Key points in the process of FRP pipe laying

1、 The bottom of the GRP pipe trench is uneven, and there are sharp hard s such as hard soil blocks and stones blocking the pipeline. Generally speaking, the pipe trench in low-lying areas is excavated mechanically. Due to the low terrain, the bottom of the pipe trench is wet or filled with water, and there is a great possibility of hard s, mainly gravel, bricks and obstacle pipelines. Especially when the water volume on the pipe trench is large, these hard s are not easy to be found when they exist below the water surface. When the GRP pipe is directly backfilled after being installed on the water surface, the GRP pipe is directly pressed on the hard , which may not be damaged in a short time due to the looseness of the backfill soil, but due to the settlement and compaction of the backfill soil, after the pipeline is put into operation, the internal pressure effect of the pipe and the internal liquid flow cause the micro-vibration of the pipe. With the increase of time, the point load effect of the hard on the GRP pipe is becoming greater and greater, The point where the glass fiber reinforced plastic is affected by hard s will be damaged. In addition, the uneven bottom of the pipe trench will cause uneven stress on the pipeline. When backfilling, the high places will produce stress concentration. Damage to pipes or cause unnecessary wear. When there is pulsating pressure in the pipeline system, the wear is more serious.

2、 A large amount of accumulated water and collapse in the pipe trench. The construction of surface works usually catches up with the rainy season. Due to the low-lying terrain of the construction section, the water inflow after the excavation of the pipe trench is large, and the deep section can reach more than 1.0m. Due to the light weight of high-pressure glass fiber reinforced plastic pipe, all pipes will float on the water after being installed in the trench. Due to the buoyancy of water, it is difficult to press the GRP pipe into the bottom of the trench with soil during backfilling, which causes the buried depth of the pipe to fail to meet the design requirements. In addition, because there is too much water in the trench, it is difficult to grasp the flatness of the trench bottom, and it is also difficult to see whether there are obstacles, pipelines, gravel and other hard s at the trench bottom, and it is difficult to ensure the construction quality of GRP pipes. The accumulated water in the pipe trench in the low-lying area is easy to cause the collapse of the pipe trench, and the collapsed massive earthwork will often directly hit the glass fiber reinforced plastic pipe line and damage the pipeline.

3、 The impact force of hard s such as stones and mechanical backfill in the backfill of pipe trench. The backfill in low-lying areas is relatively wet, and some of them are basically in the state of mud. In the process of backfilling, if the mud is mixed with hard s such as stones, it is difficult to be found. These stones are buried at the bottom of the trench and directly contact with the FRP pipes, which will pose a great danger to the FRP pipes. It is also possible that in the process of backfilling, due to the large size of rocks, the GRP line will be directly damaged under the impact of gravity. During mechanical backfilling, the full bucket of soil will be directly backfilled into the trench from a high place, and the pipeline will also be damaged due to large impact force.

4、 Other factors, such as non-standard operation of construction personnel. During the construction, due to the harsh construction environment in low-lying areas, the construction personnel did not operate according to the specifications. For example, when the pipeline was connected, the muddy water in the threaded part was not wiped clean, the thread was not screwed into the depth enough, and the water, mud and other debris in the pipeline. In addition, the construction personnel throw tools casually, which is particularly easy to break the GRP pipe. These details are hidden dangers in the construction of high-pressure FRP pipes.