Supporting system enclosure structure in deep and large foundation pit

Abstract

The utility model provides a support system enclosure structure in a deep and large foundation pit, which relates to the technical field of foundation pit engineering construction and structurally comprises a foundation pit enclosure structure, a waterproof curtain is arranged on the outer side of the foundation pit enclosure structure, and a single-layer plane bar system support system and a vertical steel diagonal bracing system are arranged on the inner side of the foundation pit enclosure structure; the single-layer plane bar system supporting system is located at the top in the foundation pit. The vertical steel inclined strut system is located on the lower portion of the single-layer plane rod system supporting system and arranged along the periphery of the inner side of the foundation pit support structure. The waterproof curtain comprises a cement soil mixing pile and a high-pressure jet grouting pile, and the pile height of the cement soil mixing pile and the pile height of the high-pressure jet grouting pile are both higher than the underground water level line. A layer of reinforced concrete plane support is arranged on the top of the foundation pit, and a circle of vertical steel inclined struts are arranged on the periphery of the bottom of the foundation pit, so that the operation space for excavation and transportation of earthwork under the support is expanded to the maximum extent, the work amount of supporting components is reduced, the construction efficiency is effectively improved, and the investment is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation pit engineering construction, in particular to a supporting system enclosure structure in a deep and large foundation pit. Background Art

[0002] The foundation pits of high-rise buildings in modern metropolitan areas are characterized by their depth and size. These pits are often adjacent to complex environmental factors such as buildings, roads, underground facilities, and municipal pipelines. Construction conditions are becoming increasingly complex, placing high demands on environmental safety. In deep, large first- and second-level foundation pits, underground diaphragm walls and pile rows are often used as support structures. In areas with less environmental impact and favorable geological conditions, anchor rods, soil nail walls, and steel-cement-soil mixing walls can be used as support structures. These support structures typically include concrete supports, steel supports, anchor-type supports, and diagonal bracing.

[0003] In large foundation pit projects, whether using underground diaphragm walls or pile support, they need to be combined with a support system in special environments where anchor cables cannot be installed and settlement and deformation control are highly demanding. Generally speaking, orthogonal or oblique planar bar systems are sometimes required for large or irregularly shaped foundation pits. For circular, square, and nearly circular polygonal foundation pits, circular bar systems or ring plate systems can be used to create a larger excavation space. Vertical diagonal bracing can be used for shallower, larger foundation pits.

[0004] Excavation of deep and large foundation pits is often limited by planar rod supports, resulting in a construction operating space of typically only 3-5 meters, making it impossible to use large-scale mechanical equipment for excavation operations. This results in extremely low construction efficiency and often fails to meet established construction deadlines. In contrast, shallower and larger foundation pits often use vertical diagonal bracing. Therefore, in urban deep and large foundation pit construction, to meet the needs of expanding earthwork excavation space within multi-layer planar rod supports, improving construction efficiency, and ensuring safer construction, a novel internal support system enclosure structure for deep and large foundation pits was developed, combining single-layer planar rod supports with vertical steel diagonal bracing. Utility Model Content

[0005] The purpose of this utility model is to design an internal support system enclosure structure composed of a single-layer horizontal internal support system and a vertical steel diagonal support system, aiming at the defects of large construction volume and small earth excavation space in the first and second level deep foundation pit support projects with complex surrounding environments and foundation pit depths less than 15m in urban construction, and the earth excavation process. The invention can reduce the construction volume of horizontal internal support and expand the earth excavation operation space, improve construction efficiency, reduce investment, save construction period, and overcome the shortcomings of the existing technology.

[0006] The present invention provides the following technical solutions to achieve the above objectives:

[0007] A support system enclosure structure for a deep and large foundation pit, comprising a foundation pit enclosure structure, a water-stop curtain being provided on the outer side of the foundation pit enclosure structure, and a single-layer plane rod support system and a vertical steel diagonal bracing system being provided on the inner side of the foundation pit enclosure structure; the single-layer plane rod support system is located at the top of the foundation pit; the vertical steel diagonal bracing system is located at the lower part of the single-layer plane rod support system and is arranged around the inner side of the foundation pit enclosure structure; the water-stop curtain comprises cement-soil mixing piles and high-pressure rotary jet grouting piles, and the pile heights of the cement-soil mixing piles and the high-pressure rotary jet grouting piles are both set above the groundwater level.

[0008] In the aforementioned deep and large foundation pit support system enclosure structure, the single-layer plane rod support adopts a reinforced concrete structure, including a crown beam connected to the foundation pit enclosure structure as a whole, and the crown beam is connected to the reinforced concrete horizontal internal support, and the reinforced concrete horizontal internal support is connected to the steel column. The lower foundation of the steel column is a cast-in-place pile, and the top of the cast-in-place pile is the main basement floor. Multiple layers of main structure plates are arranged on the steel column, and the main structure plates are connected to the foundation pit enclosure structure through replacement support parts.

[0009] In the aforementioned deep and large foundation pit support system enclosure structure, the vertical steel diagonal bracing system is made of steel pipe material, including steel diagonal braces. The top of the steel diagonal brace is located in the steel diagonal brace corbel pier. The steel diagonal brace corbel pier forms a whole with the foundation pit enclosure structure through the waist beam. The bottom foundation of the steel diagonal brace is the steel diagonal brace corbel pier foundation, and the steel diagonal brace corbel pier foundation is located below the bottom plate of the main basement.

[0010] In the aforementioned deep and large foundation pit support system enclosure structure, the foundation pit enclosure structure includes a foundation pit retaining structure.

[0011] In the aforementioned deep and large foundation pit support system retaining structure, a drainage ditch is provided at the junction of the main basement floor and the foundation pit retaining structure.

[0012] In the aforementioned deep foundation pit support system enclosure structure, the tops of the crown beam and the reinforced concrete horizontal inner supports are set flush with the original ground.

[0013] In the aforementioned deep foundation pit support system enclosure structure, the original ground is provided with a water ditches

[0014] In the aforementioned deep foundation pit support system enclosure structure, a guardrail is provided next to the intercepting ditch.

[0015] Compared with the existing technology, the utility model uses a layer of reinforced concrete flat support on the top of the pit and a circle of vertical steel diagonal braces around the bottom of the foundation pit, which maximizes the operating space for excavation and transportation of earth and stone under the support, reduces the amount of support component engineering, effectively improves construction efficiency, and saves investment. Specifically, the utility model has the following advantages:

[0016] ① The utility model utilizes the high compressive strength of reinforced concrete to set a layer of reinforced concrete plane support on the top of the pit, which effectively resists the lateral pressure of the soil outside the foundation pit and ensures the safety of the foundation pit.

[0017] ② The utility model sets a circle of vertical steel diagonal braces around the bottom of the pit, and uses the supporting force of the vertical steel diagonal braces to replace the horizontal plane support to resist the soil pressure on the side walls of the foundation pit, thereby expanding the construction operation space within the brace and effectively improving the efficiency of earth excavation, transportation and main construction.

[0018] ③ The utility model utilizes a combination of reinforced concrete horizontal plane supports and vertical steel diagonal braces to effectively solve the problem of reducing horizontal plane support components and reducing the construction workload of plane support components under special environmental factors such as subway tunnels. The steel diagonal braces can be recycled after removal, effectively reducing construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below only relate to some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0020] Figure 1 It is a structural diagram of the utility model;

[0021] Figure numerals: 1-reinforced concrete horizontal internal support, 2-steel diagonal support, 3-foundation pit retaining structure, 4-steel column, 5-cast-in-place pile, 6-steel diagonal support corbel pier foundation, 7-steel diagonal support corbel pier, 8-waist beam, 9-basement exterior wall, 10-replacement support, 11-high-pressure rotary jet pile, 12-cement soil mixing pile, 13-main structure plate, 14-main basement floor, 15-crown beam, 16-intercepting ditch, 17-guardrail, 18-groundwater level line, 19-drainage ditch. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0023] It should be noted that in the present invention, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to the process, method, product, or apparatus. The terms "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or location relationships based on the positions or location relationships shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments, and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed and operated in a specific orientation. The terms "installed," "disposed," "provided with," "connected," "connected," and "sleeved" should be understood broadly, for example, and may refer to fixed connections, detachable connections, or integral structures; mechanical connections, or electrical connections; direct connections, indirect connections through an intermediate medium, or internal communication between two devices, elements, or components. Furthermore, some terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to express a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0024] Example. A support system enclosure structure in a deep foundation pit, the structure of which is as follows: Figure 1 As shown, it includes a foundation pit retaining structure 3, the outer side of the foundation pit retaining structure 3 is provided with a water-stop curtain, and is higher than the groundwater level line, and the inner side of the foundation pit retaining structure 3 is provided with a single-layer plane rod support system and a vertical steel diagonal bracing system; the single-layer plane rod support system is located at the top of the foundation pit; the vertical steel diagonal bracing system is located at the lower part of the single-layer plane rod support system, and is arranged along the inner side of the foundation pit retaining structure 3; the water-stop curtain includes cement-soil mixing piles 12 and high-pressure rotary jet piles 11, and the pile heights of the cement-soil mixing piles 12 and the high-pressure rotary jet piles 11 are both set higher than the groundwater level line.

[0025] The single-layer planar rod support adopts a reinforced concrete structure, including a crown beam 15 integrally connected to the foundation pit retaining structure 3. A reinforced concrete horizontal internal brace 1 is connected to the crown beam 15, which is connected to a steel column 4. The lower foundation of the steel column 4 is a cast-in-place pile 5, and the top of the cast-in-place pile 5 is the main basement floor 14. A multi-layer main structural plate 13 is installed on the steel column 4, and the main structural plate 13 is connected to the foundation pit retaining structure 3 via a replacement brace 10. The top elevation of the cast-in-place pile 5 is lower than the raft foundation.

[0026] The vertical steel bracing system is made of steel pipe material, including a steel brace 2. The top of the steel brace 2 is arranged in a steel brace corbel pier 7. The steel brace corbel pier 7 forms a whole with the foundation pit retaining structure 3 through a waist beam 8. The bottom foundation of the steel brace 2 is a steel brace corbel pier foundation 6. The steel brace corbel pier foundation 6 is arranged below the main basement floor 14.

[0027] The foundation pit retaining structure 3 includes a foundation pit retaining structure.

[0028] A drainage ditch 19 is provided at the junction of the main basement floor 14 and the foundation pit retaining structure 3 .

[0029] The top of the crown beam 15 and the reinforced concrete horizontal inner support 1 are set flush with the original ground.

[0030] The original ground is provided with a water intercepting ditch 16

[0031] A guardrail 17 is provided beside the intercepting ditch 16 .

[0032] When this embodiment is carried out, the water-stop curtain cement-soil mixing piles 12 and the foundation pit retaining structure 3 are first constructed according to the design documents, and then the high-pressure rotary jet piles 11 are constructed at the gaps of the foundation pit retaining structure 3. While the foundation pit retaining structure 3 is being constructed, the construction of the steel columns 4 and the lattice column foundation cast-in-place piles 5 is completed. Start excavating the first layer of horizontal plane supporting earthwork of the pit layer, and construct the first layer of reinforced concrete horizontal inner support 1 and crown beam 15 according to the design documents. Excavate downward from the outside of the support layer according to the earthwork excavation plan. During the process of advancing the earthwork excavation into the support, after the earthwork excavation at the position of the first steel diagonal bracing corbel pier 7 and waist beam 8 is completed, start construction of the steel diagonal bracing corbel pier 7 and waist beam 8. After the earthwork excavation at the position of the first steel diagonal bracing corbel pier foundation 6 is completed, start construction of the steel diagonal bracing corbel pier foundation 6, and then install the first steel diagonal brace 2. After the construction of the steel diagonal brace 2 is completed, continue excavating the remaining earthwork under the support. At this point, the construction of the steel-concrete composite internal support system and retaining structure of the deep foundation pit has been completed.

[0033] After excavation of the foundation pit is complete, the main basement floor slab 14 and floor slab replacement bracing 10 are completed according to the design documents. Then, gradually moving upwards, the main structural slab 13, basement exterior wall 9, and structural slab replacement bracing 10 are completed. Once the strength of replacement bracing 10 reaches the design requirements, the steel diagonal bracing 2, steel diagonal bracing corbel piers 7, and waist beam 8 are removed. Construction continues upwards, ultimately completing the removal of the first layer of reinforced concrete horizontal internal bracing 1, thus completing the deep foundation pit construction.

[0034] Among them, the reinforced concrete horizontal internal support 1 can be of beam type, plate type or steel structure type according to the size, depth and surrounding environmental factors of the foundation pit; the steel diagonal brace 2 can be of reinforced concrete structure according to actual conditions; the steel diagonal brace corbel pier foundation 6 can be of anti-slip piles as the pier foundation according to actual geological conditions when there is no bedrock.

[0035] The support system enclosure structure of the deep foundation pit implemented above utilizes a combination of reinforced concrete plane rod system and steel diagonal brace 2 system to form a steel-concrete composite support system of the deep foundation pit enclosure structure 3, and the corresponding structures are reasonably arranged, which effectively expands the operating space for excavation and transportation of earth and stone in the deep foundation pit, reduces the engineering volume of supporting components, and solves the problem that the use of multi-layer horizontal supports in deep foundation pits is inconvenient for earth and stone excavation and transportation construction.

[0036] Obviously, the above description is only a partial embodiment of the present invention, and not all embodiments. The above embodiments are not intended to limit the present invention. For those skilled in the art, various modifications and variations of the present invention are possible. Any combination, modification, equivalent replacement, improvement, and other embodiments that can be made by those of ordinary skill in the art within the spirit and principles of the present invention shall be within the scope of protection of the present invention.

Claims

1. A supporting system enclosure structure in a deep foundation pit, characterized by: The invention comprises a foundation pit retaining structure (3), wherein a water-stop curtain is provided on the outer side of the foundation pit retaining structure (3), and a single-layer plane rod support system and a vertical steel diagonal bracing system are provided on the inner side of the foundation pit retaining structure (3); the single-layer plane rod support system is located at the top of the foundation pit; the vertical steel diagonal bracing system is located at the lower part of the single-layer plane rod support system and is arranged along the inner side of the foundation pit retaining structure (3); the water-stop curtain comprises cement-soil mixing piles (12) and high-pressure rotary jet piles (11), and the pile heights of the cement-soil mixing piles (12) and the high-pressure rotary jet piles (11) are both arranged above the groundwater level; The single-layer plane rod support system adopts a reinforced concrete structure, including a crown beam (15) connected to the foundation pit retaining structure (3) as a whole, the crown beam (15) is connected to the reinforced concrete horizontal inner support (1), the reinforced concrete horizontal inner support (1) is connected to the steel column (4), the lower foundation of the steel column (4) is a cast-in-place pile (5), the top of the cast-in-place pile (5) is the main basement floor (14), and multiple layers of main structure plates (13) are provided on the steel column (4), and the main structure plates (13) are connected to the foundation pit retaining structure (3) through the replacement support member (10); The vertical steel bracing system is made of steel pipe and includes a steel brace (2). The top of the steel brace (2) is arranged in a steel brace bracket pier (7). The steel brace bracket pier (7) is integrally connected to the foundation pit retaining structure (3) through a waist beam (8). The bottom foundation of the steel brace (2) is a steel brace bracket pier foundation (6). The steel brace bracket pier foundation (6) is arranged below the main basement floor (14).

2. The supporting system enclosure structure for a deep foundation pit according to claim 1 is characterized in that: The foundation pit retaining structure (3) comprises a foundation pit retaining structure.

3. The supporting system enclosure structure for a deep foundation pit according to claim 1 is characterized in that: A drainage ditch (19) is provided at the junction of the main basement floor (14) and the foundation pit retaining structure (3).

4. The supporting system enclosure structure for a deep foundation pit according to claim 1 is characterized in that: The tops of the crown beam (15) and the reinforced concrete horizontal inner support (1) are arranged flush with the original ground.

5. The supporting system enclosure structure for deep foundation pit according to claim 4 is characterized in that: A drainage ditch (16) is provided on the original ground.

6. The supporting system enclosure structure for a deep foundation pit according to claim 5 is characterized in that: A guardrail (17) is provided beside the intercepting ditch (16).

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