A method for maintaining the pressure of a subway top foundation excavation construction

Abstract

The application discloses a method for maintaining the holding pressure in the excavation construction of the subway top foundation, and the steps are as follows: S1, installing a pressure sensor on the subway top; S2, installing a first pressure increasing mechanism and a second pressure increasing mechanism on a working frame; S3, detecting the pressure value by the pressure sensor and controlling the first pressure increasing mechanism to increase the pressure; S4, controlling the excavation mechanism to excavate the foundation at the second pressure increasing mechanism to form a groove; S5, controlling the second pressure increasing mechanism to extend into the groove and increase the pressure and controlling the first pressure increasing mechanism to release the pressure; S6, controlling the excavation mechanism to excavate the foundation at the first pressure increasing mechanism to form a groove; S7, controlling the first pressure increasing mechanism to extend into the groove and increase the pressure of the foundation and controlling the second pressure increasing mechanism to release the pressure; and S8, repeating S3-S7 until the excavation is completed. The application ensures that the holding pressure of the subway top is within a predetermined range, avoids the change of the strength of the subway top, and causes the deformation and collapse accidents. The application is suitable for the technical field of the foundation construction of the subway top.

Description

Technical Field

[0001] This invention belongs to the technical field of subway top foundation construction, specifically, it relates to a method for maintaining clamping pressure during subway top foundation excavation construction. Background Technology

[0002] Currently, during the excavation of the subway roof foundation, the reduction in earthwork gradually decreases the clamping pressure on the subway roof. If this reduced clamping pressure is not replenished, the subway roof is highly susceptible to deformation, which can affect its strength, shorten its lifespan, and in more serious cases, cause a collapse. However, there is currently no effective method to overcome this problem and ensure that the clamping pressure on the subway roof remains within a predetermined range during foundation excavation. Summary of the Invention

[0003] This invention provides a method for maintaining clamping pressure during the excavation of the subway top foundation. This method ensures that the clamping pressure of the subway top is within a predetermined range during the excavation process, effectively preventing changes in the strength of the subway top and thus avoiding accidents such as deformation and collapse.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for maintaining clamping pressure during the excavation of the foundation at the top of a subway station includes the following steps: S1. Anchor multiple fixed columns on the ground, avoiding the top of the subway, and install multiple pressure sensors below the excavation site on the top of the subway. S2. The working frame is fixed to the ground by the aforementioned multiple fixed columns. A first pressurizing mechanism and a second pressurizing mechanism are installed on the working frame, and the first pressurizing mechanism and the second pressurizing mechanism alternately pressurize the excavated foundation. S3. The pressure value detected by the pressure sensor is used to control the first pressurization mechanism to pressurize the excavated foundation so that the pressure value detected by the pressure sensor reaches the predetermined value. S4. Control the excavation mechanism to move. The excavation foundation at the second pressurization mechanism, which has not pressurized the excavated foundation, is excavated by the excavation mechanism, so that a groove is formed below the second pressurization mechanism. S5. Remove the excavated soil, then control the second pressurizing mechanism to extend its lower end into the groove and pressurize the excavated foundation, and control the first pressurizing mechanism to release the pressure on the excavated foundation. S6. Then, control the excavation mechanism to excavate the foundation at the first pressurization mechanism, so that a groove is formed below the first pressurization mechanism. S7. Remove the excavated soil, then control the first pressurizing mechanism to extend its lower end into the corresponding groove and pressurize the excavated foundation. Control the second pressurizing mechanism to release the pressure on the excavated foundation. S8. Repeat steps S3-S7 until the foundation of the subway top is excavated to the predetermined depth.

[0005] Furthermore, in step S2, the working frame is connected to each fixed column through multiple stepping travel mechanisms, and the fixed columns are set vertically. As the first pressurizing mechanism and the second pressurizing mechanism alternately pressurize the excavated foundation, and as the excavation mechanism gradually excavates downward, the stepping travel mechanism drives the working frame to move downward along the fixed columns. When the stepping travel mechanism and the working frame are disturbed by the soil around the fixed columns, the soil around the fixed columns needs to be cleared manually.

[0006] Furthermore, the stepping travel mechanism includes a vertical hydraulic cylinder connected to the work frame. A first hydraulic clamp and a second hydraulic clamp are respectively connected to the cylinder body and cylinder rod of the vertical hydraulic cylinder, and both the first hydraulic clamp and the second hydraulic clamp are fitted onto the corresponding fixed column.

[0007] Furthermore, the first pressurizing mechanism includes two first connecting longitudinal beams arranged side by side, each of the first connecting longitudinal beams being connected to the working frame via multiple first hydraulic cylinders, and a first pressurizing component being spaced apart between the two first connecting longitudinal beams along the length direction of the first connecting longitudinal beams, the first pressurizing component being connected to the two first connecting longitudinal beams via a first connecting frame.

[0008] Furthermore, the second pressurizing mechanism includes two second connecting longitudinal beams arranged side by side. Each second connecting longitudinal beam is connected to the working frame through multiple second hydraulic cylinders. A second pressurizing component is arranged at intervals along the length direction of the two second connecting longitudinal beams. The second pressurizing component is connected to the two second connecting longitudinal beams through a second connecting frame. The second pressurizing component and the first pressurizing component are alternately arranged on the excavated foundation surface.

[0009] Furthermore, the first pressure member and the second pressure member have the same structure, and the first connecting frame and the second connecting frame have the same structure; the first connecting frame includes two insert rods arranged opposite to each other on both sides of the first pressure member, the upper end of each insert rod is inserted into the first support rod, and a rigid spring is fitted on the outside of the insert rod, the two ends of the rigid spring are fixed to the first pressure member and the first support rod respectively, and the upper end of the first support rod is fixedly connected to the corresponding first connecting longitudinal beam.

[0010] Furthermore, the first pressure member is a plate-like structure or an assembled beam-like structure.

[0011] Furthermore, the lower part of the first pressure member has an arc-shaped structure, and the arc-shaped structure protrudes downward.

[0012] Furthermore, the excavation mechanism includes a drive unit that is driven by a first pressurizing mechanism or a second pressurizing mechanism. The drive unit is driven by a rotary drilling unit, which rotary digs and excavates the protruding part of the foundation to form a groove on the protruding part.

[0013] Furthermore, the drive unit includes a drive motor or a hydraulic motor; a guide seat is connected to the lower end of the drive unit, the guide seat is slidably connected to a slide rail detachably mounted on the first or second pressurizing mechanism, a rack is detachably mounted on the first or second pressurizing mechanism, and a traveling gear that meshes with the rack is coaxially mounted on the output shaft of the drive unit; the rotary drilling unit includes a drive rod with helical blades, and a drill bit is mounted on the lower end of the drive rod; the transmission unit includes a first bevel gear and a second bevel gear disposed in a transmission box and meshing with each other, the first bevel gear is mounted on the output shaft of the drive unit, and the second bevel gear is mounted on the upper end of the drive rod.

[0014] The present invention, by employing the aforementioned structure, achieves a technological advancement compared to existing technologies in the following ways: During the excavation of the foundation at the top of the subway, the reduction in earthwork leads to a decrease in the pressure value detected by the pressure sensor. Therefore, it is necessary to control the alternating operation of the first and second pressurizing mechanisms to pressurize the excavated foundation, thus replenishing the pressure on the subway top. Because the first and second pressurizing mechanisms alternately pressurize the excavated foundation, the earthwork below the first or second pressurizing mechanism that is not pressurizing the excavated foundation can be excavated. After excavation, a groove is formed in this area, thus... The first or second pressurizing mechanism corresponding to the groove extends into the groove and pressurizes the excavated foundation. The first or second pressurizing mechanism, which previously pressurized the excavated foundation, is gradually released. Then, the excavation mechanism excavates the soil below, making it also a groove. This process is repeated, so that the subway top is subjected to a predetermined pressure while the excavated foundation is gradually excavated downwards. In summary, this invention ensures that the pressure on the subway top is within a predetermined range during the excavation of the subway top foundation, effectively preventing changes in the strength of the subway top that could lead to deformation, collapse, or other accidents. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the buckling pressure holding device according to an embodiment of the present invention; Figure 2 for Figure 1 Enlarged view of the structure at part A in the middle; Figure 3 This is a side view of the buckle pressure retaining device according to an embodiment of the present invention; Figure 4 This is a partial structural schematic diagram of the buckling pressure retaining device according to an embodiment of the present invention; Figure 5 This is a partial structural diagram of the connection between the first pressurizing component and the first connecting frame in the first pressurizing mechanism of the present invention. Figure 6 for Figure 5 Structural side view; Figure 7 This is a partial structural diagram showing the connection between another first pressurizing component and the first connecting frame in the first pressurizing mechanism of this embodiment of the invention; Figure 8 for Figure 7 Structural side view; Figure 9 This is a schematic diagram of the transmission connection between the excavation mechanism and the first pressurization mechanism in an embodiment of the present invention; Figure 10 for Figure 9 The structural front view.

[0017] Components labeled: 100-Working frame, 200-Fixed column, 300-Stepping travel mechanism, 301-Vertical hydraulic cylinder, 302-Cylinder rod, 303-First hydraulic clamp, 304-Second hydraulic clamp, 400-First pressurizing mechanism, 401-First connecting longitudinal beam, 402-First hydraulic cylinder, 403-First support rod, 404-First connecting rod, 405-First pressurizing component, 406-Insertion rod, 407-Hard spring, 408-Slide rail, 409-Rack, 500-Second pressurizing mechanism, 501 - Second connecting longitudinal beam, 502- Second hydraulic cylinder, 503- Second support rod, 504- Second connecting rod, 505- Second pressure component, 600- Excavating foundation, 601- Boss part, 602- Groove, 700- Excavation mechanism, 701- Transmission part, 7011- Transmission box, 7012- First bevel gear, 7013- Second bevel gear, 702- Rotary drilling part, 7021- Drive rod, 7022- Spiral blade, 7023- Drill bit, 703- Travel gear, 704- Guide seat, 705- Output shaft. Implementation

[0018] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0019] This invention discloses a method for maintaining clamping pressure during the excavation and construction of the subway roof foundation, such as... Figure 1-10As shown, it achieves the purpose of supplementing the clamping pressure on the top of the subway through a clamping pressure holding device. The clamping pressure holding device includes a working frame 100, a first pressurizing mechanism 400 and a second pressurizing mechanism 500.

[0020] The buckling force holding method in this invention includes the following steps: S1. Anchor multiple fixed columns 200 on the ground, avoiding the top of the subway. These fixed columns 200 are all vertically installed. Since the fixed columns 200 avoid the top of the subway, they will not affect the top of the subway during the stress process. The present invention installs multiple pressure sensors below the excavation site on the top of the subway. The pressure sensors are arranged below the deepest excavation site, and are generally installed on the load-bearing beams on the top of the subway. S2. The working frame 100 is fixed to the ground by the aforementioned multiple fixed columns 200. The first pressurizing mechanism 400 and the second pressurizing mechanism 500 are installed on the working frame 100, and the first pressurizing mechanism 400 and the second pressurizing mechanism 500 operate alternately to achieve the purpose of pressurizing the excavated foundation 600. S3. By using the pressure value detected by the pressure sensor, the first pressurizing mechanism 400 is controlled to pressurize the excavated foundation 600 so that the pressure value detected by the pressure sensor reaches the predetermined value. S4. Control the excavation mechanism 700 to move. The excavation foundation 600 at the second pressurization mechanism 500, which does not pressurize the excavation foundation 600, is excavated by the excavation mechanism 700, so that a groove 602 is formed below the second pressurization mechanism 500. S5. Remove the excavated soil, then control the second pressurizing mechanism 500 to extend its lower end into the groove 602 and pressurize the excavated foundation 600, and control the first pressurizing mechanism 400 to release the pressure on the excavated foundation 600. S6. Then, control the excavation mechanism 700 to excavate the foundation 600 at the first pressurization mechanism 400, so that a groove 602 is formed below the first pressurization mechanism 400. S7. Remove the excavated soil, then control the first pressurizing mechanism 400 to extend its lower end into the corresponding groove 602 and pressurize the excavated foundation 600. Control the second pressurizing mechanism 500 to release the pressure on the excavated foundation 600. S8. Repeat steps S3-S7 until the foundation of the subway top is excavated to the predetermined depth.

[0021] The working principle and advantages of this invention are as follows: When excavating the foundation of the subway top, the pressure value detected by the pressure sensor decreases due to the reduction in earthwork. Therefore, it is necessary to control the alternating operation of the first pressurizing mechanism 400 and the second pressurizing mechanism 500 to pressurize the excavated foundation 600, thus replenishing the pressure on the subway top. Since the first pressurizing mechanism 400 and the second pressurizing mechanism 500 alternately pressurize the excavated foundation 600, the earthwork below the first pressurizing mechanism 400 or the second pressurizing mechanism 500 that is not pressurizing the excavated foundation 600 can be excavated. After excavation, a groove 602 is formed at this location, allowing the corresponding area to... The first pressurizing mechanism 400 or the second pressurizing mechanism 500 extends into the groove 602 and pressurizes the excavated foundation 600. The pressurizing mechanism 500 or the first pressurizing mechanism 400 is gradually released from the excavated foundation 600. Then, the excavation mechanism 700 excavates the soil below it, making it also a groove 602. This process is repeated, so that the subway top is subjected to a predetermined pressure while the excavated foundation 600 is gradually excavated downwards. In summary, the present invention ensures that the pressure on the subway top is within a predetermined range during the excavation of the subway top foundation, effectively preventing changes in the strength of the subway top that could lead to deformation, collapse, or other accidents.

[0022] In a preferred embodiment of the present invention, as excavation progresses, the working frame 100, the first pressurizing mechanism 400, and the second pressurizing mechanism 500 need to be lowered as a whole so that the first pressurizing mechanism 400 and the second pressurizing mechanism 500 can effectively pressurize the excavated foundation 600. Specifically, as Figure 1-2As shown, in step S2, the work frame 100 is connected to each fixed column 200 via multiple stepping travel mechanisms 300, and the fixed columns 200 are vertically arranged. As the first pressurizing mechanism 400 and the second pressurizing mechanism 500 alternately pressurize the excavated foundation 600, and as the excavation mechanism 700 gradually excavates downwards, the stepping travel mechanisms 300 drive the work frame 100 to move downwards along the fixed columns 200. When the stepping travel mechanisms 300 and the work frame 100 are disturbed by the soil around the fixed columns 200, the soil around the fixed columns 200 needs to be manually removed. The specific structure of the stepping travel mechanism 300 in this embodiment is as follows: the stepping travel mechanism 300 includes a vertical hydraulic cylinder 301, which is mounted on the work frame 100. A first hydraulic clamp 303 and a second hydraulic clamp 304 are respectively connected to the cylinder body and cylinder rod 302 of the vertical hydraulic cylinder 301. Moreover, the first hydraulic clamp 303 and the second hydraulic clamp 304 are both fitted outside the corresponding fixed column 200. The working principle of this embodiment is as follows: When the working frame 100 needs to be lowered, the second hydraulic clamp 304 is controlled to clamp the fixed column 200, the first hydraulic clamp 303 releases the clamp on the fixed column 200, the vertical hydraulic cylinder 301 is activated, thereby causing the working frame 100 to move downward. Then, the first hydraulic clamp 303 is controlled to clamp the fixed column 200 again, the second hydraulic clamp 304 releases the clamp on the fixed column 200, and the vertical hydraulic cylinder 301 is activated again to achieve the purpose of step-down movement. At the same time, during the downward movement of the working frame 100, the pressure of the first pressurizing mechanism 400 or the second pressurizing mechanism 500 on the excavated foundation 600 is adjusted so that the clamping pressure borne by the top of the subway is kept within a predetermined range.

[0023] As a preferred embodiment of the present invention, such as Figure 1 , 3As shown, the first pressurizing mechanism 400 includes two first connecting longitudinal beams 401 arranged side by side. Each first connecting longitudinal beam 401 is connected to the working frame 100 through multiple first hydraulic cylinders 402. Multiple first pressurizing components 405 are connected between the two first connecting longitudinal beams 401. These first pressurizing components 405 are spaced apart along the length direction of the first connecting longitudinal beams 401, and each first pressurizing component 405 is connected to the two first connecting longitudinal beams 401 through a first connecting frame. The second pressurizing mechanism 500 includes two second connecting longitudinal beams 501 arranged side by side. Each second connecting longitudinal beam 501 is connected to the working frame 100 through multiple second hydraulic cylinders 502. Multiple second pressurizing components 505 are connected between the two second connecting longitudinal beams 501. These second pressurizing components 505 are spaced apart along the length direction of the second connecting longitudinal beams 501. Each second pressurizing component 505 is connected to the two second connecting longitudinal beams 501 through a second connecting frame. The second pressurizing components 505 and the first pressurizing component 405 are alternately arranged on the surface of the excavated foundation 600. In this embodiment, the components of the first pressurizing mechanism 400 and the second pressurizing mechanism 500 that pressurize the excavated foundation 600 are the first pressurizing component 405 and the second pressurizing component 505. Multiple first hydraulic cylinders 402 synchronously drive the first connecting longitudinal beam 401 downwards, achieving pressurization of the excavated foundation 600 by all the first pressurizing components 405. Similarly, multiple second hydraulic cylinders 502 synchronously drive the second connecting longitudinal beam 501 downwards, achieving pressurization of the excavated foundation 600 by all the second pressurizing components 505. Furthermore, the first pressurizing component 405 and the second pressurizing component 505 in this embodiment have the same structure, as do the first connecting frame and the second connecting frame. The first connecting frame includes two first support rods 403 arranged opposite each other on both sides of the first pressurizing component 405. These two first support rods 403 are connected by multiple first connecting rods 404, thereby improving the stability of the connection between the first support rods 403 and the first pressurizing component 405. The second connecting frame includes two second support rods 503 that are arranged opposite to each other on both sides of the second pressure member 505. These two second support rods 503 are connected by multiple second connecting rods 504, thereby improving the stability of the connection between the second support rods 503 and the second pressure member 505.

[0024] In a preferred embodiment of the present invention, to avoid damage to the first pressure member 405 due to direct hard contact, and to ensure that the first pressure member 405 has a certain buffering function when pressurizing the top of the subway, preventing deformation of the subway top caused by sudden changes in pressure, the measures taken are as follows: Figure 5-6As shown, the first connecting frame includes two insert rods 406 arranged opposite each other on both sides of the first pressure member 405. The upper end of each insert rod 406 is inserted into a corresponding first support rod 403, and a rigid spring 407 is fitted around the insert rod 406. The two ends of the rigid spring 407 are fixed to the first pressure member 405 and the first support rod 403, respectively. The upper end of the first support rod 403 is fixedly connected to the corresponding first connecting longitudinal beam 401. Thus, during the downward movement of the two first connecting longitudinal beams 401 driven by the first hydraulic cylinder 402, the first pressure member 405 contacts the upper surface of the excavated foundation 600. As the first connecting longitudinal beam 401 continues to move downward, the length of the insert rod 406 inserted into the first support rod 403 increases, and the rigid spring 407 is in a compressed and energy-storing state, thereby causing the clamping force of the first pressure member 405 on the excavated foundation 600 to gradually and steadily increase. Furthermore, since the structure of the second connecting frame in this embodiment is the same as that of the first connecting frame, the connection method between the second pressure member 505 and the second support rod 503 is the same as that between the first pressure member 405 and the first support rod 403. As a result, the second pressure member 505 can also be elastically pressed onto the excavated foundation 600.

[0025] In a preferred embodiment of the present invention, both the first pressure member 405 and the second pressure member 505 are plate-like structures or assembled beam-like structures. When a plate-like structure is used, such as Figure 5-6 As shown, this is generally suitable for shallow excavation depths, where a small amount of clamping force can compensate for the loss of clamping force at the top of the subway. When using a prefabricated beam structure, such as... Figure 7-8As shown, this design is generally suitable for situations with deeper excavations. In such cases, as the excavation depth increases, the clamping force required by the assembled beam structure gradually increases, necessitating high strength from the assembled beam structure. In this embodiment, the width of the assembled beam structure gradually increases from top to bottom. This ensures that when the first support rod 403 or the second support rod 503 presses down on the assembled beam structure, the downward pressure is distributed downwards and outwards to the lower part of the assembled beam structure. This not only ensures that the assembled beam structure can withstand greater external forces but also distributes the external forces evenly to the lower end of the assembled beam structure, resulting in uniform stress on the compressed excavated foundation 600. The advantage of using an assembled beam structure in this embodiment is its ease of transportation and on-site assembly. In this embodiment, the lower parts of both the first pressure member 405 and the second pressure member 505 are arc-shaped structures, and these arc-shaped structures bulge downwards. The main purpose of this method is that when the first pressurizing component 405 and the second pressurizing component 505 alternately pressurize the excavated foundation 600, there is a certain distance between adjacent first pressurizing components 405 or adjacent second pressurizing components 505. In this way, the uniformity of force on the top of the subway is slightly insufficient during the vertical pressurization process. In this embodiment, the lower part of the first pressurizing component 405 and the second pressurizing component 505 is designed as an arc-shaped structure. When the first pressurizing component 405 or the second pressurizing component 505 pressurizes the excavated foundation 600, the external force of the pressurization is distributed through the arc-shaped structure and evenly divided into multiple components extending radially along the arc-shaped structure. This causes the excavated foundation 600 between adjacent first pressurizing components 405 or adjacent second pressurizing components 505 to also be subjected to pressure, which is gradually transmitted to the pressure sensor. In summary, the lower part of the first pressure member 405 and the second pressure member 505 in this embodiment is designed as an arc-shaped structure. The purpose is to enable the excavated foundation 600 to withstand a relatively uniform pressure during the process of the first pressure member 405 and the second pressure member 505 alternately pressurizing the excavated foundation 600.

[0026] As a preferred embodiment of the present invention, such as Figure 9-10As shown, the excavation mechanism 700 includes a drive unit, a transmission unit 701, and a rotary drilling unit 702. The drive unit is driven by either the first pressurizing mechanism 400 or the second pressurizing mechanism 500. The drive unit is also driven by the rotary drilling unit 702 via the transmission unit 701. The rotary drilling unit 702 excavates the protrusion portion 601 of the foundation 600, forming a groove 602 in the protrusion portion 601. A new protrusion portion 601 is formed between two adjacent grooves 602. The working principle of this embodiment is as follows: the drive unit travels along the length of the protrusion portion 601, moving along the first pressurizing mechanism 400 or the second pressurizing mechanism 500. As the drive unit travels, it drives the rotary drilling unit 702 via the transmission unit 701, and the rotary drilling unit 702 excavates the protrusion portion 601, turning it into a groove 602.

[0027] As a preferred embodiment of the present invention, such as Figure 9-10As shown, the drive unit includes a drive motor or a hydraulic motor. A guide seat 704 is connected to the lower end of the drive unit. The construction personnel can install the slide rail 408 on the corresponding first pressurizing mechanism 400 or second pressurizing mechanism 500. The guide seat 704 is slidably connected to the slide rail 408, and a rack 409 is detachably installed on the first pressurizing mechanism 400 or second pressurizing mechanism 500. The length direction of the rack 409 is the same as that of the guide rail 408. In this embodiment, a traveling gear 703 is coaxially installed on the output shaft 705 of the drive unit. The traveling gear 703 meshes with the rack 409. During the operation of the drive unit, its output shaft 705 drives the traveling gear 703 to rotate, so that the drive unit moves along the slide rail 408. In this embodiment, the rotary drilling unit 702 includes a drive rod 7021 and a drill bit 7023. The drive rod 7021 is constructed with helical blades 7022 extending helically along its axial direction, and the drill bit 7023 is installed at the lower end of the drive rod 7021. The transmission unit 701 includes a transmission box 7011, a first bevel gear 7012, and a second bevel gear 7013. The axes of the first bevel gear 7012 and the second bevel gear 7013 are perpendicularly aligned within the transmission box 7011, and they mesh with each other. The first bevel gear 7012 is mounted on the output shaft 705 of the drive unit, and the second bevel gear 7013 is mounted on the upper end of the drive rod 7021. During the rotation of the output shaft 705 of the drive unit, the drive rod 7021 rotates via the transmission of the first bevel gear 7012 and the second bevel gear 7013. This causes the drill bit 7023 and the spiral blade 7022 to rotary excavate the protrusion 601 of the excavated foundation 600. As the drive unit moves along the slide rail 408, a groove 602 is excavated. The excavated soil must be removed promptly. When rotary excavation is required on another boss 601, the rack 409 and slide rail 408 are disassembled and installed on the corresponding first pressure mechanism 400 or second pressure mechanism 500. Then, the excavation mechanism 700 is hoisted to the corresponding position by a crane and the excavation mechanism 700 is assembled with the slide rail 408.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., 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 method for maintaining clamping pressure during the excavation and construction of the foundation at the top of a subway station, characterized in that, Includes the following steps: S1. Anchor multiple fixed columns on the ground, avoiding the top of the subway, and install multiple pressure sensors below the excavation site on the top of the subway. S2. The working frame is fixed to the ground by the aforementioned multiple fixed columns. A first pressurizing mechanism and a second pressurizing mechanism are installed on the working frame, and the first pressurizing mechanism and the second pressurizing mechanism alternately pressurize the excavated foundation. The working frame is connected to each fixed column by multiple stepping travel mechanisms, and the fixed columns are set vertically. As the first pressurizing mechanism and the second pressurizing mechanism alternately pressurize the excavated foundation, and as the excavation mechanism gradually excavates downward, the stepping travel mechanism drives the working frame to move downward along the fixed columns. When the stepping travel mechanism and the working frame are disturbed by the soil around the fixed columns, the soil around the fixed columns needs to be cleared manually. S3. The pressure value detected by the pressure sensor is used to control the first pressurization mechanism to pressurize the excavated foundation so that the pressure value detected by the pressure sensor reaches the predetermined value. S4. Control the excavation mechanism to move. The excavation foundation at the second pressurization mechanism, which has not pressurized the excavated foundation, is excavated by the excavation mechanism, so that a groove is formed below the second pressurization mechanism. S5. Remove the excavated soil, then control the second pressurizing mechanism to extend its lower end into the groove and pressurize the excavated foundation, and control the first pressurizing mechanism to release the pressure on the excavated foundation. S6. Then, control the excavation mechanism to excavate the foundation at the first pressurization mechanism, so that a groove is formed below the first pressurization mechanism. S7. Remove the excavated soil, then control the first pressurizing mechanism to extend its lower end into the corresponding groove and pressurize the excavated foundation. Control the second pressurizing mechanism to release the pressure on the excavated foundation. S8. Repeat steps S3-S7 until the foundation of the subway top is excavated to the predetermined depth.

2. The method for maintaining clamping pressure during the excavation of the subway roof foundation as described in claim 1, characterized in that: The stepping travel mechanism includes a vertical hydraulic cylinder connected to the work frame. A first hydraulic clamp and a second hydraulic clamp are respectively connected to the cylinder body and cylinder rod of the vertical hydraulic cylinder, and the first hydraulic clamp and the second hydraulic clamp are both fitted onto the corresponding fixed column.

3. The method for maintaining clamping pressure during the excavation and construction of the subway top foundation according to claim 1, characterized in that: The first pressurizing mechanism includes two first connecting longitudinal beams arranged side by side. Each first connecting longitudinal beam is connected to the working frame through multiple first hydraulic cylinders. A first pressurizing component is arranged at intervals between the two first connecting longitudinal beams along the length direction of the first connecting longitudinal beams. The first pressurizing component is connected to the two first connecting longitudinal beams through a first connecting frame.

4. The method for maintaining clamping pressure during the excavation of the subway roof foundation as described in claim 3, characterized in that: The second pressurizing mechanism includes two second connecting longitudinal beams arranged side by side. Each second connecting longitudinal beam is connected to the working frame through multiple second hydraulic cylinders. A second pressurizing component is arranged at intervals along the length of the second connecting longitudinal beam between the two second connecting longitudinal beams. The second pressurizing component is connected to the two second connecting longitudinal beams through a second connecting frame. The second pressurizing component and the first pressurizing component are alternately arranged on the excavated foundation surface.

5. The method for maintaining clamping pressure during the excavation of the subway roof foundation as described in claim 4, characterized in that: The first pressure member and the second pressure member have the same structure, and the first connecting frame and the second connecting frame have the same structure. The first connecting frame includes two insert rods that are arranged opposite to each other on both sides of the first pressure member. The upper end of each insert rod is inserted into the first support rod, and a rigid spring is fitted on the outside of the insert rod. The two ends of the rigid spring are fixed to the first pressure member and the first support rod, respectively. The upper end of the first support rod is fixedly connected to the corresponding first connecting longitudinal beam.

6. A method for maintaining clamping pressure during the excavation and construction of the subway roof foundation according to any one of claims 3-5, characterized in that: The first pressure-applying component is a plate-like structure or an assembled beam-like structure.

7. The method for maintaining clamping pressure during the excavation of the subway roof foundation as described in claim 6, characterized in that: The lower part of the first pressure member has an arc-shaped structure, and the arc-shaped structure protrudes downward.

8. The method for maintaining clamping pressure during the excavation of the subway roof foundation according to claim 1, characterized in that: The excavation mechanism includes a drive unit that is connected to the first pressurization mechanism or the second pressurization mechanism. The drive unit is connected to the rotary drilling unit through the transmission unit. The rotary drilling unit excavates the protruding part of the foundation so that the protruding part forms a groove.

9. A method for maintaining clamping pressure during the excavation of a subway roof foundation as described in claim 8, characterized in that: The drive unit includes a drive motor or a hydraulic motor; a guide seat is connected to the lower end of the drive unit, the guide seat is slidably connected to a slide rail detachably mounted on the first or second pressurizing mechanism, a rack is detachably mounted on the first or second pressurizing mechanism, and a traveling gear that meshes with the rack is coaxially mounted on the output shaft of the drive unit; the rotary drilling unit includes a drive rod with helical blades, and a drill bit is mounted on the lower end of the drive rod; the transmission unit includes a first bevel gear and a second bevel gear disposed in a transmission box and meshing with each other, the first bevel gear is mounted on the output shaft of the drive unit, and the second bevel gear is mounted on the upper end of the drive rod.

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