Connecting structure and assembling method of fabricated underground continuous wall

Abstract

The application discloses a connecting structure and a splicing method of an assembled underground continuous wall, and the connecting structure comprises a steel lattice connecting piece, a positioning angle steel, a fastener and a UHPC plate, the steel lattice connecting piece is arranged in a groove at the bottom of an upper segment underground continuous wall; a plurality of stiffening rib plates are arranged in cavities between upper end plates and lower end plates of the steel lattice connecting piece; an L-shaped groove is formed on each side of the top of a lower segment underground continuous wall; the positioning angle steel is prefabricated with the lower segment underground continuous wall, the positioning angle steel covers the top surface edge of the lower segment underground continuous wall and the vertical wall surface of the L-shaped groove; the positioning angle steel and the steel lattice connecting piece are connected through high-strength bolts; the UHPC plate is clamped and covers the L-shaped groove and the steel lattice connecting piece on the upper segment underground continuous wall and the lower segment underground continuous wall, and grouting sealing materials are poured into cavities of the steel lattice connecting piece. The structure is convenient to install, has a tolerance capacity, a bearing capacity and a strong shearing force.

Description

Technical Field

[0001] This invention belongs to the field of underground structure engineering technology, specifically relating to a connection structure and assembly method for prefabricated underground continuous walls. Background Technology

[0002] Underground engineering structures mainly include shield tunnels, immersed tunnels, integrated utility tunnels, subway stations, and diaphragm wall structures. Many cities in my country have successively carried out research and application of prefabricated underground station structures and diaphragm wall structures. Due to limitations in the fabrication, transportation, and installation of prefabricated components, their size and weight cannot be too large. Therefore, prefabricated structures have a large number of joints and seams. Joint connection technology is one of the core technologies of prefabricated underground structures, determining the overall structural load-bearing performance, waterproofing performance, construction speed, and project cost.

[0003] In underground station structures, prefabricated diaphragm walls typically range from 15 to 35 meters in depth, presenting challenges in transportation and hoisting. Therefore, segmented prefabrication and assembly are necessary. Lateral joints in prefabricated diaphragm walls generally utilize steel profiles or steel bar / pipe anchoring connections. Steel profile connections involve complex procedures, require a large amount of steel, and necessitate numerous bolts for on-site tightening, impacting construction efficiency and project cost. Steel bar / pipe anchoring connections use less steel, but the epoxy resin cannot immediately provide load-bearing capacity, necessitating the use of additional high-strength bolts to ensure structural safety during construction. Summary of the Invention

[0004] To address the problems existing in the prior art, one objective of this invention is to provide a connection structure for prefabricated underground continuous walls.

[0005] Another objective of this invention is to provide a method for assembling prefabricated underground continuous walls using the above-mentioned connection structure.

[0006] Therefore, the present invention adopts the following technical solution:

[0007] A connection structure for a prefabricated diaphragm wall includes steel lattice connectors, positioning angle steel, fasteners, and UHPC plates. The structure comprises: a groove formed on each side of the bottom of an upper segment of the diaphragm wall, extending along the length of the upper segment; the steel lattice connectors are disposed within the grooves and prefabricated together with the upper segment of the diaphragm wall; each steel lattice connector is formed by connecting a vertically arranged back plate to parallel upper and lower end plates on the same side, resulting in a U-shaped vertical cross-section opening to one side; multiple stiffening ribs are spaced apart in the cavity between the upper and lower end plates, dividing the cavity into multiple independent chambers; a bolt hole is formed on each of the upper and lower end plates at a position corresponding to each chamber; the upper end plate is fastened by a first high-strength bolt and nut pre-embedded in the upper segment of the diaphragm wall and extending from the bolt hole in the lower end plate; the lower segment of the diaphragm wall... The top two sides of the diaphragm wall are recessed inward to form an L-shaped groove, which extends along the length of the upper diaphragm wall segment. The positioning angle steel is prefabricated together with the lower diaphragm wall segment, and the two sides of the positioning angle steel cover the top edge of the lower diaphragm wall segment and the vertical wall of the L-shaped groove. The positioning angle steel located on the top surface of the lower diaphragm wall segment has bolt holes corresponding to the position and number of bolt holes on the lower end plate. Multiple second high-strength bolts pre-embedded in the top of the lower diaphragm wall segment pass through the bolt holes on the positioning angle steel and the lower end plate, respectively, and are locked with nuts. L-shaped grooves are also formed at the positions corresponding to the L-shaped grooves of the upper and lower diaphragm wall segments. A UHPC board is snapped onto and covers the L-shaped grooves on the upper and lower diaphragm wall segments and the steel lattice connector. Grouting sealing material is injected into the cavity of the steel lattice connector.

[0008] Preferably, the steel lattice connectors on both sides of the bottom of the upper stage diaphragm wall are connected together by tie bars.

[0009] In one embodiment of the present invention, a positioning pin is provided at the top of the lower segment of the diaphragm wall, and a positioning pin hole is provided at the corresponding position at the bottom of the upper segment of the diaphragm wall.

[0010] In another embodiment of the present invention, a positioning pin is provided at the bottom of the upper segment of the diaphragm wall, and a positioning pin hole is provided at the corresponding position at the top of the lower segment of the diaphragm wall.

[0011] Preferably, the bottom surface of the lower end plate is flush with the bottom of the upper diaphragm wall segment; the top surface of the positioning angle steel is higher than the top surface of the lower diaphragm wall segment; and epoxy resin is used to fill the gap between the upper and lower diaphragm wall segments. Preferably, vertical joint caulking material is used to fill the gap between two adjacent diaphragm walls; and the vertical wall surface of the positioning angle steel extends into the wall body of the lower diaphragm wall segment.

[0012] Preferably, epoxy resin is applied to the outer side of the steel lattice connector and the inner side of the UHPC plate, and grouting holes and venting holes are pre-drilled on the UHPC plate. The spacing between the stiffening ribs is consistent with the spacing between the first high-strength bolts (second high-strength bolts); connecting holes are provided on the stiffening ribs to facilitate the rapid filling of the entire cavity of the steel lattice connector with grouting sealing material;

[0013] A method for assembling prefabricated diaphragm walls using an upper connection structure includes the following steps:

[0014] Precast the upper and lower segments of the underground diaphragm wall, and then transport them to the construction site;

[0015] Construction of diaphragm walls: First, hoist the lower segment of the diaphragm wall into the excavated trench wall. Use steel beams to fix the lower segment of the diaphragm wall above the guide wall. Hoist the upper segment of the diaphragm wall above the lower segment, align it, and slowly lower it. Use positioning pins for positioning assistance. Insert the second high-strength bolt, which is pre-embedded in the top of the lower segment of the diaphragm wall, into the bolt holes of the lower end plate of the steel lattice connector located at the bottom of the upper segment of the diaphragm wall. Tighten the connection with nuts and washers. Leave a 2-3mm gap between the upper and lower segments of the diaphragm wall and fill it with epoxy resin.

[0016] After the joint is assembled, epoxy resin is applied to the outside of the steel lattice connector and the side of the UHPC plate. The UHPC protective plate is then installed on the outside of the steel lattice connector, and grout is injected into the steel lattice connector through the grouting holes reserved on the UHPC plate.

[0017] The connection structure for prefabricated diaphragm walls of this invention can be used for connecting upper and lower segments of diaphragm walls, and can also be applied to connecting main structural components of underground stations, showing great promise for application in prefabricated underground structures. Compared with the prior art, this invention has the following advantages:

[0018] 1. In this invention, the steel lattice connector and the upper segment of the diaphragm wall are prefabricated together, and the steel lattice connectors on the inner and outer sides of the wall are connected into a whole by tie bars; the first high-strength bolts pre-embedded in the wall pass through the bolt holes of the upper end plate and are fastened with nuts. On the construction site, only the second high-strength bolts pre-embedded in the lower segment of the diaphragm wall need to be fastened, and the assembly speed is fast.

[0019] 2. In this invention, the pre-embedded second high-strength bolt is positioned with the aid of positioning angle steel and steel lattice connector, and has a horizontal accuracy of ±1mm; the hole in the lower end plate of the steel structure connector is larger than the bolt diameter, with a tolerance of ±5mm, ensuring smooth assembly on site.

[0020] 3. Stiffening ribs are welded between the upper and lower end plates of the steel lattice connector to form an independent cavity structure, which effectively improves the stiffness of the connector and reduces its deformation. The spacing of the stiffening ribs is consistent with that of the connecting high-strength bolts. After the steel lattice connector is assembled, a prefabricated UHPC panel is installed on the outside for protection. The steel clips in the UHPC panel are used for quick installation. Epoxy resin is applied to the sides of the UHPC panel to ensure connection quality and prevent grout leakage. Grouting is performed inside the connector through the grouting holes in the UHPC panel to solve the corrosion problem. The stiffening ribs are provided with connecting holes to ensure that the grout fills the entire connector.

[0021] 4. In this invention, a 2-3mm gap is reserved at the splicing interface of the upper and lower segments of the diaphragm wall, which is filled with epoxy resin to improve the waterproof and load-bearing capacity of the joint; steel positioning pins are set at the splicing interface of the upper and lower segments of the diaphragm wall to assist in positioning and improve the shear bearing capacity of the joint. Attached Figure Description

[0022] Figures 1-3 These are all schematic diagrams of the connection structure of the prefabricated underground continuous wall in the embodiments of the present invention, wherein... Figure 1 This is a side view. Figure 2 This is a front view. Figure 3 This is a top view;

[0023] Figure 4 and Figure 5 This is a schematic diagram of the installation process of the sliding UHPC protective plate in an embodiment of the present invention;

[0024] Figure 6 and Figure 7 This is a schematic diagram of the installation process of the push-type UHPC protective plate in an embodiment of the present invention.

[0025] in:

[0026] 1a. First high-strength bolt; 1b. Second high-strength bolt; 2. Nut; 3. Upper end plate; 4. Back plate; 5. Lower end plate;

[0027] 6. Positioning angle steel; 7. Grouting and sealing material; 8. UHPC board; 9. Steel positioning pins; 10. Epoxy resin;

[0028] 11. Stiffening ribs; 13. Vertical joint caulking material; 14. End plate bolt holes; 15. Grouting holes; 16. C-shaped channel steel;

[0029] 17. Connecting hole; 18. Spring pin; 19. First recess; 20. Second recess. Detailed Implementation

[0030] The connection structure of the prefabricated underground continuous wall of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0031] Figures 1 to 3 The diagram shows a prefabricated diaphragm wall connection structure according to an embodiment of the present invention. As shown, in the diaphragm wall, the upper and lower diaphragm wall segments (referred to as diaphragm walls in the diagram) are assembled using a connection structure. The connection structure includes steel lattice connectors, positioning angle steel 6, fasteners, and UHPC (Ultra-High Performance Concrete) panels 8, wherein:

[0032] A groove is formed on each side of the bottom of the upper segment of the diaphragm wall, extending along the length of the upper segment. The steel lattice connector is installed within the groove and prefabricated with the upper segment of the diaphragm wall. The steel lattice connector is formed by connecting a vertically arranged back plate 4 to two parallel upper end plates 3 and lower end plates 5 on the same side, resulting in a U-shaped vertical cross-section that opens to one side. Multiple stiffening ribs 11 are spaced apart in the cavity between the upper end plate 3 and the lower end plate 5, dividing the cavity into multiple independent chambers, effectively improving the stiffness of the connector and reducing its deformation. A bolt hole is formed at each position on the upper end plate 3 and the lower end plate 5 corresponding to each chamber. The upper end plate 3 is secured by a first high-strength bolt and nut pre-embedded in the upper segment of the diaphragm wall and extending from the bolt hole on the lower end plate. The welding strength between the components of the steel lattice connector should not be lower than the strength of the base material. The material of each component of the steel lattice connector can be Q235 or Q355.

[0033] An L-shaped groove is formed by indenting on both sides of the top of the lower segment of the diaphragm wall, and the L-shaped groove extends along the length of the upper segment of the diaphragm wall; the positioning angle steel 6 is prefabricated together with the lower segment of the diaphragm wall, and the two sides of the positioning angle steel 6 cover the top edge of the lower segment of the diaphragm wall and the vertical wall of the L-shaped groove; the positioning angle steel located on the top surface of the lower segment of the diaphragm wall is provided with bolt holes corresponding to the position and number of bolt holes on the lower end plate; multiple second high-strength bolts pre-embedded in the top of the lower segment of the diaphragm wall pass through the bolt holes of the positioning angle steel and the lower end plate respectively, and are locked by nuts;

[0034] An L-shaped groove is also formed at the position corresponding to the L-shaped groove of the upper segment diaphragm wall and the lower segment diaphragm wall. A UHPC plate 8 is snapped onto and covers the L-shaped groove on the upper segment diaphragm wall and the lower segment diaphragm wall, as well as the steel lattice connector. Grouting sealing material 7 is injected into the cavity of the steel lattice connector.

[0035] Specifically, at the bottom of the front and back sides of the upper segment of the diaphragm wall, two steps are formed by inward indentation; at the top of the front and back sides of the lower segment of the diaphragm wall, one step is formed by inward indentation. This results in two recessed portions at the connection between the bottom of the upper segment and the top of the lower segment, namely, the first recessed portion 19 and the second recessed portion 20. These two recessed portions extend along the length of the diaphragm wall (see...). Figure 2 The steel lattice connector is disposed within the second recess 20, and the length of the steel lattice connector is the same as the length of the second recess 20. The steel lattice connector is prefabricated together with the diaphragm wall.

[0036] See Figure 2 The first and second high-strength bolts 1a and 1b are pre-embedded at the bottom of the upper segment of the diaphragm wall and the top of the lower segment of the diaphragm wall, respectively. They can be welded to the main reinforcing bars of the diaphragm wall. One high-strength bolt can be welded to one or two reinforcing bars, and the diameter and spacing of the reinforcing bars can be flexibly arranged. The spacing of the stiffening ribs 11 is consistent with the spacing between the first high-strength bolts (or the second high-strength bolts).

[0037] The pre-embedded second high-strength bolt is positioned using positioning angle steel 6 and steel lattice connectors, with a horizontal accuracy of ±1mm. The bolt hole diameter on the lower end plate of the steel lattice connector is larger than the diameter of the second high-strength bolt, with a tolerance of ±5mm, ensuring smooth assembly on site.

[0038] The top two sides of the lower segment of the diaphragm wall are recessed inward to form an L-shaped groove extending along its length. An L-shaped positioning angle steel, enclosing the right angle of the top of the diaphragm wall, is pre-embedded on each side of the top of the lower segment of the diaphragm wall along its length. Multiple high-strength bolts, pre-embedded at intervals in the top of the lower segment of the diaphragm wall, extend outward through through holes in the L-shaped positioning angle steel. The position and number of through holes in the L-shaped positioning angle steel correspond to the position and number of through holes on the lower end plate 5 of the connector.

[0039] Pre-embedded high-strength bolts are inserted into the bolt holes of the lower end plate 5 using L-shaped positioning angle steel, and then tightened using nuts and washers. Steel positioning pins and epoxy resin filling are used between the upper and lower segments of the diaphragm wall to improve the positioning, waterproofing, and load-bearing performance of the joint. (Refer to...) Figure 2 and Figure 3In the vertical direction of the two sets of diaphragm wall assembly, the vertical joint caulking material 13 of the diaphragm wall is used for filling and reinforcement.

[0040] The upper end plate is provided with standard bolt holes for positioning the first high-strength bolt; the lower end plate is provided with enlarged bolt holes for on-site connection of the second high-strength bolt. The steel lattice connector is prefabricated together with the upper segment of the diaphragm wall; the steel lattice connectors on the inner and outer sides of the diaphragm wall are connected into a whole by welding tie bars (not shown in the figure). The first high-strength bolt is pre-embedded at the bottom of the upper segment of the diaphragm wall, and the first high-strength bolt is positioned using the bolt holes on the upper end plate of the steel lattice connector and fastened with nuts.

[0041] High-strength bolts are pre-embedded at the top of the lower segment of the diaphragm wall, and these bolts are positioned using pre-embedded L-shaped angle steel. The pre-embedded high-strength bolts protrude 50–70 mm from the concrete surface, with a horizontal deviation of ±1 mm and a vertical deviation of ±2 mm. A 2–3 mm gap is left at the splicing interface between the upper and lower diaphragm wall segments, which is filled with epoxy resin to improve the joint's waterproofing and load-bearing capacity.

[0042] High-strength bolts are embedded in the concrete and welded to the reinforcing steel bars for anchorage. The other end passes through the hole in the upper plate of the steel lattice connector and is tightened with a nut. Positioning angle steel and high-strength bolts are pre-embedded in the lower segment of the diaphragm wall component.

[0043] In one embodiment of the present invention, the precast diaphragm wall has a concrete strength grade of C40 to C60, a total wall height of 15 to 35 m, and is divided into 2 to 3 segments along its height. Each segment has a diaphragm wall height of 5 to 13 m, a wall thickness of 600 to 1000 mm, and a wall width of 2000 to 3000 mm. The upper and lower segments of the diaphragm wall are assembled and connected by pre-embedded high-strength bolts and steel lattice connectors. UHPC protective plates are installed on the outside of the connectors and grouting is used for sealing.

[0044] Taking into account construction and stress requirements, the height of the steel lattice connectors is 160–200 mm, the depth is 80–120 mm, and the length of the connectors is 200–300 mm smaller than the width of the diaphragm wall to facilitate waterproofing and caulking of the vertical joints in the diaphragm wall. The spacing of the stiffening ribs is 100–200 mm, consistent with the spacing of the high-strength bolts. The thickness of the upper and lower end plates of the connectors, the thickness of the stiffening ribs, and the high-strength bolts are determined through calculation, matching the diameter and spacing of the connecting steel bars. The bearing capacity and stiffness are higher than those of the stressed steel bars, and the safety factor is not less than 1.5. To meet structural requirements, the thickness of the upper and lower end plates is not less than 16 mm, and the thickness of the stiffening ribs is not less than 12 mm.

[0045] Figure 4 and Figure 5 This is a schematic diagram of the installation process of the sliding UHPC protective panel; Figure 6 and Figure 7 This is a schematic diagram of the installation process for the push-type UHPC protective panel. The installation method for the sliding-type UHPC protective panel is as follows: First, the sliding-type UHPC protective panel is misaligned and fitted together with the steel lattice connector. Then, the sliding-type UHPC protective panel is pushed to the predetermined position and fixed to the connecting hole of the stiffening rib using C-shaped channel steel. The installation method for the push-type UHPC protective panel is as follows: The push-type UHPC protective panel is pushed forcefully to the predetermined position, and the compression and ejection of the spring pin secures it to the first or second high-strength bolt. Both types of UHPC panels have pre-drilled grouting holes and venting holes, through which sealing material is injected. Connecting holes are also provided on the inner side of the stiffening rib, allowing grout to quickly fill the entire connector cavity.

[0046] The method for assembling prefabricated diaphragm walls using the above-mentioned connection structure includes the following steps:

[0047] Precast upper and lower segments of the underground diaphragm wall, and then transport them to the construction site.

[0048] The diaphragm wall assembly process is as follows: First, the lower segment of the diaphragm wall is hoisted into the excavated trench wall. A steel beam is used to fix the lower segment to the guide wall. The upper segment of the diaphragm wall is then hoisted above the lower segment, aligned, and slowly lowered. The second high-strength bolt, pre-embedded at the top of the lower segment, is inserted into the bolt holes of the lower end plate of the steel lattice connector located at the bottom of the upper segment. Nuts and washers are used to tighten the connection. A 2-3mm gap is left between the upper and lower diaphragm wall segments, which is filled with epoxy resin 10 to improve the waterproofing and load-bearing capacity of the joint. A steel positioning pin 9 is placed in the middle of the joint interface to assist in positioning and improve the shear capacity of the joint.

[0049] After the joint is assembled, epoxy resin is applied to the outside of the steel lattice connector and the side of the UHPC plate. The UHPC protective plate is then installed on the outside of the steel lattice connector, and grout is injected into the steel lattice connector through the grouting holes reserved on the UHPC plate.

[0050] Steel clips are pre-embedded or adhered to the UHPC panels to secure them to the stiffening ribs or high-strength bolts of the steel lattice connectors, ensuring the panels do not detach during grouting. The UHPC panels have pre-drilled grouting holes and vent holes; cement mortar or high-strength grout can be used as the grouting material. Connecting holes are provided on the stiffening ribs, allowing grout to quickly fill the entire connector cavity.

[0051] It should be noted that, except for the bottom and top diaphragm wall segments located in the prefabricated diaphragm wall, the top and bottom structures of each diaphragm wall segment located between them are the same as the bottom structure of the upper diaphragm wall segment and the top structure of the lower diaphragm wall segment mentioned above, so as to achieve vertical connection.

[0052] The present invention has been described in detail above with reference to the embodiments. However, the embodiments are not intended to limit the scope of protection of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A connection structure for a prefabricated diaphragm wall, characterized in that: Includes steel lattice connectors, positioning angle steel, fasteners, and UHPC panels, among which: A groove is formed on each side of the bottom of the upper segment of the diaphragm wall, and the groove extends along the length of the upper segment of the diaphragm wall. The steel lattice connector is disposed within the groove and prefabricated together with the upper segment of the diaphragm wall. The steel lattice connector is formed by connecting a vertically arranged back plate to a parallel upper end plate and a lower end plate on the same side, so that the vertical cross-section of the formed component is a U-shape opening to one side. Multiple stiffening ribs are spaced apart in the cavity between the upper end plate and the lower end plate, and the stiffening ribs divide the cavity into multiple independent chambers. A bolt hole is formed at the position corresponding to each chamber on the upper end plate and the lower end plate. The upper end plate is fastened by a first high-strength bolt and nut pre-embedded in the upper segment of the diaphragm wall and extending from the bolt hole of the lower end plate. An L-shaped groove is formed by indenting on both sides of the top of the lower segment of the diaphragm wall, and the L-shaped groove extends along the length of the upper segment of the diaphragm wall; the positioning angle steel is prefabricated together with the lower segment of the diaphragm wall, and the two sides of the positioning angle steel cover the top edge of the lower segment of the diaphragm wall and the vertical wall of the L-shaped groove; the positioning angle steel on the top surface of the lower segment of the diaphragm wall is provided with bolt holes corresponding to the position and number of bolt holes on the lower end plate; multiple second high-strength bolts pre-embedded in the top of the lower segment of the diaphragm wall pass through the bolt holes of the positioning angle steel and the lower end plate respectively, and are locked by nuts; An L-shaped groove is also formed at the position corresponding to the L-shaped groove of the upper segment diaphragm wall and the lower segment diaphragm wall. A UHPC plate is snapped onto and covers the L-shaped grooves on the upper segment diaphragm wall and the lower segment diaphragm wall, as well as the steel lattice connector. Grouting sealing material is injected into the cavity of the steel lattice connector.

2. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: The steel lattice connectors on both sides of the bottom of the upper section of the diaphragm wall are connected together by tie bars.

3. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: A positioning pin is provided at the top of the lower segment of the diaphragm wall, and a positioning pin hole is provided at the corresponding position at the bottom of the upper segment of the diaphragm wall.

4. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: A positioning pin is provided at the bottom of the upper section of the diaphragm wall, and a positioning pin hole is provided at the corresponding position at the top of the lower section of the diaphragm wall.

5. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: The bottom surface of the lower end plate is flush with the bottom of the upper segment of the diaphragm wall; the top surface of the positioning angle steel is higher than the top surface of the lower segment of the diaphragm wall; epoxy resin is filled in the gap between the upper segment of the diaphragm wall and the lower segment of the diaphragm wall.

6. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: The space between two adjacent underground continuous walls is filled with vertical joint caulking material.

7. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: The diameter of the bolt hole on the lower end plate is larger than the diameter of the second high-strength bolt; the vertical wall of the positioning angle steel extends into the wall body of the lower segment of the diaphragm wall.

8. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: Epoxy resin is applied to the outside of the steel lattice connector and the inside of the UHPC plate. Grouting holes and venting holes are reserved on the UHPC plate.

9. The connection structure of the prefabricated diaphragm wall according to claim 1, characterized in that: The spacing between the stiffening ribs is consistent with the spacing between the first high-strength bolt and the second high-strength bolt; the stiffening ribs are provided with connecting holes to facilitate the rapid filling of the entire cavity of the steel lattice connector with grouting and sealing material.

10. A method for assembling prefabricated diaphragm walls using the connection structure of any one of claims 1-9, characterized in that, Includes the following steps: Precast the upper and lower segments of the underground diaphragm wall, and then transport them to the construction site; Construction of diaphragm walls: First, hoist the lower segment of the diaphragm wall into the excavated trench wall. Use steel beams to fix the lower segment of the diaphragm wall above the guide wall. Hoist the upper segment of the diaphragm wall above the lower segment, align it, and slowly lower it. Use positioning pins for positioning assistance. Insert the second high-strength bolt, which is pre-embedded in the top of the lower segment of the diaphragm wall, into the bolt holes of the lower end plate of the steel lattice connector located at the bottom of the upper segment of the diaphragm wall. Tighten the connection with nuts and washers. Leave a 2-3mm gap between the upper and lower segments of the diaphragm wall and fill it with epoxy resin. After the joint is assembled, epoxy resin is applied to the outside of the steel lattice connector and the side of the UHPC plate. The UHPC protective plate is then installed on the outside of the steel lattice connector, and grout is injected into the steel lattice connector through the grouting holes reserved on the UHPC plate.

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