● Introduction
○ Geo-grid is a high-strength structural material which contains macromolecule polymer as main raw materials with addition of some anti-ultraviolet and anti-aging auxiliary agents and provides molecular structure realigned in vertical and horizontal direction by means of the workmanship control in the process of fabrication, including stretched single geo-grid (TGDG series) and stretched bidirectional geo-grid (TGSG series).
○ Stretched single geo-grid is a synthetic material used for strengthening and reinforcement of civil works, in which macromolecule polymer is adopted as main raw materials, some anti-ultraviolet and anti-aging auxiliary agents are added and orientation is made through deeply stretching, being characterized by high strength and low extension.
○ Stretched bidirectional geo-grid is a high-strength structural material, in which molecular structure is realigned in vertical and horizontal direction with high tensile strength in the process of fabrication.
● Performances
○ Provide the integrative structure and high strength for node
○ Provide high tensile yield strength and low elastic strain to ensure geo-grid has high tensile strength in the low elastic strain;
○ Ensure no deformation with good creep resistance under the continuous load for long time;
○ Provide high friction coefficient (approximately 0.8) and strong acting force for mud and sand, stone and concrete to prevent slippage;
○ Provide stable chemical property, corrosion resistance against such organic solvents as acid, alkali, salt solution or gasoline and diesel fuel;
○ Geo-grid can not be dissolved by water, free of cracking caused by environmental stress and damage from micro-organism
○ Light, convenient for transportation and construction, low maintenance fee;
○ Provide anti-aging and above 120 years’ service life under load.
● Application:
○ Reinforcement for subgrade of road and railway, protection for dome, prevention against soil and water loss, repair for collapse and landslide of slope, treatment for soft foundation of road, reinforcement for embankment foundation, reinforcement for retaining wall and abutment, works of landfill site and laying of pipeline.
● Model and technical parameters
○ Stretched single geo-grid:
|
Item
|
TGDG25
|
TGDG35
|
TGDG50
|
TGDG80
|
TGDG110
|
|
Mass in unit area g/m2
|
370±50
|
450±50
|
550±50
|
700±50
|
1100±50
|
|
Width m
|
1.0 or 2.0
|
○ Stretched bidirectional geo-grid:
|
Item
|
TGSG15-15
|
TGSG20-20
|
TGSG30-30
|
TGSG40-40
|
TGSG45-45
|
|
Mass in unit area g/m2
|
300±30
|
330±30
|
400±40
|
500±50
|
550±50
|
|
Width m
|
4.0
|
● Technical specification
○ Color and appearance quality: black, even color and luster, free of visual oil stain, damage and cracking;
○ Physics mechanical property:
○ Stretched single PP (polypropylene)geo-grid
|
Item
|
TGDG25
|
TGDG35
|
TGDG50
|
TGDG80
|
TGDG110
|
|
Tensile yield per linear meter, KN/m ≥
|
25
|
35
|
50
|
80
|
110
|
|
Yield elongation, % ≤
|
10
|
|
Drawing in 2% elongation, KN/m ≥
|
7
|
10
|
12
|
26
|
32
|
|
Drawing in 5% elongation, KN/m ≥
|
14
|
20
|
28
|
48
|
64
|
○ Stretched single HDPE (high density polyethylene)geo-grid
|
Item
|
TGDG25
|
TGDG35
|
TGDG50
|
TGDG80
|
TGDG110
|
|
Tensile yield per linear meter, KN/m ≥
|
25
|
35
|
50
|
80
|
110
|
|
Yield elongation, % ≤
|
12
|
|
Drawing in 2% elongation, KN/m ≥
|
6
|
9
|
10
|
23
|
30
|
|
Drawing in 5% elongation, KN/m ≥
|
12
|
18
|
25
|
44
|
60
|
○ Stretched bidirectional PP (polypropylene) geo-grid
|
Item
|
TGSG15-15
|
TGSG20-20
|
TGSG30-30
|
TGSG40-40
|
TGSG45-45
|
|
Vertical tensile yield per linear meter, KN/m ≥
|
15
|
20
|
30
|
40
|
45
|
|
Horizontal tensile yield per linear meter, KN/m ≥
|
15
|
20
|
30
|
40
|
45
|
|
Vertical yield elongation, % ≤
|
13
|
|
Horizontal yield elongation, % ≤
|
16
|
|
Drawing in 2% vertical elongation, KN/m ≥
|
5
|
8
|
11
|
13
|
16
|
|
Drawing in 2% horizontal elongation, KN/m ≥
|
7
|
10
|
13
|
15
|
20
|
|
Drawing in 5% vertical elongation, KN/m ≥
|
8
|
10
|
15
|
16
|
25
|
|
Drawing in 5% horizontal elongation, KN/m ≥
|
10
|
13
|
15
|
20
|
22
|
● Notes:
○ As generally KAILE geo-grid is long 50m/piece, or customized.
○ HDPE (high density polyethylene)geo-grid is characterized by favorable anti-low temperature and widely used for high and cold zone.
○ PP (polypropylene) geo-grid is characterized by favorable anti-cracking caused by environmental stress and used at -23℃~70℃.
● Operation manual
● Reinforced foundation:
Reinforced foundation means reinforcement for soft soil to increase bearing capacity of foundation or reduce settlement. Such reinforcement includes the following three types according to site construction condition and importance of structures:
○ Raft foundation: provide wide and flat ground, not required for washing for toe of slope; prohibit construction vehicle from driving directly on soft foundation; lay geo-grid onto the surface of soft foundation directly to form a rafted bedding course with 0.5-1.0m thickness; lay 1-3 course (s) of geo-grid;
○ Bedding: If structures need high resistance against settlement and deformation or a geological duricrust produces in the superficial layer of ground, fix geo-grid reinforcement course into concealed bed. The bedding thickness is 0.5-1.0m. Lay 1-3 course (s) of geo-grid;
○ Piling: For the important structures, with high foundation stress, place the geo-grid bedding course onto the surface of composite foundation produced by pile and bedding sand to minimize uneven settlement and improve stability for foundation.
● Reinforced claybank
Reinforced claybank is filled and built on stable foundation. If construction site is so limited that it is required to set claybank at the steep slope, lay geo-grid reinforcement course layer by layer into the slope body along bank or into the whole claybank to form reinforced claybank or slope. Such reinforcement includes the two types as follows:
○ 1 Sloping: If the height of claybank is not great (8m below) and the slope gradient is small (1:1), incline the side slope and then horizontally lay geo-grid layer by layer along the slope height, besides the horizontal length is equivalent or not, identified by the designer, as generally 2-3m for the equivalent length; the vertical space between grid course is 0.3-0.5m with equivalent length, or designed by slope height if no equivalent length. Wrap and wind the end of geo-grid at the dome and then take planting or protection for the dome.
○ 2 Stepping: If claybank is higher (8m above) and the slope height is greater, make stepping for the side slope of claybank.
● Reinforced retaining wall
Reinforced retaining wall is built on the stable foundation. Geo-grid reinforcement for retaining wall has no differences from the common strip in reinforcement principle, but the geo-grid can provide better effect in reinforcement. The geo-strip reinforcement for retaining wall causes unreinforced passage between nodes to connect the upper part with the lower part, instead geo-grid reinforcement produces less deformation for the side of retaining wall to facilitate connection with wall and ensure good laying quality.
○ Masonry-block wall: Build wall with prefabricated concrete block. The size of prefabricated block is 0.25×0.3×0.5m or 0.25×0.3×1.0m without breakage during the manual handling. Use pin to connect the upper masonry block with the lower masonry block. Pass geo-grid through masonry block or directly fix it between the upper and lower masonry blocks;
○ “L”-shaped panel wall: Use “L”-shaped prefabricated plate with reinforced concrete to build wall to protect template and wall. It is allowable that geo-grid may not connect the wall, but it is only to wrap and wind the end of wall, and then make filling with earth.
● Reinforced pavement:
For reinforcement of pavement, separation function and side pressure of geo-grid is mainly used to repair pavement cracks or reduce rut depth of pavement and prolong pavement maintenance period, or to thin substrate and reduce pavement thickness under the equivalent load. It is unnecessary for reinforced pavement to require special structure. As designed lay geo-grid on the top of substrate (to reduce rut depth) or on the bottom of substrate (to reduce pavement cracks), and lay geo-grid in other areas similarly to structure of unreinforced pavement.