What problems should be paid attention to when the photovoltaic project enters the severe winter mode
Can earthwork be constructed in winter? It can be, but is not suitable, if it must be used in winter construction, its construction method should be determined after technical and economic comparison. Plan carefully before construction and prepare for continuous construction. The key to the construction of earthwork in winter is backfilling.
Excavation of earthwork
When excavating the earthwork by the freezing prevention method, the surface soil may be covered or ploughed before the freezing, and the depth of the ploughing shall be determined according to the local climatic conditions, generally not less than 30 cm.
Winter construction backfilling instructions
1. The thickness of the soil in each layer of the winter fill should be reduced by 20% to 25% compared with the normal temperature. The reserved settlement should be increased as compared with the normal temperature.
2. Winter fills should meet the following requirements:
(1) Ice and snow and insulation materials on the substrate should be removed before filling;
(2) Within 1m of the surface of the fill slope, it shall not be filled with frozen soil;
(3) The frozen soil blocks in the packing should be evenly distributed and laminated, and the content should meet the design requirements.
3. Filling under the ground floor, the filler shall not contain frozen clods. Anti-freezing measures shall be taken before the completion of filling to the ground.
Concrete structure engineering
1. How is the compressive strength of concrete in winter?
(1) Concrete prepared from Portland cement or ordinary Portland cement is 30% of the standard value of concrete strength designed.
(2) The concrete prepared by slag Portland cement shall be 40% of the designed concrete strength value, but not more than C10 concrete, not less than 5.0N/m2.
2. How to configure concrete for winter construction?
(1) For the preparation of concrete for winter construction, Portland cement or ordinary Portland cement should be preferred.
(2) The cement strength grade should not be lower than 32.5, the minimum cement dosage should not be less than 300kg/m3, and the water-cement ratio should not be greater than 0.6.
(3) High alumina cement is strictly forbidden for concrete mixed with antifreeze.
(4) The aggregate used for concrete must be clean and free of frozen materials such as ice and snow and minerals that are easily cracked.
(5) In the concrete containing antifreeze containing potassium and sodium ions, active aggregates shall not be mixed.