Asisten Andal untuk Penguatan Permukaan Jalan - Geogrid Serat Kaca

Eight Steps of Geogrid in Subgrade Construction

1：Level roadbed

First, accurately mark the roadbed slope line. To ensure the roadbed width, add 0.5m to each side. After leveling the well-dried base soil, compact it with a 25T vibratory roller for two static passes, then with a 50T vibratory roller for four passes. Manual assistance is used to level uneven areas for geogrid.

2：Lay the sand and compact it

Lay a 0.3m thick layer of medium (coarse) sand, then level it with a combination of manual and mechanical methods, followed by two passes of static compaction with a 25T vibratory roller.

3：Lay the first layer of geogrid

Lay the first layer of it. When laying the geogrid, the bottom surface should be flat and compact. It generally laid flat, stretched straight, without overlapping, curling, or twisting. The adjacent two geogrid sheets need to overlap by 0.2m, and along the transverse direction of the subgrade, every 1 meter of the overlapped part of the geogrid should be connected by inserting No. 8 wire. Additionally, on the laid level, U-shaped nails should be used to fix it to the ground at intervals of 1.5-2m.

4：Lay the second layer of sand

After the first layer of geogrid is laid, the second layer of medium (coarse) sand with a thickness of 0.2m begins to be filled. The method is as follows: trucks transport the sand to the construction site and unload it on one side of the subgrade. Then, a bulldozer pushes the sand forward. First, fill 0.1m within a 2-meter range on both sides of the subgrade. Then, fold the first layer of geogrid upward and fill another 0.1m of medium (coarse) sand on top. It is strictly prohibit to fill from both sides towards the middle and to advance in this manner. Additionally, it forbids for various machinery to operate or pass on the geogrid that has not been filled with medium (coarse) sand. This ensures the geogrid remains flat, without bulging or wrinkling. Once leveling is confirmed to be accurate, a 25T vibratory roller should perform two static passes.

5：Lay the second layer

The construction method of the second layer of geogrid is the same as that of the first layer. Finally, 0.3m of medium (coarse) sand is filled, with the filling method being the same as the first layer. After compaction with a 25T roller for two passes, the reinforcement treatment of the subgrade base is completed.

6：Third layer of gravel and earthwork construction

After the (coarse) sand compacted in the third layer, two geogrids laid along the longitudinal direction of the line on both sides of the slope, with an overlap of 0.16m, and connected using the same method. Then, earthwork construction operations begin. When laying geogrids for slope protection, the edge line of each layer’s measured. On each side, after slope finishing, the geogrid buried 0.10m into the slope.

7：Lay slope geogrid

For the slope geogrid, a layer of geogrid should be laid on both sides every time two layers of soil are filled, i.e., when the thickness reaches 0.8m, and this process should continue until the geogrid is laid under the soil on the road shoulder surface.

8：Renovation

After the subgrade filled, slope finishing carried out promptly, and dry-laid stone protection should implemented at the toe of the slope. For this section of subgrade, in addition to widening by 0.3m on each side, a settlement allowance of 1.5%reserved.