1. Poor foundation conditions of the pipeline will cause uneven subsidence of the pipeline and the foundation, usually forming part of the water, and in severe cases, the pipeline will crack or the interface will crack. The following precautions should be taken:
1) Carefully construct according to the design requirements, the strength and stability of the pipeline foundation. When the local foundation geology and hydrological conditions are not good, soil replacement should be carried out to improve the treatment to improve the bearing capacity of the bottom of the foundation trench;
2) If the soil at the bottom of the tank is disturbed or soaked in water, the soft soil layer should be excavated first, and then the over excavated part should be backfilled and compacted with materials with good stability such as sand or gravel.
3) When excavating earthwork below the groundwater level, effective measures should be taken to do a good job of drainage and dewatering at the bottom of the foundation trench. During dry trench excavation, a soil layer with a thickness of 20cm to 30cm can be reserved at the bottom of the trench, and it will be closed with the excavation during the subsequent construction.
2. The amount of pipe raw materials is poor, there are cracks or the concrete on the pipe wall is loose, the impermeability is poor, and water leakage is easy to occur.
3. The filling and construction quality of the pipe interface is poor, and the interface is cracked under the action of external force. The preventive measures are as follows:
1) Select the interface filler of excellent quality and arrange the construction according to the experimental mix ratio and reasonable construction technology.
2) The joints should be clean, and the cement filler joints should be pre-wetted, and the oily ones should be pre-dried and then brushed with cold root oil, and then carefully constructed according to the construction operating procedures.
4. The construction quality of the inspection well is poor, and the wall of the well and its connections are leaking. Its preventive measures:
1) Check the well masonry mortar should be full, the joint should be all, not lost;
2) The outer surface of the pipe that is continuous with the inspection well should be wetted and evenly brushed with a cement mortar, and then the outer surface should be plastered after the slurry is in place to prevent leakage.
5. The sealing of the closed water section is not tight, and it is often ignored because it is in the well. If you choose a brick wall for sealing, you should pay attention to the following points:
1) Before blocking, the inner wall of the pipe within a range of about 500 ram should be cleaned, and the cement paste should be painted together, and the bricks used for blocking should be fully moistened;
2) The strength of the plugging mortar should not be lower than M7.5, and should have a good consistency;
3) The strength of cement mortar used for jointing and plastering should not be lower than Ml5. When the diameter of the pipe is large, it should be plastered on both sides of the surface, and when it is small, only single-sided jointing or plastering can be done. The plastering surface should be constructed according to the five-layer construction method;
4) When conditions permit, sealing and masonry can be carried out before the inspection of the well masonry to facilitate the quality;
5) The preset drainage hole should be located at the inner bottom of the pipe for viewing during draining and testing;
6. The closed water test is to check all the pipeline construction and material quality, during which three or two unqualified phenomena will inevitably occur. At this time, symbols should be made one by one at the leakage, and careful disposal should be carried out after draining the water in the pipe. Do the experiment after treatment, and repeat until the closed water is qualified.