In general, the plane support system should be composed of waist beam, horizontal support and column, and the horizontal support should have strong integrity and plane stiffness, so that the force transmission of each part of the support is reliable and uniform.
The function of the waist beam is to strengthen the integrity of the supporting pile and transfer the horizontal force on the supporting pile to the supporting members. Therefore, the waist beam is required to have greater plane stiffness and be reliably connected with the supporting piles.
The role of the column is to ensure the longitudinal stability of the horizontal support and bear the self-weight of the horizontal support and other vertical loads. Good rigidity and small vertical displacement are required.
According to the specific conditions of this project, horizontal bracing can be a plane structural system composed of bracing, diagonal bracing and splayed bracing.
2. Layout of plane support system
The number of horizontal supporting ways in the vertical plane of foundation pit should be determined by calculation according to the depth of foundation pit and the construction requirements of earthwork excavation.
The upper and lower horizontal support shafts should be arranged on the same vertical plane. The clear distance between vertically adjacent horizontal supports should not be less than 3m and not less than? 4m； The horizontal support elevation set on each floor shall not interfere with the construction of the underground structure layer and floor members of the main project.
In general, the horizontal capping beam at the top of the supporting pile should be used as the first horizontal supporting waist beam.