Geotextile paving facilities constructiion procedures and processes

Geotextile paving facilities construction procedures and processes

 

1. Storage, transportation, and handling of geotextiles
Geotextile rolls should be protected from damage before installation and unfolding. Geotextile rolls should be stacked in a flat and waterlogged area, with a height not exceeding four rolls, and the identification plate of the roll should be visible. Geotextile rolls must be covered with opaque material to prevent UV aging. During storage, it is important to maintain the integrity of labels and information.
During transportation (including on-site transportation from material storage to work), geotextile rolls must be protected from damage.
Geotextile rolls that have been physically damaged must be repaired. Geotextiles that are severely worn cannot be used. Any geotextile that comes into contact with leaked chemical reagents is not allowed to be used in this project.

2. The laying method of geotextile:
2.1 Manual rolling and laying; The fabric surface should be flat and leave appropriate deformation allowance.
The installation of long or short filament geotextiles usually involves several methods such as overlap, stitching, and welding. The width of stitching and welding is generally above 0.1m, and the overlap width is generally above 0.2m. Geotextiles that may be exposed for a long time should be welded or sewn together.
2.3 Suturing of Geotextiles
All stitching must be continuous (for example, spot stitching is not allowed). Before overlapping, the geotextile must overlap by at least 150mm. The minimum needle distance from the edge of the fabric (exposed edge of the material) should be at least 25mm.
The joint of the sewn geotextile includes one row of thread locking chain joint method. The thread used for stitching should be a resin material with a minimum tension of over 60N, and have resistance to chemical corrosion and UV radiation equivalent or exceeding that of geotextiles.
Any "missing needle" on the sewn geotextile must be re sewn in the affected area.
Corresponding measures must be taken to prevent soil, particulate matter, or foreign substances from entering the geotextile layer after installation.
The overlap of fabrics can be divided into natural overlap, seam joint, or welding according to the terrain and usage function.

2.4 During construction, the geotextile on top of the geotextile membrane is naturally overlapped, and the geotextile on the upper layer of the geotextile membrane is seam welded or hot air welded. Hot air welding is the first method of connecting long filament geotextiles, which involves using a hot air gun to instantly heat the connection between two pieces of fabric at high temperatures, causing some of them to reach a melting state, and immediately applying a certain amount of external force to firmly bond them together. In humid (rainy and snowy) weather where hot adhesive bonding is not possible, geotextiles should adopt another method - the stitching method, which is to use a dedicated sewing machine for double thread stitching and connection, and use anti chemical ultraviolet stitching thread.
The minimum width for stitching is 10cm, the minimum width for natural overlap is 20cm, and the minimum width for hot air welding is 20cm.
2.5 For stitching, the quality of the suture should be the same as that of the geotextile, and the suture should be made of materials with stronger resistance to chemical damage and UV light irradiation.
2.6 After the geotextile is laid and approved by the on-site supervising engineer, the geotextile membrane shall be laid.
2.7 The geotextile on the geotextile membrane is laid after the geotextile membrane is approved by Party A and the supervisor.
2.8 The geotextiles for each layer are numbered TN and BN.
2.9 The upper and lower layers of geotextile on the membrane should be buried together with the geotextile in the anchoring groove at the location where there is an anchoring groove.

 

3. Basic requirements for laying geotextiles:
3.1. The joint must intersect with the slope line; The distance between the horizontal joint and the slope foot that is balanced or may have stress must be greater than 1.5m.
3.2. On the slope, anchor one end of the geotextile, and then lower the roll material on the slope to ensure that the geotextile remains in a tight state.
3.3. All geotextiles must be pressed with sandbags, which will be used during the laying period and retained until the top layer of material is laid.

 

4. Geotextile laying process flow (see geotextile laying process flow chart on the next page)

                                                                                       Process flow diagram of geotextile laying

 

5. Technical requirements for laying geotextiles
5.1 Grassroots inspection: Check whether the grassroots is flat and solid. If there are foreign objects, they should be handled properly.
5.2 Trial laying: Based on the on-site situation, determine the size of the geotextile and cut it before trial laying. The cutting size should be accurate.
5.3 Check if the width of the salad is appropriate, the overlap should be flat, and the elasticity should be moderate.
5.4 Positioning: Use a hot air gun to bond the overlapping parts of two geotextiles, and the spacing between the bonding points should be appropriate.
When suturing overlapping areas, the suture line should be straight and the stitches should be even.
5.6 After stitching, check whether the geotextile is laid flat and whether there are any defects.
5.7 If there are any unsatisfactory phenomena, they should be repaired in a timely manner.

 

6. Self inspection and repair
a. All geotextile sheets and seams must be inspected. Defective geotextile pieces and seams must be clearly marked on the geotextile and repaired.
b. Worn geotextiles must be repaired by laying and hot connecting small pieces of geotextile, which should be at least 200mm longer than the edge of the defect in all directions. The hot connection must be strictly controlled to ensure that the geotextile patch and geotextile are tightly bonded and do not cause damage to the geotextile.
c. Before the end of each day's laying, visually inspect the surface of all geotextiles laid that day to ensure that all damaged areas have been marked and repaired immediately. Ensure that there are no foreign substances that may cause damage to the laying surface, such as fine needles, small nails, etc.
d. When repairing damaged geotextiles, the following technical requirements should be met:
e. The patch material used to fill holes or cracks should be consistent with geotextile.
f. The patch should extend at least 30 centimeters beyond the damaged geotextile range.
g. At the bottom of the landfill, if the crack of the geotextile exceeds 10% of the width of the roll, the damaged part must be cut off, and then the two geotextiles should be connected; If the crack on the slope exceeds 10% of the width of the roll, the roll of geotextile must be removed and replaced with a new roll.
h. The work shoes worn by construction personnel and the construction equipment used should not damage the geotextile. Construction personnel are not allowed to do anything that may harm the geotextile on the already laid geotextile, such as smoking or using sharp tools to poke the geotextile.
i. For the safety of geotextile materials, the packaging film should be opened before laying the geotextile, that is, one roll should be laid and one roll should be opened. And inspect the appearance quality.
j. Special suggestion: Geotextiles should be inspected and certified in a timely manner upon arrival at the site.
Strictly implement our company's "Construction and Acceptance Regulations for Geotextiles"

 

7. Precautions for installation and construction of geotextiles
7.1 Geotextiles can only be cut with a geotextile knife (hook knife). If cutting within the site, special protective measures must be taken for other materials to prevent unnecessary damage caused by cutting geotextiles;
During the laying of geotextiles, all necessary measures must be taken to prevent damage to the underlying layer of material;
7.3 When laying geotextiles, attention must be paid not to let materials such as stones, large amounts of dust or moisture that may damage the geotextile, block drainage channels or filter screens, or cause difficulties in subsequent connections enter the geotextile or underneath the geotextile;
7.4 After installation, visually inspect all geotextile surfaces to identify all damaged landlords, mark and repair them, and ensure that the laying surface is free of foreign substances that can cause damage, such as broken needles and other foreign objects;
The connection of 7.5 geotextiles must comply with the following regulations: under normal circumstances, there should be no horizontal connection on the slope surface (the connection must not intersect with the contour of the slope surface), except for the repaired area.
7.6 If stitching is used, the stitching thread must be made of materials that are the same or more than the geotextile material, and the stitching thread must be made of material that is resistant to chemical ultraviolet rays. There should be a noticeable color difference between the suture line and the geotextile for easy inspection.
During installation, special attention should be paid to stitching to ensure that no soil or gravel from the gravel cover layer enters the middle of the geotextile.

8. Damage and repair of geotextiles
8.1 At the suture junction, it is necessary to re suture and repair, and ensure that the end of the skipped needle has been re stitched
8.2 In all areas, except for rock slope sections, gaps or torn parts must be repaired and sutured with geotextile patches of the same material
8.3 At the bottom of the landfill, if the length of the crack exceeds 10% of the width of the roll, the damaged part must be cut off and the two parts of the geotextile should be connected.