阅读说明：本技术 岩石地层洞桩法车站主体结构施工方法 (Construction method of main structure of station by rock stratum hole-pile method ) 是由 唐雄 李学友 熊志富 唐贤金 唐能谋 姚泽善 于 2021-09-06 设计创作，主要内容包括：本发明提供了一种岩石地层洞桩法车站主体结构施工方法,包括边纵梁施工、中纵梁施工、中拱及第二边拱施工、中拱及边拱二衬施工、轨顶风道及中板施工、底板施工和主体侧墙施工。本发明将侧墙后做,即完成车站主体结构中中板和底板施工后再进行侧墙施工,且侧墙按照顺作法施工,可在施工过程中保证中板的施工质量,增加其稳定性,即其不会在其重力的作用下在竖直方向出现位置变化或者形变,从而在对站厅层侧墙提供支撑的同时避免了站厅层侧墙上施工缝被拉裂,保证了车站的防水性能。(The invention provides a construction method of a main structure of a station by a rock stratum hole pile method, which comprises side longitudinal beam construction, middle arch and second side arch construction, middle arch and side arch second lining construction, rail top air duct and middle plate construction, bottom plate construction and main body side wall construction. According to the invention, the side wall is manufactured later, namely the construction of the middle plate and the bottom plate in the main structure of the station is completed, then the side wall construction is carried out, and the side wall is constructed according to a sequential construction method, so that the construction quality of the middle plate can be ensured in the construction process, the stability of the middle plate is improved, namely the middle plate can not be changed in position or deformed in the vertical direction under the action of gravity, and therefore, the side wall of the station hall layer is supported, meanwhile, the construction joint on the side wall of the station hall layer is prevented from being pulled apart, and the waterproof performance of the station is ensured.)

1. A construction method of a main structure of a station by a rock stratum hole pile method is characterized by comprising the following steps: the method comprises the following steps:

s1, side longitudinal beam construction: erecting an edge arch grid steel frame in a first pilot tunnel (I) and a fourth pilot tunnel (IV), erecting a mould below the edge arch grid steel frame, spraying concrete of a first edge arch primary support (11), and backfilling the outer space of the first edge arch primary support (11) in the first pilot tunnel (I) and the fourth pilot tunnel (IV) by using plain concrete;

s2, middle longitudinal beam construction: in the vertical formwork construction of a second pilot tunnel (II) and a third pilot tunnel (III), a middle longitudinal beam (6) is provided with a steel bar joint in advance, and then a gap between the second pilot tunnel (II) and the middle longitudinal beam (6) inside the second pilot tunnel and a gap between the third pilot tunnel (III) and the middle longitudinal beam (6) inside the third pilot tunnel are backfilled with plain concrete;

s3, constructing the middle arch and the second side arch: excavating an arch-centering soil body and a second side arch soil body, and respectively constructing an arch-centering primary support (13) and a second side arch primary support (12);

s4, middle arch and side arch second lining construction: dismantling the side walls of the first pilot tunnel (I), the second pilot tunnel (II), the third pilot tunnel (III) and the fourth pilot tunnel (IV) and the side arch grid steel frame, respectively constructing a secondary lining for the middle arch primary support (13), the first side arch primary support (11) and the second side arch primary support (12) to form a middle arch secondary lining (7) and a side arch secondary lining (5), and respectively connecting the steel bar joint with the middle arch secondary lining (7) and the side arch secondary lining (5);

s5, constructing a rail top air channel and a middle plate: excavating a main body soil body to be below the bottom surface of a preset rail top air channel along the axial direction of a middle pile (9) and a side pile (2) at the bottoms of the first pilot tunnel (I), the second pilot tunnel (II), the third pilot tunnel (III) and the fourth pilot tunnel (IV), pouring a cushion layer below the rail top air channel, and then pouring a lower plate (15) of the rail top air channel through a vertical mold and reserving reinforcing steel bars of a side plate (14) of the rail top air channel; binding reinforcing steel bars of the rail top air duct side plate (14), erecting a mold to pour the rail top air duct side plate (14), then binding reinforcing steel bars of the middle plate (8), arranging vertical ribs of the main body side wall (3), connecting the upper ends of the vertical ribs to the side longitudinal beam (4), connecting the lower ends of the vertical ribs to the reinforcing steel bars of the middle plate (8), and erecting the mold to finish pouring of the middle plate (8);

s6, bottom plate construction: excavating a soil body below the middle plate (8) along the axial direction of the middle piles (9) and the side piles (2) to a preset depth of the base, then constructing anchor rods and primary supports of the main body side walls (3), constructing a current ground net, laying a waterproof layer of the bottom plate (1) and pouring the bottom plate (1);

s7, main body side wall construction: the main body side wall (3) below the middle plate (8) is constructed firstly, and then the main body side wall (3) above the middle plate (8) is constructed.

2. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 1, characterized in that: in S1, the side member (4) is cast in sections along the longitudinal direction thereof.

3. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 1, characterized in that: in the step S2, before the gap between the second pilot hole (ii) and the middle longitudinal beam (6) inside the second pilot hole and the gap between the third pilot hole (iii) and the middle longitudinal beam (6) inside the third pilot hole are backfilled with plain concrete, a middle longitudinal beam (6) waterproof layer is laid on the top of the middle longitudinal beam (6).

4. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 1, characterized in that: in S3, when the arch soil and the second side arch soil are excavated, the arch soil is excavated, and after the excavation depth of the arch soil reaches 15 to 20m, the second side arch soil on both sides of the arch starts to be excavated symmetrically.

5. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 1, characterized in that: and in S4, removing the side walls of the first pilot tunnel (I), the second pilot tunnel (II), the third pilot tunnel (III) and the fourth pilot tunnel (IV) and the side arch grid steel frame, removing the concrete of the first side arch primary support (11) in the first pilot tunnel (I) and the fourth pilot tunnel (IV), paving a vault waterproof layer on the inner side surface of the middle arch primary support (13), the first side arch primary support (11), the second side arch primary support (12) and the middle arch primary support (13), binding the second lining steel bars and connecting the second lining steel bars with the steel bar joint, and then finishing pouring of the second lining at the position of the second lining steel bars.

6. The construction method of a main body structure of a station in a rock stratum hole pile method according to claim 5, characterized in that: dividing the first side arch primary support (11) into a plurality of sections which are connected in sequence according to a mode of extending along the length direction of the first pilot tunnel (I) and the fourth pilot tunnel (IV), firstly breaking off concrete of one section of the first side arch primary support (11) and completing secondary lining construction of the first side arch primary support, and then sequentially carrying out secondary lining construction of the next section of the first side arch primary support (11) adjacent to the first side arch primary support;

a first construction gap is formed between the second lining on the first side arch primary support (11) of one section and the first side arch primary support (11) of the next section adjacent to the second lining.

7. The construction method of a main body structure of a station in a rock stratum hole pile method according to claim 5, characterized in that: dividing the middle arch primary support (13) into a plurality of sections which are connected in sequence in a manner of extending along the length direction of the second pilot tunnel (II) and the third pilot tunnel (III), firstly removing concrete of one section of the middle arch primary support (13) and completing secondary lining construction of the middle arch primary support, and then sequentially carrying out secondary lining construction of the next section of the middle arch primary support (13) adjacent to the middle arch primary support;

and a second construction gap is formed between the second lining on one section of the middle arch primary support (13) and the next section of the middle arch primary support (13) adjacent to the second lining.

8. The construction method of a rock stratum hole pile method station main body structure according to any one of claims 5 to 7, characterized by comprising: firstly, constructing the middle arch second lining (7), and then constructing the first side arch primary support (11) second lining and the second side arch primary support (12) second lining.

9. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 1, characterized in that: the S5 includes the steps of:

s51, completely removing the remaining first side arch primary support (11) in the first pilot tunnel (I) and the fourth pilot tunnel (IV);

s52, excavating soil bodies below the first pilot tunnel (I), the second pilot tunnel (II), the third pilot tunnel (III) and the fourth pilot tunnel (IV) by adopting segmented layering, constructing a net among the side piles (2) along with excavation of the soil bodies, and spraying concrete;

s53, when the main body soil body is integrally excavated to be close to the designed elevation of the bottom soil mold of the rail top air channel, the control of the excavation elevation is strengthened, a soil layer with the thickness of 30cm is reserved for manual bottom cleaning, and overexcavation is strictly prohibited;

s54, after the track top air channel is excavated to the designed elevation, firstly, a lower plate (15) of the track top air channel is poured, and reinforcing steel bars of a side plate (14) of the track top air channel are reserved;

s55, after the lower plate (15) is poured, erecting a support template of the middle plate (8) by relying on the lower plate (15), binding reinforcing steel bars of the rail top air channel side plate (14), and pouring the rail top air channel side plate (14) by erecting a mold;

s56, binding the middle plate (8) and the reinforcing steel bars of the middle longitudinal beam (6), arranging vertical ribs of the main body side wall (3), connecting the upper ends of the vertical ribs to the side longitudinal beam (4), connecting the lower ends of the vertical ribs to the reinforcing steel bars of the middle plate (8), and finishing pouring of the middle plate (8).

10. The construction method of a main body structure of a rock stratum hole pile method station as claimed in claim 8, characterized in that: the construction joint of main part side wall (3) and this medium plate (8) of medium plate (8) below is the oblique joint, construction joint department adopts fine sand backfill closely knit.

Technical Field

The invention relates to the technical field of subway station construction, in particular to a method for constructing a main structure of a station by a rock stratum hole-pile method.

Background

The hole pile method is also called PBA method, is a type of shallow buried underground excavation method, and is an important construction method for subway station construction. The method utilizes a small pilot tunnel to construct a pile beam to form a main force transmission structure, and inner pit excavation is carried out under a subsurface excavation arch cover. The method is used for the first time when a Beijing subway No. 1 linedong single station is built in 1992, compared with other types of shallow buried underground excavation methods, the hole-pile method has the advantages of being capable of effectively controlling ground surface settlement, high in construction efficiency, flexible in structural form, high in space utilization rate and the like, and along with the rapid development of urban rail transit construction in China, the application of the hole-pile method underground excavation station is more and more wide, a large amount of engineering practice and theoretical research are carried out, the hole-pile method underground excavation station construction technology is continuously improved, the application range is further expanded, the problems of traffic guidance, pipeline improvement, house removal and the like in subway station building in cities are well solved, and huge social and economic benefits are created.

As shown in fig. 7, the major structure of station includes two sets of limit stake that the left and right sides symmetry set up, and the quantity of every group limit stake is a plurality of, and this a plurality of limit stake evenly extends the setting along station length direction, sets up two sets of well stakes according to the mode that extends from left to right in the middle of the two sets of limit stakes, and the quantity of stake is a plurality of in every group, and the stake evenly extends the setting along the length direction of station in this a plurality of. The side longitudinal beams erected at the tops of the side piles of each group are connected with each other, and the middle piles of each group are connected with each other through the middle longitudinal beams erected at the tops of the middle piles. The side longitudinal beams and the middle longitudinal beams are connected through side arches, and the left and right adjacent middle longitudinal beams are connected through middle arches. The side arches and the middle arch are matched with the middle longitudinal beam and the side longitudinal beam to form a top structure of the station main body structure. The station main structure further comprises a middle plate and a bottom plate which are sequentially arranged along the axial direction of the middle pile. The middle pile and the side pile are both vertically arranged. Side walls are arranged between the middle plate and the bottom plate and close to the side piles, and between the middle plate and the side longitudinal beams and close to the side piles. The bottom plate, the side walls, the side longitudinal beams, the side arches, the middle longitudinal beams and the middle arches form a closed station main body structure, and the middle plate separates the main body structure in the longitudinal direction to realize spatial layering. The lower surface of medium plate is provided with the rail top wind channel. When adopting the hole stake method to carry out construction to above-mentioned structure, at first set up four pilot holes as shown in fig. 2, turn right from left and be first pilot hole, second pilot hole, third pilot hole and fourth pilot hole in proper order, execute in the pilot hole afterwards and make the side longeron, well longeron, side pile and well stake etc. specifically, construct the side pile along vertical direction in first pilot hole and fourth pilot hole, construct the side longeron at side pile top afterwards, in second and third pilot hole along vertical direction construction well stake, longeron in well stake top construction afterwards.

However, when each part of the structure is constructed, because the construction sequence is different, construction joints are inevitably generated at the joints of the same part or different parts, especially the construction joints between the side walls and the frame beams and between the side walls and the middle plates, and because the side walls are under the action of the self-weight of the side walls in the vertical direction, the construction joints between the side walls and the side longitudinal beams and between the side walls and the middle plates are easy to be pulled apart, so that the waterproof performance of the station is poor, and the construction quality of the station is affected.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for constructing a station main body structure by a rock stratum hole pile method.

The embodiment of the invention is realized by the following technical scheme:

a construction method of a main structure of a station by a rock stratum hole pile method comprises the following steps:

s1, side longitudinal beam construction: erecting an edge arch grid steel frame in a first pilot tunnel and a fourth pilot tunnel, erecting a mould below the edge arch grid steel frame, spraying first edge arch primary support concrete, and backfilling the outer space of each first edge arch primary support in the first pilot tunnel and the fourth pilot tunnel by using plain concrete;

s2, middle longitudinal beam construction: in the construction of a second pilot hole and a third pilot hole vertical mold, reserving a steel bar joint on a middle longitudinal beam, and then backfilling a gap between the second pilot hole and the middle longitudinal beam inside the second pilot hole and a gap between the third pilot hole and the middle longitudinal beam inside the third pilot hole by using plain concrete;

s3, constructing the middle arch and the second side arch: excavating an arch-in soil body and a second side arch soil body, and respectively constructing an arch-in primary support and a second side arch primary support;

s4, middle arch and side arch second lining construction: removing the side walls of the first pilot tunnel, the second pilot tunnel, the third pilot tunnel and the fourth pilot tunnel and the side arch grid steel frame, respectively applying second linings to the primary middle arch support, the primary first side arch support and the primary second side arch support to form a secondary middle arch lining and a secondary side arch lining, and respectively connecting the steel bar joints with the secondary middle arch lining and the secondary side arch lining;

s5, constructing a rail top air channel and a middle plate: excavating a main body soil body to be below the bottom surface of a preset rail top air duct along the axial direction of a middle pile and a side pile at the bottoms of the first pilot tunnel, the second pilot tunnel, the third pilot tunnel and the fourth pilot tunnel, pouring a cushion layer below the rail top air duct, and then pouring a lower plate of the rail top air duct and reserving reinforcing steel bars of a side plate of the rail top air duct by using a vertical mold; binding reinforcing steel bars of the rail top air duct side plate, erecting a mold to pour the rail top air duct side plate, then binding middle plate reinforcing steel bars, arranging vertical ribs of a main body side wall, connecting the upper ends of the vertical ribs to the side longitudinal beams, connecting the lower ends of the vertical ribs to the middle plate reinforcing steel bars, and erecting the mold to finish pouring the middle plate;

s6, bottom plate construction: excavating a soil body to a preset base position depth along the axial direction of the middle pile and the side pile below the middle plate, then constructing an anchor rod and a primary support of the main body side wall, constructing a current ground net, laying a bottom plate waterproof layer and pouring the bottom plate;

s7, main body side wall construction: and constructing the main body side wall below the middle plate firstly, and constructing the main body side wall above the middle plate later.

According to a preferred embodiment, in S1, the side frame is cast in sections along the length direction of the side frame.

According to a preferred embodiment, in S2, before the gaps between the second pilot hole and the middle longitudinal beam inside thereof and the gaps between the third pilot hole and the middle longitudinal beam inside thereof are backfilled with plain concrete, a middle longitudinal beam waterproof layer is laid on the top of the middle longitudinal beam.

According to a preferred embodiment, in the step S3, the middle arch soil body and the second side arch soil body are excavated, the middle arch soil body is excavated, and after the excavation depth of the middle arch soil body reaches 15-20m, the second side arch soil bodies on both sides of the middle arch start to be excavated symmetrically.

According to a preferred embodiment, in S4, removing the side walls of the first pilot tunnel, the second pilot tunnel, the third pilot tunnel and the fourth pilot tunnel and the side arch grid steel frame, breaking the first side arch primary support concrete in the first pilot tunnel and the fourth pilot tunnel, laying a vault waterproof layer on the inner side surfaces of the middle arch primary support, the first side arch primary support, the second side arch primary support and the middle arch primary support, binding the two lining steel bars and connecting the two lining steel bars with the steel bar joints, and then completing casting of the two linings at the positions of the two lining steel bars.

According to a preferred embodiment, the first side arch primary support is divided into a plurality of sections which are connected in sequence in a mode of extending along the length direction of the first pilot tunnel and the fourth pilot tunnel, firstly, the first side arch primary support concrete of one section is broken and secondary lining construction is completed, and then secondary lining construction of the first side arch primary support of the next section adjacent to the first side arch primary support is sequentially carried out; and a first construction gap is formed between the second lining on the first side arch primary support of one section and the first side arch primary support of the next section adjacent to the second lining.

According to a preferred embodiment, the middle arch primary support is divided into a plurality of sections which are connected in sequence in a mode of extending along the length direction of the second pilot tunnel and the third pilot tunnel, firstly, the concrete of one section of the middle arch primary support is broken and secondary lining construction is completed, and then secondary lining construction of the next section of the middle arch primary support adjacent to the concrete of the other section of the middle arch primary support is sequentially carried out; and a second construction gap is formed between the second lining on one section of the middle arch primary support and the next section of the middle arch primary support adjacent to the second lining.

According to a preferred embodiment, the construction of the middle arch secondary lining is performed first, and then the construction of the first side arch primary secondary lining and the second side arch primary secondary lining are performed.

According to a preferred embodiment, the S5 includes the following steps:

s51, completely removing the remaining first side arch primary supports in the first pilot tunnel and the fourth pilot tunnel;

s52, excavating soil bodies below the first pilot tunnel, the second pilot tunnel, the third pilot tunnel and the fourth pilot tunnel by adopting segmented layering, constructing a net among side pile piles along with the excavation of the soil bodies, and spraying concrete;

s53, when the main body soil body is integrally excavated to be close to the designed elevation of the bottom soil mold of the rail top air channel, the control of the excavation elevation is strengthened, a soil layer with the thickness of 30cm is reserved for manual bottom cleaning, and overexcavation is strictly prohibited;

s54, after the track is excavated to the designed elevation, firstly, pouring a lower plate of the track top air channel and reserving reinforcing steel bars of a side plate of the track top air channel;

s55, after the lower plate is poured, erecting the middle plate support template by relying on the lower plate, binding the reinforcing steel bars of the rail top air channel side plate and erecting a mold to pour the rail top air channel side plate;

and S56, binding the middle plate and the reinforcing steel bars of the middle longitudinal beam, arranging vertical ribs of the main body side wall, connecting the upper ends of the vertical ribs to the side longitudinal beams, connecting the lower ends of the vertical ribs to the reinforcing steel bars of the middle plate, and finishing pouring of the middle plate.

According to a preferred embodiment, the construction joint between the main body side wall below the middle plate and the middle plate is an inclined joint, and the construction joint is densely backfilled by fine sand.

The technical scheme of the embodiment of the invention at least has the following advantages and beneficial effects:

according to the invention, the side wall is manufactured later, namely the construction of the middle plate and the bottom plate in the main structure of the station is completed, then the side wall construction is carried out, and the side wall is constructed according to a sequential construction method, so that the construction quality of the middle plate can be ensured in the construction process, the stability of the middle plate is improved, namely the middle plate can not be changed in position or deformed in the vertical direction under the action of gravity, and therefore, the side wall of the station hall layer is supported, meanwhile, the construction joint on the side wall of the station hall layer is prevented from being pulled apart, and the waterproof performance of the station is ensured.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a block diagram of a construction process of the present invention;

FIG. 2 is a schematic structural view of the side and middle longitudinal beams of the present invention after completion of construction;

FIG. 3 is a schematic structural view of the middle arch and the second side arch after the construction is completed;

FIG. 4 is a schematic structural view of the arch and side arch of the present invention after the construction of the second liner;

FIG. 5 is a schematic structural diagram of the track top duct and the middle plate after the construction is completed;

FIG. 6 is a schematic structural view of the bottom plate of the present invention after completion of construction;

fig. 7 is a schematic structural view of the main body side wall after the construction is completed.

Icon: 1-bottom plate, 2-side pile, 3-main body side wall, 31-hall layer side wall, 32-platform layer side wall, 4-side longitudinal beam, 5-side arch secondary lining, 6-middle longitudinal beam, 7-middle arch secondary lining, 8-middle plate, 9-middle pile, 10-station plate, 11-first side arch primary support, 12-second side arch primary support, 13-middle arch primary support, 14-side plate, 15-lower plate, I-first pilot hole, II-second pilot hole, III-third pilot hole and IV-fourth pilot hole.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are usually placed in when used, the terms are only used for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1 to 7, a method for constructing a main structure of a station by a rock stratum hole-pile method includes the following steps:

s1, side longitudinal beam construction: erecting an edge arch grid steel frame in the first pilot hole I and the fourth pilot hole IV, erecting a mould below the edge arch grid steel frame, spraying first edge arch primary support 11 concrete, and backfilling the outer space of the first edge arch primary support 11 in the first pilot hole I and the fourth pilot hole IV respectively with plain concrete. Further, in S1, the side member 4 is cast in sections along the longitudinal direction thereof. Specifically, in this embodiment, the side stringers 4 have a dimension of 1700mm × 1700mm, and have a total length of 550 m. The method adopts segmented pouring, each segment is planned to be 9 meters long, 2-3 segments can be poured at one time according to actual conditions on site, continuous pouring is carried out, C35 commercial concrete is adopted, and the concrete is pumped into a mold.

S2, middle longitudinal beam construction: and (3) reserving a steel bar joint on the middle longitudinal beam 6 in the vertical formwork construction of the second pilot hole II and the third pilot hole III, and then backfilling a gap between the second pilot hole II and the middle longitudinal beam 6 inside the second pilot hole II and a gap between the third pilot hole III and the middle longitudinal beam 6 inside the third pilot hole III by using plain concrete. In the embodiment, the section of the middle longitudinal beam 6 is a special-shaped reinforced concrete structure with the size of 1600mm multiplied by 2600 mm. Further, in S2, before the gap between the second pilot hole ii and the inner center side member 6 and the gap between the third pilot hole iii and the inner center side member 6 are filled with plain concrete, a waterproof layer for the center side member 6 is laid on the top of the center side member 6. The structure after the construction is completed is shown in fig. 2.

S3, constructing the middle arch and the second side arch: excavating the middle arch soil body and the second side arch soil body, and respectively constructing a middle arch primary support 13 and a second side arch primary support 12. Further, in S3, when excavating, the middle arch soil and the second side arch soil are firstly excavated, and after the excavation depth of the middle arch soil reaches 15-20m, the second side arch soil at two sides of the middle arch begins to be excavated symmetrically. The structure after the construction is completed is shown in fig. 3.

S4, middle arch and side arch second lining construction: and (3) dismantling side walls and side arch grid steel frames of the first pilot tunnel I, the second pilot tunnel II, the third pilot tunnel III and the fourth pilot tunnel IV, respectively constructing two linings on the middle arch primary support 13, the first side arch primary support 11 and the second side arch primary support 12 to form a middle arch secondary lining 7 and a side arch secondary lining 5, and respectively connecting the steel bar joint with the middle arch secondary lining 7 and the side arch secondary lining 5. In this embodiment, the second side arch support 5 is formed by a second first side arch support 11 and a second side arch support 12. Further, in S4, removing side walls and side arch grid steel frames of the first pilot tunnel I, the second pilot tunnel II, the third pilot tunnel III and the fourth pilot tunnel IV, breaking the concrete of the first side arch primary support 11 in the first pilot tunnel I and the fourth pilot tunnel IV, paving arch crown waterproof layers on the inner side surfaces of the middle arch primary support 13, the first side arch primary support 11, the second side arch primary support 12 and the middle arch primary support 13, binding second lining reinforcing steel bars, connecting the second lining reinforcing steel bars with reinforcing steel bar joints, and then finishing pouring of a second lining at the position of the second lining reinforcing steel bars. After the side wall of the pilot tunnel is broken, the first side arch primary support 11 and the second side arch primary support 12 are connected into an integral arc-shaped side arch, one end of a constructed side arch secondary lining 5 is connected to the side longitudinal beam 4, the other end of the constructed side arch secondary lining is connected to the middle longitudinal beam 6, and the middle arch secondary lining 7 connects two adjacent middle longitudinal beams 6, so that a closed structure is formed at the top of the station main body structure. The structure after the construction is completed is shown in fig. 4.

In this embodiment, the first side arch primary support 11 is divided into a plurality of sections connected in sequence in a manner of extending along the length direction of the first pilot tunnel i and the fourth pilot tunnel iv, the concrete of one section of the first side arch primary support 11 is broken and the second lining construction is completed, and then the second lining construction of the next section of the first side arch primary support 11 adjacent to the first side arch primary support is sequentially performed, wherein a first construction gap is formed between the second lining on one section of the first side arch primary support 11 and the next section of the first side arch primary support 11 adjacent to the second side arch primary support. Dividing the middle arch primary support 13 into a plurality of sections which are connected in sequence according to a mode of extending along the length direction of the second pilot tunnel II and the third pilot tunnel III, firstly breaking off concrete of one section of the middle arch primary support 13 and completing secondary lining construction of the middle arch primary support, and then sequentially carrying out secondary lining construction of the next section of the middle arch primary support 13 adjacent to the middle arch primary support, wherein a second construction gap is formed between the secondary lining on one section of the middle arch primary support 13 and the next section of the middle arch primary support 13 adjacent to the middle arch primary support. Specifically, the first section has a breaking length of 12m, and the rest of the primary support concrete with a length of 9m is broken once every pouring. Preferably, the construction of the middle arch second lining 7 is firstly carried out, and then the construction of the first side arch primary support 11 second lining and the second side arch primary support 12 second lining are carried out. In this embodiment, the first construction gap and the second construction gap are both convenient for breaking the next section of primary concrete, that is, the length of the second lining construction of each section lags behind the length of the primary concrete breaking of the corresponding section. In this embodiment, preferably, the second lining construction is performed in a manner that the middle arch second lining 7 and the front arch second lining are symmetrically and closely followed.

S5, constructing a rail top air channel and a middle plate: excavating a main body soil body to the position below the bottom surface of a preset rail top air channel along the axial direction of a middle pile 9 and a side pile 2 at the bottoms of a first pilot tunnel I, a second pilot tunnel II, a third pilot tunnel III and a fourth pilot tunnel IV, pouring a cushion layer below the rail top air channel, then pouring a lower plate 15 of the rail top air channel through a vertical mold, and reserving reinforcing steel bars of a rail top air channel side plate 14; the reinforcing bar of ligature rail top wind channel curb plate 14 and found the mould and pour rail top wind channel curb plate 14, carry out the ligature of medium plate 8 reinforcing bar afterwards, set up the perpendicular muscle of main part side wall 3 simultaneously, this perpendicular muscle upper end is connected to side longeron 4, and its lower extreme is connected to the 8 reinforcing bars of medium plate to found the mould and accomplish pouring of medium plate 8. Specifically, S5 includes the following steps:

s51, completely removing the remaining first side arch primary support 11 in the first pilot tunnel I and the fourth pilot tunnel IV;

s52, excavating soil bodies below the first pilot tunnel I, the second pilot tunnel II, the third pilot tunnel III and the fourth pilot tunnel IV by adopting segmented layering, constructing side piles 2 through inter-pile hanging nets along with the excavation of the soil bodies, and spraying concrete;

s53, when the main body soil body is integrally excavated to be close to the designed elevation of the bottom soil mold of the rail top air channel, the control of the excavation elevation is strengthened, a soil layer with the thickness of 30cm is reserved for manual bottom cleaning, and overexcavation is strictly prohibited;

s54, after excavating to a designed elevation, firstly pouring a lower plate 15 of the rail top air channel and reserving reinforcing steel bars of a side plate 14 of the rail top air channel;

s55, after the lower plate 15 is poured, supporting a support template of the vertical middle plate 8 of the lower plate 15, binding reinforcing steel bars of the rail top air channel side plate 14, and pouring the rail top air channel side plate 14 through a vertical mold;

s56, middle plate 8 and middle longitudinal beam 6 steel bar binding is carried out, the vertical ribs of the main body side wall 3 are arranged, the upper ends of the vertical ribs are connected to the side longitudinal beam 4, the lower ends of the vertical ribs are connected to the middle plate 8 steel bars, and pouring of the middle plate 8 is completed.

During construction, after the strength of the second lining is confirmed to reach 100%, the remaining primary supports in each pilot tunnel are firstly broken, in the embodiment, the main structure of the station is located in a rock stratum, and a support system at the top of the station is constructed, so that the main soil body is excavated by blasting, subsection and layering. In this embodiment, the height from the preset upper-layer pilot tunnel to the bottom surface of the middle plate 8 is 3.8m, so that the single-item propelling excavation is performed on the part of the earth-rock layer, and the blasting is performed. And (3) spraying concrete to form a support along with the timely construction of the hanging net among the side piles 2 along with the excavation, wherein in the embodiment, the hanging net is a steel bar net, the support is formed by adopting a grid steel frame and net plate type mode, the strength of the sprayed concrete is C25, and the thickness of a protective layer is 3.5 cm. Blasting excavation is forbidden within 30cm of the peripheries of the middle piles 9 and the side piles 2, and excavation is carried out by manually combining a small excavator so as to avoid damage to the middle piles 9 and the side piles 2. When the soil body is integrally excavated and is close to the designed elevation of the soil mould at the bottom of the air duct at the top of the rail, the control of the elevation of the opposite-opening excavation is strengthened, a soil layer with the thickness of 30cm is reserved for manual bottom cleaning, and the over-excavation is strictly forbidden. After the excavation is carried out to the designed elevation, the construction of the rail top air channel below the middle plate 8 is firstly carried out, the construction of the rail top air channel is divided into two times, the lower plate 15 of the rail top air channel is independently poured, the lower plate 15 supports the support template of the middle plate 8 by means of the lower plate 15 after the completion of the lower plate 15, and the side plates 14 on two sides of the rail top air channel are constructed together with the middle plate 8. In this embodiment, a hall floor is provided above the middle plate 8, and a platform floor is provided below the middle plate 8. The structure after the construction is completed is shown in fig. 5.

S6, bottom plate construction: and excavating a soil body below the middle plate 8 along the axial direction of the middle piles 9 and the side piles 2 to the depth of a preset substrate position, then applying an anchor rod and a primary support of the main body side wall 3, applying a current ground net, laying a waterproof layer of the bottom plate 1 and pouring the bottom plate 1. Specifically, after the concrete strength of the middle plate 8 and the middle longitudinal beam 6 reaches 100%, a platform layer soil body can be excavated, and the middle plate 8 template can be detached. The method comprises the steps of adopting blasting subsection layering to excavate a soil body, dismantling a template when excavating a first layer, strictly forbidding pedestrians below before the template is not completely dismantled, commanding machinery by specially-assigned persons in an excavation process, and strictly forbidding equipment such as an excavator to collide with a laminate structure, a middle pile 9 and a side pile 2 so as to avoid damage to the laminate structure. In the embodiment, the soil body of the platform layer is excavated in two layers, grid steel frames and net sheets between piles are constructed in time along with excavation, and concrete is sprayed to complete net spraying support between piles. The soil body naturally goes down the slope and excavates layer by layer, and after the soil body is excavated to the lower part of the bottom plate 1, the structural bottom plate 1 is constructed; according to the monitoring and measuring result, the subsection of the bottom plate 1 is consistent with that of the upper structure middle plate 8 and is not larger than 36m in principle, so that the reasonability of the construction joint setting is guaranteed. The structure after the construction is completed is shown in fig. 6.

S7, main body side wall construction: the main body side wall 3 below the middle plate 8 is constructed first, and the main body side wall 3 above the middle plate 8 is constructed later. Specifically, after the strength of the concrete of the bottom plate 1 reaches 75%, the construction of the side wall 32 of the platform layer can be carried out. The side wall construction adopts the principle of symmetrical construction and simultaneous propulsion, the length of the construction sections is kept consistent with that of the section of the bottom plate 1, the construction of the station and hall layer side wall 31 is carried out after all the station layer side walls 32 are constructed, and the construction process of the station and hall layer side walls 31 is consistent with that of the station layer side walls 32 in principle. In this embodiment, the height of the side wall 31 of the station hall layer is 3.66m, the height of the side wall 32 of the station platform layer is 6.26-6.76m according to different station sections, the pouring height is completed at one time, and the formwork adopts a single-sided wall formwork system. In order to ensure the concrete pouring efficiency and the pouring quality, windows are opened at the position of 2m of the height of the template surface, so that the side wall is full of concrete.

In this embodiment, the main body side wall 3 below the middle plate 8 and the construction joint of this middle plate 8 are oblique joints, and the construction joint department adopts fine sand backfill to be closely knit. In this embodiment, the construction joint between the middle plate 8 and the platform layer side wall 32 is located 50cm below the chamfer of the middle plate 8, the construction joint is set to be an oblique joint, the construction joint is densely backfilled by fine sand, and the construction length of each section of the middle plate 8 is not more than 36 m. Construction of the station deck 10 and other structures then takes place, the completed structure being shown in figure 7.

In summary, the construction sequence of the station main body in this embodiment is: pilot tunnel construction, middle pile and side pile construction, side longitudinal beam construction, middle arch and second side arch construction, middle arch and side arch second lining construction, rail top air duct and middle plate construction, bottom plate construction, main body side wall construction, station main body station board and other structure construction. In this embodiment, the main body side wall 3 is integrally divided into two parts in the vertical direction, that is, a station hall layer side wall 31 located above the middle plate 8 and a station layer side wall 32 located below the middle plate 8. The upper construction joint of the side wall 31 of the station hall layer in the vertical direction is formed between the upper construction joint and the side arch secondary lining 5 and the side longitudinal beam 4, and the lower construction joint is formed between the lower construction joint and the middle plate 8; the upper construction joint of the platform layer side wall 32 in the vertical direction is formed between the upper construction joint and the middle plate 8, and the lower construction joint is formed between the lower construction joint and the bottom plate 1. This embodiment is when implementing, does behind the side wall, carries out the side wall construction again after accomplishing medium plate 8 and bottom plate 1 construction among the station major structure promptly, and the side wall is under construction according to following the way, can guarantee the construction quality of medium plate 8 in the work progress, increases its stability, can avoid simultaneously constructing medium plate 8 and digging the last construction joint of back station room layer side wall 31 with the soil body of medium plate 8 below by the tension fracture to the waterproof performance at station has been guaranteed. The specific action mechanism is as follows:

when the construction of the middle plate 8 is carried out, the soil body below the middle plate 8 provides vertical support for the middle plate, the fixing point of the middle plate 8 in the vertical direction is at the connecting position of the middle plate and the middle pile 9, the end part of the side pile 2 forms a cantilever structure, and because the soil body below the middle plate 8 is not dug, the cantilever structure at this point does not, due to the support below, have an influence on the structural stability of the central plate 8, which, in the present solution, when the middle plate 8 is constructed, the vertical ribs of the side walls 31 of the station hall layer are simultaneously constructed, the middle plate 8 is connected with the side arch secondary lining 5 and the side longitudinal beam 4 in the vertical direction by the vertical ribs, i.e. the cantilever structure formed by the end of the centring plate 8 adjacent to the side piles 2, provides an upward pulling force in the vertical direction, so that when the soil support below it is removed, this cantilever structure atress is good in vertical direction to improve and support the structural stability who gets rid of back medium plate 8 below medium plate 8. Along with the progress of construction, the excavation of platform layer space is accomplished, medium plate 8 at this moment is in the unsettled state, main part side wall 3 is under construction with the mode of doing in the same direction after bottom plate 1 construction is accomplished, construction station platform layer side wall 32 earlier is under construction station room layer side wall 31 promptly, it is specific, after platform layer side wall 32 construction is accomplished, it can provide vertical ascending holding power to the tip that board 8 is close to side pile 2, form the support with the common centering plate 8 of the perpendicular muscle of station room layer side wall 31 and fix, the position stability of medium plate 8 in the axial of well stake 9 and side pile 2 has been guaranteed. Construction is carried out to standing room layer side wall 31 afterwards, because the position stability of medium plate 8 in the axial of well stake 9 and side pile 2, its position change or deformation can not appear in vertical direction under the effect of its gravity promptly to avoided the construction joint to be pulled apart on the standing room layer side wall 31 when providing the support to standing room layer side wall 31, guaranteed the waterproof performance of station.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.