Pre-paved ECC anti-crack and anti-seepage protection structure and underground station construction method

Abstract

The invention discloses a pre-paved ECC anti-crack and anti-seepage protection structure and an underground station construction method. The pre-paved ECC anti-crack and anti-seepage protection structure structurally comprises a bottom plate structure layer, an underground second-layer side wall structure, an underground first-layer side wall structure and a top plate structure layer. The construction method comprises the following steps that in the range of the bottom plate, the ECC anti-crack and anti-seepage protection layer is pre-laid on the construction bottom plate, the bottom plate top prefabricated ECC anti-crack protection plate is installed, and the bottom plate structure layer is constructed; in the range of the second underground layer, an ECC anti-cracking and anti-seepage protection layer is pre-paved on the side wall of the second underground layer, and a side wall structure of the second underground layer is constructed; constructing a middle plate structure; in the range of the first underground layer, a first underground layer side wall pre-paved ECC anti-cracking and anti-seepage protection layer is constructed, and a first underground layer side wall structure is constructed; and within the range of the top plate, a top plate bottom prefabricated ECC anti-cracking protection plate is installed, a top plate structure layer is constructed, and a self-compacting ECC anti-cracking anti-seepage protection layer is constructed at the top plate. The anti-cracking and anti-seepage performance of the urban rail underground station under the open excavation method is remarkably improved, the structural design is optimized, the engineering cost is reduced, and the construction efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of urban rail underground stations, and in particular relates to a pre-laid ECC anti-cracking and anti-seepage protection structure and an underground station construction method. Background Art

[0002] As underground projects, urban rail underground stations are exposed to complex geological and hydrological environments for extended periods, making them susceptible to structural cracking and other factors, leading to water leakage. Cracks in station structures can develop due to geological subsidence, concrete shrinkage, or external loads, creating pathways for groundwater infiltration. Water leakage not only impacts station operational safety but also accelerates structural corrosion, increasing maintenance costs. To meet the crack resistance requirements for urban rail underground station structures, even when the exterior walls and roof and floor slabs meet the required load-bearing capacity, component cross-sectional dimensions and reinforcement are continuously increased to limit crack width, increasing project costs. Summary of the Invention

[0003] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a pre-laid ECC anti-cracking and anti-seepage protection structure and an underground station construction method.

[0004] The technical solution of the present invention is: a pre-laid ECC anti-cracking and anti-seepage protection structure, the structure of which includes: The bottom plate structure layer, the outer side of the bottom plate structure layer is provided with a pre-laid ECC anti-crack and anti-seepage protective layer, and the top of the bottom plate is provided with a prefabricated ECC anti-crack protective plate in the bottom plate structure layer; The underground second floor side wall structure has an ECC anti-cracking and anti-seepage protective layer pre-paved on the outside of the underground second floor side wall structure; The underground first floor side wall structure, the outer side of the underground first floor side wall structure is provided with an underground first floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer; The top plate structural layer, a self-compacting ECC anti-cracking and anti-seepage protective layer is arranged on the outside of the top plate structural layer, and a prefabricated ECC anti-cracking protective plate is arranged on the bottom of the top plate in the top plate structural layer.

[0005] Furthermore, the prefabricated ECC anti-cracking protection plate on the top of the bottom plate is prefabricated in the factory, the prefabricated ECC anti-cracking protection plate on the top of the bottom plate is provided with concave and convex grooves arranged in a crisscross pattern, a steel mesh is provided inside the prefabricated ECC anti-cracking protection plate on the top of the bottom plate, and protruding steel bars are provided around the prefabricated ECC anti-cracking protection plate on the top of the bottom plate.

[0006] Furthermore, a U-shaped steel bar is provided on the end surface of the prefabricated ECC anti-crack protection plate on the top of the bottom plate.

[0007] Furthermore, in the base plate range, the order of component setting from bottom to top is: base plate plain concrete cushion layer, base plate waterproof layer, base plate pre-laid ECC anti-cracking and anti-seepage protective layer, base plate structural layer, and base plate top prefabricated ECC anti-cracking protective plate.

[0008] Furthermore, in the area of ​​the second underground floor, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure, leveling layer, second underground floor waterproofing membrane, pre-laid ECC anti-cracking and anti-seepage protective layer on the second underground floor side wall, and second underground floor side wall structure.

[0009] Furthermore, in the underground first floor, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure, leveling layer, underground first floor waterproof membrane, underground first floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer, and underground first floor side wall structure.

[0010] Furthermore, in the top plate range, the order of component setting from bottom to top is: prefabricated ECC anti-cracking protection plate at the bottom of the top plate, top plate structural layer, self-compacting ECC anti-cracking and anti-seepage protection layer at the top plate, top plate waterproof layer, top plate waterproof isolation layer, and top plate fine stone concrete protection layer.

[0011] Furthermore, the ECC anti-cracking and anti-seepage protective layer pre-paved on the side wall of the second underground floor is constructed on the waterproof membrane of the second underground floor by a spraying process or a coating process.

[0012] A construction method for an underground station with a pre-laid ECC anti-cracking and anti-seepage protective structure comprises the following steps: A. In the base plate area, pre-lay the ECC anti-crack and anti-seepage protective layer on the base plate, install the prefabricated ECC anti-crack protective plate on the top of the base plate, and construct the base plate structural layer; B. In the area of ​​the second underground floor, pre-lay the ECC anti-cracking and anti-seepage protective layer on the side walls of the second underground floor, and construct the side wall structure of the second underground floor; C. Construction of plate structure; D. In the underground first floor area, pre-lay the ECC anti-cracking and anti-seepage protective layer on the underground first floor side wall, and construct the underground first floor side wall structure; E. In the top plate area, install the prefabricated ECC anti-crack protection plate at the bottom of the top plate, construct the top plate structural layer, and construct the self-compacting ECC anti-crack and anti-seepage protection layer at the top plate.

[0013] The beneficial effects of the present invention are as follows: The present invention pre-lays an ECC protective layer on key locations such as the bottom plate, side walls and top plate. The crack width can be controlled at 50-100um, which is much lower than the traditional 200um. This greatly improves the impermeability and corrosion resistance, prevents groundwater infiltration, and ensures the safety of station operations.

[0014] Under the premise of meeting the stress requirements, the present invention optimizes the thickness and reinforcement amount of the bottom plate, side wall and top plate, thereby significantly reducing the project cost.

[0015] The invention is easy and efficient to construct, has the characteristics of self-compacting, no need for vibration or spraying, and can be applied. After reaching a certain strength after construction, subsequent construction can be carried out, shortening the construction period, and eliminating temporary side wall baffles, reducing construction difficulty and cost.

[0016] The present invention significantly improves the anti-cracking and anti-seepage performance of urban rail underground stations under the open-cut method, optimizes structural design, reduces engineering costs, improves construction efficiency, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-section of an underground station with pre-laid ECC anti-cracking and anti-seepage protective layer; Figure 2 Detailed layout of the station floor in the present invention; Figure 3 Detailed drawing of pre-laid waterproof membrane outside the side wall of the second underground floor in the present invention; Figure 4 This is a detailed layout of the components on the side walls of the second underground floor of the present invention; Figure 5 Detailed drawing of pre-laid waterproof membrane outside the side wall of the underground first floor in the present invention; Figure 6 This is a detailed layout of the components on the side wall of the underground first floor of the present invention; Figure 7 Detailed layout of the station roof in the present invention; Figure 8 Detailed diagram of the prefabricated ECC anti-crack protection plate on the top of the bottom plate and the prefabricated ECC anti-crack protection plate on the bottom of the top plate in the present invention; in: 1. Plain concrete cushion layer of the bottom slab; 2. Waterproof layer of the bottom slab; 3. ECC anti-crack and anti-seepage protective layer pre-paved on the bottom slab; 4. Structural layer of the bottom slab; 5. Prefabricated ECC anti-crack protective plate on the top of the bottom slab; 6. Construction joints on both sides of the bottom slab; 7. Foundation pit retaining structure; 8. Leveling layer; 9. Waterproof membrane of the second underground floor; 10. Fixing nails; 11. ECC anti-crack and anti-seepage protective layer pre-paved on the side wall of the second underground floor; 12. Side wall structure of the second underground floor; 13. Construction joint on the top of the side wall of the second underground floor; 14. Structural column of the second underground floor; 15. Plate structure; 16. Construction joints on both sides of the middle plate; 17. Underground floor waterproofing membrane; 18. Pre-laid ECC anti-cracking and anti-seepage protective layer on the side walls of the underground floor; 19. Underground floor side wall structure; 20. Construction joint on the top of the side wall of the underground floor; 21. Underground floor structural column; 22. Prefabricated ECC anti-cracking protective plate at the bottom of the top plate; 23. Top plate structural layer; 24. Self-compacting ECC anti-cracking and anti-seepage protective layer at the top plate; 25. Top plate waterproof layer; 26. Top plate waterproof isolation layer; 27. Top plate fine stone concrete protective layer. DETAILED DESCRIPTION

[0018] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments: like Figures 1 to 8 As shown, a pre-laid ECC anti-cracking and anti-seepage protection structure, the structure of which includes: The bottom plate structure layer 4, the bottom plate pre-laid ECC anti-crack and anti-seepage protective layer 3 is set on the outside of the bottom plate structure layer 4, and the bottom plate top prefabricated ECC anti-crack protective plate 5 is set in the bottom plate structure layer 4; The underground second floor side wall structure 12, the outer side of the underground second floor side wall structure 12 is provided with an underground second floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer 11; The underground first floor side wall structure 19, the outer side of the underground first floor side wall structure 19 is provided with an underground first floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer 18; The top plate structural layer 23 has a top plate self-compacting ECC anti-cracking and anti-seepage protective layer 24 arranged on the outside of the top plate structural layer 23 and a top plate bottom prefabricated ECC anti-cracking protective plate 22 arranged in the top plate structural layer 23 .

[0019] The prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate is prefabricated in the factory. The prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate is provided with concave and convex grooves arranged in a crisscross pattern. A steel mesh is provided inside the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate. Protruding steel bars are provided around the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate.

[0020] A U-shaped steel bar is provided on the end surface of the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate.

[0021] In the base plate range, the order of component setting from bottom to top is: base plate plain concrete cushion layer 1, base plate waterproof layer 2, base plate pre-laid ECC anti-cracking and anti-seepage protective layer 3, base plate structural layer 4, and base plate top prefabricated ECC anti-cracking protective plate 5.

[0022] In the area of ​​the second underground floor, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure 7, leveling layer 8, underground second floor waterproof membrane 9, pre-laid ECC anti-cracking and anti-seepage protective layer 11 on the side wall of the second underground floor, and underground second floor side wall structure 12.

[0023] In the underground first floor, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure 7, leveling layer 8, underground first floor waterproof membrane 17, underground first floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer 18, underground first floor side wall structure 19.

[0024] In the top plate area, the order of component setting from bottom to top is: prefabricated ECC anti-cracking protection plate 22 at the bottom of the top plate, top plate structural layer 23, self-compacting ECC anti-cracking and anti-seepage protection layer 24 at the top plate, top plate waterproof layer 25, top plate waterproof isolation layer 26, and top plate fine stone concrete protection layer 27.

[0025] The ECC anti-cracking and anti-seepage protective layer 11 pre-paved on the side wall of the second underground floor is constructed on the waterproof membrane 9 of the second underground floor by a spraying process or a coating process.

[0026] Specifically, such as Figure 2 As shown, the ECC anti-cracking and anti-seepage protective layer 3 pre-laid on the bottom plate is located above the bottom plate waterproof layer 2 and below the bottom plate structural layer 4. The ECC anti-cracking and anti-seepage protective layer 3 pre-laid on the plate avoids damage to the bottom plate waterproof layer 2 during the construction of the steel bar project in the bottom plate structural layer 4.

[0027] The pre-applied ECC anti-crack and anti-seepage protective layer 3 on the floor slab boasts mechanical properties such as ultra-high ductility, saturated cracking, minimal crack width, and strong anti-seepage capabilities. It also requires no vibration and is self-compacting. Upon completion, the strength does not need to reach 100%, but only needs to meet certain strength requirements, such as 1.2 MPa, before subsequent floor structure construction can proceed. This allows the ECC material's late-stage hydration to strengthen the interfacial bond with the floor slab structural layer 4. Upon completion and commissioning of the station structure, the pre-applied ECC anti-crack and anti-seepage protective layer 3 and the floor slab structural layer 4 will meet strength standards, forming a reliably connected laminate.

[0028] The floor slab thickness and reinforcement of traditional underground stations still need to be further increased and improved while meeting the stress requirements to meet the maximum crack width of 200um required by the specification. However, the pre-laid ECC anti-crack and anti-seepage protective layer 3 on the floor slab of the present invention forms countless saturated cracks under the same external force, and the width of each crack can be controlled to be below 50~100um. Compared with the crack width of 200um, the tiny crack width of 50~100um below will greatly improve the material's impermeability and corrosion resistance, thereby optimizing the floor slab thickness and reinforcement of traditional underground stations.

[0029] Combine Figure 1 The bottom plate structure layer 4 adopts the cast-in-place construction technology and is poured to the construction joints 6 on both sides of the bottom plate.

[0030] Combine Figure 8 The prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate is prefabricated in the factory. The bottom surface of the plate is provided with concave and convex grooves arranged in a crisscross pattern. A steel mesh is provided inside the plate. There are protruding steel bars around the plate and protruding U-shaped steel bars on the bottom surface of the plate. The above structures are all used to strengthen the integrity of the connection between the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate and the bottom plate structural layer 4.

[0031] The precast ECC anti-crack protection plate 5 on the top of the floor slab also boasts ultra-high ductility, saturated cracking, minimal crack width, and strong corrosion resistance. After the reinforcement skeleton of the floor slab structure layer 4 is tied, the precast ECC anti-crack protection plate 5 on the top of the floor slab is placed on top of the reinforcement skeleton of the floor slab structure layer 4. Concrete for the floor slab structure layer 4 is then poured. Once the concrete strength of the floor slab structure layer 4 reaches the required level, the precast ECC anti-crack protection plate 5 on the top of the floor slab is embedded into the surface layer of the floor slab structure layer 4, forming a single unit that shares the load.

[0032] In terms of layout position, the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate is arranged in the upper mid-span range of each span of the bottom plate structural layer 4. This range is where the bending moment is relatively large. Under the action of the same external force, the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate will form countless saturated cracks. The width of each crack can be controlled below 50~100um. Compared with the crack width of 200um, the tiny crack width below 50~100um will greatly improve the corrosion resistance of the material, thereby optimizing the bottom plate thickness and reinforcement of traditional underground stations.

[0033] In the floor area, after the above-mentioned pre-laid ECC anti-cracking and anti-seepage protective layer 3 on the floor and the prefabricated ECC anti-cracking protective plate 5 on the top of the floor, under the same external force, the thickness of the floor structure layer 4 in the present invention can be significantly smaller than the floor thickness of a traditional underground station, thereby saving the engineering cost of the station structure floor.

[0034] Specifically, such as Figure 3 、 Figure 4 As shown, within the second underground level, the order of component installation from the exterior to the interior of the station is: foundation pit retaining structure 7, leveling layer 8, second underground level waterproofing membrane 9, pre-paved ECC anti-cracking and anti-seepage protective layer 11 on the second underground level side walls, and second underground level side wall structure 12. Fixing nails 10 are used to secure the second underground level waterproofing membrane 9 to the foundation pit retaining structure 7 and leveling layer 8. The number of fixing nails 10 can be determined based on demand.

[0035] After the isolation membrane of the underground second floor waterproof membrane 9 is torn off, the ECC anti-cracking and anti-seepage protective layer 11 pre-laid on the underground second floor side wall is constructed on the underground second floor waterproof membrane 9 by using a spraying process or a coating process. Since the ECC anti-cracking and anti-seepage protective layer 11 pre-laid on the underground second floor side wall is located inside the underground second floor waterproof membrane 9 and outside the underground second floor side wall structure 12, it can protect the underground second floor waterproof membrane 9 from damage during the construction of the steel bar project in the underground second floor side wall structure 12, thereby eliminating the temporary baffles used in the traditional underground station side wall construction.

[0036] At the same time, the pre-applied ECC anti-crack and anti-seepage protective layer 11 on the underground second floor side wall exhibits mechanical properties such as ultra-high ductility, saturated cracking, small crack width, and strong anti-seepage capabilities. It is also sprayable or smearable for construction. After construction is complete, the strength does not need to reach 100%, but only needs to meet certain strength requirements, such as 1.2 MPa, before subsequent side wall construction can proceed. This allows the ECC material's later hydration to strengthen the interfacial bonding with the underground second floor side wall structure 12. Once the station structure is completed and commissioned, the pre-applied ECC anti-crack and anti-seepage protective layer 11 on the underground second floor side wall and the underground second floor side wall structure 12 will meet the strength requirements, forming a reliably connected superimposed layer.

[0037] The thickness and reinforcement of the side walls of traditional underground stations still need to be further increased and improved under the premise of meeting the stress requirements to meet the maximum crack width of 200um required by the specifications. The pre-paved ECC anti-cracking and anti-seepage protective layer 11 on the underground second-floor side wall of the present invention forms countless saturated cracks under the same external force, and the width of each crack can be controlled below 50~100um. Compared with the crack width of 200um, the tiny crack width of less than 50~100um will greatly improve the material's impermeability and corrosion resistance, thereby optimizing the side wall thickness and reinforcement of traditional underground stations. That is, under the same external force, the thickness of the underground second-floor side wall structure 12 of the present invention can be significantly smaller than the side wall thickness of traditional underground stations, thereby saving the engineering cost of the station structure side wall.

[0038] Combine Figure 1 The underground second floor side wall structure 12 adopts a cast-in-place construction process and is poured to the construction joint 16 at the top of the underground second floor side wall.

[0039] At the same time, the underground second-floor structural columns 14 and the middle plate structure 15 are both constructed using a cast-in-place construction process, and the concrete of the middle plate structure 15 is poured to the construction joints 16 on both sides of the middle plate.

[0040] Specifically, such as Figure 5 、 Figure 6 As shown, within the underground level, the order of component placement from the exterior to the interior of the station is: foundation pit retaining structure 7, leveling layer 8, underground level waterproofing membrane 17, pre-laid ECC anti-cracking and anti-seepage protective layer 18 on the underground level side walls, and underground level side wall structure 19. Fixing nails 10 are used to secure underground level waterproofing membrane 17 to the foundation pit retaining structure 7 and leveling layer 8. The number of fixing nails 10 can be determined based on demand.

[0041] After the isolation membrane of the underground first layer waterproof membrane 17 is torn off, the ECC anti-cracking and anti-seepage protective layer 18 pre-laid on the underground first layer side wall is constructed on the underground first layer waterproof membrane 17 by a spraying process or a coating process. Since the ECC anti-cracking and anti-seepage protective layer 18 pre-laid on the underground first layer side wall is located inside the underground first layer waterproof membrane 17 and outside the underground first layer side wall structure 19, it can protect the underground first layer waterproof membrane 17 from damage during the construction of the steel bar project in the underground first layer side wall structure 19, thereby eliminating the temporary baffles used in the traditional underground station side wall construction.

[0042] At the same time, the pre-applied ECC anti-crack and anti-seepage protective layer 18 on the underground side walls exhibits mechanical properties such as ultra-high ductility, saturated cracking, minimal crack width, and strong anti-seepage capabilities. It can also be sprayed or applied for construction. After construction is complete, the strength does not need to reach 100%, but only needs to meet certain strength requirements, such as 1.2 MPa, before subsequent side wall construction can proceed. This allows the ECC material's late-stage hydration to strengthen the interfacial bond with the underground side wall structure 19. Upon completion and commissioning of the station structure, the pre-applied ECC anti-crack and anti-seepage protective layer 18 on the underground side walls and the underground side wall structure 19 will meet strength standards, forming a reliably connected superimposed layer.

[0043] The thickness and reinforcement of the side walls of traditional underground stations still need to be further increased and improved under the premise of meeting the stress requirements to meet the maximum crack width of 200um required by the specification. In the present invention, the ECC anti-cracking and anti-seepage protective layer 18 pre-paved on the side walls of the first underground floor forms countless saturated cracks under the same external force, and the width of each crack can be controlled below 50~100um. Compared with the crack width of 200um, the tiny crack width of less than 50~100um will greatly improve the material's impermeability and corrosion resistance, thereby optimizing the side wall thickness and reinforcement of traditional underground stations. That is, under the same external force, the thickness of the first underground floor side wall structure 19 of this patent can be significantly smaller than the side wall thickness of traditional underground stations, thereby saving the engineering cost of the station structure side wall.

[0044] Combine Figure 1 The underground first floor side wall structure 19 adopts a cast-in-place construction process and is poured to the construction joint 20 at the top of the underground first floor side wall.

[0045] At the same time, the underground first floor structural columns 21 and the top plate structural layer 23 are both constructed using cast-in-place technology.

[0046] Specifically, such as Figure 7 As shown, in the top plate range, the order of component setting from bottom to top is: prefabricated ECC anti-cracking protection plate 22 at the bottom of the top plate, top plate structural layer 23, self-compacting ECC anti-cracking and anti-seepage protection layer 24 at the top plate, top plate waterproof layer 25, top plate waterproof isolation layer 26, and top plate fine stone concrete protection layer 27.

[0047] Combine Figure 8 The prefabricated ECC anti-crack protection plate 22 at the bottom of the top plate is prefabricated in the factory. The top surface of the plate is provided with concave and convex grooves arranged in a crisscross pattern. A steel mesh is provided inside the plate. There are protruding steel bars around the plate and protruding U-shaped steel bars on the top surface of the plate, all of which are used to strengthen the integrity of the connection between the prefabricated ECC anti-crack protection plate 22 at the bottom of the top plate and the top plate structural layer 23.

[0048] The precast ECC anti-crack protection plate 22 at the bottom of the roof slab also boasts mechanical properties such as ultra-high ductility, saturated cracking, minimal crack width, and strong corrosion resistance. After the formwork for the roof slab structure layer 23 is erected and before the reinforcement is attached, the precast ECC anti-crack protection plate 22 is laid on top of the formwork for the roof slab structure layer 23. Construction of the reinforcement and cast-in-place concrete for the roof slab structure layer 23 then proceeds. Once the concrete strength of the roof slab structure layer 23 reaches the required level, the precast ECC anti-crack protection plate 22 is embedded into the bottom layer of the roof slab structure layer 23, forming a single unit that shares the load.

[0049] The prefabricated ECC anti-crack protection plate 22 at the bottom of the roof is arranged in the lower mid-span range of each span of the roof structural layer 23. This range is where the bending moment is relatively large. Under the same external force, the prefabricated ECC anti-crack protection plate 22 at the bottom of the roof will form countless saturated cracks. The width of each crack can be controlled below 50~100um. Compared with the crack width of 200um, the tiny crack width of 50~100um will greatly improve the corrosion resistance of the material, thereby optimizing the roof thickness and reinforcement of traditional underground stations.

[0050] The self-compacting ECC anti-crack and anti-seepage protective layer 24 on the roof slab also boasts ultra-high ductility, saturated cracking, minimal crack width, and strong anti-seepage capabilities. It also requires no vibration and is self-compacting for construction. Upon completion and commissioning of the station structure, the self-compacting ECC anti-crack and anti-seepage protective layer 24 on the roof slab will form a securely connected laminate with the roof slab structural layer 23.

[0051] The roof thickness and reinforcement amount of traditional underground stations still need to be further increased and improved under the premise of meeting the stress requirements to meet the maximum crack width of 200um required by the specification. However, the self-compacting ECC anti-cracking and anti-seepage protective layer 24 at the roof of the present invention forms countless saturated cracks under the same external force, and the width of each crack can be controlled below 50~100um. Compared with the crack width of 200um, the tiny crack width of 50~100um below will greatly improve the material's impermeability and corrosion resistance, thereby optimizing the roof thickness and reinforcement of traditional underground stations. That is, under the same external force, the thickness of the roof structure layer 23 of the present invention can be significantly smaller than the roof thickness of traditional underground stations, thereby saving the engineering cost of the station structure roof.

[0052] A construction method for an underground station with a pre-laid ECC anti-cracking and anti-seepage protective structure comprises the following steps: A. In the base plate area, pre-lay the ECC anti-crack and anti-seepage protective layer 3 on the base plate, install the prefabricated ECC anti-crack protective plate 5 on the top of the base plate, and construct the base plate structural layer 4; B. In the area of ​​the second underground floor, pre-lay the ECC anti-cracking and anti-seepage protective layer 11 on the side walls of the second underground floor, and construct the side wall structure 12 of the second underground floor; C. Construction of mid-slab structure 15; D. In the underground first floor area, pre-lay the ECC anti-cracking and anti-seepage protective layer 18 on the underground first floor side wall, and construct the underground first floor side wall structure 19; E. In the roof area, install the prefabricated ECC anti-crack protection plate 22 at the bottom of the roof, construct the roof structural layer 23, and construct the self-compacting ECC anti-crack and anti-seepage protection layer 24 at the roof.

[0053] Specifically, in step A, in the base plate area, the ECC anti-crack and anti-seepage protective layer 3 is pre-laid on the base plate, the prefabricated ECC anti-crack protective plate 5 is installed on the top of the base plate, and the base plate structural layer 4 is constructed. The specific process is as follows: a1. Use cast-in-place technology to construct the base plate plain concrete cushion layer 1; a2. After its strength meets the requirements, lay the bottom waterproof layer 2 on it; a3. Pre-laying the ECC anti-crack and anti-seepage protective layer 3 on the base slab. Because the pre-laid ECC anti-crack and anti-seepage protective layer 3 on the base slab is self-compacting, it can achieve a dense and flat surface without vibration. There is no need to wait for the pre-laid ECC anti-crack and anti-seepage protective layer 3 on the base slab to reach 100% strength. As long as the strength meets certain requirements, such as reaching 1.2 MPa, the subsequent base slab structural layer 4 can be constructed using a cast-in-place construction process. a4. When the bottom plate structure layer 4 steel skeleton is tied, the prefabricated ECC anti-crack protection plate 5 is laid on top of the bottom plate; a5. Concrete pouring of the bottom plate structure layer 4 is carried out and poured to the construction joints 6 on both sides of the bottom plate; a6. When the concrete strength of the bottom plate structure layer 4 reaches the standard, the prefabricated ECC anti-crack protection plate 5 on the top of the bottom plate is embedded in the surface of the bottom plate structure layer 4, and the two form a whole to bear the force together.

[0054] Specifically, in step B, in the area of ​​the second underground floor, the ECC anti-cracking and anti-seepage protective layer 11 is pre-laid on the side wall of the second underground floor, and the side wall structure 12 of the second underground floor is constructed. The specific process is as follows: b1. After the floor structure layer 4 meets the strength requirements, the use of fixed nails 10 will be the underground second layer of waterproof membrane 9 reliably fixed to the foundation pit retaining structure 7, the leveling layer 8 above, the number of fixed nails 10 can be determined according to demand; b2 tear off the isolation membrane 9 of the underground second floor waterproof membrane, the use of spraying process or coating process will be pre-paved ECC crack-resistant anti-seepage protective layer 11 construction on the underground second floor waterproof membrane 9; b3. No need to wait for the underground second-floor side wall pre-paved ECC anti-crack and anti-seepage protective layer 11 to reach 100% strength, as long as the strength meets certain requirements, such as reaching 1.2MPa, you can proceed with the subsequent construction of the underground second-floor side wall structure 12; b4 Since the underground second-floor side wall pre-paved ECC anti-crack and anti-seepage protective layer 11 is set, the traditional underground station side wall construction used in temporary baffles; b5. Construction of the underground second floor side wall structure 12 and the underground second floor structural column 14. Both are constructed using cast-in-place technology. The concrete of the underground second floor side wall structure 12 is poured to the construction joint 13 at the top of the side wall within the underground second floor range.

[0055] Specifically, in step C, the middle plate structure 15 is constructed, and the specific process is as follows: The middle plate structure 15 is constructed by using a cast-in-place process, and the concrete of the middle plate structure 15 is poured to the construction joints 16 on both sides of the middle plate.

[0056] Specifically, in step D, in the underground first floor, the ECC anti-cracking and anti-seepage protective layer 18 is pre-laid on the underground first floor side wall, and the underground first floor side wall structure 19 is constructed. The specific process is as follows: d1. The construction steps of the side walls of the underground layer are the same as those of the underground second floor. After the strength of the plate structure 15 meets the requirements, the underground layer waterproof membrane 17 is reliably fixed to the foundation pit retaining structure 7 and the leveling layer 8 by fixing nails 10. The number of fixing nails 10 can be determined according to demand; d2. After tearing off the isolation membrane of the underground layer of waterproof membrane 17, the underground layer side wall pre-paved ECC anti-crack and anti-seepage protective layer 18 is constructed on the underground layer of waterproof membrane 17; d3. There is no need to wait for the underground side wall pre-paved ECC anti-crack and anti-seepage protective layer 18 to reach 100% strength. As long as the strength meets certain requirements, such as reaching 1.2MPa, the subsequent underground side wall structure 19 can be constructed; d4. Due to the pre-laid ECC crack-resistant and anti-seepage protective layer 18 on the underground side wall, the temporary baffle used in the traditional underground station side wall construction is cancelled; d5. Construct the underground first floor side wall structure 19 and underground first floor structural columns 21. Both are constructed using cast-in-place technology. The concrete of the underground first floor side wall structure 19 is poured to the construction joint 20 at the top of the underground first floor side wall.

[0057] Specifically, in step E, a prefabricated ECC anti-crack protection plate 22 is installed at the bottom of the roof, a roof structural layer 23 is constructed, and a self-compacting ECC anti-crack and anti-seepage protection layer 24 is constructed at the roof. The specific process is as follows: e1. Install the prefabricated ECC anti-crack protection plate 22 at the bottom of the top plate, and use cast-in-place construction technology to construct the top plate structure layer 23; e2 until the top plate structural layer 23 meets the strength requirements, the construction of the top plate at the self-compacting ECC anti-crack and anti-seepage protective layer 24, due to the self-compacting ECC anti-crack and anti-seepage protective layer 24 at the top plate has self-compacting properties, no vibration can achieve a dense, flat effect; e3. Once the self-compacting ECC anti-cracking and anti-seepage protective layer 24 on the roof meets the required strength, proceed with the construction of the roof waterproof layer 25, roof waterproof isolation layer 26, and roof fine stone concrete protective layer 27, completing the construction of the main structure of the open-cut urban rail underground station.

[0058] The present invention pre-lays an ECC protective layer on key locations such as the bottom plate, side walls and top plate. The crack width can be controlled at 50-100um, which is much lower than the traditional 200um. This greatly improves the impermeability and corrosion resistance, prevents groundwater infiltration, and ensures the safety of station operations.

[0059] Under the premise of meeting the stress requirements, the present invention optimizes the thickness and reinforcement amount of the bottom plate, side wall and top plate, thereby significantly reducing the project cost.

[0060] The invention is easy and efficient to construct, has the characteristics of self-compacting, no need for vibration or spraying, and can be applied. After reaching a certain strength after construction, subsequent construction can be carried out, shortening the construction period, and eliminating temporary side wall baffles, reducing construction difficulty and cost.

[0061] The present invention significantly improves the anti-cracking and anti-seepage performance of urban rail underground stations under the open-cut method, optimizes structural design, reduces engineering costs, improves construction efficiency, and has significant economic and social benefits.

Claims

1. A pre-laid ECC anti-crack and anti-seepage protection structure, characterized by: Its structure includes: A bottom plate structural layer (4), a bottom plate pre-laid ECC anti-crack and anti-seepage protective layer (3) is provided on the outer side of the bottom plate structural layer (4), and a bottom plate top prefabricated ECC anti-crack protective plate (5) is provided in the bottom plate structural layer (4); The underground second floor side wall structure (12) is provided with an underground second floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer (11) outside the underground second floor side wall structure (12); An underground first floor side wall structure (19), an underground first floor side wall pre-paved ECC anti-cracking and anti-seepage protective layer (18) is provided on the outer side of the underground first floor side wall structure (19); A top plate structural layer (23) is provided, a top plate self-compacting ECC anti-crack and anti-seepage protective layer (24) is provided on the outside of the top plate structural layer (23), and a top plate bottom prefabricated ECC anti-crack protective plate (22) is provided in the top plate structural layer (23).

2. The pre-laid ECC anti-crack and anti-seepage protection structure according to claim 1, characterized in that: The prefabricated ECC anti-crack protection plate (5) on the top of the bottom plate is prefabricated in a factory, the prefabricated ECC anti-crack protection plate (5) on the top of the bottom plate is provided with concave and convex grooves arranged in a crisscross pattern, a steel mesh is provided inside the prefabricated ECC anti-crack protection plate (5), and protruding steel bars are provided around the prefabricated ECC anti-crack protection plate (5).

3. The pre-laid ECC anti-cracking and anti-seepage protection structure according to claim 2, characterized in that: The end surface of the prefabricated ECC anti-crack protection plate (5) on the top of the bottom plate is provided with a U-shaped steel bar.

4. The pre-laid ECC anti-crack and anti-seepage protection structure according to claim 1, characterized in that: In the base plate range, the order of component arrangement from bottom to top is: base plate plain concrete cushion layer (1), base plate waterproof layer (2), base plate pre-laid ECC anti-cracking and anti-seepage protective layer (3), base plate structural layer (4), and base plate top prefabricated ECC anti-cracking protective plate (5).

5. The pre-laid ECC anti-cracking and anti-seepage protection structure according to claim 1, characterized in that: In the area of ​​the second underground floor, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure (7), leveling layer (8), second underground floor waterproof membrane (9), pre-laid ECC anti-cracking and anti-seepage protective layer on the side wall of the second underground floor (11), and second underground floor side wall structure (12).

6. The pre-laid ECC anti-crack and anti-seepage protection structure according to claim 1, characterized in that: In the underground level, the order of component installation from the outside to the inside of the station is: foundation pit retaining structure (7), leveling layer (8), underground level waterproof membrane (17), pre-laid ECC anti-cracking and anti-seepage protective layer on the underground level side wall (18), and underground level side wall structure (19).

7. The pre-laid ECC anti-cracking and anti-seepage protection structure according to claim 1, characterized in that: In the top plate range, the order of component installation from bottom to top is: prefabricated ECC anti-crack protection plate (22) at the bottom of the top plate, top plate structural layer (23), self-compacting ECC anti-crack and anti-seepage protection layer (24) at the top plate, top plate waterproof layer (25), top plate waterproof isolation layer (26), top plate fine stone concrete protection layer (27).

8. The pre-laid ECC anti-cracking and anti-seepage protection structure according to claim 5, characterized in that: The ECC anti-cracking and anti-seepage protective layer (11) pre-paved on the side wall of the second underground floor is constructed on the waterproof membrane (9) of the second underground floor by using a spraying process or a smearing process.

9. The method for constructing an underground station with a pre-laid ECC anti-cracking and anti-seepage protective structure according to claim 1, characterized in that: The following steps are involved: A. In the base plate area, pre-lay the ECC anti-crack and anti-seepage protective layer (3) on the base plate, install the prefabricated ECC anti-crack protective plate (5) on the top of the base plate, and construct the base plate structural layer (4); B. In the area of ​​the second underground floor, pre-lay the ECC anti-cracking and anti-seepage protective layer (11) on the side wall of the second underground floor, and construct the side wall structure (12) of the second underground floor; C. Construction of plate structure (15); D. In the underground first floor area, pre-lay the ECC anti-cracking and anti-seepage protective layer (18) on the underground first floor side wall and construct the underground first floor side wall structure (19); E. In the roof area, install the prefabricated ECC anti-crack protection plate (22) at the bottom of the roof, construct the roof structural layer (23), and construct the self-compacting ECC anti-crack and anti-seepage protection layer (24) at the roof.

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