A foundation pit supporting structure by first tunneling and then welling

Abstract

The utility model discloses a kind of first tunnel after well method foundation pit supporting structures, including underground continuous wall, the underground continuous wall is set in first tunnel after well method tunnel area upper foundation pit and tunnel area foundation pit junction, concrete crown beam is provided on the underground continuous wall, a mortar anchor rod is provided inside the concrete crown beam. The present application is mainly applied to the supporting structure between deep and shallow foundation pits, which can ensure the safety of foundation pit excavation, improve construction efficiency and reduce construction cost.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering technology, specifically a support structure between deep and shallow foundation pits. Background Technology

[0002] Currently, the most commonly used support methods for foundation pits in the "tunnel-before-shaft" method are retaining piles, internal bracing, and diaphragm walls. Retaining piles are mainly constructed by drilling and grouting piles to create a barrier around the foundation pit, which helps stabilize the pit during excavation. They are primarily used in strata with low groundwater levels. In strata with high groundwater levels, they need to be combined with high-pressure jet grouting piles to form a water-stopping curtain. However, the overall rigidity of the support is relatively low. Internal bracing uses steel or reinforced concrete supports. Its advantages include good support effect and minimal foundation pit deformation. However, its disadvantages include restricting the excavation of the tunnel area and the removal of tunnel segments, limiting working conditions and reducing construction efficiency. Furthermore, the timely implementation of internal bracing or replacement bracing can be delayed due to foundation pit excavation and segment removal, creating safety risks. Diaphragm wall support has high overall structural rigidity and strength, can withstand significant soil and water pressure, and can effectively control the deformation of surrounding structures and soil settlement. However, it is more expensive and has a greater impact on the surrounding environment. Utility Model Content

[0003] To address the aforementioned issues, this invention provides a tunnel-then-shaft foundation pit support structure, primarily applicable to support structures between deep and shallow foundation pits. This structure ensures the safety of foundation pit excavation while improving construction efficiency and reducing construction costs.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows: a foundation pit support structure for the tunnel-before-shaft method, including a diaphragm wall. The diaphragm wall is set at the junction of the upper foundation pit of the tunnel area and the tunnel area foundation pit in the tunnel-before-shaft method. A concrete capping beam is set on the diaphragm wall, and a mortar anchor rod is set inside the concrete capping beam. This solution can control the excavation deformation of the foundation pit and ensure construction safety through the external anchor support system of the diaphragm wall and mortar anchor rod. At the same time, it eliminates the need to set up internal supports in the tunnel area foundation pit, avoiding the impact of internal supports in the tunnel area foundation pit on foundation pit excavation and segment breaking, and also avoiding the safety risks caused by untimely construction and replacement of internal supports; and it reduces the cost of setting up a full-width diaphragm wall at the junction of the upper foundation pit of the tunnel area and the tunnel area foundation pit in the tunnel-before-shaft method.

[0005] Furthermore, it also includes concrete supports and steel supports, which are installed inside the upper foundation pit of the tunnel area in the tunnel-first-then-shaft method.

[0006] Furthermore, the height of the diaphragm wall is half the height of the stratum at the junction of the upper foundation pit and the tunnel area foundation pit in the tunnel-first-then-shaft method. Only half of the diaphragm wall is constructed, eliminating the need for a full-width diaphragm wall. This ensures the safety of the foundation pit while saving construction costs.

[0007] The beneficial effects of this utility model are as follows: This solution, by setting up a combined structure of diaphragm wall and mortar anchor bolts at the junction of the tunnel excavation pit and forming a support system with the diaphragm wall around the perimeter of the pit, ensures the safety of the tunnel excavation. It reduces the construction risks associated with untimely internal support and support replacement, and does not affect subsequent pit excavation and segment removal operations, thus improving the efficiency of pit excavation. Furthermore, it eliminates the need for a full-width diaphragm wall at the junction of the tunnel excavation pit, significantly reducing construction costs while ensuring pit safety. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0009] The present invention will be further described below with reference to the accompanying drawings.

[0010] A type of foundation pit support structure using the tunnel-then-shaft method, such as Figure 1 As shown, the structure includes a diaphragm wall 3, concrete supports 7, and steel supports 8. The concrete supports 7 and steel supports 8 are installed inside the upper foundation pit of the tunnel section using the tunnel-first-then-shaft method. The diaphragm wall 3 is located at the junction of the upper foundation pit and the tunnel section foundation pit. The internal support structure composed of the diaphragm wall 3, concrete supports 7, and steel supports 8 is used to withstand external soil and water pressure and control the excavation deformation of the upper foundation pit in the tunnel section, thereby ensuring construction safety and the stability of the surrounding environment. The outer side of the diaphragm wall 3 is closely attached to the stratum 1. Segment 2 is installed inside the tunnel section foundation pit. A concrete capping beam 4 is installed on the diaphragm wall 3. A mortar anchor 5 is installed inside the concrete capping beam 4. One end of the mortar anchor 5 is connected to the concrete capping beam 4, and the other end is fixed in cement mortar 6. The height of the underground continuous wall 3 is half the height of the stratum 1 at the junction of the upper foundation pit of the tunnel area and the tunnel area foundation pit in the tunnel-first-then-shaft method. Only half of the underground continuous wall is constructed, and the full-width underground continuous wall is not required. This ensures the safety of the foundation pit and saves construction costs.

[0011] This scheme can control the excavation deformation of the foundation pit and ensure construction safety through the external anchor support system of diaphragm wall 3 and mortar anchor rod 5. At the same time, it eliminates the need to set up internal supports in the tunnel area foundation pit, avoiding the impact of internal supports in the tunnel area foundation pit on foundation pit excavation and segment breaking, and also avoiding the safety risks caused by untimely construction and replacement of internal supports. In addition, it reduces the cost of setting up full-width diaphragm walls at the junction of the upper foundation pit of the tunnel area and the tunnel area foundation pit in the "tunnel first, shaft later" method.

[0012] The above are only preferred embodiments of the present application, and cannot limit the scope of the present application, that is, any simple equivalent changes and modifications made according to the patent application scope and the present application description are still within the scope of the present application.

Claims

1. A foundation pit support structure using the tunnel-then-shaft method, characterized in that, It includes a diaphragm wall, which is set at the junction of the upper foundation pit and the tunnel foundation pit of the tunnel area in the tunnel-first-then-shaft method. A concrete capping beam is set on the diaphragm wall, and a mortar anchor is set inside the concrete capping beam.

2. The foundation pit support structure of the tunnel-then-shaft method according to claim 1, characterized in that, It also includes concrete supports and steel supports, which are installed inside the upper foundation pit of the tunnel area in the tunnel-first-then-shaft method.

3. The foundation pit support structure of the tunnel-then-shaft method according to claim 1, characterized in that, The height of the underground continuous wall is half the height of the stratum at the junction of the upper foundation pit and the tunnel area foundation pit in the tunnel-first-then-shaft method.

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