PP gratingis a major geosynthetic material. High strength reinforced geotextile strips are made by special treatment of high-strength steel wire or other fibers with polyethylene or polypropylene and the addition of other additives, which are extruded to form a composite high-strength tensile strip with rough embossing on the surface.
The laying surface of PP grating should be relatively flat. After the acceptance of the laying layer, in order to prevent longitudinal tilting, white lines or hanging lines should be drawn on the laying layer according to the width to start laying. Then, U-shaped nails should be used to fix the end of the grating, with 4 nails per meter of width fixed at a uniform distance. After fixing the end of the grid, use a laying machine or manual labor to slowly pull the grid forward and straighten it every 10 meters until one roll of grid is laid, and then lay the next roll. The operation is the same as before.
The length of the section to be laid is based on the roll length. After the section length of the grid is fully laid, the laying quality should be checked once again, and then the next section should be laid. When laying the next section, the grid and the grid should be stacked with a net distance as the overlapping length, and fixed with binding wires before continuing to lay the section in the forward direction. Similarly, the operational requirements are the same as before.
When PP geogrid is applied to soft foundation treatment, the planned strength of the geogrid should also be confirmed based on the height of the roadbed filling, while confirming the orientation and number of layers of the geogrid based on geological conditions. When the filling height is greater than 4 meters, the PP grid can meet the requirements of industry standards, and the ultimate tensile force in both vertical and horizontal directions must also meet the standards. When the filling height is between 4 meters, the ultimate longitudinal and transverse tensile force of the geogrid shall not be less than 40kN/m. When the filling height is less than 3 meters, the ultimate tensile force in both vertical and horizontal directions of the geogrid should not be less than 50 kN/m, and the elongation should be less than 4%. It is recommended to use PP geogrid for roadbed filling and excavation.
When used for widening the joint of old and new roads, for roadbed with a filling height greater than 3 meters, a steel plastic composite grid shall be laid at a distance of 20 cm from the top of the roadbed. Steel plastic composite grids with a longitudinal straight road direction tensile force greater than or equal to 60kN/m and a transverse parallel road direction tensile force greater than or equal to 20kN/m shall be selected.