Central island excavation is a kind of excavation method suitable for large-scale foundation pit. With the center as the fulcrum, excavation is carried out around, and the supporting structure is set up with the center island as the fulcrum.
Central island (pier) excavation is suitable for large-scale foundation pit, and the supporting form of supporting structure is angle brace, ring beam or side truss, leaving a large space in the middle. At this time, the pier in the middle can be used as a fulcrum to build a trestle. Excavators can use the trestle to dig in the foundation pit, and trucks carrying soil can also use the trestle to enter the foundation pit to carry soil.
Advantages: it can speed up the speed of digging and transporting soil.
Disadvantages: Because the soil around the foundation pit is excavated first, the supporting structure bears the load for a long time, and the time effect is obvious in soft clay, which may increase the deformation of the supporting structure and be unfavorable to the supporting structure.
Extended data:
When the foundation pit is deep, the groundwater level is high, and most of the excavated soil is below the groundwater level, reasonable artificial precipitation measures should be taken. In the process of precipitation, we should always pay attention to observe whether there is settlement and deformation of existing buildings or structures, roads and pipelines nearby.
During excavation, the plane control piles, leveling points, the plane position of foundation pit and the horizontal elevation slope should be checked frequently.
Earthwork excavation is a key process in the initial stage of the project and even in the construction process. Loosening, crushing, excavation and transportation projects of soil and rock. According to the geotechnical properties, earthwork excavation is divided into earthwork excavation and stone excavation.
According to whether the construction environment is open-air, underground or underwater, earthwork excavation can be divided into open excavation, hole excavation and underwater excavation. In water conservancy projects, earthwork excavation is widely used in site leveling and slope cutting, and foundation excavation of hydraulic structures (sluice, dam, spillway, hydropower plant, pumping station building, etc.). ), underground cavern excavation (hydraulic tunnel, underground powerhouse, various flat tunnels, shafts and inclined shafts), river course, channel excavation and dredging, packing, building stone, concrete aggregate mining, cofferdam or temporary buildings such as masonry and concrete.
References:
Baidu Encyclopedia: Central Island Digging