The construction work belt and the access road are mechanically or manually, and the ditch, ridge and slope within the construction area are leveled, and the construction vehicle, the transportation vehicle and the construction machine can be flexibly operated, and the transportation pipe is convenient. Leveling quality supervision should be checked for approval. For the construction site far away from the road, it is necessary to construct the access road for the construction, so that the construction machinery can enter the site and transport the pipeline and construction materials. The equipment used is a bulldozer (D60 or D80) and a single bucket excavator.
The quality of excavation pipe trench trench excavation has a great impact on the buried depth quality of the pipeline, and the buried depth does not meet the design requirements, which will affect the future safe operation. Pipe trench excavation shall be carried out according to the drawings, and shall not be arbitrarily changed.
Pipe trench excavation should be reasonably arranged according to the construction progress. At the same time, it should be determined according to geological conditions and construction season. Some pipe trenches are dug after the pipeline is welded, and some pipe trenches are dug in advance. For the stone section, the trench must be dug in front of the pipeline, otherwise the blasting splash will damage the anticorrosive layer of the steel pipe. For pipeline construction in alpine regions in winter, the trenches should be excavated before freezing in winter. For the sandy land quality area, the water level is higher, the pipe ditch is excavated after the pipeline is welded, the flaw detection is qualified, and the filling is completed. After the pipe trench is dug, the pipeline immediately goes down the ditch to avoid landslide and ensure the quality of the buried depth of the pipeline.
In the past, who was responsible for the construction of the pipe section, who is responsible for anti-corrosion, so the three engineering companies of the Pipeline Bureau have their own anti-corrosion plants; most of the anti-corrosion materials use asphalt anti-corrosion, which will not reach the service life, and the pipeline maintenance cost is high after the production. Now the pipeline is anti-corrosion, the asphalt anti-corrosion is eliminated, and new anti-corrosion materials such as epoxy coal tar pitch, epoxy powder and polyethylene are adopted; at the same time, the anti-corrosion structure is also changed. For example, the Shaanxi-Beijing line adopts FBE three-layer structure for anticorrosion.
Elbows and elbows for pipe prefabricated pipelines need to be prefabricated in advance. In our early pipeline construction, the elbow used for the line was 2.5 times hot elbow, and the rest were elastically laid. In the place where the elbow is used, the fixed pier should be added, the quality of the anti-corrosion can not be guaranteed, and the quality of the fixed pier is not guaranteed. Now the pipeline adopts the cold-bent elbow to solve the above contradiction. The radius of the hot elbow is also increased to five times the diameter of the pipe. Moreover, elbows and elbows are not allowed to be cut. Need to use a large angle of elbows or bends, then pre-made how big, check the seat.
For the transportation of anti-corrosion pipe, the transportation of anti-corrosion pipe should have a special pipe trailer. In order to protect the nozzle and the corrosion layer, a special spreader should be used for lifting. Each layer and each pipe should be separated by a cushion layer. Special rigging, that is, high-strength nylon soft belt. Pipes transported to the construction site shall be dumped and unloaded according to the requirements of the construction unit. The unloading pipe shall also be equipped with a special spreader. The unloaded pipe shall not be placed directly in the ground. It shall be padded off the ground with a cushion layer and a soft soil bag. Also be separated by a cushion. The pipes transported to the site shall be checked and accepted by the construction unit one by one, and the handover procedures shall be handled. If the anti-corrosion layer and the damaged pipe are damaged during transportation, the transportation unit shall be responsible. If the construction unit repairs, the transportation unit shall bear the expenses. Regardless of whether it is internal transportation or foreign transportation, it is necessary to distinguish between responsibility and economic interests, so as to increase responsibility and ensure the quality of the pipe.
On-site pipe laying is carried out by pipe hanger pipe, pipe is to be discharged (the pipe trench is not dug), the pipes are connected one by one, and the two pipes are staggered. Each pipe should be grounded with soft mounds or sandbags and cannot be placed directly on the ground. A special rigging is used for the pipe, and a thick rubber pad is applied to the pipe hanger at the pipe hanger. On-site piping should pay special attention to protect the anti-corrosion layer and nozzle of the pipe section. It is not allowed to be piped by rolling, rolling or smashing.
The technical documents are prepared to prepare the necessary documents for the construction of the organization, the quality manual, the quality control procedure documents, the construction organization management (personnel organization and various management systems), the process construction procedure documents, the welding procedure qualification and the welding procedure regulations. At the same time, it is necessary to prepare and report the road and railway crossing plan; the river crossing plan; the elbow and elbow production procedure documents; the pipe pass ball test plan.
The construction and technical workers must be trained and qualified to pass the training and certification. Management and construction of electric welder training and certification is a task with a large workload. The manpower, capital and materials invested are the most important, and must be carried out earnestly. A leadership team is set up to specialize in training. That is responsible for organizing nozzle processing, welding consumables procurement, welding machine and site preparation, welding training, arranging technical instructors and inspectors, and organizing certification. Grinding wheel, electric welding glass, disc wire brush, coarse sand for derusting and other construction consumables, safety and fireproof materials such as fire extinguishers, fire buckets, shovel, axe, labor protection clothing and supplies, etc., should be prepared adequately.
In the case of preparation work, the owner and the supervisor shall conduct inspections; the preparatory work is insufficient, the construction quality is not guaranteed, and the necessary preparatory work is not completed, and the owner and the supervisor are not allowed to start construction.
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