Slipform blade and method for applying precompression strain to cast-in-place concrete of well wall

Abstract

The present invention discloses a slipform blade foot and method for applying pre-compression strain to cast-in-situ concrete of a shaft wall. The slipform blade foot is an annular structure, comprising a plurality of blade foot block structures connected end to end, each blade foot block structure comprising: a blade foot block body, a vertical displacement generating device, a displacement sensor and a limit plate. The vertical displacement generating device is arranged between a lower plate and an arc panel, and is used to drive the displacement of the arc panel in the vertical direction; the displacement sensor is arranged on the telescopic end of the vertical displacement generating device; the limit plate is an I-shaped structure, and is used to limit the maximum displacement distance of the arc panel. The present invention is suitable for vertical shaft walls constructed using a top-down, short excavation and short masonry process. It can extrude cast-in-situ concrete by applying upward displacement to the arc panel, quickly and accurately apply pre-compression strain to the cast-in-situ concrete of the shaft wall, improve the density of the cast-in-situ concrete in the shaft wall section and the joint cast-in-situ concrete, and significantly improve the overall water sealing performance of the shaft wall.

Description

Technical Field

[0001] The invention relates to the technical field of mine shaft and tunnel construction engineering, in particular to a sliding form blade and a method for applying pre-compression strain to cast-in-situ concrete of a shaft wall. Background Art

[0002] For the vertical shaft wall constructed by top-down, short excavation and short masonry technology, including but not limited to the existing single-layer shaft wall structure and outer shaft wall structure, such as Figure 1 and Figure 2 As shown in Figure 1, the traditional sliding blade foot is generally made of 4 to 8 steel structure blade foot blocks connected by bolts or welded, such as Figure 3 As shown, each blade foot block is composed of various components such as an upper plate, a curved plate, an outer plate, a lower plate, reinforcement ribs, a limit block, an inner support rib, and an inner plate that are bolted or welded to each other, and the components cannot move relative to each other. The blade foot bears the weight of the slipform and the cast-in-place concrete in this section at the same time. Due to problems such as temperature stress of the cast-in-place concrete of the well wall, sagging of the slipform blade foot, poor concrete working performance or insufficient vibration, water-conducting cracks and joint water-conducting cracks often appear in the well wall concrete of certain sections after hardening. Water-conducting cracks and joint water-conducting cracks in the sections seriously weaken the water-sealing performance of the well wall, and in severe cases may induce water inrush or flooding accidents in the wellbore.

[0003] Applying precompressive strain to the cast-in-place concrete during shaft wall construction is an effective way to reduce water-conducting cracks in the cast-in-place concrete. The most common method is to use micro-expansive concrete, which generates a micro-expansive strain in the cast-in-place concrete, typically around 300 microstrains. The constrained expansion of the concrete generates compressive strain. However, the amount of precompressive strain generated by this technique depends on the amount of expansive agent added and the degree of concrete restraint. It cannot be manually adjusted or controlled during the concrete hardening process. Therefore, this technique is a passive and difficult-to-accurate method for applying precompressive strain to cast-in-place concrete.

[0004] In order to achieve the purpose of active control of prestressing strain, there is also a method of applying prestressing strain to concrete. Specifically, during the pouring of concrete on the well wall, tools are used to manually tighten the nuts at the bottom of each section of vertical steel bars. The nuts support the joint steel plate to produce an upward displacement, thereby applying prestressing strain to the cast-in-place concrete on the well wall.

[0005] However, this method requires the use of nuts at the bottom of the steel bars and joint steel plates to apply pre-compression strain to the cast-in-place concrete of the shaft wall, and is only applicable to the "Single-layer Shaft Wall with Joint Plate and Its Construction Method ZL200610088128.3". Moreover, since the tension of a single steel bar is only 0.2kN~0.52kN, the tension of the steel bar that can be generated by this method is very small, that is, the pre-compression strain that can be applied to the concrete is very small, and the value of the pre-compression strain cannot be accurately adjusted or controlled. In addition, it takes at least 2 hours to manually tighten the nuts at the bottom of each section of vertical steel bar, which is time-consuming and labor-intensive. In short, it is difficult for the above methods to quickly and accurately apply pre-compression strain to the cast-in-place concrete of the shaft wall. Summary of the Invention

[0006] The purpose of the present invention is to provide a sliding form blade and method for applying pre-compression strain to the cast-in-situ concrete of the well wall. The sliding form blade and method are suitable for the well wall constructed from top to bottom and with short excavation and short masonry technology. The sliding form blade and method can quickly and accurately apply pre-compression strain to the cast-in-situ concrete of the well wall, thereby improving the density of the cast-in-situ concrete in the well wall section and the cast-in-situ concrete in the joints, avoiding the occurrence of water-conducting cracks in the section and water-conducting cracks in the joints of the well wall concrete after hardening, and ultimately significantly improving the overall water-sealing performance of the well wall.

[0007] The technical solution of the present invention is:

[0008] A slipform blade foot for applying pre-compressive strain to cast-in-situ concrete on a well wall is an annular structure, comprising a plurality of blade foot block structures connected end to end, each of the blade foot block structures comprising: a blade foot block body, comprising: a lower plate; an outer plate, vertically arranged at one end of the lower plate; a blade foot block connecting plate, one end of which is connected to the other end of the lower plate; an upper plate, one end of which is connected to the other end of the blade foot block connecting plate, and a hole groove is provided on the upper plate; an arc panel, one end of which slides on the outer plate through its lower edge structure, and the other end overlaps with the upper plate; a vertical displacement generating device, arranged between the lower plate and the arc panel, the fixed end being fixedly connected to the lower plate, and the telescopic end being fixedly connected to the arc panel, for driving the displacement of the arc panel in the vertical direction; a displacement sensor, arranged on the telescopic end of the vertical displacement generating device, for real-time monitoring of the vertical displacement value applied by the vertical displacement generating device; real-time monitoring of the vertical displacement h applied by the vertical displacement generating device to ensure that h is not greater than L. When the curved panel's rigidity is sufficiently high, the overall upward vertical displacement of the curved panel is equal to the vertical displacement h applied by the vertical displacement generating device. The limit plate has an I-shaped structure, with two horizontal surfaces and one vertical surface. One end of one horizontal surface of the limit plate is fixedly connected to one end of the curved panel, while the vertical surface extends through the slot in the upper plate and is slidably connected thereto. The other horizontal surface is located below the upper plate, and the dimensions of both horizontal surfaces are larger than the slot. The maximum upward displacement of the curved panel is equal to the length L that the limit plate extends beyond the upper plate.

[0009] Furthermore, the arc panel is a steel structure, which ensures that the arc panel will not be deformed during the entire process of the slipform blade applying pre-compression strain to the cast-in-place concrete of the shaft wall.

[0010] Furthermore, the vertical displacement generating device is a hydraulically driven vertical displacement generating device. The hydraulic system can achieve high-precision control of displacement through a servo valve, which is more suitable for scenarios such as concrete strain monitoring that require strict alignment or graded loading.

[0011] Furthermore, the cross-section of the lower edge structure is L-shaped, one end of the arc panel is connected to the outside of the right-angle position of the lower edge structure, the longer right-angle side of the lower edge structure is slidingly connected to the inner plate surface of the outer plate, and the shorter right-angle side is overlapped with the end of the outer plate away from the lower plate.

[0012] A method for applying pre-compression strain to cast-in-situ concrete on a well wall, using the above-mentioned slipform blade for construction, comprises the following steps:

[0013] S1 high excavation construction, the height of the excavated section is equal to Finally, lower the slipform blade and align it; tie the steel bars, install the formwork, and pour the concrete;

[0014] S11 determines the height of cast-in-place concrete , the preload strain value to be applied ; The vertical displacement h that needs to be applied to the arc panel is determined by the segment height. and the required preload strain value Determine, and h≤L, L is the length of the limit plate beyond the lower edge of the upper plate;

[0015] During the S12 concrete pouring process, Evenly distributed within the range There are three vertical concrete strain gauge measuring points, and the measured strain values ​​are: , ， …, ; Among them, 2≤ ≤8, segment height = Excavation height = Cast-in-place concrete height; Section height The average vertical strain of concrete in the range Where, is the number of the measuring point, For the The vertical concrete strain value measured at each measuring point; each concrete vertical strain gauge measuring point measures the vertical concrete strain through a concrete strain gauge. The concrete strain gauge can be tied to the vertical steel bar. The test cable of the concrete strain gauge is led out and connected to the test instrument to measure the strain reading. This is an existing technical means and will not be elaborated here.

[0016] S2 is the precompression strain value applied as needed from the initial setting to the final setting of the concrete. , operate the vertical displacement generating device to drive the arc panel to apply an upward vertical displacement h. Before demolding, the arc panel maintains the vertical displacement value unchanged.

[0017] During the pre-compression strain process of S21, the control program is used to monitor and calculate in real time The vertical displacement h applied to the arc panel by computer feedback and vertical displacement generating device is used to make The value remains at the target value .

[0018] Furthermore, during the application of pre-compression strain, The value remains at the target value The control method includes the following steps:

[0019] S211 Initialization: Determine the target preload strain value to be applied ; Reset the vertical displacement h applied by the vertical displacement generating device to the arc panel to zero; set the allowable error .

[0020] S212 real-time measurement and calculation: The concrete vertical strain value is read in real time by the concrete strain gauge embedded in the concrete , and calculate the segment height The average vertical strain of concrete in the range .

[0021] if , then the vertical displacement generating device is driven to increase the vertical displacement h of the arc panel.

[0022] if , then the vertical displacement generating device is driven to reduce the vertical displacement h of the arc panel.

[0023] if Within the allowable error range, the current vertical displacement h of the arc panel is maintained.

[0024] S213 When the system reaches a stable state, and Always stay at target value When it is within the allowable error range, stop adjusting the vertical displacement generating device.

[0025] Furthermore, the control method further includes:

[0026] Limit the maximum displacement of the vertical displacement generating device, h≤L.

[0027] when ≤500 microstrain, emergency stop of vertical displacement generating device to avoid crushing cast-in-place concrete.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] During the concrete pouring process of the vertical shaft wall constructed by the top-down, short excavation and short masonry process, the present invention controls the vertical displacement generating device to drive the vertical displacement of the arc panel, applies upward displacement to the arc panel to squeeze the cast-in-situ concrete, and generates pre-compression strain inside the cast-in-situ concrete, which can improve the density of the cast-in-situ concrete in the shaft wall section and the joint cast-in-situ concrete, avoid the occurrence of water-conducting cracks in the section and water-conducting cracks in the joint of the shaft wall concrete after hardening, and ultimately significantly improve the overall water-sealing performance of the shaft wall.

[0030] In the process of applying pressure and prestressing strain, the present invention reads the vertical strain of different sections of concrete in real time through the concrete strain gauge, calculates the average vertical strain, compares the average vertical strain with the vertical strain of the target value, and operates the vertical displacement generating device to drive the arc panel so that the average vertical strain is always kept within the allowable error range of the vertical strain of the target value, so as to ensure the concrete prestressing strain value. The strain range is 300 microstrain to 500 microstrain, which reduces the risk of concrete cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a perspective view of the traditional blade foot structure.

[0032] Figure 2 This is a top view of the traditional blade foot structure.

[0033] Figure 3 This is a perspective view of the traditional blade foot block structure.

[0034] Figure 4 This is a top view of the traditional blade foot block structure.

[0035] Figure 5 It is a cross-sectional view of the blade foot block structure schematic diagram of the present invention.

[0036] Among them, 1. Arc panel, 2. Lower plate, 3. Outer plate, 4. Upper plate, 5. Blade foot block connecting plate, 6. Vertical displacement generating device, 7. Displacement sensor, 8. Limit plate. DETAILED DESCRIPTION

[0037] The following combination Figures 1 to 5, a detailed description of the specific embodiments of the present invention is provided. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limiting the present invention.

[0038] It should be noted that the circuit connections involved in the present invention all adopt conventional circuit connection methods and do not involve any innovation.

[0039] Example

[0040] A slipform blade foot for applying pre-compression strain to cast-in-situ concrete on a well wall has the same blade foot block connection structure as the traditional blade foot structure, both of which are annular structures and include multiple blade foot block structures connected end to end. Adjacent blade foot block structures are connected by bolts. In this embodiment, each blade foot block structure of a slipform blade foot for applying pre-compression strain to cast-in-situ concrete on a well wall includes: a blade foot block body, a vertical displacement generating device 6, a displacement sensor 7 and a limit plate 8, as shown in FIG. Figure 5As shown, the blade foot block main body includes: a lower plate 2, an outer plate 3, a blade foot block connecting plate 5, an upper plate 4 and an arc panel 1, the outer plate 3 is vertically arranged at one end of the lower plate 2; one end of the blade foot block connecting plate 5 is connected to the other end of the lower plate 2; one end of the upper plate 4 is connected to the other end of the blade foot block connecting plate 5, and a hole groove is provided on the upper plate 4; one end of the arc panel 1 slides on the outer plate 3 through its lower edge structure, and the other end is overlapped with the upper plate 4; the cross-section of the lower edge structure is L-shaped, one end of the arc panel 1 is connected to the outside of the right-angle position of the lower edge structure, the longer right-angle side of the lower edge structure is slidably connected to the inner plate surface of the outer plate 3, and the shorter right-angle side is overlapped with the end of the outer plate 3 away from the lower plate 2, and cooperates with the limit plate 8 to keep the arc panel 1 sliding in the vertical direction; the vertical displacement generating device 6 is provided on the lower plate 2 and Between the arc panels 1, the fixed end is fixedly connected to the lower plate 2, and the telescopic end is fixedly connected to the arc panel 1, which is used to drive the displacement of the arc panel 1 in the vertical direction. The vertical displacement generating device 6 is selected from one of the pneumatic drive, hydraulic drive and electric drive that can be controlled by an external controller. This embodiment uses a hydraulically driven vertical displacement generating device 6. Since the hydraulic system can achieve high-precision control of the displacement through the servo valve, it is more suitable for scenarios such as concrete strain monitoring that require strict alignment or graded loading; the displacement sensor 7 is arranged on the telescopic end of the vertical displacement generating device 6, which is used to monitor the vertical displacement value applied by the vertical displacement generating device 6 in real time; when the stiffness of the arc panel 1 is large enough, the overall upward vertical displacement of the arc panel 1 is equal to the vertical displacement h applied by the vertical displacement generating device 6. Controlling the vertical displacement generating device 6 drives the vertical displacement of the curved panel 1, applying an upward displacement to the curved panel 1 to squeeze the cast-in-place concrete, generating pre-compression strain within the cast-in-place concrete. The limiting plate 8 is an I-shaped structure with two horizontal surfaces and one vertical surface. One end of one horizontal surface of the limiting plate 8 is fixedly connected to one end of the curved panel 1, and the vertical surface passes through the hole slot on the upper plate 4 and is slidably connected to the hole slot. The other horizontal surface is located below the upper plate 4. The dimensions of both horizontal surfaces are larger than the dimensions of the hole slot. The displacement sensor 7 monitors the vertical displacement h applied by the vertical displacement generating device 6 in real time to ensure that h is not greater than L, that is, the maximum upward displacement of the curved panel 1 is equal to the length L of the limiting plate 8 extending beyond the upper plate 4.

[0041] The vertical displacement generating device 6 is controlled by the hydraulic system to drive the arc panel 1 to achieve precise vertical displacement, thereby more accurately applying upward displacement to the arc panel 1 to squeeze the cast-in-place concrete. Pre-compression strain will be generated inside the cast-in-place concrete, which can improve the density of the cast-in-place concrete in the well wall section and the joint cast-in-place concrete, avoid the appearance of water-conducting cracks in the section and water-conducting cracks in the joints of the well wall concrete after hardening, and ultimately significantly improve the overall water-sealing performance of the well wall.

[0042] In order to ensure that the arc panel 1 will not be deformed during the entire process of the slip form blade applying pre-compression strain to the cast-in-place concrete of the shaft wall, the arc panel 1 in this embodiment is a steel structure.

[0043] A method for applying pre-compression strain to cast-in-situ concrete on a well wall, using the above-mentioned slipform blade for construction, comprises the following steps:

[0044] S1 high excavation construction, the height of the excavated section is equal to Finally, lower the slipform blade and align it; tie the steel bars, install the formwork, and pour the concrete;

[0045] S11 determines the height of cast-in-place concrete , the preload strain value to be applied ; The vertical displacement h needs to be applied to the curved panel 1, and the vertical displacement h is determined by the segment height and the required preload strain value Determine, and h≤L, L is the length of the limit plate 8 beyond the lower edge of the upper plate 4;

[0046] During the S12 concrete pouring process, Evenly distributed within the range There are three vertical concrete strain gauge measuring points, and the measured strain values ​​are: , ， …, ; Among them, 2≤ ≤8, segment height = Excavation height = Cast-in-place concrete height; Section height The average vertical strain of concrete in the range Where, is the number of the measuring point, For the The vertical concrete strain value measured at each measuring point;

[0047] In this embodiment, Take 2m~4m, the preload strain value to be applied 300 microstrain ~ 500 microstrain; the vertical displacement h≈ , and h≤L, L is the length of the limiting plate 8 exceeding the lower edge of the upper plate 4.

[0048] If there are too few measuring points, such as 1 to 2 measuring points, it may be difficult to accurately reflect the true shape of the strain distribution. If there are too many measuring points, such as 5 to 8 measuring points, it will not only increase the layout cost and data processing complexity, but also have limited improvement in accuracy. Three concrete vertical strain gauge measuring points are evenly distributed within the range, and the vertical heights of the three concrete vertical strain gauge measuring points are 、 and The vertical concrete strain values ​​measured at the three measuring points are 、 and , which can effectively capture the nonlinear strain gradient of concrete caused by its own weight, shrinkage or external loads, such as compression at the bottom and tension at the top, The average vertical strain of concrete in the range Each concrete vertical strain gauge measuring point measures the vertical strain of the concrete through a concrete strain gauge. The concrete strain gauge can be tied to the vertical steel bar. The test cable of the concrete strain gauge is led out and connected to the test instrument to measure the strain reading. This is an existing technical means and will not be elaborated here.

[0049] S2 is the time between the initial setting and final setting of the concrete, which is usually 2 to 6 hours after the concrete is poured. The preload strain value is applied as needed. , operate the vertical displacement generating device 6 to drive the arc panel 1 to apply an upward vertical displacement h. Before demolding, the arc panel 1 maintains the vertical displacement value unchanged.

[0050] During the pre-compression strain process of S21, the control program is used to monitor and calculate in real time The vertical displacement h applied to the curved panel 1 by computer feedback and the vertical displacement generating device 6 is so that The value remains at the target value .

[0051] The vertical strain at different heights of the concrete is read in real time by the concrete strain gauge, and the average vertical strain is calculated. The average vertical strain is compared with the vertical strain of the target value, and the vertical displacement generating device 6 is operated to drive the arc panel 1 so that the average vertical strain is always kept within the allowable error range of the vertical strain of the target value, so as to ensure the concrete precompression strain value. The strain range is 300 microstrain to 500 microstrain, which reduces the risk of concrete cracking.

[0052] During the pre-compression strain application process of S21, The value remains at the target value The control method includes the following steps:

[0053] S211 Initialization: Determine the target preload strain value to be applied . Set the vertical displacement h applied by the vertical displacement generating device 6 to the arc panel 1 to zero. Set the allowable error .

[0054] S212 real-time measurement and calculation: The vertical strain of concrete is read in real time by the concrete strain gauge embedded in the concrete 、 and , and calculate the segment height The average vertical strain of concrete in the range .

[0055] if , then the vertical displacement generating device 6 is driven to increase the vertical displacement h of the curved panel 1;

[0056] if , then the vertical displacement generating device 6 is driven to reduce the vertical displacement h of the curved panel 1;

[0057] if If the error is within the allowable range, the current vertical displacement h of the arc panel 1 is maintained;

[0058] S213 When the system reaches a stable state, and Always stay at target value When it is within the allowable error range, stop adjusting the vertical displacement generating device 6.

[0059] In some embodiments, the control method further includes:

[0060] The maximum displacement of the vertical displacement generating device 6 is limited, h≤L.

[0061] when ≤500 microstrain, emergency stop of the vertical displacement generating device 6 to avoid crushing the cast-in-place concrete.

[0062] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A slipform blade for applying pre-compression strain to cast-in-situ concrete on a well wall, having an annular structure and comprising a plurality of blade blocks connected end to end, characterized in that: Each of the blade foot block structures comprises: The blade foot block body comprises: a lower plate (2); an outer plate (3) vertically arranged at one end of the lower plate (2); a blade foot block connecting plate (5) with one end connected to the other end of the lower plate (2); an upper plate (4) with one end connected to the other end of the blade foot block connecting plate (5), and a hole groove is provided on the upper plate (4); an arc plate (1) with one end slidably arranged on the outer plate (3) through its lower edge structure, and the other end overlapped with the upper plate (4); A vertical displacement generating device (6) is arranged between the lower plate (2) and the arc panel (1), with a fixed end fixedly connected to the lower plate (2) and a telescopic end fixedly connected to the arc panel (1), and is used to drive the displacement of the arc panel (1) in the vertical direction; A displacement sensor (7) is provided on the telescopic end of the vertical displacement generating device (6) and is used to monitor the vertical displacement value applied by the vertical displacement generating device (6) in real time; The limiting plate (8) has an I-shaped structure and has two horizontal surfaces and one vertical surface. One end of one horizontal surface of the limiting plate (8) is fixedly connected to one end of the arc plate (1). The vertical surface passes through the hole groove on the upper plate (4) and is slidably connected to the hole groove. The other horizontal surface is located below the upper plate (4). The dimensions of the two horizontal surfaces are both larger than the dimensions of the hole groove.

2. The slipform blade for applying pre-compression strain to cast-in-situ concrete on a well wall according to claim 1, characterized in that: The curved panel (1) is a steel structural member.

3. The slipform blade for applying pre-compression strain to cast-in-situ concrete on a well wall according to claim 1, characterized in that: The vertical displacement generating device (6) is driven by one of pneumatic drive, hydraulic drive and electric drive which can be controlled by an external controller.

4. The slipform blade for applying pre-compression strain to cast-in-situ concrete on a well wall according to claim 1, characterized in that: The cross-section of the lower edge structure is L-shaped, one end of the arc panel (1) is connected to the outside of the right-angle position of the lower edge structure, one right-angle side of the lower edge structure is slidably connected to the inner plate surface of the outer plate (3), and the other right-angle side is overlapped with the end of the outer plate (3) away from the lower plate (2).

5. A method for applying pre-compression strain to cast-in-situ concrete on a well wall, characterized in that: The construction using the sliding form blade foot according to any one of claims 1 to 4 comprises the following steps: S1 high excavation construction, the height of the excavated section is equal to Finally, lower the slipform blade and align it; tie the steel bars, install the formwork, and pour the concrete; S11 determines the height of cast-in-place concrete , the preload strain value to be applied ; The vertical displacement h required to be applied to the arc panel (1) is determined by the height of the segment and the required preload strain value Determine, and h≤L, L is the length of the limit plate (8) beyond the lower edge of the upper plate (4); During the S12 concrete pouring process, Evenly distributed within the range There are three vertical concrete strain gauge measuring points, and the measured strain values ​​are: , ， …, ; Among them, 2≤ ≤8, segment height = Excavation height = Cast-in-place concrete height, section height The average vertical strain of concrete in the range , where is the number of the measuring point, For the The vertical concrete strain value measured at each measuring point; S2 is the precompression strain value applied as needed from the initial setting to the final setting of the concrete. , operating the vertical displacement generating device (6) to drive the arc panel (1) to apply an upward vertical displacement h, and before demoulding, the arc panel (1) maintains the vertical displacement value unchanged; During the pre-compression strain process of S21, the control program is used to monitor and calculate in real time The vertical displacement h applied to the arc panel (1) by computer feedback and the vertical displacement generating device (6) is such that The value remains at the target value .

6. A method for applying pre-compression strain to cast-in-situ concrete on a well wall according to claim 5, characterized in that: During the application of pre-compression strain, S21 The value remains at the target value The control method includes the following steps: S211 initialization: Determine the target preload strain value to be applied ; Resetting the vertical displacement h applied by the vertical displacement generating device (6) to the arc panel (1) to zero; Setting tolerance ; S212 real-time measurement and calculation: Real-time reading of concrete vertical strain values , and calculate the segment height The average vertical strain of concrete in the range ; if , then the vertical displacement generating device (6) is driven to increase the vertical displacement h of the arc panel (1); if , then the vertical displacement generating device (6) is driven to reduce the vertical displacement h of the arc panel (1); if If the error is within the allowable range, the current vertical displacement h of the arc panel (1) is maintained; S213 When the system reaches a stable state, and Always stay at target value When the error is within the allowable range, the adjustment of the vertical displacement generating device (6) is stopped.

7. A method for applying pre-compression strain to cast-in-situ concrete on a well wall according to claim 6, characterized in that: The control method further includes: Limiting the maximum displacement of the vertical displacement generating device (6), h≤L; when ≤500 microstrain, the vertical displacement generating device (6) is stopped urgently to avoid crushing the cast-in-place concrete.

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