Pile support integrated construction method for station-tunnel combined construction wide and large foundation pit

Abstract

The invention discloses a station-tunnel combined construction wide foundation pit pile support integrated construction method which comprises the following steps: firstly, piling station fender posts and tunnel fender posts before excavating a foundation pit, and secondly, constructing station crown beams, adjacent tunnel crown beams, tunnel support beams and haunch concrete slabs. And thirdly, an opposite-vertex supporting structure is erected in a rectangle defined by the station fender posts. And fourthly, earthwork in the station foundation pit is excavated, earthwork in the tunnel is excavated synchronously, and a large communicating foundation pit for communicating the tunnel foundation pit with the station foundation pit is formed. And fifthly, a station main body structure and a tunnel main body structure are constructed. According to the construction method, the previous method that the station structure is constructed firstly and then the tunnel structure is constructed is changed into the method that the station structure and the adjacent tunnel structure are constructed synchronously, and therefore the adjacent tunnel fender posts can provide pulling force for the station fender posts through anchoring force formed when the adjacent tunnel fender posts are inserted into the soil body. After the construction and dismantling of the longitudinal opposite top supporting beam are cancelled, the movable space of construction machinery is widened, and the effects of reducing cost and increasing efficiency are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and in particular to the construction technology of subway stations and subway tunnels. Background Art

[0002] With the development of society, subways have gradually become the main force of public transportation in medium and large cities. In the increasingly dense network, subway stations with multiple lines and multiple parallel lines are becoming more and more common. The subway station is connected to the front and rear section tunnels, and the wide subway station deep foundation pit is connected to the section tunnel foundation pit. The support of the foundation pit has become a difficult problem encountered in the project.

[0003] Figure 1 The left and right directions are the width directions of the station and are used as the width directions in the present invention. Figure 1 The up and down direction is the extension direction of the subway tunnel, which is also the length direction of the station and serves as the length direction in the present invention.

[0004] For such problems, Figure 1 As shown in the figure, the conventional support scheme is to excavate the station foundation pit and the tunnel foundation pit separately. The station foundation pit is excavated first, and retaining piles (station retaining pile 1, blue small circle) are used around it. A crown beam is set on the top of the station retaining pile 1, and concrete support (station support beam) is used inside. Since the foundation pit is too wide, a central column 3 (with cross lines in the purple circle) must be set at a certain interval in the middle to reduce the span of the station support beam. After the main structure of the station is constructed, the tunnel foundation pit is excavated and the tunnel structure is constructed.

[0005] Figure 1 In the figure, the rectangular structure represented by the red dotted line is the outline of the station structure 4, and the rectangular structure surrounded by the station retaining piles 1 is the station retaining structure.

[0006] The station foundation pit is relatively wide, with a width of up to 150 meters or even longer, and a length of up to hundreds of meters. The station retaining piles 1 around the station foundation pit are subject to pressure from the surrounding soil, and there is a danger of being pressed down into the station foundation pit. Therefore, it is necessary to use station support beams in the station foundation pit to support the station retaining piles 1. Specifically, station support beams are respectively arranged in the width direction and length direction of the rectangular structure surrounded by the station retaining piles 1. The station support beams in the width direction press the station retaining piles 1 on both sides of the width direction, and the station support beams in the length direction press the crown beams (i.e., station crown beams) of the station retaining piles 1 on both sides of the length direction. The centripetal soil pressures on the station retaining piles 1 in the length and width directions are offset by the station support beams and the station crown beams, thereby preventing the station retaining piles 1 from tilting centripetally (inwardly) and collapsing.

[0007] Figure 1The middle cyan part is the station support beam in the station foundation pit, which is used to prevent the retaining piles from tilting under soil pressure and protect the construction environment in the foundation pit (the main structure of the construction station).

[0008] Figure 1 The area enclosed in medium blue is the constructed area, i.e. the station structure 4 and its enclosure area; Figure 1 The middle gray area is the current construction area, which is also the area of ​​the tunnel structure and its enclosure structure. In the prior art, the tunnel structure is constructed after the station structure is completed.

[0009] like Figure 1 As shown, the station support beam ( Figure 1 The middle cyan part) includes a transverse top support beam 2 extending along the width direction of the station, a longitudinal top support beam 5 extending along the length direction of the station, and an inclined top support beam 6; the inclined top support beam 6 is set at the corner of the station construction area, the end of the transverse top support beam 2 and the station crown beams on both sides of the width direction, and the end of the longitudinal top support beam 5 and the station crown beams of the station retaining piles 1 on both sides of the length direction. The transverse top support beam 2 and the longitudinal top support beam 5 form a cross support beam structure.

[0010] Both ends of these station support beams are connected to the station crown beams on the top of the station retaining piles 1. Since these station support beams have a large span, it is necessary to set a number of station center columns 3 at intervals below ( Figure 1 The purple circles are the station's central pillars 3. Figure 1 The purple circles are marked with cross lines) to support the station support beams. Figure 1 As shown, in the prior art, the central column 3 of the station in the cross-support beam structure divides the internal space of the station structure 4, so that the construction machinery is severely restricted by these structures in the station space. The movement and operation of the construction machinery need to avoid these structures, which causes great trouble to the construction and limits the construction efficiency.

[0011] Since the station structure 4 is constructed first and then the tunnel structure, the rectangle enclosed by the station retaining piles 1 must be a continuous rectangle and cannot be interrupted at the tunnel.

[0012] In summary, the existing subway tunnel construction technology is to construct the station structure 4 first, and then construct the tunnel structure. It is also necessary to set up station retaining piles 1 (retaining piles of the station foundation pit) at the junction of the station structure 4 and the tunnel structure. This part of the station retaining piles 1 must be removed after construction to avoid affecting the connectivity between the tunnel structure and the station structure. In order to prevent the station retaining piles 1 from tilting or even overturning under soil pressure, it is necessary to set up criss-crossing station support beams and corresponding multiple station center columns 3 in the station retaining structure, which divides the space in the station structure 4, limits the construction machinery and construction efficiency, and the longer (more) station support beams and center columns 3 are only temporary construction structures, which need to be removed after the construction is completed. The more these structures are, the higher the construction cost will be. If these structures can be reduced, not only can the cost be reduced, but also the overall construction efficiency can be improved (the time for constructing these structures is reduced, and there are fewer obstacles to the construction machinery, which improves the efficiency of constructing the station structure 4).

[0013] There are two main categories of applicants' design ideas.

[0014] The first type of design idea is to coordinate construction and improve construction sequence with the goal of reducing costs and increasing efficiency. Through the improvement of construction procedures and construction organization, the traditional station and tunnel foundation pit step-by-step construction is adjusted to the simultaneous construction of station and tunnel. The tunnel retaining structure can be used to replace part of the station support beams, reducing the station support beams and the station neutral columns supporting the station support beams.

[0015] The second type of design idea is to reduce costs and increase efficiency. The design can use the tunnel retaining structure to replace part of the station support beams and the construction structure of the station center column 3, and change the traditional support form inside the foundation pit to the anchor form outside the foundation pit (reducing the support structure inside the foundation pit).

[0016] The present invention aims to protect the method-based technical solutions generated by the above-mentioned first type of design ideas. Summary of the invention

[0017] The purpose of the present invention is to provide an integrated construction method for pile support of a wide foundation pit for the combined construction of a station and a tunnel. By improving the construction process and construction organization, the tunnel retaining structure is used to replace the function of a part of the station support beams, the number of station support beams and station central columns is reduced, and cost reduction and efficiency improvement are achieved.

[0018] To achieve the above-mentioned purpose, the station-tunnel combined wide foundation pit pile-support integrated construction method of the present invention adopts a station-tunnel combined wide foundation pit pile-support integrated support structure, and the station-tunnel combined wide foundation pit pile-support integrated support structure is used to coordinate the construction of the station enclosure structure and the tunnel enclosure structure adjacent to the station enclosure structure; The extension direction of the tunnel is the length direction of the station, and the direction perpendicular to the length direction in the horizontal plane is the width direction of the station; The station enclosure structure includes a plurality of station enclosure piles surrounding the station structure; the station enclosure piles are arranged as a whole in a rectangle, and the rectangle enclosed by the station enclosure piles is called the enclosure pile rectangle; the station enclosure structure is used to form a space for constructing the station structure inside it; the tunnel enclosure structure includes tunnel enclosure piles arranged on both sides of the tunnel, The tunnel retaining piles that are less than X meters away from the station retaining piles are called adjacent tunnel retaining piles; X is a real number and 30≤X≤50; The top of the adjacent tunnel retaining pile is provided with an adjacent tunnel crown beam, and the top of the station retaining pile is provided with a station crown beam. The intersection of the station crown beam and the adjacent tunnel crown beam forms an axilla area, and an axilla concrete slab is cast at the axilla area. The axilla concrete slab connects the station crown beam and the adjacent tunnel crown beam and serves as an anchor for the station retaining pile; A transverse top-supporting beam is arranged in the rectangular area surrounded by the station retaining piles along the width direction of the station, and the two ends of the transverse top-supporting beam are respectively connected to the station crown beams on both sides thereof; a number of station central columns are arranged at intervals below the transverse top-supporting beam, and the transverse top-supporting beam forms a straight-line supporting beam structure, and the station central columns of the straight-line supporting beam structure divide the internal space of the station structure; The rectangular retaining piles at the intersection with the tunnel are set as an open structure; inclined top support beams are provided at the four corners of the rectangular retaining piles; inclined top support beams are provided between the transverse top support beams and the station crown beams on the left and right sides; the tunnel is a bidirectional tunnel, and the adjacent tunnel crown beams of the two tunnels and the station crown beams between the two tunnels are connected with inter-tunnel support beams, and the inter-tunnel support beam structure is used to generate tension on the station crown beams between the two tunnels in the length direction and prevent the station retaining piles from tilting inwards under the action of soil pressure; The process is as follows: The first step is to construct station retaining piles and tunnel retaining piles from the unexcavated ground; The second step is to construct the station crown beam on the top of the station retaining pile after excavating the ground to the crown beam bottom elevation, and construct the adjacent tunnel crown beam on the top of the adjacent tunnel retaining pile, anchor the steel bars in the station retaining pile into the station crown beam, and anchor the steel bars in the adjacent tunnel retaining pile into the adjacent tunnel crown beam; anchor the steel bars in the station crown beam and the steel bars in the adjacent tunnel crown beam to each other to form an integral structure, and construct a tunnel support beam between two adjacent tunnel crown beams in the same tunnel; construct an axil angle concrete slab at the corner where the adjacent tunnel crown beam and the station crown beam meet; The length of the adjacent tunnel retaining piles and the adjacent tunnel cap beams is 30-50 meters to ensure that the adjacent tunnel retaining piles can withstand the soil pressure exerted by the soil on the station retaining piles in the length direction. The third step is to erect a top support structure inside the rectangle surrounded by the station retaining piles, including the transverse top support beam, the inclined top support beam and the corresponding station center column; The fourth step is to excavate the earth in the station foundation pit in the area surrounded by the station retaining piles, and simultaneously excavate the earth in the tunnel in the tunnel retaining piles to form a large interconnecting foundation pit connecting the tunnel foundation pit and the station foundation pit; the large interconnecting foundation pit is excavated to the base elevation.

[0019] The fifth step is to construct the main structure of the station and the main structure of the tunnel. After the main structure of the station and the main structure of the tunnel are capped, the transverse top support beams, inclined top support beams and all the central columns of the station are removed.

[0020] In the second step, inter-tunnel support beams made of concrete are constructed between the cap beams of adjacent tunnels of two parallel tunnels and the cap beam of a station between the two tunnels.

[0021] The present invention has the following advantages: The construction method of the present invention changes the previous method of constructing the station structure first and then the tunnel structure to a method of constructing the station structure and the adjacent tunnel structure (the distance from the station retaining piles is less than X meters) simultaneously, so that the adjacent tunnel retaining piles can use the anchoring force formed by their insertion into the soil to provide a pulling force in the length direction of the station to the station retaining piles. This pulling force is in the same direction as the supporting force of the longitudinal top support beam 5 on the station retaining piles in the prior art. The regulation of X meters is to enable this pulling force to completely replace the supporting force of the longitudinal top support beam 5 on the station retaining piles in the prior art.

[0022] Through the station crown beam, the axil concrete slab and the adjacent tunnel crown beam, the present invention utilizes the adjacent tunnel retaining piles within 30-50 meters of the station retaining piles to generate tension on the station crown beam, constraining the station retaining piles on both sides of the length direction from tilting inwards under the action of the surrounding soil pressure, thereby eliminating the existing technology ( Figure 1 ) in the longitudinal top support beam 5, the previous cross support beam structure is improved into a straight support beam structure, thereby achieving the following technical effects: ① Save additional Figure 1 The material cost of the middle longitudinal top support beam 5 and the inclined top support beam 6 connected to the longitudinal top support beam 5.

[0023] ② The construction efficiency of the armpit concrete slab is higher than that of the longitudinal top support beam 5 and the inclined top support beam 6 connected to the longitudinal top support beam 5, thereby improving the construction efficiency of the enclosure support structure.

[0024] ③ After the longitudinal top support beam 5 is cancelled, the multiple station neutral columns connected downward by the longitudinal top support beam 5 are naturally cancelled. These cancelled station neutral columns no longer participate in dividing the internal space of the station structure, and no longer constitute a spatial restriction on the construction machinery of the station structure, so that the construction machinery can move and carry out construction activities more flexibly within the space surrounded by the station enclosure structure. Since a large number of station neutral columns that restrict the movement of construction machinery have been reduced, a wider construction space is provided for the construction machinery of the station structure compared with the past, which greatly improves the efficiency of the construction machinery in constructing the station structure.

[0025] ④ The station's central column and longitudinal top-supporting beams are structures that need to be dismantled after construction. The present invention eliminates the longitudinal top-supporting beams and multiple station central columns connected thereto, and there is no need to dismantle these structures, thereby improving construction efficiency and greatly reducing construction waste generated after dismantling all supporting beams and central columns, greatly reducing the cost required to handle these construction wastes, and greatly reducing the environmental hazards caused by these construction wastes.

[0026] By adopting the structure of the present invention, no station retaining pile (opening structure) is provided at the end of the tunnel, which has the following technical effects: ① Save the material cost required for setting up the station retaining piles.

[0027] ② After the station structure and tunnel structure are constructed, it is no longer necessary to remove the station retaining piles to connect the tunnel and the station. Since there is no need to construct or remove the station retaining piles, the construction efficiency is improved and the environmental damage caused by the construction waste caused by the removal of the station retaining piles is avoided.

[0028] The tunnel support beam plays a strong role in tying and limiting the station retaining piles outside the axilla concrete slabs, and together with the axilla concrete slabs, bears the earth pressure on the station retaining piles in the length direction (up and down direction) after the longitudinal top support beam 5 is cancelled.

[0029] In the present invention, the tunnel crown beam and the station crown beam are connected as a whole, and the corners are provided with reinforced axilla corners (axilla corner concrete slabs). The tunnel retaining piles and the adjacent tunnel crown beams are connected as a whole to serve as the supporting structure of the tunnel foundation pit, and at the same time, they also serve as the anchor support outside the station retaining pile foundation pit, realizing the integrated support structure of the station-tunnel combined pile support, greatly reducing the station support and central column in the station foundation pit, with large construction space, high construction efficiency and low engineering costs.

[0030] By adopting the construction method of the present invention, structures such as station retaining piles, station crown beams, adjacent tunnel retaining piles, adjacent tunnel crown beams, and reinforced axillae (axillae concrete slabs) can be constructed simultaneously, and the station foundation pit and part of the tunnel foundation pit (referring to the part adjacent to the station foundation pit, that is, the tunnel foundation pit within X meters from the station foundation pit) can be excavated simultaneously, and the station and the tunnel are built together, avoiding the disadvantages of traditional step-by-step construction, such as long construction period, large number of retaining piles, inability to use adjacent tunnel retaining piles to provide anchoring force to the station retaining piles, and the need to construct longitudinal top support beams.

[0031] The construction method of the present invention changes the previous method of constructing the station structure first and then the tunnel structure to a method of constructing the station structure and the adjacent tunnel structure (the distance from the station retaining piles is less than X meters) simultaneously, so that the adjacent tunnel retaining piles can use the anchoring force formed by their insertion into the soil to provide a pulling force in the length direction of the station to the station retaining piles. This pulling force is in the same direction as the supporting force of the longitudinal top support beam 5 on the station retaining piles in the prior art. The regulation of X meters is to enable this pulling force to completely replace the supporting force of the longitudinal top support beam 5 on the station retaining piles in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a supporting and retaining structure for station foundation pit and tunnel foundation pit in the prior art. Figure 1 The area enclosed in medium blue is the area that has been constructed, and the gray area is the area currently under construction.

[0033] Figure 2 It is the supporting and retaining structure of the station foundation pit and the tunnel foundation pit in the present invention. The part of the tunnel retaining piles framed by the gray rectangle (i.e. the adjacent tunnel cap beam) is the adjacent tunnel retaining piles.

[0034] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0035] Figure 4 yes Figure 2 AA section view.

[0036] Figure 5 yes Figure 2 BB cross-sectional view.

[0037] Figure 6 yes Figure 2 CC cross-sectional view. DETAILED DESCRIPTION

[0038] The present invention provides a station-tunnel combined construction method for a wide foundation pit with pile support. To implement the construction method, the present invention also provides Figures 2 to 6 (and refer to Figure 1) is used to coordinate the construction of the station retaining structure and the tunnel retaining structure adjacent to the station retaining structure; The extension direction of the tunnel is the length direction of the station, and the direction perpendicular to the length direction in the horizontal plane is the width direction of the station (i.e. Figure 1 and Figure 2 left and right directions in ); The station enclosure structure includes the station structure 4 (in the vicinity of Figure 1 -6) of multiple station retaining piles 1 ( Figures 1 to 6 The station retaining piles 1 are arranged as a whole in a rectangle, and the rectangle formed by the station retaining piles 1 is called a retaining pile rectangle; the station retaining structure is used to form a space for constructing the station structure 4 inside it; The tunnel retaining structure includes tunnel retaining piles 7 arranged on both sides of the tunnel; The tunnel retaining pile 7 whose distance from the station retaining pile 1 is less than X meters is called the adjacent tunnel retaining pile 9 (i.e. Figure 2 and Figure 3 The tunnel retaining piles in the green rectangle 7); X is a real number and 30≤X≤50; An adjacent tunnel cap beam 10 is provided on the top of the adjacent tunnel retaining pile 9, and a station cap beam 11 is provided on the top of the station retaining pile 1. An armpit portion is formed at the intersection of the station cap beam 11 and the adjacent tunnel cap beam 10. An armpit portion is cast with an armpit concrete slab 12. The armpit concrete slab 12 connects the station cap beam 11 and the adjacent tunnel cap beam 10 and is used to anchor the station retaining pile 1. The anchoring effect refers to providing a pulling force to resist soil pressure (force in the length direction of the station) on the station retaining pile 1. A transverse top-supporting beam 13 is arranged in the rectangular area surrounded by the station retaining piles 1 along the width direction of the station, and the two ends of the transverse top-supporting beam 13 are respectively connected to the station crown beams 11 on both sides thereof; a plurality of station center columns 14 are arranged at intervals downwardly of the transverse top-supporting beam 13 (when the span of the top-supporting beam is large, the station center column 14 is arranged to support the top-supporting beam, and the length of the top-supporting beam between adjacent station center columns 14 is 8-12 meters, including the values ​​at both ends), and the station center column 14 is arranged at intervals downwardly of the transverse top-supporting beam 13. Figures 1 to 3 The neutral columns in the figure are for reference only and not all neutral columns are shown.

[0039] The transverse top support beams 13 form a straight-line support beam structure, and the central columns 14 of each station of the straight-line support beam structure divide the internal space of the station structure 4.

[0040] Through the station crown beam 11, the axil concrete slab 12 and the adjacent tunnel crown beam 10, the present invention utilizes the adjacent tunnel retaining piles 9 within 30-50 meters of the station retaining piles 1 to generate tension on the station crown beam 11, constraining the station retaining piles 1 on both sides of the length direction from tilting inwards under the action of the surrounding soil pressure, thereby eliminating the prior art ( Figure 1 ) in the longitudinal top support beam 5, the previous cross support beam structure is improved into a straight support beam structure, thereby achieving the following technical effects: ① Save additional Figure 1 The material cost of the middle longitudinal top support beam 5 and the inclined top support beam 6 connected to the longitudinal top support beam 5.

[0041] ② The construction efficiency of the armpit concrete slab 12 is higher than that of the longitudinal top support beam 5 and the inclined top support beam 6 connected to the longitudinal top support beam 5, thereby improving the construction efficiency of the enclosure support structure.

[0042] ③ After the longitudinal top support beam 5 is cancelled, the multiple station center columns 14 connected downward by the longitudinal top support beam 5 are naturally cancelled. These cancelled station center columns 14 no longer participate in dividing the internal space of the station structure 4, and no longer constitute a space restriction on the construction machinery of the station structure 4, so that the construction machinery can move and carry out construction activities more flexibly within the space surrounded by the station enclosure structure. Since a large number of station center columns 14 that restrict the movement of construction machinery are reduced, a wider construction space is provided for the construction machinery of the station structure 4 compared with the past, which greatly improves the efficiency of the construction machinery in constructing the station structure.

[0043] ④ The station center column 14 and the longitudinal top support beams are structures that need to be dismantled after construction. The present invention eliminates the longitudinal top support beams and the multiple station center columns 14 connected thereto, and there is no need to dismantle these structures, thereby improving construction efficiency and greatly reducing the construction waste generated after the dismantling of all support beams and center columns, greatly reducing the cost required to handle these construction wastes, and greatly reducing the environmental hazards caused by these construction wastes.

[0044] The rectangular retaining piles at the intersection with the tunnel are set as an open structure 15, that is, the station retaining piles 1 are not set at the end of the tunnel. Compared with the prior art, the station retaining piles 1 at the end of the tunnel are eliminated.

[0045] By adopting the structure of the present invention, the station retaining pile 1 (opening structure 15) is not provided at the end of the tunnel, which has the following technical effects: ① Save the material cost required for setting up the station retaining piles 1.

[0046] ② After the station structure 4 and the tunnel structure 18 are constructed, it is no longer necessary to remove the station retaining piles 1 to connect the tunnel and the station. Since it is not necessary to construct or remove the station retaining piles 1, the construction efficiency is improved and the environmental damage caused by the construction waste caused by the removal of the station retaining piles 1 is avoided.

[0047] An inclined top support beam 16 is provided at the four corners of the rectangular retaining pile; an inclined top support beam 16 is provided between the transverse top support beam 13 and the station crown beams 11 on its left and right sides; Among the inclined top support beams 16, the inclined top support beams 16 with a length longer than 20 meters are provided with a plurality of station center columns 14 at intervals downward (when the span of the top support beam is large, the station center columns 14 are provided to support the top support beam).

[0048] Compared with the prior art, the inclined top support beams 16 in the present invention are only provided on the left and right sides (both sides in the width direction) of the rectangular retaining pile, and there are no inclined top support beams 16 on the upper and lower sides (both sides in the length direction). The inclined top support beams 16 can enhance the overall support strength and prevent the station retaining pile 1 from partially tilting toward the center.

[0049] The tunnel is a bidirectional tunnel, and an inter-tunnel support beam 17 is connected between the adjacent tunnel crown beams 10 of the two tunnels and the station crown beam 11 between the two tunnels. The inter-tunnel support beam 17 structure is used to generate tension on the station crown beam 11 between the two tunnels in the length direction and prevent the station retaining pile 1 from tilting inward under the action of soil pressure.

[0050] The tunnel support beam 17 plays a strong role in tying and limiting the station retaining pile 1 outside the axilla concrete slab 12, and together with the axilla concrete slab 12, it bears the earth pressure on the station retaining pile 1 in the length direction (up and down direction) after the longitudinal top support beam 5 is cancelled.

[0051] The integrated construction method of pile support for a wide foundation pit for station-tunnel combined construction of the present invention is carried out in the following steps: The first step is to construct station retaining piles 1 and tunnel retaining piles 7 from the unexcavated ground (i.e., piling); The second step is to construct a station crown beam 11 on the top of the station retaining pile 1 after excavating the ground to the crown beam bottom elevation, and construct an adjacent tunnel crown beam 10 on the top of the adjacent tunnel retaining pile 9, anchor the steel bars in the station retaining pile 1 into the station crown beam 11, and anchor the steel bars in the adjacent tunnel retaining pile 9 into the adjacent tunnel crown beam 10; construct a tunnel support beam 8 between two adjacent tunnel crown beams 10 in the same tunnel, and anchor the steel bars in the station crown beam 11 and the steel bars in the adjacent tunnel crown beam 10 to form an integral structure; Concrete slabs 12 are constructed at the corners where the adjacent tunnel crown beams 10 and station crown beams 11 meet; The length of the adjacent tunnel retaining piles 9 and the adjacent tunnel cap beams 10 is 30-50 meters (including both ends) to ensure that the adjacent tunnel retaining piles 9 as a whole can withstand the earth pressure exerted by the soil on the station retaining piles 1 in the length direction (thereby forming sufficient anchoring force on the station cap beams 11); The third step is to erect a top support structure inside the rectangle surrounded by the station retaining piles 1, including the transverse top support beam 13, the inclined top support beam 16 and the corresponding station center column 14; The fourth step is to excavate the earth in the station foundation pit in the area surrounded by the station retaining piles 1, and simultaneously excavate the earth in the tunnel in the tunnel retaining piles 7 to form a large interconnecting foundation pit connecting the tunnel foundation pit and the station foundation pit; the interconnecting large foundation pit is excavated to the base elevation.

[0052] The fifth step is to construct the main structure of the station and the main structure of the tunnel. After the main structure of the station and the main structure of the tunnel are capped, the transverse top support beams 13, the inclined top support beams 16 and all the central columns 14 of the station are removed.

[0053] The construction method of the present invention changes the previous method of first constructing the station structure 4 and then constructing the tunnel structure 18 to the simultaneous construction of the station structure 4 and the adjacent tunnel structure (the distance from the station retaining pile 1 is less than X meters), so that the adjacent tunnel retaining pile 9 can use the anchoring force formed by its insertion into the soil to provide a pulling force in the length direction of the station to the station retaining pile 1. This pulling force is in the same direction as the supporting force of the longitudinal top support beam 5 on the station retaining pile 1 in the prior art. The regulation of X meters is to enable this pulling force to completely replace the supporting force of the longitudinal top support beam 5 on the station retaining pile 1 in the prior art.

[0054] In the second step, inter-tunnel support beams 17 made of concrete are constructed between adjacent tunnel cap beams 10 of two parallel tunnels and between the station cap beam 11 between the two tunnels.

[0055] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The integrated construction method of large foundation pit pile support for station-tunnel combined construction adopts the integrated support structure of large foundation pit pile support for station-tunnel combined construction, which is characterized by: The integrated support structure of the wide foundation pit pile support of the station-tunnel joint construction is used to coordinate the construction of the station retaining structure and the tunnel retaining structure adjacent to the station retaining structure; The extension direction of the tunnel is the length direction of the station, and the direction perpendicular to the length direction in the horizontal plane is the width direction of the station; The station enclosure structure includes a plurality of station enclosure piles surrounding the station structure; the station enclosure piles are arranged as a whole in a rectangle, and the rectangle enclosed by the station enclosure piles is called the enclosure pile rectangle; the station enclosure structure is used to form a space for constructing the station structure inside it; the tunnel enclosure structure includes tunnel enclosure piles arranged on both sides of the tunnel, The tunnel retaining piles that are less than X meters away from the station retaining piles are called adjacent tunnel retaining piles; X is a real number and 30≤X≤50; The top of the adjacent tunnel retaining pile is provided with an adjacent tunnel crown beam, and the top of the station retaining pile is provided with a station crown beam. The intersection of the station crown beam and the adjacent tunnel crown beam forms an axilla area, and an axilla concrete slab is cast at the axilla area. The axilla concrete slab connects the station crown beam and the adjacent tunnel crown beam and serves as an anchor for the station retaining pile; A transverse top-supporting beam is arranged in the rectangular area surrounded by the station retaining piles along the width direction of the station, and the two ends of the transverse top-supporting beam are respectively connected to the station crown beams on both sides thereof; a number of station central columns are arranged at intervals below the transverse top-supporting beam, and the transverse top-supporting beam forms a straight-line supporting beam structure, and the station central columns of the straight-line supporting beam structure divide the internal space of the station structure; The rectangular retaining piles at the intersection with the tunnel are set as an open structure; inclined top support beams are provided at the four corners of the rectangular retaining piles; inclined top support beams are provided between the transverse top support beams and the station crown beams on the left and right sides; the tunnel is a bidirectional tunnel, and the adjacent tunnel crown beams of the two tunnels and the station crown beams between the two tunnels are connected with inter-tunnel support beams, and the inter-tunnel support beam structure is used to generate tension on the station crown beams between the two tunnels in the length direction and prevent the station retaining piles from tilting inwards under the action of soil pressure; The process is as follows: The first step is to construct station retaining piles and tunnel retaining piles from the unexcavated ground; The second step is to construct the station crown beam on the top of the station retaining pile after excavating the ground to the crown beam bottom elevation, and construct the adjacent tunnel crown beam on the top of the adjacent tunnel retaining pile, anchor the steel bars in the station retaining pile into the station crown beam, and anchor the steel bars in the adjacent tunnel retaining pile into the adjacent tunnel crown beam; anchor the steel bars in the station crown beam and the steel bars in the adjacent tunnel crown beam to each other to form an integral structure, and construct a tunnel support beam between two adjacent tunnel crown beams in the same tunnel; construct an axil angle concrete slab at the corner where the adjacent tunnel crown beam and the station crown beam meet; The length of the adjacent tunnel retaining piles and the adjacent tunnel cap beams is 30-50 meters to ensure that the adjacent tunnel retaining piles can withstand the soil pressure exerted by the soil on the station retaining piles in the length direction. The third step is to erect a top support structure inside the rectangle surrounded by the station retaining piles, including the transverse top support beam, the inclined top support beam and the corresponding station center column; The fourth step is to excavate the earthwork in the station foundation pit in the area surrounded by the station retaining piles, and simultaneously excavate the earthwork in the tunnel in the tunnel retaining piles to form a large interconnecting foundation pit connecting the tunnel foundation pit and the station foundation pit; the interconnecting large foundation pit is excavated to the base elevation; The fifth step is to construct the main structure of the station and the main structure of the tunnel. After the main structure of the station and the main structure of the tunnel are capped, the transverse top support beams, inclined top support beams and all the central columns of the station are removed.

2. The construction method according to claim 1, characterized in that: In the second step, inter-tunnel support beams made of concrete are constructed between the cap beams of adjacent tunnels of two parallel tunnels and the cap beam of a station between the two tunnels.

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