A self-servoing anchored steel sheet pile and its construction method

Abstract

This invention provides a self-servoing anchored steel sheet pile and its construction method. The self-servoing anchored steel sheet pile includes Larssen steel sheet piles at the lower level and H-beams at the higher level. A channel steel waler is installed at a height of -0.5 meters above the top of the lower Larssen steel sheet piles, forming a unified load-bearing structure and providing a tension end. A channel steel waler is also installed at the top of the higher H-beam piles, forming a unified whole and providing a tension end. A complete set of prestressed steel strand cables is connected to the channel steel waler of the lower Larssen steel sheet piles via high-precision anchors, forming a stable load-bearing system. The other end of the steel strand cables is connected to the channel steel waler of the higher H-beams, working synergistically to effectively restrain lateral deformation of the soil and ensure the stability of the foundation pit. To further improve the reliability of the system, prestress is applied to the steel strand cables in real time via a servo motor, servo controller, and servo feedback device, ensuring that the steel strand cables maintain a stable stress state throughout the construction process, providing a solid guarantee for the safe construction of the foundation pit.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and in particular relates to a self-servoing anchored steel sheet pile and its construction method, which is especially suitable for reinforcement operations of steel sheet pile support systems in soft soil foundations without internal support. Background Technology

[0002] With continuous urban renewal and rapid development of construction technology, the forms of foundation pits are becoming increasingly diverse. Construction safety, progress, and economic benefits have become the most critical considerations in foundation pit engineering. Traditional methods of reinforcement using cast-in-place piles with internal bracing are particularly inconvenient for foundation pits with ultra-long, ultra-deep, and small-section characteristics, such as utility tunnels and pipe galleries, due to their high cost and long construction period. Especially under soft soil foundation conditions, the axial force required for internal bracing to ensure the stability of the foundation pit is extremely large, which undoubtedly brings many limitations and challenges to the progress of earthwork excavation and foundation pit construction.

[0003] Therefore, selecting a simple, efficient, economical, and safe foundation pit support system has become a major challenge in current construction. As a crucial element of the support system, the control of the tension of prestressed steel strand cables is particularly critical. However, as construction progresses, the prestress in the prestressed steel strand cables continuously diminishes, undoubtedly increasing the construction difficulty of anchored cable foundation pit support systems.

[0004] For foundation pits such as utility tunnels and pipe galleries in soft soil foundations that are ultra-long, ultra-deep, and have small cross-sections, there is an urgent need for an innovative construction method. This method should involve reinforcement outside the excavation surface to effectively solve the problem of retaining soil during the foundation pit excavation process. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a self-servoing anchored steel sheet pile and its construction method, which can effectively constrain high soil masses during soft soil foundation excavation.

[0006] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0007] A self-servoing anchored steel sheet pile includes a low-level Larssen steel sheet pile with a channel steel waler installed at a top elevation of -0.5 meters; and a high-level H-beam with a channel steel waler installed at the top of the high-level H-beam. A complete set of steel strand cables is connected to the channel steel waler of the low-level Larssen steel sheet pile via anchors, and the other end of the steel strand cables is connected to the channel steel waler of the high-level H-beam. The three components work together to restrain the lateral deformation of the soil and ensure the stability of the foundation pit.

[0008] Furthermore, it also includes a servo control system for applying prestress to the steel strand cable. The servo control system includes a servo motor installed inside the hydraulic tensioning pump station, and a servo feedback device installed at the tail of the servo motor. Under the control of the servo controller, the application of prestress to the steel strand cable is controlled to ensure that the steel strand cable maintains a stable stress state during construction.

[0009] Furthermore, the channel steel waler of the lower Larssen sheet pile adopts a double-layer channel steel structure, while the channel steel waler of the higher H-beam adopts a single-layer channel steel structure.

[0010] Furthermore, in the channel steel waler of the lower Larssen sheet pile, one flange of the channel steel waler is fully welded to the lower Larssen sheet pile, and a connecting steel plate is fully welded between the other flange. A connecting steel plate is also fully welded to the joint between adjacent channel steel walers. A stiffening plate is also welded to the inside of the channel steel waler.

[0011] Furthermore, a steel triangular bracket is welded and fixed to the lower Larssen sheet pile. The steel triangular bracket is located below the lower channel steel waler and is used to provide support.

[0012] Furthermore, one end of the steel strand cable passes through the gap between the upper and lower channel steel walers and is fixed by an anchor. A steel pad is provided between the anchor and the flange of the channel steel waler. The gap between the upper and lower channel steel walers is filled with fine stone concrete, and the fine stone concrete is filled before the steel strand cable is tensioned.

[0013] A construction method for the above-mentioned self-servoing anchored steel sheet pile includes the following steps:

[0014] Step 1: Construction of low-level support piles;

[0015] The low-level support piles adopt low-level Larssen steel sheet piles, and channel steel walers are set at the top elevation of the low-level Larssen steel sheet piles at -0.5 meters to make the pile row form a unified whole for stress and provide tension end;

[0016] Step 2: Construction of high-altitude support piles;

[0017] The high-altitude support piles consist of two H-beams, with a channel steel waler installed on top of the high-altitude H-beam piles to form a unified whole, and a tension end is provided;

[0018] Step 3: Steel strand cable installation;

[0019] One end of the complete set of prestressed steel strand cables is connected to the channel steel waler of the Larssen steel sheet pile at the lower position through anchorage to form a stable force-bearing system. The other end of the steel strand cables is connected to the channel steel waler of the H-beam at the higher position. The three work together to effectively restrain the lateral deformation of the soil and ensure the stability of the foundation pit.

[0020] Step 4: Apply prestress to the steel strand cable in real time through servo motors, servo controllers and servo feedback devices to ensure that the steel strand cable maintains a stable stress state throughout the construction process.

[0021] The present invention has the following beneficial effects:

[0022] This invention, through unique technical design and process, ensures uniform stress distribution on the cantilever end of the sheet pile, thereby providing a stable and reliable support effect, making the entire support structure more robust and solid, and effectively controlling soil displacement within a minimal range. This not only strongly guarantees the safety of the cantilever end of the sheet pile during foundation pit excavation and significantly reduces construction risks, but also demonstrates excellent economic efficiency in improving material turnover, greatly reducing project costs, and providing an efficient, economical, and safe solution for construction in related fields.

[0023] The entire reinforcement system designed in this invention relies on the outer H-beams (or Larssen sheet piles) to hold the sheet pile walers, and then utilizes the rigidity of the sheet piles themselves. The two are superimposed to form a support system, which can reduce and avoid soil disturbance on the outside during the excavation of the foundation pit, ensure the stability of the soil, and occupy as little excavation face as possible. The construction is simple and convenient, and the double protection improves safety. The prestressed cables control stress and deformation, thereby reducing foundation pit deformation. Furthermore, the servo system automatically adjusts the stress of the prestressed steel strand cables to ensure that the prestress of the steel strand cables is not lost, thus ensuring the stability of the sheet piles. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall construction of the self-servoing anchored steel sheet pile described in this invention;

[0025] Figure 2 This is a schematic diagram of the elevation structure of the self-servoing anchored steel sheet pile described in this invention;

[0026] Figure 3 This is a schematic diagram of the cross-sectional structure of the self-servoing anchored steel sheet pile described in this invention;

[0027] Figure 4 This is a schematic diagram of the channel steel waler node of the low-lying Larssen sheet pile described in this invention;

[0028] Figure 5 This is a schematic diagram of the channel steel waler node of the low-lying Larssen sheet pile described in this invention;

[0029] Figure 6 This is a schematic diagram of the channel steel waler node of the low-lying Larssen sheet pile described in this invention;

[0030] Figure 7 This is a schematic diagram of the channel steel waler node of the low-lying Larssen sheet pile described in this invention;

[0031] In the diagram: 1-Channel steel waler; 2-Anchorage; 3-Larsen steel sheet pile at low elevation; 4-Steel strand cable; 5-Servo feedback device; 6-Servo controller; 7-Servo motor; 8-H-beam at high elevation; 9-Reinforcing steel triangular bracket; 10-Stiffening plate; 11-Connecting steel plate; 12-Steel pad plate; 13-Fine aggregate concrete; 14-Guardrail; 15-Waterstop; 16-Drainage ditch; Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0033] like Figure 1 , 2 As shown in Figure 3, the self-servoing anchored sheet pile of the present invention includes a channel steel waler 1, an anchor 2, a low-lying Larssen sheet pile 3, a steel strand cable 4, a servo feedback device 5, a servo controller 6, a servo motor 7, and an H-beam 8.

[0034] like Figure 1 , 2 As shown in Figure 3, the low-level support piles are Larssen sheet piles, namely, low-level Larssen sheet piles 3. A channel steel waler 1 is installed at the top of the low-level Larssen sheet piles 3 at an elevation of -0.5 meters, forming a unified whole for the pile group and providing a tension end. The high-level support piles are two H-beams, namely, high-level H-beams 8. A channel steel waler 1 is installed at the top of the high-level H-beams 8 to form a unified whole and provide a tension end.

[0035] like Figure 1 , 2 As shown in Figure 3, the complete set of prestressed steel strand cables 4 are connected to the channel steel waler 1 of the Larssen steel sheet pile 3 at the lower position through high-precision anchors 2, forming a stable force-bearing system; the other end of the steel strand cables 4 is connected to the channel steel waler 1 of the H-beam 8 at the higher position. The three work together to effectively restrain the lateral deformation of the soil and ensure the stability of the foundation pit.

[0036] like Figure 1 , 2 As shown in Figure 3, in order to further improve the reliability of the system, the present invention also includes a servo control system, including a servo motor 7 installed inside the hydraulic tensioning pump station, and a servo feedback device 5 installed at the tail of the servo motor 7. Under the control of the servo controller 6, the prestress applied to the steel strand cable 4 is controlled to ensure that the steel strand cable 4 maintains a stable stress state during the construction process, thereby providing a solid guarantee for the safe construction of the foundation pit.

[0037] Protective railings 14, water-stopping sills 15, and drainage ditches 16 are also installed on the soil between the low-lying Larssen sheet piles 3 and the high-lying H-beams 8.

[0038] like Figures 4 to 7As shown, the specific installation details of the channel steel waler 1 are as follows:

[0039] The channel steel waler 1 of the Larssen sheet pile 3 at the lower position adopts a double-layer channel steel structure, while the channel steel waler 1 of the H-beam 8 at the higher position adopts a single-layer channel steel structure.

[0040] In the channel steel waler 1 of the lower Larssen sheet pile 3, one flange of the channel steel waler 1 is fully welded to the lower Larssen sheet pile 3, and a connecting steel plate 11 is fully welded between the other flanges. The joint between adjacent channel steel walers 1 is also fully welded with connecting steel plates 11. A stiffening plate 10 is also welded and fixed inside the channel steel waler 1. A steel reinforcement triangular bracket 9 is also welded and fixed on the lower Larssen sheet pile 3. The steel reinforcement triangular bracket 9 is located below the lower channel steel waler 1 and is used to provide support. One end of the steel strand cable 4 passes through the gap between the upper and lower channel steel walers 1 and is fixed by the anchor 2. A steel pad 12 is set between the anchor 2 and the flange of the channel steel waler 1. Before the steel strand cable 4 is tensioned, the gap between the upper and lower channel steel walers 1 is filled with fine stone concrete 13 and the filling is ensured to be dense.

[0041] For the channel steel waler 1 of the high-level H-beam 8, the groove surface of the channel steel waler 1 is fully welded to the flange of the high-level H-beam 8. The other end of the steel strand cable 4 passes through the channel steel waler 1 and is fixed by the anchor 2. The steel strand cable 4 at this end is connected to the servo control system.

[0042] The construction method of the self-servoing anchored steel sheet pile of the present invention is as follows:

[0043] Step 1: Construction of low-level support piles;

[0044] The low-level support piles adopt the low-level Larssen steel sheet piles 3, and a channel steel waler 1 is set at the top elevation of the low-level Larssen steel sheet piles 3 at -0.5 meters, so that the pile row forms a unified whole for stress and provides a tension end.

[0045] Step 2: Construction of high-altitude support piles;

[0046] The high-altitude support piles consist of two H-beams (or Larssen sheet piles), and a channel steel waler 1 is installed on the top of the high-altitude H-beam 8 piles to form a unified whole and provide a tension end.

[0047] Step 3: Construction of steel strand cable 4;

[0048] One end of the complete set of prestressed steel strand cable 4 is connected to the channel steel waler 1 of the Larssen steel sheet pile 3 at the lower position through a high-precision anchor 2, forming a stable force-bearing system. The other end of the steel strand cable 4 is connected to the channel steel waler 1 of the H-beam 8 at the higher position. The three work together to effectively restrain the lateral deformation of the soil and ensure the stability of the foundation pit.

[0049] Step 4: Servo control system setup;

[0050] To further improve the reliability of the system, prestress is applied to the steel strand cable 4 in real time through the servo motor 7, servo controller 6 and servo feedback device 5 to ensure that the steel strand cable 4 maintains a stable stress state during construction, thereby providing a solid guarantee for the safe construction of the foundation pit.

[0051] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A self-servoing anchored steel sheet pile, characterized in that, The structure includes low-level Larssen sheet piles (3), with a channel steel waler (1) installed at a top elevation of -0.5 meters for the low-level Larssen sheet piles (3), and high-level H-beams (8), with a channel steel waler (1) installed at the top of the high-level H-beams (8); a complete set of steel strand cables (4) are connected to the channel steel waler (1) of the low-level Larssen sheet piles (3) through anchors (2), and the other end of the steel strand cables (4) is connected to the channel steel waler (1) of the high-level H-beams (8). The three work together to constrain the lateral deformation of the soil and ensure the stability of the foundation pit.

2. The self-servoing anchored sheet pile according to claim 1, characterized in that, It also includes a servo control system for applying prestress to the steel strand cable (4). The servo control system includes a servo motor (7) installed inside the hydraulic tensioning pump station and a servo feedback device (5) installed at the tail of the servo motor (7). Under the control of the servo controller (6), the prestress applied to the steel strand cable (4) is controlled to ensure that the steel strand cable (4) maintains a stable stress state during construction.

3. The self-servoing anchored sheet pile according to claim 1, characterized in that, The channel steel waler (1) of the low-level Larssen sheet pile (3) adopts a double-layer channel steel structure, while the channel steel waler (1) of the high-level H-beam (8) adopts a single-layer channel steel structure.

4. The self-servoing anchored sheet pile according to claim 3, characterized in that, In the channel steel waler (1) of the low-lying Larssen sheet pile (3), one side flange of the channel steel waler (1) is fully welded to the low-lying Larssen sheet pile (3), and a connecting steel plate (11) is fully welded between the other side flange. A connecting steel plate (11) is also fully welded to the joint between adjacent channel steel walers (1). A stiffening plate (10) is also welded to the inside of the channel steel waler (1).

5. The self-servoing anchored sheet pile according to claim 4, characterized in that, The lower Larssen sheet pile (3) is also welded and fixed with a steel triangular bracket (9), which is located below the lower channel steel waler (1) and is used to provide support.

6. The self-servoing anchored sheet pile according to claim 5, characterized in that, One end of the steel strand cable (4) passes through the gap between the upper and lower channel steel walers (1) and is fixed by the anchor (2). A steel pad (12) is provided between the anchor (2) and the flange of the channel steel waler (1). The gap between the upper and lower channel steel walers (1) is filled with fine stone concrete (13), and the fine stone concrete (13) is filled before the steel strand cable (4) is tensioned.

7. A construction method for the self-servoing anchored sheet pile as described in claim 2, characterized in that, The process includes the following: Step 1: Construction of low-level support piles; The low-level support piles adopt low-level Larssen steel sheet piles (3), and a channel steel waler (1) is set at the top elevation of the low-level Larssen steel sheet piles (3) at -0.5 meters, so that the piles form a unified whole and provide tension end; Step 2: Construction of high-altitude support piles; Two H-beams are used for the high-altitude support piles, and a channel steel waler (1) is set on the top of the high-altitude H-beam (8) pile to form a unified whole and provide a tension end; Step 3: Construction of steel strand cable (4); One end of the complete set of prestressed steel strand cable (4) is connected to the channel steel waler (1) of the low Larssen steel sheet pile (3) through the anchor (2) to form a stable force system. The other end of the steel strand cable (4) is connected to the channel steel waler (1) of the high H-beam (8). The three work together to effectively constrain the lateral deformation of the soil and ensure the stability of the foundation pit. Step 4: Apply prestress to the steel strand cable (4) in real time through the servo motor (7), servo controller (6) and servo feedback device (5) to ensure that the steel strand cable (4) maintains a stable stress state during construction.

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