1. Construction Preparation: Conduct a detailed survey of the terrain, geology, and underground pipelines along the pipeline route. Prepare pipe materials, fittings, and manhole materials that meet design requirements. Assign professional technicians and construction personnel, and prepare construction equipment such as excavators, cranes, and ramming machines.
2. Surveying and Setting Out:
* Based on the design drawings, determine the pipeline centerline and manhole locations. Set temporary benchmarks and control stakes to ensure measurement accuracy meets specifications.
3. Trench Excavation:
* Determine the trench cross-section: Based on the pipe diameter, burial depth, and soil conditions, determine the trench width, depth, and slope. Generally, when the trench depth is less than 3 meters, the slope is 1:0.3; when the trench depth is greater than or equal to 3 meters, the slope is 1:0.5.
4. Foundation Construction: Clean up debris and silt from the bottom of the trench. Replace, compact, or reinforce weak foundations to ensure the foundation bearing capacity meets design requirements.
5. Pipeline Installation
* Pipe Selection and Inspection: Pipes are laid mechanically or manually, and joints are connected.
6. Manhole Construction
* Manhole foundations are made of poured concrete, typically 150-300 mm thick. A bedding layer is added if the soil bearing capacity is insufficient.
7. Water Tightness Test
Both ends of the test pipe section are sealed to ensure the pipe and manhole appearance are up to standard, there is no water accumulation in the trench, and the pre-drilled holes are tightly sealed. Then, water injection, soaking, and seepage observation tests are conducted.
8. Trench Backfill
* Backfill material: Medium-coarse sand or gravel is used for backfilling from the bottom to 0.5 meters above the top of the pipe. Plain soil can be used for backfilling above 0.5 meters above the top of the pipe.
