A soft foundation ultra-deep pit support structure and construction method

Abstract

The present invention discloses a soft foundation ultra-deep pit support structure, comprising a precast pile and a precast support formwork; a precast tip is fixedly installed at the bottom of the precast pile and the precast tip is press-fitted into the stabilizing layer, and the precast piles are provided in multiple groups and connected in sequence; multiple groups of precast support formwork are provided vertically and horizontally and connected in sequence; a waterproof structure is installed between two adjacent precast support formworks; a connecting rod group 1 is installed between two adjacent groups of precast piles, a connecting rod group 2 is installed on the side of the precast pile opposite to the precast support formwork, and one end of the connecting rod group 2 is suitable for installing the precast support formwork; a support is installed on the side of the precast support formwork opposite to the precast pile, and multiple groups of supports are arranged vertically, and the same connecting rod group 3 is installed on the upper and lower groups of supports, and the ends of the connecting rod group 3 and the connecting rod group 1 are arranged to slide vertically. The existing deep foundation pit retaining structure cannot complete vertical press-fitting, which easily leads to the problems of poor stability and reliability, poor turnover, and difficult recycling of the soft foundation pit retaining structure.

Description

Technical Field

[0001] The present invention relates to a soft foundation ultra-deep pit support technology, in particular to a soft foundation ultra-deep pit support structure and a construction method. Background Art

[0002] Foundation pit support is a measure used to support, reinforce, and protect the pit walls and surrounding environment to ensure the safety of underground structure construction and the surrounding environment. Common foundation pit support methods include pile support, underground diaphragm wall support, pile or wall support systems, and reinforced concrete pile support. Selection can be based on a comprehensive evaluation of the pit depth, soil quality, and other working conditions, or a reasonable combination of multiple support methods can be used.

[0003] Deep foundation pit support refers to the measures taken to support, reinforce and protect the side walls of deep foundation pits and the surrounding environment in order to ensure the safety of underground structure construction and the surrounding environment of the foundation pit. Deep foundation pit support is an important structure to ensure the safety of deep foundation pit operations, which is directly related to the safety of the project and the personal safety of related workers. Deep foundation pit support in the existing technology can be divided into cast-in-place support that requires on-site casting of pile foundations, retaining walls, etc., or retaining structures combined with piles, slabs, etc. For soft soil, due to the difficulty, high cost and long construction period of cast-in-place pile and wall forming processes, the method of directly erecting retaining structures is generally adopted. However, erecting retaining structures is also relatively difficult, and it is impossible to ensure that the retaining structures are pressed in the vertical direction, so the stability and reliability of the retaining structures cannot be guaranteed. The existing retaining structures also have the problems of poor turnover or difficulty in reuse. Summary of the Invention

[0004] The present invention solves the problem that the existing deep foundation pit retaining structure cannot complete vertical press installation, which easily leads to poor stability and reliability, poor turnover and difficult recycling of the soft foundation deep foundation pit retaining structure. Therefore, a soft foundation ultra-deep pit support structure and construction method are proposed.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A soft foundation ultra-deep pit support structure, comprising prefabricated piles and prefabricated support templates;

[0007] A prefabricated tip is fixedly installed at the bottom of the prefabricated pile and is press-fitted into the stabilization layer. Multiple groups of prefabricated piles are arranged along the support direction and are connected in sequence.

[0008] Multiple groups of prefabricated support templates are arranged vertically and horizontally along the support direction and connected in sequence;

[0009] A waterproof structure is installed between two adjacent prefabricated support formworks;

[0010] A connecting rod group 1 is installed between two adjacent groups of precast piles, and a connecting rod group 2 is installed on the side of the precast piles opposite to the precast support formwork, and one end of the connecting rod group 2 is suitable for installing the precast support formwork;

[0011] A support is installed on the side of the prefabricated support formwork opposite to the prefabricated pile. Multiple groups of supports are arranged vertically, and each group of supports is arranged at least two along the transverse direction of the prefabricated support formwork. The same group of connecting rod group three is installed on the upper and lower groups of supports, and the connecting rod group three and the two ends of the connecting rod group are arranged vertically for sliding.

[0012] Preferably, the support is provided with mounting holes, and the support is installed on the prefabricated support formwork by means of bolts passing through the mounting holes. The connecting rod group three includes a connecting pipe sleeve, which is installed on the side of the support opposite to the prefabricated pile, and a vertical position maintaining rod is installed inside the connecting pipe sleeve.

[0013] Preferably, the connecting rod group 1 and the connecting rod group 2 are telescopic rods that can freely adjust the length, and a connecting structure is installed at one end of the connecting rod group 2, which is suitable for vertical sliding cooperation of the vertical position holding rod.

[0014] Preferably, the connecting structure includes a mounting plate installed on the two ends of the connecting rod group, a guide plate is movably installed on the mounting plate, a through slot is arranged on the guide plate, a mounting groove is arranged on the mounting plate and the mounting groove is suitable for installing the guide plate, a guide groove 1 and a guide groove 2 are arranged on the side wall of the mounting groove, a guide pin is installed in each of the guide groove 1 and the guide groove 2, and the two guide pins are both installed on the side wall of the guide plate, a torsion spring is installed between the guide pin and the guide plate, and a spring 1 that abuts the guide plate is installed in the guide groove 2.

[0015] Preferably, the through slot of the guide plate is in an inclined state when in a free state and only allows the vertical position maintaining rod to pass through, and when the guide plate is in a horizontal state under the action of the connecting sleeve, only allows the connecting sleeve to pass through.

[0016] Preferably, the waterproof structure between the prefabricated support formwork includes a convex portion and a tongue and groove arranged on the side of the prefabricated support formwork, a clamping structure is installed in the tongue and groove for clamping a groove on the side of the convex portion, and an elastic locking part is installed inside the tongue and groove for locking the clamping structure, and a sealing strip is installed between two adjacent prefabricated support formworks.

[0017] Preferably, the clamping structure includes a clamping claw, a rotating groove, a slide groove one and a slide groove two, the slide groove one and the slide groove two are arranged in parallel and slide blocks are installed in the slide groove one and the slide groove two, the rotating groove is arranged on the side of the slide groove one away from the protrusion and one end is connected with the end of the slide groove one away from the slide groove two, the slide blocks are installed on both sides of the clamping claw, a pressing head is installed on the clamping claw and the pressing head is suitable for driving the clamping claw to rotate under the action of the end of the protrusion, a spring two is installed between the back side of the clamping claw and the inner wall of the tongue and groove, and a locking groove adapted to the end of the elastic locking piece is arranged on the side of the clamping claw opposite to the inner wall of the tongue and groove.

[0018] Preferably, a seepage hole is provided on the outer wall of the prefabricated support formwork, a water through hole connected to the seepage hole is provided inside the prefabricated support formwork, and a water guide belt is installed in the seepage hole and the water through hole.

[0019] Preferably, a prefabricated tip is installed at the bottom of the prefabricated supporting formwork located at the bottom, and the prefabricated tip is pressed into the stabilizing layer.

[0020] A construction method for a soft foundation ultra-deep pit support structure, the construction steps are as follows:

[0021] Step 1: According to the design requirements of the drawings, the soft foundation section is marked out to draw the position area lines of the precast piles and precast support templates. The precast piles are pressed into the soft foundation section using the pressing equipment, and the bottom precast tip is pressed into the stabilization layer.

[0022] Step 2: Install the connecting rod group 1 between two adjacent precast piles, and then vertically press-fit the precast support formwork layer by layer according to the position area line of the precast support formwork. Install the support before pressing each layer of the precast support formwork, and use the connecting pipe sleeve on the support to assemble through the vertical position retaining rod. The vertical position retaining rod is slidably matched through the connecting structure on the connecting rod group 2 to ensure the stability of the vertical press-fit of the precast support formwork, until the precast tip on the precast support formwork is pressed into the stable layer;

[0023] When the prefabricated support formwork is press-fitted, the vertical position maintaining rod is in a vertically stable sliding state under the action of the guide plate in an inclined state. When the connecting pipe sleeve acts on the guide plate, the guide plate rotates under the action of the two guide pins and moves a small distance to the side away from the connecting pipe sleeve. When the guide plate is in a horizontal state under the action of the connecting pipe sleeve, the connecting pipe sleeve can pass through the through-slot vertically and stably. After the connecting pipe sleeve passes through the through-slot, the guide plate returns to its initial state under the action of spring 1 and the torsion spring to allow the vertical position maintaining rod to slide vertically and stably.

[0024] The prefabricated support formwork is assembled vertically and horizontally in the support direction, and is connected and assembled with the tongue and groove and the convex part. After the end of the convex part enters the tongue and groove, the clamping claw is driven to rotate along the rotating groove to complete the action of clamping the convex part. As the convex part continues to enter the tongue and groove, the clamping claw and the convex part move together. When the locking groove on the clamping claw moves to the position adapted to the elastic locking part, the connection between the convex part and the tongue and groove is completed. At this time, the second spring is in a stretched state, and the sealing strip is in a crimped state.

[0025] Step 3: Excavate the foundation pit and backfill the foundation, and remove the prefabricated support formwork and prefabricated piles using lifting equipment.

[0026] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts the method of first pressing the precast piles into the stabilizing layer, and then pressing the precast support formwork until its bottom is also pressed into the stabilizing layer. Under the condition of ultra-deep foundation pit, the precast support formwork needs to be kept vertically pressed. The support, connecting pipe sleeve and vertical position retaining rod are installed on the back of the precast support formwork to achieve the structural integrity, stability and reliability of the entire precast support formwork. Another innovation of the present invention is how to ensure that the connecting pipe sleeve and the vertical position retaining rod can pass freely through the connecting structure during vertical installation. In this way, only the installation step of the vertical position retaining rod can be carried out, and there is no need to remove the connecting structure and the vertical position retaining rod before each layer of precast support formwork is pressed and then reinstalled before continuing the pressing action. The guide plate is rotated horizontally by the action of the connecting pipe sleeve and moves to the side away from the support formwork, so that the axis position of the guide plate passing through the slot is always coincident with the axis of the connecting pipe sleeve and the vertical position retaining rod, which will not cause the precast support formwork to deviate forward and backward. To ensure the prefabricated support formwork achieves a water-stopping effect, waterproof structures are installed at the joints. Seepage holes are arranged on the outside of the prefabricated support formwork, as well as internal water holes. Waterproofing is achieved around the support perimeter via water diversion belts. Clamping claws and locking structures are used within adjacent joints to complete the structural assembly and waterproofing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic cross-sectional view of the overall structure of the present invention;

[0028] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0029] Figure 3 for Figure 2 Connection diagram of the middle guide plate and the mounting plate;

[0030] Figure 4 for Figure 2 Schematic diagram of the overall structure of the middle guide plate;

[0031] Figure 5 This is the connection diagram of the two groups of prefabricated support templates on the left and right;

[0032] Figure 6 for Figure 5 Schematic diagram of the position structure of the clamping claw under medium working conditions;

[0033] Figure 7 for Figure 5 Schematic diagram of the position structure of the clamping claw under central and African working conditions.

[0034] In the picture:

[0035] 10. Precast piles; 11. Precast tips;

[0036] 20. Prefabricated support formwork; 21. Support; 22. Connecting sleeve; 23. Vertical position retaining rod; 24. Protrusion; 25. Tongue and groove; 26. Elastic locking member; 27. Clamping claw; 28. Rotation slot; 29. ​​Slide slot 1; 210. Slide slot 2; 211. Slider; 212. Spring 2; 213. Locking slot; 214. Water hole; 215. Seepage hole;

[0037] 30. Stability layer;

[0038] 40. Connecting rod group 1;

[0039] 50. Connecting rod group 2; 51. Mounting plate; 52. Guide plate; 53. Mounting slot; 54. Through-slot; 55. Guide slot 1; 56. Guide slot 2; 57. Guide pin; 58. Spring 1. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0041] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0042] Example 1, as Figures 1 to 7 As shown, a soft foundation ultra-deep pit support structure includes prefabricated piles 10 and prefabricated support templates 20;

[0043] A prefabricated tip 11 is fixedly mounted on the bottom of the prefabricated pile 10 and is press-fitted into the stabilization layer 30. Multiple groups of prefabricated piles 10 are arranged along the supporting direction and are connected in sequence.

[0044] The prefabricated support templates 20 are arranged in multiple groups vertically and horizontally along the support direction and are connected in sequence;

[0045] A waterproof structure is installed between two adjacent prefabricated support templates 20;

[0046] A connecting rod group 1 40 is installed between two adjacent groups of precast piles 10, and a connecting rod group 2 50 is installed on the side of the precast pile 10 opposite to the precast support formwork 20, and one end of the connecting rod group 2 50 is suitable for installing the precast support formwork 20; the connecting rod group 1 40 and the connecting rod group 2 50 are both telescopic rods that can freely adjust the length, and the structure is arranged in the same manner as the connecting rod 1 and connecting rod 2 in CN114809008A.

[0047] like Figure 2 and Figure 3 As shown, the precast support formwork 20 is mounted on the side opposite the precast piles 10. Multiple groups of supports 21 are arranged vertically, with each group having at least two supports 21 arranged transversely along the precast support formwork 20. The upper and lower groups of supports 21 are mounted with the same connecting rod group 3, with the ends of connecting rod group 3 and connecting rod group 2 50 arranged to slide vertically. A precast spike is mounted on the bottom of the precast support formwork 20, which is located at the bottom. The spike is press-fitted into the stabilization layer 30.

[0048] like Figure 1 As shown, the prefabricated tip at the bottom of the prefabricated support formwork 20 and the prefabricated tip 11 at the bottom of the prefabricated pile 10 are pressed into the stabilization layer 30. The top of the support structure is connected by a connecting rod group 2 50 and a vertical connecting rod group 3 between the prefabricated support formwork 20 to ensure the lateral stability of the support structure under the impact of soft soil.

[0049] like Figure 2 and Figure 3 As shown, mounting holes are provided on support 21, which is mounted to prefabricated support formwork 20 via bolts passing through the mounting holes. Connecting rod group three includes a connecting sleeve 22, which is mounted on the side of support 21 facing the prefabricated pile 10. A vertical position retaining rod 23 is installed within the sleeve. This vertical position retaining rod 23 ensures the vertical integrity of the entire prefabricated support formwork 20, while the horizontal integrity is achieved through a waterproof structure. The bottom end of the connecting sleeve 22 adopts a tapered structure.

[0050] like Figure 3As shown, a connecting structure is installed at one end of the connecting rod group 2 50, and the connecting structure is suitable for vertical sliding cooperation of the vertical position holding rod 23. The connecting structure includes a mounting plate 51 installed at the end of the connecting rod group 2 50, and a guide plate 52 is movably installed on the mounting plate 51. The guide plate 52 is provided with a through-notch 54, and a mounting groove 53 is provided on the mounting plate 51 and the mounting groove 53 is suitable for installing the guide plate 52. A guide groove 1 55 and a guide groove 2 56 are provided on the side wall of the mounting groove 53, and a guide pin shaft 57 is installed in the guide groove 1 55 and the guide groove 2 56. The two guide pin shafts 57 are both installed on the side wall of the guide plate 52, wherein a torsion spring is installed between the guide pin shaft 57 and the guide plate 52, and a spring 1 58 abutting the guide plate 52 is installed in the guide groove 2 56.

[0051] When the guide plate 52 is in a free state, the through slot 54 is in an inclined state and only allows the vertical position holding rod 23 to pass through. When the guide plate 52 is in a horizontal state under the action of the connecting sleeve 22, the connecting sleeve 22 can pass through.

[0052] When the prefabricated support formwork 20 is pressed, the vertical position maintaining rod 23 is in a vertical stable sliding state under the action of the guide plate 52 in an inclined state, that is, the through-notch 54 thereon is in an inclined state, the top of the through-notch 54 acts on the vertical position maintaining rod 23 toward the side close to the prefabricated pile 10, and the bottom of the through-notch 54 acts on the vertical position maintaining rod 23 toward the side away from the prefabricated pile 10, and at this time the guide plate 52 is in a stable state. When the connecting pipe sleeve 22 vertically acts on the guide plate 52, the guide plate 52 rotates under the action of the two guide pins 57 and moves a small distance toward the side away from the connecting pipe sleeve 22. When the guide plate 52 is in a horizontal state under the action of the connecting pipe sleeve 22, the connecting pipe sleeve 22 can pass through the through-notch 54 vertically and stably. After the connecting pipe sleeve 22 passes through the through-notch 54, the guide plate 52 is restored to its initial state under the action of spring 1 58 and the torsion spring for the vertical position maintaining rod 23 to slide vertically and stably.

[0053] like Figures 5 to 7 As shown, a sealing strip is arranged between two vertically adjacent prefabricated support formworks 20, and the sealing installation is completed in conjunction with the connecting pipe sleeve 22 and the vertical position retaining rod 23. The waterproof structure between the two adjacent prefabricated support formworks 20 on the left and right includes a protrusion 24 and a tongue and groove 25 arranged on the side of the prefabricated support formwork 20. A clamping structure is installed in the tongue and groove 25, which is suitable for clamping the groove on the side of the protrusion 24, and an elastic locking part 26 suitable for locking the clamping structure is installed inside the tongue and groove 25. A sealing strip is installed between the two adjacent prefabricated support formworks 20.

[0054] like Figures 5 to 7As shown, the clamping structure includes a clamping claw 27, a rotating groove 28, a slide groove 1 29 and a slide groove 210. The slide groove 1 29 and the slide groove 2 210 are arranged in parallel and a slider 211 is installed in the slide groove 1 29 and the slide groove 2 210. The rotating groove 28 is arranged on the side of the slide groove 1 29 away from the protrusion 24 and one end is connected with the end of the slide groove 1 29 away from the slide groove 210. The slider 211 is installed on both sides of the clamping claw 27. A pressing head is installed on the clamping claw 27 and the pressing head is suitable for driving the clamping claw 27 to rotate under the action of the end of the protrusion 24. A spring 212 is installed between the back side of the clamping claw 27 and the inner wall of the tongue and groove 25. A locking groove 213 adapted to the end of the elastic locking member 26 is arranged on the side of the clamping claw 27 opposite to the inner wall of the tongue and groove 25.

[0055] The protrusion 24 enters the tongue and groove 25, and the protrusion 24 will first act on the crimping head of the clamping claw 27, so that the clamping claw 27 clamps the groove on the outside of the protrusion 24, and then the clamping claw 27 moves together with the protrusion 24 to the depth of the tongue and groove 25 and compresses the sealing strip. When the locking groove 213 and the elastic locking piece are adapted, the clamping claw 27 can stably clamp the protrusion 24 and is in a stable state. After clamping, the sealing strip is in a compressed state.

[0056] The prefabricated support formwork 20 has seepage holes 215 formed on its outer wall. Inside the prefabricated support formwork 20, water holes 214 are arranged, communicating with the seepage holes 215. Water diversion belts are installed within the seepage holes 215 and the water diversion belts. The outer seepage holes 215 and the inner water diversion holes 214, in conjunction with the water diversion belts, divert water from the outer side of the prefabricated support formwork, thereby achieving a water-stopping effect in conjunction with the waterproof structure.

[0057] A construction method for a soft foundation ultra-deep pit support structure, the construction steps are as follows:

[0058] Step 1: According to the design requirements of the drawings, the position area lines of the precast piles 10 and the precast support templates 20 are drawn on the soft foundation section. The precast piles 10 are pressed into the soft foundation section by the pressing equipment, and the precast tip 11 at the bottom is pressed into the stabilization layer 30.

[0059] Step 2: Install the connecting rod group 1 between two adjacent precast piles 10, and then vertically press-fit the precast support formwork 20 layer by layer according to the position area line of the precast support formwork 20. Before pressing each layer of the precast support formwork 20, install the support 21, and assemble it through the vertical position retaining rod 23 using the connecting pipe sleeve 22 on the support 21. The vertical position retaining rod 23 is slidably fitted through the connecting structure on the connecting rod group 2 50 to ensure the stability of the vertical press-fitting of the precast support formwork 20, until the precast tip on the precast support formwork 20 is pressed into the stabilizing layer 30.

[0060] When the prefabricated support formwork 20 is press-fitted, the vertical position holding rod 23 is in a stable vertical sliding state under the action of the guide plate 52 in an inclined state. When the connecting pipe sleeve 22 acts on the guide plate 52, the guide plate 52 rotates under the action of the two guide pins 57 and moves a small distance to the side away from the connecting pipe sleeve 22. When the guide plate 52 is in a horizontal state under the action of the connecting pipe sleeve 22, the connecting pipe sleeve 22 can pass through the through-slot 54 in a stable vertical position. After the connecting pipe sleeve 22 passes through the through-slot 54, the guide plate 52 returns to its initial state under the action of the spring 1 58 and the torsion spring, allowing the vertical position holding rod 23 to slide stably vertically.

[0061] The prefabricated support formwork 20 is assembled vertically and horizontally in the support direction, and is connected and assembled with the tongue and groove 25 and the protrusion 24. After the end of the protrusion 24 enters the tongue and groove 25, the clamping claw 27 is actuated and drives the clamping claw 27 to rotate along the rotation groove 28 to complete the action of clamping the protrusion 24. As the protrusion 24 continues to enter the tongue and groove 25, the clamping claw 27 and the protrusion 24 move together. When the locking groove 213 on the clamping claw 27 moves to a position adapted to the elastic locking member 26, the connection between the protrusion 24 and the tongue and groove 25 is completed. At this time, the spring 212 is in a stretched state, and the sealing strip is in a crimped state.

[0062] Step 3: Excavate the foundation pit and backfill the foundation pit, and then remove the prefabricated support template 20 and prefabricated piles 10 by lifting equipment.

[0063] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. The replacement may be a replacement of a portion of a structure, device, or method step, or it may be a complete technical solution. Any equivalent replacement or modification based on the technical solution and inventive concept of the present invention shall be covered by the scope of protection of the present invention.

Claims

1. A soft foundation ultra-deep pit support structure, characterized in that: It includes prefabricated piles (10) and prefabricated support templates (20); A prefabricated tip (11) is fixedly installed at the bottom of the prefabricated pile (10), and the prefabricated tip (11) is press-fitted into the stabilizing layer (30). Multiple groups of prefabricated piles (10) are arranged along the supporting direction and are connected in sequence. Multiple groups of prefabricated support templates (20) are arranged vertically and horizontally along the support direction and are connected in sequence; A waterproof structure is installed between two adjacent groups of prefabricated support templates (20); A connecting rod group 1 (40) is installed between two adjacent groups of precast piles (10), and a connecting rod group 2 (50) is installed on the side of the precast piles (10) opposite to the precast support template (20), and one end of the connecting rod group 2 (50) is suitable for installing the precast support template (20); A support (21) is installed on one side of the prefabricated support template (20) relative to the prefabricated pile (10), and multiple groups of supports (21) are arranged vertically, and each group of supports (21) is arranged at least two in the transverse direction of the prefabricated support template (20), and the same group of connecting rod group three is installed on the upper and lower groups of supports (21), and the ends of the connecting rod group three and the connecting rod group two (50) are arranged to slide vertically; The support (21) is provided with mounting holes, and the support (21) is mounted on the prefabricated support template (20) by means of bolts passing through the mounting holes. The connecting rod group 3 includes a connecting pipe sleeve (22), which is mounted on a side of the support (21) opposite to the prefabricated pile (10), and a vertical position retaining rod (23) is installed inside the connecting pipe sleeve. The connecting rod group 1 (40) and the connecting rod group 2 (50) are both telescopic rods capable of freely adjusting their lengths, and one end of the connecting rod group 2 (50) is provided with a connecting structure adapted for vertical sliding engagement with the vertical position retaining rod (23); The connection structure includes a mounting plate (51) mounted on the end of the second connecting rod group (50), a guide plate (52) being movably mounted on the mounting plate (51), a through-notch (54) being arranged on the guide plate (52), a mounting groove (53) being arranged on the mounting plate (51), and the mounting groove (53) being suitable for mounting the guide plate (52), a guide groove 1 (55) and a guide groove 2 (56) being arranged on the side wall of the mounting groove (53), a guide pin shaft (57) being mounted in each of the guide groove 1 (55) and the guide groove 2 (56), and both the guide pin shafts (57) being mounted on the side wall of the guide plate (52), a torsion spring being mounted between the guide pin shaft (57) and the guide plate (52), and a spring 1 (58) being mounted in the guide groove 2 (56) for contacting the guide plate (52); When the guide plate (52) is in a free state, the through-slot (54) is in an inclined state and only allows the vertical position holding rod (23) to pass through. When the guide plate (52) is in a horizontal state under the action of the connecting pipe sleeve (22), the connecting pipe sleeve (22) can pass through.

2. The soft foundation ultra-deep pit support structure according to claim 1, characterized in that: The waterproof structure between the prefabricated support templates (20) includes a convex portion (24) and a groove (25) arranged on the side of the prefabricated support template (20), a clamping structure is installed in the groove (25) for clamping the groove on the side of the convex portion (24), and an elastic locking member (26) is installed inside the groove (25) for locking the clamping structure, and a sealing strip is installed between two adjacent groups of prefabricated support templates (20).

3. The soft foundation ultra-deep pit support structure according to claim 2, characterized in that: The clamping structure includes a clamping claw (27), a rotating groove (28), a slide groove (29) and a slide groove (210), wherein the slide groove (29) and the slide groove (210) are arranged in parallel and a slider (211) is installed in the slide groove (29) and the slide groove (210), and the rotating groove (28) is arranged on a side of the slide groove (29) away from the protrusion (24) and one end thereof is connected to the end of the slide groove (29) away from the slide groove (210). The slider (211) is installed on both sides of the clamping claw (27), and a pressing joint is installed on the clamping claw (27) and the pressing joint is suitable for being driven by the end of the protrusion (24) to drive the clamping claw (27) to rotate. A spring 2 (212) is installed between the back side of the clamping claw (27) and the inner wall of the tongue and groove (25). A locking groove (213) adapted to the end of the elastic locking member (26) is arranged on one side of the clamping claw (27) opposite to the inner wall of the tongue and groove (25).

4. The soft foundation ultra-deep pit support structure according to claim 3, characterized in that: A water seepage hole (215) is provided on the outer wall of the prefabricated support template (20), a water through hole (214) communicating with the water seepage hole (215) is provided inside the prefabricated support template (20), and a water guide belt is installed in the water seepage hole (215) and the water through hole (214).

5. The soft foundation ultra-deep pit support structure according to claim 4, characterized in that: A prefabricated tip is installed at the bottom of the prefabricated support template (20) located at the bottom, and the prefabricated tip is pressed into the stabilizing layer (30).

6. A construction method for a soft foundation ultra-deep pit support structure according to claim 5, characterized in that: The construction steps are as follows: Step 1: According to the design requirements of the drawings, the position area lines of the prefabricated piles (10) and the prefabricated support templates (20) are drawn on the soft foundation section, and the prefabricated piles (10) are pressed into the inside of the soft foundation section by the pressing equipment, and the bottom prefabricated tip (11) is pressed into the inside of the stabilization layer (30); Step 2: Install the connecting rod group 1 between two adjacent groups of prefabricated piles (10), and then vertically press-fit the prefabricated support template (20) layer by layer according to the position area line of the prefabricated support template (20). Before pressing each layer of the prefabricated support template (20), install the support (21), and assemble the support (21) through the vertical position holding rod (23) by using the connecting pipe sleeve (22) on the support (21). The vertical position holding rod (23) is slidably matched with the connecting structure on the connecting rod group 2 (50) to ensure the stability of the vertical press-fit of the prefabricated support template (20), until the prefabricated tip on the prefabricated support template (20) is pressed into the stable layer (30); When the prefabricated support formwork (20) is pressed, the vertical position holding rod (23) is in a vertical stable sliding state under the action of the guide plate (52) in an inclined state. When the connecting pipe sleeve (22) acts on the guide plate (52), the guide plate (52) rotates under the action of the two guide pins (57) and moves a small distance to the side away from the connecting pipe sleeve (22). When the guide plate (52) is in a horizontal state under the action of the connecting pipe sleeve (22), the connecting pipe sleeve (22) can pass through the through-notch (54) in a vertical stable manner. After the connecting pipe sleeve (22) passes through the through-notch (54), the guide plate (52) is reset to the initial state under the action of the spring 1 (58) and the torsion spring to allow the vertical position holding rod (23) to slide vertically stably. The prefabricated support template (20) is assembled vertically and horizontally in the support direction, and is connected and assembled through the tongue and groove (25) and the convex part (24). After the end of the convex part (24) enters the tongue and groove (25), it acts on the clamping claw (27) and drives the clamping claw (27) to rotate along the rotation groove (28) to complete the action of clamping the convex part (24). As the convex part (24) continues to enter the tongue and groove (25), the clamping claw (27) and the convex part (24) move together. When the locking groove (213) on the clamping claw (27) moves to a position adapted to the elastic locking member (26), the connection between the convex part (24) and the tongue and groove (25) is completed. At this time, the spring 2 (212) is in a stretched state, and the sealing strip is in a crimped state. Step 3: Excavate the foundation pit and backfill the foundation pit, and remove the prefabricated support template (20) and prefabricated piles (10) by lifting equipment.

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