A caisson with a waterproof structure of a non-welding water-stop steel plate and a construction method thereof

Abstract

The present invention relates to a caisson with a waterproof structure of a non-welding water-stop steel plate and a construction method thereof, comprising the following steps: excavation of a foundation pit, laying of a sand cushion layer, and casting of a blade foot on the sand cushion layer; tying steel bars and erecting a formwork for the caisson in the foundation pit; inserting the ends of the two water-stop steel plates into the left connector and the right connector respectively, and after the non-welding connection structure is unfolded around the rotation axis to match the rotation angle, fixing the angle by a spring and a steel rod; installing a fixing device, and adjusting the height and position of the water-stop steel plate by a position-adjusting bolt; and casting the lower segment in the adjacent caisson segment. The beneficial effects of the present invention are as follows: both the fixing device and the non-welding connection structure can be split into an upper and lower part, so after segmented casting, the fixing device and the upper half of the non-welding connection structure can be dismantled and recycled, which greatly improves the utilization rate of materials and reduces construction costs.

Description

Technical Field

[0001] The present invention belongs to the field of caisson water stopping, and in particular relates to a caisson with a welding-free water stopping steel plate waterproof structure and a construction method thereof. Background Art

[0002] A caisson is a shaft-like structure constructed by excavating soil within it, allowing it to sink to the designed elevation under its own gravity, overcoming frictional resistance against the shaft walls, and then be sealed with concrete. Caissons offer large cross-sectional dimensions, high bearing capacity, and usable internal space, making them suitable for constructing underground projects at considerable depths. During the design and construction of caisson structures, the joining of the shaft walls and the connection to the shaft floor are both secondary pouring processes. Due to the presence of construction joints, waterproofing measures are particularly important.

[0003] In the prior art, the typical waterproofing measure for well walls is to install welded waterstop steel plates at the joints of the well walls. However, due to the inclined structure formed by the bends at the upper and lower ends of the waterstop steel plates, gaps are easily left between the inclined portions of adjacent waterstop steel plates at corners, making repair welding difficult. Furthermore, the welding angle is difficult to control. Furthermore, since the waterstop steel plates are relatively thin, excessive welding can easily penetrate the waterstop steel plates, affecting the waterstop effect. Furthermore, the waterstop steel plates are typically welded to the steel bars of the caisson wall, and the quality of the welding significantly affects the performance of the waterstop steel plates. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a caisson with a waterproof structure of a non-welding water-stop steel plate and a construction method thereof.

[0005] This caisson with a non-welding water-stop steel plate waterproof structure has water-stop steel plates installed at the construction joints of the upper and lower adjacent caisson segments through a fixing device, and two adjacent water-stop steel plates at the corner are connected to each other through a non-welding connection structure; a bottom plate is embedded in a groove above the blade foot of the caisson;

[0006] The welding-free connection structure includes a left connector and a right connector. Each of the left connector and the right connector includes an upper and lower part connected by a mortise and tenon joint. The left connector and the right connector are connected by a rotating shaft. The ends of the two water-stop steel plates at the corners are respectively inserted into the left connector and the right connector. A spring and a steel rod are provided on the back of the welding-free connection structure to fix the expansion angle of the left connector and the right connector.

[0007] The fixing device includes an upper connecting piece, a lower connecting piece and a steel bar clamp. The back of the upper connecting piece is rotatably connected to a position adjustment bolt, and the position adjustment bolt is threadedly connected to the connecting piece. The top of the connecting piece is also rotatably connected to a position adjustment bolt, and the steel bar clamp is threadedly connected to the position adjustment bolt above the connecting piece. The steel bar clamp is clamped on the steel bar of the upper segment in the adjacent caisson segment.

[0008] Preferably, the flanges of the upper and lower parts of the left connecting member and the right connecting member are provided with grooves corresponding to the upper and lower ends of the waterstop steel plate, and the sides where the left connecting member and the right connecting member are connected to each other are alternately provided with shaft cylinders. When the left connecting member and the right connecting member are connected, the rotating shaft is inserted into the shaft cylinders that are connected in sequence, and the upper and lower ends of the rotating shaft are respectively connected to the outside of the shaft cylinder by threads with nuts and cover nuts.

[0009] Preferably, the left connecting member includes an upper left connecting member and a lower left connecting member, and the right connecting member includes an upper right connecting member and a lower right connecting member. Shaft tubes are alternately provided at the connection between the upper left connecting member and the upper right connecting member, and the length of the shaft tubes after being connected is equal to the height of the upper left connecting member and the upper right connecting member; shaft tubes are also alternately provided at the connection between the lower left connecting member and the lower right connecting member, and the length of the shaft tubes after being connected is equal to the height of the lower left connecting member and the lower right connecting member.

[0010] Preferably, the backs of the upper left connecting piece and the upper right connecting piece are provided with hanging rings and steel rod holes, the two ends of the spring are respectively connected to the hanging rings of the upper left connecting piece and the upper right connecting piece, and the two ends of the steel rod are respectively inserted into the steel rod holes of the upper left connecting piece and the upper right connecting piece.

[0011] Preferably, an adjusting bolt connecting hole is provided on the back of the upper connecting piece, and the connecting piece is provided with a horizontal position adjusting hole. One end of the position adjusting bolt is rotatably provided in the adjusting bolt connecting hole, and the other end is threaded through the horizontal position adjusting hole; an adjusting bolt connecting hole is also provided on the top of the connecting piece, and a position adjusting bolt is rotatably connected to the adjusting bolt connecting hole, and the steel bar clamp is connected to the position adjusting bolt through the vertical position adjusting hole.

[0012] Preferably, the steel bar clamp includes a symmetrical two-petal opening and closing structure, which is connected by hinges and closures, and the opening and closing surfaces are parallel to the transverse steel bars in the caisson segment. The two-petal opening and closing structures are respectively provided with semicircular grooves on the opening and closing surfaces. When the steel bar clamp is closed, the two semicircular grooves form vertical steel bar connection holes, and are sleeved on the vertical steel bars of the upper segment in the adjacent caisson segment. The bottom of the steel bar clamp is supported on the transverse steel bars of the upper segment in the adjacent caisson segment through semicircular grooves.

[0013] Preferably, a groove is provided on the inner wall of the caisson above the blade foot, and several layers of trapezoidal annular grooves are distributed on the groove wall. An annular waterstop is provided at the bottom of each layer of trapezoidal annular grooves, and several layers of protrusion structures matching the trapezoidal annular grooves are provided on the edge of the bottom plate. The protrusions are embedded in the trapezoidal annular grooves, and the lower surface of the protrusions fits the annular waterstop; a waterproof membrane is provided between the bottom plate and the bottom seal of the caisson, and the edge of the waterproof membrane is fixed to the bottom of the groove by a clamping ring.

[0014] The construction method of the caisson with a waterproof structure of a non-welding water-stop steel plate comprises the following steps:

[0015] Step 1: Excavate the foundation pit, lay the sand cushion layer, and cast the blade foot on the sand cushion layer;

[0016] Step 2: Tie steel bars and erect formwork for the caisson in the foundation pit;

[0017] Step 3: Assemble the welding-free connection structure. Insert the ends of the two water-stop steel plates into the left and right connectors respectively. After the welding-free connection structure is unfolded around the rotation axis to match the rotation angle, the angle is fixed by springs and steel rods.

[0018] A fixing device is installed in the middle section of the waterstop steel plate. The steel bar clamp is clamped on the steel bar of the upper middle section of the adjacent caisson segment. The height and position of the waterstop steel plate are adjusted by the position adjustment bolts so that the lower end of the waterstop steel plate extends into the casting range of the lower middle section of the adjacent caisson segment.

[0019] Step 4: Pour the lower segment of the adjacent caisson segment. When the concrete reaches a certain strength, remove the steel clamp and the upper connector in the fixing device, pull out the rotating shaft, remove the upper half of the left connector and the right connector in the welding-free connection structure, and fill with waterproof material.

[0020] Preferably, step 4 is followed by step 5, and step 5 specifically comprises continuing to simultaneously carry out the installation of the water-stop steel plate and the segmented pouring and sinking of the caisson, pouring the upper end of the water-stop steel plate exposed after the last pouring into the caisson segment, and pouring the lower end of the new water-stop steel plate at the top of the caisson stage; repeating steps 2 to 5 until all segments of the caisson are poured.

[0021] Preferably, the bottom of the caisson is sealed after the concrete is poured in sections, and then the waterproof membrane is fixed to the bottom of the groove above the blade foot by a clamping ring, and several layers of annular waterstops are set in the groove above the waterproof membrane and embedded in the bottom plate.

[0022] The beneficial effects of the present invention are:

[0023] 1) The fixing device and the welding-free connection structure are used to fix the waterstop steel plate and connect it at the corners, respectively, without damaging the waterstop steel plate. At the same time, a large amount of welding work is saved, ensuring that the waterproof quality of the waterstop steel plate is not damaged by electric welding, saving construction time; and the fixing device is fixed on the steel bars of the upper section in the adjacent caisson sections. The fixing device and the welding-free connection structure can be split into two parts, upper and lower. Therefore, after the segmented casting, the fixing device and the upper half of the welding-free connection structure can be dismantled and recycled, greatly improving the utilization rate of materials and reducing construction costs.

[0024] 2) The height and position of the waterstop steel plate are adjusted by two mutually perpendicular position adjustment bolts in the fixing device, which is convenient for improving the installation accuracy of the waterstop steel plate and improving the waterstop effect; the left connecting part and the right connecting part in the welding-free connection structure are connected by a rotating shaft to form a whole that can be unfolded around the rotating shaft. The rotating shaft also plays the role of connecting and providing a rotation axis. The back of the welding-free connection structure is fixed by springs and steel rods to achieve the expansion angle. After pulling out the rotating shaft, the upper and lower parts of the left connecting part and the right connecting part can be separated by translation, which is convenient for disassembly and recycling; after the rotating shaft is recovered, it is filled with waterproof material, which has good sealing and good waterstop effect.

[0025] 3) Multiple layers of closed annular grooves are opened in the grooves, and annular waterstop strips are laid in the annular grooves, which are equivalent to the sealing rings of flanges or threads, and play the role of fastening and sealing the bottom plate and the cylinder wall; and the concave-convex connection structure interrupts the leakage and seepage channel of the original straight construction joint, increases the effective contact area length of the construction joint, and has a significant water-stopping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the overall front view of the welding-free connection structure;

[0027] Figure 2 This is a schematic diagram of the overall back side of the solder-free connection structure;

[0028] Figure 3 It is a schematic diagram of the welding-free connection structure;

[0029] Figure 4 This is a schematic diagram of a welding-free connection structure connector;

[0030] Figure 5 It is an overall schematic diagram of the fixing device;

[0031] Figure 6 It is a schematic diagram of the steel bar clamp;

[0032] Figure 7 is a schematic diagram of the connector;

[0033] Figure 8 Schematic diagram of the upper connector;

[0034] Figure 9 This is a large-scale drawing of the water-stop steel plate installed at the construction joint;

[0035] Figure 10 It is a schematic diagram of the base plate waterproof structure.

[0036] In the figure: waterstop steel plate 1, left connecting piece 2, right connecting piece 3, rotating shaft 4, spring 5, steel rod 6, upper left connecting piece 2-1, lower left connecting piece 2-2, upper right connecting piece 3-1, lower right connecting piece 3-2, cap nut 7, nut 8, lifting ring 9, steel rod hole 10, upper connecting piece 11, lower connecting piece 12, position adjusting bolt 13, connecting piece 14, horizontal position adjusting hole 15, steel bar clamp 16, vertical position adjusting hole 17, steel bar 18, connecting steel bar connecting hole 19, hinge 20, closing piece 21, adjusting bolt connecting hole 22, blade foot 23, trapezoidal ring-mounted slot 24, annular waterstop 25, bottom plate 26, waterproof membrane 27, and retaining ring 28. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, it is possible for a person skilled in the art to make various modifications to the present invention, and such improvements and modifications fall within the scope of the claims of the present invention.

[0038] Example 1

[0039] As an example, Figures 1 to 9 As shown, this caisson with a welding-free waterstop steel plate waterproof structure has a waterstop steel plate 1 installed at the construction joint of the upper and lower adjacent caisson segments through a fixing device. The waterstop steel plate 1 is a 3mm thick galvanized waterstop steel plate with an inclined structure formed by bending the upper and lower ends, which has a waterproof function; the two adjacent waterstop steel plates 1 at the corner are connected to each other by a welding-free connection structure;

[0040] The welding-free connection structure includes a left connecting part 2 and a right connecting part 3. The left connecting part 2 and the right connecting part 3 both include an upper and lower part connected by mortise and tenon joints. The left connecting part 2 includes an upper left connecting part 2-1 and a lower left connecting part 2-2. The right connecting part 3 includes an upper right connecting part 3-1 and a lower right connecting part 3-2. The flanges of the upper left connecting part 2-1 and the lower left connecting part 2-2, and the upper right connecting part 3-1 and the lower right connecting part 3-2 are all provided with card grooves corresponding to the upper and lower ends of the waterstop steel plate 1.

[0041] The left connecting part 2 and the right connecting part 3 are connected by a rotating shaft 4. The ends of the two waterstop steel plates 1 at the corners are respectively inserted into the left connecting part 2 and the right connecting part 3 to realize the connection of the two waterstop steel plates 1. The left connecting part 2 and the right connecting part 3 can rotate around the rotating shaft 4 to realize the angle adjustment of the two waterstop steel plates. A spring 5 and a steel rod 6 are provided on the back of the welding-free connection structure to fix the expansion angle of the left connecting part 2 and the right connecting part 3.

[0042] The upper left and upper right connecting members 2-1 and 3-1 are of equal height and are each less than half the height of the left and right connecting members 2 and 3. Axle cylinders are interlaced at the connection between the upper left and upper right connecting members 2-1 and 3-1, and their length after connection is equal to the height of the upper left and upper right connecting members 2-1 and 3-1. Axle cylinders are also interlaced at the connection between the lower left and lower right connecting members 2-2 and 3-2, and their length after connection is equal to the height of the lower left and lower right connecting members 2-2 and 3-2. When the left and right connecting members 2 and 3 are connected, the rotating shaft 4 is inserted into the interlaced shaft cylinders. A nut 8 and a cap nut 7 are threadedly connected to the outer ends of the shaft cylinders to secure the rotating shaft 4, the left and right connecting members 2, and 3.

[0043] The backs of the upper left connecting piece 2-1 and the upper right connecting piece 3-1 are both provided with a lifting ring 9 and a steel rod hole 10. The two ends of the spring 5 are respectively connected to the lifting rings 9 of the upper left connecting piece 2-1 and the upper right connecting piece 3-1 to prevent the angle between the waterstop steel plates 1 from becoming larger; the two ends of the steel rod 6 are respectively inserted into the steel rod holes 10 of the upper left connecting piece 2-1 and the upper right connecting piece 3-1 to prevent the angle between the waterstop steel plates 1 from becoming smaller.

[0044] The fixing device includes an upper connecting member 11, a lower connecting member 12 and a steel bar clamp 16. The upper connecting member 11 and the lower connecting member 12 are connected by a mortise and tenon structure. An adjusting bolt connecting hole 22 is provided on the back of the upper connecting member 11, which is a countersunk hole; the connecting member 14 is provided with a horizontal position adjustment hole 15, one end of the position adjustment bolt 13 is rotatably arranged in the adjusting bolt connecting hole 22, and the other end is threaded through the horizontal position adjustment hole 15; when the position adjustment bolt 13 rotates, it pushes the upper connecting member 11 to adjust the horizontal position of the waterstop steel plate 1. Since the position adjustment bolt 13 does not penetrate the upper connecting member 11 and rotates in the adjusting bolt connecting hole 22, it will not affect the waterstop effect of the waterstop steel plate 1, and it also ensures that the waterstop steel plate 1 will not rotate with the rotation of the position adjustment bolt 13.

[0045] The top of the connector 14 is also provided with an adjusting bolt connection hole 22, which is also a countersunk hole. One end of another position adjusting bolt 13 is rotatably connected to the adjusting bolt connection hole 22.

[0046] The steel bar clamp 16 includes a symmetrical two-petal opening and closing structure, which is connected by a hinge 20 and a closure 21. The opening and closing surface is parallel to the horizontal steel bars 18 in the caisson segment. The two-petal opening and closing structure is provided with semicircular grooves on the opening and closing surface. When the steel bar clamp 16 is closed, the two semicircular grooves form a circular vertical steel bar connection hole 19. The vertical steel bar connection hole 19 is sleeved on the vertical steel bar 18 of the upper segment in the adjacent caisson segment. The bottom of the steel bar clamp 16 is supported on the horizontal steel bar 18 of the upper segment in the adjacent caisson segment through a semicircular groove.

[0047] In the symmetrical two-petal opening and closing structure, the petal close to the waterstop steel plate 1 is provided with an extension end, and the end of the extension end is provided with a vertical position adjustment hole 17. The position adjustment bolt 13 rotatably connected to the top of the connecting part 14 passes through the vertical position adjustment hole 17. When the position adjustment bolt 13 at the top of the connecting part 14 rotates, since the steel bar clamp 16 is fixed on the steel bar 18, the connecting part 14 at the lower end of the position adjustment bolt 13 drives the upper connecting part 11 and the waterstop steel plate 1 to move up and down, thereby adjusting the vertical position of the waterstop steel plate 1.

[0048] Example 2

[0049] As another embodiment, this embodiment 2 proposes a more specific caisson with a welding-free water-stop steel plate waterproof structure based on the embodiment 1, specifically, a bottom plate waterproof structure is provided at the bottom of the caisson.

[0050] A groove is provided on the inner wall of the caisson above the blade foot 23, and several layers of trapezoidal annular grooves 24 are distributed on the groove wall. An annular waterstop 25 is provided at the bottom of each layer of trapezoidal annular groove 24, and several layers of protrusion structures matching the trapezoidal annular groove 24 are provided on the edge of the bottom plate 26. The protrusions are embedded in the trapezoidal annular groove 24, and the lower surface of the protrusions fits the annular waterstop 25; a waterproof membrane 27 is provided between the bottom plate 26 and the bottom seal of the caisson, and the edge of the waterproof membrane 27 is fixed to the bottom of the groove by a clamping ring 28.

[0051] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0052] Example 3

[0053] As another embodiment, the third embodiment proposes a construction method for a caisson with a waterproof structure of a non-welded water-stop steel plate, comprising the following steps:

[0054] Step 1: excavate the foundation pit, lay a sand cushion layer, and cast the blade foot 23 on the sand cushion layer; specifically:

[0055] To ensure the accuracy of the surveying and positioning of the engineering structure, total stations and levels were used for surveying, setting out, and verification. Before construction, leveling points and coordinate points were re-surveyed, and leveling points were placed in appropriate locations to facilitate construction measurement. An aerial triangulation control network was established, and polar coordinate measurement methods were used for positioning and setting out.

[0056] The caisson structure will be laid out according to the design coordinates, with the blade foot and bottom beam centerline determined. The sidewalls will then be laid out based on the centerline, using a black marker to highlight the edges. The structural dimensions and diagonal dimensions will be checked to ensure they meet the requirements. Once confirmed, the next construction step will be carried out.

[0057] The location of the foundation pit is determined according to the coordinates in the design drawings. Following the caisson axis, control piles and center piles are placed on the ground. The planar dimensions of the foundation pit bottom are equal to the width of the blade foot sand cushion. Based on site conditions, the surface is cleared and excavated at the caisson location. A 1.5m or 2m thick sand cushion is then replaced at the bottom of the foundation pit. After the foundation pit is excavated, a fixed guardrail is installed around the perimeter for protection.

[0058] After acceptance, the sand cushion layer shall be laid in time. In order to ensure the quality of the sand cushion layer, coarse sand shall be used for the sand cushion layer, and it shall be laid in layers of 30 cm each. It shall be sprinkled at a moisture content of 15% and compacted with a flat vibrator. The compaction coefficient is 90%. Before laying the second layer, the lower layer must meet the requirements before the lower layer can be laid.

[0059] When pouring the plain concrete cushion layer of the caisson blade foot on the sand cushion layer, the formwork, pouring and maintenance should be carried out according to the requirements. The elevation of the concrete surface layer must be accurate, and it must be leveled and re-measured by measurement. The relative height difference shall not be greater than ±3mm.

[0060] Step 2: tying steel bars 18 and erecting formwork for the caisson in the foundation pit;

[0061] The order of erecting the inner and outer formwork is, in principle, to erect the inner formwork first and then the outer formwork. The formwork and the installation of the steel bars 18 should be coordinated with each other. If the formwork interferes with the tying of the steel bars 18, the formwork should be erected after the steel bars 18 are installed.

[0062] Before the steel bars 18 are put in place, the steel bar model, size, shape and quantity must be checked again. If there are any errors or omissions, they should be corrected or supplemented to ensure that the binding position and spacing of the steel bars 18 are accurate.

[0063] Before construction, you should first be familiar with the drawings and carefully review the positional relationship between the steel bars 18 and the embedded parts, reserved holes, and formwork. You should also clarify whether the construction of the steel bars 18 intersects with the formwork and the construction of the direct-buried bolts, and the order of their intersection.

[0064] The binding of steel bars 18 should ensure the verticality of the main bars, the cross-sectional dimensions and the protective layer dimensions, the spacing and position dimensions of steel bars 18, and the opening positions should be constructed according to the design requirements.

[0065] The reinforcement 18 is tied up once as per the design, and cement mortar pads are used to ensure the protective layer of the concrete according to the specifications and design. The pads are tied tightly with pre-buried iron wire and reinforcement 18 and are staggered in arrangement.

[0066] When using a double-layer steel mesh, steel support legs and X-shaped supporting steel bars are set under the upper steel mesh.

[0067] For on-site connections of large-diameter rebar (18mm) with a diameter ≥ 25mm, straight thread connections should be used. For thinner rebar, lap welding or binding may be used. Joints should be located where internal forces are minimal and staggered. The number of lap joints for rebar (18mm) in the same section should not exceed 50% of the total number.

[0068] When rebar 18 encounters a hole, it should be routed around it as much as possible and should not be cut. If cut is necessary, it should be reinforced with ring reinforcement welded to the hole. During the tying process, the rebar workers should coordinate with the carpenters to ensure that the rebar is firmly fixed to avoid uneven spacing of the rebar after the concrete is poured due to loosening.

[0069] After binding and welding are completed and passed inspection, the formwork can be sealed. Protective measures should be taken for inserted rebar and embedded parts to prevent mortar contamination during concrete pouring. Pipe fittings and construction bolts penetrating reinforced concrete walls should be equipped with waterstop rings. Tool-type bolts can be used for tension bolts securing the formwork. A square waterstop must be welded to the center of the bolts. The waterstop should be fully welded to the bolts. After removing the formwork, the bolts should be cut off and the component surface should be sealed with polymer cement slurry.

[0070] When installing the formwork: the surface of the formwork should be coated with an isolation agent, and the isolation agent selected should not affect the aesthetics of the exposed surface of the structure. The surface of the formwork must be flat and clean, the geometric dimensions must be accurate, the joints must be tight, and no leakage of slurry is allowed. Sponge strips are pasted on all joints to ensure that the joints are tight and prevent leakage of slurry. The installed formwork must have sufficient strength, rigidity and stability to ensure the accuracy specified by the structural dimensions and the accuracy of the spatial position of the structure. The embedded parts and reserved holes fixed to the formwork must not be omitted. The position, surface flatness and elevation of the embedded parts must comply with the requirements of the design and specifications, and meet the requirements of straightness, flatness, regularity and first-class visual quality.

[0071] Step 3: Assemble the welding-free connection structure. Connect the upper left connector 2-1, the lower left connector 2-2, the upper right connector 3-1 and the lower right connector 3-2 through mortise and tenon joints to form the left connector 2 and the right connector 3. Insert the waterstop steel plate 1 into the slot formed by the bent flanges of the left connector 2 and the right connector 3. Then pass the rotating shaft 4 through the circular holes of the left connector 2 and the right connector 3. Fix the rotating shaft 4, the left connector 2 and the right connector 3 into a whole through the cap nut 7 and the nut 8 to achieve the connection of the two waterstop steel plates 1. When the connected waterstop steel plates are at a corner, the left connector 2 and the right connector 3 rotate around the rotating shaft 4 to a specific angle, connect the spring 5 to the hanging rings 9 of the left connector 2 and the right connector, and insert the two ends of the steel rod 6 into the holes 10 of the left connector 2 and the right connector 3 to achieve angle fixation.

[0072] A fixing device is installed in the middle section of the waterstop steel plate 1. The upper connector 11 and the lower connector 12 are connected by mortise and tenon joints to form a whole and connect the waterstop steel plate 1. The position adjustment bolt 13 on the back of the upper connector 11 is inserted into the horizontal position adjustment hole 15 of the connector 14. The position adjustment bolt 13 on the top of the connector 14 is inserted into the vertical position adjustment hole 17 of the steel bar clamp 16. The steel bar clamp 16 clamps the vertical steel bar 18 through the connecting steel bar connection hole 19, hinge 20 and closure 21, and the lower end is placed on the horizontal steel bar 18 to fix the waterstop steel plate 1. The height and position of the waterstop steel plate 1 are adjusted by the position adjustment bolt 13 so that the lower end of the waterstop steel plate 1 extends into the casting range of the lower section in the adjacent caisson section.

[0073] Step 4: Cast the lower segment of the adjacent caisson segment. When the old concrete reaches 70% of the design strength, pull out the closure 21, take out the steel clamp 16, and remove the connector 14 and the upper connector 11. Unscrew the nut 6 at the corner, pull out the rotating shaft 4, remove the upper connector 2-1 and the upper connector 3-1, and fill the circular holes of the lower connector 2-2 and the lower connector 3-2 with waterproof material. Waterproof material is used to fill the original position of the rotating shaft 4 to make up for the gap between the water-stop steel plates 1 after the rotating shaft 4 is pulled out, which has good sealing and water-stopping effect. The closure 21, steel clamp 16, connector 14, upper connector 11, nut 8, rotating shaft 4, upper left connector 2-1 and upper right connector 3-1 can all be recycled.

[0074] After the first section of the caisson structure is produced, the control points of the structure center and axis are led to the well wall of the structure. At the same time, settlement observation points are arranged at the four corners of the structure. The control points of the well body can be used to measure the plane dimensions of the structure and control the verticality of the well body during the production of the caisson upper structure.

[0075] After pouring the caisson segments, generally 48 hours after the concrete pouring is completed, the tension bolts of the caisson wall can be loosened and the formwork and fastener-type steel pipes can be removed. The caisson straight wall formwork should not be removed until the concrete reaches more than 25% of the design strength. The operation sequence is to remove the formwork and fastener-type steel pipes from top to bottom and from the inside to the outside. After the lower section is made, the formwork cannot be completely removed. More than 1m must be left to support the upper section formwork. After the formwork is removed, a 5cm diameter and 2cm deep pit should be chiseled in the concrete surface at the root of the tension screw. Then, the tension bolts should be cut off, the pit should be filled with waterproof mortar for a second time, and waterproof material should be applied twice. For the suspended part of the larger hole, the concrete bottom formwork should be removed as required when the concrete strength reaches 80% of the design strength. After the formwork is removed, the measurement level marks should be sprayed at the four corners of the well, and the measurement caisson displacement mark should be sprayed at the top of the well.

[0076] After the side formwork of the well wall is removed, straw bags should be hung in time and water should be sprinkled for maintenance to keep the concrete surface moist, and the maintenance time should not be less than 7 days.

[0077] The time for removing the formwork should be determined based on the concrete grade, pouring sequence and stress conditions. The concrete strength when the formwork and support are removed should meet the design requirements. When there are no specific requirements in the design, it should comply with the provisions of the specifications, that is: non-load-bearing side formwork should not be removed until the concrete strength can ensure that its surface and edges are not damaged by removing the formwork; the load-bearing formwork of reinforced concrete structures can not be removed until the concrete strength reaches more than 75% of the design strength; the demolding time of concrete components cast on-site underwater and in water level fluctuation areas should be appropriately extended.

[0078] The removal of the formwork in the reserved holes should ensure that the concrete surface does not collapse or crack, and vibration and damage to the hole wall should be avoided during removal of the formwork.

[0079] After dismantling, the formwork and its accessories should be cleaned of any mortar and dirt that adheres to it. Deformed and damaged formwork should be reshaped and repaired, and maintained. They should be stored in a classified manner and carefully cared for to prevent deformation and cracking, so as to increase the number of times the formwork can be used. It is prohibited to continue using the formwork without cleaning, repairing and maintaining it.

[0080] Example 4

[0081] As another embodiment, this fourth embodiment, based on the third embodiment, proposes a more specific method for constructing a caisson with a waterproof structure of a weld-free water-stop steel plate.

[0082] Step 5 is also included after step 4. Specifically, step 5 is to continue to simultaneously install the water-stop steel plate 1 and cast and sink the caisson in sections, cast the upper end of the water-stop steel plate 1 exposed after the last casting in the caisson section, and cast the lower end of the new water-stop steel plate 1 at the top of the caisson stage; repeat steps 2 to 5 until all sections of the caisson are cast.

[0083] During concrete construction, the caisson will be divided into several sections and poured symmetrically and evenly in layers, with each layer 30 cm thick, to avoid uneven sinking or tilting of the foundation; concrete pouring is carried out using a layered method, and the thickness of each layer is strictly prohibited to be greater than 50 cm. The upper and lower layers of concrete must be stepped, and the time interval between the pouring of the upper and lower layers of concrete must not be greater than the initial setting time of the concrete.

[0084] During pouring, place vibrators at each pouring point, ensuring the vibrator rod length matches the pouring height. When vibrating concrete, pay attention to the insertion time and spacing of the vibrator rods, inserting them quickly and withdrawing them slowly, ensuring even placement. When vibrating the upper layer of concrete, insert the rod approximately 10 cm into the lower layer to eliminate any gaps between the two layers.

[0085] When pouring structural concrete, settlement observation points should be arranged on the well wall. Observations should be carried out during the pouring process and the curing period to keep track of the amount of sinking and tilting of the caisson in a timely manner, providing a basis for the production of the next section.

[0086] Concrete should be poured in a single, continuous pour. The second section can only be poured after the first section reaches 70% of its design strength. A 0.5-1.0m height should be reserved for the next section of concrete pouring during the caisson sinking process. Natural curing is permitted for the concrete. To expedite formwork removal and sinking, an antifreeze and early strength-accelerating agent can be added to the concrete in winter. During concrete construction, ensure that the required secondary reinforcement is not omitted.

[0087] After dismantling the components, roughen and flush the joints before pouring the next section. Before pouring, pour a layer of half-gravel concrete. The compressive strength of the poured concrete must be no less than 1.2 MPa. The hardened concrete surface should be cleaned of any cement film and loose gravel, thoroughly moistened, and flushed to prevent any accumulation of water. Before pouring, apply a 10-15 mm thick layer of cement slurry with the same composition as the concrete. All secondary concrete surfaces must be roughened, and the relative temperature difference during secondary concrete pouring must be controlled below 7-8°C.

[0088] When the caisson sinks, the concrete strength of the first section should reach the design strength, and the remaining sections should reach 70% of the design strength.

[0089] Example 5

[0090] As another embodiment, this fifth embodiment proposes a more specific construction method of a caisson with a welding-free water-stop steel plate waterproof structure, which also includes a specific construction method of the caisson and the bottom waterproof structure.

[0091] Before sinking, all reserved holes in the caisson wall are sealed with C35 plain concrete to enhance the integrity and meet the requirements of resisting soil pressure and water pressure during sinking, while also considering ease of dismantling.

[0092] Laying out the lines for positioning. Before the caisson is lowered, four vertical lines are drawn symmetrically on the inner and outer walls to measure the caisson's inclination as it sinks. A plumb bob is hung at the top of each of the four vertical lines inside the caisson, and a scale plate is placed at the blade foot 23. During the caisson sinking operation, the caisson's inclination is monitored at all times for timely correction. A horizontal measuring scale is drawn along the four vertical lines on the outer wall of the caisson to measure the caisson's sinking amount and sinking deviation, while also controlling the water level in the pit.

[0093] Before removing the concrete cushion layer, all concrete cushion layers should be grouped and numbered symmetrically at intervals. When removing the concrete, work should be carried out in groups, symmetrically and synchronously. Only after the concrete cushion layer with the same number has been removed and backfilled can the next group of numbered concrete cushion layers be removed. After a group of concrete cushion layers is removed, it must be backfilled in time, and the backfill material should be medium-coarse sand.

[0094] The caisson sinks without drainage, using mechanical excavation and sinking techniques. When the sinking coefficient is large, the center is excavated first, retaining the soil around the blade foot 23 and allowing it to sink. When the sinking coefficient is small, the surrounding area is excavated first, followed by the center, forming the pot bottom. Generally, when the pot bottom is 1 to 1.5 meters lower than the blade foot 23, the caisson sinks under its own weight, pushing the soil below the blade foot 23 toward the central pot bottom. Further soil is then grabbed from within the caisson, allowing it to continue sinking. Grabbing soil should be done symmetrically to ensure even sinking, and the height difference of the soil surface within the caisson should not be too large.

[0095] During the sinking process, frequently observe the inclination of the caisson and the elevation of the blade foot 23. When the burial depth of the blade foot 23 is less than 1 / 3 of the caisson height, focus on observing the inclination of the caisson shaft. When the elevation of the tread of the blade foot 23 sinks to approximately 2m from the design elevation, strengthen observations of the tread elevation and the amount of sinking.

[0096] Caisson verticality control: Mark the vertical axis in eight equal sections within the shaft. Align each plumb bob with the marking plate below for control. Regularly observe vertical deviations using two theodolites. While excavating, observe verticality at all times. If the plumb bob deviates from the ink line by 50mm or if the surrounding elevations are inconsistent, correct the problem immediately.

[0097] Caisson sinking control: Use a level to observe settlement by marking horizontal lines around the caisson wall. Observation: During the caisson sinking process, the position, verticality, and settlement values ​​should be carefully monitored. Measurements should be taken twice: during sinking and after each sinking. When approaching the design elevation, observations should be made every two hours to prevent oversinking. A dedicated person should be responsible for this and maintain records. Any tilt, displacement, or torsion should be corrected promptly.

[0098] After the caisson sinks to the designed elevation, a fixed guardrail is set up 1m outside the caisson, and a green net and safety warning sign are hung as safety protection during the subsequent construction process.

[0099] The bottom seal concrete should be commercial concrete with a slump of 18-22 cm and a spread of 170-200 cm. It should maintain a thickness of at least 19 cm for 1 hour and at least 15 cm for 6 hours. The initial setting time of the concrete mixture should be greater than 10 hours, and the final setting time should be greater than 15 hours. It should be workable, non-bleeding, pumpable, and highly fluid and diffusible.

[0100] This project arranges one conduit, and the bottom of the conduit is 30cm away from the mud surface. During the first pouring, the site needs to meet the requirements of 2 trucks of concrete of not less than 24m 3 , the pump truck pumps concrete into the hopper to ensure continuous supply for the first time.

[0101] The concrete hopper is lifted by a crane, and the bottom is poured into the mud by lifting the conduit through the lower hopper. The conduit is opened by using a bladder, which is pre-stuck at the bottom of the concrete hopper. When the concrete is poured, it is pressed out from the bottom of the conduit and floats on the mud surface.

[0102] Throughout the pouring process, the concrete conduit should be buried 2 to 4 meters deep, with a minimum depth of no less than 1.5 meters. This will draw the slurry near the rising surface into the concrete. It should also not be buried deeper than 6 meters, as this will affect the flow of concrete. The conduit should be raised as the pour progresses to avoid concrete voids caused by raising it too quickly or the inability to remove the buried conduit due to over-extension. During pouring, the pressure differential between the continuous pouring and the concrete at the conduit outlet is used to continuously squeeze concrete out of the conduit, causing the concrete surface to gradually rise.

[0103] Concrete pouring should be done in one go without interruption. To ensure the uniformity of the concrete, the interval time should generally be controlled within 15 minutes and should not exceed 30 minutes. When pouring, it is necessary to ensure that the concrete surface in the trough rises evenly and the rising speed of the concrete surface is not more than 2m / h. The pouring speed is generally 30-35m 3 / h. The conduit cannot move laterally, otherwise the mud will mix into the concrete. During the concrete pouring process, the actual height of the concrete surface should be measured at least three times with a hammer and the average value should be taken.

[0104] After the bottom seal is completed, the diver checks whether the bottom seal concrete is full, especially the notch. If an incomplete part is found, the conduit will be moved to the weak point while ensuring the buried depth of the conduit.

[0105] The bottom plate construction can be carried out only after the caisson bottom concrete construction is completed and the concrete strength reaches 100%.

[0106] A groove is formed on the inner sidewall of the upper portion of the blade foot 23 at the bottom of the caisson. The groove walls are evenly distributed with trapezoidal annular grooves 24 from top to bottom. The lower surface of each annular groove is paved with a closed annular waterstop 25. The sidewalls of the bottom plate 26 are formed into a convex structure that complements the waterstop groove. The convex block is embedded in the trapezoidal annular groove 24, and the lower surface of the convex block fits in with the annular waterstop 25. The concave-convex connection structure interrupts the leakage and seepage channel of the original linear construction joint, increases the effective contact area length of the construction joint, and has a significant water-stopping effect. Furthermore, the trapezoidal groove avoids the problem of secondary pouring being difficult to compact.

[0107] A card groove is provided on the inner wall of the caisson body above the bottom seal. Specifically, at the bottom of the groove, the edge of the waterproof membrane 27 is located in the card groove and fixed with a clamping ring 28, thereby further improving the waterproof effect of the bottom of the caisson.

[0108] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A caisson with a waterproof structure of a non-welding water-stop steel plate, characterized by: Water-stop steel plates (1) are provided at the construction joints of upper and lower adjacent caisson segments through a fixing device, and two adjacent water-stop steel plates (1) at a corner are connected to each other through a welding-free connection structure; a bottom plate (26) is embedded above the blade foot (23) of the caisson through a groove; The welding-free connection structure comprises a left connection piece (2) and a right connection piece (3), each of which comprises an upper and a lower part connected by a mortise and tenon joint. The left connection piece (2) and the right connection piece (3) are connected by a rotating shaft (4), and the ends of two water-stop steel plates (1) at the corners are respectively inserted into the left connection piece (2) and the right connection piece (3). A spring (5) and a steel rod (6) are provided on the back of the welding-free connection structure for fixing the expansion angle of the left connection piece (2) and the right connection piece (3); The fixing device comprises an upper connecting member (11), a lower connecting member (12) and a steel bar clamp (16); the upper connecting member (11) is rotatably connected to a position adjusting bolt (13) on its back side; the position adjusting bolt (13) is threadedly connected to a connecting member (14); the upper side of the connecting member (14) is also rotatably connected to a position adjusting bolt (13); the steel bar clamp (16) is threadedly connected to the position adjusting bolt (13) above the connecting member (14); and the steel bar clamp (16) is clamped on a steel bar (18) of an upper section in an adjacent caisson section; The flanges of the upper and lower parts of the left connecting member (2) and the right connecting member (3) are both provided with slots corresponding to the upper and lower ends of the water-stop steel plate (1); the sides where the left connecting member (2) and the right connecting member (3) are connected to each other are alternately provided with shaft cylinders; when the left connecting member (2) and the right connecting member (3) are connected, the rotating shaft (4) is inserted into the shaft cylinders that are connected in sequence; the upper and lower ends of the rotating shaft (4) are respectively connected to the outside of the shaft cylinder by a nut (8) and a cap nut (7) through a thread; The left connecting member (2) includes an upper left connecting member (2-1) and a lower left connecting member (2-2); the right connecting member (3) includes an upper right connecting member (3-1) and a lower right connecting member (3-2); shaft cylinders are staggeredly provided at the connection between the upper left connecting member (2-1) and the upper right connecting member (3-1); and the length of the shaft cylinders after being connected is equal to the height of the upper left connecting member (2-1) and the upper right connecting member (3-1); shaft cylinders are also staggeredly provided at the connection between the lower left connecting member (2-2) and the lower right connecting member (3-2); and the length of the shaft cylinders after being connected is equal to the height of the lower left connecting member (2-2) and the lower right connecting member (3-2); The backs of the upper left connecting piece (2-1) and the upper right connecting piece (3-1) are both provided with a lifting ring (9) and a steel rod hole (10); the two ends of the spring (5) are respectively connected to the lifting rings (9) of the upper left connecting piece (2-1) and the upper right connecting piece (3-1); and the two ends of the steel rod (6) are respectively inserted into the steel rod holes (10) of the upper left connecting piece (2-1) and the upper right connecting piece (3-1).

2. The caisson with a waterproof structure of a non-welding water-stopping steel plate according to claim 1 is characterized in that: An adjusting bolt connection hole (22) is provided on the back of the upper connecting member (11), and a horizontal position adjusting hole (15) is provided on the connecting member (14). One end of the position adjusting bolt (13) is rotatably arranged in the adjusting bolt connection hole (22), and the other end is threadedly penetrated into the horizontal position adjusting hole (15); an adjusting bolt connection hole (22) is also provided on the top of the connecting member (14), and a position adjusting bolt (13) is rotatably connected to the adjusting bolt connection hole (22). The steel bar clamp (16) is connected to the position adjusting bolt (13) through the vertical position adjusting hole (17).

3. The caisson with a waterproof structure of a non-welding water-stopping steel plate according to claim 1 is characterized in that: The steel bar clamp (16) includes a symmetrical two-flap opening and closing structure, which is connected by a hinge (20) and a closure (21). The opening and closing surface is parallel to the horizontal steel bars (18) in the caisson segment. The two-flap opening and closing structure is provided with semicircular grooves on the opening and closing surface. When the steel bar clamp (16) is closed, the two semicircular grooves form a vertical steel bar connection hole (19) and are sleeved on the vertical steel bars (18) of the upper segment in the adjacent caisson segment. The bottom of the steel bar clamp (16) is supported on the horizontal steel bars (18) of the upper segment in the adjacent caisson segment through a semicircular groove.

4. The caisson with a waterproof structure of a non-welding water-stopping steel plate according to claim 1 is characterized in that: A groove is provided on the inner wall of the caisson above the blade foot (23), and several layers of trapezoidal annular grooves (24) are distributed on the groove wall of the groove. The bottom of each layer of the trapezoidal annular groove (24) is provided with an annular water stop (25). The edge of the bottom plate (26) is provided with several layers of protrusion structures matching the trapezoidal annular grooves (24). The protrusions are embedded in the trapezoidal annular grooves (24), and the lower surfaces of the protrusions are in contact with the annular water stop (25). A waterproof roll (27) is provided between the bottom plate (26) and the bottom seal of the caisson, and the edge of the waterproof roll (27) is fixed to the bottom of the groove by a clamping ring (28).

5. The construction method of a caisson with a waterproof structure of a non-welding water-stop steel plate according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: excavate the foundation pit, lay a sand cushion layer, and cast the blade foot (23) on the sand cushion layer; Step 2: tying steel bars (18) and erecting formwork for the caisson in the foundation pit; Step 3: Assemble the welding-free connection structure. The ends of the two water-stop steel plates (1) are respectively inserted into the left connection piece (2) and the right connection piece (3). After the welding-free connection structure is unfolded around the rotation axis (4) to match the rotation angle, the angle is fixed by the spring (5) and the steel rod (6); A fixing device is installed in the middle section of the water-stop steel plate (1), and a steel bar clamp (16) is clamped on the steel bar (18) of the upper middle section of the adjacent caisson segment. The height and position of the water-stop steel plate (1) are adjusted by the position adjustment bolt (13) so that the lower end of the water-stop steel plate (1) extends into the casting range of the lower middle section of the adjacent caisson segment; Step 4: Cast the lower segment of the adjacent caisson segments. When the concrete reaches a certain strength, remove the steel clamp (16) and the upper connector (11) in the fixing device, pull out the rotating shaft (4), remove the upper half of the left connector (2) and the right connector (3) in the welding-free connection structure, and fill with waterproof material.

6. The construction method of a caisson with a waterproof structure of a non-welding water-stop steel plate according to claim 5, characterized in that: Step 5 is also included after step 4. Step 5 specifically includes continuing to simultaneously install the water-stop steel plate (1) and cast and sink the caisson in sections, casting the upper end of the water-stop steel plate (1) exposed after the last casting into the caisson section, and casting the lower end of the new water-stop steel plate (1) at the top of the caisson stage; repeating steps 2 to 5 until all sections of the caisson are cast.

7. The construction method of a caisson with a waterproof structure of a non-welding water-stop steel plate according to claim 6 is characterized in that: After the caisson concrete is poured in sections, the bottom is sealed, and then a waterproof roll (27) is fixed to the bottom of the groove above the blade foot (23) through a clamping ring (28), and several layers of annular water stop strips (25) are set in the groove above the waterproof roll (27) and embedded in the bottom plate (26).

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