Familiar with design drawings and materials, and clarify the pipeline layout, direction, process flow and construction installation requirements of the main pipe and branch pipe. Familiar with the scene and understand the distribution of the existing plane and elevation control points along the design pipeline. According to the pipeline plane and the existing control points, combined with the actual terrain, the measured data is sorted and the actual survey sketch is drawn.
After entering the site, the leveling point and the conductor point handed over by the construction unit are re-tested. After the closing difference meets the design requirements, the wire point and the leveling point are encrypted. There is a leveling point within every 60 meters. The encryption point must be closed. The closing difference of the leveling point is 20√L, ensuring the accuracy of the encryption point to meet the accuracy of the drainage pipe elevation and line type control.
Since the piles in the pipeline are to be dug during construction, the piles are controlled in the place where the construction is not disturbed, the measurement is convenient, and the protection is easy. The piles are controlled in the middle direction, and the extension line or the wire method is used. The position control pile of the structure adopts the intersection method or the parallel line method.
The measurement during the construction process is mainly the determination of the elevation of the bottom of the tank. After the mechanical excavation, the machine is used for measurement. With the excavation and measurement, the over-excavation phenomenon is eliminated, and the elevation of the bottom of the tank meets the design requirements. After the pipeline is installed, the re-test is carried out and found. The problem is dealt with in a timely manner so that the bottom elevation of the tube is within the allowable deviation range. Adjacent level review measurements are taken before the daily measurement work begins.
The center of the pipeline is determined by the central control pile. The control pile is used to draw the edge on the pipeline to determine the laying position of the pipeline.
The well chamber elevation is controlled according to the design requirements. After the pipeline is laid, the completion and measurement of the pipe roof and structures shall be carried out.
Trench excavation and basic treatment:
Familiar with the drawings, according to the design of the benchmark points and coordinate control points for measurement, positioning, release, lead temporary level points and control piles, after the supervision engineer's review and approval, the trench can be excavated.
The excavation is carried out by the excavation. The trench excavation must strictly control the depth of the excavation and the centerline of the pipeline. The mechanical excavation should leave a margin of 20cm, from the manual clearing to the design of the trough height of the trough, and lead the mileage pile to the bottom of the trough. .
Strictly control the groove excavation and grading coefficient, and dig the width according to the designed grading coefficient. When excavating, pay attention to the groove soil condition. If necessary, please ask the resident supervisor and Party A and the design representative to determine the grading coefficient on site to prevent The rim collapses.
The earthwork of the trench excavation is directly loaded and transported by the owner, and the place of the outbound transportation is designated by the owner.
When there is groundwater in the trench excavation, set up drainage ditch and water collecting pit, timely do the drainage and precipitation work of the groundwater in the trench, and adopt the foundation reinforcement measures of paving gravel or gravel layer (thickness not less than 100mm); When there is no groundwater, the soil is compacted under the foundation, and the compaction coefficient is greater than 0.95. When there is a weak foundation such as silt or miscellaneous fill, the graded Gobi soil is used for the replacement treatment according to the pipeline treatment requirements; the replacement fill thickness is 30cm.
After the trench is excavated for about 100 meters, the earthwork is transported by the artificial clearing tank, and the inspection is passed by the supervision engineer before the next process can be carried out in the trench.
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