In the construction of high or low foundations, according to the unique characteristics of geogrids, there are multiple choices, and the application of the high-filled subgrade of the expressway has been recognized by the majority of construction units.
Before the construction of the subgrade is filled, the surface of the subgrade needs to be cleaned, and the weeds, humus, debris, soft soil and other impurities on the surface of the subgrade should be effectively cleaned. After the cleaning is completed, the entire paving site should be leveled . According to the basic principles of roadbed construction, the roadbed is vibrated and compacted to ensure that the bearing capacity of the roadbed meets the requirements.
The slope of the original ground is steep, when the slope is greater than 1: 5, the slope surface needs to be dug stepped, the width of the step is controlled to be more than 2m, and the slope must be set within 2% to 4%, and the step needs to be small The tamping machine performs tamping.
Before laying the geogrid, it is necessary to ensure that the flatness of the laying base meets the requirements. Generally, the flatness should be controlled within 15cm. The laying of the base is strictly prohibited from crushed stones and large-sized stones. Lay a full-section geogrid on the leveled underlayer and mark the laying range of the geogrid with wooden piles. In addition, when paving the geogrid, it needs to be straightened, the surface of the grid is flat, and it needs to be close to the lower bearing layer. The length of the lap of the two adjacent geogrids should be controlled within a reasonable range, and the general lap width should be controlled within 300 ~ 600mm. The lap width of the upper and lower layers of the double-layer geogrid needs to be staggered by a certain distance, and the gap between the upper and lower layers is generally staggered It should be no less than 50cm and need to be anchored with U-shaped nails. The U-shaped nails are arranged according to the plum blossom shape, and the spacing should not be greater than 1m. At the same time, the distance between the two sides of the geogrid and the edge of the embankment is maintained at 1.5m, and for the integrity of the grid and the soil, the grid needs to be folded back on the compacted filling level and back to the exposed geotechnical The grille needs to be covered with soil. In addition, when the geosynthetic material is damaged during construction, the damaged part of the geogrid needs to be replaced in time.