The manure is the part of the excavation for providing the working surface. For the pipeline inspection well, it is the space between the outer wall of the well and the side of the foundation pit. The space is divided into two blocks: one is the space below the pipe and the other is the rest. The latter because of tamping compaction operation condition is better, in recent years, with 6% dust layer tamping, the quality is better, this paper will not discuss mainly about the former.
In engineering practice, sometimes the construction quality of backfill is not effectively controlled due to factors such as neglect of managers, technical failure and on-site supervision and inspection. The harm caused by this is: empty under the tube body, the soil below can not form close contact with the pipe body, and can not form effective support to the pipe. In this part, the road structure of the upper part of the road is spread to the pipeline structure, the constant load of the road structure and the driving live load are completely borne by the pipe structure. Both ends of the pipeline are inspection wells solid and undisturbed soil, the pipeline structure of the actual stress state is equivalent to a "short beam", has great shearing force and bending moment in the pipeline internal structure, limit over pipeline, pipeline structure caused by cracking, damage or excessive plastic deformation, loss use function of normal pipeline, Water Leakage appear serious phenomenon. If the leaking phenomenon is not found and repaired in the short term, and the poor soil erosion resistance such as sand and soil around the pipe is very poor, it is easy to form a serious secondary damage to the road surface under the underneath of the roadbed.
Therefore, in the process of construction, effective measures must be taken to strictly check and check, and ensure the quality of backfill treatment of the fertilizer tank, which is of great significance for ensuring the safe and normal use of the pipeline structure and the safe use of the whole road project. In this regard, the relevant standards have also been stipulated. "Seventh points for construction notes" in the general description of "02S515 drainage well inspection atlas": "if the branch and dry pipe foundation fall into the well chamber, the fertilizer tank must be disposed. Its approach: the use of graded gravel, concrete filled."
In the construction process of the fertilizer trough of Yongning North Road, we use graded sand to backfill, and the quality is better. Of course, the situation permits, there are two main types: a good practice, well after completion of masonry wall to the pipe base elevation, vertical side pouring concrete pipe to pipe, flat base, and then continue to build well; two, the first row tube in place, immediately after pouring the concrete filled tube below, and fully vibrating ensure filling. |
