Open caisson wall cleaning system and open caisson bottom sealing method

Abstract

The invention belongs to the technical field of underground engineering, and discloses an open caisson wall cleaning system and an open caisson bottom sealing method. The open caisson wall cleaning system comprises a drawing rope and a covering film, the drawing rope penetrates through the covering film, the covering film comprises a first area and a second area which are spliced, the end, away from the first area, of the second area is fixed to the upper end of a blade foot, the upper end of the blade foot is the position, close to the blade foot, of an inner well wall of an open caisson, and the second area surrounds and wraps the inner well wall in the circumferential direction. The first area is attached to the second area; the drawing rope drags the covering film to drive the covering film to be folded to a pouring state, in the pouring state, the first area and the second area are attached to the excavation face of the open caisson, the edge of the first area is folded, and a closed pouring face is formed. According to the open caisson wall cleaning system, silt, sediment and other sundries can be prevented from adhering to the inner well wall, so that the bonding quality of the bottom sealing concrete and the inner well wall is improved, meanwhile, the seepage path of underground water is prolonged through the covering film, and the waterproof performance of the bottom sealing is improved.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering, and in particular to a caisson wall cleaning system and a caisson bottom sealing method. Background Art

[0002] A caisson is a common shaft-shaped structure in underground engineering, usually used as the foundation of bridge piers or other structures; the basic principle of its sinking is to utilize the deadweight of the shaft and the friction between the shaft wall and the soil layer, and to dig soil inside the shaft so that the shaft gradually sinks in the soil layer.

[0003] After the caisson is sunk, the bottom of the caisson needs to be sealed to improve the stability and safety of the caisson. Before the bottom is sealed, the inner wall of the wellbore needs to be cleaned to remove the silt sediment and other debris attached to the well wall, so as to improve the bonding quality between the bottom seal concrete and the well wall; the commonly used method for cleaning the well wall is to go down to the bottom of the well manually to clean the well wall, but this method has the problems of low cleaning efficiency and insufficient cleaning effect, and there is a certain danger for the caisson that needs to be cleaned underwater. In addition, when pouring the bottom seal concrete underwater, the initial pouring of concrete will form a large impact force, so that the mud and sand at the bottom of the well are washed up and mixed in the bottom seal concrete, which reduces the strength of the bottom seal concrete and easily forms a seepage path. At present, methods such as throwing gravel layers and placing steel plates at the bottom of the concrete conduit are usually used to avoid the above situation, but the method of throwing gravel is less economical, and placing steel plates is difficult to apply to the situation where the bottom of the caisson is pot-shaped.

[0004] Therefore, it is urgent to design a caisson wall cleaning system to solve the above problems existing in the prior art. Summary of the invention

[0005] The object of the present invention is to provide a caisson wall cleaning system and a caisson bottom sealing method, which can prevent silt sediment from adhering to the inner well wall to improve the bonding quality between the bottom sealing concrete and the inner well wall, and can extend the seepage path between the bottom sealing concrete and the well wall, thereby improving the water-proof effect of the undrained caisson bottom sealing.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] Caisson cleaning system, including:

[0008] Draw cord;

[0009] A covering film, wherein the pull rope is passed through the covering film, and the covering film comprises a first area and a second area spliced ​​along the axial direction of the caisson, wherein one end of the second area away from the first area is fixed to the upper end of the blade foot of the inner well wall, wherein the upper end of the blade foot is a position of the inner well wall of the caisson close to the blade foot, and the second area surrounds and covers the inner well wall along the circumferential direction, and the first area is close to the second area;

[0010] The pull rope pulling the covering film can drive the covering film to be folded to the casting state. In the casting state, the first area and the second area are respectively attached to the excavation surface of the caisson, and the edges of the first area are gathered to form a closed casting surface.

[0011] Preferably, the caisson wall cleaning system further comprises a fixing plug, and a fixing groove is provided on the inner well wall;

[0012] The second region has a fixed end and a free end, the fixed end is away from the first region and is fixedly arranged at the upper end of the blade foot, the free end is connected to the first region, the first region is abutted against the free end along the radial direction of the caisson, the fixing plug abuts against the first region and is inserted into the fixing groove, so that the free end is fixed in the fixing groove.

[0013] Preferably, the caisson wall cleaning system also includes a releasing structure, which includes an airbag and a gas supply channel arranged on the inner well wall, the gas supply channel is connected to the airbag, the airbag is arranged at the bottom of the fixed groove, the gas supply channel is used to pass gas into the airbag, and the airbag is configured to push the fixed plug out of the fixed groove after ventilation and expansion.

[0014] Preferably, the edge of the covering film is provided with inwardly concave teeth, and a rope-threading protrusion is formed between two adjacent inwardly concave teeth, the pull-out rope is passed through the rope-threading protrusion, and the rope-threading protrusion can slide along the pull-out rope.

[0015] Preferably, the caisson wall cleaning system further comprises a fixed pulley, wherein the fixed pulley is arranged on the inner well wall, the pull rope is wound around the fixed pulley and an end of the pull rope extends out of the wellhead.

[0016] Preferably, ventilation holes are provided in the first area.

[0017] The caisson bottom sealing method, using the above-mentioned caisson wall cleaning system, comprises the following steps:

[0018] S1, fixing one end of the second region away from the first region to the upper end of the blade foot, folding the first region so that the first region is attached to the second region, and the second region is attached to the inner well wall;

[0019] S2, excavating the soil layer to sink the caisson to a specified depth;

[0020] S3, pulling the draw rope to fold the covering film to the casting state;

[0021] S4, pouring concrete on the pouring surface.

[0022] Preferably, before pulling the draw rope in step S3, the method further includes:

[0023] The first region is removed from the second region, and an end of the second region close to the first region is removed from the inner well wall.

[0024] Preferably, after pulling the draw rope in step S3, the method further includes:

[0025] Heavy objects are placed into the first area and the second area.

[0026] Preferably, one end of the second region away from the first region is buried in the inner well wall.

[0027] The beneficial effects of the present invention are:

[0028] The caisson wall cleaning system provided by the present invention comprises a pulling rope and a covering film, wherein the pulling rope is passed through the covering film, and the covering film comprises a first area and a second area spliced ​​along the axial direction of the caisson, and the first area is attached to the second area; since one end of the second area is fixed to the upper end of the blade foot of the inner wall of the caisson, and the second area is circumferentially attached to the inner wall of the caisson, it plays a role of isolating the soil layer during the sinking of the caisson, and can effectively prevent silt sediment and other debris from adhering to the inner wall of the caisson, and the covering film can be peeled off from the inner wall of the caisson by the pulling rope, and the bonding quality of the bottom sealing concrete and the inner wall of the caisson can be guaranteed without manual cleaning of the wall, thereby greatly improving the construction efficiency and Construction safety; pulling the covering film by pulling the rope can make the covering film fold over to the casting state. When the covering film is in the casting state, the first area and the second area are respectively attached to the excavation surface of the caisson, and the edges of the first area are gathered to form a closed casting surface. Therefore, when the covering film is pulled by the pulling rope, the first area and the second area can be folded down from the inner well wall and cover the excavation surface, thereby forming a layer of isolation structure, which can block the soil and groundwater under the excavation surface, prevent the soil from being impacted into the bottom seal concrete, resulting in the bottom seal being unstable and leaking, and at the same time extend the seepage path of groundwater, greatly improving the waterproof performance of the caisson bottom seal.

[0029] The method for sealing the bottom of a caisson plays a role in isolating the soil layer by sticking a covering film on the inner well wall and fixing the bottom end of the second area to the upper end of the blade foot of the inner well wall. It can prevent silt sediment and other debris from adhering to the inner well wall during the sinking of the caisson, and the covering film can be peeled off from the inner well wall by pulling a pull rope, without the need to manually go down the well to clean the wall, thereby ensuring the bonding quality of the concrete and the inner well wall when sealing the bottom, saving time and effort and improving construction efficiency. Because pulling the pull rope can fold the covering film to a casting state, the covering film is now detached from the inner well wall and stuck to the excavation surface below the caisson, and the first area and the second area form a closed casting surface, which greatly improves the mud and water isolation performance of the caisson bottom sealing, thereby improving the safety of the caisson use. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of a covering film provided in a specific embodiment of the present invention;

[0031] Figure 2 It is a side view of the caisson after the bottom is sealed provided by a specific embodiment of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the inner well wall of the caisson provided in a specific embodiment of the present invention;

[0033] Figure 4 yes Figure 3 A partial enlarged view of the middle A;

[0034] Figure 5 yes Figure 3 A partial enlarged view of point B in the middle;

[0035] Figure 6 It is a schematic diagram of the edge structure of the covering film.

[0036] In the figure:

[0037] 100-caisson; 110-fixed groove;

[0038] 1-Draw cord;

[0039] 2-covering film; 21-first area; 211-ventilation hole; 22-second area; 23-inner concave tooth opening; 24-rope threading convex part;

[0040] 3-Fixed plug;

[0041] 4-relaxing structure; 41-air delivery channel; 42-air bag;

[0042] 5-Fixed pulley. DETAILED DESCRIPTION

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0044] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0046] In the description of this embodiment, the terms "upper", "lower", "right", "left" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0047] like Figures 1 to 3As shown, the present invention provides a caisson wall cleaning system, which includes a pull rope 1 and a covering film 2, the pull rope 1 is inserted into the covering film 2, the covering film 2 includes a first area 21 and a second area 22 spliced ​​along the axial direction of the caisson 100, the end of the second area 22 away from the first area 21 is fixed to the upper end of the blade foot of the inner well wall, the upper end of the blade foot is the position of the inner well wall of the caisson 100 close to the blade foot, the second area 22 is circumferentially wrapped around the inner well wall, and the first area 21 is circumferentially attached to the second area 22; the pull rope 1 pulls the covering film 2 to drive the covering film 2 to be folded to a casting state, in which the first area 21 and the second area 22 are respectively attached to the excavation surface of the caisson 100, and the edge of the first area 21 is gathered to form a closed casting surface.

[0048] In this embodiment, since one end of the second area 22 is fixed to the upper end of the blade foot of the inner wall of the caisson 100, and the second area 22 is circumferentially attached to the inner wall, during the sinking of the caisson 100, it is possible to effectively prevent debris such as silt sediment from adhering to the inner wall, and the covering film 2 can be folded to the casting state by pulling the rope 1 to peel off the covering film 2 from the inner wall, thereby cleaning the debris adhering to the covering film 2 onto the excavation surface, and the bonding quality of the bottom sealing concrete and the inner wall can be ensured without cleaning the wall before sealing the bottom, thereby greatly improving the construction efficiency and construction safety. Safety; Pulling the covering film 2 with the pull rope 1 can cause the covering film 2 to be folded to the casting state. When the covering film 2 is in the casting state, the first area 21 and the second area 22 are respectively attached to the excavation surface of the caisson 100, and the edge of the first area 21 is gathered to form a closed casting surface. Therefore, when the pull rope 1 pulls the covering film, the first area 21 and the second area 22 can be folded down from the inner well wall and covered on the excavation surface, thereby forming a layer of isolation structure, which can block the soil and groundwater below the excavation surface, greatly improving the mud and water isolation performance of the caisson bottom seal. Specifically, the covering film 2 is a high-performance polymer film made of polyetheretherketone, which has the advantages of high temperature resistance, corrosion resistance, hydrolysis resistance and flame retardancy. It can stably cover the excavation surface at the bottom of the caisson 100 and isolate groundwater. At the same time, the covering film 2 also has a certain flexibility, and can be folded and gathered under the pull of the pull rope 1, thereby forming a closed casting surface.

[0049] The shape of the covering film 2 can be set according to actual needs, as long as it can cover the inner well wall along the circumferential direction and form a closed casting surface when in the casting state. Exemplarily, the second area 22 is a rectangle, the long side of the rectangle is equal to the inner perimeter of the cross section of the caisson 100, the short side length of the rectangle is not less than the casting height of the bottom concrete, the first area 21 is an enclosed arc, and the straight side of the first area 21 is spliced ​​with the second area 22; the second area 22 has a free end and a fixed end, the fixed end is the bottom of the second area 22 away from the first area 21, the free end is the top of the second area 22 close to the first area 21, the fixed end is fixedly connected to the upper end of the blade foot of the inner well wall, the upper end of the blade foot is located at the inner well wall near the blade foot, the free end is detachably connected to the inner well wall, and the axial distance between the free end and the fixed end along the caisson 100 is the short side length of the second area 22. Before the caisson 100 is sunk, the staff folds the second area 22 around the axis of the caisson 100 and places the folded second area 22 against the inner well wall, with the two short sides of the second area 22 connected. Then the staff folds the first area 21 along the axial direction of the caisson 100 to make it rest against the free end of the second area 22. At this time, the covering film 2 is not in a casting state, and the second area 22 is coated on the inner well wall to ensure that the silt sediment is isolated by the covering film 2. When the caisson 100 sinks to the specified depth, the staff pulls the draw rope 1. Since the covering film 2 is a flexible membrane structure, under the pulling of the draw rope 1, The free ends of the first area 21 and the second area 22 detach from the inner well wall and flip downward, and pass through the plane where the fixed end of the second area 22 is located, until they are in contact with the excavation surface below the caisson 100. At this time, the covering film 2 is in a casting state. During this process, the first area 21 is flipped from above the fixed end to below the fixed end, and the free end of the second area 22 is also flipped from above the fixed end to below the fixed end under the drive of the first area 21; when the covering film 2 is in a casting state, the first area 21 and the second area 22 are both below the plane where the fixed end is located.

[0050] Furthermore, if Figures 2 to 4 As shown, the caisson wall cleaning system also includes a fixing plug 3, and a fixing groove 110 is opened on the inner wall of the caisson; the second area 22 has a fixed end and a free end, the fixed end is away from the first area 21 and is fixedly arranged at the upper end of the blade foot, and the free end is connected to the first area 21, and the first area 21 is in contact with the free end along the radial direction of the caisson 100, and the fixing plug 3 is in contact with the first area 21 and inserted into the fixing groove 110, so that the free end is fixed to the fixing groove 110; specifically, before sinking the caisson 100, the staff fixes the fixed end at the upper end of the blade foot of the inner wall of the caisson, and folds the first area 21, so that the first area 21 is in contact with the second area 22 along the radial direction of the caisson 100, and then uses the fixing plug 3 to fix the first area 21 and the free end in the fixing groove 110.

[0051] Specifically, Figures 2 to 4 As shown, the caisson wall cleaning system also includes a loosening structure 4, which includes an air bag 42 and a gas supply channel 41 arranged on the inner wall of the caisson, the gas supply channel 41 is connected to the air bag 42, the air bag 42 is arranged at the bottom of the fixed groove 110, the gas supply channel 41 is used to pass gas into the air bag 42, and the air bag 42 is configured to push the fixed plug 3 out of the fixed groove 110 after ventilation and expansion; due to the provision of the loosening structure 4, the staff does not need to go down to the caisson 100 to remove the fixed plug 3, and the fixed plug 3 can be removed from the fixed groove 110 by delivering gas to the gas supply channel 41 on the ground, which is convenient to operate and saves time and effort.

[0052] Specifically, the gas delivery channel 41 includes a gas delivery pipe and a ventilation cavity, the ventilation cavity is opened in the inner well wall, one end of the gas delivery pipe is connected to the ventilation cavity, and the other end of the gas delivery pipe extends out of the ground along the axial direction of the vertical caisson 100 and is connected to a blower. It can be understood that the ventilation cavity is reserved when the caisson 100 is manufactured.

[0053] Specifically, Figure 1 and Figure 6 As shown, the edge of the covering film 2 is provided with an inwardly concave tooth opening 23, and a rope-threading protrusion 24 is formed between two adjacent inwardly concave tooth openings 23. The pull rope 1 is passed through the rope-threading protrusion 24, and the rope-threading protrusion 24 can slide along the pull rope 1. The inwardly concave tooth opening 23 provides an escape space for the edge of the first area 21 to be gathered and aggregated, thereby ensuring that the covering film 2 can be smoothly tightened to form a closed casting surface.

[0054] Furthermore, if Figure 2 , Figure 3 as well as Figure 5 As shown, the caisson wall cleaning system also includes a fixed pulley 5, which is arranged on the inner well wall, and the pull rope 1 is wound around the fixed pulley 5 and the end of the pull rope 1 extends out of the wellhead. The fixed pulley 5 can change the direction of the force, so the staff can pull the pull rope 1 on the bottom surface at the wellhead to pull the covering film 2; specifically, the straight edge of the first area 21 is spliced ​​on a long side of the second area 22, and the curved edge of the first area 21 and the two short sides of the second area 22 connected thereto are both provided with inner concave teeth 23 and rope threading protrusions 24, and the pull rope 1 passes through the first short side, the second short side, and the second short side of the second area 22 in sequence. The curved side of the first area 21 and the second short side of the second area 22 form two movable rope ends at the fixed end of the second area 22, and the two rope ends are both wound around the fixed pulley 5 and extend out of the wellhead; when the caisson 100 sinks to the specified depth, the staff pulls the two rope ends of the pull rope 1 vertically upward, and the pull rope 1 forms a vertical downward pulling force on the curved side of the first area 21 through the fixed pulley 5, thereby driving the first area 21 to flip downward, and then driving the second area 22 to flip downward as well, until the first area 21 and the second area 22 are respectively attached to the excavation surface and form a pot-bottom-shaped casting surface.

[0055] Furthermore, if Figure 1 As shown, air holes 211 are provided on the first area 21. When the covering film 2 is pulled away from the inner well wall by the pull rope 1 and pressed downward against the excavation surface, water between the covering film 2 and the excavation surface will be discharged through the air holes 211, thereby accelerating the adhesion of the covering film 2 to the excavation surface and improving the degree of adhesion between the covering film 2 and the excavation surface.

[0056] This embodiment also provides a caisson bottom sealing method, using the above-mentioned caisson wall cleaning system, including the following steps:

[0057] S1. Fix the end of the second area 22 away from the first area 21 to the upper end of the blade foot, fold the first area 21 so that the first area 21 is attached to the second area 22, and the second area 22 is attached to the inner well wall; before the caisson 100 sinks, the staff first attaches the second area 22 to the inner well wall, and fixes the fixed end of the second area 22 to the upper end of the blade foot, then folds the first area 21 downward and attaches it to the free end of the second area 22 along the radial direction of the caisson 100, and then the staff uses the fixing plug 3 to rest on the folded first area 21, and sets the free end plugs of the first area 21 and the second area 22 in the fixing groove 110.

[0058] S2. Excavate the soil layer to sink the caisson 100 to a specified depth. Since the second area 22 is attached to the inner well wall and the bottom of the second area 22 is fixed to the upper end of the blade foot, during the sinking of the caisson 100, the covering film 2 can isolate the inner well wall from the soil layer, thereby preventing debris such as silt and sediment from adhering to the inner well wall.

[0059] S3. Pull the pull rope 1 to fold the covering film 2 to the casting state; after the caisson 100 sinks to the specified depth, the staff pulls the pull rope 1 on the ground. Since the pull rope 1 is inserted into the covering film 2, pulling the pull rope 1 upward can drive the covering film 2 to shrink and bring its edges together, thereby forming a closed casting surface on the excavation surface, further improving the mud and water-proof performance of the bottom seal.

[0060] S4. Pour concrete on the casting surface.

[0061] By using the caisson bottom sealing method, a covering film 2 is pasted on the inner well wall and the bottom end of the second area 22 is fixed to the upper end of the blade foot of the inner well wall, thereby isolating the soil layer, and preventing silt sediment and other debris from adhering to the inner well wall during the sinking of the caisson 100, and the covering film 2 can be peeled off from the inner well wall by pulling the pull rope 1, without the need for manual cleaning of the wall, thereby ensuring the bonding quality of the concrete and the inner well wall when sealing the bottom, saving time and effort and improving construction efficiency; because pulling the pull rope 1 can make the covering film 2 fold over to the casting state, at this time the covering film 2 is separated from the inner well wall and pasted on the excavation surface below the caisson 100, and the first area 21 and the second area 22 form a closed casting surface, which greatly improves the mud and water isolation performance of the caisson bottom sealing, thereby improving the safety of the use of the caisson 100.

[0062] Furthermore, before pulling the draw rope 1 in step S3, the step also includes: removing the first area 21 from the second area 22, and removing the end of the second area 22 close to the first area 21 from the inner well wall, thereby reducing the pulling resistance of the draw rope 1 and preventing the draw rope 1 or the covering film 2 from being damaged due to excessive pulling force.

[0063] Specifically, a release structure 4 is provided on the inner well wall. Before pulling the draw rope 1, the staff uses the release structure 4 to remove the free end of the second area 22 and the fixed plug 3 of the first area 21 from the fixed groove 110. At this time, the free ends of the first area 21 and the second area 22 are unlocked, which is convenient for pulling the draw rope 1 and folding downward. Exemplarily, the release structure 4 includes an air supply channel 41 and an air bag 42. The air supply channel 41 is provided on the inner well wall, and the air bag 42 is provided at the bottom of the fixed groove 110. The air supply channel 41 is connected to the air bag 42. When it is necessary to remove the fixed plug 3 from the fixed groove 110, the staff on the ground passes gas into the air bag 42 through the air supply channel 41 to expand the air bag 42 and push the fixed plug 3 out of the fixed groove 110, thereby releasing the fixed connection between the free ends of the first area 21 and the second area 22 and the inner well wall.

[0064] Furthermore, after pulling the pull rope 1 in step S3, it also includes: throwing heavy objects into the first area 21 and the second area 22, the heavy objects can cover the first area 21 and the second area 22, so that the first area 21 and the second area 22 quickly fall onto the excavation surface, thereby accelerating the fitting of the covering film 2 to the excavation surface.

[0065] Furthermore, in order to improve the connection strength between the fixed end of the second region 22 and the caisson 100, one end of the second region 22 away from the first region 21 is buried in the inner well wall; specifically, when making the caisson 100, the fixed end of the second region 22 is pre-placed in the mold for making the caisson 100, and is aligned with the upper end of the blade foot of the inner well wall, and then the caisson 100 is cast into shape.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Caisson wall cleaning system, characterized in that: include: Draw cord (1); A covering film (2), wherein the pull rope (1) is passed through the covering film (2), and the covering film (2) comprises a first region (21) and a second region (22) which are connected to each other along the axial direction of the caisson (100), wherein one end of the second region (22) which is away from the first region (21) is fixed to the upper end of the blade foot, and the upper end of the blade foot is a position of the inner well wall of the caisson (100) close to the blade foot, and the second region (22) is circumferentially wrapped around the inner well wall, and the first region (21) is in contact with the second region (22); The pull rope (1) pulls the covering film (2) to drive the covering film (2) to be folded to a casting state. In the casting state, the first area (21) and the second area (22) are respectively attached to the excavation surface of the caisson (100), and the edge of the first area (21) is gathered to form a closed casting surface.

2. The caisson wall cleaning system according to claim 1, characterized in that: The caisson wall cleaning system also includes a fixing plug (3), and a fixing groove (110) is provided on the inner well wall; The second region (22) has a fixed end and a free end, the fixed end is away from the first region (21) and is fixedly arranged at the upper end of the blade foot, the free end is connected to the first region (21), the first region (21) is in abutment with the free end along the radial direction of the caisson (100), the fixing plug (3) is in abutment with the first region (21) and is inserted into the fixing groove (110), so that the free end is fixed to the fixing groove (110).

3. The caisson wall cleaning system according to claim 2, characterized in that: The caisson wall cleaning system further comprises a release structure (4), the release structure (4) comprising an air bag (42) and an air supply channel (41) arranged on the inner well wall, the air supply channel (41) being connected to the air bag (42), the air bag (42) being arranged at the bottom of the fixing groove (110), the air supply channel (41) being used for passing gas into the air bag (42), and the air bag (42) being configured to push the fixing plug (3) out of the fixing groove (110) after being ventilated and expanded.

4. The caisson wall cleaning system according to claim 1, characterized in that: The edge of the covering film (2) is provided with an inwardly concave tooth opening (23), a rope-threading protrusion (24) is formed between two adjacent inwardly concave tooth openings (23), the pull-out rope (1) is threaded through the rope-threading protrusion (24), and the rope-threading protrusion (24) can slide along the pull-out rope (1).

5. The caisson wall cleaning system according to claim 4, characterized in that: The caisson wall cleaning system further comprises a fixed pulley (5), wherein the fixed pulley (5) is arranged on the inner well wall, the pull rope (1) is wound around the fixed pulley (5), and the end of the pull rope (1) extends out of the well mouth.

6. The caisson wall cleaning system according to claim 1, characterized in that: The first area (21) is provided with a ventilation hole (211).

7. A method for sealing the bottom of a caisson, using the caisson wall cleaning system according to any one of claims 1 to 6, comprising the following steps: S1, fixing one end of the second area (22) away from the first area (21) to the upper end of the blade foot, folding the first area (21) so that the first area (21) is attached to the second area (22), and attaching the second area (22) to the inner well wall; S2, excavating the soil layer to sink the caisson (100) to a specified depth; S3, pulling the draw rope (1) to fold the covering film (2) to the casting state; S4, pouring concrete on the pouring surface.

8. The method for sealing the bottom of a caisson according to claim 7, characterized in that: Before pulling the draw rope (1) in step S3, the method further includes: The first region (21) is removed from the second region (22), and the end of the second region (22) close to the first region (21) is removed from the inner well wall.

9. The method for sealing the bottom of a caisson according to claim 7, characterized in that: After pulling the draw cord (1) in step S3, the method further includes: Heavy objects are placed into the first area (21) and the second area (22).

10. The method for sealing the bottom of a caisson according to claim 7, characterized in that: One end of the second area (22) away from the first area (21) is buried in the inner well wall.

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