Technical points in the construction of water conservancy pumping stations?

According to the characteristics and geological conditions of different types of pumping stations, the buildings of water conservancy pumping stations are reasonably arranged to meet the requirements of irrigation and drainage, so as to achieve the purpose of safety, efficiency and economy. According to the construction characteristics of water conservancy pumping station, the technical difficulties and key points of each sub-item in the construction process are analyzed. The water conservancy pumping station includes several single λ engineering construction projects. The construction of single λ project is closely related, each process needs to overlap, and the coordination between single λ projects is heavy. The engineering quantity is large, the soil quality is extremely poor, and the safety of foundation and slope is affected by diving and confined water; The structure of pumping station is uneven in thickness, the flow passage is complex, and the structural appearance quality and crack prevention requirements are high; There are many levels of pumping station construction, and there are many overlaps between civil engineering and installation construction, so the workload of construction coordination is heavy; The amount of pile foundation works is large, there are many types of construction, there are many overlapping piles in the construction of different piles, and the workload of construction coordination is large; The control period of each single λ project is tight, so effective measures must be taken to ensure the realization of the progress goal, the goal of safe and civilized construction site and the goal of creating excellence in engineering quality. I. Earthwork Excavation and Drainage Engineering In order to save the project cost, the earthwork balance is very important in the process of earthwork excavation, and the combination of excavation and filling is adopted as far as possible. The upstream χ weir is filled with the soil excavated from the foundation pit, and the downstream χ weir is filled with the soil removed from the levee, so as to make rational use of the soil excavated from the foundation pit. Waste soil and backfill soil are stacked separately, which can be used when backfilling the pump house and the inlet and outlet sides, and the insufficient part can be backfilled with external earthwork. Earthwork filling shall be carried out after the foundation treatment, concealed works and foundation pit cleaning are qualified, and the embankment foundation that has passed the acceptance shall be filled in time. According to the different λ of the filled soil, different compaction methods are adopted to ensure that the backfilled earthwork meets the design requirements. Earthwork filling shall be leveled and compacted by bulldozer. After compaction, the dry density shall reach 15.5 kn/m3, and the degree of compaction shall not be less than 0.92. Backfill around the building shall be tamped by manpower and small machinery, and the compacted dry density shall not be less than 15.5 kn/m3, the compactness of cohesive soil shall not be less than 0.96, and the relative density of sandy soil shall not be less than 0.7. During foundation pit excavation, water interception, drainage and precipitation should be done well. The foundation pit must be kept dry, the groundwater λ should be kept below 50cm in the basement, and the soil quality is poor and the water content is high during the construction. In order to prevent the influence of groundwater buoyancy on foundation construction, light well point dewatering can be used. Therefore, what should be done in the process of earthwork excavation of foundation pit? Insist on pumping water during the day and tamp it with soil. When digging into the basement, drainage ditches and collecting wells should be set around the foundation pit. Surrounding drainage ditches and collecting wells are set at the bottom of the foundation pit. The foundation is concrete cushion, and the wall is block masonry, which should be combined with the cushion of the foundation pit floor. Ensure that the bottom water and seepage water can be discharged in an orderly manner, ensure that the groundwater λ drops to 500mm below the bottom plate, and set in the middle along the vertical and horizontal direction of the foundation pit? Ditch? The trench adopts plain concrete cushion, 120 thick brick, with little or no slurry, and filled with graded macadam and coarse sand. Slope is set at the bottom of the ditch, which flows to the collecting ditch next to the pit. The foundation with high water permeability has potential unfavorable factors for earthwork excavation and concrete construction, so it is necessary to drain the foundation pit in time. Ensure the slope stability and foundation safety of foundation pit excavation. In the construction, the confined water is generally reduced by deep excavation and open drainage of long trench and large mouth wells, and light well point dewatering measures are supplemented for buildings with poor local geology to effectively reduce groundwater λ; Reasonably follow λ's earthwork excavation sequence, adopt the excavation method of subsection and stratification, achieve the combination of excavation and filling, strictly control the excavation slope not to be steeper than 1: 3, reduce the lateral load of foundation pit, control mechanical disturbance, strengthen slope protection and deformation safety monitoring, do a good job in the implementation of slope emergency safety plans and measures, and strengthen the construction process control and site management to ensure the safety of foundation pit and slope. Second, the earthwork balance earthwork balance determines the increase or decrease of the project cost. It is very important to deal with the problem of earthwork balance to reduce the project cost. In the process of construction, according to the requirements of construction progress, excavation and filling are combined; Earthwork allocation should be carried out in accordance with the principle of nearby allocation, and suitable backfill filler should be given priority to the filling of buildings, dikes, public lines, etc. There are a lot of earthwork and a lot of construction machinery in the construction process, and mechanical construction has a great impact on the environment, so we must do a good job in environmental protection. 3. Foundation treatment of foundation construction engineering includes bored pile, precast silicon square pile, cement mixing pile, prestressed pipe pile, crawler bored pile, cement-soil replacement, etc. There are relatively many kinds. The quality control of pile foundation in soft soil under confined water and precast square pile in muddy soft soil are the key and difficult points of foundation treatment. Four, the main concrete construction of water conservancy pumping station The pumping station has large structural size, uneven structural thickness, complicated inlet and outlet channels and many structural layers, so as to ensure concrete. Reasonable setting of building elevation, outdoor? Glue formwork and high-quality release agent are used for concrete surface, and special-shaped piece λ is assembled on site by fixed processing formwork. By optimizing concrete mixture ratio, mixing concrete with cold water by multi-mixing technology, strengthening λ structure in weak parts of structure, setting keyway and temporary water stop at construction joints, and strengthening concrete thermal insulation and curing, the appearance quality of concrete is ensured, and the crack resistance and quality of concrete are improved. The main concrete construction process is as follows: 1 concrete construction of pumping station 1. 1 construction of concrete cushion pile foundation and cutoff wall, and the cutoff wall section is carried out according to the design requirements? After testing the water, it is confirmed that the anti-seepage effect meets the design requirements, and the pumping station floor construction can be carried out. The concrete pump truck will directly drive the cushion to the pouring bin surface and level it manually. When pouring, flat vibrator shall be used for vibration compaction. 1.2 The bottom plate of the station body is constructed with combined large steel formwork, and the χ diagram is made of double rows of small steel pipes. When reinforcing the splayed vertical formwork with steel pipes, pay attention to protect the horizontal water stop, vertical water stop and expansion joints. The bottom bin of the pumping station has a large area, and the height difference of λ layer on the inlet side, the outlet empty box side and the manhole empty box is large. Using subsection and horizontal layering method, from low to high construction, the corridor layer is completed first, and then the water inlet layer is constructed. The retarder used in the construction of bottom silicon is determined by experiments to prevent cold joint. After the bottom plate is poured, the settlement observation nails are arranged on the top surface according to the design drawings to observe the settlement value and buildings. Increase the observation level of load settlement once until it moves to the top surface. 2 Inlet channel and empty box construction Inlet channel layer and empty box construction interface: empty box roof on the upper side of the station-empty box roof on the corridor-top surface of inlet channel, including side piers, partition piers, elbow inlet channel, pump piers and empty box roof. The construction process is as follows: layer treatment-gate embedded parts installation-formwork installation-steel bar binding-formwork fabrication, installation and reinforcement-warehouse surface acceptance-concrete pouring-maintenance. 3. The construction process flow of the pump well and the bottom plate of the outlet canal is as follows: slurry block stone core wall-layer treatment-bottom formwork and side formwork-steel bar welding and binding (including steel feet embedded in the next construction)-formwork preparation and reinforcement-warehouse surface acceptance-pouring-maintenance. For the construction of coupling layer and outlet channel, carefully chisel the wall construction joints? Clean and recheck the λ of wall and steel dowel, then set up formwork and steel dowel, and the steel bar connection adopts single-sided arc welding. The concrete of the connecting layer beam slab is poured from one end to the other at one time. The outlet channel formwork is an integral formwork built inside and outside, and the inner and outer surfaces are horizontally layered and poured in a balanced way. The structure of outlet channel and coupling layer is complex, and steel dowel is reserved for local beam and slab inside, which is convenient for later pouring. 5. During the construction of the coupling layer and outlet channel layer of the motor building roof, the external wall of the pier wall of the station body is poured once, and the roof of the motor building is constructed by hanging method. 6 construction procurement anti-crack fiber concrete composite anti-crack fiber is pressed with concrete in the factory? The machine mixing quantity is subcontracted and packaged, and it is directly put into the hopper by special personnel when mixing on site. The mixing time shall be prolonged by 15S to 60S, and the best mixing time shall be determined through field trial mixing. Inlet and outlet canals and external canals of the pumping station project? The concrete of retaining wall is mixed with composite anti-crack fiber, so it should be poured in advance during construction to achieve multi-purpose and multi-mixing. The moisture curing time of concrete after molding is extended to 2 1 day. V. Installation of mechanical and electrical equipment and overall structure The quality of mechanical and electrical equipment installation project is directly related to the normal operation of the pumping station, and the construction process overlaps with civil engineering, which has great interference in construction. The installation quality of mechanical and electrical equipment is the internal core of engineering quality. Coordination and progress control of intransitive verb contractors There are relatively many contractors for the construction of water conservancy pumping stations, including material suppliers, equipment suppliers, civil contractors, architectural decoration contractors, multiple operation groups within contractors, engineering and local parties; The construction work is relatively concentrated, and the process sequence between structures is strict, which is not convenient for sudden work rush, but easy for slow work to produce fine work. Therefore, coordinating the relationship between all parties and arranging the construction scientifically is related to whether the project can play its role as scheduled. To sum up, the construction quality of water conservancy pumping station project is closely related to residents' life. In the process of construction, it is necessary to check the quality at different levels to achieve the best engineering quality. At the same time, attention should be paid to improving the sense of responsibility and technical quality of construction technicians to provide higher quality services for urban development.

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