As a professional engineer, in terms of PE pipe construction, you must be very clear about the construction process. Here we will share the PE pipe construction technology. This article mainly describes the first part of the construction process: engineering construction survey, testing method, construction method of trench excavation, pipeline foundation, PE pipe connection operation method and masonry of well chamber.
Construction Plan and Technical Measures
1. Water Supply Engineering Construction Survey
- Measurement and setting-out: Design the construction site measurement sketch according to the coordinate points and elevation points handed over by the construction unit.
- Lead the control coordinate points to the construction site, mark them and protect them.
- Introduce the control points of the measuring tool according to the requirements of the engineering characteristics.
- Place the centerline and sideline of the construction trench.
- Measure the bottom elevation of the tube.
- Measure the elevation of the bottom of the middle room.
2. Testing Method
- Use Jing Wei instrument to encrypt the center pile of the road according to the coordinate points handed over by Party A. Set up a control pile every 150m and protect it. Use a level to measure the elevation to nearby buildings and make obvious marks.
- Adopt the direction method with a ruler to determine the trench excavation sideline. And use white ash to scatter the excavation line.
- After the trench is excavated, set up the gantry piles. Using wood planks to measure the centerline and elevation of the pipeline on it with a spacing of no more than 35m.
3. Construction Method of Trench Excavation
- The trench excavation adopts small-scale mechanical excavation and manual slope repair. The excavation slope is 1:1. The soil for the trench excavation is stacked to the north. And the distance between the soil pile and the excavation sideline is not less than 1.5m. Excavate the bottom soil layer to ensure that it will not be moved. About 20cm of protective layer should be reserved for trench excavation, which should be cleaned manually.
- When digging trenches, protect them if there are pipelines and cables. And report to relevant units in time to solve them in time to prevent losses from accidents.
- The soil layer of the excavation trench should be solid. If it encounters loose backfill soil, humus soil or stones, etc., it should be treated. The loose soil should be excavated and refilled. The thickness of the backfill should not exceed 20cm for rolling. Excavate and replace sand and gravel materials and compact them. In case of stones, clean up the existing sites and replace them with better soil for backfilling.
- In the process of trench excavation, the bottom elevation and center line of the trench should be monitored and controlled at any time to prevent over-excavation or deviation.
The allowable deviation of the groove should meet the requirements of the following table
|Allowable deviation of trench excavation|
|NO||ITEM||allowable deviation(mm)||Inspection frequency|
|1||Elevation of the bottom of the tank||－3～0||Between the two wells||3|
|2||The width of each side of the center line of the bottom of the groove||Not less than the specified||Between the two wells||6|
|3||The slope of the groove side||Not less than the specified||Between the two wells||6|
4. Pipeline Foundation
- Only after the trench excavation has passed the acceptance check can the pipeline foundation construction be carried out.
- Adopt DN315PE pipe, hot-melt interface and sand-gravel foundation.
Water Supply Pipeline Construction Process: Pipeline measurement → pipeline clearing → construction of access roads → pipe trench excavation → PE pipe transportation → construction sand cushion → PE pipe hot melt connection → pipe laying → pipe body backfilling → pipe section pressure test → valve and well room installation → pipe trench Backfill→set pipe marking→water test
5. PE Pipe Connection Operation Method
The connection interface of the thermal fusion butt joint is flat. The method is to heat the two identical connection interfaces with a hot plate to a viscous flow state, remove the hot plate. And then apply a certain pressure to the connection interface. The last is cool and solidify under this pressure state to form a strong connection. For the details please view How to Weld and Install PE Water Supply Pipe?
6. Masonry of Well Chamber
- Place the baseline before the well chamber is built. The baseline must be accurate. The position must not be deviated, and the geometric dimensions must be accurate.
- During the well foundation construction, no water should be carried. And water should be dewatered when necessary to ensure that there is no leakage after the bottom of the well is formed.
- The masonry shaft wall is full of mortar, the mortar joints are flat, and there must be no joints. Each layer must be filled with joints, and brick wedges must be clamped. Do a good job in the waterproofing of the well chamber, so that it can be wiped as soon as it is laid. The inner and outer walls of the well shall be plastered with 1:2 waterproof mortar, with a thickness of 15mm,. It should pay attention to maintenance. Plastering shall not have hollow drums or cracks, and the well chamber shall be calendered and polished.
- The installation position of the ladder in the well chamber is accurate. The installation is firm and the verticality of the line is corrected.