Soft soil foundation pit servo type steel combined support active pressurizing device

Abstract

This invention relates to the field of building structure construction equipment technology, and in particular to an active pressurization device for a servo-driven steel composite support for soft soil foundation pits. The device includes an outer shell fixedly connected to a steel profile by bolts. The outer shell contains a first chamber and a second chamber arranged from top to bottom, connected from left to right by a first through hole and a second through hole, respectively. An end cap is fixedly installed at the end of the outer shell, and the end cap contains a first piston hole and a second piston hole arranged from top to bottom. A drive piston rod is disposed between the second piston hole and the second chamber. A first oil inlet hole and a second oil inlet hole are sequentially formed vertically at the top of the first chamber. This invention, through a bidirectional limiting structure of a limiting rod and limiting holes, maintains a locked state even when the drive piston rod is under tension, preventing the support from slipping out. This bidirectional locking capability complements the unidirectional pressure-holding characteristic of the hydraulic system, covering the safety requirements of the soft soil foundation pit support under all stress conditions.

Description

Technical Field

[0001] This invention relates to the field of building structure construction equipment technology, and in particular to a servo-driven steel composite support active pressure device for soft soil foundation pits. Background Technology

[0002] In soft soil foundation pit engineering, to control the horizontal displacement of the retaining structure and protect the surrounding environment, an active pressure device combining steel composite supports and hydraulic jacks is typically used. This device applies a controllable axial force to the retaining structure by installing hydraulic jacks at the support ends, thereby balancing the changes in soil pressure caused by foundation pit excavation. The support force is also adjusted in real time based on monitoring data to address the increase in soil pressure caused by soft soil rheology.

[0003] In existing technologies, such as Chinese patent CN202626999U, a foundation pit support system employing an active deformation control design method is disclosed. This system includes several steel supports and a steel support axial force servo system. An automatic control system compares and analyzes pre-set axial force control thresholds and monitoring results from various detection elements, and adjusts the support force of the steel supports on the retaining structure by controlling the hydraulic system. Furthermore, related research indicates that actively applying axial force through the servo system can reduce the horizontal deformation of the foundation pit retaining structure by approximately 40%. In the aforementioned existing devices, a sealing assembly is typically provided between the piston rod and the cylinder body of the hydraulic cylinder. This sealing assembly includes at least a dustproof ring embedded inside the cylinder body end cap, a piston rod sealing ring, and a guide support ring to prevent hydraulic oil leakage and prevent external contaminants from entering.

[0004] However, the existing device, in pure hydraulic locking mode, relies on the pressure-holding capacity of the hydraulic system to maintain the axial force. Due to the compressibility of hydraulic oil and the unavoidable internal leakage in the piston pump, hydraulic valves, and piston rod sealing components within the hydraulic system, the piston rod will continuously and passively retract during long-term construction of soft soil foundation pits, leading to a gradual decrease in the axial force of the support. Secondly, the rheological properties of soft soil cause the retaining structure to continuously creep under constant earth pressure. This deformation, transmitted to the hydraulic cylinder, further exacerbates the piston rod retraction, creating a vicious cycle of decreasing support force and soil deformation. The servo system needs to frequently start the hydraulic pump for pressure replenishment, resulting in increased energy consumption, system overheating, and response delays, leading to a risk of instability in the foundation pit support.

[0005] Therefore, it is necessary to provide a servo-driven steel composite support active pressurization device for soft soil foundation pits to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides an active pressurization device for servo-type steel composite support in soft soil foundation pits.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a servo-type steel combined support active pressurization device for soft soil foundation pit, including an outer shell fixedly connected to the steel by bolts, wherein the inner surface of the outer shell is provided with a first chamber and a second chamber from top to bottom, and the first chamber and the second chamber are connected from left to right by a first through hole and a second through hole, respectively; an end cover is fixedly installed at the end of the outer shell, and a first piston hole and a second piston hole are provided inside the end cover from top to bottom, and a driving piston rod is provided between the second piston hole and the second chamber;

[0008] The top of the first chamber has a first oil inlet and a second oil inlet in sequence along the vertical direction. Hydraulic oil pipes are connected to the outer sides of both the first and second oil inlets. A limit ring is fixedly installed on the inner wall of the first chamber between the first and second oil inlets. An unlocking piston rod is set between the two limit rings. A ball valve is set on the inner wall of the first chamber between the first through hole and the first oil inlet. The head of the ball valve is connected to one end of the unlocking piston rod through a horizontal rod. A sealing part is horizontally inserted into the inside of the first piston hole. One end of the sealing part is concentrically connected to one end face of the unlocking piston rod. The other end of the sealing part is connected to a limit block through a support bracket. Limit holes are equidistantly opened on the end face of the limit block.

[0009] The outer side of the end cap is symmetrically equipped with slide rails via a fixing bracket. Slider is installed inside the slide rail. The two sliders inside the slide rail on one side are connected by a pin. A locking arm is rotatably installed on the pin. The end of the locking arm is hinged to the outer wall of the drive piston rod near the end.

[0010] A U-shaped plate is fixedly installed on the outer side of the two sliders. A limit rod is welded at the center of the bottom of the U-shaped plate, and the limit rod and the limit hole are mating components.

[0011] Preferably, the support frame includes track frames symmetrically distributed on the outside of the drive piston rod, and the track frames are connected and fixed to the limiting block by a sliding fit. The two track frames are fixedly connected by a bracket. Side plates are symmetrically installed on both sides of any track frame. A T-shaped rod is inserted into the side plate. One end of the T-shaped rod is fixed to the surface of the end cover, and a support spring is sleeved on the T-shaped rod. The limiting block has a threaded hole inside, and a threaded rod is installed in the threaded hole. The threaded rod is rotatably connected to the track frame.

[0012] Preferably, the sealing part includes a synchronizing rod that is slidably inserted into the first piston hole area. One end of the synchronizing rod is connected to the track frame, and the other end of the synchronizing rod is inserted into the first chamber through the second through hole and symmetrically mounted with baffles on its outer wall. A movable plate is sleeved between the two baffles. A connecting pipe is fixedly installed on the outer ring of the movable plate. The end of the connecting pipe is concentrically fixed to the side wall of the unlocking piston rod. An L-shaped rod is fixedly installed on the outer wall of the synchronizing rod near the second oil inlet hole.

[0013] Preferably, the contact surface between the slider and the slide rail is equipped with ball bearings, and the area where the ball bearings are located is coated with lubricating grease.

[0014] Preferably, the slider, pin, and locking arm are all components made of high-strength steel.

[0015] Preferably, the bottom end face of the track frame is provided with a placement groove, and a silicone pad is embedded in the placement groove.

[0016] Preferably, a sealing ring is provided at the contact area between the outer wall of the unlocking piston rod and the inner wall of the first chamber to separate the hydraulic oil entering through the first oil inlet and the second oil inlet.

[0017] Preferably, at least one sealing ring is installed between the outer wall of the synchronizing rod and the inner wall of the first piston hole to prevent hydraulic oil in the first chamber from leaking along the outer wall of the synchronizing rod to the outside of the end cap.

[0018] Compared with related technologies, the active pressurization device for servo-driven steel composite support in soft soil foundation pits provided by this invention has the following advantages:

[0019] (1) This invention provides an active pressurization device for servo-type steel composite support in soft soil foundation pits. The rigid engagement of the limiting rod and the limiting hole in this invention changes the position constraint of the driving piston rod from an elastic constraint dependent on the volume stiffness of hydraulic oil to a rigid constraint of metal contact. This physically cuts off the path for the soft soil rheology to transmit displacement to the hydraulic system, so that the long-term maintenance of the support axial force is no longer affected by the hydraulic oil compression and system leakage. Even if the soft soil pressure continues to increase, the retraction displacement of the driving piston rod is limited within the fit clearance range between the limiting rod and the limiting hole, thereby controlling the flow. The additional deformation caused by the change is constrained within an acceptable engineering tolerance; through the bidirectional limiting structure of the limiting rod and limiting hole, the driving piston rod remains locked under tension, preventing the support from falling off. This bidirectional locking capability complements the unidirectional pressure holding characteristic of the hydraulic system, covering the safety requirements of the soft soil foundation pit support under all stress conditions. When the support needs to be removed after the foundation pit bottom slab construction is completed, the driving piston rod can be retracted in stages and locked sequentially at each locking point through hydraulic control to achieve graded unloading, thereby reducing the rebound deformation of the retaining structure caused by sudden unloading.

[0020] (2) This invention provides an active pressurization device for servo-type steel combined support in soft soil foundation pits. Through the setting of threaded rod and adjusting handwheel, the operator can make precise fine adjustment of the initial position of the limit block according to the actual working conditions on site, thereby changing the correspondence between the locking point and the extension length of the drive piston rod, improving the on-site adaptability and adjustment flexibility of the device. During the movement of the unlocking piston rod, the moving plate is driven to move. After the moving plate moves a certain distance, it moves with the baffle and drives the synchronous rod to move, so that the overall movement distance of the sealing part is less than that of the unlocking piston rod, reducing the compression of the support spring, and the installation length of the support spring can be further shortened, so that the overall transverse length of the outer shell and the support frame is shortened, thereby reducing the axial dimension of the entire device, making it more suitable for installation and use in narrow spaces such as foundation pits. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure and construction status of the present invention;

[0022] Figure 2 This is a partial front view of the structure of the present invention;

[0023] Figure 3 This is a partial structural cross-sectional view of the present invention;

[0024] Figure 4 For the present invention Figure 2 A magnified view of a portion of region A in the middle;

[0025] Figure 5 For the present invention Figure 3 A magnified view of a portion of region B in the middle;

[0026] Figure 6 For the present invention Figure 3 A magnified view of a portion of region C in the middle;

[0027] Figure 7 For the present invention Figure 3 A magnified view of a portion of region D in the middle;

[0028] The following are the labeling elements in the diagram: 1. Outer shell, 2. End cap, 3. Support bracket, 4. Limiting block, 5. Fixing bracket, 6. Slide rail, 11. First chamber, 12. Second chamber, 13. Drive piston rod, 14. First through hole, 15. Second through hole, 16. Limiting ring, 17. Unlocking piston rod, 1a. First oil inlet, 1b. Second oil inlet, 21. First piston hole, 22. Second piston hole, 23. Sealing part, 231. Synchronizing rod, 232. Baffle plate, 233. Movable plate, 234. Connecting pipe, 235. L-shaped rod, 31. Track frame, 32. Bracket, 33. Side plate, 34. T-shaped rod, 35. Support spring, 36. Threaded rod, 41. Limiting hole, 42. Threaded hole, 61. Slider, 62. Pin, 63. Locking arm, 181. Horizontal rod. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0030] Furthermore, the terms used below are defined based on the functionality of this invention and may vary depending on the user's, operator's, or conventions. Therefore, these terms are defined based on the entire contents of this specification.

[0031] Please see Figures 1-7 The present invention discloses a servo-type steel combined support active pressurization device for soft soil foundation pit, comprising an outer shell 1 fixedly connected to the steel profile by bolts, wherein the inner surface of the outer shell 1 is provided with a first chamber 11 and a second chamber 12 from top to bottom, and the first chamber 11 and the second chamber 12 are connected from left to right by a first through hole 14 and a second through hole 15, respectively, and an end cap 2 is fixedly installed at the end of the outer shell 1;

[0032] The end cap 2 has a first piston hole 21 and a second piston hole 22 arranged from top to bottom. A drive piston rod 13 is arranged between the second piston hole 22 and the second chamber 12. The end of the drive piston rod 13 is fixedly connected to the profile steel. The connection method is generally to use high-strength bolts for fixing.

[0033] The top of the first chamber 11 is provided with a first oil inlet hole 1a and a second oil inlet hole 1b in sequence along the vertical direction. The outer sides of the first oil inlet hole 1a and the second oil inlet hole 1b are connected to hydraulic oil pipes, and the ends of the hydraulic oil pipes are connected to hydraulic pumps. The hydraulic pumps supply oil through the hydraulic oil pipes.

[0034] A limiting ring 16 is fixedly installed on the inner wall of the first chamber 11, between the first oil inlet 1a and the second oil inlet 1b. An unlocking piston rod 17 is provided between the two limiting rings 16. For ease of explanation, as follows... Figure 3The two limiting rings 16 are distinguished by the L end and the R end. The first chamber 11, the second chamber 12, the first through hole 14 and the second through hole 15 are combined to form a hydraulic oil flow chamber. At the same time, the unlocking piston rod 17 is used as the dividing line to divide the flow chamber into a left flow chamber and a right flow chamber.

[0035] Meanwhile, a sealing ring is provided at the contact area between the outer wall of the unlocking piston rod 17 and the inner wall of the first chamber 11 to separate the hydraulic oil entering through the first oil inlet 1a and the second oil inlet 1b. By setting this sealing ring, the hydraulic oil is effectively prevented from flowing across the two sides of the unlocking piston rod 17 (i.e., the left flow chamber and the right flow chamber) when the first oil inlet 1a and the second oil inlet 1b are supplied with oil. This ensures that the unlocking piston rod 17 can be driven independently by different oil inlets, thereby improving the accuracy and reliability of hydraulic control.

[0036] A ball valve 18 is provided on the inner wall of the first chamber 11 and between the first through hole 14 and the first oil inlet hole 1a. The head of the ball valve 18 is connected to one end of the unlocking piston rod 17 through a horizontal rod 181. The distance between the two limiting rings 16 at the L end and the R end is less than the maximum horizontal compression distance of the ball valve 18 spring, so that there is a certain distance limit between them.

[0037] The aforementioned spacing restriction ensures that when the unlocking piston rod 17 is moved to the position of the limit ring 16 by hydraulic thrust, the spring of the ball valve 18 has not yet reached its maximum compression state, thus preserving the spring's reset capability and preventing the spring from being damaged or failing due to excessive compression.

[0038] The sealing part 23 is horizontally inserted into the inside of the first piston hole 21. One end of the sealing part 23 is concentrically connected to one end face of the unlocking piston rod 17. The other end of the sealing part 23 is connected to the limiting block 4 through the support bracket 3. The end face of the limiting block 4 is provided with limiting holes 41 at equal intervals.

[0039] Multiple equidistant limiting holes 41 provide multiple mechanical locking points for the device, enabling the drive piston rod 13 to be reliably locked at different extension lengths, adapting to the support length requirements of different working conditions in foundation pit support;

[0040] The outer side of the end cover 2 is symmetrically equipped with slide rails 6 via a fixing bracket 5. A slider 61 is installed inside the slide rail 6. The two sliders 61 inside the slide rail 6 on one side are connected by a pin 62. A locking arm 63 is rotatably installed on the pin 62. The end of the locking arm 63 is hinged to the outer wall of the drive piston rod 13 near the end.

[0041] A U-shaped plate 64 is fixedly installed on the outer side of the two sliders 61. A limiting rod 65 is welded at the center of the bottom of the U-shaped plate 64. The limiting rod 65 and the limiting hole 41 are mating components. Under normal conditions, the limiting rod 65 is inserted into the limiting hole 41, and the slider 61 cannot slide in the slide rail 6. In order to ensure the smoothness of the slider 61 sliding in the slide rail 6, the contact surface between the slider 61 and the slide rail 6 is equipped with balls, and the area where the balls are set is coated with lubricating grease.

[0042] like Figure 3 As shown, after the hydraulic oil enters through the first oil inlet 1a, it pushes the steel ball valve 18 to open under pressure. At the same time, during the opening process of the steel ball valve 18, it drives the unlocking piston rod 17 to move toward the L end limiting ring 16 and abut against its outer wall. During the movement of the unlocking piston rod 17, it drives the fixing frame 5 to move horizontally through the sealing part 23, thereby driving the limiting block 4 to move horizontally. The limiting hole 41 provided on one side of the limiting block 4 separates from the limiting rod 65.

[0043] Hydraulic oil enters the left flow chamber from the ball valve 18, pushing the drive piston rod 13 to extend and actively pressurize one side of the steel profile. During the extension process, the drive piston rod 13 simultaneously drives the locking arm 63 to move. The angle between the locking arm 63 and the drive piston rod 13 gradually decreases, so that the other end of the locking arm 63 has a pulling force. This pulling force drives the slider 61 connected to the other end of the locking arm 63 to slide in the slide rail 6. When the drive piston rod 13 moves to the designated position, the hydraulic oil stops flowing, and the ball valve 18 returns to the initial position under the action of elasticity. The unlocking piston rod 17 moves synchronously toward the limit ring 16 at the R end, and drives the limit hole 41 set on one side of the limit block 4 to re-insert into the outer wall of the limit rod 65.

[0044] Similarly, when hydraulic oil enters from the second oil inlet 1b, the hydraulic oil first applies pressure to the unlocking piston rod 17, causing the unlocking piston rod 17 to move from the limiting ring 16 at the R end toward the limiting ring 16 at the L end and drive the steel ball valve 18 to open through the horizontal rod 181, so that the hydraulic oil in the left flow chamber can flow back from the first oil inlet 1a. In this embodiment, regardless of the extension and retraction of the driving piston rod 13, mechanical self-locking can be completed through the locking arm 63, the limiting rod 65 and other structures, and there are many mechanical self-locking points.

[0045] In this embodiment, by rigidly engaging the limiting rod 65 with the limiting hole 41, the position constraint of the driving piston rod 13 is changed from an elastic constraint that depends on the volume stiffness of the hydraulic oil to a rigid constraint of metal contact. This physically cuts off the path of soft soil rheology to transmit displacement to the hydraulic system, so that the long-term maintenance of the support axial force is no longer affected by the hydraulic oil compression and leakage in the system.

[0046] The limiting rod 65 and the limiting hole 41 form an irreversible mechanical block. Even if the soft soil pressure continues to increase, the retraction displacement of the driving piston rod 13 is limited within the fit gap between the limiting rod 65 and the limiting hole 41, thereby constraining the additional deformation caused by rheology within an acceptable engineering tolerance. Through the bidirectional limiting structure of the limiting rod 65 and the limiting hole 41, the driving piston rod 13 remains locked under tension, preventing the support from slipping. This bidirectional locking capability complements the unidirectional pressure holding characteristic of the hydraulic system, covering the safety requirements of the soft soil foundation pit support under all stress conditions. When the foundation pit bottom slab is completed and the support needs to be removed, the driving piston rod 13 can be retracted in stages and locked sequentially at each locking point through hydraulic control to achieve graded unloading, thereby reducing the rebound deformation of the retaining structure caused by sudden unloading.

[0047] Meanwhile, the slider 61, pin 62 and locking arm 63 are all components made of high-strength steel. The use of high-strength steel to manufacture key load-bearing components effectively improves the structural strength and fatigue resistance of the device under heavy load conditions, ensuring the reliability and safety of long-term use.

[0048] Furthermore, a scale can be applied to the surface of the drive piston rod 13, with the scale marking the corresponding movement position of the limit rod 65, so that the limit rod 65 can accurately fall into the limit hole 41.

[0049] In another embodiment, reference is made to Figures 1-7 As shown, the support frame 3 includes track frames 31 symmetrically distributed on the outside of the drive piston rod 13, and the track frames 31 are connected and fixed to the limiting block 4 through a sliding fit. The two track frames 31 are fixedly connected by a bracket 32 ​​to ensure that the movement trajectories of the two track frames 31 are consistent.

[0050] Side plates 33 are symmetrically installed on both sides of any track frame 31. T-shaped rods 34 are inserted into the side plates 33. One end of the T-shaped rod 34 is fixed to the surface of the end cover 2, and a support spring 35 is sleeved on the T-shaped rod 34. That is, the track frame 31 is directly driven to move along the T-shaped rod 34 through the sealing part 23. During the movement, the side plate 33 generates a squeezing force on the support spring 35. This squeezing force can drive the track frame 31 to reset as a driving force.

[0051] The limiting block 4 has a threaded hole 42 inside, and a threaded rod 36 is installed in the threaded hole 42. The threaded rod 36 is rotatably connected to the track frame 31. An adjusting handwheel is fixedly installed at the end of the threaded rod 36 to drive the threaded rod 36 to rotate in the threaded hole 42, so as to adjust the relative position between the limiting block 4 and the track frame 31, thereby changing the position of the limiting hole 41 on one side of the limiting block 4 relative to the limiting rod 65.

[0052] By using the threaded rod 36 and the adjusting handwheel, the operator can precisely fine-tune the initial position of the limit block 4 according to the actual working conditions on site, thereby changing the correspondence between the locking point and the extension length of the drive piston rod 13, improving the on-site adaptability and adjustment flexibility of the device.

[0053] In another embodiment, reference is made to Figures 1-7 The sealing part 23 includes a synchronizing rod 231 that is slidably inserted into the region of the first piston hole 21. One end of the synchronizing rod 231 is connected to the track frame 31, and the other end of the synchronizing rod 231 is inserted into the first chamber 11 through the second through hole 15. Baffles 232 are symmetrically installed on its outer wall. A movable disc 233 is sleeved between the two baffles 232. The movable disc 233 can slide on the outer wall of the synchronizing rod 231, and the sliding distance is between the two baffles 232.

[0054] A connecting pipe 234 is fixedly installed on the outer ring of the movable disc 233. The end of the connecting pipe 234 is concentrically fixed to the side wall of the unlocking piston rod 17. An L-shaped rod 235 is fixedly installed on the outer wall of the synchronizing rod 231 near the second oil inlet hole 1b. In this embodiment, the movable disc 233 moves during the movement of the unlocking piston rod 17. After the movable disc 233 moves a certain distance, it moves with the baffle 232 and drives the synchronizing rod 231 to move. This makes the overall movement distance of the sealing part 23 less than that of the unlocking piston rod 17, reducing the compression of the support spring 35. The installation length of the support spring 35 can be further shortened, which shortens the overall transverse length of the outer shell 1 and the support frame 3, thereby reducing the axial dimension of the entire device and making it more suitable for installation and use in narrow spaces such as pits.

[0055] The bottom end face of the track frame 31 is provided with a placement groove, and a silicone pad is embedded in the placement groove. When the track frame 31 contacts the surface of the end cover 2, the silicone pad reduces the wear between the two.

[0056] At least one sealing ring is installed between the outer wall of the synchronizing rod 231 and the inner wall of the first piston hole 21. The sealing ring prevents the hydraulic oil in the first chamber 11 from leaking along the outer wall of the synchronizing rod 231 to the outside of the end cover 2.

[0057] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A servo-driven steel composite support active pressure device for soft soil foundation pits, comprising an outer shell (1) fixedly connected to the steel profile by bolts, characterized in that, The outer shell (1) has a first chamber (11) and a second chamber (12) arranged from top to bottom. The first chamber (11) and the second chamber (12) are connected from left to right through a first through hole (14) and a second through hole (15). An end cap (2) is fixedly installed at the end of the outer shell (1). The end cap (2) has a first piston hole (21) and a second piston hole (22) arranged from top to bottom. A drive piston rod (13) is arranged between the second piston hole (22) and the second chamber (12). The top of the first chamber (11) is vertically provided with a first oil inlet (1a) and a second oil inlet (1b). Hydraulic oil pipes are connected to the outer sides of both the first oil inlet (1a) and the second oil inlet (1b). A limit ring (16) is fixedly installed on the inner wall of the first chamber (11) between the first oil inlet (1a) and the second oil inlet (1b). An unlocking piston rod (17) is provided between the two limit rings (16). The inner wall of the first chamber (11) is located at the first through hole (14). A ball valve (18) is provided between the first oil inlet (1a) and the first oil inlet (17). The head of the ball valve (18) is connected to one end of the unlocking piston rod (17) through a horizontal rod (181). A sealing part (23) is horizontally inserted into the inside of the first piston hole (21). One end of the sealing part (23) is concentrically connected to one side end face of the unlocking piston rod (17). The other end of the sealing part (23) is connected to a limiting block (4) through a support bracket (3). Limiting holes (41) are opened at equal intervals on the end face of the limiting block (4). The outer side of the end cap (2) is symmetrically equipped with slide rails (6) through the fixing bracket (5). Slider (61) is installed in the slide rail (6). The two sliders (61) in the slide rail (6) on one side are connected by a pin (62). A locking arm (63) is rotatably installed on the pin (62). The end of the locking arm (63) is hinged to the outer wall of the drive piston rod (13) near the end. A U-shaped plate (64) is fixedly installed on the outer side of the two sliders (61). A limit rod (65) is welded at the center of the bottom of the U-shaped plate (64), and the limit rod (65) and the limit hole (41) are a mating component.

2. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 1, characterized in that, The support frame (3) includes a track frame (31) symmetrically distributed on the outside of the drive piston rod (13), and the track frame (31) is connected and fixed to the limiting block (4) through a sliding fit. The two track frames (31) are fixedly connected by a bracket (32). Side plates (33) are symmetrically installed on both sides of any track frame (31). A T-shaped rod (34) is inserted on the side plate (33). One end of the T-shaped rod (34) is fixed to the surface of the end cover (2), and a support spring (35) is sleeved on the T-shaped rod (34). A threaded hole (42) is opened inside the limiting block (4), and a threaded rod (36) is installed in the threaded hole (42). The threaded rod (36) is rotatably connected to the track frame (31).

3. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 2, characterized in that, The sealing part (23) includes a synchronizing rod (231) that is slidably inserted into the region of the first piston hole (21). One end of the synchronizing rod (231) is connected to the track frame (31), and the other end of the synchronizing rod (231) passes through the second through hole (15) and is inserted into the first chamber (11). A baffle (232) is symmetrically installed on its outer wall. A movable disc (233) is sleeved between the two baffles (232). A connecting pipe (234) is fixedly installed on the outer ring of the movable disc (233). The end of the connecting pipe (234) is concentrically fixed on the side wall of the unlocking piston rod (17). An L-shaped rod (235) is fixedly installed on the outer wall of the synchronizing rod (231) near the second oil inlet hole (1b).

4. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 1, characterized in that, The contact surface between the slider (61) and the slide rail (6) is equipped with balls, and the area where the balls are located is coated with lubricating grease.

5. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 1, characterized in that, The slider (61), pin (62) and locking arm (63) are all components made of high-strength steel.

6. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 2, characterized in that, The bottom end face of the track frame (31) is provided with a placement groove, and a silicone pad is embedded in the placement groove.

7. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 1, characterized in that, A sealing ring is provided at the contact area between the outer wall of the unlocking piston rod (17) and the inner wall of the first chamber (11) to separate the hydraulic oil entering through the first oil inlet (1a) and the second oil inlet (1b).

8. The active pressurization device for servo-driven steel composite support in soft soil foundation pits according to claim 3, characterized in that, At least one sealing ring is installed between the outer wall of the synchronizing rod (231) and the inner wall of the first piston hole (21) to prevent the hydraulic oil in the first chamber (11) from leaking along the outer wall of the synchronizing rod (231) to the outside of the end cap (2).

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