Under the traditional practice, each hole needs to be positioned separately, and the casing installation is time-consuming, which is easy to cause the position of the reserved hole to be inaccurate, affect the later pipeline installation, and cause the secondary opening and repair at the same time. 
The traditional method of pipeline well casing is labor-intensive and time-consuming, and the scientific research and design base of Gansu Provincial Water Conservancy and Hydropower Survey, Design and Research Institute and the project of Shanshui Famous Garden innovates the process, adopts the one-time pre-embedding construction technology of pipeline well casing in the main stage, and uses BIM technology to accurately model the standard layer pipeline well, optimize, position, and process the casing positioning and installation mold, and after positioning and fixing each casing, all the casing is welded and connected as a whole through steel bars, and the casing is fixed as a whole after the formwork is supported and the steel bar is tiedEach layer of standard layer pipeline well casing can be positioned and fixed with this mold. 
One-time pre-embedding construction technology of pipeline well casing.
The one-time embedded construction technology of pipeline well casing, the casing is installed in place at one time with the main body pre-embedded, which reduces the positioning process of the reserved hole of the main body, each casing of the standard layer and the link of the secondary hanging hole plugging in the later stage, and also avoids the hidden danger of water leakage that may occur in the later hanging hole, optimizes the construction process, saves artificial materials, reduces the construction cost, improves the quality of perception, and ensures the quality of the project. Process flow and operation points
01 Pipeline well modeling drawingThrough the establishment of the pipeline well BIM model, determine the professional pipeline layout scheme, in the process of arrangement, in order to ensure the overall appearance quality and later maintenance of the pipeline after installation, according to the type and model specifications of the pipeline system, from the inside to the outside for the air conditioning water supply and return pipe, rainwater pipe, self-spraying pipe, waste water pipe, fire hydrant pipe, water supply pipe, determine the position and spacing of each professional pipeline, and derive the CAD plan of the pipeline well. 
Pipeline BIM model positioning.
CAD floor plan of the pipe well.
02 Processing and production of casing reserved mold construction team in accordance with the technical disclosure of casing mold processing, according to the on-site pipe well size cutting the corresponding 3mm thick steel plate, according to the casing reserved CAD plan elastic line positioning, mark the center position of the casing, according to the outer diameter of the casing in the transverse and longitudinal vertical two diameter outside mark, in the four positions of the mark 6cm long equilateral angle steel. 
Casing overall mold processing and production.
03 Casing integral processing and production (1) According to the size of the pipeline, use a cutting machine to intercept the casing of the corresponding pipeline, and the length of the casing of the pipeline well is generally set to a plate thickness of +50mm. (2) Put the corresponding casing into the diameter of each pipeline according to the technical disclosure. 
The casing is placed in the mold.
3) Use 12mm steel bars to weld and connect all casings along the upper and lower layers of the outer ring into a whole, and weld and connect each casing with 8mm steel bars to ensure that the casing connection is reliable. 
The casing is connected as a whole.
4) Take out the overall casing from the mold, brush the anticorrosive paint on the inner wall of the casing to prevent corrosion, use a tower crane to lift the casing to the working face for installation, and prevent the overall deformation of the casing during the hoisting process. 04 Casing positioning, fixing, acceptance of the overall casing to the corresponding floor of the pipe well position, select two diagonal two casing, on the template in the center of the casing with a hole opener each 30mm hole, the two infrared level are placed in the diagonal two casing and projected to the center of the corresponding casing on the lower layer, with a level, a scale to measure whether the projected infrared light and the casing of this layer are concentric, if the deviation, The personnel on the lower floor inform the construction personnel on this floor to adjust the position of the casing slightly to ensure that the upper and lower layers of casing are concentric. After the casing positioning is completed, mark the casing position on the template in time to prevent the reinforcing bar worker from moving the casing position when laying the reinforcing bar, and weld the casing to the beam reinforcement as a whole with 8mm reinforcing bar. After the construction operator completes the casing fixing, the constructor shall report to the professional supervisor for the accuracy review and acceptance of the casing reservation, and seal the casing nozzle with yellow tape after the acceptance is passed. 
Supervise and review the acceptance of the casing.
The concrete pouring of the pipe well is carried out, and the casing is embedded and formed at one time. Continue to use this mold to reserve the casing when the casing is reserved for subsequent standard layer pipe wells. Comparative analysis of benefits
Compared with the traditional casing reservation construction method, this project not only avoids the plugging of the hanging hole in the later stage, improves the construction quality, but also has significant economic benefits, saves 56,725 yuan through comparative analysis, and realizes cost reduction and efficiency increase. 
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