Sealing inspection of pipes
The sealing test of steel belt reinforced POLYETHYLENE spiral bellows should be carried out after the bottom of the pipe and the base axillary foot is backfilled with sand, and the closed water test method is used for the experiment. Fill the pipe with water to maintain the pressure of 2m head above the pipe *, and observe the leakage of the pipe for 24 hours to meet the requirements specified in Code for Construction and Acceptance of Water Supply and Drainage Pipeline Engineering CJ/T225-2011. When the conditions are available, the closed air test can also be used.
The specific steps are as follows:
(1) After the groove is backfilled to the design elevation, the initial deformation of the vertical diameter of the pipeline shall be measured within 12h to 24h, and the vertical diameter deformation rate of the pipeline shall be calculated, and the value shall not exceed 2/3 of the allowable deformation rate of the pipeline diameter. When the deformation is large, measures should be taken to correct it in time until it meets the requirements.
(2) Dig the trench backfill soil to expose 85% of the pipe height. Manual excavation must be used within 0.5m above the pipe * to check the pipe, and damaged pipes should be repaired or replaced;
(3) Re-tamp the backfill material at the bottom of the pipe;
(4) Use appropriate backfill materials and backfill compactness as required.
(5) The initial deformation rate consistent with the vertical diameter of the pipeline.