An internally braced basement excavation enclosure system

Abstract

The application provides an inner support basement foundation pit enclosure system, which is applied to the technical field of foundation pit enclosure and comprises a retaining structure, a temporary horizontal support structure and a permanent vertical support structure for supporting the retaining structure along the periphery of the foundation pit, the retaining structure is arranged along the inner wall of the foundation pit, the permanent vertical support structure comprises a plurality of groups of permanent lateral force resisting vertical members with a high length-width ratio continuous force section in at least a lateral direction, wherein the lower end of the member is anchored below the bottom plate of the basement, the member is constructed by using a top-down method and is reserved in a peripheral area on the inner side of the basement after construction is completed, a plurality of structural columns are also constructed in the peripheral area by using a bottom-up method, the plurality of structural columns and the plurality of groups of permanent lateral force resisting vertical members are distributed in the peripheral area in a staggered manner, and the foundation pit enclosure system has the advantages of less use of temporary members, convenient use of the main structure and the like.

Description

Technical Field

[0001] This application relates to the field of foundation pit support technology, specifically to an internally supported basement foundation pit support system. Background Technology

[0002] Existing internally supported foundation pit retaining systems generally include retaining structures, internal support structures, and anchor bolt components. The retaining structure is generally composed of vertical support members installed on the sidewalls of the foundation pit and embedded at their lower ends into the bottom of the pit. The internal support structure is divided into horizontal and vertical members. The horizontal members are generally reinforced concrete, steel, or steel-concrete composite horizontal bracing. The vertical members are generally point-column bearing piles such as column piles, cast-in-place piles, or precast piles. Anchor bolts are rods installed on the retaining structure that extend into the soil outside the foundation pit, such as steel strands, reinforcing bars, or steel pipes.

[0003] Existing internally supported foundation pit retaining systems generally employ the sequential construction method, which involves excavating downwards layer by layer in a natural sequence, followed by constructing the main structure upwards layer by layer. This method has a clear logical process and avoids the complex coordination involved in the simultaneous construction of above-ground and underground structures, as in the reverse construction method. However, the sequential construction method encounters several problems. Firstly, the retaining system typically only installs temporary lateral force resisting components, such as internal supports and diagonal braces, within the basement boundary. These temporary components affect the normal construction of the basement's main structure and need to be removed in advance, thus increasing the workload. Furthermore, the basement is not yet completed when these temporary lateral force resisting components are removed, and the foundation pit retaining system still needs to function, adding the work of replacing supports. This results in a longer design period and higher costs for the retaining system.

[0004] Some existing technologies propose using a combination of forward and reverse construction methods for basement foundation pit retaining structures. Specifically, the main basement structure is divided into two parts. One part is constructed using the reverse construction method in the perimeter area of ​​the pit, including diaphragm walls, shear walls, and floor slabs. After completion, the diaphragm walls, shear walls, and floor slabs together serve as retaining and water-blocking structures. The other part is constructed using the forward construction method in the remaining area of ​​the pit. After completion, the two main structures are connected by their respective floor slabs. While this approach can reduce the workload of dismantling and replacing temporary components, it presents the following potential problems:

[0005] I. Because the construction of the basement main structure adopts both reverse construction and forward construction, the process is complex and varied, and the junction between forward and reverse construction is difficult to handle, making it difficult to guarantee the construction quality.

[0006] Second, in reverse construction, permanent structures such as diaphragm walls and shear walls are rigidly connected to the floor slabs and bear loads during the construction phase. Their spatial layout and mechanical properties cannot meet the needs of later building use. For example, in later use, it needs to withstand large vertical loads, but the distance between shear walls is large, resulting in very high beams, which affects the building's functionality. Utility Model Content

[0007] In view of this, the embodiments of this specification provide an internally supported basement foundation pit retaining system and its construction method, which has the advantages of using fewer temporary components, convenient use of the main structure, and comfort.

[0008] This specification first provides an internally supported basement pit retaining system, including a retaining structure and temporary horizontal support structures and permanent vertical support structures that laterally support the retaining structure. The retaining structure is arranged along the inner wall of the pit. The permanent vertical support structure includes multiple sets of permanent lateral force resisting vertical members with continuous load-bearing sections having a high aspect ratio at least in the lateral direction. The lower ends of the members are anchored below the basement floor slab. The members are constructed using the reverse construction method and are retained in the perimeter area inside the basement after construction. In this perimeter area, multiple structural columns are also constructed using the forward construction method. The multiple structural columns and the multiple sets of permanent lateral force resisting vertical members are staggered in this perimeter area.

[0009] To optimize the above solution, the following technical measures were also adopted:

[0010] As one embodiment, the permanent lateral force resisting vertical member adopts a reinforced concrete structure, a steel structure, or a combination of reinforced concrete and steel structure.

[0011] In one embodiment, the permanent lateral force resisting vertical member is composed of multiple pile foundations arranged in a horizontal line; and / or the permanent lateral force resisting vertical member is formed by concrete pouring of multiple vertical bearing piles arranged in a horizontal direction; and / or the permanent lateral force resisting vertical member is formed by steel structure restraint of multiple vertical bearing piles arranged in a horizontal direction.

[0012] In one embodiment, the permanent lateral force resisting vertical members are arranged in the form of a straight wall.

[0013] As one implementation method, the permanent lateral force resisting vertical member improves its stiffness by taking prestressing measures.

[0014] As one implementation method, the permanent lateral force resisting vertical member enhances its lateral force resisting capacity by taking counterweight measures.

[0015] In one embodiment, the retaining structure includes multiple vertical support members, and the temporary horizontal support structure includes multiple temporary lateral force resisting horizontal members. The vertical support members and / or the temporary lateral force resisting horizontal members are removable and reusable members.

[0016] In one embodiment, the temporary horizontal support structure further includes a support plate connected to a temporary lateral force resisting horizontal member, the surface of which is adapted to provide a construction work site.

[0017] As one implementation method, after the basement construction is completed, the permanent lateral force resisting vertical member is located inside the basement exterior wall and is arranged perpendicular to the basement exterior wall.

[0018] 10. A construction method for the internally supported basement foundation pit retaining system as described above, specifically including the following steps:

[0019] S1. Construct the retaining structure and permanent lateral force resisting vertical components in the foundation pit according to the design drawings, and at the same time construct the pile foundation of the main structure as needed;

[0020] S2. Excavate the soil inside the foundation pit between the ground surface and the first temporary horizontal support structure;

[0021] S3. Construct the first temporary horizontal support structure and complete the connection between the first temporary horizontal support structure and the retaining structure and the permanent lateral force resisting vertical components;

[0022] S4. After the strength of the first temporary horizontal support structure reaches the required level, excavate the soil inside the foundation pit between the first temporary horizontal support structure and the second temporary horizontal support structure.

[0023] S5. Construct the second temporary horizontal support structure and complete the connection between the second temporary horizontal support structure and the retaining structure and the permanent lateral force resisting vertical members.

[0024] S6. Repeat steps S4 to S5 until the last temporary horizontal support structure is completed. Then, excavate the soil from the last temporary horizontal support structure down to the foundation pit until the earthwork excavation is completed.

[0025] S7. Construct the basement floor slab and complete the connection between the floor slab and the retaining structure and permanent lateral force resisting vertical members;

[0026] S8. The temporary support structure is dismantled in sequence while the main structure of the basement, including multiple structural columns, is constructed.

[0027] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least:

[0028] Firstly, in this utility model, to meet the performance requirements of foundation pit support, the permanent lateral force resisting vertical members are configured with a continuous load-bearing section having a high aspect ratio in the lateral direction. This significantly increases the lateral stiffness of the members, thereby enhancing the overall support capacity or soil and water retention capacity of the foundation pit retaining system. The formula for the moment of inertia of the section is 1 / 12bh. 3 For a conventional foundation pit, assuming a 1m thick diaphragm wall with a length of 18m, its moment of inertia is 1 / 12 x 18 x 1. 3 =1.5m 4 Using the technology of this invention, assuming the permanent lateral force resisting vertical member is 0.8m thick and 5m long, its moment of inertia is 1 / 12 x 0.8 x 5. 3 =8.33m 4 This means that the bending resistance of this component can reach 5.6 times that of a conventional foundation pit.

[0029] Furthermore, in this utility model, the permanent lateral force resisting vertical members are constructed using the reverse construction method and are retained in the perimeter area inside the basement after construction. The other main structures of the basement are still constructed using the forward construction method. This gives the foundation pit retaining system good performance in later use. After the earthwork excavation is completed, multiple structural columns can be constructed in the perimeter area as needed using the forward construction method. These structural columns and multiple sets of permanent lateral force resisting vertical members are arranged in an alternating manner in the perimeter area. This can reduce the distance between adjacent vertical members in the area, thereby reducing the span of the beam and lowering the height of the beam.

[0030] In addition, retaining the lateral force resisting vertical members as permanent components in the surrounding area inside the basement can be coordinated with some flexibly planned spaces such as parking spaces, with almost no impact on the building's function, and can maximize the utilization efficiency of the basement. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the construction plan in Embodiment 1 of this application;

[0033] Figure 2 This is a cross-sectional schematic diagram of Embodiment 1 of this application;

[0034] Figure 3 This is a schematic diagram of the basement building layout in Embodiment 1 of this application;

[0035] Figure 4 This is a schematic diagram of the existing basement building layout;

[0036] Figure 5 This is a schematic diagram of the basement structural layout in Embodiment 1 of this application;

[0037] Figure 6 This is a cross-sectional schematic diagram of the ballast measure taken in Embodiment 1 of this application;

[0038] Figure 7 This is a cross-sectional schematic diagram of the prestressing measures taken in Embodiment 1 of this application;

[0039] Figure 8 This is a structural schematic diagram of one form of the permanent lateral force resisting vertical member in Embodiment 1;

[0040] Figure 9 This is a structural schematic diagram of another form of the permanent lateral force resisting vertical member in Embodiment 1. Detailed Implementation

[0041] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0042] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0044] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0045] This specification presents an internally supported basement foundation pit retaining system and its construction method, as described in the embodiments. Figure 1 As shown, this invention aims to address the problems in existing internally supported foundation pit retaining systems, such as the large amount of temporary support components used during construction, leading to a large workload for dismantling or replacing supports, or the complex and varied construction procedures of the main structure. It can further reduce the amount of temporary support components used during construction while still adopting the traditional sequential construction method.

[0046] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0047] Example 1

[0048] like Figures 1 to 3 and Figure 5 As shown, the embodiments of this specification first provide an internally supported basement pit retaining system, wherein the basement includes at least one underground floor. In this embodiment, a two-story basement is used as an example to illustrate the solution. However, it should be understood that this is not a limitation on the scope of protection of this utility model. In fact, the pit retaining system of this utility model is particularly suitable for the construction of multi-story basements, such as three-story or higher basements.

[0049] Specifically, the internally supported basement pit retaining system includes a retaining structure 1 and an internal support structure supporting the retaining structure 1 along the perimeter of the pit. The retaining structure 1 is set along the inner wall of the pit. The internal support structure includes a temporary horizontal support structure and a permanent vertical support structure. The permanent vertical support structure includes multiple sets of permanent lateral force resisting vertical members 24 with continuous load-bearing sections having a high aspect ratio at least in the lateral direction. The lower ends of the members are anchored below the basement floor 43. The members are constructed using the reverse construction method. During the construction of the basement, they serve as lateral force resisting members of the pit. After the construction is completed, they are retained in the perimeter area inside the basement as part of the vertical load-bearing members of the basement. In this perimeter area, multiple structural columns 5 are also constructed using the forward construction method. The multiple structural columns 5 and the multiple sets of permanent lateral force resisting vertical members are arranged in an alternating manner in this perimeter area.

[0050] Here, apart from the lateral force resisting vertical member 24, the basement main structure is still constructed using the traditional sequential construction method, i.e., excavation followed by construction. During construction, the lateral force resisting vertical member 24 does not bear the vertical force of the above-ground tower structure. To meet the requirements of foundation pit support, this utility model sets the lateral force resisting vertical member 24 to have a continuous load-bearing section with a high aspect ratio in the lateral direction. This greatly increases the lateral stiffness of the member, thereby improving the overall support capacity or soil and water retention capacity of the foundation pit retaining system. Based on this, as... Figure 3 As shown, the lateral force resisting vertical members 24 are retained as permanent members in the perimeter area of ​​the basement. Preferably, they are retained in the basement, avoiding the perimeter area of ​​the above-ground tower structure. The lateral force resisting vertical members 24 are coordinated with some flexibly planned spaces, such as parking spaces, within this area, having almost no impact on the building's function and maximizing the basement's utilization efficiency. This reduces the amount of temporary support components used and achieves a rational and efficient arrangement and layout of the permanent-temporal combined components used in the continuous construction method within the basement's main structure.

[0051] like Figure 3 and Figure 5 As shown, here, the permanent lateral force resisting vertical members are constructed using the reverse construction method and remain in the perimeter area inside the basement after completion. The other main basement structures are still constructed using the forward construction method. This gives the foundation pit retaining system good post-construction performance. After the excavation is completed, multiple structural columns 5 can be constructed in the aforementioned perimeter area using the forward construction method as needed. These structural columns 5 and multiple sets of permanent lateral force resisting vertical members 24 are staggered in this perimeter area, which reduces the distance between adjacent vertical members in this area, thereby reducing the height of the beams 6 in the main basement structure. Furthermore, in the existing technology, because the reverse construction method is used in the perimeter area of ​​the basement, all vertical members must be completed by piling, which is difficult to construct and has low positioning accuracy. Therefore, as... Figure 3 As shown, in this embodiment, structural column 5 is constructed using the normal sequential construction method, which is easy to construct and allows for accurate positioning.

[0052] Here, "lateral" specifically refers to the direction along which lateral force is transmitted. "Continuous load-bearing section" means a section in which the stress performance of a member remains continuous and without abrupt changes in at least one direction. This "one direction" specifically refers to the lateral direction, and can also refer to the pressure direction of the surrounding soil. The "length" in the aspect ratio refers to the length of the vertical member extending in the lateral direction, and the "width" refers to the length of the vertical member extending in the horizontal direction perpendicular to the lateral direction, i.e., its thickness. A high aspect ratio, for example, means an aspect ratio at least greater than 1:1; in some cases, it can also be defined as greater than 2:1 or 3:1. Compared to point-column vertical members, the lateral force-resisting vertical member 24 in this embodiment, due to its special cross-sectional structure, can achieve higher lateral stiffness, thereby significantly improving the support capacity of the foundation pit. For example, the formula for the moment of inertia of the section is 1 / 12bh. 3 For a conventional foundation pit, assuming a 1m thick diaphragm wall with a length of 18m, its moment of inertia is 1 / 12 x 18 x 1. 3 =1.5m 4 Using the technology of this invention, assuming the permanent lateral force resisting vertical member is 0.8m thick and 5m long, its moment of inertia is 1 / 12 x 0.8 x 5. 3 =8.33m 4 This means that the bending resistance of this component can reach 5.6 times that of a conventional foundation pit.

[0053] It should be noted that since the lateral force resisting vertical member 24 is not removed after the basement is built and also serves as a vertical load-bearing member of the main structure, it needs to meet both the stress requirements of the foundation pit and the stress requirements of normal use. This vertical member is a permanent-temporary combined member, and its position and cross-section must simultaneously meet the requirements of multiple disciplines such as architecture, structure, and foundation pit.

[0054] In this embodiment, the structural forms of the lateral force resisting vertical members are diverse, including reinforced concrete structures, steel structures, or a combination of reinforced concrete and steel structures. Similarly, the temporary horizontal support structure can be a reinforced concrete structure, a steel structure, or a combination of reinforced concrete and steel structures.

[0055] In some specific implementation methods, such as Figure 8 As shown, the lateral force resisting vertical member 24 can be composed of multiple pile foundations 241 arranged in a horizontal line laterally or constrained by a steel structure by multiple vertical bearing piles arranged laterally, wherein the bearing piles are, for example, precast piles or cast-in-place piles. Furthermore, the construction methods are flexible and diverse, including precast, cast-in-place, or a combination of both.

[0056] Preferably, multiple lateral force resisting vertical members 24 are arranged around the perimeter of the foundation pit, and they can have different aspect ratios in the horizontal direction, such as... Figure 1 As shown, since the lateral force resisting vertical members 24 have higher lateral stiffness than the point column vertical members, only a small number of the above-mentioned lateral force resisting vertical members 24 are needed to replace a large number of temporary support point column vertical members to meet the support requirements of the foundation pit. The elimination of a large number of point column vertical members and the horizontal support members connected to them can save a lot of internal space of the foundation pit and bring great convenience to the construction operation.

[0057] As a preferred option, such as Figure 7 As shown, the lateral force resisting vertical member 24 improves its stiffness by adopting prestressing measures. In some embodiments, multiple prestressing ducts are pre-embedded inside the lateral force resisting vertical member 24, and steel strands 7 are inserted and tensioned to the design stress using the post-tensioning method. After being fixed by anchors, cement grout is injected to seal the structure, forming a prestressed system to increase the stiffness of the member and reduce deformation under load.

[0058] As a preferred option, such as Figure 6 As shown, the lateral force resisting vertical member 24 enhances its lateral force resisting capacity by employing counterweight measures, such as adding a counterweight to the top of the vertical member. As a practical application, the temporary horizontal support structure also includes a support plate (not shown) connected to the lateral force resisting horizontal member 23, for example, as... Figure 1 As shown, the support plate can be fixed to the prefabricated steel truss. The surface of the support plate is suitable for providing a construction work area, thus facilitating on-site construction operations. Simultaneously, the weight borne by the support plate acts as a counterweight on the lateral force-resisting vertical member 24, further increasing the lateral stiffness of the permanent lateral force-resisting vertical member 24 and thereby improving the safety of the foundation pit support. As another reasonable application, counterweights, such as any available weight on site, can be applied to the lateral force-resisting vertical member 24, without limitation. Furthermore, the support plate is a removable and reusable component.

[0059] In some embodiments, the vertical support structure may also include steel columns, steel composite columns, etc., for temporary auxiliary support.

[0060] In this embodiment, the retaining structure 1 includes a vertical support member, which mainly bears the pressure of the soil surrounding the foundation pit and serves to retain soil and water. The horizontal support structure includes a lateral force resisting horizontal member 23. The vertical support member and / or the lateral force resisting horizontal member are removable and reusable components, thereby saving construction costs. Compared with the prior art where the horizontal support member serves as both a temporary enclosure and a permanent structural floor slab, this avoids the inconvenience caused by considering the stress conditions under both working states. For example, if the support stiffness is insufficient, long-term deformation exceeding the limit after conversion into a floor slab can lead to wall cracking.

[0061] Specifically, a displacement compensation device can also be installed on the horizontal members resisting lateral forces to compensate for the displacement of the horizontal members resisting lateral forces that affects the safety of the foundation pit under the action of temperature and load.

[0062] Specifically, the retaining vertical members can be sheet piles, steel composite piles, or steel sheet piles. Furthermore, the retaining structure 1 also includes a capping beam and / or a waist beam installed on the retaining vertical members to connect them to the horizontal support structure. Compared to using non-removable components such as diaphragm walls, the construction process for these retaining vertical members is simpler and less costly. Preferably, the lateral force resisting horizontal members 23 can be steel structures, such as steel pipe support structures, steel profile support structures, or similar structures. Figure 1 The prefabricated steel truss support structure shown is an example.

[0063] As a preferred option, such as Figure 9 As shown, the lateral force resisting vertical member 24 is arranged in the shape of a straight wall 242. After the basement construction is completed, the lateral force resisting vertical member 24 is located inside the basement exterior wall 41 and perpendicular to the wall surface of the basement exterior wall 41. As a preferred embodiment, parking spaces are arranged in rows along the inner side of the basement exterior wall 41, and the lateral force resisting vertical members 24 are distributed at intervals in the area separated from at least some parking spaces by adjacent parking spaces, and the long side of the lateral force resisting vertical member 24 in the horizontal direction is parallel to the direction of extension of the parking spaces on both sides, as follows. Figure 3 As shown, the permanent lateral force resisting vertical members 24 arranged in this way only occupy some empty areas around the original basement, and have almost no impact on the building function, thus maximizing the utilization efficiency of the basement.

[0064] Example 2

[0065] This embodiment further proposes a construction method based on the above-mentioned foundation pit retaining system, as described in Embodiment 1. Figure 2 As shown, the temporary horizontal support structure includes at least a first horizontal support structure 21 and a second horizontal support structure 22. The construction method specifically includes the following steps:

[0066] S1. Construct the retaining structure 1 and permanent lateral force resisting vertical members 24 for the foundation pit according to the design drawings, and at the same time construct the pile foundation of the main structure as needed;

[0067] S2. Excavate the soil inside the foundation pit between the ground surface and the first horizontal support structure 21;

[0068] S3. Construct the first horizontal support structure 21 and complete the connection between the first horizontal support structure 21 and the retaining structure 1 and the permanent lateral force resisting vertical member 24.

[0069] S4. After the strength of the first horizontal support structure 21 reaches the required level, excavate the soil inside the foundation pit between the first horizontal support structure 21 and the second horizontal support structure 22.

[0070] S5. Construct the second horizontal support structure 22 and complete the connection between the second horizontal support structure 22 and the retaining structure 1 and the permanent lateral force resisting vertical member 24.

[0071] S6. Repeat steps S4 to S5 until the last horizontal support structure is completed. Then, excavate the soil from the last horizontal support structure down to the foundation pit until the earthwork excavation is completed.

[0072] Preferably, a support plate that can serve as a construction site is provided in the first horizontal support structure 21 and / or the second horizontal support structure 22. This facilitates construction and allows for the application of counterweight to the permanent lateral force resisting vertical member 24, thereby increasing the lateral bearing capacity of the vertical member and improving the safety of the foundation pit retaining structure.

[0073] S7. Construct the basement floor slab 43 and complete the anchorage connection between the floor slab 43 and the retaining structure 1 and the permanent lateral force resisting vertical member 24;

[0074] S8. Sequentially dismantle the temporary support structure, and simultaneously construct multiple structural columns 5, basement interior floor slabs 42 and basement exterior walls 41, and then construct the basement roof slab.

[0075] S9, the gap between the backfill pit retaining structure 1 and the basement exterior wall 41.

[0076] In summary, in the above embodiments, most of the basement main structure is still constructed using the traditional sequential construction method, which has mature construction procedures and low cost. To meet the performance requirements of the foundation pit support, the lateral force resisting vertical members 24 are designed with a continuous stress section with a high aspect ratio in the lateral direction. This greatly increases the lateral stiffness of the members, thereby improving the overall support capacity of the foundation pit retaining system. Furthermore, the foundation pit retaining system has good flexibility for later modifications. After the earthwork excavation is completed, multiple structural columns 5 can be constructed in the surrounding area as needed using the sequential construction method. These structural columns 5 and multiple sets of permanent lateral force resisting vertical members 24 are staggered in this surrounding area, which reduces the span between adjacent vertical members in this area, thereby reducing the height of the beam 6.

[0077] In this specification, the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.

[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A basement foundation pit retaining system with internal support, comprising a retaining structure and temporary horizontal support structures and permanent vertical support structures supporting the retaining structure along the perimeter of the foundation pit, wherein the retaining structure is arranged along the inner wall of the foundation pit, characterized in that: The permanent vertical support structure includes multiple sets of permanent lateral force resisting vertical members with continuous load-bearing sections having a high aspect ratio at least in the lateral direction. The lower ends of the members are anchored below the basement floor slab. The members are constructed using the reverse construction method. During the construction of the basement, they serve as lateral force resisting members for the foundation pit. After construction, they are retained in the perimeter area inside the basement as part of the vertical load-bearing members of the basement. In this perimeter area, multiple structural columns are also constructed using the forward construction method. The multiple structural columns and the multiple sets of permanent lateral force resisting vertical members are arranged in an alternating manner in this perimeter area.

2. The internally supported basement foundation pit retaining system according to claim 1, characterized in that, The permanent lateral force resisting vertical members are made of reinforced concrete, steel, or a combination of reinforced concrete and steel; the temporary horizontal support structure is made of reinforced concrete, steel, or a combination of reinforced concrete and steel.

3. The internally supported basement pit retaining system according to claim 1, characterized in that, The permanent lateral force resisting vertical member is composed of multiple pile foundations arranged in a horizontal line; and / or the permanent lateral force resisting vertical member is formed by multiple vertical bearing piles arranged in a horizontal direction constrained by a steel structure.

4. The internally supported basement pit retaining system according to claim 1, characterized in that, The permanent lateral force resisting vertical members are arranged in the form of a straight wall.

5. The internally supported basement foundation pit retaining system according to claim 1, characterized in that, The permanent lateral force resisting vertical members have their stiffness improved by taking prestressing measures; the temporary horizontal support structure coordinates the deformation of the pit side by taking prestressing measures.

6. The internally supported basement pit retaining system according to claim 1, characterized in that, The permanent lateral force resisting vertical members have their lateral force resisting capacity enhanced by taking counterweight measures.

7. The internally supported basement pit retaining system according to claim 1, characterized in that, The retaining structure includes multiple vertical support members, and the temporary horizontal support structure includes multiple temporary lateral force resisting horizontal members. The vertical support members and / or the temporary lateral force resisting horizontal members are removable and reusable members.

8. The internally supported basement pit retaining system according to claim 7, characterized in that, The temporary horizontal support structure also includes a support plate, which is connected to a temporary lateral force resisting horizontal member, and the surface of the support plate is suitable for providing a construction work site.

9. The internally supported basement pit retaining system according to claim 1, characterized in that, After the basement construction is completed, the permanent lateral force resisting vertical members are located inside the basement exterior wall and are arranged perpendicular to the basement exterior wall.

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