1 Geogrid reinforcement applications：
This process is applicable to the soft foundation treatment of municipal roads and highway projects, the reinforcement of pavement, embankment and filling slope, and the treatment of landslide and collapse
Repair and other works.
2 Geogrid reinforcement for roads main application standards and specifications：
2.0.1 technical code for application of geosynthetics (GB50290-1998)
2.0.2 geosynthetics plastic geogrid (GB / t17689-2008)
2.0.3 geosynthetics geogrid for Traffic Engineering (JT / t480-2002)
3 construction preparation
3.1 technical preparation
3.1.1 carefully study the relevant requirements of Geogrid reinforcement for roads construction drawings and various construction specifications before commencement.
3.1.2 measure the subgrade elevation before laying the geogrid.
3.2 material preparation
The geogrid used for the reinforcement of embankment slope adopts two-way geogrid. The width of geogrid is not less than 3.0m and the tensile strength is
Not less than 30KN / m, elongation ≤ 10%.
The Geogrid of pile net composite foundation used for soft foundation reinforcement adopts two-way geogrid, which adopts high-strength polyester fiber, polyester and poly
Ethylene and other materials are used for soft foundation reinforcement. The tensile strength is determined according to the calculation, but generally not less than 80KN / m. The width of geogrid is ≥ 5.0m,
Elongation ≤ 10%
When the drainage consolidation method is adopted for construction, the geogrid can be unidirectional geogrid, and the tensile strength is determined according to the calculation, which is generally not less than
50KN/m。
Before the geogrid is laid, the performance of each batch of products shall be tested by the qualified product quality supervision and inspection center authorized by the state,
The detection frequency shall not be less than 3 groups, and the laying can be carried out only after it is qualified. The construction quality shall comply with the national standard technical code for application of geosynthetics
(GB50290-1998)。
4 construction operation process
4.1 process flow
4.2 survey setting out and site cleaning
4.2.1 measure and set out the construction site according to the construction specifications and design requirements.
The original ground shall be cleaned and rolled, and the base treatment is the same as that of general subgrade filling construction. The subgrade shall be carried out after the treatment is completed and the inspection is qualified
Layered filling.
4.2.2 when the filling height reaches the elevation of the designed Geogrid reinforcement for roads and geocell, the measurement shall be carried out on the qualified filling surface
Measure and set out, and determine the position of laying geogrid and geocell according to the design requirements.
4.3 construction method
4.3.1 laying shall be carried out within the measured range. The geogrid is laid flat on the subgrade, the outer edge is generally 0.1M away from the slope, and the laying width is
Set according to the design requirements.
4.3.2 folds are not allowed during laying, and they shall be tightened. After paving, fix it with U-shaped iron nails or bamboo nails.
Direct exposure to the sun for a long time.
4.3.4 when laying geogrid, the length of transverse lap and longitudinal lap shall meet the design requirements.
4.3.5 after the geogrid is paved, the filler shall be filled in time. When the filler is not paved, mechanical vehicles shall not walk on it.
4.3.6 plastic geogrid can be divided into longitudinal stress and transverse stress according to the design requirements. The laying of geogrid shall be in strict accordance with the design requirements
Laying is required by the design.
4.3.7 the dump truck dumps the filler along the edges of both sides of the reinforced material to form an access road for soil transportation, and tension the plastic grid. fill
The materials are not allowed to be directly unloaded on the plastic grid, but must be unloaded on the paved soil surface: the unloading height should be no more than 1m, and
Avoid insufficient local bearing capacity. The soil shall be paved immediately after unloading to avoid local subsidence. After the construction access road is filled, it is on both sides
Fill symmetrically to the center parallel to the central line of the embankment, and keep the filling construction surface in a “U” shape.
4.3.8 the first layer of fill on the plastic grid should be paved by light bulldozer or front loader, all vehicles and construction machinery
Only driving along the axis of the embankment is allowed.
4.3.9 the geogrid is overlapped 30cm longitudinally and 50cm transversely.
4.3.10 the longitudinal and transverse surfaces shall be fixed with L-shaped nails.
On the basis of nail anchorage, the lap joint is bound with 22 double strand iron wire, and the binding node spacing is 15cm.
4.3.12 the geogrid is fixed from the middle of each mesh.
5.1.1 the quality of raw materials shall be spot checked according to the specified frequency and standards, and protection shall be strengthened during construction to prevent pollution and damage.
5.1.2 the surface of the lower bearing layer of geosynthetics shall be leveled and compacted, and the hard protrusions on the surface shall be removed.
5.1.3 when laying geosynthetics, the direction with high strength shall be placed in the main stress direction of embankment. When there are special requirements in the design
Laying according to design.
5.1.4 after the geosynthetics are paved, the folded section shall be paved back according to the design requirements and covered with sand in time.
5.1.5 it is strictly prohibited to roll or walk on Geosynthetics directly by rolling and transportation equipment.
5.1.6 the overlapping and anchoring width shall meet the requirements.
5.1.7 the original ground drainage shall form a 4% crown.
5.1.8 laying geosynthetics belongs to concealed works. Quality inspection personnel shall be responsible for on-site monitoring and inspection of concealed works during construction
Record and report to the supervisor for signature before the construction of the next process.
6 quality precautions
6.1 during the laying of Geogrid reinforcement for roads, the direction with high strength shall be placed perpendicular to the axis of embankment.
6.2 the surface of the soil layer where Geogrid reinforcement for roads materials are laid shall be flat, and there shall be no hard protrusions such as debris and block stones on the surface. After paving, it shall
When filling, the filler shall be filled to avoid direct exposure to the sun for a long time. Generally, the interval shall not exceed 48h.
6.3 all vehicles and construction machinery are only allowed to travel along the axis of the embankment after the geogrid is paved with fill.
6.4 the geogrid shall not be damaged during construction to ensure the project quality.
6.5 during paving, it shall be straightened and smooth without distortion and fold.
6.6 when laying between plastic gratings, the direction with high strength shall be placed perpendicular to the embankment axis.
6.7 the connection between plastic gratings shall be firm. The strength of the joint in the stress direction shall not be lower than the design tensile strength of the material, and
The overlapping strength shall not be less than 15cm.
6.8 the plastic grating shall be laid without wrinkles and shall be tensioned manually. If necessary, the plastic grating can be fixed by inserting nails and other measures
Fill surface.
6.9 the surface of the soil layer on which the plastic grid is laid shall be flat, and there shall be no convex objects such as debris and block stones on the surface; At a distance of 8 cm from the plastic grid layer
The maximum particle size of Embankment Filler in shall not be greater than 6 cm.
6.10 the filler shall be paved and rolled in layers, and the selected filler and its compactness shall meet the requirements specified in the design.
6.11 the first layer of fill on the plastic grid should be paved by light bulldozer or front loader, and all vehicles and construction machinery should be used only
It is allowed to drive along the axis of the embankment.
6.12 it is forbidden to directly roll all mechanical equipment on the grid surface.