Construction method for protecting transfer channel of comprehensive transportation hub when meeting box culvert

Abstract

The invention discloses a comprehensive transportation hub transfer channel box culvert protection construction method which comprises the steps of transfer channel second-stage foundation pit supporting construction, transfer channel second-stage foundation pit bottom sand layer reinforcement and reinforcement of soil bodies on the two sides below a drainage box culvert, drainage box culvert protection construction and earth excavation. The method comprises the following steps: first-stage construction of a transfer channel, second-stage construction of the transfer channel, enclosure construction of first-stage and second-stage interfaces of the transfer channel, digging construction of the first-stage and second-stage interfaces of the transfer channel, construction of the first-stage and second-stage interfaces of the transfer channel, and penetration of the transfer channel. According to the construction method, a transfer channel second-stage foundation pit bottom sand layer and soil bodies on the two sides below a drainage box culvert are reinforced, a suspension rod is arranged on a first concrete foundation pit horizontal inner support, the drainage box culvert is protected through the suspension rod, protection channel steel is transversely arranged on a second concrete foundation pit horizontal inner support, the protection channel steel penetrates through the bottom of the drainage box culvert, and the drainage box culvert is protected through the protection channel steel. The protection channel steel is arranged to support the drainage box culvert, it can be guaranteed that the earth does not sink during excavation, and the problem that the sand layer geology of the second-stage foundation pit of the transfer channel is difficult to reinforce is solved through the construction method.

Description

Technical Field

[0001] The invention relates to the technical field of transfer construction at a transportation hub, and in particular to a construction method for protecting a transfer passage at a comprehensive transportation hub against a box culvert. Background Art

[0002] As the scale of subway construction continues to expand, subway stations will encounter various municipal pipelines and underground obstacles during the construction process. For example, during the construction of transfer passages at transportation hubs, box culverts will be encountered. The existing construction method of the transfer channel is usually as follows: the transfer channel is constructed in three phases. When the construction workers drill holes and grouting from the first phase of the transfer channel, water and sand will gush out, making it impossible to perform grouting and affecting the construction of the first phase. The interface between the second phase of the transfer channel foundation pit and the main body of the station adopts an open excavation method. The excavation depth of the second phase of the transfer channel foundation pit is about 10m, and the base is mainly located in the gravel and sand layer. The construction of the second phase of the transfer channel foundation pit retaining structure usually adopts the "bored pile + internal support" method. Since there is a rectangular rainwater culvert about 0.7m below the ground of the second phase of the transfer channel foundation pit, the rainwater culvert crosses the second phase of the transfer channel foundation pit, and bored cast-in-place pile construction cannot be performed, affecting the construction of the second phase of the transfer channel retaining structure. During the operation of the subway station, these culverts cannot be interrupted, especially some rainwater culverts involved in flood control and drainage, and the flow cannot be interrupted. Therefore, it is urgent to provide a construction method that can solve the problem that the foundation pit of the transfer channel in the transportation hub crosses the rainwater culvert and the bottom of the foundation pit is a sand layer. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a construction method for the defects of the prior art, which adopts soil reinforcement and water stopping near bored cast-in-place piles on both sides of the drainage box culvert, connects the bored cast-in-place piles on both sides of the drainage box culvert with a concrete retaining wall on the inner side of the second phase foundation pit of the transfer channel, excavates the covering soil above the drainage box culvert before the construction of the bored cast-in-place pile foundation, accurately locates the position of the drainage box culvert and the 10KV power pipe, avoids the conflict between the bored cast-in-place piles and the underground pipelines and the drainage box culvert, and solves the problem that the sand layer of the second phase foundation pit of the transfer channel is difficult to reinforce.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A construction method for box culvert protection of a transfer channel in a comprehensive transportation hub, wherein the first phase and the second phase of the transfer channel of the comprehensive transportation hub are connected, and the construction method includes the following processes:

[0006] Step 1) Construction of support for the foundation pit of the transfer channel phase II: The drainage box culvert spans the foundation pit of the transfer channel phase II. The two sides of the foundation pit of the transfer channel phase II are adjacent to the subway station entrance and the transfer channel phase I respectively. The other two sides of the foundation pit of the transfer channel phase II are constructed with bored piles and double-tube rotary jet piles respectively. The bored piles and double-tube rotary jet piles pass through the bottom sand layer of the foundation pit of the transfer channel phase II.

[0007] Step 2) Reinforcement construction: The soil on both sides below the drainage culvert is close to the bored cast-in-place piles, and the bottom sand layer of the transfer channel phase II foundation pit and the soil on both sides below the drainage culvert are reinforced. The soil reinforcement is divided into three times. The first reinforcement: first drill vertically from the original ground, drill and grout to reinforce the bottom sand layer of the transfer channel phase II foundation pit and stabilize the base soil; the second reinforcement: drill from the direction of the adjacent transfer channel phase I, use steel flower pipes to grout the drilled holes to stabilize the soil under the drainage culvert; the third reinforcement: open holes for anchoring between the bored cast-in-place piles on both sides, drill obliquely, and use hollow anchor rods for oblique drilling and grouting;

[0008] Step 3) Drainage culvert protection construction: make a concave structure water-stop steel plate, weld angle steel U-shaped buckles on both sides of the water-stop steel plate, fix the water-stop steel plate to the side wall of the drainage culvert through the angle steel U-shaped buckles on both sides, build brick walls to seal the two ends of the drainage culvert after the water-stop steel plate is installed and fixed, and simultaneously carry out earthwork excavation on both sides of the drainage culvert, set a suspension rod on the first concrete foundation pit horizontal inner support, use the suspension rod to lift the drainage culvert to protect the drainage culvert, and horizontally place a protective channel steel on the second concrete foundation pit horizontal inner support, and the protective channel steel passes through the bottom of the drainage culvert and supports the drainage culvert;

[0009] Step 4) Continue to excavate the bottom of the drainage box culvert and construct the second phase of the transfer channel;

[0010] Step 5) Enclosure construction of the transfer channel phase I and II docking ports: The power pipeline relocation, retaining wall, and temporary enclosure structure of the transfer channel phase I and II are all constructed at night. The enclosure structure includes an enclosure foundation, an enclosure plate, and an enclosure fixing. A deep groove is formed at the upper end of the enclosure foundation, and an enclosure foot is formed at the bottom of the enclosure plate. The enclosure foot at the bottom of the enclosure plate is embedded in the deep groove and fixed by the enclosure fixing, and then the deep groove of the enclosure foundation is filled with mortar;

[0011] Step 6) Excavation and construction of the transfer channel phase I and II docking ports: demolish the side walls, and demolish the transfer channel phase I and phase II respectively;

[0012] Step 7) Construction of the transfer channel phases 1 and 2 docking points.

[0013] Step 8) The first and second phases of the transfer channel are completed.

[0014] Furthermore, in step 2), the soil on both sides below the drainage culvert is reinforced for the third time by grouting with hollow anchor rods and bored piles at both ends of the concrete retaining wall. The soil on both sides below the drainage culvert is excavated from top to bottom. After each layer is excavated, hollow anchor rods are immediately used for grouting reinforcement in a plum blossom shape. Then, the steel mesh is hung on the hollow anchor rods, and then slurry is sprayed on the steel mesh. Then, several layers of horizontal grid steel frames are installed. After several layers of horizontal grid steel frames are installed, concrete is finally sprayed to form a concrete retaining wall.

[0015] Furthermore, the bored cast-in-place piles are connected to the concrete retaining wall, the bored cast-in-place piles are chiseled open to expose the steel bars, and the exposed steel bars are connected to the steel bars of the concrete retaining wall by welding.

[0016] Furthermore, several layers of horizontal grid steel frames are placed layer by layer from the bottom of the transfer channel phase II foundation pit to the bottom of the drainage box culvert, and several layers of horizontal grid steel frames are connected into an integrated structure by longitudinal connecting ribs, and the horizontal spacing between two adjacent layers of horizontal grid steel frames is 1m.

[0017] Furthermore, each layer of horizontal grid steel frame includes four supporting main bars and a plurality of annular ring bars, the plurality of annular ring bars are evenly distributed on the four supporting main bars at longitudinal intervals, each annular ring bar surrounds the outer circumference of the four supporting main bars and is welded thereto, and the four supporting main bars are connected by a plurality of annular ring bars to form a horizontal grid steel frame.

[0018] Furthermore, in step 1), a steel ring is pre-buried in the pile body of the bored pile, and the height of the steel ring is from the bottom of the drainage box culvert to the bottom of the second phase foundation pit of the transfer channel. The steel ring is welded with several layers of vertical steel plates, and two supporting main bars of the horizontal grid steel frame are welded with vertical steel plates respectively. The steel ring of the bored pile is fixed with five steel ring anchor bars in the vertical direction, and the five steel ring anchor bars are arranged radially, and the steel ring anchor bars are anchored into the pile body of the bored pile.

[0019] Furthermore, the 10KV power pipe above the drainage culvert in step 3) is suspended and protected by a suspension structure, a suspension point is set at every 1m on the wall, and an expansion bolt is fixed at the suspension point. The suspension structure includes a sleeve, a suspension rope, and a basket bolt. The sleeve is wrapped around the outer surface of the 10KV power pipe, one end of the suspension rope is wrapped around the sleeve wrapped with the 10KV power pipe, and the other end of the suspension rope is connected to one end of the basket bolt, and the other end of the basket bolt is fixed to the suspension point through the expansion bolt.

[0020] Furthermore, in step 5), the enclosure plate includes an outer lightweight steel plate, an inner lightweight steel plate, and sound insulation cotton which are arranged in sequence from the outside to the inside, the sound insulation cotton is sandwiched between the outer lightweight steel plate and the inner lightweight steel plate, and the enclosure foundation is cast with C20 concrete.

[0021] Furthermore, in step 6), the excavation construction of the transfer channel phase I and II docking port specifically includes:

[0022] Step 61) The first phase of the transfer channel is excavated first, and the side walls of the three steel support positions are removed first, and then the temporary first vertical steel support, the second vertical steel support, and the third vertical steel support are erected;

[0023] Step 62) The remaining part of the main side wall of the transfer channel phase II is excavated. The main side wall is excavated in blocks, from top to bottom in the order of transfer channel phase I → transfer channel phase II. The excavation is carried out using a water drill + rope saw method. First, a water drill is used to drill holes in the four corners of each small block, and then the rope saw is used to cut and pull out. The block size is 1m×0.82m.

[0024] Furthermore, in step 7), the specific construction process of the interface construction of the transfer channel phase I and II includes:

[0025] Step 71) constructing hidden columns;

[0026] Step 72) constructing the first phase of the transfer channel and pouring concrete beams;

[0027] Step 73) Temporary steel supports are set under the first phase concrete beams of the transfer channel;

[0028] Step 74) dismantling the first vertical steel support, the second vertical steel support, and the third vertical steel support;

[0029] Step 75) Construct the second phase of the transfer channel and pour concrete beams.

[0030] Step 76) Remove temporary steel supports, restore original decoration, remove retaining walls and enclosure structures, waterproof the interface of the transfer channel phase II foundation pit, embed grouting conduits in the bottom plate of the transfer channel phase II foundation pit interface for grouting reinforcement to ensure that the joints are caulked to form a sealed and continuous waterproof wall.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The construction method of the present invention includes the support construction of the second phase foundation pit of the transfer channel, the reinforcement construction of the bottom sand layer of the second phase foundation pit of the transfer channel and the soil on both sides below the drainage box culvert, the protection construction of the drainage box culvert, the earth excavation, the construction of the second phase of the transfer channel, the enclosure construction of the interface between the first and second phases of the transfer channel, the excavation construction of the interface between the first and second phases of the transfer channel, the construction of the interface between the first and second phases of the transfer channel, and the connection of the transfer channel. The construction method of the present invention reinforces the bottom sand layer of the second phase foundation pit of the transfer channel and the soil on both sides below the drainage box culvert, sets a suspension rod on the first concrete foundation pit horizontal inner support, uses the suspension rod to protect the drainage box culvert, and horizontally places a protective channel steel on the second concrete foundation pit horizontal inner support. The protective channel steel passes through the bottom of the drainage box culvert. The protective channel steel is set to support the drainage box culvert, which can ensure that it does not sink during earth excavation. The construction method of the present invention can solve the problem that the sand layer of the second phase foundation pit of the transfer channel is difficult to reinforce. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of a construction method for protecting a transfer passage of a comprehensive transportation hub against a box culvert according to the present invention;

[0034] Figure 2 It is a plan layout diagram of the transfer passage of the comprehensive transportation hub of the present invention;

[0035] Figure 3 It is a plan layout diagram of the second phase enclosure reinforcement of the transfer channel of the present invention;

[0036] Figure 4 It is a plan view of the second phase foundation pit of the transfer channel of the present invention using a suspension rod to protect the drainage box culvert;

[0037] Figure 5 It is a plan layout diagram of the soil reinforcement of the second phase foundation pit of the transfer channel of the present invention;

[0038] Figure 6 The present invention Figure 5 Sectional view of 1-1;

[0039] Figure 7 It is the plan layout of the first drilling and grouting reinforcement of the present invention;

[0040] Figure 8 It is a cross-sectional view of the first drilling and grouting reinforcement of the present invention;

[0041] Fig. 9 It is a plan layout diagram of drilling from the direction of the first phase of the transfer channel immediately adjacent to the present invention;

[0042] Fig.10 It is a plan view of the drilling and grouting of the bottom of the box culvert of the present invention;

[0043] Fig.11 It is a cross-sectional view of the drilling and grouting of the bottom of the drainage box culvert of the present invention;

[0044] Fig.12 It is a large-scale drawing of the end plugging of the drainage box culvert of the present invention;

[0045] Fig.13 It is a plan view of the present invention using a suspension structure to suspend and protect the power pipe;

[0046] Fig.14 It is a plan view of the horizontal grid steel frame installed inside the foundation pit of the present invention;

[0047] Fig.15 is a relationship diagram of the connection between the horizontal grid steel frame and the horizontal grid steel frame of the present invention;

[0048] Fig.16 It is a structural schematic diagram of the horizontal grid steel frame of the present invention;

[0049] Fig.17 It is a large-scale drawing of the pre-buried steel ring of the bored pile of the present invention;

[0050] Fig.18 The present invention Fig.17 Sectional view of 2-2;

[0051] Fig.19 It is a plan view of the docking port of the first and second phases of the transfer channel of the present invention;

[0052] Fig. 20 is a cross-sectional view of the enclosure structure of the present invention;

[0053] Fig.21 It is a schematic diagram of the structure of the enclosure plate of the present invention;

[0054] Fig. 22 is a plan view of the present invention with the side wall removed;

[0055] Fig.23 It is an elevation view of the connection port locations of the first and second phases of the transfer channel of the present invention.

[0056] In the figure: transfer channel phase II foundation pit 1, bored pile 11, steel ring 111, steel plate 112, steel ring anchor 113, double-tube rotary jet pile 12, first concrete foundation pit horizontal inner support 13, second concrete foundation pit horizontal inner support 14, subway station 2, transfer channel phase I 21, subway station entrance 23, subway station passage 24, soil reinforcement 3, drilling 31, hollow anchor rod 32, concrete retaining wall 33, horizontal grid steel frame 34, support main reinforcement 341, annular ring reinforcement 342, oblique reinforcement 343, longitudinal connecting reinforcement 35, connecting steel bar 36, water stop steel plate 37, angle steel U-shaped buckle 371, steel pipe 38, masonry brick wall 39. Suspension rod 4. Protection channel steel 5. Retaining wall 6. Enclosure structure 7. Enclosure foundation 71. Deep groove 711. Enclosure plate 72. Enclosure foot 721. External lightweight steel plate 722. Internal lightweight steel plate 723. Sound insulation cotton 724. Enclosure fixings 73. Concealed column 8. First phase cast concrete beam of transfer passage 81. Temporary steel support 82. First vertical steel support 83. Second vertical steel support 84. Third vertical steel support 85. Second phase cast concrete beam of transfer passage 86. Drainage culvert 9. 10KV power pipe 10. Suspension structure 101. Lifting rope 1011. Flower basket bolt 1012. Expansion bolt 1013. Water supply pipe 102. DETAILED DESCRIPTION

[0057] The present invention is described in detail below in conjunction with the accompanying drawings, which are part of this specification and illustrate the principles of the present invention through embodiments. Other aspects, features and advantages of the present invention will become clear from the detailed description. In the drawings referred to, the same or similar parts in different figures are represented by the same reference numerals.

[0058] like Figure 1-19 As shown, the first embodiment of the present invention provides a construction method for box culvert protection of a transfer channel in a comprehensive transportation hub. The transfer channel of the comprehensive transportation hub is divided into a first-phase transfer channel 21 and a second-phase transfer channel. The first-phase transfer channel 21 is connected to the entrance and exit 23 of the subway station. The foundation pit of the first-phase transfer channel 21 is 7.8m to 33.6m wide and 10.74m deep. The base is mainly located in a medium-coarse sand layer. The construction method includes the following processes:

[0059] Step 1) Support construction of the transfer channel phase II foundation pit 1: The transfer channel phase II foundation pit 1 is rectangular, and the transfer channel phase II foundation pit 1 and the station main body interface 21 are open-cut. There is a north-south drainage box culvert 9 in the transfer channel phase II foundation pit 1, and the drainage box culvert 9 spans the transfer channel phase II foundation pit 1. The two sides of the transfer channel phase II foundation pit 1 are respectively adjacent to the subway station channel entrance 24 and the transfer channel phase I 21. After the transfer channel phase I 21 foundation pit support completes the underground continuous wall construction, the other two sides of the transfer channel phase II foundation pit 1 are constructed with bored cast-in-place piles 11 and double-tube rotary jet piles 12, respectively, and the bored cast-in-place piles 11 and double-tube rotary jet piles 12 pass through the bottom sand layer of the transfer channel phase II foundation pit 1; in specific implementation, the drainage box culvert 9 is box-type concrete, and the outer diameter of the drainage box culvert 9 is 3.1 m×2.6m, the bottom elevation of the drainage culvert 9 is 0.35m above the main roof of the transfer channel, there are 2 pipelines above the drainage culvert 9, namely 10KV power pipe 10 and φ300mm water supply pipe 102, φ300mm water supply pipe 102 is located on one side of the 10KV power pipe 10, the transfer channel phase II foundation pit 1 is 8.5m long, 9.4m wide, and 3.4m high. Because the drainage culvert 9 crosses the transfer channel phase II foundation pit 1, a whole row of continuous bored piles 11 cannot be made, and bored piles 11 and double-tube rotary jet piles 12 need to be constructed separately. The pile diameter of the bored piles 11 constructed is 1000mm, the pile diameter of the double-tube rotary jet piles 12 constructed is 600mm, the pile spacing is 450mm, and the double-tube rotary jet column water stop enters the impermeable layer 1.0m;

[0060] Step 2) Reinforcement construction: The soil on both sides below the drainage culvert 9 is reinforced by bored cast-in-place piles 11, and the bottom sand layer of the transfer channel phase II foundation pit 1 and the soil on both sides below the drainage culvert 9 are reinforced. The soil reinforcement 3 is divided into three times. The first reinforcement: first drill a hole 31 vertically from the original ground, and grout the hole 31 to reinforce the bottom sand layer of the transfer channel phase II foundation pit 1 and stabilize the base soil; the second reinforcement: drill a hole 31 from the direction of the adjacent transfer channel phase I 21, and drill the hole 31 along the horizontal There are 9 rows in the horizontal direction and 5 rows in the vertical direction. Steel flower pipes are used to grout the boreholes 31 to stabilize the soil under the drainage box culvert 9; the third reinforcement: holes are opened between the bored piles 11 on both sides for anchoring, and oblique holes 31 are drilled. There are 10 rows of boreholes 31 in the horizontal direction and 7 rows in the vertical direction. Hollow anchor rods 32 are used to grout the oblique holes 31; the reinforcement construction method of the present invention can solve the problem that the sand layer geology of the second phase foundation pit 1 of the transfer channel is difficult to reinforce;

[0061] Step 3) Protection construction of drainage culvert 9: Make a concave structure of water-stop steel plate 37, select 3mm thick water-stop steel plate 37, and cut the water-stop steel plate 37 into a concave shape, weld angle steel U-shaped buckles 371 on both sides of the water-stop steel plate 37, the welded angle steel U-shaped buckle 371 is 3m thick, the water-stop steel plate 37 is fixed to the side wall of the drainage culvert 9 by the angle steel U-shaped buckles 371 on both sides, and the concave part in the middle of the water-stop steel plate 37 is welded with a steel pipe 38, and the welded steel pipe 38 is 900mm thick. After the installation and fixation of the water-stop steel plate 37 is completed, a brick wall 39 is built to block it. By setting the water-stop steel plate 37 and the brick wall 39, the drainage culvert is blocked at both ends to prevent rainwater intrusion and reduce the weight of the drainage culvert. The built brick wall is 3.1m wide and 2.2m high. It is within the first concrete foundation pit level. A suspension rod 4 is arranged on the support 13, and the drainage culvert 9 is lifted by the suspension rod 4 to protect the drainage culvert 9. A protective channel steel 5 is horizontally placed on the second concrete foundation pit horizontal inner support 14, and the protective channel steel 5 passes through the bottom of the drainage culvert 9 and supports the drainage culvert 9. In specific implementation, when the protective channel steel 5 is horizontally placed, the soil on both sides of the drainage culvert 9 is excavated synchronously. The protective channel steel 5 adopts 40b channel steel @1500mm. The protective channel steel 5 is arranged to support the drainage culvert 9, which can ensure that the soil does not sink during excavation; because water will flow into the drainage culvert 9 from upstream and downstream, the two ends of the drainage culvert 9 are first blocked, and the suspension rod 4 is set on the first concrete foundation pit horizontal inner support 13 to lift it up, and the protective channel steel 5 is horizontally placed on the second concrete foundation pit horizontal inner support 14 to support the drainage culvert 9. Various measures are adopted to protect the drainage culvert.

[0062] Step 4) Continue earth excavation and transfer channel phase II construction; before earth excavation, the density and consolidation strength of grouting filling need to be tested, and the standard penetration method is used for determination. The standard penetration value reaches 10 hits to be qualified, and the test drilling hole 31 is not less than 1% of the total number of grouting holes, and not less than 3 holes;

[0063] Step 5) Enclosure construction of the transfer channel phase I and II docking port: The power pipeline relocation, water retaining wall 6, and temporary enclosure structure 7 of the transfer channel phase I and II are all constructed at night. The water retaining wall 6 is cast with C20 concrete. The cast water retaining wall 6 has a height of 1000 mm and a thickness of 200 mm. The enclosure structure 7 includes an enclosure foundation 71, an enclosure plate 72, and an enclosure fixing member 73. A deep groove 711 is formed at the upper end of the enclosure foundation 71, and an enclosure foot 721 is formed at the bottom of the enclosure plate 72. The enclosure foot 721 at the bottom of the enclosure plate 72 is embedded in the deep groove 711 and fixed by the enclosure fixing member 73, and then the deep groove 711 of the enclosure foundation 71 is filled with mortar;

[0064] Step 6) Excavation and construction of the transfer channel phase I and II docking ports: demolish the side walls, and demolish the transfer channel phase I 21 and the transfer channel phase II respectively;

[0065] Step 7) Construction of the transfer channel phases 1 and 2 docking points.

[0066] Step 8) The first and second phases of the transfer channel are completed.

[0067] When the present invention is implemented, the soil on both sides below the drainage box culvert 9 is reinforced for the third time by grouting with hollow anchor rods 32 and connecting the bored piles 11 at both ends with concrete retaining walls 33. The soil on both sides below the drainage box culvert 9 is excavated from top to bottom. After each excavation layer, the hollow anchor rods 32 are immediately used for grouting reinforcement in a plum blossom pattern. Then, the steel mesh is hung on the hollow anchor rods 32, and then slurry is sprayed on the steel mesh. Then, several layers of horizontal grid steel frames 34 are installed. After several layers of horizontal grid steel frames 34 are installed, concrete is finally sprayed to form a concrete retaining wall 33. Among them, the thickness of the concrete retaining wall 33 is 400 mm, the height of each excavation layer is 0.8 m, the concrete retaining wall 33 contains the horizontal grid steel frame 34, and then the excavation is carried out downward. Among them, several layers of horizontal grid steel frames 34 are placed layer by layer from the bottom of the transfer channel phase II foundation pit 1 to the bottom of the drainage culvert 9, and several layers of horizontal grid steel frames 34 are connected into an integrated structure by longitudinal connecting ribs 35. The horizontal spacing between two adjacent layers of horizontal grid steel frames 34 is 1m. The longitudinal connecting bars 35 are made of No. 7 B20 steel bars. The vertical spacing between two adjacent layers of horizontal grid steel frames 34 is 0.4m. In specific implementation, at least one connecting steel bar 36 is provided between two adjacent layers of horizontal grid steel frames 34. The two adjacent layers of horizontal grid steel frames 34 are connected by the connecting steel bars 36 to form a "pin"-shaped structure. The connecting steel bars 36 are made of No. 7 B18 steel bars. Each layer of horizontal grid steel frame 34 includes four main supporting bars 341 and a plurality of annular ring bars 342. The plurality of annular ring bars 342 are evenly distributed on the four main supporting bars 341 at longitudinal intervals. Each annular ring bar 342 surrounds the outer periphery of the four main supporting bars 341 and is welded thereto. The four main supporting bars 341 are connected by a plurality of annular ring bars 342 to form a horizontal grid steel frame 34. The cross section of the horizontal grid steel frame 34 is rectangular. On multiple sides of the rectangle formed by the four main supporting bars 341, oblique reinforcing bars 343 are fixed between two adjacent annular ring bars 342.

[0068] In the embodiment of the present invention, the bored pile 11 is connected to the concrete retaining wall 33, and the bored pile 11 is chiseled to expose the steel bar, and the exposed steel bar is connected to the steel bar of the concrete retaining wall 33 by welding. The retaining structure of the second phase foundation pit 1 of the transfer channel of the present invention adopts the retaining structure form of 8 bored piles 11 + double-tube rotary jet piles 12 + the first concrete foundation pit horizontal inner support 13, the second concrete foundation pit horizontal inner support 14, and the two sides below the drainage box culvert 9 adopt hollow anchor rods 32 grouting + 400mm thick concrete retaining wall 33 to connect the bored piles 11 at both ends, and two vertical concrete foundation pit horizontal inner supports, a total of six. The construction method of the present invention uses cement slurry to reinforce the soil 3 to stop water on both sides of the soil below the drainage culvert 9 near the bored piles 11. When the second phase foundation pit 1 of the transfer channel is excavated, the bored piles 11 on both sides of the drainage culvert 9 are connected with a concrete retaining wall 33 on the inner side of the foundation pit. Before the construction of the bored piles 11, the covering soil above the drainage culvert 9 is excavated to accurately locate the positions of the drainage culvert 9 and the 10KV power pipe 10 to avoid conflicts between the bored piles 11 and the underground power pipelines and the drainage culvert 9. The power pipelines and the drainage culvert 9 can be protected, and the normal operation of the drainage culvert 9 is ensured, the structural safety and stability of the transfer channel subway station 2 is guaranteed, and the construction efficiency of the first and second phases of the transfer channel is improved.

[0069] like Figure 14-16 As shown, when step 1) of the present invention is specifically implemented, a steel ring 111 is pre-buried in the pile body of the bored pile 11, and the height of the steel ring 111 is from the bottom of the drainage box culvert 9 to the bottom of the second phase foundation pit 1 of the transfer channel. The steel ring 111 is welded with several layers of vertical steel plates 112, and the size of the vertical steel plates 112 is 300*600mm. Two supporting main bars 341 of the horizontal grid steel frame 34 are welded to the vertical steel plates 112 respectively. The steel ring 111 of the bored pile 11 is fixed with five steel ring anchor bars 113 in the vertical direction, and the spacing between two adjacent steel ring anchor bars 113 is 300mm. The five steel ring anchor bars 113 are arranged radially, and the steel ring anchor bars 113 are anchored into the pile body of the bored pile 11, and the steel ring anchor bars 113 are U-shaped anchor bars.

[0070] like Fig.13As shown, when step 3) of the present invention is specifically implemented, the 10KV power pipe 10 above the drainage culvert 9 is suspended and protected by a suspension structure 101, a suspension point is set at every 1m on the wall, and an expansion bolt 1013 is fixed at the suspension point. The suspension structure 101 includes a sleeve, a suspension rope 1011, and a basket bolt 1012. The sleeve is wrapped around the outer surface of the 10KV power pipe 10, one end of the suspension rope 1011 is sleeved around the sleeve wrapped with the 10KV power pipe 10, and the other end of the suspension rope 1011 is connected to one end of the basket bolt 1012, and the other end of the basket bolt 1012 is fixed to the suspension point by the expansion bolt 1013, wherein the sleeve adopts 20mmPVC, the suspension rope 1011 adopts 6×19A16 steel wire rope, the suspension rope 1011 is fixed by the basket bolt 1012, and the basket bolt 1012 is fixed to the wall with the expansion bolt 1013.

[0071] like Figure 20-21 As shown, in an embodiment of the present invention, the enclosure plate 72 in step 5) includes an outer lightweight steel plate 722, an inner lightweight steel plate 723, and sound insulation cotton 724, which are arranged in sequence from the outside to the inside. The sound insulation cotton 724 is sandwiched between the outer lightweight steel plate 722 and the inner lightweight steel plate 723. The enclosure foundation 71 is cast with C20 concrete. The width of the enclosure foundation 71 is 300 mm and the height is 250 mm. The height of the deep groove 711 is 100 mm. Bolts can be used for the enclosure fixing parts 73. The main purpose of constructing the retaining wall 6 of the present invention is to prevent construction sewage from entering the operating station. The enclosure structure 7 is constructed, and the enclosure structure 7 is fully closed at the top and bottom. The sound insulation cotton 724 is sandwiched in the middle of the enclosure plate 72, which can achieve the effect of isolating noise and dust.

[0072] like Fig. 22 As shown, the excavation construction of the first and second phase connection ports of the transfer channel in step 6 of the present invention specifically includes:

[0073] Step 61) The first phase of the transfer channel 21 is excavated first, and the side walls of the three steel support positions of the first phase of the transfer channel 21 are first demolished, and then the temporary first vertical steel support 83, the second vertical steel support 84, and the third vertical steel support 85 are erected; among them, the first vertical steel support 83, the second vertical steel support 84, and the third vertical steel support 85 are all made of Q235 steel pipes with a diameter of φ609mm and a wall thickness of 14mm.

[0074] Step 62) The rest of the main body side wall of the transfer channel phase II is excavated. The main body side wall is excavated in blocks, and is excavated from top to bottom in the order of transfer channel phase I 21 → transfer channel phase II. The excavation is carried out by water drill + rope saw. First, a water drill is used to drill holes 31 at the four corners of each small block, and then the rope saw is used to cut and pull out. The block size is 1m×0.82m. The block removal of the side wall by water drill + rope saw can reduce the impact of vibration on the existing line.

[0075] like Fig.23 As shown, in step 7), the specific construction process of the transfer channel phase I and II interface construction includes:

[0076] Step 71) constructing hidden column 8;

[0077] Step 72) constructing the first phase of the transfer channel and pouring concrete beams 81;

[0078] Step 73) Temporary steel support is set under the 21 concrete beam of the first phase of the transfer channel;

[0079] Step 74) dismantle the first vertical steel support 83, the second vertical steel support 84, and the third vertical steel support 85;

[0080] Step 75) Construct the second phase of the transfer channel and cast concrete beams 86.

[0081] Step 76) Remove temporary steel supports, restore original decoration, remove retaining wall 6 and enclosure structure 7, waterproof the interface of transfer channel phase II foundation pit 1, embed grouting conduits in the bottom plate of the interface of transfer channel phase II foundation pit 1 for grouting reinforcement, and ensure that the joints are caulked to form a sealed and continuous waterproof wall. The grouting conduits are connected by overlapping with a width of 20mm-30mm and a spacing of 8-13m. The openings of the grouting conduits are temporarily blocked to prevent foreign matter from entering.

[0082] The entire interface construction process of the first and second phases of the transfer channel of the present invention is carried out symmetrically and synchronously. The second phase post-cast beam of the transfer channel can only be constructed after the strength of the first phase 21 concrete beam of the transfer channel reaches 100%.

[0083] Compared with the prior art, the technical solution disclosed in the above embodiment has the following beneficial effects:

[0084] In the above embodiment, the construction method of the present invention reinforces the bottom sand layer of the second phase foundation pit 11 of the transfer channel and the soil on both sides below the drainage culvert 9, blocks both ends of the drainage culvert 9, sets a suspension rod 44 on the first concrete foundation pit horizontal inner support 13, and horizontally places a protective channel steel 5 on the second concrete foundation pit horizontal inner support 14. The protective channel steel 5 passes through the bottom of the drainage culvert 9, and the protective channel steel 5 is set to support the drainage culvert 9. Multiple protection measures are adopted to protect the drainage culvert 9, and cement slurry is used to reinforce the soil on both sides of the drainage culvert 9 near the bored piles 11. To stop water, the bored cast-in-place piles 11 on both sides of the drainage culvert 9 are connected with a concrete retaining wall 33 on the inner side of the foundation pit 11 of the second phase of the transfer channel. Before the construction of the bored cast-in-place piles 11, the covering soil above the drainage culvert 9 is excavated to accurately locate the positions of the drainage culvert 9 and the 10KV power pipe 10 to avoid conflicts between the bored cast-in-place piles 11 and the underground pipelines and the drainage culvert 9. The construction method of the present invention can ensure the normal operation of the drainage culvert 9, ensure the safety and stability of the structure of the transfer channel of the transportation hub, improve the construction efficiency of the first and second phases of the transfer channel, and solve the problem that the sand layer geology of the second phase of the transfer channel is difficult to reinforce.

[0085] The above description has been a detailed description of the present invention. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present application. That is, all equivalent changes and modifications made within the scope of the present application should still fall within the scope of the present invention.

Claims

1. A construction method for box culvert protection of a transfer channel in a comprehensive transportation hub, characterized by: The construction method for the connection of the first phase and the second phase of the transfer channel of the comprehensive transportation hub includes the following processes: Step 1) Construction of support for the foundation pit of the transfer channel phase II: The drainage box culvert spans the foundation pit of the transfer channel phase II. The two sides of the foundation pit of the transfer channel phase II are adjacent to the subway station entrance and the transfer channel phase I respectively. The other two sides of the foundation pit of the transfer channel phase II are constructed with bored piles and double-tube rotary jet piles respectively. The bored piles and double-tube rotary jet piles pass through the bottom sand layer of the foundation pit of the transfer channel phase II. Step 2) Reinforcement construction: The soil on both sides below the drainage culvert is close to the bored cast-in-place piles, and the bottom sand layer of the transfer channel phase II foundation pit and the soil on both sides below the drainage culvert are reinforced. The soil reinforcement is divided into three times. The first reinforcement: first drill vertically from the original ground, drill and grout to reinforce the bottom sand layer of the transfer channel phase II foundation pit and stabilize the base soil; the second reinforcement: drill from the direction of the adjacent transfer channel phase I, use steel flower pipes to grout the drilled holes to stabilize the soil under the drainage culvert; the third reinforcement: open holes for anchoring between the bored cast-in-place piles on both sides, drill obliquely, and use hollow anchor rods for oblique drilling and grouting; Step 3) Drainage culvert protection construction: make a concave structure water-stop steel plate, weld angle steel U-shaped buckles on both sides of the water-stop steel plate, fix the water-stop steel plate to the side wall of the drainage culvert through the angle steel U-shaped buckles on both sides, build brick walls to seal the two ends of the drainage culvert after the water-stop steel plate is installed and fixed, and simultaneously carry out earthwork excavation on both sides of the drainage culvert, set a suspension rod on the first concrete foundation pit horizontal inner support, use the suspension rod to lift the drainage culvert to protect the drainage culvert, and horizontally place a protective channel steel on the second concrete foundation pit horizontal inner support, and the protective channel steel passes through the bottom of the drainage culvert and supports the drainage culvert; Step 4) Continue to excavate the bottom of the drainage box culvert and construct the second phase of the transfer channel; Step 5) Enclosure construction of the transfer channel phase I and II docking ports: The power pipeline relocation, retaining wall, and temporary enclosure structure of the transfer channel phase I and II are all constructed at night. The enclosure structure includes an enclosure foundation, an enclosure plate, and an enclosure fixing. A deep groove is formed at the upper end of the enclosure foundation, and an enclosure foot is formed at the bottom of the enclosure plate. The enclosure foot at the bottom of the enclosure plate is embedded in the deep groove and fixed by the enclosure fixing, and then the deep groove of the enclosure foundation is filled with mortar; Step 6) Excavation and construction of the transfer channel phase I and II docking ports: demolish the side walls, and demolish the transfer channel phase I and phase II respectively; Step 7) Construction of the transfer channel phases 1 and 2 docking points. Step 8) The first and second phases of the transfer channel are completed.

2. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 1 is characterized by: In step 2), the soil on both sides below the drainage culvert is reinforced for the third time by grouting with hollow anchor rods and bored piles at both ends of the concrete retaining wall connection. The soil on both sides below the drainage culvert is excavated from top to bottom. After each excavation layer, hollow anchor rods are immediately used for grouting reinforcement in a plum blossom shape. Then, the steel mesh is hung on the hollow anchor rods, and then slurry is sprayed on the steel mesh. Then, several layers of horizontal grid steel frames are installed. After several layers of horizontal grid steel frames are installed, concrete is finally sprayed to form a concrete retaining wall.

3. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 2 is characterized by: The bored piles are connected to the concrete retaining wall, and the bored piles are chiseled to expose the steel bars, which are then connected to the steel bars of the concrete retaining wall by welding.

4. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 2 is characterized by: Several layers of horizontal grid steel frames are placed layer by layer from the bottom of the second phase foundation pit of the transfer channel to the bottom of the drainage box culvert. Several layers of horizontal grid steel frames are connected into an integrated structure by longitudinal connecting reinforcements. The horizontal spacing between two adjacent layers of horizontal grid steel frames is 1m.

5. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 4 is characterized by: Each layer of horizontal grid steel frame includes four supporting main bars and a number of annular ring bars. The annular ring bars are evenly distributed on the four supporting main bars at longitudinal intervals. Each annular ring bar surrounds the outer circumference of the four supporting main bars and is welded to them. The four supporting main bars are connected by a number of annular ring bars to form a horizontal grid steel frame.

6. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 1 is characterized by: In step 1), a steel ring is pre-buried in the pile body of the bored pile, and the height of the steel ring is from the bottom of the drainage box culvert to the bottom of the second phase foundation pit of the transfer channel. The steel ring is welded with several layers of vertical steel plates, and two supporting main bars of the horizontal grid steel frame are welded with vertical steel plates respectively. Five steel ring anchor bars are fixed in the vertical direction on the steel ring of the bored pile. The five steel ring anchor bars are arranged radially, and the steel ring anchor bars are anchored into the pile body of the bored pile.

7. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 6 is characterized by: The 10KV power pipe above the drainage culvert in step 3) is suspended and protected by a suspension structure. A suspension point is set on the wall every 1m, and an expansion bolt is fixed at the suspension point. The suspension structure includes a casing, a suspension rope, and a basket bolt. The casing is wrapped around the outer surface of the 10KV power pipe. One end of the suspension rope is wrapped around the casing wrapped with the 10KV power pipe, and the other end of the suspension rope is connected to one end of the basket bolt. The other end of the basket bolt is fixed to the suspension point through the expansion bolt.

8. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 1 is characterized by: In step 5), the enclosure plate includes an outer lightweight steel plate, an inner lightweight steel plate, and sound insulation cotton which are arranged in sequence from the outside to the inside, the sound insulation cotton is sandwiched between the outer lightweight steel plate and the inner lightweight steel plate, and the enclosure foundation is cast with C20 concrete.

9. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 1 is characterized by: In step 6), the excavation construction of the transfer channel phase I and II docking port specifically includes: Step 61) The first phase of the transfer channel is excavated first, and the side walls of the three steel support positions are removed first, and then the temporary first vertical steel support, the second vertical steel support, and the third vertical steel support are erected; Step 62) The remaining part of the main side wall of the transfer channel phase II is excavated. The main side wall is excavated in blocks, from top to bottom in the order of transfer channel phase I → transfer channel phase II. The excavation is carried out using a water drill + rope saw method. First, a water drill is used to drill holes in the four corners of each small block, and then the rope saw is used to cut and pull out. The block size is 1m×0.82m.

10. The construction method for box culvert protection of a transfer channel in a comprehensive transportation hub according to claim 1, characterized in that: In step 7), the specific construction process of the interface construction of the transfer channel phase I and II includes: Step 71) constructing hidden columns; Step 72) constructing the first phase of the transfer channel and pouring concrete beams; Step 73) Temporary steel supports are set under the first phase concrete beams of the transfer channel; Step 74) dismantling the first vertical steel support, the second vertical steel support, and the third vertical steel support; Step 75) Construct the second phase of the transfer channel and pour concrete beams. Step 76) Remove temporary steel supports, restore original decoration, remove retaining walls and enclosure structures, waterproof the interface of the transfer channel phase II foundation pit, embed grouting conduits in the bottom plate of the transfer channel phase II foundation pit interface for grouting reinforcement to ensure that the joints are caulked to form a sealed and continuous waterproof wall.

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