In the urban road subgrade widening project, the geogrid reinforcement is mainly to arrange the geogrid in the soil layer by layer, and use the friction between the upper and lower surfaces and the soil to reduce the soil settlement on the upper and lower surfaces of the geogrid. Deformation, thereby increasing the friction between the soil and improving the ability of the soil to resist vertical deformation. The main principles are:
(1) The friction between the soil under the roadbed and the geogrid;
(2) The frictional force between the soil body in contact with the upper and lower surfaces of the geogrid makes the soil body work together, so that the load transmitted by the road surface is evenly transferred to the soil body below;
(3) The geogrid itself has better material mechanical properties and can provide greater tensile strength and resistance to deformation.
In short, the installation of geogrid reinforcement is mainly to increase the cohesion or friction between the geogrid and the soil and the soil itself to achieve the overall stability between the new and the old roadbed and reduce the settlement difference.
Setting geogrid reinforcement in the widened roadbed can reduce road settlement deformation. When the number of geogrids is increased or decreased, it has almost no impact on the settlement and deformation of existing urban roads, but it has a more obvious impact on the deformation of the widened roadbed. The greater the number of reinforced layers in the widened subgrade, the smaller the settlement of the widened subgrade, but when the number of paving layers exceeds a certain level, there is little difference in the control of settlement.
When the reinforcement technology is installed on the first to the fifth floor, the settlement of the new subgrade gradually decreases; when the fifth and sixth floors are reinforced with geogrids, there is no obvious difference in the settlement and displacement of the top of the subgrade. But it can stabilize the settlement and displacement of the top surface of the subgrade.
After analysis, the more the depth of the geogrid is laid, the settlement deformation of the roadbed gradually decreases; the deeper the laying depth is, the smaller the impact on the settlement deformation, but it has the effect of reducing the cracks on the road surface.