A prefabricated structure and construction method for urban open-cut tunnel

Abstract

The application relates to the technical field of underground structure engineering, in particular to a prefabricated structure and a construction method for urban open-cut tunnels. The prefabricated structure for urban open-cut tunnels comprises a prefabricated pile wall, a prefabricated track and prefabricated units, the opposite wall surfaces of the prefabricated pile wall are provided with pile wall connecting grooves extending in the front-rear direction, and the prefabricated track is poured on the ground; the prefabricated units comprise two end prefabricated units and at least two assembled prefabricated units, the end prefabricated units and the assembled prefabricated units each comprise a bottom base, side walls integrally poured on the left and right ends of the bottom base, a top wall integrally poured on the top of the side walls, and a partition wall integrally poured between the top wall and the bottom base, the bottom base is provided with a bottom base connecting groove and a bottom base grouting pipe in sliding fit with the prefabricated track; the side walls are provided with side wall connecting blocks, side wall grouting pipes and gap grouting pipes in sliding fit with the prefabricated pile wall; the adjacent prefabricated units are in plug-in fit and are provided with plug-in grouting pipes. The prefabricated structure is combined with cast-in-situ, and the construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of underground structure engineering technology, and in particular to a prefabricated structure and construction method for an urban open-cut tunnel. Background Technology

[0002] Tunnels are structures built underground, underwater, or within mountains to carry railways or highways for motor vehicles, or to transport fuels (natural gas, oil, etc.). In recent years, building tunnels under main roads in large urban centers to solve traffic congestion has become a common solution for urban development, economic growth, and traffic management.

[0003] Currently, tunnel excavation methods include the following: cut-and-cover, shallow-buried tunneling, and shield tunneling. However, due to constraints imposed by the surrounding environment and traffic functions, most tunnel construction still relies on the traditional cut-and-cover method. Traditional cut-and-cover tunnels refer to a construction method where excavation proceeds layer by layer and section by section from the ground surface until the required dimensions and elevation for the tunnel bottom structure are reached. Then, the main tunnel structure and auxiliary structures such as waterproofing and insulation are constructed inside the pit, followed by backfilling. After the pit excavation and support structure construction are completed, the main tunnel structure is poured in sections and layers from the bottom of the pit, or precast components are used. Then, the support structure inside the pit is removed, and this process is repeated until the tunnel top structure is reached.

[0004] The cut-and-cover tunnel construction method involves a series of procedures, including foundation pit excavation, rebar tying, formwork fabrication, concrete pouring and curing, and backfilling. From the overall construction process perspective, it is complex, has a long construction period, causes significant and prolonged disruption to the surrounding environment, and incurs substantial losses of manpower, materials, and machinery, severely compressing the cost-effectiveness ratio. Furthermore, this method is greatly affected by environmental conditions such as rainfall, fog, and temperature, making it difficult to control construction quality and schedule. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a prefabricated structure and construction method for urban open-cut tunnels, so as to solve the technical problems of long construction period and complex construction procedures in existing open-cut tunnel construction methods.

[0006] To achieve the above objectives, the technical solution adopted by the prefabricated structure of the urban open-cut tunnel of the present invention is as follows:

[0007] The prefabricated structure of urban cut-and-cover tunnels includes:

[0008] The precast pile wall has two sides arranged in parallel and spaced apart. The precast pile wall part is buried in the ground. The length direction of the precast pile wall is defined as the front-to-back direction, and the thickness direction is defined as the left-to-right direction. The two sides of the precast pile wall have pile wall connection grooves extending in the front-to-back direction on the opposite wall surfaces.

[0009] The precast track is located between two precast side walls and cast on the ground, extending in the front-to-back direction and arranged at least two tracks at intervals in the left-to-right direction.

[0010] The precast unit includes two end precast units and at least two assembled precast units located between the two end precast units. Both the end precast units and the assembled precast units include a foundation, side walls integrally cast at both ends of the foundation, a top wall integrally cast on top of the side walls, and a central partition wall integrally cast between the top wall and the foundation. The foundation has a foundation connection groove that slides with a precast track. A foundation grouting pipe extending in the front-rear direction is fixedly connected to the bottom and sidewalls of the foundation connection groove. The foundation grouting pipe slides in contact with the precast track when the corresponding precast unit moves relative to the precast track. A sidewall connection block integrally cast on the side wall slides with the pile-wall connection groove. The sidewall connection block has corresponding sidewalls and bottoms of the pile-wall connection groove. All surfaces are fixedly connected with side wall grouting pipes extending in the front-to-back direction. The side wall grouting pipes are used to slide in contact with the pile wall connection groove. The side wall facing the precast pile wall is also provided with multiple gap grouting pipes extending in the vertical direction and spaced in the front-to-back direction. The gap grouting pipes slide in contact with the wall surface of the precast pile wall. In adjacent end precast units and assembled precast units, as well as in two adjacent assembled precast units, one precast unit is provided with an integrally cast plug-in block, and the other precast unit is provided with a plug-in groove that matches the plug-in block. Plug-in grouting pipes are fixedly connected to the surfaces of the plug-in block corresponding to the groove sidewall and groove bottom of the plug-in groove. Multiple joint grouting pipes extending in the vertical direction are provided between the joints of two adjacent precast units.

[0011] The foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe and splice grouting pipe are all provided with multiple grout outlet holes in the circumference;

[0012] In the front-to-back direction, adjacent foundation grouting pipes and adjacent sidewall grouting pipes are connected to each other through connectors.

[0013] Furthermore, the grouting pipe is pre-embedded in the side wall connecting block, with the bottom end of the grouting pipe flush with the bottom surface of the foundation and the top end of the grouting pipe extending out of the top wall.

[0014] Furthermore, each grouting pipe on the same side wall connection block is connected to a grouting branch pipe. One end of the grouting branch pipe is open, and the other end is coaxially connected to an insert pipe. The outer diameter of the insert pipe is smaller than the outer diameter of the grouting branch pipe. The insert pipe is used to connect with the grouting branch pipe on the adjacent side wall connection block to connect the grouting branch pipes.

[0015] Preferably, the joint grouting pipe and the plug-in grouting pipe on the same end prefabricated unit or the same assembled prefabricated unit are interconnected.

[0016] Furthermore, all end prefabricated units and all assembled prefabricated units have interconnected joint grouting pipes and plug-in grouting pipes.

[0017] Preferably, the diameters of the foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe, and splice grouting pipe are all the same.

[0018] The technical solution of the construction method for urban open-cut tunnels of the present invention is as follows:

[0019] The construction method for urban cut-and-cover tunnels includes the following steps:

[0020] Step 1: Excavate the foundation pit;

[0021] Step 2: Construct two precast pile walls in the foundation pit and pour a precast track between the precast pile walls; pile wall connection grooves extending in the front-to-back direction are provided on the opposite walls of the two precast pile walls.

[0022] Step 3: Prefabricate the end prefabricated units and the assembly prefabricated units. Both end prefabricated units and assembly prefabricated units include a foundation, side walls integrally cast at both ends of the foundation, a top wall integrally cast on top of the side walls, and a central partition wall integrally cast between the top wall and the foundation. The foundation has a foundation connection groove that slides with the prefabricated track. A foundation grouting pipe extending in the front-to-back direction is fixedly connected to the bottom and sidewalls of the foundation connection groove. Side wall connection blocks integrally cast with the pile-wall connection groove are fixedly connected to the surfaces of the sidewalls and bottoms of the pile-wall connection groove. The wall is connected to a grouting pipe extending in the front-to-back direction; the side wall facing the precast pile wall is also provided with multiple gap grouting pipes extending in the vertical direction and spaced apart in the front-to-back direction; in adjacent end precast units and assembled precast units, as well as in two adjacent assembled precast units, one precast unit is provided with an integrally cast plug-in block, and the other precast unit is provided with a plug-in groove adapted to the plug-in block. Plug-in grouting pipes are fixedly connected to the surfaces of the plug-in block corresponding to the groove sidewall and groove bottom of the plug-in groove. Multiple joint grouting pipes extending in the vertical direction are provided between the joints of two adjacent precast units.

[0023] Step 4: Use hoisting equipment to lift the end prefabricated units and the assembled prefabricated units onto the prefabricated track, and use power equipment to push the end prefabricated units and the assembled prefabricated units horizontally to the construction position to complete the assembly between the end prefabricated units, the assembled prefabricated units, and the prefabricated pile wall; when the power equipment is working, the foundation grouting pipe slides in contact with the prefabricated track, the side wall grouting pipe slides in contact with the pile wall connection groove, and the gap grouting pipe slides in contact with the wall surface of the prefabricated pile wall;

[0024] Step 5: Grouting is performed into each foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe, and joint grouting pipe. The grout flows out from the grout outlet on each grouting pipe, filling the gaps between the end precast unit and the precast pile wall, the gaps between the end precast unit and the adjacent assembled precast unit, the gaps between two adjacent assembled precast units, and the gaps between each end precast unit, each assembled precast unit, and the precast track.

[0025] Preferably, in step three, when prefabricating the prefabricated end unit and assembling the prefabricated unit, the grouting pipes of each gap on the same prefabricated unit are connected in advance through grouting branch pipes, and an insert pipe is set at one end of the grouting branch pipe; in step four, during assembly, the insert pipe is inserted into the grouting branch pipe on the adjacent side wall connecting block, and this operation is repeated to connect all the grouting branch pipes.

[0026] Preferably, the gap grouting pipe, the plug grouting pipe, and the splice grouting pipe all extend outside the top wall. In step five, before pouring the concrete grout, all the plug grouting pipes and all the splice grouting pipes are connected to each other, and all the foundation grouting pipes are connected to each other.

[0027] Preferably, the diameters of the foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe, and splice grouting pipe are all the same.

[0028] The beneficial effects of this invention are:

[0029] 1. This invention divides the tunnel into multiple prefabricated units. These units can be prefabricated within the foundation pit and then assembled. During assembly, each unit is simply hoisted onto a prefabricated track by hoisting equipment. Guided by the track and the pile-wall connection groove, the units are smoothly and accurately assembled in their designated positions. Finally, grouting is injected into various grouting pipes to fill the gaps between the components. The prefabricated track itself becomes part of the tunnel without needing to be dismantled. The entire construction process is simple, shortens the construction cycle, and reduces the consumption of manpower, materials, and machinery.

[0030] 2. Before pouring concrete, connect all grouting branch pipes, all plug-in grouting pipes and all joint grouting pipes, and connect all foundation grouting pipes to each other. During a single pour, grout can be injected into multiple grouting pipes simultaneously, improving grouting efficiency and thus construction efficiency.

[0031] 3. All grouting pipes are the same size, making it easy to source materials and reducing usage costs.

[0032] 4. This invention combines prefabricated structures with cast-in-place construction, which accelerates the construction progress of open-cut tunnels and ensures construction quality. Attached Figure Description

[0033] Figure 1 This is a front view of the prefabricated structure of the urban open-cut tunnel of the present invention;

[0034] Figure 2 This is a top view of the prefabricated structure of the urban open-cut tunnel of the present invention;

[0035] Figure 3 This is a schematic diagram of the prefabricated end unit and the assembled prefabricated unit in the prefabricated structure of the urban open-cut tunnel of the present invention after assembly;

[0036] Figure 4 This is a side view of the end prefabricated unit in the prefabricated structure of the urban open-cut tunnel of the present invention (the plug-in block and plug-in slot are not shown).

[0037] Explanation of reference numerals in the attached drawings: 1-Precast track, 2-Precast pile wall, 3-Side wall, 4-Top wall, 5-Intermediate partition wall, 6-Foundation, 7-Side wall connecting block, 8-Pile wall connecting groove, 9-Foundation connecting groove, 10-Foundation grouting pipe, 11-Gap grouting pipe, 12-Side wall grouting pipe, 13-Inserted grouting pipe, 14-Joint grouting pipe, 15-Grouting hole, 16-Connector, 17-Grouting branch pipe, 18-Inserted pipe, 19-Inserted block, 20-Inserted groove. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] Specific embodiments of the prefabricated structure for urban cut-and-cover tunnels of the present invention:

[0040] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the prefabricated structure of the urban open-cut tunnel includes prefabricated pile wall 2, prefabricated track 1 and multiple prefabricated units.

[0041] Specifically, the precast pile wall 2 has two parallel and spaced sides, and the length of the precast pile wall 2 is the same as the length of the tunnel. The precast pile wall 2 is partially buried in the ground. The length direction of the precast pile wall 2 is defined as the front-to-back direction, and the thickness direction is defined as the left-to-right direction. The opposing walls of the two precast pile walls 2 are provided with pile wall connection grooves 8 extending in the front-to-back direction.

[0042] The precast track 1 is located between two precast side walls 2 and is cast on the ground. It extends in the front-to-back direction and is arranged in two intervals in the left-to-right direction.

[0043] In this embodiment, the prefabricated unit includes two end prefabricated units and two assembly prefabricated units located between the two end prefabricated units. Of course, in other embodiments, the number of assembly prefabricated units can be appropriately determined based on the tunnel length; for example, if the tunnel is too long, it can be divided into three or more assembly prefabricated units. Figure 1 As shown, both the end prefabricated unit and the assembled prefabricated unit include a base 6, side walls 3 integrally cast at the left and right ends of the base 6, a top wall 4 integrally cast on top of the side walls 3, and a central partition wall 5 integrally cast between the top wall 4 and the base 6.

[0044] Each foundation 6 is provided with a foundation connection groove 9 that slides with two precast tracks 1. A foundation grouting pipe 10 extending in the front-to-back direction is fixedly connected to the bottom and sidewall of the foundation connection groove 9. The foundation grouting pipe 10 slides in contact with the precast track 1 when the corresponding precast unit moves relative to the precast track 1. A sidewall connection block 7 is integrally cast on the sidewall 3, slidingly engaging with the pile-wall connection groove 8. The front and rear ends of the sidewall connection block 7 are flush with the front and rear ends of the sidewall 3, respectively. A sidewall grouting pipe 12 extending in the front-to-back direction is fixedly connected to the surface of the sidewall connection block 7 corresponding to the sidewall and bottom of the pile-wall connection groove 8. The sidewall grouting pipe 12 is used for sliding contact with the pile-wall connection groove 8. Figure 4 As shown, the side wall 3 facing the precast pile wall 2 is also provided with multiple slot grouting pipes 11 extending vertically and spaced apart in the front-back direction. The slot grouting pipes 11 slide in contact with the wall surface of the precast pile wall 2. The slot grouting pipes 11 are embedded in the side wall connecting block 7. The bottom end of the slot grouting pipe 11 is flush with the bottom surface of the foundation 6, and the top end of the slot grouting pipe 11 extends out of the top wall 4.

[0045] like Figure 2 and Figure 3 As shown, in the two end prefabricated units, one end prefabricated unit has an integrally cast plug-in block 19, and the other end prefabricated unit has a plug-in groove 20 that matches the plug-in block 19. Additionally, each assembled prefabricated unit has a plug-in block 19 at one end and a plug-in groove 20 at the other end. It should be noted that the plug-in block 19 is integrally cast with the side wall 3, top wall 4, central partition wall 5, and foundation 6. Figure 2 and Figure 3 It can be seen that in adjacent end prefabricated units and assembled prefabricated units, as well as in two adjacent assembled prefabricated units, the plug-in block 19 on one prefabricated unit is plugged into the plug-in slot 20 on the other prefabricated unit. A plug-in grouting pipe 13 is fixedly connected to the surfaces of the plug-in block 19 corresponding to the sidewall and bottom of the plug-in slot 20, and the plug-in grouting pipe 13 extends in the vertical direction. Multiple joint grouting pipes 14 extending in the vertical direction are provided between the joints of two adjacent prefabricated units.

[0046] In the front-back direction, two adjacent corresponding foundation grouting pipes 10 and two adjacent corresponding side wall grouting pipes 12 are connected to each other through connectors 16, and grouting holes are also provided in the circumferential direction of connectors 16.

[0047] In this embodiment, all the foundation grouting pipes 10, sidewall grouting pipes 12, gap grouting pipes 11, plug-in grouting pipes 13, and joint grouting pipes 14 have the same diameter, and each has multiple grout outlet holes 15 in the circumferential direction. For example... Figure 4 As shown, taking the end prefabricated unit as an example, each gap grouting pipe 11 on the same side wall connecting block 7 is connected to a grouting branch pipe 17. One end of the grouting branch pipe 17 is open, and the other end is coaxially connected to an insertion pipe 18. The outer diameter of the insertion pipe 18 is smaller than the outer diameter of the grouting branch pipe 17. The insertion pipe 18 is used to connect with the grouting branch pipes on adjacent side wall connecting blocks. After each end prefabricated unit is assembled with each assembled prefabricated unit, each grouting branch pipe 17 is interconnected.

[0048] In addition, the joint grouting pipes 14 and plug-in grouting pipes 13 on the same end precast unit and the same assembled precast unit are also interconnected, which facilitates the filling of concrete grout from one grouting pipe and ensures that concrete grout can flow out from each grouting pipe. It should be noted that both the joint grouting pipe 14 and the plug-in grouting pipe 13 extend outside the top wall 4, but the grout outlet holes 15 on them are all located in the corresponding gaps.

[0049] In actual construction, to save construction time, all end prefabricated units and all assembled prefabricated units are interconnected with each other, including the joint grouting pipes 14 and the plug-in grouting pipes 13, so that grouting can be poured in one go. When connecting, multiple grouting main pipes can be used, with multiple interfaces set on each grouting main pipe. Short pipes and connectors are used to detachably connect the corresponding joint grouting pipes 14 and plug-in grouting pipes 13 at the interfaces. At the same time, multiple grouting main pipes are connected, and grout is pumped into the grouting main pipe.

[0050] After grouting, the gaps between the end precast units and the precast pile wall 2, the gaps between the end precast units and the adjacent assembled precast units, the gaps between two adjacent assembled precast units, and the gaps between each end precast unit, each assembled precast unit and the precast track 1 are all filled with concrete grout, forming an integral tunnel.

[0051] In other embodiments, different diameter grouting pipes, such as foundation grouting pipes, sidewall grouting pipes, gap grouting pipes, plug-in grouting pipes, and splice grouting pipes, can be used depending on the size of the specific gap.

[0052] In other embodiments, the grouting pipes on the same sidewall connecting block can also be independent of each other, and a main grouting pipe is used to connect the various grouting pipes during pouring. Similarly, the joint grouting pipes and plug grouting pipes on the same end prefabricated unit or the same assembled prefabricated unit can also be independent of each other, and a connecting pipe is used to connect them during pouring.

[0053] Specific embodiments of the construction method for urban open-cut tunnels of the present invention:

[0054] It should be noted that the construction method for urban open-cut tunnels in this embodiment is based on the prefabricated structure of urban open-cut tunnels described in the above embodiment. Therefore, the relevant structures are used directly and will not be described in detail. Figures 1 to 4 As shown, the specific steps include:

[0055] Step 1: Excavate the foundation pit;

[0056] Step 2: Construct two precast pile walls 2 in the foundation pit, and pour a precast track 1 between the precast pile walls 2; pile wall connection grooves 8 extending in the front-to-back direction are provided on the opposite wall surfaces of the two precast pile walls 2.

[0057] Step 3: Prefabricate the end prefabricated units and the assembly prefabricated units. Both the end prefabricated units and the assembly prefabricated units include a foundation 6, side walls 3 integrally cast at both ends of the foundation 6, a top wall 4 integrally cast on top of the side walls 3, and a central partition wall 5 integrally cast between the top wall 4 and the foundation 6. The foundation 6 is provided with a foundation connecting groove 9 that slides with the prefabricated track 1. A foundation grouting pipe 10 extending in the front-to-back direction is fixedly connected to the bottom and side walls of the foundation connecting groove 9. A side wall connecting block 7 integrally cast on the side wall 3 that slides with the pile-wall connecting groove 8 is fixedly connected to the surface of the side wall connecting block 7 corresponding to the side wall and bottom of the pile-wall connecting groove 8. The side wall is connected to a grouting pipe 12 extending in the front-to-back direction; the side wall 3 facing the precast pile wall 2 is also provided with a number of gap grouting pipes 11 extending in the vertical direction and spaced apart in the front-to-back direction; in the adjacent end precast units and the assembled precast units, as well as in two adjacent assembled precast units, one precast unit is provided with an integrally cast plug block 19, and the other precast unit is provided with a plug groove 20 adapted to the plug block 19. The plug block 19 is fixedly connected to the surface corresponding to the groove side wall and the groove bottom of the plug groove 20. A number of joint grouting pipes 14 extending in the vertical direction are provided between the joint gaps of two adjacent precast units.

[0058] Step 4: Use hoisting equipment to lift the end prefabricated units and the assembled prefabricated units onto the aforementioned prefabricated track 1, and use power equipment to push the end prefabricated units and the assembled prefabricated units horizontally to the construction position to complete the assembly between the end prefabricated units, the assembled prefabricated units, and the prefabricated pile wall; when the power equipment is working, the foundation grouting pipe 10 slides in contact with the prefabricated track 1, the side wall grouting pipe 12 slides in contact with the pile wall connection groove 8, the gap grouting pipe 11 slides in contact with the wall surface of the prefabricated pile wall 2, and the insertion grouting pipe 13 slides in contact with the insertion groove 20;

[0059] Step 5: Grouting is performed into each foundation grouting pipe 10, side wall grouting pipe 12, gap grouting pipe 11, plug grouting pipe 13, and joint grouting pipe 14. The grout flows out from the grout outlet 15 on each grouting pipe, filling the gaps between the end precast unit and the precast pile wall 2, the gaps between the end precast unit and the adjacent assembled precast unit, the gaps between two adjacent assembled precast units, and the gaps between each end precast unit, each assembled precast unit, and the precast track 1.

[0060] The foundation grouting pipe 10, side wall grouting pipe 12, gap grouting pipe 11, insert grouting pipe 13, and joint grouting pipe 14 all have the same diameter. In step three, during the prefabrication of the end prefabricated units and the assembly of the prefabricated units, the gap grouting pipes 11 on the same prefabricated unit are connected in advance through grouting branch pipes 17, and an insert pipe 18 is installed at one end of the grouting branch pipe 17. In step four, during assembly, the insert pipe 18 is inserted into the grouting branch pipe 17 on the adjacent side wall connecting block 7, and this operation is repeated to connect all the grouting branch pipes 17.

[0061] The gap grouting pipe 11, the insert grouting pipe 13, and the joint grouting pipe 14 all extend outside the top wall 4. In step five, before pouring the concrete grout, all the insert grouting pipes 13 and all the joint grouting pipes 14 are interconnected, and all the foundation grouting pipes 10 are interconnected. This is existing technology, and the specific method described in the above embodiments can be used, which will not be repeated here.

[0062] This invention divides the tunnel into multiple prefabricated units. These units can be prefabricated within the foundation pit and then assembled. During assembly, each unit is simply hoisted onto a prefabricated track by hoisting equipment. Guided by the track and the pile-wall connection groove, the units are smoothly and accurately assembled in their designated positions. Finally, grouting is injected into various grouting pipes to fill the gaps between the components. The prefabricated track itself becomes part of the tunnel without needing to be dismantled. The entire construction process is simple, shortens the construction period, and reduces the consumption of manpower, materials, and machinery.

[0063] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A prefabricated structure for an urban cut-and-cover tunnel, characterized in that, include: The precast pile wall has two sides arranged in parallel and spaced apart. The precast pile wall part is buried in the ground. The length direction of the precast pile wall is defined as the front-to-back direction, and the thickness direction is defined as the left-to-right direction. The two sides of the precast pile wall have pile wall connection grooves extending in the front-to-back direction on the opposite wall surfaces. The precast track is located between two precast side walls and cast on the ground, extending in the front-to-back direction and arranged at least two tracks at intervals in the left-to-right direction. The precast unit includes two end precast units and at least two assembled precast units located between the two end precast units. Both the end precast units and the assembled precast units include a foundation, side walls integrally cast at both ends of the foundation, a top wall integrally cast on top of the side walls, and a central partition wall integrally cast between the top wall and the foundation. The foundation has a foundation connection groove that slides with a precast track. A foundation grouting pipe extending in the front-rear direction is fixedly connected to the bottom and sidewalls of the foundation connection groove. The foundation grouting pipe slides in contact with the precast track when the corresponding precast unit moves relative to the precast track. A sidewall connection block integrally cast on the side wall slides with the pile-wall connection groove. The sidewall connection block has corresponding sidewalls and bottoms of the pile-wall connection groove. All surfaces are fixedly connected with side wall grouting pipes extending in the front-to-back direction. The side wall grouting pipes are used to slide in contact with the pile wall connection groove. The side wall facing the precast pile wall is also provided with multiple gap grouting pipes extending in the vertical direction and spaced in the front-to-back direction. The gap grouting pipes slide in contact with the wall surface of the precast pile wall. In adjacent end precast units and assembled precast units, as well as in two adjacent assembled precast units, one precast unit is provided with an integrally cast plug-in block, and the other precast unit is provided with a plug-in groove that matches the plug-in block. Plug-in grouting pipes are fixedly connected to the surfaces of the plug-in block corresponding to the groove sidewall and groove bottom of the plug-in groove. Multiple joint grouting pipes extending in the vertical direction are provided between the joints of two adjacent precast units. The foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe and splice grouting pipe are all provided with multiple grout outlet holes in the circumference; In the front-to-back direction, adjacent two corresponding foundation grouting pipes and adjacent two corresponding side wall grouting pipes are connected to each other through connectors. The grouting pipe is embedded in the side wall connecting block, with the bottom end of the grouting pipe flush with the bottom surface of the foundation and the top end of the grouting pipe extending out of the top wall.

2. The prefabricated structure for urban open-cut tunnels according to claim 1, characterized in that, Each grouting pipe on the same side wall connection block is connected to a grouting branch pipe. One end of the grouting branch pipe is open, and the other end is coaxially connected to an insert pipe. The outer diameter of the insert pipe is smaller than the outer diameter of the grouting branch pipe. The insert pipe is used to connect with the grouting branch pipe on the adjacent side wall connection block to connect the grouting branch pipes.

3. The prefabricated structure for urban open-cut tunnels according to claim 1 or 2, characterized in that, The joint grouting pipes and plug-in grouting pipes on the same end prefabricated unit or the same assembled prefabricated unit are interconnected.

4. The prefabricated structure for urban open-cut tunnels according to claim 3, characterized in that, All end prefabricated units and all assembled prefabricated units have interconnected joint grouting pipes and plug-in grouting pipes.

5. The prefabricated structure for urban open-cut tunnels according to claim 1 or 2, characterized in that, The diameters of the foundation grouting pipes, side wall grouting pipes, gap grouting pipes, plug grouting pipes, and splice grouting pipes are all the same.

6. A construction method for urban open-cut tunnels, characterized in that, Includes the following steps: Step 1: Excavate the foundation pit; Step 2: Construct two precast pile walls in the foundation pit and pour a precast track between the precast pile walls; pile wall connection grooves extending in the front-to-back direction are provided on the opposite walls of the two precast pile walls. Step 3: Prefabricate the end prefabricated units and the assembly prefabricated units. Both end prefabricated units and assembly prefabricated units include a foundation, side walls integrally cast at both ends of the foundation, a top wall integrally cast on top of the side walls, and a central partition wall integrally cast between the top wall and the foundation. The foundation has a foundation connection groove that slides with the prefabricated track. A foundation grouting pipe extending in the front-to-back direction is fixedly connected to the bottom and sidewalls of the foundation connection groove. Side wall connection blocks integrally cast with the pile-wall connection groove are fixedly connected to the surfaces of the sidewalls and bottoms of the pile-wall connection groove. The wall is connected to a grouting pipe extending in the front-to-back direction; the side wall facing the precast pile wall is also provided with multiple gap grouting pipes extending in the vertical direction and spaced apart in the front-to-back direction; in adjacent end precast units and assembled precast units, as well as in two adjacent assembled precast units, one precast unit is provided with an integrally cast plug-in block, and the other precast unit is provided with a plug-in groove adapted to the plug-in block. Plug-in grouting pipes are fixedly connected to the surfaces of the plug-in block corresponding to the groove sidewall and groove bottom of the plug-in groove. Multiple joint grouting pipes extending in the vertical direction are provided between the joints of two adjacent precast units. Step 4: Use hoisting equipment to lift the end prefabricated units and the assembled prefabricated units onto the prefabricated track, and use power equipment to push the end prefabricated units and the assembled prefabricated units horizontally to the construction position to complete the assembly between the end prefabricated units, the assembled prefabricated units, and the prefabricated pile wall; when the power equipment is working, the foundation grouting pipe slides in contact with the prefabricated track, the side wall grouting pipe slides in contact with the pile wall connection groove, and the gap grouting pipe slides in contact with the wall surface of the prefabricated pile wall; Step 5: Grouting is performed into each foundation grouting pipe, side wall grouting pipe, gap grouting pipe, plug grouting pipe, and joint grouting pipe. The grout flows out from the grout outlet on each grouting pipe, filling the gaps between the end precast unit and the precast pile wall, the gaps between the end precast unit and the adjacent assembled precast unit, the gaps between two adjacent assembled precast units, and the gaps between each end precast unit, each assembled precast unit, and the precast track.

7. The construction method for urban open-cut tunnels according to claim 6, characterized in that, In step three, when prefabricating the prefabricated end units and assembling the prefabricated units, the grouting pipes of each gap on the same prefabricated unit are connected in advance through grouting branch pipes, and an insert pipe is set at one end of the grouting branch pipe; in step four, during assembly, the insert pipe is inserted into the grouting branch pipe on the adjacent side wall connecting block, and this operation is repeated to connect all the grouting branch pipes.

8. The construction method for urban open-cut tunnels according to claim 7, characterized in that, All the joint grouting pipes, splice grouting pipes, and interlocking grouting pipes extend outside the top wall. In step five, before pouring the concrete grout, all the splice grouting pipes and interlocking grouting pipes are connected to each other, and all the foundation grouting pipes are connected to each other.

9. The construction method for urban open-cut tunnels according to any one of claims 6-8, characterized in that, The diameters of the foundation grouting pipes, side wall grouting pipes, gap grouting pipes, plug grouting pipes, and splice grouting pipes are all the same.

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