Precautions For Laying Composite Geomembrane

Composite geomembrane is suitable for water conservancy, chemical industry, construction, transportation, subway, tunnel, 

garbage disposal site and other projects, construction needs to be carried out in accordance with the standard construction methods:

1. Preparation for construction

(1) Composite geomembrane material quality detection: the composite geomembrane used is two cloth and one membrane composite geomembrane.

(2) Cleaning and leveling the site of the embankment slope, removing all sharp corner debris, underslope backfill compaction, rich slope cutting slope excavation after the 

supervision acceptance, providing a working surface for composite geomembrane laying.

(3) In-situ geomembrane splicing In order to facilitate construction and ensure splicing quality, the composite geomembrane should be as wide as possible to reduce the 

amount of splicing on site. Before construction, the composite geomembrane should be cut in the unit according to the width and length of the composite geomembrane, 

and spliced into a block of the required size, rolled on the steel pipe, and manually transported to the working surface for lay.

2, the laying of composite geomembrane

(1) Laying method:

composite geomembrane laying is divided into two parts: canal bottom laying and slope laying. Channel bottom laying: horizontal rolling along the 

axis of the channel. Slope laying: After acceptance of the slope, rolling from the direction of the slope axis, and the composite geomemofilm connected with the bottom of the 

canal adopts T-shaped connection.

(2) Laying technical requirements:

 Laying should be carried out in dry and warm weather, in order to facilitate splicing and prevent stress concentration, the composite

geomembrane is laid in a wavy relaxation mode, with a surplus of about 1.5%.  After spreading out, the composite geomembrane should be flattened and pulled apart in time,requiring that the composite geomembrane is consistent and smooth with the slope without protrusion and folds.  The construction personnel should wear flat cloth shoes or soft rubber shoes, and it is strictly prohibited to wear cleats to avoid trampling the geomembrane.  If the geomembrane is found damaged during construction, it should be repaired in time.

3. Splicing of composite geomembrane

(1) The splicing of composite geomembrane includes the joint of geotextile and the welding of geomembrane, and the welding is performed by hot fusion welding. In order 

to ensure the quality of welding, welding should be carried out in the factory as far as possible, but in order to facilitate construction, the width of the composite 

geomembrane should not be too wide, and it must be spliced at the construction site.

(2) The quality of composite geomembrane welding is the key to the success or failure of composite geomembrane impermeability, so it is necessary to do a good job of 

geomembrane welding to ensure the quality of welding, therefore, geomembrane welding should be sent by the manufacturer to the site operation, guidance, training, the use 

of geomembrane special welding equipment.

(3) Welding process: After the first piece of geomembrane is laid, the edge to be welded is folded (about 60cm wide), the second piece is spread on the first film in reverse, and 

the welding edge of the two films is adjusted to make it lap 10cm.

(4) Before welding, use a hairdryer to blow away the sand, soil and other dirt on the film surface to ensure that the film surface is clean, and put a long wood under the welding 

part, so that the welder can walk on the flat base surface to ensure the welding quality. Before formal welding, test welding is carried out according to the construction temperature to determine the walking speed and welding temperature, and generally master the walking speed of 1.5 ~ 2.5m/s. The welding temperature is 220 ~ 300 0C. Two splicing welds, each 10mm wide, with a 10mm cavity between the two welds, with this cavity to check the quality of the weld.

4. Anchorage of composite geomembrane

Composite geomembrane upper anchorage adopts composite geomembrane with sufficient length embedded at the top of the embankment.

5. Cushion layer and concrete guard

The composite geomembrane is evenly laid with 10cm sand cushion layer, and 10cm concrete is laid after leveling and patting. After the slope composite geomembrane is qualified, the cushion cover should be laid in time to prevent wind blowing and the composite geomembrane from being exposed to the sun and aging, and the concrete guard should be made to strengthen the protection of the composite geomembrane.

1. the use must be embedded: the coverage thickness should not be less than 30cm.

2. repair anti-seepage system should be: cushion layer, anti-seepage layer, transition layer, protective layer composition.

3. the soil should be solid, to avoid uneven subsidence, cracks, anti-seepage range of turf, roots to be removed. The contact surface with the geomembrane should be laid 

with sand or clay with small particle size as a protective layer.

4. when laying the geomembrane should not be pulled too tight, it is better to be corrugated at both ends, especially when anchoring with rigid materials, there should be a 

certain amount of expansion.

5. construction, should avoid stones, heavy objects directly on the geomembrane, it is best to side construction, side laying film, side covering protective layer.