal cracks are easy to form.
On the whole, the base layer and the pavement are in a state of vertical and horizontal bending, and the maximum vertical displacement value and distribution are basically the same as those of the pavement. The stress on the top surface of the base is mainly compressive stress, and the stress is mainly tensile stress. Therefore, there are many stress centers, which are generally distributed below the load point or along the edges and corners of the concrete pavement, and are mostly tensile stress areas and compressive stress areas alternately. This is the manifestation of the stress concentration in the base layer caused by the size effect of the concrete pavement slab under impact load.
With the development of impact rollers, the deformation characteristics of road slabs are also changing. During the impact crushing process, the maximum deformation point is always at the location of the impact load. Comparing the three impact load action points in each impact construction route, the vertical deformation is the smallest when the impact load acts on the slab, and the vertical deformation is similar when the impact load acts on the edge of the slab.
After the impact of a single impact point, although the deformation recovers quickly, it can be seen from the straight line of the deformation distribution of the pavement panel after the impact of the next impact point that the deformation is not completely recovered, that is, the deformation of the concrete pavement panel has a certain plastic deformation.
Similar to the deformation characteristics, the force is applied at the moment of the impact load, but the large stress decreases rapidly. The stress distribution is consistent with the longitudinal and transverse bending deformation of the plate. At the position where the impact wheel acts, the surface is mainly under compression, and there are different degrees of tension around the action point. At the bottom of the plate, there is a tensile stress zone below the impact point of the impact wheel, and a local stress zone around the boundary. The calculation results of the single-impact rolled pavement panel show that there are different degrees of plastic failure under various working conditions.
The working principle of our road roller is to drag the tractor forward to impact the road surface. On the one hand, due to the non-circular section characteristics of the compaction wheel, the center of mass will move up and down during the movement process. Through the displacement and transformation of kinetic energy and potential energy, concentrated impact energy is generated on the ground, and then one violent impact on the ground is generated. , and then the impact wheel itself produces a traditional rolling action on the soil, which in turn produces a greater compaction effect than traditional vibratory compaction machinery.
