Prefabricated steel rib plate retaining wall structure and construction method thereof

Abstract

The invention relates to a prefabricated steel rib plate retaining wall structure and a construction method thereof, and belongs to the technical field of subway open cut foundation pit retaining wall structures. The retaining wall structure comprises a steel plate main body and a self-sealing joint, wherein the self-sealing joint comprises a rigid constraint female joint, a plug-in male joint and a self-adaptive wedge-shaped water stop assembly; the rigid constraint female joint and the plug-in male joint are respectively arranged at the end parts of two adjacent steel plate main bodies; after the plug-in male connector is inserted into the rigid constraint female connector, a wedge-shaped sealing cavity with an opening at least partially facing the soil facing side is defined between the inner wall of the plug-in male connector and the inner wall of the rigid constraint female connector. The self-adaptive wedge-shaped water stop assembly is movably arranged in the wedge-shaped sealing cavity; the self-adaptive wedge-shaped water stop assembly comprises a floating type water stop sliding block and a pre-tightening positioning device. The pre-tightening positioning device is configured to provide initial wedging displacement for the floating type water stop sliding block before the action of soil pressure on the adjacent soil side, so that initial sealing specific pressure is established between the floating type water stop sliding block and the inner wall of the wedge-shaped sealing cavity.

Description

Technical Field

[0001] This invention relates to the field of retaining wall structure technology for open-cut foundation pits in subways, and particularly to a precast steel rib retaining wall structure and its construction method. Background Technology

[0002] Open-cut excavation is a common construction method in urban rail transit engineering. The process involves excavating a pit on the ground to create a closed space for the construction of the subway's main structure. In the pit support system, the capping beam, as the top structure connecting the support piles or walls, plays a crucial role in transferring the load of the support structure to the ground. A retaining wall needs to be installed on top of the capping beam. Its main function is to withstand the lateral water and soil pressure generated during the excavation process, prevent surface water from flowing back into the pit, and ensure construction safety and the stability of the surrounding environment. This retaining wall structure must meet basic requirements such as strength, stability, and waterproofing, while also considering ease of construction and space utilization efficiency.

[0003] For a long time, foundation pit retaining structures have mainly adopted traditional forms such as bored piles, diaphragm walls, or cast-in-place reinforced concrete retaining walls. Although these cast-in-place concrete structures have good overall integrity, they have inherent drawbacks such as long construction periods, large amounts of on-site wet work, and significant susceptibility to climate and environmental conditions. More seriously, these structures are usually used as one-time temporary supports and are difficult to recycle after the foundation pit is backfilled, resulting in a large amount of concrete construction waste remaining underground, causing serious resource waste and environmental pollution, which is inconsistent with the current industry trend of green construction and low-carbon circular development.

[0004] To address these issues, prefabricated steel retaining wall technology has emerged. However, in practical engineering applications, the connection and waterproof sealing between adjacent prefabricated components remain key technical bottlenecks hindering its widespread adoption. Existing connection methods mainly include on-site welding, bolted connections, and tongue-and-groove joints. While on-site welding offers high connection strength, the extensive overhead or vertical welding work at the bottom of narrow and damp foundation pits is difficult to perform and the quality is hard to guarantee. Furthermore, dismantling requires cutting and destruction, making it difficult to achieve non-destructive recycling of components. Bolted connections, under high lateral earth pressure, are prone to stress concentration around the bolt holes, leading to tearing or deformation of the components.

[0005] Currently, the mainstream tongue-and-groove joints or simple mechanical splicing methods rely primarily on pre-installed rubber waterstops for static sealing to ensure waterproofing. However, during the excavation, unloading, and backfilling of the foundation pit, the retaining wall often undergoes varying degrees of deflection or uneven settlement due to the non-uniform soil and water pressure on the adjacent side. This macroscopic deformation can easily lead to slight opening, misalignment, or widening at the joints of adjacent components. Because traditional static sealing structures lack dynamic compensation capabilities, once the change in joint gap exceeds the rebound limit of the waterstop material, the waterproofing system immediately fails, easily causing water leakage, sand inrush, or even ground subsidence due to soil erosion on the foundation pit sidewalls, posing significant safety hazards. Furthermore, in the initial stage of foundation pit backfilling or before soil pressure is established, the joints are in a relaxed state. Once exposed to rainwater or a rise in groundwater levels, leakage channels can easily form, violating the construction principle of "waterproofing first" in foundation pit engineering. Therefore, most existing adaptive sealing solutions suffer from delayed activation.

[0006] In summary, existing retaining wall technologies cannot simultaneously achieve rapid prefabrication in factories, high structural strength and durability, and long-term reliable sealing under dynamic deformation conditions. There is an urgent need for a new technical solution that is relatively simple in structure, robust, and adaptable to geotechnical conditions.

[0007] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention provides a prefabricated steel rib retaining wall structure and its construction method to solve at least some of the above-mentioned technical problems.

[0009] This invention discloses a prefabricated steel rib retaining wall structure, comprising: a steel plate body, which is configured with vertical steel plates and horizontal steel plates; a cap beam anchoring assembly, which is disposed at the lower part of the horizontal steel plates for fixing the steel plate body to the cap beam of the foundation pit; and a self-sealing joint, which is disposed at the side end of the steel plate body for connecting adjacent steel plate bodies and performing waterproof sealing. The self-sealing joint includes: a rigid constraint female joint, an insertable male joint, and an adaptive wedge-shaped water-stopping assembly. Rigidly constrained female connectors and insertable male connectors are respectively located at the ends of two adjacent steel plate bodies. The insertable male connector can be inserted into the receiving cavity of the rigidly constrained female connector. After the insertable male connector is inserted into the rigidly constrained female connector, it forms a wedge-shaped sealing cavity with an opening at least partially facing the soil side between the inner walls of the two connectors. The adaptive wedge-shaped water-stop assembly is movably placed in the wedge-shaped sealing cavity. The adaptive wedge-shaped water-stop assembly includes a floating water-stop slider and a pre-tightening positioning device. The floating water-stop slider has a sealing slope that matches the inner wall of the wedge-shaped sealing cavity and can move freely along the depth direction of the wedge-shaped sealing cavity. The pre-tightening positioning device is configured to: provide an initial wedge displacement for the floating water-stop slider before the soil pressure on the soil side is applied, so that the floating water-stop slider and the inner wall of the wedge-shaped sealing cavity establish an initial sealing pressure; after the soil pressure on the soil side is applied, the floating water-stop slider is not restricted from further displacement into the depth of the wedge-shaped sealing cavity under the drive of the soil pressure.

[0010] This invention constructs a composite sealing system combining active pre-tightening and passive reinforcement by setting a self-sealing joint on the side of the steel plate body, comprising a rigid constraint female joint, an insertable male joint, and an adaptive wedge-shaped water-stop component. Physically, this scheme utilizes the rigid constraint female joint and the insertable male joint to form a wedge-shaped sealing cavity. During construction, a pre-tightening positioning device causes the slider to initially wedge in, ensuring the joint has basic waterproofing capabilities before backfilling and during the initial low earth pressure stage (e.g., in the event of rain). Subsequently, when the foundation pit is backfilled or the earth pressure increases, the external earth pressure directly drives the slider to further deepen, utilizing the wedge-shaped force-increasing principle to convert the axial earth pressure into a huge lateral sealing extrusion force. This mechanism achieves a self-reinforcing effect of "the greater the earth pressure, the tighter the seal," effectively solving the problem of traditional passive seals easily failing under low stress conditions.

[0011] According to a preferred embodiment, the floating waterstop slider has a pressure-driven surface and a sealing contact surface, with the pressure-driven surface exposed on the soil side. Under the action of soil pressure on the soil side, the floating waterstop slider can overcome the constraint of the pre-tightening positioning device and continue to move into the depth of the wedge-shaped sealing cavity, using the incremental lateral extrusion force generated by the wedge effect to press the inner wall of the wedge-shaped sealing cavity.

[0012] The above scheme further defines the force-bearing surface and working mechanism of the floating water-stopping slider, clarifying the mechanical transmission path from earth pressure to displacement and then to compressive force, thereby ensuring the efficiency of the self-sealing function. Specifically, the pressure-bearing driving surface directly receives the horizontal earth pressure on the adjacent soil side, using it as the system's input power; the sealing contact surface, in conjunction with the guide of the wedge-shaped sealing cavity, converts the axial displacement of the slider into a normal pressing action on the inner wall of the cavity. This design utilizes the classic wedge force amplification principle; even if the increase in external earth pressure is small, through the conversion of the wedge angle, a lateral contact pressure several times greater than the axial thrust can be generated on the sealing contact surface. This scheme enables the device to establish sufficient initial sealing specific pressure in shallow areas with low earth pressure, while generating extremely high sealing pressure in deep areas with high earth pressure, effectively blocking the leakage path of high-pressure groundwater and ensuring the water-stopping effectiveness of the retaining wall throughout its entire burial depth.

[0013] According to a preferred embodiment, the cross-section of the floating water-stop slider is trapezoidal, the pressure-driven surface is the bottom surface of the trapezoid, and the sealing contact surface is the two inclined surfaces of the trapezoid; a composite water-stop strip is provided on the sealing contact surface, the composite water-stop strip including an inner layer of high-resilience rubber and an outer layer of water-swellable rubber.

[0014] This invention further solves the technical problem of inadequate sealing at the microscopic interface between rigid sliders and steel joints by defining the cross-sectional shape and surface composite material of the floating water-stop slider. The trapezoidal cross-section design maximizes the force-bearing area of ​​the pressure-driven surface while ensuring parallel fit between the sealing contact surface and the wedge-shaped cavity wall, optimizing force transmission efficiency. More importantly, the composite water-stop strip creates a double defense: the inner high-resilience rubber, with its excellent elastic modulus, rapidly generates contact stress under compression, filling macroscopic gaps; the outer water-swellable rubber, with its hydrophilic swelling properties, expands in volume upon contact with water molecules, automatically tracking and filling microscopic pores caused by steel surface roughness or processing errors. This composite structure, while ensuring mechanical compression sealing, introduces a chemical expansion sealing mechanism, significantly improving the impermeability of the joint in high-pressure fine sand or mud environments, and extending the service life of the waterproofing system.

[0015] According to a preferred embodiment, the self-sealing joint further includes an anti-deformation support assembly for limiting the sidewall deformation of the rigid constraint female joint; the rigid constraint female joint includes a load-bearing member, which is a sidewall of the receiving cavity; the anti-deformation support assembly includes a support column and an abutment member, the support column is fixed to the steel plate body, and the abutment member is connected to the end of the support column; a pressure compensation block is provided on the other side of the load-bearing member; when the soil pressure on the adjacent side is applied, the pressure compensation block applies a support force to the load-bearing member under the drive of the soil pressure, which has a component opposite to the squeezing force of the floating water-stop slider, so as to offset or reduce the bending deformation of the load-bearing member.

[0016] This invention also introduces an anti-deformation support component. For deep foundation pits with high earth pressure, the earth pressure driving effect of the pressure compensation block within the abutment cavity applies a reverse support force to the load-bearing components. This design cleverly utilizes the earth pressure itself to counteract the wedging effect generated by the earth pressure, improving the stress state of the load-bearing components, preventing joint yielding or opening deformation caused by excessive local stress, and significantly enhancing the structural load-bearing safety.

[0017] According to a preferred embodiment, an abutting cavity with an opening facing the soil side is formed between the abutting member and the load-bearing member, and the load-bearing cavity and the abutting cavity are distributed on both sides of the load-bearing member; the load-bearing cavity has a first wedge angle that is narrow inside and wide outside, and the abutting cavity has a second wedge angle that is narrow inside and wide outside.

[0018] This invention optimizes the stress distribution of the joint by defining the positional relationship between the receiving cavity and the abutment cavity, eliminating the torsional risks caused by eccentric structural stress. After the insert of the male connector is inserted into the receiving cavity, a wedge-shaped sealing cavity is further defined. The mirror-symmetric positional feature ensures that the wedge depth in the wedge-shaped sealing cavity and the wedge depth in the abutment cavity remain synchronized under earth pressure, thus making the normal pressure acting on both sides of the load-bearing member highly coincident in terms of the height of application and the distribution range. This highly symmetrical force mode eliminates the torque component on the cross-section of the load-bearing member, allowing it to bear only pure compressive stress, maximizing the compressive strength of the steel. In addition, the double-wedge structure also forms a continuous wedge-shaped force zone on the soil-facing side of the entire joint assembly, which is conducive to the smooth transition of earth pressure in the joint area, reduces local stress concentration caused by abrupt changes in stiffness, and thus improves the fatigue life and mechanical stability of the overall retaining wall structure. Furthermore, since the insert occupies part of the space in the receiving cavity, the receiving cavity and the abutment cavity need to be set with different sizes of wedge angles.

[0019] According to a preferred embodiment, the end of the insert-type male connector is constructed with an insert having a bent structure; the insert can be fitted to one of the side walls of the rigid constraint female connector, and the wedge angle of the wedge-shaped sealing cavity can be defined by setting an angle between its folded surface and the inner wall of the rigid constraint female connector; the rigid constraint female connector is constructed to constrain the lateral displacement of the floating water-stop slider by utilizing the circumferential stiffness of its cross section, and the compression of the floating water-stop slider causes the insert-type male connector and the rigid constraint female connector to form a mechanical interlock.

[0020] This invention provides a simplified implementation scheme for achieving sealing and locking using the inherent morphological characteristics of components, ensuring connection reliability while reducing manufacturing complexity. By constructing the end of the insert-type male connector as an insert with a bent structure, and utilizing the angle formed between the folded surface of the insert and the straight wall of the female connector, the complex internal bevel machining process of the female connector is cleverly eliminated, reducing prefabrication costs. Simultaneously, this scheme utilizes the circumferential stiffness of the closed section of the rigidly constrained female connector to resist the lateral compressive force generated by the slider. When the floating water-stop slider is wedged in, its compressive force forces the bent end of the insert-type male connector to achieve a tight mechanical interlock with the groove edge of the female connector. This interlocking effect strengthens with increasing earth pressure, not only achieving sealing but also effectively limiting the relative displacement of adjacent steel plate bodies in the longitudinal and transverse directions through friction and geometric hooking, preventing the joint from detaching under uneven earth pressure, and achieving a simultaneous improvement in connection strength and sealing performance.

[0021] According to a preferred embodiment, the pre-tightening positioning device includes a limiting clip or an elastic pre-tightening member disposed at the opening of the wedge-shaped sealing cavity, for maintaining the preset wedge depth of the floating water-stopping slider.

[0022] According to a preferred embodiment, the main body of the steel plate further includes a first reinforcing rib and a second reinforcing rib; the first reinforcing rib is spaced along the height direction on the soil-facing side surface of the vertical steel plate, and adopts a T-shaped steel or I-beam cross-section structure; the second reinforcing rib is located at the soil-facing angle where the vertical steel plate and the horizontal steel plate connect, and is constructed as a right-angled triangular armpit plate structure. The second reinforcing rib, together with the vertical steel plate and the horizontal steel plate, forms a rigid triangular area, and the position of the second reinforcing rib in the horizontal direction corresponds to that of the first reinforcing rib.

[0023] This invention constructs a lightweight and high-rigidity static load-bearing frame by setting specific-shaped reinforcing ribs on both the soil-facing and soil-repellent sides of the steel plate body. The first reinforcing rib on the soil-facing side adopts a T-shaped or I-beam cross-section, utilizing its high section moment of inertia to directly resist the main bending deformation of the retaining wall, ensuring the flatness of the panel. The second reinforcing rib on the soil-repellent side is designed as a right-angled triangular armhole plate, which, together with the vertical and horizontal steel plates, forms a "rigid triangular zone" that effectively converts the bending moment at the vertical cantilever end into tensile and compressive internal forces in the plane of the horizontal steel plate, suppressing horizontal displacement at the top of the wall. Furthermore, the corresponding spatial arrangement of the second and first reinforcing ribs creates a composite beam effect with continuous stiffness in the stress section of the vertical steel plates, avoiding local shear yielding of the panel due to rib misalignment, thus optimizing steel consumption while ensuring overall structural stability.

[0024] According to a preferred embodiment, the retaining wall structure further includes a capping beam anchoring assembly disposed at the lower part of the horizontal steel plate, used to fix the main body of the steel plate to the capping beam of the foundation pit; the capping beam anchoring assembly includes a plurality of capping beam clips spaced apart on the lower surface of the horizontal steel plate, the capping beam clips being adapted to be embedded in the installation groove reserved at the top of the capping beam of the foundation pit; a pre-embedded section extends from the lower part of the vertical steel plate, the pre-embedded section being embedded in the inner side of the capping beam of the foundation pit, forming a clamping structure for clamping the capping beam of the foundation pit together with the horizontal steel plate.

[0025] This invention solves the problems of difficult positioning and insufficient shear resistance of precast retaining walls on the capping beam of the foundation pit by using a design that combines capping beam clips with embedded sections. The clamping structure formed by the embedded section at the bottom of the vertical steel plate and the horizontal steel plate can utilize the self-weight of the precast components to physically hold the inner edge of the capping beam, providing an initial anti-overturning moment. The spaced capping beam clips are embedded in the grooves at the top of the capping beam, forming a series of shear keys. When the retaining wall is subjected to huge lateral earth pressure, these shear keys can directly transfer the horizontal shear force to the capping beam concrete, preventing slippage at the base of the retaining wall. This mechanical interlocking connection method not only improves the anchorage stiffness at the base of the structure but also plays a precise installation limiting role, ensuring the straightness of the assembled line of the retaining wall and meeting the stringent requirements of subway engineering for high precision and high stability of the support structure.

[0026] This invention also discloses a construction method for a precast steel rib retaining wall structure, which includes the following steps: Based on the foundation pit design parameters, the main steel plate structure and self-sealing joint components are prefabricated in the factory. The foundation pit cap beam is poured at the construction site, and a groove is reserved on its top for installation. The first precast steel rib retaining wall was hoisted and fixed to the foundation pit cap beam. Then the adjacent second precast steel rib retaining wall was hoisted and spliced ​​by the cooperation of the insert-type male connector and the rigid constraint female connector. On the soil-facing side of the joint between adjacent retaining walls, install an adaptive wedge-shaped water-stop component; operate the pre-tightening positioning device to pre-wedge the floating water-stop slider into the wedge-shaped sealing cavity to establish an initial seal; Layered backfilling of soil is carried out on the soil-adjacent side of the retaining wall; the lateral earth pressure generated by the backfill soil is used to drive the floating water-stop slider to wedge further in, thereby enhancing the joint sealing pressure. After the foundation pit project is completed, the backfill soil is removed and the components are recovered.

[0027] This invention discloses a construction method integrating factory prefabrication, rapid assembly, passive sealing, and recyclability, systematically solving the problems of long construction cycles and resource waste in traditional support technologies from a process flow perspective. The method ensures the processing accuracy of the wedge-shaped sealing cavity and various connecting parts through factory prefabrication; the on-site assembly stage utilizes insert-type connections to achieve rapid closure of components, significantly shortening the exposure time of the foundation pit. In particular, the "layered backfilling and passive locking" step cleverly utilizes the soil pressure generated by the backfilling process itself to complete the final sealing and locking of the joints, eliminating the need for additional manual tightening or grouting operations, simplifying the construction process and eliminating human error. The final dismantling and recycling step utilizes the mechanical connection characteristics between the steel plate body and the capping beam to achieve non-destructive dismantling and recycling of components, significantly reducing carbon emissions and material costs in deep foundation pit support projects, demonstrating significant economic benefits and environmental value. Attached Figure Description

[0028] Figure 1 This is an axonometric view of a retaining wall structure according to a preferred embodiment of the present invention from the perspective of the back soil side; Figure 2 This is a schematic diagram showing the fit between the cap beam anchoring component and the installation groove of the foundation pit cap beam according to a preferred embodiment of the present invention. Figure 3 This is an axonometric view of a retaining wall structure according to a preferred embodiment of the present invention from the perspective of the soil-facing side; Figure 4 This is a schematic diagram of the structure of a self-sealing joint according to a preferred embodiment of the present invention; Figure 5 This is a structural schematic diagram of a rigid constraint female connector and related components according to a preferred embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a preferred embodiment of the insert-type male connector and related components provided by the present invention; Figure 7 This is a schematic diagram of the self-sealing principle of a preferred embodiment of the self-sealing joint provided by the present invention from a top view. Figure 8 This is a structural schematic diagram of a self-sealing joint according to another preferred embodiment of the present invention from the perspective of the soil-facing side; Figure 9 This is a structural schematic diagram of a self-sealing joint according to another preferred embodiment of the present invention from the perspective of the back soil side. Figure 10 This is a schematic diagram of the structure of an insert-type male connector and related components according to another preferred embodiment of the present invention; Figure 11 This is a schematic diagram of the self-sealing principle of a self-sealing joint according to another preferred embodiment of the present invention, viewed from a top view.

[0029] List of reference numerals 100: Main steel plate; 110: Vertical steel plate; 120: Horizontal steel plate; 121: Crown beam anchoring assembly; 130: Second reinforcing rib; 140: First reinforcing rib; 150: Rigid constraint female joint; 151: Side wall surface; 152: Receiving cavity; 153: Load-bearing component; 160: Insert-type male joint; 161: Insert; 200: Anti-deformation support assembly; 210: Support column; 220: Abutment component; 230: Pressure compensation block; 240: Abutment cavity; 300: Floating water-stop slider; 310: Pressure-bearing driving surface; 320: Sealing contact surface; 400: Foundation pit crown beam; 410: Installation groove; 500: Soil-adjacent side; 600: Soil-backed side. Detailed Implementation

[0030] The following is a detailed explanation with reference to the accompanying drawings.

[0031] This invention discloses a prefabricated steel rib retaining wall structure, which includes: a steel plate body 100, a cap beam anchoring assembly 121, and a self-sealing joint.

[0032] Preferably, the steel plate body 100 serves as the core foundation load-bearing component of the entire precast steel rib retaining wall. It can evenly transfer and distribute the pressure generated on the soil side 500 during each stage of the foundation pit construction to the foundation pit capping beam 400, avoiding structural deformation caused by local stress concentration. It can also provide a precise and stable installation benchmark for the capping beam anchoring component 121 and the self-sealing joint, ensuring that all components work together. Based on the requirements of the subway open-cut foundation pit retaining wall to withstand dynamic lateral pressure, factory prefabrication, and rapid on-site installation, the material selection of the steel plate body 100 can take into account high strength, good welding performance, and ease of processing. The structural form needs to be adapted to the installation space of the foundation pit capping beam 400 and achieve a reliable connection with the foundation pit capping beam 400. The overall design needs to meet the dual requirements of standardized factory prefabrication and convenient on-site installation.

[0033] Considering that the retaining wall of the subway open-cut foundation pit needs to withstand 500 mm pressure on the adjacent soil side for a long time, may come into contact with groundwater, and needs to be welded into an integrated structure, the main body of the steel plate 100 can be made of Q355B carbon structural steel to meet the strength requirements of the retaining wall under stress. It also has excellent welding performance and can be reliably connected to other steel components through conventional welding methods such as submerged arc welding and argon arc welding. In addition, it has good processing performance and is easy to carry out factory prefabrication processes such as cutting, bending, and drilling. The main body 100 of the steel plate may include an integrated structure formed by vertically welding vertical steel plates 110 and horizontal steel plates 120. The height of the vertical steel plate 110 can be determined by the design retaining height from the top of the foundation pit capping beam 400 to the ground and the depth at which the lower part of the vertical steel plate 110 is buried in the foundation pit capping beam 400. For example, it is the sum of the retaining height above the top of the foundation pit capping beam 400 and the burial depth. The length of the horizontal steel plate 120 can be determined by the width of the foundation pit capping beam 400 to ensure that the horizontal steel plate 120 can completely cover the top of the foundation pit capping beam 400 and extend appropriately to both sides of the foundation pit capping beam 400 to provide stable support for the vertical steel plate 110. The width of the horizontal steel plate 120 is consistent with the width of the vertical steel plate 110 to avoid stress concentration during load transfer due to width differences. For example, if the designed retaining height above the top of the foundation pit capping beam 400 is 1.5~2.7m, and the depth of the lower part of the vertical steel plate 110 embedded in the foundation pit capping beam 400 is 0.3~0.5m, then the total height of the vertical steel plate 110 can be designed to be 1.8~3.0m; if the designed width of the foundation pit capping beam 400 is 0.5~0.8m, to ensure that the horizontal steel plate 120 can stably support the vertical steel plate 110 and that its edges do not exceed the allowable construction range, the length of the horizontal steel plate 120 can be designed to be 0.6~0.8m (wider than the foundation pit capping beam 400). The horizontal steel plate 120 should extend 0.05-0.1m beyond the foundation pit capping beam on both sides (the thickness of the horizontal steel plate 120 should be 0.05-0.1m). The thickness of the vertical steel plate 110 can be determined by calculating the pressure on the adjacent side of the retaining height at 500mm. The greater the lateral pressure, the greater the thickness. For example, it can be designed to be 10-14mm. The horizontal steel plate 120 needs to withstand the lateral pressure reaction force transmitted by the vertical steel plate 110 and the contact pressure between itself and the foundation pit capping beam 400. Therefore, the thickness of the horizontal steel plate 120 should be slightly greater than that of the vertical steel plate 110 to enhance its load-bearing stability. For example, it can be designed to be 12-16mm.

[0034] Preferably, the steel plate body 100 can be connected to the foundation pit capping beam 400 via a snap-fit ​​mechanism. This snap-fit ​​mechanism is formed by the portion of the vertical steel plate 110 embedded in the foundation pit capping beam 400 and the horizontal steel plate 120. The inner dimensions of the snap-fit ​​mechanism are precisely matched with the outer dimensions of the foundation pit capping beam 400, ensuring that the snap-fit ​​mechanism can be tightly locked onto the upper edge of the foundation pit capping beam 400 without any obvious gaps. The depth to which the lower part of the vertical steel plate 110 is embedded in the foundation pit capping beam 400 can be determined according to the height of the foundation pit capping beam 400 and the magnitude of the lateral pressure of the retaining soil. For example, it can be set to 1 / 3 to 1 / 2 of the height of the foundation pit capping beam 400 to ensure that the vertical steel plate 110 has sufficient anchoring force within the foundation pit capping beam 400, preventing the vertical steel plate 110 from being pulled out of the foundation pit capping beam 400 when retaining soil. For example, if the height of the foundation pit capping beam 400 is 0.9~1.0m, the depth to which the lower part of the vertical steel plate 110 is embedded in the foundation pit capping beam 400 is 0.3~0.5m. The lower surface of the horizontal steel plate 120 is completely in contact with the top surface of the foundation pit capping beam 400. To prevent the steel plate body 100 from sliding along the top surface of the foundation pit capping beam 400 during the stress process, an elastic pad is laid between the contact surface between the lower surface of the horizontal steel plate 120 and the top surface of the foundation pit capping beam 400. This elastic pad has good friction coefficient, wear resistance and aging resistance. Based on the conventional design requirements for anti-slip of the contact surface between components and concrete in subway foundation pit construction, a nitrile rubber pad can be selected. The thickness of the nitrile rubber pad can be determined based on the flatness error between the lower surface of the horizontal steel plate 120 and the top surface of the foundation pit cap beam 400, in order to fill the small gaps and ensure a tight fit. For example, it can be designed to be 3~5mm, and the thickness uniformity error should not exceed ±0.5mm, so as to avoid the horizontal steel plate 120 from tilting due to uneven pad thickness, which would affect the overall structural stability.

[0035] Preferably, a plurality of capping beam anchoring components 121 may be spaced out on the lower surface of the horizontal steel plate 120 to enhance the vertical constraint between the retaining wall and the capping beam 400 of the foundation pit. To facilitate the installation of the capping beam anchoring components 121, a corresponding installation groove 410 is reserved on the top of the capping beam 400 of the foundation pit, wherein the shape of the installation groove 410 is adapted to the anchoring components.

[0036] Preferably, to facilitate the transportation, on-site hoisting and installation, and subsequent dismantling and recycling of the steel plate body 100 after factory processing, lifting ring holes are pre-reserved on the inner side (soil-backed side 600) of the vertical steel plate 110 and lifting rings are installed thereon. The position of the lifting ring holes can be determined according to the center of gravity of the steel plate body 100. For example, it can be set at 0.2m from the top of the vertical steel plate 110. This position can ensure that the main body is balanced under force during hoisting and avoid tilting. There can be two lifting ring holes, which are symmetrically arranged along the width direction of the vertical steel plate 110. The center of symmetry coincides with the width center of the vertical steel plate 110 to ensure that the force on both sides is uniform during hoisting. The diameter of the lifting ring holes can be determined according to the diameter of the lifting ring, and is usually 1-2mm larger than the diameter of the lifting ring to facilitate the smooth installation of the lifting ring.

[0037] Preferably, to enhance structural strength, a first reinforcing rib 140 and a second reinforcing rib 130 may be respectively provided on the soil-facing side 500 and the soil-backing side 600 of the steel plate body 100.

[0038] The first reinforcing rib 140 serves as a basic strength enhancement component on the soil-facing side 500 of the main steel plate 100, and can be spaced at intervals along the height direction on the soil-facing side 500 of the vertical steel plate 110. The first reinforcing rib 140 can be made of T-shaped steel or I-beam, with its web vertically welded to the outer surface of the vertical steel plate 110 and its flanges parallel to the vertical steel plate 110, thereby forming a high-rigidity bending section that directly bears and transmits the water and soil lateral pressure on the soil-facing side 500. For example, the material of the first reinforcing rib 140 can be Q355B steel, its height can be 0.6 to 0.8 times the depth of the lower part of the vertical steel plate 110 embedded in the foundation pit cap beam 400, and its width can be 0.2 to 0.3 times its own height.

[0039] The function of the second reinforcing rib 130 is to strengthen the corner strength formed by the vertical steel plate 110 and the horizontal steel plate 120, disperse the corner stress, and prevent cracking in this stress concentration area during the retaining process. For example, the second reinforcing rib 130 can be made of Q355B steel and is a right-angled triangular steel plate. The dimensions of its right-angled sides are adapted to the thickness of the vertical steel plate 110 and the horizontal steel plate 120, as well as the corner space. The length of its right-angled sides can be 0.25 to 0.4 times the width of the foundation pit cap beam 400, and its thickness is consistent with the thickness of a portion of the horizontal steel plate 120. The right-angled sides of the second reinforcing rib 130 are connected to the upper inner side of the vertical steel plate 110 and the upper surface of the horizontal portion using double-sided fillet welds.

[0040] The core innovation of this invention lies in the connection and waterproofing system between adjacent precast steel rib retaining wall bodies, which creatively employs a passive self-sealing joint with rigid constraint function. This self-sealing joint is not a traditional mechanical linkage device, but rather an adaptive sealing device implemented using the principle of "passive earth pressure triggering" in geotechnical engineering. It mainly consists of a rigid constraint female joint 150 located at the end of the first steel plate body 100, an insertable male joint 160 located at the end of the second steel plate body 100, and an adaptive wedge-shaped water-stop component placed within the cavity formed by the two. The adaptive wedge-shaped water-stop component may include a floating water-stop slider 300 and a pre-tightening positioning device. In terms of macroscopic layout, this self-sealing joint is arranged along the entire length of the vertical steel plate 110, ensuring a complete seal from the top of the foundation pit cap beam 400 to the top of the retaining wall. It not only undertakes the physical connection and positioning functions of adjacent components, but more importantly, it undertakes the core task of converting the horizontal earth pressure on the adjacent side 500 into a joint sealing force.

[0041] Specifically, the rigid constraint female joint 150 serves as the load-bearing base and constraint body of the entire joint assembly, and its structural stability directly determines the reliability of the connection. The rigid constraint female joint 150 is a special-shaped channel steel structure made of high-strength carbon structural steel (such as Q355B steel) welded vertically to the side edge of the vertical steel plate 110 of the first steel plate body 100. To meet the mechanical requirements of rigid constraint, this special-shaped channel steel is not ordinary cold-formed thin-walled steel, but a rigid channel body with a specific structure welded from thick-walled steel plates using full-penetration first-level welds. The opening of this rigid channel body can at least partially face the soil-adjacent side 500, thus forming a rigid receiving cavity 152 with a three-sided enclosed structure. To prevent the rigid constraint female joint 150 from expanding and deforming under the action of huge horizontal wedging forces, the flange plate thickness of the channel body can be designed to be 1.2 to 1.5 times the thickness of the vertical steel plate 110, and stiffening ribs are welded on the outer side of the channel body facing away from the interface to provide strong circumferential constraint stiffness. The rigid receiving cavity 152 of the rigid constraint female connector 150 may include two side wall surfaces 151 (i.e., the inner surfaces of the flange plates on both sides of the tank), and these two side wall surfaces 151 are non-parallel. Specifically, they may be wedge-shaped guide surfaces that are narrower on the inside and wider on the outside, formed by precision machining or prefabrication and welding. The inclination angle of the wedge-shaped guide surface relative to the center line of the tank is precisely calculated, for example, it can be set between 10 and 15 degrees. This angle can ensure the smooth sliding of the floating water-stop slider 300 and generate a significant wedge-shaped force-increasing effect when subjected to force, avoiding friction self-locking failure due to excessive angle or insufficient stroke due to insufficient angle.

[0042] A plug-in male connector 160 is disposed at the end of the second steel plate body 100 in conjunction with the rigid constraint female connector 150. The plug-in male connector 160 can be vertically welded to the corresponding side of the second steel plate body 100, and its insert 161 can be inserted into the rigid groove of the rigid constraint female connector 150 in a manner opposite to the opening direction of the rigid receiving cavity 152 of the rigid constraint female connector 150. The thickness of the plug-in male connector 160 is less than the minimum clear width of the rigid receiving cavity 152 inside the rigid constraint female connector 150 to ensure that the plug-in male connector 160 can be smoothly inserted vertically into the rigid receiving cavity 152 during the hoisting and splicing stage, with sufficient assembly tolerance. When the plug-in male connector 160 inserts its insert 161 into the rigid receiving cavity 152, its insert 161 can be fitted against one of the side wall surfaces 151 of the rigid receiving cavity 152. When the insertable male connector 160 is fully inserted, it does not make direct, rigid contact with the inner wall of the rigidly constrained female connector 150, but rather is in a loose fit. At this time, a wedge-shaped sealing cavity with an inverted V-shaped cross-section is naturally formed in spatial geometry between the plate surface of the insertable male connector 160 (the side facing the soil side 500) and the wedge-shaped guide surface (inner wall) of the rigidly constrained female connector 150. The physical characteristic of this wedge-shaped sealing cavity is that its opening width is significantly larger than its bottom width, and this opening directly and unobstructedly faces the backfill soil area of ​​the soil side 500, constituting a stress window for receiving earth pressure.

[0043] As the actuating element for achieving the sealing function, the floating water-stop slider 300 is movably placed within the aforementioned wedge-shaped sealing cavity. The floating water-stop slider 300 is not a fixed component, but rather an independent, elongated solid structure. Its material can be a solid steel rod as a skeleton to provide rigidity, with external or partial composite rubber materials. Its cross-sectional shape is an isosceles trapezoid that strictly conforms to the wedge-shaped sealing cavity. The floating water-stop slider 300 has three key working surfaces: a wider bottom surface and two inclined surfaces on both sides. The wider bottom surface can be defined as the pressure-bearing driving surface 310, which directly contacts the backfill soil medium on the adjacent soil side 500 during operation, responsible for receiving horizontal earth pressure. The inclined surfaces on both sides can be defined as sealing contact surfaces 320, whose inclination angle is completely consistent with the wedge-shaped guide surface of the rigid constraint female connector 150. To achieve a leak-proof sealing effect, high-performance composite water-stop strips can be installed on the sealing contact surfaces 320 on both sides of the floating water-stop slider 300 through vulcanization bonding or dovetail groove embedding. This composite water-stop strip can adopt a two-component structure. The core is made of high-resilience EPDM ethylene propylene diene monomer rubber, ensuring resilience under long-term compression. The surface is covered with water-swellable rubber, which utilizes its water-swelling property to fill microscopic gaps, achieving double protection. Furthermore, considering the actual needs during construction, the floating water-stop slider 300 is prone to detachment or displacement under gravity before backfilling. The pre-tightening positioning device is configured to provide an initial wedging displacement for the floating water-stop slider 300 before the application of 500mm earth pressure on the adjacent side, establishing an initial sealing pressure between the floating water-stop slider 300 and the inner wall of the wedge-shaped sealing cavity. Preferably, the pre-tightening positioning device includes a limiting clip or elastic pre-tightening element disposed at the opening of the wedge-shaped sealing cavity to maintain the preset wedging depth of the floating water-stop slider 300.

[0044] Self-sealing joints achieve passive self-sealing based on a dynamic process of mechanical equilibrium and transformation. During backfilling after the foundation pit support structure is completed, the soil on the adjacent 500mm side gradually buries the joint area. At this time, the horizontal static earth pressure or active earth pressure generated by the backfill directly acts on the pressure-bearing driving surface 310 of the floating water-stop slider 300. As the soil depth increases, the horizontal thrust drives the floating water-stop slider 300 to move deeper into the wedge-shaped sealing cavity (i.e., in the direction of the back soil side 600mm). Due to the existence of the wedge geometry, the floating water-stop slider 300 is constrained by the wedge-shaped guide surfaces on both sides of the rigid constraint female joint 150 during axial advancement. According to the principle of force decomposition, the enormous axial earth pressure is decomposed into a compressive force perpendicular to the sealing contact surface 320 on the inclined plane. At this time, the rigid constraint female joint 150 plays a crucial circumferential constraint function; its thick-walled groove acts like a powerful "clamp," attempting to open the joint's compressive force through its own tensile stress balance, thereby forcing this enormous force to act entirely on the composite water-stop strip. The greater the earth pressure, the deeper the slider is embedded, and the more tightly the composite water-stop strip is compressed, thus achieving an adaptive effect where the sealing performance automatically improves with the increase of external load. This design not only cleverly utilizes earth pressure, which is originally considered an unfavorable factor, as a sealing driving force, but also effectively prevents the separation of adjacent steel plate bodies 100 due to wedging effect through the circumferential constraint mechanism of the rigid constraint female joint 150, ensuring the integrity and water-stopping reliability of the precast steel rib retaining wall structure.

[0045] Preferably, to prevent local deformation of the rigid constraint female connector 150 and / or the insertion male connector 160 due to pressure on both sides during the displacement of the floating water-stop slider 300 into the depth of the wedge-shaped sealing cavity, the self-sealing joint may also be provided with an anti-deformation support assembly 200, which is used to provide lateral support for the rigid constraint female connector 150 and / or the insertion male connector 160. More preferably, the anti-deformation support assembly 200 can be used in particular to support the component belonging to the side wall 151 of the rigid constraint female connector 150 that is isolated and not in contact with the insertion piece 161 of the insertion male connector 160. This is because the component lacks support from the insertion male connector 160 and is more easily deformed by pressure. This component can be referred to as the load-bearing component 153. The anti-deformation support assembly 200 can provide lateral support to the load-bearing component 153 in various forms to prevent deformation or even breakage of the load-bearing component 153.

[0046] According to one embodiment, the anti-deformation support assembly 200 may include a support column 210 with one end connected to a first reinforcing rib 140, wherein the support column 210 may be connected to the first reinforcing rib 140 on the steel plate body 100 closest to the rigid constraint female joint 150, so as to utilize the first reinforcing rib 140 to provide support force. The other end of the support column 210 may be directly connected to the load-bearing member 153 to provide lateral support force.

[0047] According to another embodiment, the anti-deformation support assembly 200 may include an assembly consisting of an abutment member 220 and a pressure compensation block 230, wherein the abutment member 220 may be configured with the load-bearing member 153 to form a wedge-shaped structure similar to a wedge-shaped sealing cavity to form an abutment cavity 240, so that the pressure compensation block 230, which is similar to the structure of a floating water-stop slider 300, can be placed into the abutment cavity 240 and provide lateral support force to the load-bearing member 153 under the action of horizontal earth pressure.

[0048] More preferably, the two embodiments described above can be combined so that the other end of the support column 210 can be connected to the outside of the abutment 220, thereby forming a relatively stable self-sealing structure.

[0049] Figure 1 A back-facing (600° back-soil side) is shown as an axonometric view of the retaining wall structure provided in the first embodiment of the present invention. Figure 1 As shown, viewed from the soil-backed side 600, the steel plate body 100 exhibits its back reinforcement system. Several second reinforcing ribs 130 are provided in the inner angle region where the vertical steel plate 110 and the horizontal steel plate 120 connect. These second reinforcing ribs 130 have a right-angled triangular plate structure, with their right-angled sides welded to the inner surface of the vertical steel plate 110 and the lower surface of the horizontal steel plate 120, respectively. The horizontal positions of the second reinforcing ribs 130 correspond one-to-one with the first reinforcing ribs 140 on the soil-adjacent side 500, forming a through-type stiffening system. The second reinforcing ribs 130 are constructed as right-angled triangular armpit plates, which, together with the vertical steel plate 110 and the horizontal steel plate 120, form a rigid triangular region. This region utilizes the geometric stability of the triangle to transform the cantilever bending moment on the vertical steel plate 110 into tensile and compressive stresses in the plane of the horizontal steel plate 120, thereby effectively suppressing displacement at the top of the wall. Furthermore, the second reinforcing rib 130 and the first reinforcing rib 140 on the soil-adjacent side 500 are arranged in a coplanar, back-to-back configuration. This arrangement results in the stress-bearing section of the vertical steel plate 110 forming a composite section resembling a "cross" or "I" shape, ensuring the continuity of stiffness in the wall thickness direction and avoiding local shear deformation caused by rib misalignment.

[0050] Figure 2 A schematic diagram showing the fit between the capping beam anchoring assembly 121 and the foundation pit capping beam 400 in this embodiment is shown. Figure 2As shown, several downward-protruding cap beam anchoring components 121 are welded to the lower surface of the horizontal steel plate 120. A matching installation groove 410 is pre-reserved in the top concrete structure of the foundation pit cap beam 400. The steel plate body 100 rests on the foundation pit cap beam 400 via the horizontal steel plate 120, and the cap beam anchoring components 121 are embedded in the installation groove 410, forming a mechanical interlocking connection. The lower extension of the vertical steel plate 110 is embedded inside the foundation pit cap beam 400, achieving double fixation at the base of the retaining wall.

[0051] Figure 3 The image shows a frontal (500mm from the soil side) isometric view of the retaining wall structure of this embodiment. Figure 3 As shown, the main body of the retaining wall structure is a steel plate body 100, which includes vertically arranged vertical steel plates 110 and horizontal steel plates 120 vertically welded to the vertical steel plates 110. On the soil-facing surface 500 of the vertical steel plates 110, several first reinforcing ribs 140 are arranged vertically at intervals. The first reinforcing ribs 140 have a T-shaped cross-section and extend from bottom to top. On the left and right edges of the steel plate body 100, joint assemblies for connecting adjacent components are respectively provided, one side being a rigid constraint female joint 150 and the other side being an insert-type male joint 160. In addition, the rigid constraint female joint 150 also integrates an anti-deformation support assembly 200 and a floating water-stop slider 300 (the interior is not fully shown in the figure). All components together constitute a complete prefabricated unit.

[0052] Figure 4 A partially enlarged structural schematic diagram of the self-sealing joint in this embodiment is shown. (See attached diagram.) Figure 4 As shown, the joint is in the assembled state. The rigid constraint female joint 150 is located at the end of the left steel plate body 100, and the insertable male joint 160 (partially obscured in the figure, located inside) is inserted into it. A floating water-stop slider 300 is installed in the receiving cavity 152 formed by the rigid constraint female joint 150 and the insertable male joint 160. At the same time, in order to prevent the sidewall of the rigid constraint female joint 150 from deforming, an anti-deformation support assembly 200 is provided on the outside of the rigid constraint female joint 150. The anti-deformation support assembly 200 consists of a support column 210 welded to the panel, an abutment member 220 connected to the end of the support column 210, and a pressure compensation block 230 placed in the abutment cavity 240. The load-bearing member 153 is located between the floating water-stop slider 300 and the pressure compensation block 230.

[0053] Figure 5 An exploded structural diagram of the rigidly constrained female connector 150 and related components is shown (without the male connector inserted). Figure 5As shown, the rigid constraint female connector 150 is welded from multiple vertical steel plates 110 to form an outwardly opening receiving cavity 152. The inner wall of the receiving cavity 152 is defined as a side wall surface 151, which has an inclined angle that is narrower inside and wider outside. On one side of the rigid constraint female connector 150, the support column 210 and the abutment member 220 form an independent support structure. An abutment cavity 240 is formed between the abutment member 220 and the load-bearing member 153 of the rigid constraint female connector 150. The abutment cavity 240 is shaped like an inverted V, and its opening also faces the soil-adjacent side 500. Figure 5 The plate (load-bearing member 153) in the middle of the rigid constraint female joint 150 is a cantilever structure. The receiving cavity 152 and the abutting cavity 240, with the load-bearing member 153 as the central axis, form a "mirror-symmetrical double-wedge cavity structure" in spatial geometry. The receiving cavity 152 has a first wedge angle that is narrower inside and wider outside, while the abutting cavity 240 has a second wedge angle that is narrower inside and wider outside. This geometric feature is not only for accommodating the slider, but more importantly, for creating conditions for subsequent mechanical equilibrium. The load-bearing member 153, as the common sidewall of the two cavities, has two sidewalls 151 that are both load-bearing surfaces. This construction presupposes that it will be under bidirectional clamping stress in operation, rather than unidirectional bending, thus compensating for its weakness in stiffness as a cantilever member.

[0054] Figure 6 A schematic diagram of the insert-type male connector 160 and related components is shown. Figure 6 As shown, the insert-type male connector 160 is welded to the other end of the steel plate body 100. Its core feature lies in the insert 161 at the end. In this embodiment, the insert 161 is constructed as a "J"-shaped or "L"-shaped bent plate structure, with its bending direction facing inwards. The plate surface of the insert 161 is flat, providing a straight inner wall boundary for the sealing cavity after insertion. A non-tight clearance fit is used between the insert-type male connector 160 and the rigid constraint female connector 150. A specific cavity-forming gap is reserved between the design thickness of the insert 161 and the opening width of the receiving cavity 152. This gap is not a manufacturing error, but rather to force a physical space between the back side of the insert 161 and the inner wall of the receiving cavity 152 after insertion, in order to form... Figure 7 The wedge-shaped sealing cavity is shown. This design ensures that regardless of the construction precision, the sealing cavity will inevitably form as long as the insert male connector 160 is inserted, demonstrating the structure's tolerance to construction errors.

[0055] Figure 7 A schematic diagram of the self-sealing principle of the self-sealing joint is shown from a top-down view. (For example...) Figure 7The diagram illustrates the internal stress state of the joint. The soil pressure at the soil-contact side 500 acts simultaneously on the pressure-driven surface 310 of the floating water-stop slider 300 and the bottom surface of the pressure compensation block 230. The floating water-stop slider 300 is located between the insert-type male connector 160 and the load-bearing member 153; the pressure compensation block 230 is located between the load-bearing member 153 and the abutment member 220. The single-line dashed arrows in the diagram represent the lateral compressive force generated during the wedging process of the slider, while the dotted-line dashed arrows represent the external soil pressure driving force. When the soil pressure at the soil-contact side 500 is applied, the floating water-stop slider 300 generates a leftward lateral compressive force on the load-bearing member 153, while the pressure compensation block 230 generates a rightward lateral supporting force on the load-bearing member 153. These two forces form a pair of opposing supporting force systems on the load-bearing member 153. This means that when the pressure compensation block 230 presses against the load-bearing member 153 under earth pressure, it can effectively resist the lateral compressive force applied by the floating water-stop slider 300, thereby significantly reducing the bending deformation of the load-bearing member 153 and preventing it from yielding or opening. This feature enables the rigid constraint female joint 150 to withstand lateral wedge forces far exceeding its single-sided cantilever strength without excessively increasing the wall thickness, achieving a balance between lightweight and high load-bearing capacity.

[0056] Figure 8 A schematic diagram of the self-sealing joint provided in the second embodiment of the present invention is shown from a 500-degree angle on the soil-facing side. (See diagram below.) Figure 8 As shown, the rigid constraint female connector 150 can be configured as a slot structure directly welded to the end of the steel plate body 100. An insertable male connector 160 is inserted into this slot. The floating water-stop slider 300 is placed in the V-shaped gap (receiving cavity 152) formed by the two, with its outer surface (pressure-driven surface 310) directly exposed to the soil-facing side 500. A second reinforcing rib 130 is provided on the soil-backing side 600. Similar to the first embodiment, this embodiment also includes a pre-tightening positioning device (such as a limiting clip) within the wedge-shaped sealing cavity to hold the floating water-stop slider 300 in a preset position with an initial sealing pressure before backfilling.

[0057] Figure 9 A schematic diagram of the self-sealing joint of the second embodiment is shown from a 600-degree angle on the back side of the soil. (See diagram below.) Figure 9 As shown, viewed from the back side 600, the rigid constraint female connector 150 wraps around the end of the insert male connector 160. The figure clearly shows the overlapping relationship between the insert male connector 160 and the female connector, as well as the arrangement of the second reinforcing rib 130 on the back.

[0058] Figure 10 A schematic diagram of the insert-type male connector 160 in the second embodiment is shown. (See attached diagram.) Figure 10As shown, the end of the insert-type male connector 160 is cold-bent to form an insert 161 with an acute angle. The folded-back surface of the insert 161 is inclined, and when it is inserted vertically into a straight slot, the inclined surface naturally forms one side wall 151 of the wedge-shaped cavity.

[0059] Figure 11 A schematic diagram of the self-sealing principle of the second embodiment of the self-sealing joint, viewed from above, is shown. Figure 11 The diagram illustrates the internal mechanical model of the self-sealing joint. The bent end of the insert-type male connector 160 hooks onto the edge of the rigidly constrained female connector 150. A floating water-stopping slider 300 is positioned between them. Earth pressure (represented by dotted arrows) pushes the slider into place, and the sealing contact surface 320 of the slider presses against the bent surface of the male connector and the inner wall of the female connector, respectively (in the direction of the dotted arrows).

[0060] In the second embodiment, the formation of the wedge-shaped sealing cavity does not entirely depend on the irregular machining of the female connector, but is achieved by utilizing the structural bending angle of the insert 161 at the end of the insert-type male connector 160. The angle formed between the folded surface of the insert 161 and the straight wall of the rigidly constrained female connector 150 directly defines the wedge angle of the sealing cavity. This indicates that the wedge function is integrated into the plate design of the male connector. Figure 11 When the floating water-stop slider 300 is wedged in, the lateral compressive force it generates attempts to pry open the rigid constraint female connector 150. At this time, the bottom plate (the part connecting the left and right side walls) of the rigid constraint female connector 150 is in a tensile state. The rigid constraint female connector 150 uses the circumferential stiffness of its cross section to passively constrain the lateral displacement of the slider. At the same time, the squeezing of the slider on the insert male connector 160 forces the end hook point of the insert male connector 160 to form a tighter mechanical interlock with the groove of the female connector, preventing the self-sealing joint from disengaging under earth pressure.

[0061] The present invention also discloses a construction method for the aforementioned precast steel rib retaining wall structure, which includes the following steps: Based on the foundation pit design parameters, the main steel plate 100 and self-sealing joint assembly are prefabricated in the factory. A 400mm capping beam for the foundation pit is poured at the construction site, and an installation groove 410 is reserved on its top. The first precast steel rib retaining wall was hoisted and fixed to the foundation pit cap beam 400. Then the adjacent second precast steel rib retaining wall was hoisted and spliced ​​by the cooperation of the insert-type male connector 160 and the rigid constraint female connector 150. At the joint of adjacent retaining walls, on the soil-adjacent side 500, an adaptive wedge-shaped water-stop component is installed; the pre-tightening positioning device is operated so that the floating water-stop slider 300 is pre-wedged into the wedge-shaped sealing cavity to establish an initial seal; The retaining wall is backfilled in layers on the 500mm side adjacent to the soil. The lateral earth pressure generated by the backfill soil drives the floating water-stop slider 300 to wedge further in, enhancing the joint sealing pressure. After the foundation pit construction is completed, the backfill soil is excavated and the components are recovered. It should be noted that the above specific embodiments are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. A precast steel ribbed retaining wall structure, characterized by, It includes: A steel plate body (100) configured with vertical steel plates (110) and horizontal steel plates (120); A self-sealing joint provided at the side end of the steel plate body (100) for connecting adjacent steel plate bodies (100) and performing waterproof sealing, the self-sealing joint comprising: a rigid constraint female joint (150), an insert male joint (160), and a self-adaptive wedge-shaped water stop assembly; wherein The rigid constraint female joint (150) and the insert male joint (160) are respectively provided at the end of the two adjacent steel plate bodies (100), and the insert male joint (160) can be inserted into the receiving cavity (152) of the rigid constraint female joint (150); After the insert male joint (160) is inserted into the rigid constraint female joint (150), a wedge-shaped sealing cavity with an opening at least partially facing the soil side (500) is formed between the inner walls of the two joints; the self-adaptive wedge-shaped water stop assembly is movably arranged in the wedge-shaped sealing cavity; The self-adaptive wedge-shaped water stop assembly comprises a floating water stop slider (300) and a pre-tightening positioning device; the floating water stop slider (300) has a sealing slope matched with the inner wall of the wedge-shaped sealing cavity and can freely displace along the depth direction of the wedge-shaped sealing cavity; The pre-tightening positioning device is configured to provide an initial wedge displacement for the floating water stop slider (300) before the soil pressure of the soil side (500) acts, so that the floating water stop slider (300) establishes an initial sealing specific pressure with the inner wall of the wedge-shaped sealing cavity; after the soil pressure of the soil side (500) acts, the floating water stop slider (300) is not limited to further displace to the deep part of the wedge-shaped sealing cavity under the driving of the soil pressure.

2. The precast steel ribbed sheet retaining wall structure according to claim 1, wherein, The floating water stop slider (300) has a pressure-driven surface (310) and a sealing contact surface (320), the pressure-driven surface (310) is exposed to the soil side (500); under the action of the soil pressure of the soil side (500), the floating water stop slider (300) can continue to move to the deep part of the wedge-shaped sealing cavity by overcoming the constraint of the pre-tightening positioning device, and the incremental lateral extrusion force generated by the wedge effect is used to press the inner wall of the wedge-shaped sealing cavity.

3. The precast steel ribbed sheet retaining wall structure according to claim 2, wherein, The cross section of the floating water stop slider (300) is trapezoidal, the pressure-driven surface (310) is the bottom surface of the trapezoid, and the sealing contact surface (320) is the two side slopes of the trapezoid; a composite water stop rubber strip is arranged on the sealing contact surface (320), and the composite water stop rubber strip comprises high-resilience rubber in the inner layer and water-swelling rubber in the surface layer.

4. The precast steel ribbed sheet retaining wall structure according to claim 2, wherein, The self-sealing joint further comprises an anti-deformation support assembly (200) for limiting the deformation of the side wall of the rigid constraint female joint (150); the rigid constraint female joint (150) comprises a bearing piece (153), which is a side wall of the receiving cavity (152); the anti-deformation support assembly (200) comprises a support column (210) and an abutting piece (220), the support column (210) is fixed on the steel plate body (100), and the abutting piece (220) is connected to the end of the support column (210); a pressure compensation block (230) is arranged on the other side of the bearing piece (153); when the earth pressure acts on the soil side (500), the pressure compensation block (230) applies a support force to the bearing piece (153) under the driving of the earth pressure, which has a reverse component in the direction of the extrusion force of the floating water stop sliding block (300), so as to offset or reduce the bending deformation of the bearing piece (153).

5. The precast steel ribbed sheet retaining wall structure according to claim 4, wherein, An abutting cavity (240) with an opening facing the soil side (500) is formed between the abutting piece (220) and the bearing piece (153), and the receiving cavity (152) and the abutting cavity (240) are arranged on both sides of the bearing piece (153); the receiving cavity (152) has a first wedge angle with a narrow inner part and a wide outer part, and the abutting cavity (240) has a second wedge angle with a narrow inner part and a wide outer part.

6. The precast steel ribbed sheet retaining wall structure according to claim 5, wherein, The end of the plug-in male joint (160) is configured with an insert (161) with a bending structure; the insert (161) can be arranged in close contact with one of the side walls (151) of the rigid constraint female joint (150), and the return surface thereof and the inner wall of the rigid constraint female joint (150) can define the wedge angle of the wedge-shaped sealing cavity by setting an included angle; the rigid constraint female joint (150) is configured to constrain the lateral displacement of the floating water stop sliding block (300) by using the circumferential rigidity of its cross section, and the extrusion of the floating water stop sliding block (300) causes the plug-in male joint (160) and the rigid constraint female joint (150) to form mechanical interlocking.

7. The precast steel ribbed panel retaining wall structure according to claim 1, wherein, The pre-tightening positioning device comprises a limiting clamp or an elastic pre-tightening piece arranged at the opening of the wedge-shaped sealing cavity, for maintaining the preset wedge depth of the floating water stop sliding block (300).

8. The precast steel ribbed panel retaining wall structure according to claim 1, wherein, The steel plate body (100) further comprises a first reinforcing rib plate (140) and a second reinforcing rib plate (130); the first reinforcing rib plate (140) is arranged on the surface of the soil side (500) of the vertical steel plate (110) in the height direction, and adopts a T-shaped steel or I-shaped steel cross section structure; the second reinforcing rib plate (130) is arranged at the back-to-soil side (600) of the joint of the vertical steel plate (110) and the horizontal steel plate (120), and is configured as a straight angle triangular armpit plate structure, the second reinforcing rib plate (130), the vertical steel plate (110) and the horizontal steel plate (120) together form a rigid triangular area, and the position of the second reinforcing rib plate (130) in the horizontal direction corresponds to the first reinforcing rib plate (140).

9. The precast steel ribbed panel retaining wall structure according to claim 1, wherein, It also includes a crown beam anchoring assembly (121) arranged at the lower part of the horizontal steel plate (120) for fixing the steel plate body (100) to the foundation pit crown beam (400); the crown beam anchoring assembly (121) includes a plurality of crown beam buckles arranged at the lower surface of the horizontal steel plate (120), which are adapted to be embedded into the installation groove (410) reserved at the top of the foundation pit crown beam (400); the lower part of the vertical steel plate (110) extends a pre-buried section which is embedded into the inner side of the foundation pit crown beam (400) and forms a clamping structure with the horizontal steel plate (120) to clamp the foundation pit crown beam (400).

10. A method of constructing a precast steel ribbed retaining wall structure, characterised in that, It includes the following steps: According to the design parameters of the foundation pit, the steel plate body (100) and the self-sealing joint assembly are prefabricated in the factory; Pour the foundation pit crown beam (400) at the construction site, and reserve the installation groove (410) at the top thereof; Lift the first prefabricated steel rib plate retaining wall, fix it to the foundation pit crown beam (400), then lift the adjacent second prefabricated steel rib plate retaining wall, and complete the splicing by inserting the male joint (160) into the rigid constraint female joint (150); Install the self-adaptive wedge-shaped water stop assembly at the soil side (500) of the splicing part of the adjacent retaining walls; operate the pre-tightening positioning device to make the floating water stop sliding block (300) pre-wedge into the wedge-shaped sealing cavity to establish the initial sealing; Perform layered earthwork backfilling on the soil side (500) of the retaining wall; use the lateral earth pressure generated by the backfilling soil to drive the floating water stop sliding block (300) to wedge further and enhance the joint sealing specific pressure; After the completion of the foundation pit project, the backfilling soil is excavated and the components are recycled.

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