Requirements and preparations for civil construction of large-scale photovoltaic grid-connected systems

Requirements and preparations for civil construction of large-scale photovoltaic grid-connected systems

The site leveling and earthwork construction of the power station shall comply with the relevant provisions of the “Code for Acceptance of Construction Quality of Building Foundation Engineering” GB50202–2002. Earthwork works mainly include site level cut and fill of the booster station of the comprehensive building, and earthwork of the roads in the site area. Before construction, the engineering geological structure, topography and hydrology should be understood in detail, and effective preventive protection measures should be taken for unfavorable geological sections. According to the scope of the construction land, the waste slag shall be piled up at the designated location.

Before the construction of each unit project, according to the construction drawings and the provisions of this technical clause, submit it to the relevant personnel for approval, mainly including: ① excavation construction plan and section layout; ② construction equipment configuration and labor arrangements; ③ measures for slag removal and slag disposal; ④ quality and safety assurance measures; ⑤ drainage measures; ⑥ construction progress plan.

(1) Requirements for earthwork excavation

All excavation operations are in accordance with the design drawings and the requirements of relevant specifications. The excavated weathered rock blocks, slope deposits and residues shall be excavated and cleaned according to the requirements of the construction drawings, and shall be completed before filling. It is forbidden to excavate and remove the waste while filling, and all the waste should be transported out of the foundation area and stacked on the designated site. Attention must be paid to the protection of underground pipes, cables, cultural relics and other structures not shown in the drawings. Once the above structures are found during the excavation, report immediately, stop the operation and protect the site for disposal. After the earthwork excavation project is completed, the following completion acceptance materials shall be submitted in accordance with the provisions of this contract: ① the completion drawing of the excavation project; ② the quality inspection report; ③ other materials required by the supervisor.

(2) Preparation of concrete works

Concrete is mainly used for support foundation and booster station. Although the total amount is large, the demand per unit time is small, and it can be mixed by small concrete mixers. In the construction of concrete structures, according to the structural characteristics, the greenhouse method or the heat storage method should be used to ensure the quality of concrete construction in different seasons.

Concrete construction includes: ① Aggregate supply, transportation and all equipment and auxiliary facilities required for test and inspection. ② Carry out all kinds of concrete mix design, concrete mixing, transportation, pouring, plastering, curing, maintenance and sampling inspection of all concrete construction operations, as well as procurement, transportation, acceptance and storage of raw materials required for pouring concrete. ③Provide the material of the formwork and the design, manufacture, installation, maintenance and dismantling of the formwork required for the project. ④Provide reinforcement of reinforced concrete structure and its production, transportation and construction. ⑤Provide procurement, supply, fabrication and installation of materials and related equipment required for concrete temperature control and surface protection.

(3) Template

Formwork construction includes: ① formwork material supply, design, production, transportation, installation and removal of all formwork operations. The design, production and installation of the formwork should ensure that the formwork structure has sufficient strength and rigidity, can withstand the lateral pressure and vibration force of concrete pouring and vibration, prevent displacement, and ensure that the external dimensions of the concrete structure are accurate. And there should be sufficient sealing to avoid slurry leakage. ②Before the formwork is processed, according to the requirements of the construction drawings, submit a formwork design and construction measures documents including the material varieties and specifications of various types of formwork in this project, the structural design of the formwork, and the production, installation and removal of the concrete pouring formwork, and submit it for approval.

The engineering formwork generally adopts steel formwork; the support material is preferably steel, reinforced concrete or concrete. The quality of the formwork material conforms to the current national standards and industry standards. The quality of the wood should reach the material standard of grade III or above, and the use of rotten, severely twisted or brittle wood is strictly prohibited. The thickness of the steel formwork panel is not less than 3mm, and the steel plate surface should be as smooth as possible, and no pits, wrinkles or other surface defects are allowed.

The production of the formwork shall meet the requirements of the construction drawings for the structural shape of the building, and the allowable deviation of its production shall not exceed the specification. Measure and stake out the formwork installation according to the construction drawings. During the installation process, set up enough temporary fixing facilities to prevent deformation and overturning.

Steel formwork should be cleaned before each use. In order to prevent rust and facilitate formwork removal, the steel formwork panel should be painted with mineral oil-based anti-rust protective paint, and no oil agent that pollutes the concrete shall be used, and shall not affect the quality of concrete or reinforced concrete. If the inspection finds that there are stains on the poured concrete surface, effective measures should be taken to remove it. The surface of the wood formwork should be affixed with galvanized iron or other partitions. When the strength of the concrete reaches that its surface and edges and corners are not damaged by the removal of the formwork, it can be removed.

(4) Rebar material

Reinforcement material construction includes: ①Procurement, transportation, acceptance and storage of reinforcing steel materials, and according to the contract, the incoming steel material inspection and inspection personnel warehouse shall be carried out. When the supervisor considers it necessary, the supervisor shall be notified to participate in the inspection and inspection work. ② Reinforcement operations include the fabrication, welding, installation and pre-embedding of rebars, rebar meshes and rebar skeletons. ③ If other types of steel bars are used to replace the steel bars specified in the construction drawings, the report on the replacement of steel bars shall be submitted for approval.

Material requirements for steel bars: ① The type, steel number, diameter, etc. of steel bars used in reinforced concrete structures conform to the provisions of relevant design documents. The properties of hot rolled steel bars must meet the requirements of current industry standards. ② Each batch of steel bars is accompanied by a product quality certificate and a factory inspection sheet. Before use, the following mechanical property tests of steel bars are carried out in batches. According to the steel bar quality certificate provided by the manufacturer, check the appearance quality of each batch of steel bars, and measure the representative diameter of each batch of steel bars. In each batch of steel bars, two steel bars that are qualified for surface inspection and dimensional measurement are selected for tensile test and cold bending test respectively. ③ The steel bars that need to be welded shall be tested for the welding process.

Processing and installation requirements of steel bars: ① The surface of steel bars should be clean and free of damage, and paint pollution and rust should be removed before use. Rebar with granular or flaky old rust shall not be used. ② The steel bars should be straight without local bending, and the straightening of the steel bars should comply with the following regulations: when the steel bars are straightened by the cold drawing method, the cold drawing rate of the I-grade steel bars should not be greater than 2%; the cold drawing rate of grade II and III steel bars should not be greater than 1%. After the steel bar is straightened on the straightening machine, the surface shall not have obvious scratches, and the tensile strength shall not be lower than the requirements of the construction drawings. ③ The size of the steel bar processing shall meet the requirements of the construction drawings, and the hook bending processing of the steel bar shall meet the requirements of the specification. ④ Welding of steel bars and binding of steel bars shall be carried out in accordance with the regulations and the requirements of construction drawings.

Related Posts