Construction scheme of HDPE film impermeability in landfill
Number of hits：882019-12-10 00:00:00
新闻摘要:2. The foundation surface quality should meet the design requirements: the foundation pit bottom surface, the slope surface and slope ratio, the Anchorage groove on the slope, the slope surface and the junction of the right surface should be treated, and
Chapter 1 Basic Requirements
1. Before laying the HDPE geotechnical film, it shall conduct a comprehensive inspection of the laying substrate in conjunction with the civil construction, supervision, design, and owner, meet the design requirements, meet the construction conditions, and make a handover inspection record after Fangkeshigong.
2. The foundation surface quality should meet the design requirements: the foundation pit bottom surface, the slope surface and slope ratio, the Anchorage groove on the slope, the slope surface and the junction of the right surface should be treated, and the base surface of the warehouse wall concrete structure should strictly meet the design requirements.
3. The base surface should be dry, compacted, flat, no cracks, no obvious sharp process, no mud, no depression, and the vertical depth of 25mm should have roots, rubble, stones, steel muscles, and glass chips. The smoothness should be changed gently within the allowed range, the slope is uniform and the slope is the same.
4. The angle of the yin and Yang on the base surface has a smooth transition, and the root of the column should be made into a circular arc.
5. The surface of the basement is dry and the moisture content should be less than 15 %.
6. The base should be compact and uniform, and the dry density of the soil base should not be less than 1.4 T / M2.
7. After the civil construction, supervision, design unit, owner, and general contractor accept and sign the approval, the construction of the earth paving film can be carried out.
Chapter II. Climate Requirements for Construction
1. The temperature should generally be above 5 degrees Celsius, the geotechnical film should be tight at low temperatures, and the geotechnical film should be relaxed at high temperatures.
2. The wind is below level 4.
3. When the temperature is too low, wind and snow weather above level 4 should not be constructed.
4. In the wind weather, wind power affects the geotechnical membrane construction, the HDPE geotechnical membrane to be welded should be pressed with sand bags.
Chapter III. Layout of HDPE Shop
1. Before laying the HDPE geotechnical film, the corresponding qualified acceptance certificate of the civil engineering shall be provided.
2. Before HDPE film cutting, it should be accurately measured and then cut according to the actual size. Generally, it is not appropriate to cut according to the icon size. It should be numbered by piece and recorded in detail on a special form.
3. When laying HDPE geotechnical film should strive to weld the least, under the premise of ensuring quality, as much as possible to save raw materials. It is also easy to ensure quality.
4. The joint width between the membrane and the membrane is generally not less than 10cm, and the weld alignment direction is usually parallel to the maximum slope, that is, arranged along the slope direction.
5. Usually in corners and deformed areas, the length of seams should be reduced as much as possible. Except for special requirements, as far as possible, no weld is provided on slopes with a slope greater than 1:6 within 1.5 meters of the top slope or stress concentration area.
6. In the laying of HDPE geotechnical film, artificial folds should be avoided. When the temperature is low, it should be tightened and paved as much as possible.
7. After the HDPE geotechnical membrane is laid, it should be minimized to walk on the membrane surface, move tools, etc.. Anything that can cause harm to the HDPE membrane should not be placed on the membrane or carried on the membrane to avoid accidental damage to the membrane..
Chapter IV. Welding of Geotechnical Membrane
1. The welding process of the hot welding machine is divided into: adjusting the pressure setting temperature, setting the speed weld joint, checking the loading film into the machine to start the motor pressurized welding.
2. There must be no oil pollution or dust at the seams. The joint surface of the HDPE geotechnical membrane should not contain silt and other debris. When there is debris, it must be cleaned before welding.
3. At the beginning of each day's welding, a sample of 0.9 mm x 0.3 mm shall be first tested on the site, the bonding width shall not be less than 10 cm, and the stripping and shear tests shall be carried out on the site of the drawing machine. After the specimen has passed, It can be welded with the speed, pressure, and temperature that were adjusted at the time. Date, time and ambient temperature shall be indicated on the specimen. During the welding process, the hot welding machine should pay attention to the operation of the welding machine at any time, and the speed and temperature should be fine-tuned according to the actual situation on the scene.
4. Weld requirements are neat, beautiful, no sliding welding, jumping phenomenon.
5. When the length of the geotechnical film is not enough, long splicing is required. The horizontal weld should be welded first, and then the longitudinal seam should be welded. The horizontal weld distance greater than 50cm should be T shaped and must not cross.
6. The adjacent geotechnical film welds should be spliced as much as possible, and the nodes formed between the film blocks should be T-shaped, minimizing the cross type, and the vertical mold should be strengthened at the intersection of the welds.
7. When welding the film, it is not allowed to press out dead folds. When laying the HDPE geotechnical film, according to the local temperature change and the performance requirements of the HDPE geotechnical film, the amount of retractable deformation caused by temperature change is reserved.
8. When the temperature of the welding machine indicated by the temperature control of the portable welding machine is less than 200 °C, it is necessary to use clean cloth or cotton yarn to brush off and weld again. If necessary, it should be re-polished. Do not use your hands to try.
9. When the joint has the influence of dew, humidity, sediment, etc., the welding is performed after treatment.
10. Welding can not be performed during rain or when there is moisture, dew, or large sand at seams, except for protective measures.
11. When the temperature is below 5 °C, construction should not be carried out according to the specifications. If construction is necessary, the welding machine should be preheated before welding.
12. In the welding process, the extruded welding machine should often check the slider of the gun head. When the wear is serious, the slider should be replaced in time to avoid damage to the film surface.
13. The geotechnical film should be powered by a generator with good voltage stabilization performance when welding. When using local electricity in special cases, a voltage regulator must be used.
Chapter 5. Anchoring of HDPE Membrane
1. There are three methods of anchoring: groove Anchorage, bolt Anchorage and expansion bolt Anchorage; In general, groove Anchorage is used.
2. When using groove Anchorage, depending on the conditions of use and force of the HDPE geotechnical membrane, the Anchorage groove width is generally not less than 0.5 M-1 .0 M, and its depth is not less than 0.5 M-1 .0 M.
3. When using nail Anchorage, the width of the pressure strip shall not be less than 2cm, the thickness shall not be less than 2mm, the pitch of the nail shall not be greater than 400mm, and the embalming measures shall be taken at the exposed place of the pressure strip.
4. When using expansion bolt anchoring, the diameter of the bolt is not less than 4mm, and the spacing is not more than 0.5 mm. When construction is carried out, the film in the position is temporarily fixed with a ready sandbag to prevent the wind from blowing the HDPE film and then the expansion bolt Anchorage.
Chapter 6. Notes for Construction of Geomembrane1. Electrical equipment and power supply lines shall conform to relevant professional standards.
2. The power cord of the hot air gun, sand turbine and welding machine towing belt must be kept away from its work location to the maximum extent possible during use, so as not to damage the brain wire to leak electricity.
3. With the exception of hot air welding, the mouth of the hot air gun must not come into contact with the HDPE membrane under any circumstances and be as far away from the membrane surface, human body, machinery and other objects as possible.
4. When the welder is not in use, it must not be placed directly on the HDPE film surface. It should be placed on the bracket or sandbag belt.
5. After the cutting knife is used, the blade shall be immediately recovered from the knife box.
6. All temporary small tools used in the field, after use, should be placed in the toolbox in a timely manner.
7. It is forbidden to discard solder material taken from the head of the extruded welding machine directly on the surface of the geotechnical film.
8. Seat belts and safety helmets must be worn when operating in dangerous places such as steep slopes.
9. Smoking is prohibited at the HDPE geotechnical film construction site. Fire facilities should also be provided. Shoes with iron nails or high heels and hard shoes should not be worn on the membrane surface. All activities that may damage the finished geotechnical film products are not allowed.
Chapter VII Inspection and Repair of Geotechnical Membrane Products
1. The welder operator shall indicate the welder's name and name and the time of welding at the welding sample and the weld seam of the construction.
2. The construction log shall be made by the project manager or construction captain during the construction process.
3. The test is carried out in three steps, namely visual, inflatable and destructive tests.
4. Visual inspection is mainly to lay the appearance of geotechnical film, weld quality, T-type welding, substrate debris, etc. to carry out careful inspection, all construction personnel should be carried out in the entire construction process.
5. In addition to inspection, vacuum inspection should also be used for all weld strictness, and self-inspection should be strengthened for those parts that can not be tested in vacuum.
6. The inflatable strength of the filled pressure test is 0.25 Mpa, 5 minutes without leakage, and the pressure is allowed to drop by 20 % considering that the coil is relatively soft and easily deformed.
7. When the strain test is conducted on the sample block taken on the two-track weld, the standard is that when the weld is not torn and the mother is torn, the weld is damaged. At this time, the welding is qualified. If the specimen is not qualified, The second piece should be taken from the original weld. If the three pieces are not qualified, the entire weld should be reworked.
8. The sample blocks that have passed the test are sent to the owners, general contractors and related units for archiving.
9. For the defects found in the visual inspection, inflatable inspection, and damage test, they should be repaired in time. If they can not be repaired immediately, they must be marked to prevent them from being missed during repair.
10. Appearance inspection, found that the film surface has holes and other defects in the welding process, and in the case of leakage welding, virtual welding, damage, etc., should be promptly repaired with fresh master material, repair each side of the damage site 10-20cm. And keep a record.
11. For repaired welds, detailed visual inspection is generally performed to confirm that the repair is reliable before release.