Construction method for communicating subway accessory structure and main body structure

Abstract

The invention relates to the field of subway foundation construction, in particular to a construction method for communicating a subway accessory structure with a main body structure, which comprises the following steps: constructing an accessory structure continuous wall, and constructing a first support and a second support; earth is excavated to the bottom of the foundation pit, an air pick is adopted to break the diaphragm wall at the connecting position of the accessory structure and the main body structure after presplitting is conducted through a splitting rod, a bottom plate of the accessory structure is constructed, and a bottom plate within the range of the rear chiseling diaphragm wall is reserved for later pouring; the second support and the first support are dismantled in a segmented mode; and after breaking, the underground diaphragm wall is chiseled to the bottom of the accessory structure bottom plate, and an accessory structure post-cast strip is constructed. After the splitting rod is adopted for presplitting, the air pick is adopted for breaking the diaphragm wall at the connecting position of the accessory structure and the main body structure, and the influence of breaking construction on the main body structure can be reduced. And after the accessory structure top plate is constructed, the reserved supporting columns are broken, and the accessory structure post-cast strip is constructed, so that the underground diaphragm wall can be prevented from collapsing in the construction process, the construction risk caused to the main body structure during accessory structure construction is further reduced, and the construction safety is improved.

Description

Technical Field

[0001] The present invention relates to the field of subway foundation construction, and in particular to a construction method connecting a subway auxiliary structure and a main structure. Background Art

[0002] With the rapid development of urban rail transit, the scale of subway station construction continues to expand, and the connection between the main station structure and its ancillary structures has become a critical aspect of engineering construction. Subway station ancillary structures typically include entrances and exits, wind shelters, cooling towers, etc., and the connection between these structures and the main structure directly affects the project quality and operational functionality.

[0003] Currently, the main construction methods for connecting the main structure and ancillary structures of subway stations include open-cut and covered-cut methods. In the "Construction Method for Post-cast Joints Connecting the Main Body and Ancillary Structures of a Subway Station," disclosed in CN116950129B, a phased construction method for post-cast joints is adopted. The first post-cast joint is constructed simultaneously with the ancillary structure. After reaching the designed strength, the remaining ground-connecting walls are removed and the remaining post-cast joints are constructed. CN114960751B discloses "A Method for First Open-cut Construction of the Ancillary Structures at a Subway Station, Then Cover-cut and Reverse Construction of the Main Body." This method first constructs the ancillary retaining structures and the main ground-connecting walls at the junction with the main body. Then, the open-cut method is used to construct the ancillary foundation pit and the ancillary support frame. Finally, the covered-cut and reverse construction method is used to construct the main foundation pit and the main support frame.

[0004] Regarding the simultaneous construction of subway station main bodies and ancillary structures, CN114575384A discloses a "Construction Method for the Synchronous Construction of Underground Station Main Bodies and Ancillary Structures." This method involves simultaneous excavation of the foundation pits for both the main and auxiliary structures, avoiding the need for secondary excavation or support of parts of the main structure's foundation pit due to the construction of the auxiliary structures. CN104099944B, on the other hand, proposes a "Construction Method for the Interface between a Subway Station and a Large-Span Ancillary Structure." This method involves installing retaining piles and crown beams for the auxiliary structures, gradually removing the retaining piles for the main structure, and connecting the structure to the main structure via post-cast bottom slab strips.

[0005] However, the existing technology still has some problems in the process of demolishing the ground-connected wall at the connection between the subway auxiliary structure and the main structure. First, the demolition of the ground-connected wall usually adopts the method of demolishing the whole or large sections, which easily leads to the instability of the surrounding structure and increases the risk of construction safety. Secondly, the traditional demolition method often requires the installation of a large number of temporary supports, which not only increases the project cost, but also affects the construction efficiency. Third, in the process of demolishing the ground-connected wall, how to ensure structural stability and construction safety is a technical difficulty. Although the "support method for post-removal of the station connection without dismantling the work condition" proposed in CN117468504A ensures overall stability by adding a supporting structure, its supporting structure design is relatively complex and the construction is difficult.

[0006] Furthermore, existing techniques for dismantling ground-connected walls lack systematic guidance, particularly regarding the selection of tools, the order in which they are dismantled, and the placement of temporary supports. This can lead to safety hazards during construction. Furthermore, methods for handling structural connections after dismantling are also inadequate, impacting the structural integrity and waterproofing performance.

[0007] Therefore, how to ensure construction safety and structural stability during the demolition of the ground-connected wall where the attachment is connected to the main body is a technical problem that needs to be solved urgently in the construction of subway stations. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a construction method for connecting the subway auxiliary structure and the main structure, which can minimize the disturbance to the subway main structure while ensuring the effective demolition of the ground-connected wall, thereby ensuring the construction quality and safety of the entire project.

[0009] A construction method for connecting a subway auxiliary structure and a main structure, comprising the following steps: S1: Construct the auxiliary structure continuous wall, excavate the surface soil to the bottom elevation of the crown beam, and then break the head of the auxiliary structure continuous wall; S2: Excavate the foundation pit to below the first support elevation, construct the auxiliary structure wall top beam and retaining wall, and construct the first support; S3: Excavate the foundation pit to below the second support elevation and construct the second support; S4: Excavate to the bottom of the foundation pit, remove the ground connection wall where the auxiliary structure meets the main structure, construct the base plate of the auxiliary structure, and leave space within the range of the ground connection wall for post-casting of the base plate; Among them, the method of breaking the ground connection wall where the auxiliary structure and the main structure meet is: The ground-connected wall is broken down in layers and sections, with a support column reserved at every longitudinal interval of 8m-14m. The reserved support columns are broken down after the construction of the auxiliary structure top plate is completed. The ground-connected wall is pre-cracked with a splitting rod and then broken down with a jackhammer. First, a water drill is used to drill a hole, and a hydraulic pre-crack rod is inserted into the drilled hole to crack the hole. After cracking, a jackhammer is used to break the wall. S5: After the strength of the auxiliary structure bottom plate reaches 80% of the design strength, the second support is removed in sections, the unsupported ground-connected wall within the top plate range is chiseled out, and the side walls and top plate of the auxiliary structure are constructed, leaving space for the top plate within the range of the chiseled ground-connected wall for post-casting; S6: After the top slab of the auxiliary structure is poured in sections, the top slab is backfilled in layers and sections, and the first support is removed in sections; S7: After demolition, chisel the ground connecting wall to the bottom of the auxiliary structure base plate and construct the auxiliary structure post-cast joint.

[0010] Preferably, the first support is a concrete support, which is cast on site.

[0011] Preferably, the second support is made of steel and prestressed. Preferably, the axial force of the second support is monitored during the construction process.

[0012] Preferably, the cross-sectional area of ​​the support column is 1m 2 -2m 2 .

[0013] Preferably, the water drilling holes are spaced 0.4m-0.8m apart in the horizontal and vertical directions respectively.

[0014] Preferably, in step S1, a dewatering well is constructed.

[0015] Preferably, in step S1, the dewatering well is drilled using a rotary drilling rig.

[0016] Preferably, in step S4, a bottom plate waterproof layer is constructed, and in step S5, a side wall waterproof layer and a top plate waterproof layer are constructed.

[0017] Preferably, the top settlement, top horizontal displacement and wall deformation of the auxiliary structure continuous wall and ground-connected wall are monitored during the construction process.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a construction method for connecting a subway auxiliary structure and a main structure. The method is applicable to the construction process of a subway auxiliary structure and a main structure sharing a ground connection wall. First, the first support and the second support are used to achieve stable support for the subway auxiliary structure. On this basis, a splitting rod is used for pre-cracking, and then a jackhammer is used to break the ground connection wall at the connection point between the auxiliary structure and the main structure. This method can minimize the impact of the breaking construction on the main structure, achieve a safe connection between the auxiliary structure and the main structure, reduce the construction risk to the main structure during the construction of the auxiliary structure, improve the safety of the construction, and at the same time reduce vibration and noise, reducing the impact on the surrounding environment. Furthermore, the ground connection wall is broken in sections along the longitudinal direction, and a support column is reserved every 8m-14m. After the construction of the auxiliary structure top plate is completed, the reserved support column is broken. After the breaking, the ground connection wall is chiseled to the bottom of the auxiliary structure bottom plate, and the auxiliary structure post-casting strip is constructed. This can prevent the upper ground connection wall from falling during construction, further improve construction safety, and reduce the construction risk to the main structure during the construction of the auxiliary structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of step S1 in the construction method of the present invention.

[0020] Figure 2Schematic diagram of the structure of step S2 in the construction method of the present invention.

[0021] Figure 3 Schematic diagram of the structure of step S3 in the construction method of the present invention.

[0022] Figure 4 Schematic diagram of the structure of step S4 in the construction method of the present invention.

[0023] Figure 5 Schematic diagram of the structure of step S5 in the construction method of the present invention.

[0024] Figure 6 It is a structural schematic diagram of steps S6 and S7 in the construction method of the present invention.

[0025] Figure 7 This is a structural diagram of reserving support columns and constructing post-cast strips of auxiliary structures in the construction method described in the present invention.

[0026] Markings in the figure: 1-main structure, 2-continuous wall of auxiliary structure, 3-ground-connected wall, 4-first support, 5-second support, 6-broken area, 7-bottom plate of auxiliary structure, 8-side wall of auxiliary structure, 9-top plate of auxiliary structure, 10-support column, 11-post-cast strip of auxiliary structure. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0028] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating orientation or positional relationships such as "upper," "lower," "left," "right," "center," "inside," and "outside" are based on the orientation or positional relationships shown in the accompanying drawings, or are the orientation or positional relationships in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationships are merely for the purpose of facilitating the description of the present invention or simplifying the description of the specific embodiments to facilitate a quick understanding of the solutions by technicians, and do not indicate or imply that a particular device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0029] In addition, the use of terms such as "horizontal," "vertical," "overhanging," "parallel," and "coaxial" does not necessarily require that the corresponding devices / components / elements be absolutely horizontal, vertical, overhanging, parallel, or coaxial. Instead, they may be slightly tilted or have deviations, as long as they do not affect the normal function of the relevant components. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted. "Coaxial" means that the two components are arranged as coaxially as possible, so that they move in a coaxial or approximately coaxial manner when their relative positions change. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are arranged in a "horizontal," "vertical," "overhanging," "parallel," or "coaxial" direction, and can have an error / deviation of ±10% relative to the corresponding direction, more preferably within an error / deviation of ±8%, more preferably within an error / deviation of ±6%, more preferably within an error / deviation of ±5%, and more preferably within an error / deviation of ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0030] In addition, the expressions “first”, “second”, “third”, etc. in the terms are merely used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0031] In addition, in the description of the embodiments of the present invention, "several," "a plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0032] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0033] Example 1 A construction method for connecting a subway auxiliary structure and a main structure 1 comprises the following steps: S1: If Figure 1As shown, the auxiliary structure diaphragm wall 2 is constructed. The topsoil is excavated to the bottom elevation of the crown beam, and the head of the auxiliary structure diaphragm wall 2 is broken. During this step, a dewatering well is first constructed. This well is drilled using a rotary drilling rig to lower the groundwater level and ensure the safe excavation of the foundation pit and subsequent construction. Preferably, during this step, the quality of the ground-connected wall 3 is tested, and initial monitoring data for the ground-connected wall 3 is collected.

[0034] S2: If Figure 2 As shown, the foundation pit is excavated to below the elevation of the first support 4, and the auxiliary structure wall top beam and retaining wall are constructed, and the first support 4 is constructed. The first support 4 is made of concrete support and is formed by pouring on site. It has high rigidity and stability, can effectively support the side wall of the foundation pit, and prevent soil deformation.

[0035] S3: If Figure 3 As shown, the foundation pit is excavated to below the elevation of the second support 5, and then the second support 5 is constructed. The second support 5 is made of steel and prestressed to improve the support effect. During construction, the axial force of the second support 5 needs to be monitored to ensure that the support system is in a safe working condition and the prestressing force is adjusted in a timely manner to prevent support failure or excessive deformation.

[0036] S4: As Figure 4 As shown, excavation is carried out to the bottom of the foundation pit, the ground connection wall 3 where the auxiliary structure meets the main structure 1 is removed, and the base plate 7 of the auxiliary structure is constructed. The base plate within the scope of the ground connection wall 3 is left open for post-casting. Before the base plate is constructed, a waterproof layer is first constructed to ensure the waterproof performance of the structure.

[0037] The method for breaking the ground-connected wall 3 at the junction of the auxiliary structure and the main structure 1 is as follows: the ground-connected wall 3 is broken in sections along the longitudinal direction, and a support column 10 is reserved every 8m-14m. The cross-sectional area of ​​the support column 10 is 1m²-2m². After the construction of the auxiliary structure top plate 9 is completed, the reserved support column 10 is broken. Figure 7 The ground-connected wall 3 is pre-split with splitting rods and then broken with a jackhammer. First, a water drill is used to drill holes with horizontal and vertical intervals of 0.4m-0.8m. Hydraulic pre-splitting rods are inserted into the drilled holes to perform pre-splitting. After pre-splitting, the wall is broken with a jackhammer.

[0038] In a preferred embodiment, the method for breaking the connecting wall 3 at the connection position between the auxiliary structure and the main structure 1 is: (1) The ground connection wall 3 at the connection position between the auxiliary structure and the main structure 1 is demolished gradually and layer by layer after the foundation pit cushion layer is poured. After the cushion layer is poured, the height of the area above the bottom plate is demolished. After the bottom plate is poured, the steel support is removed and the area is demolished to 50 cm above the auxiliary top / middle plate surface, that is, the demolition area 6.

[0039] (2) The ground-connected wall 3 is broken down into longitudinal sections, and a 1m*1m column (the location of the ground-connected wall steel) is reserved every 12 meters to prevent the upper ground-connected wall from falling.

[0040] (3) The ground-connected wall 3 was pre-cracked with a splitting rod and then broken by a jackhammer. First, a water drill was used to drill holes with a horizontal and vertical spacing of 500*500mm. A hydraulic splitting rod was inserted into the prepared hole position to perform pre-cracks. After pre-cracks, the wall was manually broken by a jackhammer.

[0041] S5: If Figure 5 As shown, after the auxiliary structure's base slab 7 reaches 80% of its design strength, the second support 5 is removed in sections, the unsupported ground-connected wall 3 within the roof is chiseled out, and the auxiliary structure's side walls 8 and roof slab 9 are constructed. The roof slab within the chiseled ground-connected wall 3 is then cast later. Before constructing the side walls and roof, a waterproof layer is applied to the side walls and roof, forming a complete waterproof system.

[0042] S6: As Figure 6 As shown, after the auxiliary structure top plate 9 is cast in sections, the top plate is backfilled with soil in layers and sections, and the first support 4 is removed in sections.

[0043] S7: After demolition, drill the ground connecting wall 3 to the bottom of the auxiliary structure base plate 7, and construct the auxiliary structure post-cast joint 11.

[0044] Throughout the construction process, it is necessary to monitor the top settlement, top horizontal displacement, and wall deformation of the auxiliary structure's diaphragm wall 2 and ground-connected wall 3 to ensure construction safety and structural stability. Through analysis of monitoring data, the construction plan can be adjusted in a timely manner to control deformation within the allowable range.

[0045] This construction method, by rationalizing the construction sequence and employing the method of gradually removing the ground-connecting wall 3 and reserving support columns 10, effectively resolves the construction difficulties at the connection between the auxiliary structure and the main structure 1, ensuring structural safety and construction quality. Furthermore, the provision of a waterproof layer and post-cast joints ensures the waterproof performance and integrity of the subway auxiliary structure.

[0046] 1. By adopting a seven-step operation process, a safe connection between the auxiliary structure and the main structure is achieved, ensuring structural stability throughout the construction process; 2. By breaking down the ground-connected wall in sections along the longitudinal direction and reserving support columns every 8m-14m, the upper ground-connected wall is effectively prevented from falling, ensuring structural safety; 3. The combination of water drilling + hydraulic splitting rod pre-splitting + manual jackhammer breaking reduces vibration and noise, reduces the impact on the surrounding environment, and improves construction efficiency; 4. By removing the ground-connected wall in layers and sections, the overall stability of the structure is ensured during construction, avoiding potential safety hazards caused by large-scale removal. 5. By monitoring the supporting axial force and the deformation of the continuous wall, comprehensive monitoring of the construction process is achieved, potential problems are discovered and resolved in a timely manner, and construction safety is further improved.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A construction method for connecting a subway auxiliary structure and a main structure, characterized in that: The following steps are involved: S1: construct the auxiliary structure continuous wall (2), excavate the surface soil to the bottom elevation of the crown beam, and then break the top of the auxiliary structure continuous wall (2); S2: Excavate the foundation pit to below the elevation of the first support (4), construct the top beam and retaining wall of the auxiliary structure, and construct the first support (4); S3: Excavate the foundation pit to below the elevation of the second support (5) and construct the second support (5); S4: Excavate the earthwork to the bottom of the foundation pit, remove the ground connection wall (3) at the connection position between the auxiliary structure and the main structure (1), construct the auxiliary structure bottom plate (7), and leave room for the bottom plate to be poured after the ground connection wall is cut; The method for breaking the ground connection wall (3) at the connection position between the auxiliary structure and the main structure (1) is: The ground-connected wall (3) is broken down in layers and sections, with a support column (10) reserved at every longitudinal interval of 8m-14m. The reserved support column (10) is broken down after the construction of the auxiliary structure top plate (9) is completed. The ground-connected wall (3) is pre-cracked with a splitting rod and then broken down with a jackhammer. First, a water drill is used to drill a hole, and a hydraulic pre-crack rod is inserted into the drilled hole to perform cracking. After cracking, the wall is broken down with a jackhammer. S5: After the strength of the auxiliary structure bottom plate (7) reaches 80% of the design strength, the second support (5) is removed in sections, the unsupported ground-connected wall (3) within the top plate range is chiseled out, and the auxiliary structure side walls (8) and the auxiliary structure top plate (9) are constructed, leaving room for the top plate within the chiseled ground-connected wall range to be poured later; S6: After the top plate (9) of the auxiliary structure is poured in sections, the top plate is backfilled in layers and sections, and the first support (4) is removed in sections; S7: After demolition, the ground connecting wall (3) is chiseled to the bottom of the auxiliary structure base plate (7), and the auxiliary structure post-casting strip (11) is constructed.

2. A construction method for connecting a subway auxiliary structure and a main structure according to claim 1, characterized in that: The first support (4) is a concrete support, cast on site.

3. The construction method for connecting a subway auxiliary structure and a main structure according to claim 1, characterized in that: The second support (5) is made of steel and is prestressed.

4. A construction method for connecting a subway auxiliary structure and a main structure according to claim 3, characterized in that: During the construction process, the axial force of the second support (5) is monitored.

5. The construction method for connecting a subway auxiliary structure and a main structure according to claim 1, characterized in that: The cross-sectional area of ​​the support column (10) is 1m 2 -2m 2 .

6. The construction method for connecting a subway auxiliary structure and a main structure according to claim 1, characterized in that: The water drilling holes are spaced 0.4m to 0.8m apart in the horizontal and vertical directions.

7. The construction method for connecting a subway auxiliary structure and a main structure according to claim 1, characterized in that: In step S1, a dewatering well is constructed.

8. The construction method for connecting a subway auxiliary structure and a main structure according to claim 7, characterized in that: In step S1, a dewatering well is drilled using a rotary drilling rig.

9. The construction method for connecting a subway auxiliary structure and a main structure according to claim 7, characterized in that: In step S4, a bottom plate waterproof layer is constructed, and in step S5, a side wall waterproof layer and a top plate waterproof layer are constructed.

10. A construction method for connecting a subway auxiliary structure and a main structure according to any one of claims 1 to 9, characterized in that: During the construction process, the top settlement, top horizontal displacement and wall deformation of the auxiliary structure continuous wall (2) and the ground-connected wall (3) are monitored.

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