The construction process of steel corrugated pipe culvert is shown in the following figure.
Construction preparation measurement lofting foundation excavation foundation bearing capacity detection basement treatment foundation construction integral pipe joint assembly connection I-wall construction culvert abutment backfill material inspection and acceptance construction lofting leveling construction site, arranging various material stacking sites and sorting out required mechanical equipment. Before construction, organize surveyors to set out the axis of pipe culvert according to the design documents, lay out middle piles, sprinkle white lines on the axis of pipe culvert and the edge of foundation range, and measure the original ground elevation.
After lofting,
According to the specific geographical conditions of the construction site and the construction site, the relevant water systems will be diverted, converged and drained to the outside of the working face to prevent soil leakage from eroding the bearing layer of culvert foundation.
Foundation excavation (1) shall be carried out according to the design requirements. In order to facilitate mechanical rolling, the standard width of foundation is adopted.
(2) After the temporary drainage is completed, clear the topsoil of the construction site, connect the temporary service road, and then carry out earthwork excavation. During the excavation, the mechanical excavation elevation will be controlled at 20cm above the design basement elevation.
(3) After the foundation pit excavation is completed, the bottom shall be cleared manually to the designed basement elevation in time. The soil foundation pit dug to the elevation shall not be exposed, disturbed or soaked for a long time, and the size, elevation and basement bearing capacity of the foundation pit shall be checked in time. If the bearing capacity of in-situ foundation meets the design requirements, it shall be reported to the supervisor in time for foundation trench inspection; When the self-inspection finds that the bearing capacity of soil foundation does not meet the design requirements, it shall report to the supervisor, design representative and owner's office in time, put forward the basement treatment scheme and change the foundation design.
4) The culvert foundation trench must be strictly compacted (the compaction density is greater than 96% of the heavy compaction density). The culvert foundation filled with foundation cushion must have sufficient strength, stability and uniformity. The foundation is gravel, and a uniform cushion with a thickness of 30cm should be set on the surface of the foundation with well-graded coarse sand. Its maximum particle size is12 mm. The compactness of foundation cushion shall not be less than the specification requirements. When filling the foundation, it should be filled by layers and compacted by layers. The compaction thickness of each layer is 20cm. Only after the compactness meets the requirements can the next layer be filled.
Build.
Preparation before pipeline installation (1): Prepare installation tools, accessories required for installation, hoisting equipment, socket wrench, constant torque electric wrench, constant torque wrench, and sufficient equipment such as feet, springboard and power supply. Check whether the length and diameter of each joint of corrugated pipe are consistent with the culvert, and set up a culvert installation commander, who is responsible for directing the hoisting and construction personnel to operate on site.
(2) Pre-installation: Check the setting of foundation flatness, elevation and foundation pre-camber at the bottom of culvert, and determine the location, central axis and midpoint of culvert. The pipe body shall be installed close to the gravel cushion, so that the stress of the pipe culvert is uniform, the slope of the top surface of the foundation is consistent with the design slope, and the pre-camber of the pipe body along the transverse direction is 0.2%- 1% of the length of the pipe joint, so as to ensure that there is no sag or reverse slope in the middle of the pipe.
(3) Connecting and installing steel corrugated pipe: according to the actual situation, discharge pipe culvert. During installation, let out the first pipe joint from one side, so that its pipe center is parallel to the longitudinal center line of the foundation, and the second pipe is also in place. When the distance between adjacent flanges of two pipelines is 3 ~ 5 cm, align the bolt holes on the flanges with a small crowbar to align the bolts on the flanges of two pipelines. At this time, pry the pipe joint from the other end of the second pipe with a crowbar to move it longitudinally to the culvert. When the distance between the two flanges is 2 cm, insert each bolt into the screw hole.
(4) Insert gasket: Due to the site topography and other reasons, sometimes the distance between two adjacent flanges is small. At this time, use a hammer and chisel to cut a gap of about 1cm between the two flanges, and use a screwdriver to insert the gasket between the two flanges. Sometimes the distance between the two flanges at the top of the pipe joint is large, so it is difficult to insert the gasket. Then the workers began to tighten the nuts symmetrically.
Until there is only a gap of 2 ~ 5 mm between the two flanges when viewed from the outside.
(5) Tighten the nuts: after all the assemblies are completed, tighten the nuts one by one. The torque of each nut should not be less than 135.6N? M, the maximum shall not exceed 203.4N? M. When using an electric wrench, the pulling time should last for 2s ~ 5s.
After that, they are connected in turn.
In order to ensure that the bolt torque reaches the required value, the bolts with 2% longitudinal seam on the structure are randomly selected before backfilling, and the random inspection test is carried out with a fixed torque wrench and a fixed pre-tightening torque of 340 N m 70 N m.
If any test value exceeds the given torque range, 5% of all bolts in longitudinal and circumferential joints shall be sampled.
If more than 90% of the above tests meet the requirements, it is considered that the installation is qualified, otherwise it should be rechecked to determine whether the torque value meets the requirements.
(6) After the bolts at the lap joint of the outer ring meet the requirements, in order to prevent the water seepage of the corrugated steel plate joints and screw holes, special sealing materials are used to seal the steel plate joints and bolt holes to prevent the water seepage of the corrugated steel plate joints.
(7) Asphalt coating inside and outside the pipe wall: When the culvert pipe leaves the factory, the culvert pipe and its accessories have been galvanized. The galvanized thickness is greater than or equal to 63 microns, the average thickness is 84 microns, and the galvanized amount is not less than 600g/㎡. Under the condition that there is no saline-alkali water or harmful industrial wastewater soaking and the culvert pipe does not run frequently, its coating can prevent corrosion. Otherwise, under normal circumstances, emulsified asphalt or hot asphalt can be sprayed twice inside and outside the pipe joint. But it must wait until the asphalt is dry before backfilling.
(8) Use jack to correct the whole culvert, so that its center is located on the central axis of culvert position.
The specified value or allowable deviation of compaction degree (%) of steel corrugated pipe culvert foundation has reached the design reviewer. Axis of corrugated pipe culvert: the soil foundation under projection shall be measured once every 6m, but not less than two theodolite or stay wires: one every 6m, but not less than two level meters: one every 6m. But not less than two measurements: but not less than two pipe culvert axis deviation (mm) pipe culvert inner bottom elevation (mm) installed pipe culvert inner diameter (mm) 20 10 1% It is very important to backfill (1) steel corrugated pipes on both sides and top of the culvert, and the quality of culvert backfilling must be guaranteed.
2) Fine-grained cavity ballast shall be backfilled on both sides of culvert. Use a 25T roller to roll the pipe at a distance of 50cm from both sides of the maximum diameter of the pipe body, and use a small rammer to tamp it within 50cm to avoid the impact of large mechanical equipment such as roller on the pipe culvert.
3) Filling shall be done by layers and compacted by layers. After compaction, the thickness of each layer is 20cm, and the lower layer can only be filled when the degree of compaction reaches 94%. Before filling, both sides of the pipe joint are marked with red paint every 20cm in height, and the filling is controlled according to the marking line.
The layered thickness and compactness of fill on both sides of culvert should be strictly controlled, and special personnel should be appointed to be responsible for supervision and inspection. After the specified rolling times are completed, random sampling inspection shall be conducted, and the inspection frequency shall be every 50m2 checkpoint. When it is less than 50m2, at least check points, and each point shall be qualified. Compaction standard of filled soil is:
From the filling base or the top of culvert to the top of subgrade is 94%, and the compactness can be detected by grouting.
Sand method, if the inspection is unqualified, it should be rolled several times until it is qualified. Only after passing the inspection can the next layer be backfilled.
(4) When the thickness of the pipe top fill is less than 50cm, a roller greater than 6T shall not be used for rolling, and construction machinery shall not pass.
(5) Dynamic compactors are not allowed to be used on both sides of the pipe culvert and within 20 meters at the top.
(6) There shall be no hard objects such as stones greater than 50 mm within 0.5 meters around the pipe body. When filling, it shall be filled by layers and compacted by layers, and the compaction thickness of each layer shall be 20cm. After the compaction degree meets the specification requirements, the next layer can be filled.
The backfill must be carried out symmetrically and synchronously on both sides of the culvert, and the height difference of backfill on both sides shall not be greater than 20cm.
(7) Backfilling the culvert with end retaining wall from both ends of the culvert to the center of the structure; For culverts without end retaining walls, backfill from the center of the culvert to both ends (8) Mechanical dynamic compaction is not allowed within 20 meters of the top and sides of the culvert.
(9) From the start of backfilling to the end of filling at the top of culvert, the maximum difference between the final section size and assembly size shall not exceed 2%. If the cross-section deformation exceeds the deformation range, the construction should be stopped immediately, the reasons should be found out, and corresponding measures should be taken to control the deformation within the standard requirements.
The opening paving protection adopts end wall type or oblique mouth type with the same slope as subgrade slope. The entrance is M7.5 mortar rubble.
The longitudinal slope laid outside the hole and the hole should be the same as the longitudinal slope at the bottom of the culvert; The longitudinal slope laid outside the hole can also be determined according to the specific conditions at the bottom of the ditch, so that water can flow in and out of the culvert smoothly, and it is advisable that the variable-speed water does not cross the culvert.
(1) Construction preparation: The surveyors will set out the exact position, pop up the wall position line and put it on the wall.
Position the body to fully cut the hair and clean it up.
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