With the development of urban construction, the improvement of people's living standards, the environmental function of water has been paid more and more attention by people. Artificial lakes have appeared in public playgrounds, residential areas, and various courtyards. In schools and other places, geomembrane is an artificial lake anti-seepage material, which has the advantages of light weight, large elongation, good anti-seepage performance, adaptability to deformation, simple construction and low cost.
One, the choice of anti-seepage materials.
The anti-seepage geomembrane is an important material for artificial lake anti-seepage. Therefore, it is necessary to select a suitable high-quality geomembrane first. At the same time, it is necessary to consider the construction convenience. When selecting the geomembrane, pay attention to the following points: .
1) When the thickness of the film is less than 0.35 mm, the welding process is difficult to hold when welding with a hot-melt welder in the field, and it is easy to cause leakage of the geomembrane due to the quality of the welding. .
2) During the lamination process, welds, especially cross-welds, should be minimized to reduce leakage hazards.
3) In addition, the water depth of the general artificial lake is about 3m and the depth is up to 5m. Therefore, it is necessary to ensure that the strength of the geomembrane is sufficient, and the foundation of the artificial lake is crucial, once the foundation appears large The degree of deformation, the geomembrane will withstand various loads.
Second, construction procedures.
1, excavate the shape of the lake according to the drawings, including the depth of the lake and the surrounding slope.
2, level the bottom of the lake and compact the base soil to repair the shape of the lake.
3, the outer facade is made of 180 or 240mm thick soil exterior wall, and the impermeable membrane is laid on the wall.
4, do hydrophobic blind ditch and collecting wells, overflow wells.
5, the bottom of the floor is paved with 150-200 thick gravel layer. The function of the gravel layer is to divert the groundwater to prevent the groundwater from jacking up the anti-seepage layer when the lake is drained.
6, the stone layer on the gravel layer or the 80mm thick leveling surface of the medium coarse sand layer.
7, 100 g of non-woven fabric layer is used as the isolation layer.
8, laying a 1mm LLDPE impermeable membrane.
9, laying 100 grams of non-woven fabric as a barrier.
10, laying cement stone powder mixed layer 100mm thick, and then batching 30mm thick mortar leveling layer, screeding layer 3*3m dividing seam (also can be used to lay 60 thick red brick on 60 thick stone powder layer) Layer, then batch 25 thick mortar leveling).
11, the surrounding facade is made of 180mm thick brick inner wall, which is the protective wall of the facade anti-seepage film.
Three, the main construction methods and technical measures
(1) Welding and paving of anti-seepage film:
1, according to the shape of the lake, slope, feed arrangement, etc., determine the site construction sequence, and the grass cloth manufacturers will then lay and weld.
2. Irregular parts shall be cut into different shapes of blocks according to the site conditions, and then the cut pieces of the anti-seepage film shall be welded by a special electric welder.
3, the welding part must be firm and dense, and the anti-seepage film is in the welding line. The upper and lower impermeable membranes must be melted to make them melt together, and the welding line should be smooth and color. Consistent, can not have spots, pockmarks, welding mouth application can not tear, welding machine temperature, walking speed should be strictly controlled according to the regulations to prevent welding is not strong or burn the waterproof membrane.
4, it is not possible to use a special welding torch for the construction of the corners of the welder.
(2) Construction of joints such as nozzles, column edges, and wall edges:
1, the pipe mouth part, you can first measure the pipe diameter, use the circle on the impermeable membrane to plan the circle smaller than the pipe diameter by 1-2mm, and then carefully cut and dig with the cutter, then put The anti-seepage film is inserted into the tube, and the tight fit is carried out. The base surface of the tube root portion should be firm and flat, and the sleeve is stabilized and then a welded tube-shaped waterproof membrane is added.
2, if the end of the pipe is too large or the column can not be inserted into the waterproof membrane, then the rubber sheet is wrapped tightly in the body part, and then the impermeable membrane is made into a sleeve-like shape. On the pipe, the steel pipe is tightened according to the pipe diameter. It is divided into two or more geotechnical film manufacturers, and then coated with waterproof glue. At the upper end of the interface, sealant is sealed.
3, some interfaces are on the underground concrete wall, then trim and flatten at the interface part, paste 5mm thick, 30-50mm wide rubber tape along the interface line to make the gasket, and then put the waterproof membrane on the top. Add a rubber mat belt, press a 1-2mm thick stainless steel pressure plate on the surface, and use the blasting rose to tighten the steel plate so that the interface can be tightly sealed, and a waterproof sealant is added to the seam along the trailing edge.
(3) Construction of the protective layer:
1, after repeated inspections, it is confirmed that the waterproofing membranes of the various waterproofing membranes are well welded, and when the large surface is not damaged, the protective insulating cloth can be laid, and the spreading should be carried out in sequence, with the shop. Stone powder or sand pressed.
2, the stone powder (sand) layer is placed on the protective cloth layer. The truck carrying the material cannot walk directly on the surface of the waterproof membrane. A layer of stone powder (sand) of 10 cm thick or more must be laid. , then pad 2 cm thick wooden board, in order to walk the hopper.
3, to transport large stones and materials to the lake, be careful to gently smear, do not throw directly on the waterproof layer, strictly prevent stones, bricks smash the waterproof membrane.
4, after the waterproof film is covered, the surrounding part is left overlapping, and the sharp object cannot be placed. Temporary protection measures should be taken, such as covering the anti-seepage film manufacturer with cloth, and then using it on the cloth. The wooden board and the bricks are pressed, and a layer of 100-150 thick stone powder can also be added.
5, if the soil is to be backfilled on the waterproof layer of the lake to make small islands or pile up boulder, the concrete layer of a certain thickness should be poured on the protective layer on the waterproof layer, and then The concrete layer is constructed for other constructions.
1. The heat coil, grinder and welder tow the power cord during use, must be away from its working part to avoid damage to the brain wires.
2. Except for hot air welding, the mouth of the heat gun should not be in contact with the HDPE film under any circumstances, and as far as possible away from the film surface, human body, machinery and other objects.
3. When not in use, the welder should not be placed directly on the HDPE film surface and should be placed on the bracket or sandbag belt.
4. After using the cutter, the blade should be retracted into the knife box immediately.
5. All kinds of temporary small tools used in the field should be put into the toolbox in time.
6. It is strictly forbidden to directly discard the solder from the nozzle of the extrusion welding machine on the geomembrane surface.
7. HDPE geomembrane construction site is prohibited from smoking. Do not wear shoes with nails or high-heeled hard-soled shoes to walk on the membrane surface. It is not allowed to engage in all activities that may damage the finished geomembrane.