Foundation Pit Support Structure and Construction Method

Abstract

This invention discloses a foundation pit support structure and a construction method for foundation pit support. The foundation pit support structure includes retaining piles, support foundations, and diagonal braces. Multiple retaining piles are arranged at intervals along the edge of the foundation pit. Multiple support foundations are located at the bottom of the foundation pit, with each support foundation corresponding to one side of a retaining pile. Each support foundation includes a pile cap and a set of steel pipe piles. The steel pipe piles are inserted into the ground at the bottom of the foundation pit, and the pile cap is fixedly installed on top of the steel pipe piles. The diagonal braces are inclined, with the upper end connected to the upper part of the retaining piles and the lower end connected to the pile cap. Multiple diagonal braces are provided, and each support foundation and its corresponding retaining pile are connected by a diagonal brace. This foundation pit support structure allows for support of the foundation pit edge before the construction of the basement floor slab, and also facilitates the excavation of the counterweight soil pile during construction, thus improving construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a foundation pit support structure and a foundation pit support construction method. Background Technology

[0002] During the construction of underground structures such as basements, it is necessary to excavate a foundation pit and install a supporting structure to protect the edges of the pit to prevent collapse during basement construction. To install this supporting structure, the relevant technology first constructs retaining piles at the corresponding edge of the pit, then excavates the pit, leaving a backfill mound to press against one side of the retaining piles. Next, the basement floor slab is constructed on the excavated portion of the pit, followed by the construction of raised reaction piers on the basement floor slab. Then, diagonal braces are installed, with their ends connected to the retaining piles and reaction piers respectively. Finally, the backfill mound needs to be excavated to allow for subsequent construction of the remaining basement floor slab and exterior walls. However, this foundation pit supporting structure and its construction process have several drawbacks. Firstly, because the reaction piers can only be constructed after the basement floor slab is completed, the support of the diagonal braces for the pit edge is delayed. Secondly, when excavating the backfill mound, the area available for excavation is narrow due to the need to protect the already constructed basement floor slab, hindering excavation and impacting construction efficiency. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a foundation pit support structure, which can provide support for the edge of the foundation pit before the construction of the basement floor slab, and also facilitates the excavation of the counterweight soil pile during construction, thereby improving construction efficiency.

[0004] The present invention also provides a method for constructing foundation pit supports for the construction of the aforementioned foundation pit support structure.

[0005] According to a first aspect of the present invention, a foundation pit support structure includes retaining piles, support foundations, and diagonal braces; multiple retaining piles are provided and arranged at intervals along the edge of the foundation pit; multiple support foundations are provided and located at the bottom of the foundation pit, and each support foundation is correspondingly provided on one side of a retaining pile; each support foundation includes a pile cap and a set of steel pipe piles, the steel pipe piles are inserted into the ground at the bottom of the foundation pit, and the pile cap is fixedly provided on the top of the steel pipe piles; the diagonal braces are inclined, and the upper end of the diagonal braces is connected to the upper part of the retaining piles, and the lower end of the diagonal braces is connected to the pile cap; multiple diagonal braces are provided, and each support foundation and its corresponding retaining pile are connected by a diagonal brace.

[0006] The foundation pit support structure according to the first aspect of the present invention has at least the following beneficial effects:

[0007] The foundation pit support structure of this invention sets steel pipe piles at the bottom of the foundation pit and sets a pile cap on top of the steel pipe piles. The pile cap and steel pipe piles together form a stable support structure to support the lower end of the diagonal brace, thus eliminating the need for the basement floor slab and reaction piers to support the diagonal brace. Therefore, the foundation pit support structure of this invention can, on the one hand, provide support for the edge of the foundation pit before the construction of the basement floor slab, thereby improving safety. On the other hand, when the counterweight soil pile needs to be excavated after the diagonal brace is installed, the excavation of the counterweight soil pile will not be affected by the already constructed basement floor slab, which is beneficial to improving construction efficiency.

[0008] According to some embodiments of the first aspect of the present invention, a foundation pit support structure has a first water-stop steel plate pre-embedded on the four sides of the foundation, and the first water-stop steel plate protrudes from the surface of the foundation. A basement floor slab is provided at the bottom of the foundation pit, and the basement floor slab covers the four sides of the foundation and the first water-stop steel plate.

[0009] According to some embodiments of the first aspect of the present invention, the foundation pit support structure has an upper surface of the basement floor slab that is higher than the upper surface of the foundation, and the basement floor slab forms a secondary pouring cavity above the foundation. The perimeter walls of the secondary pouring cavity are fitted with a second water-stop steel plate, and the second water-stop steel plate extends into the interior of the secondary pouring cavity.

[0010] According to some embodiments of the first aspect of the present invention, a foundation pit support structure is provided inside the foundation pit, and the foundation pit exterior wall is located between the support pile and the support foundation. The diagonal brace includes a first section, a second section and a first connector. The first connector is used to be embedded in the foundation pit exterior wall and its two ends can extend out of the surface of the foundation pit exterior wall. The first section is located between the support pile and the foundation pit exterior wall, and its two ends are detachably connected to the support pile and the first connector, respectively. The second section is located between the support foundation and the foundation pit exterior wall, and its two ends are detachably connected to the support foundation and the first connector, respectively.

[0011] According to some embodiments of the first aspect of the present invention, a foundation pit support structure is provided with a third water-stop steel plate in the middle of the first connector, and the third water-stop steel plate is used to be embedded in the interior of the basement exterior wall.

[0012] According to some embodiments of the first aspect of the present invention, the foundation of the foundation further includes a second connector, which is embedded in the foundation and protrudes from the upper surface of the foundation. The second section is provided with a connecting part at one end away from the first connector and is detachably connected to the second connector through the connecting part.

[0013] A method for constructing foundation pit supports according to some embodiments of a second aspect of the present invention includes the following steps:

[0014] Multiple support piles are constructed at intervals along the edge of the foundation pit at the corresponding edge location;

[0015] Excavate the foundation pit and construct multiple sets of steel pipe piles on the side of the support piles closest to the foundation pit. When excavating the foundation pit, reserve a counterweight soil mound on one side of the support piles. Each set of steel pipe piles is located on one side of a support pile, and the counterweight soil mound is located between the steel pipe piles and the support piles.

[0016] A pile cap is constructed on top of each group of steel pipe piles;

[0017] Install diagonal bracing one by one between each foundation and its corresponding support pile along the extension direction of the foundation pit edge; and after each diagonal bracing is installed, excavate the corresponding counterweight soil pile below it before installing the next diagonal bracing.

[0018] The foundation pit support construction method according to some embodiments of the second aspect of the present invention has at least the following beneficial effects:

[0019] The foundation pit support construction method of this invention involves first setting steel pipe piles on the ground at the bottom of the foundation pit, and then setting a pile cap on top of the steel pipe piles. The pile cap and steel pipe piles together form a stable support structure to support the lower end of the diagonal bracing during subsequent installation. Therefore, the foundation pit support structure constructed using this method does not require the basement floor slab and reaction piers to support the diagonal bracing. Thus, the foundation pit support method of this invention can, on the one hand, achieve support for the edge of the foundation pit before the basement floor slab is constructed, thereby improving safety; on the other hand, when excavating the counterweight soil after the diagonal bracing is installed, the excavation of the counterweight soil will not be affected by the already constructed basement floor slab, which is beneficial to improving construction efficiency.

[0020] According to some embodiments of the second aspect of the present invention, in the construction of the foundation pit support method, during the construction of the foundation, a first water-stop steel plate is pre-embedded on the four sides of the foundation, and the first water-stop steel plate protrudes from the surface of the foundation.

[0021] The construction method also includes the following steps:

[0022] The basement floor slab is constructed at the bottom of the foundation pit, and a second water-stop steel plate is pre-embedded in the basement floor slab. The basement floor slab covers the perimeter of the foundation and the first water-stop steel plate, and the upper surface of the basement floor slab is higher than the upper surface of the foundation, so that the basement floor slab forms a secondary pouring cavity above the foundation. The second water-stop steel plate is pre-embedded in the perimeter of the secondary pouring cavity and extends into the secondary pouring cavity.

[0023] According to some embodiments of the second aspect of the present invention, the foundation pit support construction method includes a diagonal brace comprising a first segment, a first connector, and a second segment connected in sequence. The construction method further includes the following steps:

[0024] A third water-stop steel plate is installed at the middle of the first connector, corresponding to the position of the basement exterior wall;

[0025] Construct the basement exterior wall, and embed the middle part of the first connector and the third water-stop steel plate inside the basement exterior wall.

[0026] The foundation pit support construction method according to some embodiments of the second aspect of the present invention further includes the following steps:

[0027] Backfill the area between the support piles and the basement exterior wall;

[0028] Before the earthwork is backfilled to the height of the first connector, the first connector is cut on the inside and outside of the basement exterior wall respectively;

[0029] The first section was removed from the support piles and the second section was removed from the pile cap, in preparation for the next cycle of use;

[0030] Concrete is poured into the secondary casting cavity to form a repair section that fills the secondary casting cavity.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0033] Figure 1 This is a side view of a foundation pit support structure according to one embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the connection structure between the supporting foundation, the second section, and the basement floor slab in one embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the structure of the second segment in one embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the connection structure between the main body of the second segment and the first segment in one embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram showing the state of the foundation pit support structure construction process after the construction of the support piles, excavation of the foundation pit and steel pipe piles, but before the installation of the diagonal bracing.

[0038] Figure label:

[0039] Support pile 110; corbel 111; cap beam 120; support and water-stop structure 130; pile cap 210; first water-stop steel plate 211; steel pipe pile 220; second connector 230; diagonal brace 300; first section 310; lacing plate 311; reinforcing lacing plate 312; second connecting hole 313; end sealing plate 314; second section 320; main body 321; connecting part 322; bottom plate 323; triangular plate 324; first end plate 325; second end plate 326; first connector 330; third water-stop steel 340; basement floor slab 400; secondary pouring cavity 410; second water-stop steel plate 411; basement exterior wall 500; counterweight soil mound 600. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, left, right, front, back, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0042] In the description of this invention, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0043] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0044] The following is for reference only. Figure 1 To be continued Figure 4 This describes the foundation pit support structure according to a first aspect embodiment of the present invention.

[0045] Reference Figure 1 According to some embodiments of the present invention, the foundation pit support structure includes support piles 110, support foundations, and diagonal braces 300; wherein, multiple support piles 110 are provided and arranged at intervals along the edge of the foundation pit (the extension direction of the foundation pit edge is perpendicular to the ground). Figure 1(See the drawing). The retaining piles 110 are used to limit the collapse of the soil at the edge of the foundation pit into the pit. Multiple support foundations are set at the bottom of the foundation pit, and each support foundation is set on one side of a multiple retaining piles 110. The diagonal braces 300 are set at an inclination, with the upper end connected to the upper part of the retaining piles 110 and the lower end connected to the support foundation. Furthermore, each support foundation and its corresponding retaining piles 110 are connected by diagonal braces 300, so as to provide further support to the retaining piles 110 with the help of the diagonal braces 300, so as to avoid the retaining piles 110 bending, deforming or being damaged under the lateral pressure of the soil.

[0046] Reference Figure 1 The supporting foundation includes a pile cap 210 and a set of steel pipe piles 220. The steel pipe piles 220 are inserted into the ground at the bottom of the foundation pit to firmly anchor the entire supporting foundation to the ground at the bottom of the foundation pit. The pile cap 210 is set on top of the steel pipe piles 220 and is used to connect to and support the lower end of the corresponding diagonal brace 300.

[0047] It should be understood that, compared to the method of using the basement slab 400 and reaction piers as the supporting foundation, the foundation pit support structure of this embodiment of the invention is constructed by setting steel pipe piles 220 on the ground at the bottom of the foundation pit and setting a pile cap 210 on the top of the steel pipe piles 220. Thus, the pile cap 210 and the steel pipe piles 220 together form a stable support structure to support the lower end of the diagonal brace 300. Therefore, it is not necessary to use the basement slab 400 and reaction piers to support the diagonal brace 300. On the one hand, the support of the foundation pit edge can be achieved before the construction of the basement slab 400, thereby improving safety. On the other hand, after the diagonal brace 300 is installed, the subsequent excavation of the counterweight soil pile 600 will not be affected by the already constructed basement slab 400, which is conducive to improving construction efficiency.

[0048] It is understood that, in some of these embodiments, reference is made to... Figure 1 Each group of steel pipe piles 220 includes multiple vertically arranged vertical piles and multiple inclined piles. The vertical piles are inserted vertically into the ground at the bottom of the foundation pit so that the pile cap 210 can be firmly fixed to the ground. The inclined piles are inserted into the ground at an angle parallel to the inclined brace 300, and the inclined piles are located on the side of the pile cap 210 away from the support piles 110 so that the supporting foundation can better provide the reaction force of the inclined brace 300 and prevent the pile cap 210 from shifting under the thrust of the inclined brace 300.

[0049] It is understood that, in some of these embodiments, reference is made to... Figure 1 The top of the support pile 110 is provided with a capping beam 120 extending along the edge of the foundation pit, and the support pile 110 and the capping beam 120 are provided with a support and water-stopping structure 130 on the side away from the foundation pit to prevent the soil at the edge of the foundation pit from seeping into the inside of the foundation pit.

[0050] It is understandable that after the installation of the diagonal brace 300 is completed, the basement floor slab 400 will be constructed at the bottom of the foundation pit. Furthermore, to prevent leakage at the location of the supporting foundation corresponding to the basement floor slab 400 after its construction, in some embodiments, reference is made to... Figure 2 The foundation 210 has a first water-stop steel plate 211 embedded on its four sides, and the first water-stop steel plate 211 protrudes from the surface of the foundation 210. The basement floor 400 covers the foundation 210 and the first water-stop steel plate 211. That is, after the basement floor 400 is constructed, the foundation 210 will be spliced ​​with the basement floor 400 to form a whole, and the first water-stop steel plate 211 will be embedded in the interior of the basement floor 400, thereby preventing leakage from the splice between the foundation 210 and the basement floor 400.

[0051] It is understood that, in some of these embodiments, reference is made to... Figure 2 The height of the upper surface of the foundation 210 is set lower than the height of the upper surface of the basement slab 400. That is, after the construction of the basement slab 400 is completed, the foundation 210 will be recessed into the upper surface of the basement slab 400, so that the basement slab 400 forms a secondary pouring cavity 410 above the foundation 210. After the basement structure construction is completed and the diagonal bracing 300 is removed, concrete is poured again in the secondary pouring cavity 410 to form a repair part to fill the secondary pouring cavity 410, so that the basement slab 400 is flatter and the supporting foundation composed of the foundation 210 and steel pipe piles 220 can be covered by the basement slab 400 and the repair part.

[0052] It should be understood that in the related technologies that use the basement floor slab 400 and reaction piers as the supporting foundation, the reaction piers need to be removed after the basement structure is completed. Therefore, the construction process is not only relatively troublesome, but also generates construction waste. In this embodiment, the pile cap 210 and steel pipe piles 220 that participate in forming the supporting foundation will be covered by the basement floor slab 400 and the repair section after the basement structure is completed. Therefore, they do not need to be removed. This makes the construction process more convenient and more environmentally friendly.

[0053] It is understood that, in some of these embodiments, reference is made to... Figure 2 The basement floor slab 400 is fitted with a second water-stop steel plate 411 at the position of the cavity wall around the secondary pouring cavity 410, and the second water-stop steel plate 411 extends into the interior of the secondary pouring cavity 410. So when the repair part is poured, the part of the second water-stop steel plate 411 inside the secondary pouring cavity 410 will be embedded into the repair part, thereby preventing leakage from the joint between the repair part and the basement floor slab 400 and further improving the anti-leakage performance.

[0054] After the basement floor slab 400 at the bottom of the foundation pit is completed, the basement exterior wall 500 will need to be constructed inside the foundation pit. The basement exterior wall 500 facing the support pile 110 will be located between the support pile 110 and the supporting foundation. After the basement exterior wall 500 is constructed, the diagonal brace 300 will be installed through the basement exterior wall 500. In related technologies, when constructing the basement exterior wall 500, a clearance window needs to be reserved at the position of the corresponding diagonal brace 300, and the size of the clearance window is larger than the size of the diagonal brace 300, so as to facilitate the subsequent removal of the diagonal brace 300. After the diagonal brace 300 is removed, the clearance window also needs to be repaired. The subsequent repair of the basement exterior wall 500 is not only difficult to construct, but also has a great risk of leakage.

[0055] To avoid the aforementioned leakage problem in the basement exterior wall 500, in some embodiments, reference is made to... Figure 1The diagonal brace 300 is segmented, including a first segment 310, a second segment 320, and a first connector 330. The first connector 330 is embedded in the basement exterior wall 500, and its length is greater than the thickness of the basement exterior wall 500, so that after the basement exterior wall 500 is constructed, both ends of the first connector 330 can extend beyond the surface of the basement exterior wall 500 to facilitate the connection between the first segment 310 and the second segment 320. The first segment 310 is used to connect the support pile 110, and both ends of the first segment 310 are detachably connected to the support pile 110 and the first connector 320, respectively. The first segment 310 is positioned between the support pile 110 and the basement exterior wall 500 after the basement exterior wall 500 is constructed, with connector 330. Correspondingly, the second segment 320 is used to connect the supporting foundation, and both ends of the second segment 320 are detachably connected to the pile cap 210 and the first connector 330, respectively, so that after the basement exterior wall 500 is constructed, the second segment 320 is positioned between the supporting foundation and the basement exterior wall 500. With the above structure, when the diagonal bracing needs to be removed after the basement exterior wall 500 is constructed, the first connector 330 can be cut on the inner and outer sides of the basement exterior wall 500, respectively. This arrangement ensures that the middle portion of the first connector 330 remains within the basement exterior wall 500 and becomes part of it, thus avoiding any opening in the basement exterior wall 500. The two ends of the first connector 330 are separated from the basement exterior wall 500 along with the first segment 310 and the second segment 320, respectively. Since the first segment 310 is detachably connected to the first connector 330 and the support pile 110, and the second end is detachably connected to the first connector 330 and the foundation 210, the first segment 310 is removed from the support pile 110, and the first connector 330 is disconnected from the first segment 310. The remaining end of section 10 is removed from the foundation 210. The remaining end of the first connector 330 connected to the second section 320 is also removed, thus completing the removal of the first section 310 and the second section 320. This allows the first section 310 and the second section 320 to be recycled for the next construction of the foundation pit support structure. At the same time, since the basement exterior wall 500 does not need to be equipped with a clearance window, and the middle part of the first connector 330 is retained in the basement exterior wall 500, there is no need to repair the basement exterior wall 500 later. This is beneficial to improving construction efficiency and effectively reducing the risk of leakage.

[0056] It is understood that, in some of these embodiments, reference is made to... Figure 1A third water-stop steel plate 340 is provided on the first connector 330, and the third water-stop steel plate 340 is located in the middle of the first connector 330, so that the third water-stop steel plate 340 can be embedded inside the basement exterior wall 500 during construction, thereby preventing leakage on the periphery where the first connector 330 abuts against the basement exterior wall 500, and further improving the anti-leakage effect of the basement exterior wall 500.

[0057] It is understandable that, in order to facilitate the detachable connection between the diagonal brace 300 and the bearing platform 210, in some embodiments, reference is made to... Figure 2 The supporting foundation also includes a second connector 230, which is embedded in the foundation 210 and protrudes from the upper surface of the foundation 210. The second segment 320 is provided with a connecting part 322 at the end opposite to the first connector 330. The second segment 320 is detachably connected to the second connector 230 through the connecting part 322.

[0058] It is understood that, in some of these embodiments, reference is made to... Figure 2 The second section 320 also includes a main body 321, with a connecting part 322 located at one end of the main body 321. The main body 321 is detachably connected to the first connecting member 330. Specifically, to facilitate the installation and removal of the connecting part 322 on the bearing platform 210, the second connecting member 230 is a pre-embedded bolt, and the connecting part 322 is provided with a first connecting hole for cooperating with the pre-embedded bolt. The connecting part 322 is sleeved on the pre-embedded bolt through the first connecting hole and is pressed and fixed on the bearing platform 210 by a nut that cooperates with the pre-embedded bolt.

[0059] In some embodiments, specifically, reference is made to Figure 3 The connecting part 322 is welded from multiple metal plates and includes a bottom plate 323, multiple triangular plates 324, a first end plate 325, and a second end plate 326. The bottom plate 323 has a first connecting hole for fitting against the upper surface of the support platform 210. The multiple triangular plates 324 extend along the width direction of the bottom plate 323 (perpendicular to...). Figure 3 The triangle plates 324 are arranged at intervals in the diagram, and the long side of the triangle plates 324 is attached to the bottom plate 323 and is set vertically. The first end plate 325 is connected to the short side of each triangle plate 324 facing the support pile 110, and the second end plate 326 is connected to the other remaining side of each triangle plate 324.

[0060] It is understood that in some embodiments, the main body 321 of the second segment 320 is detachably connected to the first end plate 325 by bolts or other connecting parts; or in other embodiments, the main body 321 of the second segment 320 is welded to the first end plate 325.

[0061] It is understood that, in some of these embodiments, reference is made to... Figure 1 To facilitate the connection between the support pile 110 and the first section 310, the upper part of the support pile 110 is connected to the bracket 111, and the first section 310 can be detachably connected to the bracket 111 by bolts or other connecting parts.

[0062] It is understood that, in some of these embodiments, reference is made to... Figure 4 The first segment 310 adopts a lattice column, and a reinforcing lacing plate 312 is superimposed and attached to the lacing plate 311 at the end of the lattice column near the first connector 330. The first connector 330 is a connecting steel bar with threaded ends. A second connecting hole 313 is provided on the lacing plate 311 and the reinforcing lacing plate 312 near the first connector 330 of the lattice column, allowing the connecting steel bar to pass through. The lacing plate 311 and the reinforcing lacing plate 312 are fixed to the connecting steel bar by nuts that are threaded to the connecting steel bar. The lattice column of the first segment 310 is connected to the bracket 111 by an end sealing plate 314 near the bracket 111.

[0063] Furthermore, referring to Figure 4 Similarly, the structure of the main body 321 in the second segment 320 is similar to that of the first segment 310. The difference is that the lattice column constituting the main body 321 is connected to the connecting part 322 by the end sealing plate 314 near the connecting part 322.

[0064] It should be understood that the first section 310 and the second section 320 can be manufactured in the factory or on-site processing plant before the construction of the foundation pit support structure, or the first section 310, the main body 321 and the connecting part 322 can be manufactured in the factory or on-site processing plant in advance, and then the connection between the main body 321 and the connecting part 322 can be completed when the diagonal brace 300 is installed on the pier.

[0065] The following describes a foundation pit support construction method according to a second aspect of the present invention, for use in implementing the foundation pit support structure described in the first aspect of the present invention.

[0066] The foundation pit support construction method according to a second aspect of the present invention includes the following steps S100 to S400.

[0067] S100, Construct multiple support piles 110 spaced along the edge of the foundation pit at the corresponding edge of the foundation pit;

[0068] S200, excavate the foundation pit, and construct multiple sets of steel pipe piles 220 on the side of the support piles 110 near the foundation pit, and reserve a counterweight soil mound on one side of the support piles 110 during the excavation of the foundation pit; wherein, each set of steel pipe piles 220 is located on one side of a support pile 110, and, referring to Figure 5 The counterweight soil mound 600 is located between the steel pipe pile 220 and the support pile 110;

[0069] S300, A pile cap 210 is constructed on top of each group of steel pipe piles 220;

[0070] S400, install diagonal bracing 300 one by one between each pier cap 210 and its corresponding support pile 110 along the extension direction of the foundation pit edge. After each diagonal bracing 300 is installed, the corresponding counterweight soil pile 600 below it is excavated, and then the next diagonal bracing 300 is installed.

[0071] It is understood that the foundation pit support construction method of this embodiment of the invention first sets up steel pipe piles 220 on the ground at the bottom of the foundation pit, and then sets up a pile cap 210 on top of the steel pipe piles 220. Thus, the pile cap 210 and the steel pipe piles 220 together form a stable support structure to support the lower end of the diagonal brace 300 during subsequent installation. Therefore, the foundation pit support structure constructed by this method does not need to rely on the basement floor slab 400 and reaction piers to support the diagonal brace 300. Thus, the foundation pit support method of this embodiment of the invention can, on the one hand, allow for the construction of the basement floor slab 400... Pre-construction support of the foundation pit edge enhances safety. Furthermore, after the installation of the diagonal brace 300, the excavation of the counterweight soil pile 600 is not affected by the already constructed basement floor slab 400, thus improving construction efficiency. Simultaneously, since the counterweight soil pile 600 below each diagonal brace 300 is excavated after installation before installing the next diagonal brace 300, each counterweight soil pile 600 below each diagonal brace 300 has sufficient working area for excavation, further improving construction efficiency.

[0072] It is understandable that in the above step S100, in addition to the construction of the support piles 110, in order to prevent the soil at the edge of the foundation pit from seeping into the inside of the foundation pit, it is also necessary to construct a capping beam 120 on the top of the support piles 110, and to construct a waterproof support structure 130 on the side of the capping beam 120 and the support piles 110 away from the foundation pit.

[0073] It is understandable that, regarding step S200 above, in some embodiments, the foundation pit is excavated first, and then the steel pipe piles 220 are constructed, in order to avoid damaging the steel pipe piles 220 during the excavation of the foundation pit, and no additional protective measures are required for the steel pipe piles 220. It should also be understood that, in other embodiments, the construction of the steel pipe piles 220 can also be chosen to be carried out before the excavation of the foundation pit, and protective measures should be taken for the steel pipe piles 220 during the excavation of the foundation pit.

[0074] It is understood that, regarding the above step S300, in some embodiments, during the construction of the foundation 210, when pouring the foundation 210, a first water-stop steel plate 211 is pre-embedded on the four sides of the foundation 210, and the first water-stop steel plate 211 protrudes from the surface of the foundation 210, so that it can be better integrated with the basement floor 400 to prevent leakage during the subsequent construction of the basement floor 400.

[0075] For example, in some embodiments, the foundation pit support construction method further includes the following step S500.

[0076] S500, construct the basement floor slab 400 at the bottom of the foundation pit, and make the basement floor slab 400 cover the perimeter of the foundation 210 and the first waterstop steel plate 211.

[0077] Through the above steps S500, the foundation 210 and the basement floor 400 can be integrated into a whole, and leakage can be avoided at the joint between the foundation 210 and the basement floor 400.

[0078] It is understood that, regarding the above step S500, in some embodiments of the present invention, when constructing the basement floor slab 400, the upper surface of the basement floor slab 400 is made higher than the upper surface of the foundation 210, thereby forming a secondary pouring cavity 410 above the foundation 210. Furthermore, when pouring the basement floor slab 400, a second water-stop steel plate 411 is pre-embedded at the position corresponding to the cavity wall around the secondary pouring cavity 410, and the second water-stop steel plate 411 can extend into the interior of the secondary pouring cavity 410.

[0079] It should be understood that the secondary pouring cavity 410 is used to pour concrete again after the diagonal brace 300 is removed, so as to form a repair part to fill the secondary pouring cavity 410, making the basement floor slab 400 more flat. The second water-stop steel plate 411 can prevent leakage from the joint between the repair part and the basement floor slab 400, further improving the anti-leakage performance.

[0080] It should be understood that, regarding step S300, in some embodiments, a first connector 330 is pre-embedded on the top of the foundation 210 during the casting of the foundation 210, so as to facilitate the subsequent connection of the diagonal brace 300 through the first connector 330.

[0081] Understandably, to prevent water seepage in the basement exterior wall 500 caused by the diagonal brace 300 penetrating the wall, in some embodiments, the diagonal brace 300 is configured in a segmented form, including a first segment 310, a first connector 330, and a second segment 320 connected in sequence, and the above step S400 includes the following steps:

[0082] S410. Connect the second section 320 to the corresponding pier 210;

[0083] S420, Connect one end of the first connector 330 to the end of the second section 320 away from the pier 210;

[0084] S430, Connect the two ends of the first section 310 to the other end of the first connector 330 and the corbel 111 of the corresponding support pile 110 respectively;

[0085] S440. Remove the counter-pressure soil pile 600 below the diagonal brace 400 that has been installed this time;

[0086] S450. Repeat steps S410 to S440 above to complete the installation of the next diagonal brace 300, and continue until all diagonal braces 300 are installed.

[0087] If the first section 310, the main body 321, and the connecting part 322 are manufactured in advance at the factory (or on-site processing plant), and the connecting part 322 is connected to the main body 321 by bolts, then regarding step S410 above, the main body 321 can be connected to the bearing platform 210 first, and then the main body 321 can be connected to the connecting part 322. However, if the main body 321 and the connecting part 322 are connected by welding, and the first section 310 and the second section 320 are manufactured in advance at the factory, then regarding step S410 above, the connecting part 322 can be directly connected to the bearing platform 210 to complete the connection between the second section 320 and the bearing platform 210.

[0088] It is understood that, based on the above embodiments, the foundation pit support construction method also includes the following steps S600 and S700.

[0089] S600, a third waterstop steel plate 340 is installed at the middle of the first connector 330 at the position corresponding to the basement exterior wall 500;

[0090] S700, construct the basement exterior wall 500, and embed the middle part of the first connector 330 and the third water-stop steel plate 340 inside the basement exterior wall 500.

[0091] It should be understood that the third water-stop steel plate 340 can prevent leakage from occurring on the periphery where the first connector 330 abuts against the basement exterior wall 500.

[0092] It is understood that, based on the above embodiments, the foundation pit support construction method further includes the following steps S800 to S1100.

[0093] S800, backfill the area between the support pile 110 and the basement exterior wall 500;

[0094] S900 Before the earthwork backfill reaches the height of the first connector 330, the first connector 330 is cut on the inner and outer sides of the basement exterior wall 500 respectively, so that the middle part of the first connector 330 and the third waterstop steel plate 340 are retained inside the basement exterior wall 500.

[0095] S1000, Remove the first section 310 from the support pile 110 and the second section 320 from the pile cap 210, for future use;

[0096] S1100, Concrete is poured into the secondary casting cavity 410 to form a repair section that fills the secondary casting cavity 410.

[0097] It should be understood that, regarding the above step S800, before backfilling, the outer side of the basement exterior wall 500 can be coated with anti-rust paint, and a waterproof layer can be constructed after the anti-rust paint is applied, and then the soil can be backfilled; the inner side of the basement exterior wall 500 also needs to be coated with anti-rust paint before the interior and exterior wall surface decoration is carried out.

[0098] It should be understood that when the main body 321 and the connecting part 322 in the second segment 320 are connected to each other by bolts, regarding the removal of the second segment 320 in the above step S1000, the main body 321 can be removed from the connecting part 322 first, and then the connecting part 322 can be removed from the support 210. Both the main body 321 and the connecting part 322 used to constitute the second segment 320 can be reused in the next cycle.

[0099] It is understood that, regarding the above step S1100, in some embodiments, micro-expansion concrete is selected to be used to pour the secondary pouring cavity 410 so that the formed repair layer can better fit with the basement floor slab 400.

[0100] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A foundation pit support structure, characterized in that, include: Multiple support piles are installed and spaced apart along the edge of the foundation pit; The foundation includes multiple supporting foundations located at the bottom of the pit, with each supporting foundation corresponding to one side of a support pile. Each supporting foundation includes a pile cap and a set of steel pipe piles, with the steel pipe piles inserted into the ground at the bottom of the pit and the pile cap fixedly installed on top of the steel pipe piles. The diagonal brace is inclined and its upper end is connected to the upper part of the support pile, and its lower end is connected to the bearing platform; multiple diagonal braces are provided, and each bearing platform and its corresponding support pile are connected by a diagonal brace. The foundation is provided with a first water-stop steel plate embedded in its four sides, and the first water-stop steel plate protrudes from the surface of the foundation. The bottom of the foundation pit is provided with a basement floor slab, which covers the perimeter of the foundation and the first water-stop steel plate. The upper surface of the foundation is lower than the upper surface of the basement floor slab, and the basement floor slab forms a secondary pouring cavity above the foundation. The secondary pouring cavity is surrounded by a second water-stop steel plate, which extends into the interior of the secondary pouring cavity.

2. The foundation pit support structure according to claim 1, characterized in that, The foundation pit is equipped with a basement exterior wall, which is located between the support piles and the supporting foundation. The diagonal brace includes a first section, a second section, and a first connector. The first connector is embedded in the basement exterior wall and its two ends can extend out of the surface of the basement exterior wall. The first section is located between the support piles and the basement exterior wall, and its two ends are detachably connected to the support piles and the first connector, respectively. The second section is located between the supporting foundation and the basement exterior wall, and its two ends are detachably connected to the foundation and the first connector, respectively.

3. The foundation pit support structure according to claim 2, characterized in that, A third water-stop steel plate is provided in the middle of the first connector, and the third water-stop steel plate is used to be embedded in the interior of the basement exterior wall.

4. The foundation pit support structure according to claim 2, characterized in that, The supporting foundation also includes a second connector, which is embedded in the bearing platform and protrudes from the upper surface of the bearing platform. The second section is provided with a connecting part at one end away from the first connector and is detachably connected to the second connector through the connecting part.

5. A method for constructing foundation pit supports, characterized in that, Includes the following steps: Multiple support piles are constructed at intervals along the edge of the foundation pit at the corresponding edge location; Excavate a foundation pit and construct multiple sets of steel pipe piles on the side of the support piles close to the foundation pit. When excavating the foundation pit, a counterweight soil mound is reserved on one side of the support piles. Each set of steel pipe piles is located on one side of the support piles, and the counterweight soil mound is located between the steel pipe piles and the support piles. A pile cap is constructed on top of each group of steel pipe piles; Along the extension direction of the edge of the foundation pit, diagonal braces are installed one by one between each of the foundation caps and their corresponding support piles; and after each diagonal brace is installed, the corresponding counterweight soil pile below it is excavated, and then the next diagonal brace is installed. During the construction of the foundation, a first water-stop steel plate is pre-embedded on the four sides of the foundation, and the first water-stop steel plate protrudes from the surface of the foundation. The foundation pit support construction method also includes the following steps: A basement floor slab is constructed at the bottom of the foundation pit, and a second water-stop steel plate is pre-embedded in the basement floor slab; wherein, the basement floor slab covers the perimeter of the foundation and the first water-stop steel plate, and the upper surface of the basement floor slab is higher than the upper surface of the foundation, so that the basement floor slab forms a secondary pouring cavity above the foundation, and the second water-stop steel plate is pre-embedded in the perimeter cavity wall of the secondary pouring cavity and extends into the interior of the secondary pouring cavity.

6. The foundation pit support construction method according to claim 5, characterized in that, The diagonal brace includes a first section, a first connector, and a second section connected in sequence. The foundation pit support construction method further includes the following steps: A third water-stop steel plate is installed at the middle of the first connector, corresponding to the position of the basement exterior wall; The basement exterior wall is constructed such that the middle part of the first connector and the third water-stop steel plate are embedded inside the basement exterior wall.

7. The foundation pit support construction method according to claim 6, characterized in that, It also includes the following steps: Backfill the area between the support piles and the basement exterior wall; Before the earthwork is backfilled to the height of the first connector, the first connector is cut on the inner and outer sides of the basement exterior wall respectively; The first section is removed from the support pile and the second section is removed from the pile cap for future reuse. Concrete is poured into the secondary casting cavity to form a repair section that fills the secondary casting cavity.

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