Construction method of PE pipe in municipal water supply and drainage project

PE pipe in the municipal water supply and drainage projects are mainly divided into trenching and non-excavation type of two types of construction methods, today PE pipe manufacturers mainly from the following main trenching construction methods to elaborate.

(1) the first construction should be in accordance with the relevant provisions of the norms of pipe laying, and in accordance with product standards for inspection, eliminating non-standard pipe. If the pipe is laid under the carriageway, the top of the pipe cover thickness should not be less than 0.7 meters. If it is necessary to cross the obstacles, it is necessary to set up the protective casing made of steel bars and so on. Pipeline laying should be in accordance with the straight line construction, if it is necessary to use flexible interfaces folding line laying, connected to the longitudinal axis of the pipeline should not be more than 2 ° angle. When the depth of the pipeline is lower than the base of the building foundation, the pipeline should not be laid in the building foundation under the foundation diffusion angle within the pressure zone. When the groundwater level is higher than the excavation trench bottom elevation of the region, the construction should be taken to reduce the groundwater level measures to prevent trench destabilization, in the installation of the whole process of backfilling, should pay attention to the bottom of the trench is not water or soak the groove is frozen.

(2) According to the external environment under pressure, it is appropriate to use different rigidity of PE pipe.

(3) When excavating the trench, the width of the bottom of the PE pipe trench should be reasonably determined first, in line with the construction regulations, in order to carry out manual work. The construction process shall not over-excavate the trench, if accidentally over-excavated, it is appropriate to use natural grading sand and gravel material for filling, filling of sand and gravel particle size should be between 10mm-15mm, or the maximum particle size is less than 40mm.

(4) Pipeline foundation using sand bedding foundation, should be reserved in the interface part of the groove, so that the interface operation, interface construction is completed with sand landfill. For the general soil base is only a layer of 0.1M thickness of sand bedding. If it is a soft ground and the bottom of the trough is located under the water table, it is appropriate to lay a layer of gravel foundation with a thickness of not less than 500px.

(5) in the lower pipe installation construction, should be trenching after the slot width, depth of the groove, foundation surface elevation, check wells and other aspects of strict inspection to ensure that the work items in line with the construction requirements and regulations before proceeding to the next step in order to improve the quality of construction.

(6) After the inspection, the next step is the connection and installation of PE pipes. Manual installation methods for the installation of non-metallic rope should be used to slip the pipe, so that the pipe is placed smoothly on the gravel foundation. Socket pipe installation order should generally be socket in the direction of water flow, socket against the direction of water flow, and from low to high installation order. When carrying out the interface process, first of all, the two sides of the mouth should be cleaned and coated with lubricating oil, coated with a good alignment of the center line waiting to be connected. Pipes and inspection wells can be connected using the intermediary layer approach to connect the two connected parts of the pipeline in advance with a good bonding with the pipe plastic adhesive and coarse sand for the intermediary layer, and then 1:2.5 cement for the connection, and then mortar into the wall of the inspection wells, so that the wells and tubes to join between the dense, smooth flow grooves at the bottom of the wells with the pipe wall joints, the mouth of the pipe and the well wall is flush.

(7) PE pipe installation should be strictly inspected after completion, such as the inspection is qualified to start trench backfill, trench backfill, pipe bottom to pipe top 1750px within the scope of manual backfill must be used, 1750px or more can be used to backfill the mechanical backfill. When backfilling, make sure there is no debris in the trench. In addition, the compaction of backfill should not be less than 95% of the thoracic part, the top of the pipe more than 500mm should not be less than 80%, and other parts of the pipe should not be less than 90%. Attention should also be paid to the selection of tamping equipment to avoid damage to the pipeline structure during construction.