A construction method for a newly-built station adjacent to an existing station

Abstract

The present application relates to the civil engineering subway station construction technical field, specifically discloses a kind of new station construction method close to existing station, the bottom plate elevation of new station is lower than the bottom plate elevation of original subway station, comprising the following steps: S1, new station foundation pit is close to the side of existing station using existing retaining pile, other side is made new retaining pile, layered excavation soil and make first concrete support and lower steel support;S2, when excavating to new station middle plate position, the middle plate of new station is close to the side of existing station, and the profiled frame column of interval distribution is sequentially constructed below the middle plate of new station.The present application uses existing retaining pile to act as the side wall of new station platform layer, which reduces the demolition workload of existing retaining pile, reduces the disturbance to the height difference soil body below the original station, speeds up the construction progress, reduces the engineering cost, and improves the safety of construction.

Description

Technical Field

[0001] This invention relates to the field of civil engineering subway station construction technology, specifically to a construction method for a new station located adjacent to an existing station. Background Technology

[0002] In some cities with rapid population and economic development and ever-changing subway construction, there have even been cases where new subway stations are being built right next to the retaining piles of existing subway stations. Generally, when the elevation of the foundation slab of the new subway station is not lower than that of the foundation slab of the original subway station, the existing retaining piles on the side closest to the original station can be reused during the foundation pit construction of the new subway station. Subsequently, after the foundation slab, middle slab, and top slab of the new subway station are completed, the existing retaining piles on the side of the original station are removed, and then the side wall of the new station adjacent to the original subway station is finally constructed.

[0003] However, when the elevation of the base slab of the new station is lower than that of the original subway station, if the existing retaining piles on one side of the original station are removed using traditional construction methods, the soil pressure at the elevation difference between the new and old stations will have no structural support, causing excessive disturbance and impact on the existing station, which will inevitably lead to the original subway station being in a dangerous state. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a construction method for building a new station adjacent to an existing station.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a construction method for a new subway station adjacent to an existing station, wherein the elevation of the base slab of the new station is lower than that of the original subway station, comprising the following steps: S1. On the side of the new station foundation pit closest to the existing station, the existing retaining piles are used, and new retaining piles are constructed on the other sides. The soil is excavated in layers and the first layer of concrete support and the steel support below are constructed. S2. When the excavation reaches the position of the middle slab of the new station, irregularly shaped frame columns are constructed sequentially and at intervals below the middle slab on the side of the new station closer to the existing station. S3. When continuing to excavate the soil in layers and construct steel supports to the position of the existing station's bottom slab, grout the soil below the existing station at an angle in the foundation pit to form a grouting reinforcement area. S4. On the side closest to the existing station, except for the location of the irregular frame column, a skip excavation is carried out between adjacent existing retaining piles to form an irregular retaining wall; S5. Continue to excavate the soil in layers to the design elevation of the foundation pit of the new station, and construct the bottom slab and the side wall of the platform of the new station away from the existing station in sections. S6. Formwork, rebar tying, and concrete pouring are used to form the middle slab of the station; the side walls of the new station hall, which are far from the existing station, are constructed in sections, and formwork, rebar tying, and concrete pouring are used to form the roof slab of the station. S7. Cut and remove the existing retaining piles in the concourse level of the new station in sections, and construct a connecting beam at the base of the side wall of the concourse level of the new station near the existing station. The steel bars of the connecting beam, the existing retaining piles and the special frame column are effectively connected and tied. S8. Construct a station hall side wall on the side of the connecting beam that is close to the existing station exterior wall. The steel bars of the station hall side wall are effectively connected and tied to the steel bars of the connecting beam. The top of the station hall side wall is fixedly connected to the roof slab.

[0006] Furthermore, in S6, the newly built station slab near the existing station is supported on the irregular frame column.

[0007] Furthermore, in S2, the irregular frame column is located between two adjacent existing retaining piles on the side of the new station closer to the existing station, and there are three existing retaining piles between the two adjacent irregular frame columns.

[0008] Furthermore, the width of the irregular frame column is greater than the radius of the existing retaining pile and less than the diameter of the existing retaining pile.

[0009] Furthermore, in S3, the width of the grouting reinforcement area is not less than half the width of the existing station, and the bottom elevation of the grouting reinforcement area is not higher than the bottom elevation of the newly built station.

[0010] Furthermore, the width of the irregular retaining wall is equal to the radius of the existing retaining piles.

[0011] Furthermore, the top of the irregular retaining wall is at least 0.5m higher than the base plate of the existing station.

[0012] Furthermore, in S5, after excavation reaches the design elevation of the foundation pit for the new station, a drainage ditch is constructed below the base slab of the new station on the side closest to the existing station.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes existing retaining piles as the side walls of the new station platform, which reduces the amount of work required to demolish the existing retaining piles, minimizes disturbance to the soil beneath the original station, accelerates construction progress, reduces project costs, and improves construction safety. 2. This invention provides a load-bearing support point for the middle slab of the new station by constructing irregularly shaped frame columns at intervals under the middle slab on the side of the new station closest to the existing station, with the irregularly shaped frame columns located between adjacent existing retaining piles. This eliminates the need to construct new frame columns between the existing retaining piles, thereby expanding the usable space of the platform level. Furthermore, by setting up irregularly shaped retaining walls between the existing retaining piles, the irregularly shaped retaining walls can ensure the stability of the earth pressure support at the elevation difference without occupying additional space. 3. The present invention constructs a new reinforced concrete side wall on the side of the new station concourse level close to the existing station. This side wall is connected to the existing retaining piles, irregular frame columns and middle plate below through connecting beams. The method of using the existing retaining piles for the new station platform level has no impact on the new station concourse level, thus ensuring the normal use of the new station concourse level. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a cross-sectional view of a newly constructed station after excavation, according to an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram illustrating the construction process of irregularly shaped frame columns and irregularly shaped retaining walls according to an embodiment of the present invention.

[0016] Figure 3 This is a top view of an embodiment of the present invention, showing an irregularly shaped frame column, an irregularly shaped retaining wall, and existing retaining piles.

[0017] Figure 4 This is a schematic diagram of the structure of an irregular retaining wall according to an embodiment of the present invention.

[0018] Figure 5 This is a cross-sectional schematic diagram of an irregular retaining wall according to an embodiment of the present invention.

[0019] Figure 6 This is a schematic diagram of the structure of an irregularly shaped frame column according to an embodiment of the present invention.

[0020] Figure 7 This is a cross-sectional schematic diagram of an irregularly shaped frame column according to an embodiment of the present invention.

[0021] Figure 8 This is a schematic diagram of the structure of the central slab of a newly built station according to an embodiment of the present invention.

[0022] Figure 9 This is a schematic diagram of the structure of a newly built station slab supported by an irregularly shaped frame column according to an embodiment of the present invention.

[0023] Figure 10 This is a cross-sectional view of a newly built station according to an embodiment of the present invention.

[0024] Figure 11 This is a schematic diagram of the structure of a newly built station after completion, according to an embodiment of the present invention.

[0025] Figure 12 This is a structural schematic diagram from another perspective of the completed construction of a newly built station according to an embodiment of the present invention.

[0026] In the diagram: 1. Existing station; 2. Existing retaining piles; 3. Newly built retaining piles; 4. Concrete support; 5. Steel support; 6. Grouting reinforcement area; 7. Drainage ditch; 8. Irregular retaining wall; 9. Irregular frame column; 10. New station middle slab; 11. Bottom slab; 12. Connecting beam; 13. Side wall of the concourse level; 14. Top slab. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see Figure 1-12 The present invention discloses a construction method for a new subway station adjacent to an existing station, wherein the elevation of the new station's foundation slab is lower than that of the original subway station's foundation slab, comprising the following steps: S1. On the side of the new station foundation pit closest to the existing station 1, use the existing retaining piles 2, and on the other side, construct new retaining piles 3. Excavate the soil in layers and construct the first concrete support 4 and the steel support below 5. S2. When the excavation reaches the position of the middle slab 10 of the new station, irregular frame columns 9 are constructed sequentially and spaced apart on the side of the new station close to the existing station 1. The irregular frame columns 9 are located between two adjacent existing retaining piles 2. The irregular frame columns 9 are in close contact with the outer surface of the side wall of the existing station 1 and the outer surface of the two adjacent existing retaining piles 2. The width of the irregular frame columns 9 is greater than the radius of the existing retaining piles 2 and smaller than the diameter of the existing retaining piles 2. The existing retaining piles 2 are used as side walls on the side of the new station platform level close to the existing station 1. Therefore, during the construction of the new station middle slab 10, it is necessary to build a load-bearing support point near the existing retaining piles 2. In order to save space, multiple irregular frame columns 9 are constructed. There are three existing retaining piles 2 between two adjacent irregular frame columns 9, so that the outer contour of the irregular frame column 9 does not exceed the outer contour of the original retaining piles, and can provide a load-bearing support point for the new station middle slab 10. The irregular frame columns 9 bear part of the load of the new station middle slab 10. S3. When continuing to excavate the soil in layers and construct steel supports 5 to the position of the bottom plate 11 of the existing station 1, grout the soil below the existing station 1 at an angle in the foundation pit to form a grouting reinforcement area 6. The width of the grouting reinforcement area 6 shall not be less than half the width of the existing station 1, and the bottom elevation of the grouting reinforcement area 6 shall not be higher than the elevation of the bottom plate 11 of the new station. The function of grouting reinforcement area 6 is: on the one hand, to grout and reinforce the soil under the existing station 1 which is greatly affected by construction disturbance, thereby increasing the strength of the soil and providing effective protection for the existing station 1; on the other hand, the soil permeability coefficient is reduced after grouting and reinforcement, effectively preventing the possibility of groundwater in the soil under the existing station 1 seeping and flowing towards the new station foundation pit. S4. When the excavation of the new station foundation pit reaches an elevation lower than that of the adjacent original subway station, the soil gaps between the existing retaining piles 2 will form a vertical free surface. Its lateral earth pressure is unsupported by any structure, which will obviously pose a potential hazard and impact on the adjacent original subway station. Therefore, on the side close to the existing station 1, except for the location of the irregular frame column 9, a special retaining wall 8 is formed by skip excavation between the adjacent existing retaining piles 2. The special retaining wall 8 is used to support the gaps between the existing retaining piles 2. The special retaining wall 8 is in close contact with the outer surface of the side wall of the existing station 1 and the outer surface of the two adjacent existing retaining piles 2. The width of the special retaining wall 8 is equal to the radius of the existing retaining piles 2. The top of the special retaining wall 8 is not less than 0.5m higher than the bottom slab 11 of the existing station 1. S5. Continue to excavate the soil in layers to the design elevation of the foundation pit of the new station. Construct a drainage ditch 7 below the bottom slab 11 of the new station on the side closer to the existing station 1. Construct the bottom slab 11 and the side wall of the platform of the new station on the side away from the existing station 1 in sections. The drainage ditch 7 can quickly divert the accumulated water between the existing station 1 and the new station to the collection well (usually located at the corner of the bottom plate 11), reducing the water accumulation outside the platform walls of the existing station 1 and the new station from the source, effectively reducing or even eliminating water seepage problems. S6. Formwork, rebar binding, and concrete pouring are used to form the station's central slab. The newly built central slab 10 of the station, which is closer to the existing station 1, is supported on the irregular frame column 9. The side wall 13 of the new station hall, which is away from the existing station 1, is constructed in sections. Formwork, rebar binding, and concrete pouring are used to form the station's top slab 14. S7. Cut and remove the existing retaining piles 2 in the concourse level of the new station in sections, and construct a connecting beam 12 at the base of the side wall 13 of the concourse level of the new station near the existing station 1. Reserve a sufficient length of steel bars at the top of the irregular frame column 9. The connecting beam 12, the existing retaining piles 2 and the steel bars of the irregular frame column 9 form an effective connection and binding. S8. On the side of the connecting beam 12 that is close to the outer wall of the existing station 1, a concourse side wall 13 is constructed. The steel bars of the concourse side wall 13 are effectively connected and tied to the steel bars of the connecting beam 12. The top of the concourse side wall 13 is fixedly connected to the top plate 14.

[0029] Compared with the traditional approach of completely demolishing the existing retaining piles 2 and constructing a new side wall, this invention utilizes the existing retaining piles 2 as the side wall of the platform level. This reduces the amount of demolition work required for the existing retaining piles 2, minimizes disturbance to the soil at the elevation difference below the existing station 1, accelerates construction progress, reduces project costs, and improves construction safety. A new reinforced concrete side wall 13 is constructed on the side of the new station concourse level closest to the existing station 1. It is connected to the existing retaining piles 2, the irregular frame columns, and the new station central slab 10 below through connecting beams 12. The use of the existing retaining piles 2 for the platform level has no impact on the concourse level, ensuring the normal use of the concourse level. The construction steps described do not include detailed information on the construction of the new retaining piles 3, concrete supports 4, and steel supports 5; the fabrication of the irregular steel reinforcement cages for the irregular frame columns 9 and the irregular retaining walls 8; the excavation of irregular pits; the demolition and support replacement process during the excavation of the foundation pit; the details of steel reinforcement binding and connection during the construction of each structural segment; the details of waterproofing construction of the base slab 11 and the side walls; and various structural requirements, construction interval requirements, and strength requirements. All of these can be completed according to existing known technologies, relevant specifications, and industry standards, and will not be elaborated here.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A construction method for a new station adjacent to an existing station, characterized in that, The elevation of the base slab (11) of the newly built station is lower than that of the base slab (11) of the original subway station, including the following steps: S1. The existing retaining piles (2) are used on the side of the new station foundation pit closest to the existing station (1), and new retaining piles (3) are constructed on the other side. The soil is excavated in layers and the first concrete support (4) and the steel support below (5) are constructed. S2. When the excavation reaches the position of the middle slab (10) of the new station, irregularly shaped frame columns (9) are constructed in sequence on the side of the new station close to the existing station (1). S3. When continuing to excavate the soil layer by layer and construct steel support (5) to the position of the bottom plate (11) of the existing station (1), grout the soil below the existing station (1) at an angle in the foundation pit to form a grouting reinforcement area (6). S4. On the side close to the existing station (1), between adjacent existing retaining piles (2) except for the location of the irregular frame column (9), a irregular retaining wall (8) is formed by skip excavation. S5. Continue to excavate the soil layer by layer to the design elevation of the foundation pit of the new station, and construct the bottom slab (11) and the side wall of the platform of the new station away from the existing station (1) in sections. S6, formwork, steel reinforcement binding, and concrete pouring to form the station's middle slab; the new station hall side wall (13) on the side away from the existing station (1) is constructed in sections, and formwork, steel reinforcement binding, and concrete pouring are used to form the station's top slab (14). S7. Cut and remove the existing retaining piles (2) in the concourse of the new station in sections, and construct a connecting beam (12) at the root of the side wall (13) of the concourse of the new station near the existing station (1). The steel bars of the connecting beam (12), the existing retaining piles (2) and the special frame column (9) are effectively connected and tied. S8. On the side of the connecting beam (12) that is close to the outer wall of the existing station (1), a station hall side wall (13) is constructed. The steel bars of the station hall side wall (13) are effectively connected and tied with the steel bars of the connecting beam (12). The top of the station hall side wall (13) is fixedly connected to the top plate (14).

2. The construction method for a new station adjacent to an existing station according to claim 1, characterized in that, In S6, the newly built station slab (10) on the side closer to the existing station (1) is supported on the irregular frame column (9).

3. The construction method for a new station adjacent to an existing station according to claim 1, characterized in that, In S2, the irregular frame column (9) is located between two adjacent existing retaining piles (2) on the side of the new station close to the existing station (1), and there are three existing retaining piles (2) between the two adjacent irregular frame columns (9).

4. The construction method for a new station adjacent to an existing station according to claim 3, characterized in that, The width of the irregular frame column (9) is greater than the radius of the existing retaining pile (2) and less than the diameter of the existing retaining pile (2).

5. The construction method for a new station adjacent to an existing station according to claim 1, characterized in that, In S3, the width of the grouting reinforcement area (6) is not less than half the width of the existing station (1), and the bottom elevation of the grouting reinforcement area (6) is not higher than the elevation of the bottom plate (11) of the newly built station.

6. The construction method for a new station adjacent to an existing station according to claim 1, characterized in that, The width of the irregular retaining wall (8) is equal to the radius of the existing retaining piles (2).

7. The construction method for a new station adjacent to an existing station according to claim 6, characterized in that, The top of the irregular retaining wall (8) is at least 0.5m higher than the bottom plate (11) of the existing station (1).

8. The construction method for a new station adjacent to an existing station according to claim 1, characterized in that, In S5, after excavation reaches the design elevation of the foundation pit of the new station, a drainage ditch (7) is constructed below the bottom slab (11) of the new station on the side close to the existing station (1).

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