Construction method of waterproof blanket

The construction procedure of waterproof blanket seepage control project is: construction preparation → foundation surface treatment → plain soil compaction → waterproof blanket laying → waterproof blanket anchoring → sandy loam backfill. ?

1, grassroots processing?

(1) The surface shall be basically dry, free from obvious water stains and potholes, and free from stones and clods protruding more than 2cm. Remove foreign objects that may damage the waterproof blanket, such as tree roots, gravel, construction waste, garbage, etc. ?

(2) Before laying the bentonite waterproof blanket, the bottom must be leveled and compacted, and the degree of compaction should be above 0.93. There should be no rutting, footprints and other irregular marks on the waterproof blanket laying site. ?

(3) According to the procedure, before laying the waterproof blanket, it should be reported to the supervision engineer to verify whether the foundation conditions meet the requirements, and the waterproof blanket can be laid only after it is accepted. ?

(4) φ50mm arc or 50×50mm obtuse angle cement mortar shall be used for the contact part between the foundation and the straight wall revetment.

2. Bentonite waterproof blanket laying?

(1) Preparation before laying: Make blanking analysis and draw the laying sequence and cutting diagram of bentonite waterproof blanket.

(2) Check the appearance quality of bentonite waterproof blanket, and record the defects such as damage, trauma and holes that have been found, so as to repair them when laying. ?

(3) The construction of waterproof blanket should be carried out in rainy days. In case of rain during construction, it should be covered with plastic film to prevent hydration of bentonite waterproof blanket.

(4) After the foundation meets the requirements, the waterproof blanket should be laid in the direction of water flow, with geotextile (black surface) facing downwards and non-woven fabric (white surface) facing upwards, with the bank slope (bank protection) first and then the bottom layer, that is, the bentonite waterproof blanket in the upstream is stacked on the bentonite waterproof blanket in the downstream. ?

3. Anchorage of waterproof blanket?

(1) The slope of the main channel whose river slope ratio is not steeper than 1:3 shall be anchored by anchor channel method, and the anchor channel (30cm×30cm) shall be backfilled and anchored, without sharp corners. ?

(2) The waterproof blanket should be fixed at the top, and its end should be placed in the anchorage ditch at the top of the slope, and the anchorage ditch should exceed the top of the slope 1m or more. ?

(3) Bury the waterproof blanket into the ditch. The waterproof blanket must continue to the bottom of the ditch, and then cover the soil for backfilling, with the compactness reaching above 0.9.

4, waterproof blanket lap

(1) Ground overlap: the ground should be laid in parallel, and the waterproof blanket in the upstream of the water flow should be pressed against the waterproof blanket in the downstream, and the cloth surface should not be stretched or wrinkled. ?

(2) Oblique lap: The laying and lapping of waterproof blanket are parallel to the inclined direction of the slope, and the waterproof blanket on the bank slope can only be lapped vertically, but not horizontally.

(3) Lapping refers to the overlapping of the edges of two waterproof blankets, the overlapping length is more than or equal to ≥30cm, and 0.4 kg-0.6 kg/m bentonite powder is evenly spread at the overlapping place. After laying the lap joint, uncover the lap joint, and then spread it evenly in the belt area 15cm wide at the end of the waterproof blanket, so as to ensure the dosage of waterproof powder, and spread it evenly without damage.

5. Construction of protective layer? The construction of protective layer is the key link to ensure the waterproof effect of waterproof blanket, and the following requirements must be met: (1) After the waterproof blanket is laid, the construction of protective layer must be completed on the same day (to ensure that it is not wet by water). (2) In the process of protective layer, be careful not to damage the waterproof blanket. If it is damaged, it should be repaired in time. ?

6. Covering soil and backfilling?

After laying waterproof blanket, backfill construction must be completed on the same day. It is best to use screened soil for all backfill soil, the particle size is less than 5mm, and there are no sharp stones and sundries. The soil shall not contain stones and other sundries above10 mm. The thickness of backfill soil is 30cm, and its compactness is not less than 0.9. During tamping and compaction, care should be taken not to damage parts. If it is damaged, it should be repaired as required.