Two-way servo system for foundation pit concrete support structure and its construction method

Abstract

This invention belongs to the field of foundation pit support technology and discloses a bidirectional servo system for foundation pit concrete support structure and its construction method. It can meet the deformation control requirements of ultra-long foundation pits and is used to support the retaining structure. The retaining structure is set on the sidewall of the foundation pit. The bidirectional servo system for foundation pit concrete support structure includes an active support structure and a servo structure. The active support structure includes walers and several longitudinal braces, all of which are connected to the retaining structure on opposite sides via walers. The servo structure is set in the active support structure. Multiple first servo jacks and multiple second servo jacks can provide bidirectional axial force to the retaining structure, effectively controlling the deformation of the retaining structure and flexibly adjusting the axial force to meet the deformation requirements of opposite sides of the retaining structure, coordinating the deformation on both sides of the retaining structure. Multiple relay servo jacks can reduce axial force loss.

Description

Technical Field

[0001] This invention relates to the field of foundation pit support technology, and in particular to a two-way servo system for foundation pit concrete support structure and its construction method. Background Technology

[0002] In the construction support structure of foundation pits, a retaining structure is set up on the side wall of the foundation pit, and the setting up of a support system is an important means to control the deformation of the retaining structure. In areas with high environmental requirements, a support servo structure (active support structure) is usually used to apply axial force to limit the deformation of the retaining structure. Commonly used servo support structures can be divided into two types according to materials: concrete support servo structures and steel support servo structures. The commonly used steel support servo structure is realized by connecting several steel pipes with bolts, which has poor load-bearing capacity. The concrete support servo structure is formed by setting up molds and pouring concrete in the foundation pit, and the concrete support servo structure has steel bars inside, which has a strong load-bearing capacity.

[0003] However, existing concrete support servo structures are generally unidirectional servo, that is, servo jacks are only installed on one side wall of the retaining structure near the foundation pit. This cannot guarantee the coordinated deformation of both sides of the retaining structure, and cannot avoid cracking of the retaining structure due to uncoordinated deformation, which can lead to water seepage and leakage. At the same time, when the foundation pit is large, the support length of the concrete support system is large, which will lead to a large loss of axial force transmitted by the concrete support servo structure, resulting in uneven axial force distribution and failure to fully utilize the bearing capacity.

[0004] Therefore, there is an urgent need for a device to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a bidirectional servo system for foundation pit concrete support structures, which can control the deformation coordination on both sides of the retaining structure, meet environmental requirements, and reduce the loss of support axial force.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A bidirectional servo system for supporting concrete structures in foundation pits, used to support the retaining structure, which is installed on the sidewall of the foundation pit, includes:

[0008] An active support structure, comprising a waler and a plurality of longitudinal braces, wherein the plurality of longitudinal braces are spaced apart in the horizontal direction and are all connected to the enclosure structure on opposite sides via the waler, and the plurality of longitudinal braces are perpendicular to the enclosure structure on the two sides to which they are connected.

[0009] A servo structure, disposed within the active support structure, includes multiple first servo jacks, multiple second servo jacks, and multiple relay servo jacks. The multiple first servo jacks are evenly spaced between the enclosure structure on one side and the waler on the corresponding side. The multiple second servo jacks are evenly spaced between the enclosure structure on the opposite side and the waler on the corresponding side. The first and second servo jacks provide support to the enclosure structure. Each longitudinal brace in the active support structure includes a first support and a second support. A relay servo jack is disposed between each pair of corresponding first and second supports. One end of the relay servo jack abuts against the first support, and the other end abuts against the second support. The relay servo jack reduces axial force loss.

[0010] Preferably, the first support and the second support are spaced apart along the same axis, and the first support and the second support have the same length.

[0011] Preferably, the active support structure further includes at least two suspension rods, some of which have one end connected to the waler on one side and the other end connected to the enclosure structure on the corresponding side, and some of which have one end connected to the waler on the opposite side and the other end connected to the enclosure structure on the corresponding side.

[0012] Preferably, the active support structure further includes two first steel plates, two second steel plates, and multiple relay steel plates. The first steel plates, second steel plates, and relay steel plates are all vertically arranged. One side of one of the first steel plates can be attached to one end of multiple first servo jacks, and the other side is connected to the enclosure structure on one side. Another first steel plate has one side attached to the other end of multiple first servo jacks, and the other side is connected to the waler on the corresponding side. Similarly, one side of one of the second steel plates can be attached to one end of multiple second servo jacks, and the other side is connected to the enclosure structure on the other side. Another second steel plate has one side attached to the other end of multiple second servo jacks, and the other side is connected to the waler on the corresponding side. Some of the relay steel plates have one side attached to one end of multiple relay servo jacks, and the other side is connected to the first support. The remaining relay steel plates have one side corresponding to the other end of each relay servo jack, and the other side corresponding to the second support.

[0013] Preferably, safety blocks are provided between two adjacent first servo jacks and between two adjacent second servo jacks, and the two ends of some of the safety blocks are respectively attached to two first steel plates, and the two ends of some of the safety blocks are respectively attached to two second steel plates.

[0014] Preferably, in each of the active support structures, the first support, the waler on one side, and the safety pier near the first support are integrally formed, and the second support, the waler on the other side, and the safety pier near the second support are integrally formed.

[0015] Preferably, the enclosure also includes a passive support structure, wherein the passive support structure and the active support structure are spaced apart along the height direction of the enclosure structure, the passive support structure includes the waler and a plurality of longitudinal braces spaced apart in the horizontal direction, the plurality of longitudinal braces are all connected to the enclosure structure on opposite sides through the waler, and the plurality of longitudinal braces are all perpendicular to the enclosure structure on the two sides to which they are connected.

[0016] Preferably, the walers on opposite sides of the passive support structure are respectively fixed to the enclosure structure on their corresponding sides.

[0017] Preferably, the passive support structure and the active support structure further include multiple connecting braces and multiple diagonal braces. The two ends of the multiple connecting braces in the active support structure and the passive support structure are respectively fixed between two adjacent longitudinal braces. One end of the multiple diagonal braces is fixed at the connection between the longitudinal brace and the connecting brace, and the other end is fixed to the waler.

[0018] Another objective of this invention is to provide a construction method for a bidirectional servo system for a foundation pit concrete support structure, which can control the deformation coordination on both sides of the retaining structure, meet environmental requirements, and reduce the loss of support axial force.

[0019] To achieve this objective, the present invention adopts the following technical solution:

[0020] The construction method for the bidirectional servo system of the foundation pit concrete support structure, applied to the aforementioned bidirectional servo system of the foundation pit concrete support structure, includes the following steps:

[0021] S1. Cast-in-place retaining structure;

[0022] S2. Excavate downwards between the newly poured retaining structure according to the design drawings to form a foundation pit;

[0023] S3. Cast walers and longitudinal braces for the passive support structure between the newly cast retaining structures.

[0024] Alternatively, cast the walers, first supports, and second supports of the active support structure between the newly cast retaining structures;

[0025] S4. Install the first servo jack, the second servo jack, and the relay servo jack in the active support structure. The first servo jack and the second servo jack are loaded and supported step by step, and the relay servo jack is loaded and supported.

[0026] Repeat steps S2 to S4 continuously until the foundation pit is excavated to the depth required by the design.

[0027] Beneficial Effects: This invention provides a bidirectional servo system for a foundation pit concrete support structure and its construction method, which can meet the deformation control requirements of ultra-long foundation pits. It is used to support the retaining structure, which is located on the sidewall of the foundation pit. The bidirectional servo system includes an active support structure and a servo structure. The active support structure includes walers and several longitudinal braces, which are spaced horizontally and connected to the retaining structures on opposite sides via walers. Each longitudinal brace is perpendicular to the retaining structures on its connected opposite sides. The servo structure is located within the active support structure and includes multiple first servo jacks, multiple second servo jacks, and multiple relay servo jacks. The multiple first servo jacks are evenly spaced. The first servo jack is positioned between the retaining structure on one side and the waler on the corresponding side. Multiple second servo jacks are evenly spaced between the retaining structure on one side and the waler on the other side. The first and second servo jacks can provide bidirectional axial force to the retaining structure, effectively controlling its deformation. The axial force can be flexibly adjusted according to the deformation control and environmental protection requirements at different locations of the retaining structure, respectively meeting the deformation requirements of the retaining structure on both sides and coordinating the deformation on both sides of the retaining structure. The longitudinal braces in the active support structure all include a first support, a second support, and a relay servo jack. One end of the relay servo jack abuts against the first support, and the other end abuts against the second support. The relay servo jack can reduce axial force loss. Attached Figure Description

[0028] Figure 1 This is a partial cross-section of the bidirectional servo system for the foundation pit concrete support structure provided in Embodiment 1 of the present invention. Figure 1 ;

[0029] Figure 2 This is a partial top view of the bidirectional servo system for the foundation pit concrete support structure provided in Embodiment 1 of the present invention;

[0030] Figure 3 This is a partial cross-section of the bidirectional servo system for the foundation pit concrete support structure provided in Embodiment 1 of the present invention. Figure 2 ;

[0031] Figure 4 This is a partial cross-section of the bidirectional servo system for the foundation pit concrete support structure provided in Embodiment 1 of the present invention. Figure 3 .

[0032] In the picture:

[0033] 100. Enclosure structure;

[0034] 1. Active support structure; 11. Waler; 12. Longitudinal brace; 121. First support; 122. Second support; 13. Connecting brace; 14. Diagonal brace; 15. Hanging rod; 16. First steel plate; 17. Second steel plate; 18. Intermediate steel plate; 19. First support plate; 1a. Second support plate; 1b. Intermediate support plate; 1c. Safety pier; 2. Passive support structure; 31. First servo jack; 32. Second servo jack; 33. Intermediate servo jack. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0039] Example 1

[0040] This embodiment provides a bidirectional servo system for supporting a foundation pit concrete support structure, used to support a retaining structure 100. The retaining structure 100 is set on the side wall of the foundation pit. Preferably, the retaining structure 100 is in the shape of a cuboid / cube, and in this embodiment, the retaining structure 100 is a vertically set underground continuous wall. The bidirectional servo system for supporting a foundation pit concrete support structure provided in this embodiment is set between two opposite side walls of the retaining structure 100. It can actively control the provided axial force and can effectively control the deformation of the retaining structure 100 by applying axial force in both directions. It can also flexibly adjust the axial force according to the deformation control and environmental protection requirements of different positions of the retaining structure 100 to meet the deformation requirements of opposite sides of the retaining structure 100, coordinate the deformation of both sides of the retaining structure 100, and compensate for axial force loss.

[0041] Specifically, such as Figure 1 As shown, the bidirectional servo system for the foundation pit concrete support structure provided in this embodiment includes an active support structure 1, a passive support structure 2, and a servo structure. In other feasible embodiments, only the active support structure 1 can be set to support the retaining structure 100. The passive support structure 2 can provide a certain axial force to the retaining structure 100, which is a passive control method. The servo structure is set in the active support structure 1. Compared with the passive support structure 2, the active support structure 1 can actively control the axial force applied to the retaining structure 100, and can also flexibly adjust the axial force according to the deformation of different positions of the retaining structure 100 and environmental protection requirements.

[0042] Furthermore, in this embodiment, multiple active support structures 1 are provided along the height direction of the retaining structure 100. Each active support structure 1 includes a waler 11 and several longitudinal supports 12. Preferably, in this embodiment, the retaining structure 100 is provided on the four side walls of the foundation pit and extends along the height direction of the foundation pit. The waler 11 is circumferentially fixed to the retaining structure on a horizontal plane. Several longitudinal supports 12 are connected to the retaining structures 100 on opposite sides through the waler 11. Several longitudinal supports 12 are all on the same horizontal plane. Specifically, several longitudinal supports 12 are spaced apart in the horizontal direction. That is, the two ends of the longitudinal supports 12 are respectively connected to the waler 11 on opposite sides, and thus can be connected to the retaining structures 100 on opposite sides. The cross-sectional shape of the waler 11 can be a regular rectangle / square or other irregular shapes, which are not specifically limited here.

[0043] Preferably, both the waler 11 and the longitudinal brace 12 are made of reinforced concrete, that is, they have a grid-like steel bar inside, and multiple steel bars are integrally formed by pouring concrete, which has a strong load-bearing capacity.

[0044] In this embodiment, a gap is reserved between the waler 11 in the active support structure 1 and the enclosure structure 100. For example, Figure 3 and Figure 4 As shown, the walers 11 on both sides and the enclosure structures 100 on both sides connected to them are connected by suspension rods 15. Specifically, one end of the suspension rod 15 is fixedly connected to the enclosure structure 100, and the other end is connected to the waler 11. In this embodiment, the two ends of the suspension rod 15 are respectively connected to the steel bars in the enclosure structure 100 and the steel bars in the waler 11 by welding, resulting in high connection strength. Preferably, the walers 11 on both sides are connected to the enclosure structure 100 on their corresponding side by multiple suspension rods 15 to improve the stability and reliability of the walers 11.

[0045] Further details can be found by referring to [link / reference]. Figure 1 In the active support structure 1, several longitudinal supports 12 are divided into first supports 121 and second supports 122. Specifically, the first supports 121 and the second supports 122 are arranged at intervals along the same axis. One end of the first support 121 is connected to the waler 11 on one side, and one end of the second support 122 is connected to the waler 11 on the opposite side. In this embodiment, the lengths of the first supports 121 and the second supports 122 are the same. In other embodiments, the length difference between the first supports 121 and the second supports 122 can be kept within a certain range.

[0046] In this embodiment, the servo structure is disposed within the active support structure 1. The servo structure includes multiple first servo jacks 31, multiple second servo jacks 32, and multiple relay servo jacks 33. The multiple first servo jacks 31 are evenly spaced between one side of the waler 11 and the corresponding side of the enclosure structure 100. One end of each first servo jack 31 can abut against one side of the enclosure structure 100, and the other end can abut against one end of a first support 121, providing support force to one side of the enclosure structure 100. The multiple second servo jacks 32 are evenly spaced between the opposite side of the waler 11 and the corresponding side of the enclosure structure 100, and each... One end of the second servo jack 32 can abut against the enclosure structure 100 on the other side, and the other end can abut against one end of the second support 122, to provide support force for the enclosure structure 100 on the other side; a relay servo jack 33 is provided between each pair of corresponding first supports 121 and second supports 122. Specifically, one end of the relay servo jack 33 can abut against the first support 121, and the other end can abut against the second support 122, to compensate for the loss of support force provided by the first servo jack 31 and the second servo jack 32 during the transmission process, to evenly distribute the support force at different positions of the enclosure structure 100, and to fully utilize the load-bearing capacity of the active support structure 1.

[0047] Preferably, the bidirectional servo system for the foundation pit concrete support structure in this embodiment also includes a control device. Multiple first servo jacks 31, multiple second servo jacks 32, and multiple relay servo jacks 33 are all controlled by the control device. The control device can flexibly adjust the supporting force provided by the first servo jacks 31, second servo jacks 32, and relay servo jacks 33 according to the deformation degree of different areas of the retaining structure 100 and environmental protection requirements, control the deformation of both sides of the retaining structure 100 to be coordinated, meet environmental requirements, reduce the loss of support axial force, and by setting the first servo jacks 31 and second servo jacks 32 between one side of the waler 11 and one side of the retaining structure 100, and between the opposite side of the waler 11 and the corresponding side of the retaining structure 100, the supporting force provided by the first servo jacks 31 and second servo jacks 32 can be evenly transmitted to each area through the two walers 11.

[0048] Optionally, in this embodiment, the distance between two adjacent first servo jacks 31 is 3m, and the distance between two adjacent second servo jacks 32 is also 3m. In other embodiments, these distances can be other values, which are not specifically limited here.

[0049] Preferably, the first servo jack 31, the second servo jack 32, and the relay servo jack 33 used in this embodiment are of the same model. Each of the first servo jack 31, the second servo jack 32, and the relay servo jack 33 is housed in a steel casing (not shown in the figure). The steel casing includes a base plate, two side plates, and a cover plate. The two side plates are disposed opposite each other on the base plate, and the cover plate is connected to the two side plates. A fixing part is provided on the base plate, and the shape of the fixing part matches the outer contour of the first servo jack 31 to prevent the first servo jack 31, the second servo jack 32, and the relay servo jack 33 from being used in malfunction. 3. During use, the servo jack 31 is displaced, and the front part of the first servo jack 31 can abut against the waler 11 on one side, and the rear part can abut against the enclosure structure 100 on the corresponding side. The front part of the second servo jack 32 can abut against the waler 11 on the opposite side, and the rear part can abut against the enclosure structure 100 on the corresponding side. The front part of the relay servo jack 33 can abut against the first support 121, and the rear part can abut against the second support 122. While protecting the first servo jack 31, the second servo jack 32 and the relay servo jack 33, it does not hinder their supporting function.

[0050] Furthermore, to support multiple first servo jacks 31 and multiple second servo jacks 32, the active support structure 1 provided in this embodiment also includes a first support plate 19 and a second support plate 1a. Specifically, the first support plate 19 is arranged along the length direction of one side of the waler 11. One end of the first support plate 19 is fixed to the enclosure structure 100 on the corresponding side, and the other end extends along the direction close to the waler 11 on the corresponding side. The steel sleeves fitted outside the first servo jacks 31 are all stably placed on the upper surface of the first support plate 19. The second support plate 1a is arranged along the length direction of the opposite side of the waler 11. One end of the second support plate 1a is fixed to the enclosure structure 100 on the other side, and the other end extends along the direction close to the waler 11 on the corresponding side. The steel sleeves fitted outside the second servo jacks 32 are all stably placed on the upper surface of the second support plate 1a. More preferably, in order to support multiple relay servo jacks 33, a relay plate 1b is provided at the end of the first support 121 near the second support 122. One end of the relay plate 1b is fixed to the first support 121, and the other end extends away from the first support 121. The steel sleeves fitted on the outside of the relay servo jacks 33 are stably placed on the upper surface of the corresponding relay plate 1b. Optionally, one end of the relay plate 1b can also be fixed to the end of the second support 122 near the first support 121. This is not specifically limited here.

[0051] The active support structure 1 in this embodiment also includes multiple safety blocks 1c. Specifically, some safety blocks 1c are arranged between two adjacent first servo jacks 31, and the waler 11 on the side adjacent to them is an integrally cast structure. One end of each safety block 1c is fixed to the corresponding side of the enclosure structure 100. The other part of the safety blocks 1c are arranged between two adjacent second servo jacks 32, and the waler 11 on the side adjacent to them is an integrally cast structure. One end of each safety block 1c is fixed to the corresponding side of the enclosure structure 100. When the first servo jack 31 and / or the second servo jack 32 malfunction or fail, the safety of the active support structure 1 can be guaranteed.

[0052] It should be noted that the first support 121, one side waler 11, and multiple safety piers 1c near the first support 121 in each active support structure 1 are integrally formed structures and are formed by concrete pouring. The second support 122, the opposite side waler 11, and multiple safety piers 1c near the second support 122 are also integrally formed structures and are formed by concrete pouring.

[0053] Preferably, such as Figure 3 and Figure 4 As shown, the active support structure 1 also includes two first steel plates 16, two second steel plates 17, and multiple relay steel plates 18. The first steel plates 16, second steel plates 17, and relay steel plates 18 are all vertically arranged. One side of one of the first steel plates 16 can be attached to one end of multiple first servo jacks 31, and the other side is connected to one side of the enclosure structure 100. One side of the other first steel plate 16 can be attached to the other end of multiple first servo jacks 31, and the other side is connected to the corresponding side of the waler 11. One side of one of the second steel plates 17 can be attached to one end of multiple second servo jacks 32, and the other side is connected to the other side of the enclosure structure 100. The enclosure structure 100 has one side of another second steel plate 17 that can be attached to the other end of multiple second servo jacks 32, and the other side is connected to the corresponding side of the waler 11; one side of a portion of the relay steel plate 18 can be attached to one end of multiple relay corner servo jacks, and the other side is connected to the first support 121; one side of the remaining relay steel plates 18 can be attached to the other end of each relay servo jack 33, and the other side is connected to the second support 122, so that the supporting force provided by the first servo jack 31, the second servo jack 32 and the relay servo jack 33 can be transmitted vertically and evenly, reducing losses.

[0054] Furthermore, such as Figure 2As shown, the active support structure 1 provided in this embodiment also includes multiple connecting braces 13 and multiple diagonal braces 14. Preferably, the multiple connecting braces 13 and multiple diagonal braces 14 are perpendicular to the enclosure structures 100 on opposite sides and are on the same horizontal plane as the multiple longitudinal braces 12. The two ends of the multiple connecting braces 13 are respectively fixed between two adjacent longitudinal braces 12 to improve the overall stability of the multiple longitudinal braces 12. One end of the multiple diagonal braces 14 is fixed at the connection between the longitudinal braces 12 and the connecting braces 13, and the other end is fixed to one side waler 11 / opposite side waler 11 to improve the stability of the active support structure 1.

[0055] In this embodiment, the connecting brace 13 and the diagonal brace 14 are made of reinforced concrete, with the internal steel bars forming an interwoven mesh, and are integrally cast with the two walers 11 and the longitudinal brace 12.

[0056] Furthermore, the bidirectional servo system for the foundation pit concrete support structure provided in this embodiment also includes a passive support structure 2. The passive support structure 2 and the active support structure 1 are arranged at intervals along the height direction of the retaining structure 100. In this embodiment, the active support structure 1 is set at the middle height of the retaining structure 100 to control the large deformation in the middle of the retaining structure 100 and coordinate the deformation of the retaining structure 100 at different heights. Specifically, when the passive support structure 2 and the active support structure 1 are used to support the retaining structure 100 at the same time, since the deformation of the retaining structure 100 is smaller closer to the ground, the uppermost support is usually set as the passive support structure 2. That is, the active support structure 1 is located below at least one passive support structure 2, which can not only meet the control requirements at this location, but also save the cost of setting up the servo structure.

[0057] Specifically, the passive support structure 2 also includes walers 11 and several longitudinal braces 12. The walers 11 on opposite sides are fixed to the enclosure structures 100 on opposite sides, and the several longitudinal braces 12 are all connected to the enclosure structures 100 on opposite sides through the walers 11. The several longitudinal braces 12 are all on the same horizontal plane. Specifically, the several longitudinal braces 12 are spaced apart in the horizontal direction. That is, the walers 11 on different sides are connected to the enclosure structure 100 on the corresponding side, and the two ends of the longitudinal braces 12 are connected to the walers 11 on opposite sides, and thus can be connected to the enclosure structures 100 on opposite sides. The cross-sectional shape of the walers 11 can be a regular rectangle / square, or other irregular shapes, which are not specifically limited here.

[0058] Furthermore, each waler 11 on each side of the passive support structure 2 is fixedly connected to the corresponding side enclosure structure 100. Specifically, the reinforcing bars in the walers 11 on opposite sides are welded to the enclosure structures 100 on opposite sides, resulting in a strong connection and improving the reliability and stability of the walers 11.

[0059] Example 2

[0060] This embodiment provides a construction method for a two-way servo system for foundation pit concrete support structures, applied to the aforementioned two-way servo system for foundation pit concrete support structures. The construction method for the two-way servo system for foundation pit concrete support structures includes the following steps:

[0061] S1, Cast the retaining structure 100;

[0062] S2. According to the design drawings, excavate downwards between the newly poured retaining structure 100 to form a foundation pit;

[0063] S3. Cast the walers 11 and longitudinal braces 12 of the passive support structure 2 between the newly cast retaining structure 100.

[0064] Alternatively, walers 11, first supports 121, and second supports 122 from the active support structure 1 can be poured between the newly poured retaining structures 100.

[0065] S4. Install and position the first servo jack 31, the second servo jack 32 and the relay servo jack 33 in the active support structure 1. The first servo jack 31 and the second servo jack 32 are loaded and supported step by step, and the relay servo jack 33 is loaded and supported.

[0066] Repeat steps S2 to S4 continuously until the foundation pit is excavated to the depth required by the design.

[0067] Preferably, four interconnected trenches are excavated downwards from the ground. Reinforcing steel structures are placed in these trenches, and then concrete is poured to form a retaining structure 100 of a certain height. The soil between the retaining structures 100 is then excavated to form an initial foundation pit. Further, a passive support structure 2 or an active support structure 1 is poured between the retaining structures 100. When the active support structure 1 is poured, a first servo jack 31, a second servo jack 32, and a relay servo jack 33 are installed and positioned. The first servo jack 31 and the second servo jack 32 provide progressive loading support, while the relay servo jack 33 provides loading support. Further, the excavation of the soil between the retaining structure 100 is continued to form a secondary foundation pit. A passive support structure 2 or an active support structure 1 is then poured below. Similarly, when the newly poured structure is an active support structure 1, the first servo jack 31, the second servo jack 32, and the relay servo jack 33 are installed and positioned. The first servo jack 31 and the second servo jack 32 provide progressive loading support, and the relay servo jack 33 provides loading support. The above process is repeated until the foundation pit is excavated to the depth required by the design. Preferably, the height of the retaining structure 100 / the height of the foundation pit is greater than 2.

[0068] Specifically, S1 includes:

[0069] S1.1. According to the design drawings, a trenching machine is used to form a trench, a steel reinforcement structure is placed in the trench, and concrete is poured to form an enclosure structure 100.

[0070] S2 includes:

[0071] S2.1. Excavate the foundation pit to a certain depth.

[0072] When casting the active support structure 1, S2 also includes:

[0073] S2.2, The first support plate 19 and the second support plate 1a are fixed to the enclosure structure 100 on opposite sides;

[0074] S2.3, One of the first steel plates 16 and one of the second steel plates 17 are fixed to the enclosure structure 100 on opposite sides.

[0075] Furthermore, S3 includes:

[0076] S3.1. Hoist and support the formwork for pouring the walers 11, several first supports 121, several connecting supports 13, several diagonal supports 14 and several safety piers 1c between the newly poured retaining structures 100.

[0077] S3.2. Hoist and support the formwork between the newly poured retaining structure 100 for pouring several second supports 122, several connecting supports 13, several diagonal supports 14 and several safety piers 1c.

[0078] S3.3 Connect one end of some of the hanging rods 15 to the enclosure structure 100 on one side and the other end to the waler 11 on the corresponding side. Connect one end of the remaining hanging rods 15 to the enclosure structure 100 on the opposite side and the other end to the waler 11 on the corresponding side.

[0079] S3.4 Install and position another first steel plate 16, another second steel plate 17, and relay steel plate 18.

[0080] That is, a template is erected to integrally form several first supports 121, several connecting supports 13, several diagonal supports 14, and several safety blocks 1c. One end of some of the hanging rods 15 is welded to the steel structure in the retaining structure 100 on one side, and the other end of some of the hanging rods 15 is welded to the steel structure in the waler 11 on the corresponding side to improve the connection strength. Furthermore, the end of the hanging rod 15 connected to the retaining structure 100 is higher than the first steel plate 16. The two first steel plates 16 and the two second steel plates 17 are all vertically opposite each other. The two first steel plates 16 and the two second steel plates 17 are at the same height. The first steel plate 16 is located above the first support plate 19, and the second steel plate 17 is located above the second support plate 1a. Several relay steel plates 18 are vertically set and are respectively set at the end of the first support 121 near the second support 122 and the end of the second support 122 near the first support 121. The several relay steel plates 18 are arranged one-to-one opposite each other.

[0081] When casting the passive support structure 2, S3 includes:

[0082] S3.1. Hoist and support the formwork for pouring the walers 11, several longitudinal supports 12, several connecting supports 13 and several diagonal supports 14 between the newly poured retaining structures 100;

[0083] Specifically, the reinforcing bars in the walers 11 on opposite sides are welded to the enclosure structure 100 on opposite sides.

[0084] Specifically, S4 includes:

[0085] S4.1 Install and position the first servo jack 31, the second servo jack 32 and the relay servo jack 33 in the active support structure 1.

[0086] The first servo jack 31 is placed in the reserved gap between one side of the waler 11 and the corresponding side of the enclosure structure 100. The second servo jack 32 is placed in the reserved gap between the opposite side of the waler 11 and the corresponding side of the enclosure structure 100. For example, in this embodiment, the distance between two adjacent first servo jacks 31 and two adjacent second servo jacks 32 is 3m. At the same time, each first servo jack 31 and each second servo jack 32 are respectively set between two adjacent safety blocks 1c. The two ends of the first servo jack 31 can respectively abut against two first steel plates 16, and the first servo jack 31... Each of the steel sleeves containing the first servo jack 31 is placed inside the steel sleeve box and is positioned on the upper surface of the first pallet 19. The two ends of the second servo jack 32 can respectively abut against two second steel plates 17, and the second servo jack 32 is placed inside the steel sleeve box and is positioned on the upper surface of the second pallet 1a. Each of the relay servo jack 33 can respectively abut against a pair of opposite relay steel plates 18, and the relay servo jack 33 is placed inside the steel sleeve box. The steel sleeve boxes containing the relay servo jack 33 are placed on the upper surface of multiple relay pallets 1b.

[0087] S4.2, Gradually load and support the first servo jack 31 and the second servo jack 32;

[0088] For example, in this embodiment, the western confining pressure of the servo area is calculated as 600 kN / m, and the eastern confining pressure of the servo area is calculated as 400 kN / m. Since the supporting force and quantity provided by the first servo jacks 31 and the second servo jacks 32 respectively set on the east and west sides should be balanced with the confining pressure on the corresponding side, and in this embodiment, the spacing between two adjacent first servo jacks 31 and the spacing between two adjacent second servo jacks 32 are both 3m, preferably, the spacing between two adjacent relay servo jacks 33 is also 3m, in the enclosure structure 10 After the size is determined, the maximum supporting force that each first servo jack 31 can provide is set to 120t, the maximum supporting force that each second servo jack 32 can provide is 180t, and the maximum supporting force that each relay servo jack 33 can provide is 10t. When the measured strength of the active support structure 1 reaches C30, the first servo jacks 31 and the second servo jacks 32 set on the east and west sides are simultaneously loaded to provide graded support. Specifically, it is divided into four levels of loading, and the supporting force is increased step by step through the control device. The loading increment of each level is set to 30t.

[0089] Preferably, the length of the first support 121 is set to be equal to the length of the second support 122.

[0090] S4.3, Loading support relay servo jack 33;

[0091] Specifically, after the first servo jack 31 and the second servo jack 32 are initially loaded, the control relay servo jack 33 provides a support force within ±10t to compensate for the loss of the support force provided by the first servo jack 31 and the second servo jack 32 during the transmission process, so as to evenly distribute the support force at different positions of the enclosure structure 100 and give full play to the load-bearing capacity of the active support structure 1.

[0092] During processes S4.2 and S4.3, as the first servo jack 31 and the second servo jack 32 apply supporting forces to the first steel plate 16 and the second steel plate 17 respectively, the gaps between the two first steel plates 16 and the two second steel plates 17 increase. If this results in gaps between the safety block 1c and the two first steel plates 16 and the two second steel plates 17, concrete grout is used to fill these gaps to ensure that the safety block 1c can be tightly abutted between the two first steel plates 16 and the two second steel plates 17.

[0093] Continue excavating the earthwork below, repeating steps S2 to S4 continuously, and construct the various support structures within the foundation pit until the foundation pit is excavated to the required design depth.

[0094] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A two-way servo system for supporting a concrete foundation pit, used to support a retaining structure (100) located on the sidewall of the foundation pit, characterized in that, include: An active support structure (1) includes a waler (11) and several longitudinal supports (12). The several longitudinal supports (12) are spaced apart in the horizontal direction and are all connected to the enclosure structure (100) on opposite sides through the waler (11). The several longitudinal supports (12) are all perpendicular to the enclosure structure (100) on the two sides to which they are connected. A servo structure is disposed in the active support structure (1) and includes a plurality of first servo jacks (31), a plurality of second servo jacks (32), and a plurality of relay servo jacks (33). The plurality of first servo jacks (31) are evenly spaced between the enclosure structure (100) on one side and the waler (11) on the corresponding side. The plurality of second servo jacks (32) are evenly spaced between the enclosure structure (100) on the opposite side and the waler (11) on the corresponding side. The first servo jacks (31) and the second servo jacks (33) are evenly spaced between the enclosure structure (100) on the opposite side and the waler (11) on the corresponding side. The servo jack (32) can provide support for the enclosure structure (100), and the longitudinal braces (12) in the active support structure (1) all include a first support (121) and a second support (122). A relay servo jack (33) is provided between each pair of the first support (121) and the second support (122). One end of the relay servo jack (33) abuts against the first support (121) and the other end abuts against the second support (122). The relay servo jack (33) can reduce axial force loss. It also includes a passive support structure (2), the passive support structure (2) and the active support structure (1) are spaced apart along the height direction of the enclosure structure (100), the passive support structure (2) includes the waler (11) and a plurality of longitudinal supports (12) spaced apart in the horizontal direction, the plurality of longitudinal supports (12) are all connected to the enclosure structure (100) on opposite sides through the waler (11), and the plurality of longitudinal supports (12) are all perpendicular to the enclosure structure (100) on the two sides to which they are connected; The passive support structure (2) and the active support structure (1) further include multiple connecting braces (13) and multiple diagonal braces (14). The two ends of the multiple connecting braces (13) in the active support structure (1) and the passive support structure (2) are respectively fixed between two adjacent longitudinal braces (12). One end of the multiple diagonal braces (14) is fixed at the connection between the longitudinal brace (12) and the connecting brace (13), and the other end is fixed to the waler (11).

2. The bidirectional servo system for the foundation pit concrete support structure according to claim 1, characterized in that, The first support (121) and the second support (122) are spaced apart along the same axis, and the first support (121) and the second support (122) have the same length.

3. The bidirectional servo system for foundation pit concrete support structure according to claim 1, characterized in that, The active support structure (1) further includes at least two suspension rods (15), one end of some of the suspension rods (15) is connected to the waler (11) on one side and the other end is connected to the enclosure structure (100) on the corresponding side, and one end of some of the suspension rods (15) is connected to the waler (11) on the opposite side and the other end is connected to the enclosure structure (100) on the corresponding side.

4. The bidirectional servo system for the foundation pit concrete support structure according to claim 1, characterized in that, The active support structure (1) further includes two first steel plates (16), two second steel plates (17), and multiple relay steel plates (18). The first steel plates (16), the second steel plates (17), and the relay steel plates (18) are all vertically arranged. One side of one of the first steel plates (16) can be attached to one end of multiple first servo jacks (31), and the other side is connected to the enclosure structure (100) on one side. Another first steel plate (16) can be attached to the other end of multiple first servo jacks (31) on one side, and the other side is connected to the waler (11) on the corresponding side. One side of one of the second steel plates (17) can be attached to one end of multiple first servo jacks (31). One side of one of the multiple second servo jacks (32) is able to fit against one end of the other side, and the other side is connected to the enclosure structure (100) on the other side. One side of another second steel plate (17) can fit against the other end of the multiple second servo jacks (32), and the other side is connected to the waler (11) on the corresponding side. One side of a portion of the relay steel plate (18) can fit against one end of the multiple relay servo jacks (33), and the other side is connected to the first support (121). One side of the remaining relay steel plates (18) can fit against the other end of each relay servo jack (33), and the other side is connected to the second support (122).

5. The bidirectional servo system for the foundation pit concrete support structure according to claim 4, characterized in that, Safety blocks (1c) are provided between two adjacent first servo jacks (31) and between two adjacent second servo jacks (32), and the two ends of some of the safety blocks (1c) are respectively attached to two first steel plates (16), and the two ends of some of the safety blocks (1c) are respectively attached to two second steel plates (17).

6. The bidirectional servo system for the concrete support structure of the foundation pit according to claim 5, characterized in that, The first support (121), the waler (11) on one side, and the safety pier (1c) near the first support (121) in each active support structure (1) are integrally formed, and the second support (122), the waler (11) on the other side, and the safety pier (1c) near the second support (122) are integrally formed.

7. The bidirectional servo system for the foundation pit concrete support structure according to claim 1, characterized in that, The walers (11) on opposite sides of the passive support structure (2) are respectively fixed to the enclosure structures (100) on their corresponding sides.

8. A construction method for a bidirectional servo system for a foundation pit concrete support structure, applicable to the bidirectional servo system for a foundation pit concrete support structure as described in any one of claims 1-7, characterized in that, Includes the following steps: S1, Cast-in-place retaining structure (100); S2. According to the design drawings, excavate downwards between the newly poured retaining structure (100) to form a foundation pit; S3. Cast the walers (11) and longitudinal braces (12) of the passive support structure (2) between the newly cast retaining structure (100). Alternatively, walers (11), first supports (121), and second supports (122) of the active support structure (1) can be poured between the newly poured retaining structure (100); S4. Install the first servo jack (31), the second servo jack (32) and the relay servo jack (33) in the active support structure (1). The first servo jack (31) and the second servo jack (32) are loaded and supported step by step, and the relay servo jack (33) is loaded and supported. Repeat steps S2 to S4 continuously until the foundation pit is excavated to the depth required by the design.

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