Preventive measures for common quality problems in resettlement community projects?
A, the foundation pit edge backfill soil subsidence
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2. Cause analysis:
1) Backfill before foundation pit water and silt are removed; Or backfill with loose soil, not layered compaction; Or the loose soil flow at the edge of the groove, such as foundation pit, is not treated seriously before tamping, and the backfill soil is soaked in water to produce subsidence.
2) The narrow foundation trench is filled by manual tamping, which can not meet the required compactness.
3) Dry clods in the backfill soil are submerged by water, or cohesive soil, muddy soil and broken turf with high water content are used as soil materials, so the backfill quality is not ideal.
3. Preventive measures
1) Before the foundation pit (ditch) is backfilled, the water in the ditch should be drained, and the silt, scarification and sundries should be cleaned. If there is groundwater or accumulated water, drainage measures should be taken.
2) Backfill soil shall be strictly backfilled and compacted by layers. The thickness of each layer of virtual paving soil shall not be greater than 30cm. Soil material and water content should comply with the regulations, and the compactness of backfill soil should be sampled and checked according to the regulations and meet the requirements.
3) Backfill soil shall not contain clods with a diameter greater than 50 cm, and shall not have dry clods. When the next procedure needs to be carried out on backfill soil urgently, lime soil backfill should be adopted.
4) During construction, it is forbidden to backfill earthwork by water sinking method. In order to prevent sudden precipitation during backfilling, covering and drainage measures must be taken. When necessary, dig out the permanently submerged earthwork and backfill it with good soil.
5) During earthwork backfilling, in case of rainy season, the construction measures of earthwork backfilling in rainy season should be taken.
Second, the phenomenon of water seepage and leakage.
(a) Measures to prevent water seepage from external walls
1. Cause analysis: Incorrect caulking material and operation technology of external wall curtain wall will cause water seepage at the window.
2. Precautions: Sealing materials shall be tightly blocked with closed-cell materials. When sealing, sealing should be symmetrical inside and outside, and sealing should be done twice. After the first joint filling, the second joint filling can only be done once a night. The joint surface should be compacted and flattened, about 2mm concave than the outside of the block. After joint filling is completed, sealant should be applied around.
(2) Measures to prevent water leakage in the pool body
1. Cause analysis: The waterproof layer material of the tank body is not up to standard, the construction joints are not handled well, and the waterproof layer coated with film is uneven, which leads to frequent water leakage and water leakage.
2. Precautionary measures: The concrete of the pool body shall be poured in strict accordance with the construction plan, and the lien and treatment of construction joints and concrete pouring shall be strictly monitored to prevent concrete defects caused by improper operation. Waterproof coatings with long service life and good quality should be used. Basic treatment in place, smooth surface, uniform coating thickness, meet the design requirements.
(3) Measures to prevent water leakage from reserved holes of downspouts and risers
1. Cause analysis: When repairing the reserved holes in downspouts and riser, water leakage occurred in many places due to reasons such as incomplete cleaning of garbage powder, insufficient wetting, and dense pouring of fine stone concrete powder.
2. Precautions: The water outlet should be 10 ~ 15mm lower than the waterproof layer of the floor and roof, and be made into a basin-shaped water outlet. Repair method of reserved hole: chisel away the loose parts on the four walls of reserved hole, remove clean garbage, fully wet the hole wall and pipeline surface with water, and brush the construction cement mortar on the joint surface once. First pour 10 ~ 2 omm thick l:2 cement mortar, then pour C20 fine stone alkali with slump of 6 ~ 8 cm, tamp it with iron bars, level the surface, and make it about 3mm concave. The next day, at the joints of fine stone concrete around the pipes and downspouts, l:2 cement mortar with a thickness of 1.5 ~ 2mm was embedded, about 10mm. Floor and roof, after the riser is completed, use 1:2 cement mortar to make waterproof "small steamed buns", and the reserved holes should be repaired by special personnel. The repaired reserved holes should be clearly listed, and the riser is not allowed to shake within 24 hours.
(4) Measures to prevent water leakage of pipes and sanitary wares
1. Cause analysis: Because the pipe joint is not tightly sealed, water leakage often occurs in pipes and sanitary ware.
2. Precautionary measures: Before pipeline installation, sewage and wastewater pipelines should be inspected by specialized personnel through flushing. Tap the pipe with a small hammer to listen to the sound and check for cracks. If sand skin or cracks are found, they should be removed before use. When installing pipelines, waste water and sewage pipelines should be temporarily fixed firmly after the positions of each pipeline section are correct, and embedded firmly with the original cement joints, which should be clearly listed and must not shake within 24 hours. Where individual pipes shake, the asbestos cement at the joint must be chiseled off and re-embedded: for the water joint, it is advisable to use water paint hemp pad and tighten the coil; When installing the toilet, use the "cross" level to control its levelness, and ensure that the sewage pipe joint has enough length and is tightly embedded; Both ends of the copper pipe of the toilet tank should also be wrapped tightly with white lacquer hemp, and the copper nut should be tightened to ensure that the copper pipe has enough length.
Third, measures to prevent pipeline blockage
1. Cause analysis: During the installation process, cement mortar, concrete blocks, clods and other sundries fell into the pipeline, causing blockage and seriously affecting the use.
2. Precautions: For the upper opening and downspout of sewage and wastewater riser, a 3mm thick steel plate "cover" and a cork can be used for temporary sealing respectively. Lift the height of the riser at any time, move the cover upward continuously, and temporarily seal the upper water nozzle with a "hard head".
Fourth, flood control measures.
1. Cause analysis: the slope direction of water flow is incorrect and the elevation control is not good.
2. Precautions: During the ground construction of toilets and rooms with floor drains, according to the requirements of ground flooding and the 5cm horizontal chalk line on the four walls, make a flat cake on the base of the building with a level, then screed, spread fine stone concrete and scrape it flat. For the roof, according to the requirements of flooding, measure and control with a level, do a good job of cake collapse of subbase, then use fine stone concrete to find slope and scrape arc, smooth it with 1:2 cement mortar powder, and polish the surface with a wooden wedge.
Five, coating quality common fault and prevention
Common faults of 1, 0,0: brush leakage, uneven yin and yang angles, unclear edges and corners, sagging, wrinkles, metal pollution, flashing, roughness and so on.
2, prevention and control:
1) The moisture content of the base course should not be greater than 10%, and the surface should be smooth, clean and free of dirt.
2) Batch of putty shall be configured as required, and shall have a certain strength after drying, and shall not be pulverized, peeled or cracked.
3) The pulp skin is cracked. At last, the base is not cleaned, and the last batch of putty is dry, which is prone to surface cracking.
4) Peeling: Peeling occurs when the slurry is too thick or latex paint is prepared according to the proportion specified in the standard. Therefore, the paint should be prepared in strict accordance with the regulations.
5) alkali returning and color biting; The main reason is that the wall is too wet, or the wall is not dry and wet. The solution is to dry the wall and wait until the wall is dry before construction. In addition, the brushing times should not be too tight, and the second construction should be carried out after the first drying.
6) Sagging: The viscosity of the coating is too high, which is easy to cause sagging, so it is necessary to master the preparation ratio of the coating.
Six, brick quality common fault and prevention
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2, the surface is not clean: after the completion of the ground pavement, the finished product protection is not enough, paint barrels are placed on the ground, cement is mixed on the floor tiles, and mortar is not covered, which will cause surface pollution.
3. Uneven paving: the opposite brick is not selected in advance, the height difference is caused by inconsistent brick thickness, or the paving is not strictly controlled according to the horizontal line.
Seven, installation engineering quality common fault prevention and control methods
(1) Prevention and treatment of common quality defects in pipeline specialty
1. Pipe supports shall be cut mechanically, and gas cutting is strictly prohibited. After cutting, it should be polished with a grinder. Rows of stents should be made evenly, and the stents should be installed firmly and reliably without shaking. Before the bracket is painted, it should be derusted and qualified, and then painted with antirust paint and topcoat.
2. Derusting work should be done well before pipeline painting, and there should be no brush leakage or flowing phenomenon in painting engineering. Welded joints shall be carried out after the pipeline pressure test is completed.
3, pipe installation should be horizontal and vertical, levelness and verticality should comply with the specification requirements, pipe bracket spacing should comply with the specification requirements.
4, threaded pipe installation should pay attention to do not produce broken wires, wild species, silk mouth should be exposed 2 ~ 3 buttons, silk mouth galvanized layer damage should be treated with antirust paint, timely clean up the exposed hemp or raw material belt.
5. The welding quality of welded steel pipes should be well controlled, and the welding procedure qualification should be done well before welding, and there should be no common quality defects such as slag inclusion, honeycomb, penetration and flowing. After welding, the flash should be removed in time.
6, flange bolts should be consistent in specifications, uniform in length, and exposed for 2 ~ 3 buttons.
(B) electrical professional quality common fault prevention and control
1. During the embedding stage, attention should be paid to prevent the embedded pipeline and box from shifting or dislocation.
2, the pipe hate bending to control the size, shall not produce cracking and wrinkling phenomenon.
3, pipeline paint comes into play to prevent flowing, rust, brush leakage and other problems.
4, pipe bracket spacing should comply with the regulations, shall not be gas cutting.
5, the diameter of the jumper round steel to meet the requirements, the welding length shall not be less than 6 times the diameter. Electrical equipment, trunking, bridge, pipeline, cabinet and foundation channel steel must be reliably bridged and grounded. The practice of each grounding terminal should meet the requirements of the specification.
6. The installation elevation of lamps, switches and sockets shall be constructed in strict accordance with the design requirements, and the height difference of switches and sockets in the unified place shall not exceed 5 mm ..
7, sanitary ware and pipe fittings installation height, location to comply with the design and specification requirements, after the installation, installation requirements to do a good job of water storage test.
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