施工质量问题剖析与防治 Analysis and prevention of concrete drainage pipe construction quality problems
The excavation of the pipeline foundation trench shall be constructed strictly according to the requirements of the code, and the support for the concrete pouring of the foundation shall meet the requirements. Cement concrete mixing uses mechanical mixing, the material gradation is correct, and the water-cement ratio is controlled. When pouring concrete in the dry season, the water-cement ratio should be reduced, the slump of the mixture should be strictly controlled, and rain prevention measures should be prepared. Do a good job of quality inspection for each process, and rework it if it has not reached the specified width and thickness.
The quality of the drainage pipe laying not only affects the function and service life of the pipeline itself, but also directly affects the integrity of the road and environmental protection requirements.
Concrete pipe construction workers are now analyzing some common quality problems in the drainage pipe laying and propose prevention measures.
First, the root of the pipeline
1. After the concrete of the bottom layer of the pipe is poured, it arches, cracks or even cracks.
2. The sidelines are not straight, and the width, thickness, and strength do not meet the planning requirements.
3. The flat foundation is not cleaned before the pipe is installed, and there is no chisel before the pipe base is poured.
1. The soil at the bottom of the trough is soft, high in water content, and washed away by groundwater, spring eyes, and sewage.
2. The strength of concrete is insufficient, the strength of the foundation is insufficient, it does not meet the planning requirements, and the age of concrete curing is insufficient.
3. The base of the pipeline passes through the seismic cracking zone and the foundation is a liquefiable land section.
4, excavation operation does not pay attention to trimming, the lack of groove bottom width. Mechanical excavation is used to easily form kinks or different widths.
5. The measurement and release staff showed errors in their work.
(Three) prevention measures
1. The excavation of pipeline foundation trenches shall be constructed strictly in accordance with the requirements of the code, and the support for the concrete pouring of the foundation shall meet the requirements.
2. Mechanical concrete mixing is used for cement concrete mixing, the material gradation is correct, and the water-cement ratio is controlled. When pouring concrete in the dry season, the water-cement ratio should be reduced, the slump of the mixture should be strictly controlled, and rain prevention measures should be prepared. Do a good job of quality inspection for each process. Rework should be done if it does not reach the specified width and thickness.
3. In case of poor soil quality and high groundwater level, it is necessary to adopt artificial precipitation method or repair the well point system. When the water level drops below the bottom of the trough, pour concrete from the beginning.
4. Partial repair should be carried out when the concrete in the root bottom is arched and cracked. After washing the chiseled seams, the concrete with a higher strength grade should be poured.
Leakage at the pipe joint
When the drainage pipeline is delivered for use, the leakage of the pipeline interface will cause the cover soil layer to be lost, resulting in settlement, pipeline cracking and other phenomena.
1. When the concrete receiving pipe is arranged, the socket is not full. The mix ratio of the mortar used does not meet the requirements and the strength is not enough, but the use time has exceeded 45min.
2. The pipe connection is not sufficiently wet and cured. The concrete pipe itself is of poor quality.
3. Because the construction unit is not strict, the supervision is not strict, and all or individual spare pipes are missed and not blocked.
(Three) prevention measures
1. Strict inspection is necessary for all pipes, especially after unloading, check for damages, cracks, and defects in the nozzles. The above problems should be removed when found.
2. For those who choose a rigid interface, use clean water to wash the nozzle and keep it moist. The burrs should be chiseled, and the mix ratio of mortar or fine stone concrete used should meet the planning requirements.
3. If cracks, crusts, drops, etc. are found, go to the beginning and follow the procedure after starting.
4. The quality inspectors and as-built inspectors should pay attention to inspection and make up for the gaps.