CN111305282A - Subway station anti-floating system in weak water-rich stratum and construction method thereof - Google Patents

Abstract

The invention discloses a subway station anti-floating system for a weak water-rich stratum and a construction method of the subway station anti-floating system, wherein the subway station anti-floating system comprises a station main body structure and an underground continuous wall, a continuous through long groove is formed in the inner side of the underground continuous wall, a vertical water-stop curtain is arranged on the outer side of the underground continuous wall, a horizontal water-stop curtain and an anti-pulling pile are arranged at the bottom of a foundation pit, a structural column of the station main body structure is arranged on the anti-pulling pile, a pile side reinforcing area is arranged on the periphery of the anti-pulling pile, an outer wall reinforcing area is arranged on the outer side of the underground continuous wall, an inner wall reinforcing area is arranged on the inner side of the underground continuous wall, the inner wall reinforcing area is arranged in the height range. According to the invention, through the embedded design and the arrangement of the reinforcing area, the subway station main structure and the enclosure structure are designed into a unified whole, the self weight of the structure is fully utilized, the side friction resistance of the enclosure structure can be increased, the anti-floating effect and the structural stability of the structure are improved, and the construction cost is greatly reduced.

Description

Anti-floating system and construction method of subway station in soft and water-rich stratum

technical field

The invention relates to the technical field of subway engineering construction, in particular to an anti-floating system for a subway station in a soft and water-rich stratum and a construction method thereof.

Background technique

In the construction of urban rail transit projects, anti-floating stability is one of the key technical issues in the design and construction process, especially in subway stations in soft and water-rich strata. Safety, especially the long-term stability of operations, has a greater impact. At present, the main anti-floating methods used in subway stations include uplift piles, capping beams, anti-floating anchors, etc. These structures significantly increase the cost of subway construction. In recent years, in the excavation of subway station foundation pits in soft and water-rich strata, underground diaphragm walls are widely used as enclosure structures, and the use of underground diaphragm walls and main structures to form a composite to resist floating together has become a new type of anti-floating method , making use of the self-weight of the underground diaphragm wall and the frictional resistance on both sides. However, in the existing technology, the underground diaphragm wall is constructed as a groove by means of mud wall protection, resulting in the existence of mud on the groove wall, which seriously affects the exertion of the ultimate lateral friction resistance of the soil on both sides of the diaphragm wall and reduces the anti-floating effect. In the existing construction technology, the connection between the underground diaphragm wall and the main subway structure is mainly connected by means of capping beams, the embedding of the main structure bottom plate and the anchoring of steel bars. However, these connection methods may cause the main structure of the station and the underground diaphragm wall to fail due to construction errors. It is completely coordinated and affects the anti-floating performance of the underground diaphragm wall. In addition, the foundational anti-floating properties of the temporary column structure are not effectively utilized.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an anti-floating system and a construction method for a subway station in a soft and water-rich stratum.

In order to achieve the above purpose, the technical scheme of the present invention is: an anti-floating system for a subway station in a weak and water-rich stratum, comprising a station main structure and an underground diaphragm wall, and the inner side of the underground diaphragm wall is reserved with each layer of structural plates corresponding to the main structure of the station. The trough members are connected end to end to form a continuous through-length groove, and the outer edge of each layer of structural plates is embedded in the corresponding continuous through-length groove; The bottom is provided with a horizontal water-stop curtain and an anti-uplift pile, and the outer edge of the horizontal water-stop curtain is connected to the inner side of the underground diaphragm wall; The pile side reinforcement area is formed; the outer side of the underground diaphragm wall is provided with an outer reinforcement area, and the outer wall reinforcement area is set within the height range from the upper end of the vertical water-stop curtain to the lower end of the underground diaphragm wall, and the inner side of the underground diaphragm wall is provided with an inner wall reinforcement area. The inner reinforcement area is set within the height range from the lower end of the underground diaphragm wall to the lower end of the structure floor. Both the inner reinforcement area and the outer reinforcement area of the wall are grouted to reinforce the soil; the upper part of the roof of the main structure of the station is provided with a cohesive soil backfill area.

An anti-floating construction method for a subway station in a weak and water-rich stratum, comprising the following steps:

1) Construction of vertical water-stop curtain

Before excavation of the foundation pit, use three-axis cement mixing piles or high-pressure rotary jetting piles to reinforce the soil on both sides of the underground diaphragm wall to form a vertical water-stop curtain;

2) Construction of underground diaphragm wall

The slotting machine is used to groov between the corresponding vertical water-stop curtains, the steel cage is lowered, and the concrete is poured to form an underground diaphragm wall; the inner side of the underground diaphragm wall is formed with continuous long grooves corresponding to each layer of structural plates of the main structure of the station; There are also reserved grouting conduits in the wall and grouting conduits outside the wall;

3) Dewatering well construction

Set up several dewatering wells in the foundation pit;

4) Soil reinforcement at the bottom of the foundation pit

Use triaxial cement mixing piles or rotary jetting piles to reinforce the water-rich soil within a depth range of 1m above the bottom of the foundation pit to 2m below the bottom of the foundation pit to form a horizontal water-stop curtain at the bottom of the foundation pit;

5) Construction of uplift piles and columns

Use bored cast-in-place piles to set uplift piles at the bottom of the foundation pit, reserve grouting pipes on the side of the piles in the uplift piles, and construct upright columns on the uplift piles;

6) Foundation pit dewatering and foundation pit excavation

After the groundwater level is lowered to at least 1m below the bottom of the foundation pit, the foundation pit is excavated to 1m above the bottom of the pit;

7) Secondary grouting reinforcement of the soil at the bottom of the pit

Insert a conduit at the bottom of the foundation pit, and carry out secondary grouting reinforcement for the soil within 2m below the bottom of the foundation pit;

8) Post grouting on the side of the anti-pull pile

Use the grouting pipe on the side of the pile to carry out high pressure grouting of the soil around the anti-pulling pile;

9) Soil grouting inside the underground diaphragm wall

Use the grouting conduit in the wall to carry out high pressure grouting on the wall side of the soil body on the inner side of the underground diaphragm wall below the bottom surface of the foundation pit;

10) Excavate the foundation pit to the bottom of the pit and construct the main structure of the station

After excavating the soil within 1m above the bottom of the foundation pit and inspecting the base, a waterproof layer is applied on the bottom surface of the foundation pit, and the structural slabs, walls, structural columns of the station main body are constructed layer by layer on the waterproof layer, and the structure of each layer is constructed. The outer edge of the plate is embedded in the corresponding continuous through-length groove;

11) Structural backfill

After the construction of the main structure of the station is completed, the upper part of the foundation pit shall be backfilled with cohesive soil;

12) Soil grouting outside the underground diaphragm wall

The high-pressure grouting on the outer side of the underground diaphragm wall and the vertical water-stop curtain is carried out by using the grouting conduit outside the wall.

As a preference of this solution, in step 1), the thickness of the vertical water-stop curtain is greater than or equal to 650mm, and the lower end enters the water-proof layer below the bottom surface of the foundation pit of not less than 2m.

As a preference of this solution, in step 2), the continuous continuous groove is formed by splicing groove-shaped members welded on the inner side of the reinforcement cage, the depth of the groove-shaped members is 20-30cm, and the outer opening of the groove is provided with an inverted horn.

As a preference of this solution, in step 2), the grouting conduit in the wall is bound on the side of the reinforcement cage of the underground diaphragm wall close to the inside of the foundation pit, and the grouting conduit outside the wall is bound on the side of the underground diaphragm wall. The side of the reinforcement cage close to the outside of the foundation pit; the distance between the grouting pipes in the wall and the horizontal distance between the grouting pipes outside the wall are both 2-3m; the grouting pipes in the wall and the grouting pipes outside the wall include vertically arranged pipes The lower end of the conduit is inserted into the bottom surface of the underground continuous wall, one side of the side wall of the conduit is provided with several upper connecting holes along its length direction, the upper connecting holes are spaced 2-3m apart, and the other side of the side wall of the conduit is provided with lower connecting holes corresponding to the upper connecting holes. Connecting holes, the lower connecting holes and the upper connecting holes are dislocated, and a grouting pipe is connected between the lower connecting hole and the upper connecting hole. The grouting pipe is bound on the steel cage of the underground diaphragm wall in an S shape. The grout outlet and the grout outlet are temporarily closed with tape. The grout outlet of the grouting conduit in the wall is opened towards the inside of the foundation pit, and the grout outlet of the grouting conduit outside the wall is opened towards the outside of the foundation pit; the grouting pipe of the grouting conduit outside the wall is opened. It is arranged in the range from 2m below the ground to the bottom of the underground diaphragm wall, and the grouting pipe of the grouting conduit in the wall is arranged in the range from the bottom of the foundation pit to the bottom of the underground diaphragm wall.

As a preference of this solution, in step 5), the length of the grouting conduit on the pile side exceeds the bottom surface of the foundation pit by not less than 1.5m.

As a preference of this solution, in step 9) and step 12), the high-pressure grouting process on the wall side is as follows: a single grouting conduit is used for multiple grouting, and after a grouting conduit is grouted The grouting shall be carried out at intervals of one grouting duct, and the grouting interval of two adjacent grouting ducts shall be no less than 24 hours, and the grouting pressure shall be controlled at 2-6Mpa.

As a preference of this solution, in step 10), the upright column is outsourced with reinforced concrete as the structural column of the main structure of the station.

The beneficial effects of the present invention are:

1. The present invention adopts the construction method of combining the vertical water-stop curtain and the horizontal water-stop curtain, which can significantly reduce the buoyancy on the bottom plate of the station structure.

2. The present invention adopts the construction method combining the side grouting of the underground diaphragm wall and the side grouting of the anti-uplift pile, which can significantly improve the anti-floating capacity of the station structure.

3. The present invention adopts the construction method of combining the underground diaphragm wall and the main structure of the station, which ensures the stability of the bottom of the foundation pit, and at the same time changes the temporary structure into a permanent anti-floating structure, and does not require additional anti-floating means. The anti-floating properties of the station structure also reduce costs.

4. The grooves of the present invention are provided with chamfers, which can ensure the effective connection between the underground diaphragm wall and the station structural plate, avoid the problem of insufficient connection thickness caused by the error of the hoisting position of the steel cage, and ensure the effective connection between the underground diaphragm wall and the station structural plate. lap.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Figure 2 is a schematic diagram of the installation of the grouting conduit outside the wall;

Figure 3 is a schematic diagram of the structure of the grouting pipe.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

As shown in Figure 1, an anti-floating system for a subway station in a weak and water-rich stratum includes a station main structure 1 and an underground diaphragm wall 2. The inner side of the underground diaphragm wall 2 is reserved with structural plates 3 corresponding to each layer of the station main structure 1. Horizontal channel members, the channel members are connected end to end to form a continuous through-length groove 4, and the outer edge of each layer of structural panels 3 is embedded in the corresponding continuous through-length groove 4; the outer side of the underground continuous wall 2 is provided with a vertical water-stop curtain 5. The bottom of the foundation pit 1 is provided with a horizontal water-stop curtain 6 and an anti-uplift pile 7, and the outer edge of the horizontal water-stop curtain 6 is connected to the inner side of the underground diaphragm wall 2; The soil around the uplift pile 7 is reinforced by grouting to form a pile side reinforcement area 9; the outer side of the underground diaphragm wall 2 is provided with an outer wall reinforcement area 10, and the outer wall reinforcement area 10 is arranged from the upper end of the vertical water-stop curtain 5 to the underground diaphragm wall 2. Within the height range of the lower end of the underground diaphragm wall 2, there is an inner wall reinforcement area 11 on the inner side. The inner wall reinforcement area 11 is set within the height range from the lower end of the underground diaphragm wall 2 to the lower end of the structural bottom plate 12. The inner wall reinforcement area 11 and the outer wall reinforcement area. 10 are grouting reinforcement soil; the upper part of the roof of the main structure of the station is provided with a cohesive soil backfill area 13.

The present invention designs the main structure of the subway station and the enclosure structure into a unified whole by embedding the design and setting the reinforcement area, making full use of the self-weight of the structure, increasing the side friction resistance of the enclosure structure, improving the anti-floating effect and the structural stability of the structure. And greatly reduce the project cost.

The following is a detailed description of the construction method of the above-mentioned anti-floating system, including the following steps:

1) Construction of vertical water-stop curtain

Before excavation of the foundation pit, three-axis cement mixing piles or high-pressure rotary jetting piles are used to reinforce the soil on both sides of the underground diaphragm wall to form a vertical water-stop curtain; the thickness of the vertical water-stop curtain is greater than or equal to 650mm, and the lower end enters the bottom surface of the foundation pit The following water barrier shall not be less than 2m.

2) Construction of underground diaphragm wall

The slotting machine is used to groov between the corresponding vertical water-stop curtains, the steel cage is lowered, and the concrete is poured to form an underground diaphragm wall; the inner side of the underground diaphragm wall is formed with continuous long grooves corresponding to each layer of structural plates of the main structure of the station; The continuous full-length groove is formed by splicing groove-shaped members welded on the inner side of the reinforcement cage. The depth of the groove-shaped members is 20-30cm, and the outer opening of the groove is provided with a chamfer; Grouting conduit outside the wall, as shown in Figure 2.

The in-wall grouting conduit is bound in the reinforcement cage of the underground diaphragm wall on the side close to the inside of the foundation pit, and the outer-wall grouting conduit is bound in the reinforcement cage of the underground diaphragm wall on the side close to the outside of the foundation pit; The distance between grouting pipes and the horizontal distance between grouting pipes outside the wall are both 2-3m; both the grouting pipes in the wall and the outside grouting pipes include vertically arranged pipes 101. The lower ends of the pipes 101 are inserted into the bottom of the underground diaphragm wall. One side of the side wall of 101 is provided with a plurality of upper connecting holes 102 along its length direction, the upper connecting holes 102 are spaced 2-3m apart, and the other side of the side wall of the conduit 101 is provided with lower connecting holes 103 corresponding to the upper connecting holes 102, and the lower connecting holes 102 are connected The hole 103 and the upper connecting hole 102 are arranged in a staggered position. A grouting pipe 104 is connected between the lower connecting hole 103 and the upper connecting hole 102. The grouting pipe 104 is bound in an S shape on the reinforcement cage of the underground diaphragm wall. Several slurry outlets 105, as shown in Figure 3, are temporarily closed with adhesive tape, the slurry outlet of the grouting conduit in the wall is opened towards the inside of the foundation pit, and the slurry outlet of the grouting conduit outside the wall is opened towards the outside of the foundation pit The grouting pipe of the grouting conduit outside the wall is arranged in the range below 2m from the ground to the bottom of the underground diaphragm wall, and the grouting pipe of the grouting conduit in the wall is arranged in the range from the bottom of the foundation pit to the bottom of the underground diaphragm wall.

In the traditional grouting process, the grouting conduit and the grouting pipe are connected in a one-way manner. During the grouting process, the grouting pipe is easily blocked, and the overlapping area between the grouting pipes is small, which makes the slurry distribution uneven. The grouting effect is not good. The invention connects the two ends of the grouting pipe to the grouting pipe, which can effectively prevent the blockage of the grouting pipe and ensure the smoothness of the grouting pipe. Moreover, the grouting pipe is arranged in an S shape, and the overlapping area between the grouting pipes can be produced, thereby Guaranteed grouting effect.

3) Dewatering well construction

Set up several dewatering wells in the foundation pit.

4) Soil reinforcement at the bottom of the foundation pit

Three-axis cement mixing piles or rotary jetting piles are used to reinforce the water-rich soil within a depth range of 1m above the bottom of the foundation pit to 2m below the bottom of the foundation pit to form a horizontal water-stop curtain at the bottom of the foundation pit.

5) Construction of uplift piles and columns

Bored piles are used to set uplift piles at the bottom of the foundation pit. The pile side grouting pipes are reserved in the uplift piles. The pile side grouting pipes are arranged along the entire length of the uplift piles, and the length of the pile side grouting pipes exceeds the bottom surface of the foundation pit. Not less than 1.5m; construct upright columns on uplift piles.

6) Foundation pit dewatering and foundation pit excavation

After the groundwater level is lowered to at least 1m below the bottom of the foundation pit, the foundation pit is excavated to 1m above the bottom of the pit.

7) Secondary grouting reinforcement of the soil at the bottom of the pit

A conduit is inserted at the bottom of the foundation pit, and the soil within a range of 2m below the bottom of the foundation pit is reinforced by secondary grouting.

8) Post grouting on the side of the anti-pull pile

Use the grouting pipe on the side of the pile to perform high pressure grouting on the soil around the anti-pulling pile.

9) Soil grouting inside the underground diaphragm wall

Use the grouting conduit in the wall to carry out high pressure grouting on the wall side of the soil body on the inner side of the underground diaphragm wall below the bottom surface of the foundation pit.

10) Excavate the foundation pit to the bottom of the pit and construct the main structure of the station

After excavating the soil within 1m above the bottom of the foundation pit and inspecting the base, a waterproof layer is applied on the bottom surface of the foundation pit, and the structural slabs, walls, structural columns of the station main body are constructed layer by layer on the waterproof layer, and the structure of each layer is constructed. The outer edge of the plate is embedded in the corresponding continuous full-length groove; the column is outsourced with reinforced concrete as the structural column of the main structure of the station.

11) Structural backfill

After the construction of the main structure of the station is completed, the upper part of the foundation pit will be backfilled with cohesive soil.

12) Soil grouting outside the underground diaphragm wall

The high-pressure grouting on the outer side of the underground diaphragm wall and the vertical water-stop curtain is carried out by using the grouting conduit outside the wall.

The high-pressure grouting process on the wall side is as follows: a single grouting duct is used for multiple grouting. The grouting interval is not less than 24 hours, and the grouting pressure is controlled at 2-6Mpa.

The described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of the present invention.

Claims (8)

1. an anti-floating system for a subway station in a weak water-rich stratum, characterized in that it comprises a station main structure, an underground diaphragm wall, and the inner side of the underground diaphragm wall is reserved with horizontal trough members corresponding to each layer of structural plates of the station main structure The trough members are connected end to end to form a continuous through-length groove, and the outer edge of each layer of structural plates is embedded in the corresponding continuous through-length groove; the outer side of the underground continuous wall is provided with a vertical water-stop curtain, and the bottom of the foundation pit is provided with a horizontal water-stop Curtain and uplift piles, the outer edge of the horizontal water-stop curtain is connected to the inner side of the underground diaphragm wall; the structural columns of the main structure of the station are set on the uplift piles, and the soil around the uplift piles is reinforced by grouting to form a pile side reinforcement area; The outer side of the underground diaphragm wall is provided with an outer wall reinforcement area, and the outer wall reinforcement area is set within the height range from the upper end of the vertical water-stop curtain to the lower end of the underground diaphragm wall. Within the height range from the lower end of the diaphragm wall to the lower end of the structural floor, the reinforcement area inside the wall and the reinforcement area outside the wall are both grouting reinforcement soil; the upper part of the roof of the main structure of the station is provided with a cohesive soil backfill area. 2. An anti-floating construction method for a subway station in a weak and water-rich stratum, characterized in that it comprises the following steps: 1) Construction of vertical water-stop curtain Before excavation of the foundation pit, use three-axis cement mixing piles or high-pressure rotary jetting piles to reinforce the soil on both sides of the underground diaphragm wall to form a vertical water-stop curtain; 2) Construction of underground diaphragm wall The slotting machine is used to groov between the corresponding vertical water-stop curtains, the steel cage is lowered, and the concrete is poured to form an underground diaphragm wall; the inner side of the underground diaphragm wall is formed with continuous long grooves corresponding to each layer of structural plates of the main structure of the station; There are also reserved grouting conduits in the wall and grouting conduits outside the wall; 3) Dewatering well construction Set up several dewatering wells in the foundation pit; 4) Soil reinforcement at the bottom of the foundation pit Use triaxial cement mixing piles or rotary jetting piles to reinforce the water-rich soil within a depth range of 1m above the bottom of the foundation pit to 2m below the bottom of the foundation pit to form a horizontal water-stop curtain at the bottom of the foundation pit; 5) Construction of uplift piles and columns Use bored cast-in-place piles to set uplift piles at the bottom of the foundation pit, reserve grouting pipes on the side of the piles in the uplift piles, and construct upright columns on the uplift piles; 6) Foundation pit dewatering and foundation pit excavation After the groundwater level is lowered to at least 1m below the bottom of the foundation pit, the foundation pit is excavated to 1m above the bottom of the pit; 7) Secondary grouting reinforcement of the soil at the bottom of the pit Insert a conduit at the bottom of the foundation pit, and carry out secondary grouting reinforcement for the soil within 2m below the bottom of the foundation pit; 8) Post grouting on the side of the anti-pull pile Use the grouting pipe on the side of the pile to carry out high pressure grouting of the soil around the anti-pulling pile; 9) Soil grouting inside the underground diaphragm wall Use the grouting conduit in the wall to carry out high pressure grouting on the wall side of the soil body on the inner side of the underground diaphragm wall below the bottom surface of the foundation pit; 10) Excavate the foundation pit to the bottom of the pit and construct the main structure of the station After excavating the soil within 1m above the bottom of the foundation pit and inspecting the base, a waterproof layer is applied on the bottom surface of the foundation pit, and the structural slabs, walls, structural columns of the station main body are constructed layer by layer on the waterproof layer, and the structure of each layer is constructed. The outer edge of the plate is embedded in the corresponding continuous through-length groove; 11) Structural backfill After the construction of the main body of the station structure is completed, the upper part of the foundation pit shall be backfilled with cohesive soil; 12) Soil grouting outside the underground diaphragm wall Use the grouting conduit outside the wall to carry out high-pressure grouting on the outer side of the underground diaphragm wall and the vertical water-stop curtain. 3. The anti-floating construction method for a subway station in a weak water-rich stratum according to claim 1, characterized in that, in step 1), the thickness of the vertical water-stop curtain is greater than or equal to 650mm, and the lower end enters the bottom surface of the foundation pit. The water barrier shall not be less than 2m. 4. The anti-floating construction method for a subway station in a weak and water-rich stratum according to claim 1, wherein in step 2), the continuous long grooves are spliced by trough-shaped members welded on the inner side of the reinforcement cage. The groove-shaped member has a depth of 20-30cm, and the outer opening of the groove is provided with a chamfer. 5. The anti-floating construction method for a subway station in a weak and water-rich stratum according to claim 1, wherein in step 2), the grouting conduit in the wall is bound in the reinforcement cage of the underground diaphragm wall near the foundation pit On the inner side, the grouting conduit outside the wall is bound in the reinforcement cage of the underground diaphragm wall on the side close to the outside of the foundation pit; the distance between the grouting conduits in the wall and the horizontal distance between the grouting conduits outside the wall are both 2-3m; Both the grouting conduit in the wall and the grouting conduit outside the wall include vertically arranged conduits. The lower ends of the conduits are inserted into the bottom surface of the underground continuous wall. A number of upper connecting holes are arranged on one side of the side wall of the conduit along the length direction, and the upper connecting holes are spaced 2 -3m, the other side of the side wall of the conduit is provided with a lower connection hole corresponding to the upper connection hole, the lower connection hole and the upper connection hole are arranged in dislocation, and a grouting pipe is connected between the lower connection hole and the upper connection hole, and the grouting pipe is S The grouting pipe is provided with a number of grouting outlets, which are temporarily closed with adhesive tape. The grouting conduit in the wall is opened towards the inside of the foundation pit, and the grouting conduit outside the wall is open. The grouting outlet is opened towards the outside of the foundation pit; the grouting pipe of the grouting conduit outside the wall is arranged in the range from 2m below the ground to the bottom of the underground diaphragm wall, and the grouting pipe of the grouting conduit in the wall is arranged from the bottom of the foundation pit to the bottom of the underground diaphragm wall within the range. 6. The anti-floating construction method for a subway station in a weak and water-rich stratum according to claim 1, wherein in step 5), the grouting conduit on the side of the pile is arranged along the full length of the uplift pile, and the upper part exceeds the foundation. The bottom of the pit shall not be less than 1.5m. 7. The anti-floating construction method for a subway station in a weak and water-rich stratum according to claim 1, in steps 9) and 12), the high-pressure grouting process on the wall side is: using a single grouting conduit for multiple injections. In the grouting method, after a grouting pipe is grouted, a grouting pipe is used for grouting, and the grouting interval of two adjacent grouting pipes is not less than 24 hours, and the grouting pressure is controlled at 2-6Mpa. . 8 . The anti-floating construction method for a subway station in a weak and water-rich stratum according to claim 1 , wherein in step 10 ), the uprights are outsourced with reinforced concrete as the structural columns of the main structure of the station. 9 .

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