Pipe network construction in rainy season, precautions for backfilling and laying of carat pipes

Key points of pretreatment of trench base before construction in rainy season

Before the construction of the carat pipe in the rainy season, it is first necessary to do a good job of drainage and anti-backflow treatment of the trench. Pile no less than 30cm of water retaining ridges on both sides of the trench in advance, and set up a temporary catchment pit every 20 meters at the bottom of the trench, with a submersible pump to pump and drain the stagnant water at any time. All the floating soil and silt at the bottom of the trench that has been soaked in rainwater should be removed, and 10-15cm thick graded sand and gravel should be replaced and tamped to the designed bearing capacity. The flatness error of the base layer should be controlled within ±10mm to avoid deformation of the subsequent pipeline due to uneven local

Quality control requirements for carat tube laying stage

Before running the pipe, it is necessary to review whether the stiffness selection of the carat pipe ring meets the current load requirements of the buried depth and groundwater level, check whether there are bumping cracks on the outer wall of the pipe one by one, and replace all the sealing rubber rings soaked in rainwater to avoid interface leakage. The laying process should be tested with the laying, and the deviation of the pipeline axis should not exceed the design specification requirements. Every 3-5 meters of laying should be fixed with prefabricated sandbags to prevent the displacement of the pipe body due to the initialization of rainwater. Temporary plugging should be done for the nozzles that have not been connected to prevent mud from entering the lumen.

Backfill material selection and stratification operation specification

It is strictly forbidden to use collapsible loess, silt and other materials with excessive moisture content in backfilling in the rainy season. Graded crushed stone, gravel or stone chips are preferred. The moisture content of the material needs to be tested before backfilling. If the moisture content exceeds the optimal moisture content by more than 3%, it should be dried or replaced. The backfilling operation should be carried out in layers, and the thickness of each layer should not exceed 200mm. The axillary corner of the pipeline needs to be compacted with manual hand-held tamping tools. It is forbidden to directly roll heavy machinery within the range of 50cm above the top of the pipe. The compaction degree should be controlled at 85% -90%. After exceeding 50cm, normal mechanical compaction can be used. The backfilling operation should try to avoid the rainfall period. The backfilling part on the same day should be compacted on the same day, and the surface layer should be made of 2% gentle slope to

Protection points of finished products after construction

After the backfill is completed, a clear sign should be set above the pipeline. Heavy vehicles should be prohibited from passing above the top of the pipeline within 7 days. The data of the pipeline settlement observation point should be regularly reviewed. If there is settlement beyond the allowable range, the cause should be investigated in time. After the rainy season, the water closure test should be carried out uniformly, the sealing of the interface should be reviewed, and the follow-up process can be handed over after confirming that there is no hidden danger of leakage.