Novel detachable foundation pit bracing system and construction mounting method thereof

Abstract

The invention relates to the field of geotechnical engineering bracing of foundation pits, slopes, embankments and the like, and particularly discloses a novel detachable foundation pit bracing system and a construction mounting method thereof. A hydraulic jack is used for tensioning each stress application point of a steel strand, so that prestressing force of the steel strand is transmitted, and acting force is provided for the retaining structure of a foundation pit. After penetrating through a middle load transmission component, the steel strand is locked through locking devices on a cross beam. In order to monitor the prestressing force applied by the steel strand in real time and to keep stress balance between all parts, force sensors are arranged at the two ends of the steel strand and the middle load transmission component. The steel strand passes through a preformed hole in the load transmission component, the degree of tightness of the steel strand can be adjusted through a controller on the load transmission component, and the controller can move along a groove. According to the novel detachable foundation pit bracing system and the construction mounting method thereof, by adjusting the magnitude of pre-applied force of the prestressed steel strand continuously, certain supporting force and reverse acting force can be provided for a supporting structure on the side wall of the foundation pit, and the purpose of controlling deformation of the foundation pit side wall can be achieved.

Description

technical field [0001] The invention relates to the field of geotechnical engineering support for foundation pits, side slopes, embankments, etc., in particular to a novel detachable foundation pit support system and a construction and installation method thereof. Background technique [0002] At present, for foundation pit excavation, the forms of support structures are mainly divided into two categories: internal support structures and anchor structures. [0003] The internal support structure is inside the excavation of the foundation pit, and one or more steel pipes or concrete support structures are erected between the walls of the foundation pit on both sides to prevent excessive deformation or collapse of the foundation pit. When the excavation area of ​​the foundation pit is large, columns are often erected in the middle of the support structure to prevent instability and damage due to excessive slenderness of the support structure. However, this support method ofte...

AI Technical Summary

Problems solved by technology

However, the anchoring technology also has certain shortcomings. The anchor rod has a certain embedded depth, so it cannot be used when the surrounding space of the foundation pit is relatively narrow; moreover, when the construction of adjacent structures is disturbed, the anchor rod is prone to damage, reducing its Support effect; when the anchoring technology is applied in the soft soil layer, due to the small limit friction between the anchor rod body and the soft soil layer, in order to obtain greater anchoring force, the length of the anchor rod has to be lengthened, which will eventually lead to an increase in cost

[0005] Some domestic technologies mention the "fish-belly beam structure". This structure applies prestress to the purlin structure of the foundation pit, thereby providing constraints on the retaining structure. However, the steel strand loading method of this structure will cause the jack to exert a very large force. The pulling force will bring certain difficulties to the construction, and there will be a greater safety risk

Due to the location of the tension, the actual stress on the steel strands in the structure is not clear, and it is not possible to determine whether the prestress is relaxed during construction

In addition, the structure is inconvenient in the later stage of tensioning and prestressing, and the construction of supplementary tensioning will not be completed after the leaking steel bars are corroded

Moreover, there will be stress concentration in the local part of the structure, which will easily cause stress corrosion

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