Enclosure structure for foundation pit supporting and construction method of enclosure structure

Abstract

The invention relates to an enclosure structure for foundation pit supporting and a construction method of the enclosure structure. The enclosure structure comprises a plurality of enclosure piles, and the enclosure piles are arranged in the circumferential direction of a foundation pit at intervals; when the fender post is in the first state, the fender post comprises a plurality of peripheral steel plates and an inner supporting steel piece, the peripheral steel plates are spliced to form a cylindrical body of the fender post, the supporting steel piece is located in the cylindrical body, and at least part of the position of the supporting steel piece makes contact with or is connected with the peripheral steel plate close to one side of the inner wall of a foundation pit. When the fender post is in the second state, the fender post comprises a peripheral steel plate and an inner supporting steel piece, the peripheral steel plate is arranged close to the inner wall of the foundation pit and supports the inner wall of the foundation pit, and at least part of the position of the supporting steel piece makes contact with or is connected with the peripheral steel plate. The technical problems that the construction efficiency is reduced and the construction cost is increased when an existing foundation pit support is constructed are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit support construction, and further to a retaining structure for foundation pit support and a construction method of the retaining structure, and in particular to an all-steel retaining structure for manually excavated pile foundation pit support and a construction method of the retaining structure. Background Art

[0002] In foundation pit support projects, row pile retaining structures are often used to ensure the safety and stability of the pit during use. However, construction is often restricted by the surrounding environment and limited working space, which makes it difficult for large construction equipment to operate normally. Manual bored piles are widely used because they do not require complex large-scale machinery and have a minimal impact on the surrounding environment.

[0003] Conventional bored piles generally refer to reinforced concrete piles with a large diameter, which are dug by manpower and cast on site. The pile body of the reinforced concrete pile is excavated in sections, and each section requires steps such as formwork support, concrete pouring, and waiting for the concrete strength to be formed. This leads to reduced construction efficiency and extended construction period. Moreover, after the pile body of the reinforced concrete pile is poured, the concrete part will be permanently fixed in place and cannot be recovered, which increases construction losses and is not conducive to cost savings.

[0004] In the related technology, the use of reinforced concrete piles as foundation pit support not only reduces construction efficiency but also increases construction costs. Currently, no effective solution has been given.

[0005] Therefore, the present invention proposes a retaining structure for foundation pit support and a construction method of the retaining structure to overcome the defects of the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a retaining structure for foundation pit support and a construction method of the retaining structure. The all-steel retaining structure can provide stable support for the foundation pit, and there is no need to wait for the curing and forming of the retaining wall, which greatly shortens the construction time, helps to speed up the construction progress, and has better safety and construction convenience.

[0007] Another object of the present invention is to provide a retaining structure for foundation pit support and a construction method of the retaining structure, wherein at least part of the steel structure can be dismantled along with the excavation of the foundation pit, thereby realizing the recycling and reuse of part of the retaining structure, effectively reducing material waste and lowering construction costs.

[0008] The purpose of the present invention can be achieved by adopting the following scheme:

[0009] The present invention provides a retaining structure for foundation pit support, the retaining structure for foundation pit support comprising a plurality of retaining piles located in soil and supporting the inner wall of the foundation pit, wherein the plurality of retaining piles are arranged at intervals along the circumference of the foundation pit;

[0010] The retaining pile has a first state and a second state,

[0011] When the retaining pile is in the first state, the retaining pile includes a plurality of outer steel plates and an inner supporting steel member, the plurality of outer steel plates are spliced ​​together to form a cylindrical body of the retaining pile, the inner supporting steel member is located inside the cylindrical body, and at least a portion of the inner supporting steel member is in contact with or connected to the outer steel plates close to the inner wall of the foundation pit;

[0012] When the retaining pile is in the second state, the retaining pile includes an outer steel plate and an inner supporting steel member. The outer steel plate is arranged close to the inner wall of the foundation pit and supports the inner wall of the foundation pit. The inner supporting steel member is in contact with or connected to the outer steel plate at least in part.

[0013] In a preferred embodiment of the present invention, two opposite side edges of the outer steel plate are respectively formed with an insert and a slot. When a plurality of the outer steel plates are spliced ​​together to form the cylindrical body, two circumferentially adjacent outer steel plates are engaged and connected through the insert and the slot.

[0014] In a preferred embodiment of the present invention, when the retaining piles are in the second state, a connecting steel plate is connected between the side edges of two adjacent outer steel plates along the circumference of the foundation pit.

[0015] In a preferred embodiment of the present invention, a waterproof layer is provided on the surfaces of the two adjacent outer steel plates and the surface of the connecting steel plate on the side facing away from the inner wall of the foundation pit.

[0016] In a preferred embodiment of the present invention, one of the top edge and the bottom edge of the outer steel plate is provided with a convex positioning block, and the other is provided with a concave positioning groove;

[0017] Each of the guardrail piles is divided into multiple sections in the vertical direction, and two adjacent sections of the guardrail piles are connected by the aligned positioning blocks and the positioning grooves.

[0018] The present invention provides a construction method of a retaining structure, which is implemented using the retaining structure for foundation pit support described above. The construction method of the retaining structure comprises the following steps:

[0019] Step S1: determining a plurality of pile positions according to a preset foundation pit, each of the pile positions corresponding to a retaining pile;

[0020] Step S2: using outer steel plates to splice together to form a plurality of the retaining piles in a cylindrical body;

[0021] Step S3: pressing the retaining piles into the plurality of pile positions respectively to form pile holes;

[0022] wherein, for each pile position, multiple sections of the retaining piles are pressed in sequence until the retaining pile at the bottom is pressed down to the base position of the pile position;

[0023] Step S4: lowering a plurality of inner supporting steel members into the corresponding pile holes, and making at least a portion of the inner supporting steel members contact or connect with the outer steel plate close to the inner wall of the foundation pit;

[0024] Step S5: injecting filler into each of the pile holes to form the outer steel plate and the inner supporting steel member into an integral body;

[0025] Step S6: excavating a foundation pit within the range enclosed by the plurality of retaining piles, and removing a portion of the outer steel plates within the excavated foundation pit as the depth of the foundation pit increases;

[0026] For each pile position, a plurality of the outer steel plates away from the inner wall of the foundation pit are removed and recovered, and only one outer steel plate close to the inner wall of the foundation pit is retained.

[0027] In a preferred embodiment of the present invention, after step S6, the method further includes:

[0028] Step S7: connecting the side edges of two adjacent outer steel plates in the circumferential direction of the foundation pit using a connecting steel plate;

[0029] Step S8: A waterproof layer is provided on the surfaces of the two adjacent outer steel plates and the surface of the connecting steel plate facing away from the inner wall of the foundation pit.

[0030] In a preferred embodiment of the present invention, before step S3, soil at a plurality of pile positions is excavated for the retaining piles to be pressed into, and pile holes are formed in the cylindrical bodies of the retaining piles.

[0031] Alternatively, after step S3, the soil inside the cylindrical body of the retaining pile is excavated to form a pile hole.

[0032] In a preferred embodiment of the present invention, the outer steel plate is a steel plate with an arc-shaped cross section, and the inner supporting steel member is a vertically arranged steel section;

[0033] In step S4, the inner supporting steel member lowered into the pile hole must satisfy the following requirement: the flange plate of the steel section is parallel to the edge line of the foundation pit.

[0034] In a preferred embodiment of the present invention,

[0035] The step S5 comprises: step S501: injecting a first filler into the base portion of each pile hole and close to the bottom of the foundation pit; wherein the first filler comprises cement slurry, cement mortar or concrete; step S502: injecting a second filler into each pile hole and above the first filler; wherein the second filler comprises plain soil, sand or solidified soil;

[0036] And / or, the step S5 includes injecting a third filler between the retained outer steel plate and the inner supporting steel member; wherein the third filler includes fine stone concrete.

[0037] As described above, the features and advantages of the retaining structure for foundation pit support and the construction method of the retaining structure of the present invention are:

[0038] The present invention provides a novel retaining pile structure, which has a first state and a second state during construction, wherein the first state corresponds to a state in which the retaining pile is pressed downward into the soil, and the second state corresponds to a state in which the foundation pit is excavated after the retaining pile is pressed into the soil. When the retaining pile is in the first state, the retaining pile includes a plurality of outer steel plates and an inner supporting steel member, and the plurality of outer steel plates are spliced ​​together to form a cylindrical body of the retaining pile. The inner supporting steel member is located in the cylindrical body, and at least part of the position of the inner supporting steel member is in contact with or connected to the outer steel plate close to the inner wall of the foundation pit. By cooperating with the cylindrical body and the inner supporting steel member, a stable support for the soil can be achieved, thereby achieving a stable support for the foundation pit. The retaining pile adopts an all-steel structure, which is different from the conventional manual excavation and pouring. The pile construction process of the present invention does not need to wait for the strength of the retaining wall to be formed, which reduces the maintenance time of the conventional manually excavated pile retaining wall, speeds up the excavation progress, is safer, and is more convenient to construct; when the retaining pile is in the second state, the retaining pile includes an outer steel plate and an inner supporting steel member, and multiple outer steel plates away from the inner wall of the foundation pit can be dismantled and recycled, and only one outer steel plate close to the inner wall of the foundation pit is retained, and at least part of the inner supporting steel member is in contact with or connected to the retained outer steel plate, which can meet the support requirements for the foundation pit and can also be dismantled and part of the outer steel plates can be recycled along with the excavation of the foundation pit, effectively reducing material waste and reducing construction costs to achieve higher economic benefits. Moreover, the overall assembled construction is more energy-saving and environmentally friendly.

[0039] In addition, a waterproof layer can be laid on the retaining pile structure, so that the retaining structure of the present invention can simultaneously assume the functions of support and waterproofing, and can be used as "two walls in one". BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0041] in:

[0042] Figure 1 This is a schematic structural diagram of a single retaining pile in a retaining structure for foundation pit support according to the present invention in a first state;

[0043] Figure 2 This is a schematic structural diagram of two adjacent retaining piles in the retaining structure for foundation pit support according to the present invention in a first state;

[0044] Figure 3 Schematic diagram of the structure of two adjacent retaining piles in the retaining structure for foundation pit support of the present invention in the second state;

[0045] Figure 4 This is a schematic structural diagram of the outer steel plate in the enclosure structure for foundation pit support according to the present invention;

[0046] Figure 5 This is a cross-sectional view of a retaining pile in a retaining structure for foundation pit support according to the present invention when the retaining pile is located in a foundation pit in a first state;

[0047] Figure 6 A cross-sectional view of a retaining pile in a retaining structure for foundation pit support according to the present invention when the retaining pile is located in a second state within the foundation pit;

[0048] Figure 7 This is one of the structural schematic diagrams of the retaining structure for foundation pit support of the present invention within the foundation pit;

[0049] Figure 8 This is a second structural schematic diagram of the retaining structure for foundation pit support in the present invention;

[0050] Figure 9 This is a third structural schematic diagram of the retaining structure for foundation pit support in the present invention;

[0051] Figure 10 This is the fourth structural schematic diagram of the retaining structure for foundation pit support in the present invention.

[0052] The accompanying drawings in the present invention are:

[0053] 1. Retaining piles; 101. External steel plate;

[0054] 1011. Insertion block; 1012. Card slot;

[0055] 1013. Positioning block; 1014. Positioning slot;

[0056] 102. Internal supporting steel parts; 103. Connecting steel plates;

[0057] 104. Waterproof layer; 2. First filler;

[0058] 3. Second filler; 4. Third filler;

[0059] 5. Foundation pit; 6. Steel purlin;

[0060] 7. Support beam; 8. Base part. DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0062] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementations.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0064] Implementation Method 1

[0065] like Figures 1 to 10 As shown, the present invention provides a retaining structure for foundation pit support, which includes a plurality of retaining piles 1 located in the soil and supporting the inner wall of the foundation pit 5, and the plurality of retaining piles 1 are spaced and evenly arranged along the circumference of the foundation pit 5. Among them, the retaining pile 1 has a first state and a second state. When the retaining pile 1 is in the first state, the retaining pile 1 includes a plurality of outer steel plates 101 and an inner supporting steel member 102. The plurality of outer steel plates 101 are spliced ​​to form the cylindrical body of the retaining pile 1. The inner supporting steel member 102 is located in the cylindrical body, and at least part of the inner supporting steel member 102 is in contact with or connected to the outer steel plate 101 close to the inner wall of the foundation pit 5; when the retaining pile 1 is in the second state, the retaining pile 1 includes an outer steel plate 101 and an inner supporting steel member 102. The outer steel plate 101 is arranged close to the inner wall of the foundation pit 5 and supports the inner wall of the foundation pit 5. At least part of the inner supporting steel member 102 is in contact with or connected to the outer steel plate 101.

[0066] It can be understood that the second state of the retaining pile 1 in the present invention is formed by the transformation of the first state, that is, after multiple outer steel plates 101 and an inner supporting steel member 102 cooperate to form the first state of the retaining pile 1, the multiple outer steel plates 101 away from the inner wall of the foundation pit 5 can be dismantled and recycled as the foundation pit 5 is excavated, and only one outer steel plate 101 close to the inner wall of the foundation pit 5 is retained, and at least part of the inner supporting steel member 102 is in contact with or connected to the retained outer steel plate 101, thereby forming the second state of the retaining pile 1 through the cooperation of an outer steel plate 101 and an inner supporting steel member 102.

[0067] The present invention provides a novel retaining pile 1 structure, which has a first state and a second state during the construction process, wherein the first state corresponds to the state in which the retaining pile 1 is pressed downward into the soil, and the second state corresponds to the state in which the foundation pit 5 is excavated after the retaining pile 1 is pressed into the soil. When the retaining pile 1 is in the first state, the retaining pile 1 includes a plurality of outer steel plates 101 and an inner supporting steel member 102. The plurality of outer steel plates 101 are spliced ​​to form a cylindrical body of the retaining pile 1. The inner supporting steel member 102 is located in the cylindrical body, and at least part of the position of the inner supporting steel member 102 is in contact with or connected to the outer steel plate 101 close to the inner wall of the foundation pit 5. By cooperating with the cylindrical body and the inner supporting steel member 102, it is possible to achieve stable support for the soil, thereby achieving the effect of stable support for the foundation pit 5. The retaining pile 1 adopts an all-steel structure. Compared with conventional manual digging The bored pile construction process of the present invention does not require waiting for the strength of the retaining wall to be formed, reduces the maintenance time of the conventional manually excavated pile retaining wall, speeds up the excavation progress, is safer, and is more convenient to construct; when the retaining pile 1 is in the second state, the retaining pile 1 includes an outer steel plate 101 and an inner supporting steel part 102, and the multiple outer steel plates 101 away from the inner wall of the foundation pit 5 can be dismantled and recycled, leaving only one outer steel plate 101 close to the inner wall of the foundation pit 5, and at least part of the inner supporting steel part 102 is in contact with or connected to the retained outer steel plate 101, which can meet the support requirements for the foundation pit 5, and can also be dismantled and part of the outer steel plates 101 can be recycled along with the excavation of the foundation pit 5, effectively reducing material waste and reducing construction costs to achieve higher economic benefits, and the overall assembly construction is more energy-saving and environmentally friendly.

[0068] In an optional embodiment of the present invention, Figures 1 to 4 As shown, two opposite side edges of the outer steel plate 101 are respectively formed with an insert block 1011 and a clamping groove 1012. When multiple outer steel plates 101 are spliced ​​together to form a cylindrical body, two circumferentially adjacent outer steel plates 101 are clamped together by the insert block 1011 and the clamping groove 1012. Figure 1 and Figure 4As shown, the outer steel plate 101 is vertically pressed into the soil, and a vertically protruding long strip plug 1011 and a vertically extending slot 1012 are formed on the left and right edges of the outer steel plate 101. When multiple outer steel plates 101 are spliced ​​together to form the cylindrical body of the retaining pile 1, between two adjacent outer steel plates 101, the plug 1011 on the right edge of one outer steel plate 101 is inserted into the slot 1012 on the left edge of the other outer steel plate 101. The plug 1011 and the slot 1012 cooperate to achieve a stable splicing between the outer steel plates 101. The shape and size of the multiple outer steel plates 101 can be set according to the outer diameter of the pile hole to be excavated, so that the cylindrical body formed by splicing multiple outer steel plates 101 can meet the requirements of the pile hole to be excavated.

[0069] In this embodiment, the outer steel plate 101 is a steel plate with an arc-shaped cross-section. The cylindrical body of a retaining pile 1 can be formed by splicing three outer steel plates 101 together to form a cylindrical body, thereby meeting the requirements of the intended pile hole. The vertical length of each outer steel plate 101 can be, but is not limited to, 1 meter, and the thickness of each outer steel plate 101 can be, but is not limited to, 10 mm. The outer diameter of the cylindrical body formed by splicing three outer steel plates 101 can be, but is not limited to, 800 mm. The spacing between adjacent retaining piles 1 along the circumference of the foundation pit 5 can be, but is not limited to, 1200 mm.

[0070] In the present invention, Figures 1 to 3 As shown, the inner support steel member 102 may be, but is not limited to, a vertically arranged steel section. When assembling the steel section with the outer steel plate 101, it is necessary to ensure that both ends of at least one flange plate of the steel section are in contact with or connected to the inner concave surface of the outer steel plate 101. The steel section can support and reinforce the outer steel plate 101, so that the steel section and the outer steel plate 101 form an integral structure, thereby improving the stability of the foundation pit support. The connection relationship between the steel section and the outer steel plate 101 can be selected based on the actual stratum information and the excavation depth of the foundation pit 5. For example, when the stratum stability is poor and / or the excavation depth of the foundation pit 5 is deep and requires more stable support, the steel section and the outer steel plate 101 can be welded to improve the stability of the support. When the stratum stability is high and the excavation depth of the foundation pit 5 is shallow, the steel section and the outer steel plate 101 can be omitted from welding, ensuring that the steel section can contact the outer steel plate 101 and provide support for the outer steel plate 101.

[0071] In an optional embodiment of the present invention, Figure 3 、 Figures 8 to 10As shown, when the retaining pile 1 is in the second state, a connecting steel plate 103 is connected between the side edges of two adjacent outer steel plates 101 along the circumference of the foundation pit 5, thereby connecting the outer steel plates 101 to form a whole along the circumference of the foundation pit 5 to ensure the stability of the entire retaining structure. The connecting steel plate 103 can be connected to the side edges of the two adjacent outer steel plates 101 by welding.

[0072] Further, such as Figure 3 As shown, a waterproof layer 104 is applied to the surfaces of the adjacent outer steel plates 101 and the surface of the connecting steel plate 103 on the side facing away from the inner wall of the foundation pit 5, so that the enclosure structure of the present invention can simultaneously perform support and waterproof functions, and can be used as "two walls in one." The waterproof layer 104 can be a rolled waterproof layer, a sprayed waterproof layer, a painted waterproof layer, etc. The specific material used to form the waterproof layer 104 is not limited here. It can be a commonly used waterproof material in the construction field as long as it can achieve a waterproof effect.

[0073] In an optional embodiment of the present invention, Figure 9 and Figure 10 As shown, the retaining structure for foundation pit support further includes steel purlins 6. The steel purlins 6 are formed to match the foundation pit 5. That is, when the foundation pit 5 is rectangular, a rectangular steel purlin 6 can be realized. When the retaining piles 1 are in the second state, the steel purlins 6 are arranged in the foundation pit 5 along the circumference of the foundation pit 5, and the steel purlins 6 are respectively connected to the inner support steel members 102 in each retaining pile 1. The steel purlins 6 support each retaining pile 1, further improving the stability of the support for the foundation pit 5, preventing the retaining piles 1 from tilting toward the inside of the foundation pit 5 due to the pressure of the soil, and improving the stability of each retaining pile 1.

[0074] Further, such as Figure 9 As shown, the retaining structure for foundation pit support also includes multiple support beams 7, and the two ends of the multiple support beams 7 are respectively welded to different edges of the steel purlin 6 to enhance the bearing capacity of the steel purlin 6 and further improve the stability of the foundation pit 5 support.

[0075] In an optional embodiment of the present invention, Figures 1 to 6 As shown, on the top edge and the bottom edge of the outer steel plate 101, one is provided with a convex positioning block 1013, and the other is provided with a concave positioning groove 1014; each retaining pile 1 is divided into multiple sections in the vertical direction, and the adjacent two sections of retaining piles 1 are connected by the positioning blocks 1013 and the positioning grooves 1014, so that multiple sections of retaining piles 1 can be vertically inserted in sections according to actual needs to meet the support requirements of the foundation pit 5.

[0076] Specifically, such as Figures 1 to 6As shown, a convex positioning block 1013 can be provided at the middle position of the top edge of the outer steel plate 101, and a concave positioning groove 1014 can be provided at the middle position of the bottom edge of the outer steel plate 101. The positioning block 1013 and the positioning groove 1014 can be plugged in and out. When multiple sections of retaining piles 1 are pressed into the soil in sections, after the lower section of retaining pile 1 is pressed into the soil to a preset depth, another retaining pile 1 is pressed above the retaining pile 1. The two vertically adjacent sections of retaining piles 1 are clamped together by the above-mentioned positioning block 1013 and the positioning groove 1014, and the position where the two vertically adjacent sections of retaining piles 1 contact each other is fully welded to ensure the stability of the connection of each section of retaining pile 1 in the vertical direction.

[0077] The characteristics and advantages of the retaining structure for foundation pit support of the present invention are:

[0078] 1. The retaining structure for foundation pit support, when the retaining pile 1 is in a state of being pressed downward into the soil, the cylindrical body and the inner supporting steel member 102 cooperate to achieve stable support for the soil, thereby achieving the effect of stable support for the foundation pit 5. The retaining pile 1 adopts an all-steel structure. Compared with the conventional manual bored pile construction process, the solution of the present invention does not need to wait for the strength of the retaining wall to be formed, reduces the conventional manual bored pile retaining wall maintenance time, speeds up the excavation progress, is safer, and is more convenient to construct.

[0079] 2. The retaining structure for foundation pit support, when the retaining pile 1 is in the foundation pit 5 excavation state after being pressed into the soil, the multiple outer steel plates 101 on the side away from the inner wall of the foundation pit 5 can be dismantled and recycled, and only one outer steel plate 101 close to the inner wall of the foundation pit 5 is retained, and at least part of the internal supporting steel parts 102 are in contact with or connected to the retained outer steel plate 101, which can not only meet the support requirements for the foundation pit 5, but also can be dismantled and part of the outer steel plates 101 can be recycled along with the excavation of the foundation pit 5, effectively reducing material waste and construction costs to achieve higher economic benefits, and the overall adoption of prefabricated construction is more energy-saving and environmentally friendly.

[0080] Implementation Method 2

[0081] like Figures 1 to 10 As shown, the present invention provides a construction method of a retaining structure, which is implemented by using the retaining structure for foundation pit support described above, and includes the following steps:

[0082] Step S1: determining a plurality of pile positions according to a preset foundation pit 5, each pile position corresponding to a retaining pile 1;

[0083] In step S1 , the site may be leveled in advance, and before the retaining piles 1 are pressed in, the specific positions of the plurality of piles may be determined according to the preset foundation pit 5 to achieve the purpose of accurate positioning and setting out.

[0084] Step S2: using at least three outer steel plates 101 to splice together to form a retaining pile 1 with a cylindrical main body, and multiple retaining piles 1 with a cylindrical main body can be spliced ​​together at one time;

[0085] Step S3: Pressing the retaining piles 1 into the plurality of pile positions respectively to form pile holes (i.e., the hollow area of ​​the retaining piles 1 having a cylindrical main body);

[0086] In an optional embodiment of the present invention, before step S3, soil at multiple pile positions is excavated for the retaining pile 1 to be pressed in, and a pile hole is formed in the cylindrical body of the retaining pile 1; or, after step S3, soil in the cylindrical body of the retaining pile 1 is excavated to form a pile hole.

[0087] Furthermore, in step S3, the retaining piles 1 can be pressed in with one hole in between. That is, skipping is performed to avoid interference between adjacent pile holes during construction, thus ensuring the quality and structural stability of the pile holes. For example, odd-numbered pile holes can be constructed first (e.g., retaining piles 1 can be pressed into pile positions 1, 3, and 5 first). After completion, after the filling material has initially solidified (approximately 24 hours), even-numbered pile holes can be constructed (e.g., retaining piles 1 can be pressed into pile positions 2, 4, and 6).

[0088] Furthermore, in step S3, for each pile position, multiple sections of retaining piles 1 are sequentially pressed in until the retaining pile 1 at the bottom is pressed down to the base of the pile position. After the retaining pile 1 at the bottom is pressed down to the corresponding pile position, a machine (such as a hydraulic static pile driver) can be used to press the retaining pile 1 downward into the soil, and then another section of retaining pile 1 is pressed in above it.

[0089] Furthermore, in step S3, when each section of the retaining pile 1 is pressed down, the top of the retaining pile 1 can be made 100 to 150 mm higher than the site plane, thereby playing the role of retaining soil, retaining water and positioning; then the soil within the range of the retaining pile 1 is excavated; in the actual construction process, if the downward pressure of the retaining pile 1 encounters greater resistance, the soil can be excavated first, and then the retaining pile 1 can be pressed down.

[0090] Furthermore, in step S3, after each section of the retaining pile 1 is pressed down into place, measuring tools such as a hanging line and a radius rod can be used to detect parameters such as the elevation of the pile hole bottom, the pile hole axis position, the cross-sectional dimensions of the pile hole, and the vertical flatness of the pile hole wall to ensure that the pile hole axis position, elevation, cross-sectional dimensions, etc. meet the pre-designed requirements; in addition, after each section of the retaining pile 1 is pressed down into place, the soil, residue at the bottom of the hole, and accumulated water in the cylindrical body formed by the retaining pile 1 should be cleared, and the concealed engineering acceptance should be carried out.

[0091] Step S4: Figure 7As shown, multiple inner support steel members 102 are lowered into corresponding pile holes, and at least a portion of the inner support steel members 102 is in contact with or connected to the outer steel plate 101 close to the inner wall of the foundation pit 5;

[0092] Furthermore, the outer steel plate 101 is a steel plate with an arc-shaped cross section, and the inner support steel member 102 is a vertically arranged steel section. In step S4, the inner support steel member 102 lowered into the pile hole must meet the following requirements: the flange plate of the steel section is parallel to the edge line of the foundation pit 5, and both ends of at least one flange plate of the steel section are in contact with or connected to the inner concave surface of the outer steel plate 101. The steel section supports and reinforces the outer steel plate 101, so that the steel section and the outer steel plate 101 form an integral structure, improving the stability of the support for the foundation pit 5. As the foundation pit 5 is excavated, multiple outer steel plates 101 away from the foundation pit 5 can be removed and recycled.

[0093] Specifically, in step S4, the processed steel section (steel section) can be hoisted into the pile hole of the retaining pile 1. In an optional embodiment of the present invention, the HW of the steel section can be, but is not limited to, 400×400×13×21 (i.e., the height H of the steel section is 400mm, the width B is 400mm, the web thickness t1 is 13mm, and the flange thickness t2 is 15mm). During the actual lowering of the steel section, "well"-shaped fixing brackets can be pre-installed at the upper and lower ends of the steel section. The fixing brackets cooperate with the inner wall of the pile hole to ensure that the steel section can be accurately lowered into the specified position in the pile hole. After the steel section is lowered into place, the fixing brackets can be removed.

[0094] Step S5: Figure 5 and Figure 6 As shown, fillers are injected into each pile hole to form the outer steel plate 101 and the inner supporting steel member 102 into a whole, thereby enhancing the integrity of the retaining pile 1 and ensuring that stress can be evenly transmitted at each position of the retaining pile 1;

[0095] Further, such as Figure 5 As shown, step S5 includes:

[0096] Step S501: injecting a first filler 2 into the base portion 8 of each pile hole and close to the bottom of the foundation pit 5; wherein the first filler 2 includes cement slurry, cement mortar or concrete;

[0097] Step 502: injecting a second filler 3 into each pile hole and above the first filler 2 to the pile top; wherein the second filler 3 includes plain soil, sand or solidified soil.

[0098] Further, such as Figure 6As shown, step S5 further includes injecting a third filler 4 into the small gap between the retained outer steel plate 101 and the inner supporting steel member 102. This not only ensures uniform stress transfer between the outer steel plate 101 and the inner supporting steel member 102, but also improves the integrity and pressure bearing capacity of the outer steel plate 101 and the inner supporting steel member 102, thereby ensuring the stability of the enclosure of the foundation pit 5. The third filler 4 comprises fine stone concrete with a strength grade of not less than C30.

[0099] Step S6: excavate the foundation pit 5 within the range enclosed by multiple retaining piles 1, and as the depth of the foundation pit 5 increases, remove part of the outer steel plates 101 (two or more outer steel plates 101 away from the inner wall of the foundation pit 5) within the excavated foundation pit 5; wherein, for each pile position, multiple outer steel plates 101 away from the inner wall of the foundation pit 5 are removed and recovered, and only one outer steel plate 101 close to the inner wall of the foundation pit 5 is retained.

[0100] Furthermore, in step S6, while removing and recovering the plurality of outer steel plates 101 on the side away from the inner wall of the foundation pit 5, part of the soil between the piles between two adjacent outer steel plates 101 is removed to provide space for the subsequent installation of the connecting steel plate 103.

[0101] Step S7: Figure 8 As shown, a connecting steel plate 103 is used to fully weld the side edges of two adjacent outer steel plates 101 in the circumferential direction of the foundation pit 5; in an optional embodiment of the present invention, the length of the connecting steel plate 103 may be but not limited to 1m, the width may be but not limited to 210mm, the thickness may be but not limited to 10mm, and the weld height between the connecting steel plate 103 and the outer steel plate 101 is not less than 10mm.

[0102] Step S8: A waterproof layer 104 is applied to the surfaces of the two adjacent outer steel plates 101 and the surface of the connecting steel plate 103 on the side facing away from the inner wall of the foundation pit 5. The waterproof layer 104 can be made of a roll waterproof layer, a spray waterproof layer, a brush waterproof layer, etc. The specific material of the waterproof layer 104 is not limited here. It can be any waterproof material commonly used in the construction field as long as it can achieve a waterproof effect.

[0103] Step S9: Figure 9 As shown, the steel purlin 6 is set in the foundation pit 5, and the steel purlin 6 is welded to the inner supporting steel member 102 in each retaining pile 1;

[0104] Step S10: Figure 9 As shown, multiple support beams 7 are provided, and the two ends of each support beam 7 are welded to different edges of the steel purlin 6;

[0105] Step S11: Figure 10As shown, when the construction of the main building reaches a certain stage, the cavities in the foundation pit fertilizer trough and the pile holes can be backfilled in sections, and the support beams 7 can be gradually dismantled and recovered.

[0106] The characteristics and advantages of the construction method of the enclosure structure of the present invention are:

[0107] 1. Compared with the conventional manual bored pile construction process, the construction method of the retaining structure of the present invention does not need to wait for the strength of the retaining wall to be formed, which reduces the maintenance time of the conventional manual bored pile retaining wall, speeds up the excavation progress, is safer, and is more convenient to construct.

[0108] 2. The construction method of the enclosure structure can dismantle and recycle multiple outer steel plates 101, which can not only meet the support requirements for the foundation pit 5, but also dismantle and recycle some outer steel plates 101 along with the excavation of the foundation pit 5, effectively reducing material waste and lowering construction costs to achieve higher economic benefits. Moreover, the overall assembly construction adopts more energy-saving and environmentally friendly.

[0109] 3. The construction method of the enclosure structure is to cover the surfaces of the two adjacent outer steel plates 101 and the surface of the connecting steel plate 103 on the side facing away from the inner wall of the foundation pit 5 with a waterproof layer 104, so that the enclosure structure of the present invention can simultaneously assume the functions of support and waterproofing, and can be used as "two walls in one".

[0110] 4. The construction method of the enclosure structure adopts prefabricated construction, which is more energy-saving and environmentally friendly, and is easy to construct. It can improve construction efficiency and reduce the workload of construction operations.

[0111] The construction method of the retaining structure of the present invention has the same characteristics and advantages as the retaining structure for foundation pit support described above, which will not be described in detail here.

[0112] It should be noted that, in the description of this application, the terms "first," "second," etc., are used solely for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, nor should they be understood to indicate or imply relative importance. Furthermore, in the description of this application, unless otherwise specified, "plurality" means two or more.

[0113] The above-mentioned various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0114] The above are only a few embodiments of the present invention. Although the embodiments disclosed in the present invention are as above, the contents are only for the purpose of facilitating understanding of the present invention and are not intended to limit the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A retaining structure for foundation pit support, characterized in that: The retaining structure for supporting the foundation pit includes a plurality of retaining piles located in the soil and supporting the inner wall of the foundation pit, wherein the plurality of retaining piles are arranged at intervals along the circumference of the foundation pit; The retaining pile has a first state and a second state, When the retaining pile is in the first state, the retaining pile includes a plurality of outer steel plates and an inner supporting steel member, the plurality of outer steel plates are spliced ​​together to form a cylindrical body of the retaining pile, the inner supporting steel member is located inside the cylindrical body, and at least a portion of the inner supporting steel member is in contact with or connected to the outer steel plates close to the inner wall of the foundation pit; When the retaining pile is in the second state, the retaining pile includes an outer steel plate and an inner supporting steel member. The outer steel plate is arranged close to the inner wall of the foundation pit and supports the inner wall of the foundation pit. The inner supporting steel member is in contact with or connected to the outer steel plate at least in part.

2. The retaining structure for foundation pit support according to claim 1, characterized in that: Insert blocks and slots are formed on two opposite side edges of the outer steel plate. When a plurality of the outer steel plates are spliced ​​together to form the cylindrical body, two circumferentially adjacent outer steel plates are engaged with each other through the insert blocks and the slots.

3. The retaining structure for foundation pit support according to claim 1, characterized in that: When the retaining piles are in the second state, a connecting steel plate is connected between the side edges of two adjacent outer steel plates along the circumference of the foundation pit.

4. The retaining structure for foundation pit support according to claim 3, characterized in that: The surfaces of the two adjacent outer steel plates and the surface of the connecting steel plate facing away from the inner wall of the foundation pit are covered with a waterproof layer.

5. The retaining structure for foundation pit support according to claim 1, characterized in that: On the top edge and bottom edge of the outer steel plate, one is provided with an outward convex positioning block, and the other is provided with an inward concave positioning groove; Each of the guardrail piles is divided into multiple sections in the vertical direction, and two adjacent sections of the guardrail piles are connected by the aligned positioning blocks and the positioning grooves.

6. A construction method of a retaining structure, which is implemented by using the retaining structure for foundation pit support according to any one of claims 1 to 5, characterized in that: The construction method of the enclosure structure comprises the following steps: Step S1: determining a plurality of pile positions according to a preset foundation pit, each of the pile positions corresponding to a retaining pile; Step S2: using outer steel plates to splice together to form a plurality of the retaining piles in a cylindrical body; Step S3: pressing the retaining piles into the plurality of pile positions respectively to form pile holes; wherein, for each pile position, multiple sections of the retaining piles are pressed in sequence until the retaining pile at the bottom is pressed down to the base position of the pile position; Step S4: lowering a plurality of inner supporting steel members into the corresponding pile holes, and making at least a portion of the inner supporting steel members contact or connect with the outer steel plate close to the inner wall of the foundation pit; Step S5: injecting filler into each of the pile holes to form the outer steel plate and the inner supporting steel member into an integral body; Step S6: excavating a foundation pit within the range enclosed by the plurality of retaining piles, and removing a portion of the outer steel plates within the excavated foundation pit as the depth of the foundation pit increases; For each pile position, a plurality of the outer steel plates away from the inner wall of the foundation pit are removed and recovered, and only one outer steel plate close to the inner wall of the foundation pit is retained.

7. The construction method of the enclosure structure according to claim 6, characterized in that: After step S6, the method further includes: Step S7: connecting the side edges of two adjacent outer steel plates in the circumferential direction of the foundation pit using a connecting steel plate; Step S8: A waterproof layer is provided on the surfaces of the two adjacent outer steel plates and the surface of the connecting steel plate facing away from the inner wall of the foundation pit.

8. The construction method of the enclosure structure according to claim 6, characterized in that: Before step S3, soil at a plurality of pile positions is excavated for the retaining piles to be pressed into, and pile holes are formed in the cylindrical bodies of the retaining piles; Alternatively, after step S3, the soil inside the cylindrical body of the retaining pile is excavated to form a pile hole.

9. The construction method of the enclosure structure according to claim 8, characterized in that: The outer steel plate is a steel plate with an arc-shaped cross section, and the inner supporting steel member is a vertically arranged steel section; In step S4, the inner supporting steel member lowered into the pile hole must satisfy the following requirement: the flange plate of the steel section is parallel to the edge line of the foundation pit.

10. The construction method of the enclosure structure according to claim 8, characterized in that: Step S5 The method comprises the following steps: step S501: injecting a first filler into the base portion of each pile hole and close to the bottom of the foundation pit; wherein the first filler comprises cement slurry, cement mortar or concrete; step S502: injecting a second filler into each pile hole and above the first filler; wherein the second filler comprises plain soil, sand or solidified soil; And / or, the step S5 includes injecting a third filler between the retained outer steel plate and the inner supporting steel member; wherein the third filler includes fine stone concrete.

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