Foundation pit characteristics

1) The foundation pit supporting system is a temporary structure with small safety reserves and greater risks. During the construction of the foundation pit, monitoring should be carried out and emergency measures should be taken. Once a dangerous situation occurs during the construction process, timely rescue is required. When excavating deep foundation pits, pay attention to strengthening drainage and irrigation prevention measures. If the risk is greater, emergency plans should be prepared in advance.
2) Foundation pit engineering has strong regional characteristics. For example, soft clay foundation, loess foundation and other foundations with different engineering geological and hydrogeological conditions are very different in foundation pit engineering. There are also differences in different areas of the same city. The design and construction of the supporting system of the foundation pit engineering and the earth excavation must be adapted to local conditions and carried out according to local conditions. Experiences from other places can be used for reference, but they cannot be simply used.
3) Foundation pit engineering has a strong personality. The design and construction of the supporting system of the foundation pit engineering and the earthwork excavation are not only related to the engineering geology and hydrogeological conditions, but also related to the location of the adjacent buildings (structures) and the underground pipelines, the ability to resist deformation, and the importance, and The surrounding site conditions are related. Sometimes protecting the safety of adjacent buildings (structures) and municipal facilities is the key to the design and construction of foundation pit engineering. This determines that the foundation pit project has a strong personality. Therefore, it is more difficult to classify foundation pit projects and specify uniform standards for allowable deformation of supporting structures.
4) The foundation pit engineering is highly comprehensive. Foundation pit engineering not only requires knowledge of geotechnical engineering, but also knowledge of structural engineering. It requires the integration of soil mechanics theory, testing technology, calculation technology, construction machinery and construction technology.
5) Foundation pit engineering has strong time and space effects. The depth and plane shape of the foundation pit have a great influence on the stability and deformation of the foundation pit support system. Attention should be paid to the spatial effect of foundation pit engineering in the design of foundation pit supporting system. Soil, especially soft clay, has strong creep properties, and the earth pressure acting on the supporting structure changes with time. Creep will reduce the strength of the soil and the stability of the soil slope. Therefore, the time effect of foundation pit engineering must also be given full attention.
6) Foundation pit engineering is systematic engineering. The foundation pit project mainly includes two parts: support system design and earth excavation. Whether the construction organization of earth excavation is reasonable will play an important role in the success of the support system. Unreasonable earth excavation, steps and speed may cause the displacement of the pile foundation of the main structure, the excessive deformation of the supporting structure, and even the instability of the supporting system and lead to damage. At the same time, in the construction process, monitoring should be strengthened and strive to implement information construction.
7) Foundation pit engineering has environmental effects. Excavation of the foundation pit will inevitably cause changes in the water level and stress field of the surrounding foundations, resulting in deformation of the surrounding foundation soil, affecting surrounding buildings (structures) and underground pipelines, and seriously endangering their normal use or safety. A large amount of earthwork will also have an impact on the traffic and spoil site environment.