Does the ground of cold storage need to be slit?

　　The key function of cold storage ground slotting is to deal with the temperature stress. When cold storage is running, the internal temperature is usually maintained at a low level, and the high temperature storage is generally above 0℃, and the low temperature storage can reach below -18℃ or even lower. In such a low temperature environment, the ground concrete will shrink due to thermal expansion and cold contraction. When this stress accumulates to a certain extent, if there are no corresponding structural measures on the ground, it will lead to irregular cracks in concrete. Setting the slit can divide the ground into relatively independent plates, forming a telescopic space between the plates. When the temperature changes, the shrinkage and expansion of concrete can be released at the slit to avoid large-scale cracking of the ground due to stress concentration. For example, in a large-scale low-temperature cold storage, the temperature in the storage is maintained at -25℃ all the year round, and the ground is provided with slits with reasonable spacing according to the specifications. After years of operation, the ground is in good condition, and only the slits show signs of normal expansion and contraction, but no other cracks are generated.

　　The scale parameters such as the length, width and height of the cold storage are the important basis for deciding whether to set the slit. Generally speaking, when the length of cold storage exceeds a certain value, the cumulative effect of temperature stress and frost heaving force over a long distance is significant, and setting slit at this time can effectively prevent ground cracking and other problems. In addition, the structural forms of cold storage, such as assembled structure and cast-in-place structure, have different requirements for slit. The connection between the components of the assembled cold storage is relatively weak, and it is more prone to deformation under the action of temperature and frost heaving. Reasonable setting of slit is helpful to coordinate the deformation of the components and ensure the integrity of the ground. Although the cast-in-place structure has good integrity, it is also necessary to cut joints to control the shrinkage and deformation of concrete in large-scale construction. ​

　　The geographical environment in which the cold storage is located is also a factor that affects whether the cold storage needs to be slit. The climatic conditions and geological conditions in the area where the cold storage is located have a great influence on the setting of ground slit. In cold areas, the winter is long and the temperature is low, and the soil frost heaving is serious. Therefore, the ground of cold storage must be provided with slits, and the spacing, depth and width of slits should be reasonably determined according to the local frozen soil thickness, extreme low temperature and other factors to enhance the frost heaving resistance of the ground. From the geological conditions, if the cold storage is built in an area with soft soil and high groundwater level, the compressibility and water content of the soil change greatly, and the ground is more susceptible to frost heaving and uneven settlement. In this case, setting slit is a necessary preventive measure; However, in areas with stable geological conditions and warm climate, if the cold storage is small, there is no need to set slits on the ground, and other measures can be taken to ensure the stability of the ground. ​