Foundation Pit Containment System and Construction Method Using Underground Diaphragm Wall as Vertical Cantilever Fulcrum

Abstract

The invention discloses a foundation pit enclosure system using an underground diaphragm wall as a vertical cantilever supporting point and a construction method. The foundation pit enclosure system comprises a basement, wherein the basement is mainly formed by correspondingly connecting basements located in the peripheral region of a foundation pit and basements located in residual regions of the foundation pit through respective floor slabs. Each basement located in the peripheral region of the foundation pit comprises the underground diaphragm wall, lateral shear resisting walls and floor slabs, the underground diaphragm wall is arranged along the circumference of the inner wall of the foundation pit and serves as the peripheral edge of the peripheral region of the foundation pit, the inner edge of the peripheral region of the foundation pit serves as a boundary for the central region of the foundation pit and the peripheral region of the foundation pit, the lateral shear resisting walls are distributed in the peripheral region of the foundation pit, and the floor slabs are arranged on the lateral shear resisting walls and the underground diaphragm wall in a layered mode. The lateral shear resisting walls serve as supporting structures at an early stage and are also the constituent parts of a main body structure, so that the problem that temporary supports are needed to be erected in construction and then are needed to be removed in the prior art is solved, construction difficulty is simplified, a construction period is shortened, and construction cost is reduced.

Description

technical field [0001] The present invention relates to basement upside-down method of multi-tower high-rise super large chassis and foundation pit support technology, in particular to a foundation pit enclosure system with underground diaphragm wall as vertical cantilever fulcrum, which can be used as super large foundation pit enclosure system. Pit containment system, also relates to the construction method of the foundation pit containment system. Background technique [0002] The foundation pit enclosure system is a general term for the retaining structure, groundwater control, and environmental protection measures required to ensure the safety and stability of the underground space formed by excavating from the ground during the construction of the underground structure. The foundation pit engineering mainly includes the design and construction of the foundation pit enclosure system and earthwork excavation. It is a highly comprehensive system engineering, which require...

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Problems solved by technology

[0005] ⑴Because the super-large deep foundation pit is very deep (usually the depth is greater than 20 meters), it is necessary to add a horizontal support system. At the same time, if the scale of the foundation pit is large, the horizontal support system needs to add temporary vertical supports (such as column piles), which will lead to There are many upright piles, and more upright piles will conflict with the main structure of the building, making construction difficult and prolonging the construction period

(2) The added vertical support and horizontal support greatly increase the project cost, and when excavating the earthwork of the foundation pit, it is difficult to excavate the foundation pit

[0007] The reverse construction method has the advantages of improving the safety of underground engineering, reducing waste of resources, shortening the total construction period, and having little impact on the surrounding environment. However, its defects are: (1) Construction is carried out from top to bottom, requiring high construction accuracy and high technical difficulty. Node processing is complex; (2) The entire foundation pit system is highly systematic, requiring close cooperation between the design department and the construction department, and construction is carried out in strict accordance with the design drawings, which increases the cooperation between the design department and the construction department; (3) Since the excavation is in the The top is closed, and there are a certain number of intermediate support columns and well point pipes for dewatering in the foundation pit, so it is difficult to excavate the soil, the construction period of the earthwork will be longer than the conventional method, and the cost of the whole project is high; (4) the support position is limited by the basement If there is a basement with a relatively high building height, due to the large area of ​​the basement, it is necessary to set up temporary horizontal supports or increase the section and reinforcement of the enclosure wall; (5) The support piles and columns used as vertical supports are temporary supports. It needs to be dismantled during the construction of the main structure, which increases the difficulty of construction and increases the construction cost

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