Construction scheme of reinforced concrete circular pipe culvert
1, construction method and construction technology
1. 1 construction process:
Construction preparation → construction lofting inspection → foundation excavation → sand cushion construction → foundation concrete pouring below the pipe bottom → pipe joint installation → foundation concrete pouring below the pipe bottom → pipe joint head construction → settlement joint treatment → entrance and exit construction → foundation pit backfill soil → completion acceptance.
1.2 Main construction methods and technologies
1.2. 1 Foundation excavation is open-cut foundation. If the culvert foundation is located on the dredged fill layer, the dredged fill should be carried out before the culvert construction, and the circular pipe culvert should be excavated for the second time after the fill height at the top of the culvert is greater than 0.5.
Excavators and 10T dump trucks are used for foundation pit excavation, and the foundation is cleaned manually. Firstly, the foundation pit is excavated by excavator, and the earthwork of the foundation pit is directly transported away from the construction site by dump truck for subgrade construction or soil abandonment. When the excavation is close to the basement elevation, manual excavation is adopted. The purpose of manual excavation is to vertically cut the earthwork around the foundation pit along the excavation scope line, and at the same time manually excavate the foundation pit to the design elevation. Then mechanically or manually tamp the bottom of the foundation pit. Finally, it is reported to the supervision engineer to check the bearing capacity of the basement, the plane size and elevation of the foundation pit, and the next foundation construction can be carried out only after the on-site supervision engineer has passed the inspection.
1.2.2 The foundation macadam cushion shall be watered manually, tamped by vibration rammer and leveled by flat vibrator.
1.2.3 surveyors carefully and accurately set out the longitudinal and transverse axes of the culvert on the top surface of the cushion, then spread out the edge line of the culvert foundation with white plaster, fix it around it with wooden stakes, and protect the wooden stakes with cement concrete to prevent constructors from colliding with the wooden stakes during construction, and encrypt the leveling points near the structures. Before pouring the foundation, determine the position of settlement joint according to the length of culvert and the width of cover plate to ensure the consistency of plate joint and settlement joint when the cover plate is installed. Settlement joints are set every 4 ~ 6 meters, so the foundation formwork is installed in sections, which are located at the settlement joints. The foundation formwork is made of steel formwork, which is assembled by manual pulling on site, and the inner surface of the formwork is coated with release agent; The flat joints between formwork surfaces are tight, and there is no slurry leakage. A fulcrum is fixed outside the template. After the template installation, the quality inspector shall check the elevation, verticality and support firmness of the top template size, and check the template, make records, and report it to the supervision engineer for inspection after passing the self-inspection. After inspection, concrete can be poured.
The foundation concrete is mixed centrally in the mixing station. Before the concrete comes out, the tester will do slump test and extract the test form as required. After passing the test, it will be transported to the construction site by concrete truck, poured by chute, and the uniformity and slump of concrete will be checked. After passing the test, it can be poured into the template and vibrated with an internal vibrator. The moving distance of the vibrator shall not exceed 1.5 times the vibration radius; Keep a distance of 50~ 100mm from the side formwork; Avoid the vibrator colliding with the template; After each vibration, slowly lift the vibrator out while vibrating; For each vibrating part, the concrete vibrated to that part is dense. The sign of compactness is that the concrete stops sinking, there are no more bubbles, and the surface is smooth as slurry. When pouring concrete, fill in the concrete construction record. Cover with sanitary cloth after pouring, and sprinkle water for health after final setting. The curing period shall not be less than 14 days. The foundation concrete is poured twice. First, erect side formwork to pour the part below the pipe bottom, then hoist the part above the pipe bottom, and adjust and fix it. The concrete of pipeline foundation should be straight and the thickness should meet the design requirements.
1.2.4 The pipe joint is a prefabricated standard, transported to the site by car, hoisted in place by 8t truck crane, and the pipe culvert joint is butted. The gap between the pipe joints is filled with asphalt hemp wool, and the outer side is wrapped with three circles of linoleum coated with hot asphalt.
1.2.5 settlement joint fabrication: settlement joint fabrication shall be carried out in accordance with the specification requirements. Two adjacent joints at the settlement joint shall be vertical and smooth, and there shall be no twists and turns.
1.2.6 The entrance and exit are built with 7.5# mortar rubble, and the cap stone is made of 20# concrete. Masonry construction adopts slurry squeezing method. During construction, ensure that the mortar label meets the design requirements, the jointing mortar is full, the wall surface of the splayed wall is flat, the lines are angular, the jointing meets the requirements of the construction specifications, and the jointing is beautiful.
1.2.7 Backfilling of culvert foundation: Backfilling shall be carried out after inspection and confirmation by the supervision engineer, and the culvert foundation concrete and pipe joint mortar must reach more than 80% of the design strength during backfilling. Both sides of culvert shall be backfilled symmetrically in layers. The backfill material for culvert foundation pit excavation should be permeable gravel, and the degree of compaction should be above 93%. The fill behind abutment should be fully compacted, the compactness should reach more than 96%, and the internal friction angle should not be less than 35 degrees.
2, construction matters needing attention
(1) Before construction, carefully check the coordinates, pile number, elevation, culvert intersection angle and culvert length of each culvert. If in doubt, please contact the design unit in time.
(2) If you find that the geological conditions provided by this design are inconsistent with the actual situation during the construction, please contact the design unit in time.
(3) The construction must be carried out in strict accordance with the working procedure and in comparison with relevant drawings.
(4) During the construction, when the thickness of the top fill of culvert is less than 0.5m, it is forbidden for any heavy machinery and vehicles to pass through, and it is not allowed to be rolled by vibratory roller.
(5) If it is necessary to damage the subgrade, pavement, ditches and ancillary facilities of the original road during the construction, it shall be restored in time after the construction.
Conclusion: The above contents are detailed construction scheme and construction precautions of reinforced concrete circular culvert. Reinforced concrete circular culvert is a very important project in building engineering, and the construction personnel should strictly follow the scheme steps to grasp the quality of building engineering. At the same time, the construction unit should also pay attention to the matters needing attention in the construction process, so as to ensure the project quality and the personal safety of the construction personnel and avoid the occurrence of construction accidents.
Tubatu Online provides you with "every decoration quotation, 1-4 local decoration companies, 3 sets of decoration design schemes" and the decoration pit avoidance strategy for free! Click this link:/Zhu Ye /zxbj-cszy.php? to8to _ from = SEO _ zhidao _ m _ jiare & amp； Wb, you can get it for free ~