● Foundation excavation ● Make a mortar protective layer (H20-30mm) at the bottom of the lake.
● Slope cutting, compaction and leveling ● Composite geomembrane is bonded to the vertical water retaining wall.
● Leveling, cleaning and process handover of foundation surface ● Sealing of underwater water pipe mouth to stop water.
● Laying and welding of composite geomembrane ● Process handover
● Acceptance of welding and repair quality ● Completion acceptance
Second, the project overview
1. Maximum design water level: about 0.6m
2. The total waterproof building area is about 800㎡.
3, ceramsite brick masonry water retaining wall.
There is a sinkhole under the water.
Third, the main waterproof materials
1, composite geomembrane coil, specification: 50 * 4m150g/㎡/0.5mm/150g/㎡.
2. GB rubber water stop.
Fourth, the basic conditions
1. After the foundation is formed and excavated, the slope shall be cut, leveled, rolled or compacted. The replacement of disturbed soil shall be watered, rolled or compacted by layers, and the thickness of each layer shall be ≯ 400 mm ..
2. Remove the substances exposed on the foundation surface that may puncture, such as bricks, stones and tiles; Glass and metal fragments; Branches, roots, etc.
Clean up the obstacles in the field and provide necessary laying construction conditions.
3. Before the construction of composite geomembrane, the installation and reservation of surrounding water retaining wall, pump pit, bridge foundation and underwater nozzle must be completed.
Five, welding and laying technology
1, welding technology
① Weld lap width: 80 ~100 mm; The natural folds in plane and vertical plane are: 5% ~ 8% respectively; Reserved expansion: 3% ~ 5%; Remaining: 2%~5%.
(2) The working temperature of hot melt welding is 280 ~ 300℃; The traveling speed is 2 ~ 3m/min；; The welding form is double-pass welding.
③ Repair method of damaged parts: cutting materials with the same specifications, hot-melt bonding and sealing with polyethylene glue.
(4) There is no cloth connection at the weld bead, and mechanical sewing is adopted.
⑤ The underwater nozzle is sealed with national standard rubber waterstop, wrapped with metal and treated with anti-corrosion.
2. Laying technology
① The laying direction of composite geomembrane should be from E to W or from W to E, and the laying length of each piece, including the height of water retaining walls on both sides, should be completed at one time.
(2) Laying sequence, from the channel axis to the S and N sides.
(3) Construction technology: firstly, make a mortar protective layer (20-30mm) of composite geomembrane at the bottom of the lake, and then stick it with the vertical water retaining wall.
④ Bonding technology between composite geomembrane and water retaining wall. Apply adhesive to the bonding surface between the composite geomembrane and the retaining wall, dry it, let it stand for about 5 minutes, and then paste, squeeze and flatten it. The adhesive is a mixture of asphalt latex paint, cement and water. After pasting, anchor the nail above the water surface and do waterproof and anticorrosive treatment.
Six, quality acceptance
1. The materials and construction of composite geomembrane shall conform to the national standards for polyethylene geomembrane and composite geomembrane promulgated by the State Bureau of Quality and Technical Supervision.
2. Acceptance of construction quality includes self-inspection by the construction unit and sampling inspection by the contractor.
3. The welding quality inspection adopts "inflation and pressurization method" and the damage repair adopts "visual inspection method". The inflation pressure detection index is 0.06Mpa.
4, quality acceptance process, including process handover procedures, completion acceptance, etc.
5. Normal leakage of artificial lake: ≤ 15mm/24h (including seasonal evaporation loss).
Seven. construction progress
1, daily efficiency, one unit is calculated according to the construction area of 2000 ~ 2500m2 per day.
2. The planned construction period is 3 days.
Eight. suggestion
1, strengthen the protection and management of composite geomembrane products, improve the waterproof awareness of relevant construction personnel, ensure the engineering quality and put into normal operation on schedule. It means a lot.
2. It is suggested that the contractor notify and assign special personnel to supervise. If the construction personnel related to waterproof materials find that the composite geomembrane is damaged, they should promptly notify the waterproof construction personnel to repair it.
3. The composite geomembrane must prevent oil from sticking, otherwise it will reduce the bonding strength. For storage and protection, see the brief introduction of geomembrane construction method.
4. It is suggested to pay attention to the following links in this project:
(1) After the composite geomembrane is welded into a finished product, the lake bottom mortar protection layer must be made first.
(2) The bridge foundation is waterproof, adopting the method of welding steel bars through the membrane, and adopting the mortar protective layer to prevent the quality hidden trouble caused by electric welding.
(3) When the composite geomembrane is pasted on the wall, large-area hollowing must be prevented.