The development of geogrids is rapid, and the application in reinforced earth structures is also increasingly widespread. The special mesh structure of geogrids can bite the soil particles together to form an interlocking structure. The pull-out resistance of geogrids in filling It comes from the friction between the surface of the vertical and horizontal ribs and the soil, and from the passive resistance of the soil to the grid rib caused by the interlocking effect. The geogrid reinforced soil structure is a flexible structure that adapts to structural deformation The ability and earthquake resistance are strong, and it has good social benefits, economic benefits and environmental benefits such as saving investment, saving land, protecting natural ecology, etc. Therefore, geogrids are often more effective than many traditional methods in handling many geotechnical engineering problems. To be effective and appropriate.
In the past, the fillers of reinforced earth generally used sand or gravel materials with good water permeability, high strength and small deformation. However, due to the reasons of filler yard, land resources, ecological environment protection, etc., many reinforced soil projects have to be used. Expansive soils with special properties are excavated and discarded as fill. In recent years, there have been many water conservancy channels, highways, and railways in China that have successfully used geogrids to reinforce dikes for expansive soils.
The reinforcement effect of the geogrid is mainly to reinforce the restriction effect of the original ground on the fill by layering the reinforced material layered at the junction of the fill and excavation, and at the same time form a structure with a gradual transition of support stiffness in the longitudinal direction, making the top of the subgrade The surface settlement tends to be uniform, and the length of the non-uniform settlement deformation is extended to achieve the purpose of reducing the slope change of the longitudinal slope of the road surface. The reinforcement effect of the geogrid on the subgrade section of the horizontal filling and excavation junction is to strengthen the stability of the filling soil. On the premise of preventing landslides, further strengthening the original ground to fill is an aspect of settlement control.
The uneven settlement will also cause the constraint of highway soil, avoid local settlement and sliding of the fill at the top of the roadbed at a limited depth, reduce the tensile stress and shear stress on the roadbed top surface and pavement structure, so as to avoid the roadbed top surface and pavement structure from cracking Or slip; second, when the width of the filling soil is large or the original ground of the filling part is flat, the effect is similar to the treatment of the vertical (route direction) filling and excavation junction.
In addition, when selecting a geogrid, in addition to its performance indicators should comply with the rules in the above table, special attention should also be paid to ensure that its width is not less than 1.5m, to satisfy its use as a cross-sectional area to control the anti-crack interlayer. Fully dissipate the crack energy; together, the mesh size should be 0.5 ~ 1.0 times the larger particle size of the asphalt surface material on it, which helps to reach the shear adhesiveness and promote the interlocking and restraint of the aggregate.