A three-layer superimposed support structure for soft rock tunnel and a construction method thereof

Abstract

The application discloses a three-layer superimposed supporting structure for soft rock tunnels and a construction method thereof, and relates to the technical field of tunnel supporting structure construction, which comprises, from outside to inside, a pipe curtain steel pipe, a ring-shaped steel arch structure and a steel reinforcement framework structure arranged in concentric circles, and further comprises a positioning and mounting assembly; the ring-shaped steel arch structure is combined and mounted in combination with the positioning and mounting assembly; the ring-shaped steel arch structure is formed into a complete circular ring structure by being spliced and combined by a plurality of steel arch assembly bodies; a penetrating pipe is arranged and mounted on the outer ring of the steel arch assembly body; the pipe curtain steel pipe is inserted into a tunnel wall after being positioned by the penetrating pipe; the steel reinforcement framework structure is arranged on the inner side of the ring-shaped steel arch structure; and cast-in-situ concrete is arranged between the pipe curtain steel pipe, the ring-shaped steel arch structure and the steel reinforcement framework structure; the ring-shaped steel arch structure is spliced and mounted through the positioning and mounting assembly, and the penetrating pipe is arranged, so that the installation precision and efficiency of the pipe curtain steel pipe are improved, and the supporting performance of the overall supporting system is further improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel support structure construction technology, specifically a three-layer composite support structure for soft rock tunnels and its construction method. Background Technology

[0002] With the continuous advancement of transportation infrastructure construction and urban underground space development in my country, tunnel engineering is gradually developing towards deep burial, large span, ultra-long length, and complex geological conditions. More and more tunnel projects need to traverse adverse geological sections such as high-stress soft rock, fractured zones, water-rich karst, and strongly weathered strata, which places higher demands on the bearing capacity, deformation adaptability, construction efficiency, and long-term service performance of soft rock tunnel lining structures.

[0003] Existing support methods for soft rock tunnels involve complex construction procedures and have weak overall integrity. Traditional advanced support methods (small guide pipes, pipe roofs) lack sufficient reinforcement capacity, and composite lining structures have poor water-stopping effects, making them susceptible to erosion by groundwater. In some deeply buried, high-stress soft rock strata, existing support systems are insufficient in pressure absorption and cannot effectively prevent large deformation disasters in soft rock, easily leading to safety accidents such as lining structure collapse and damage to personnel and equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a three-layer composite support structure for soft rock tunnels and its construction method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A three-layer composite support structure for soft rock tunnels includes concentrically arranged pipe curtain steel pipes, an annular steel arch structure, and a steel reinforcement skeleton structure. The pipe curtain steel pipes are driven into the tunnel wall along the tunnel's longitudinal direction. Installation slots are provided at the tunnel ends, and positioning installation components are installed at the center of each installation slot. The annular steel arch structure is assembled with the positioning installation components. The annular steel arch structure is formed by splicing multiple steel arch assemblies to form a complete circular structure. Inserted pipes are distributed and installed on the outer ring of the steel arch assemblies. The inserted pipes are fixedly installed on the outer ring of the steel arch assemblies. The pipe curtain steel pipes are inserted into the tunnel wall after being positioned by the inserted pipes. The steel reinforcement skeleton structure is arranged inside the annular steel arch structure. Cast-in-place concrete is placed between the pipe curtain steel pipes, the annular steel arch structure, and the steel reinforcement skeleton structure to enclose the pipe curtain steel pipes, the annular steel arch structure, and the steel reinforcement skeleton structure to form a whole.

[0006] As a further embodiment of the present invention: the cross-section of the steel arch frame assembly is an "I" shaped structure, the outer ring of the steel arch frame assembly is provided with an outer lining ring, the inner ring of the steel arch frame assembly is provided with an inner lining ring, the two ends of the outer lining ring are respectively provided with an outer lining mating groove and an outer lining protrusion, the two ends of the inner lining ring are respectively provided with an inner lining mating groove and an inner lining protrusion, and multiple steel arch frame assemblies are combined and spliced ​​to form a complete ring-shaped steel arch frame structure through the outer lining mating groove, outer lining protrusion and inner lining mating groove, inner lining protrusion.

[0007] As a further embodiment of the present invention: the two ends of the steel arch frame assembly are respectively provided with a combination groove and a combination mating plate, and adjacent steel arch frame assemblies are fixedly connected by the combination groove, the combination mating plate and the fixing bolts.

[0008] As a further embodiment of the present invention: a second connector is provided between adjacent insertion tubes, and the insertion tubes combined with the second connector are installed in a ring shape on the outside of the steel arch frame assembly to form a ring-shaped insertion tube structure. A first connector is provided on the side of the insertion tube facing the steel arch frame assembly, and the insertion tube abuts against the outside of the steel arch frame assembly through the first connector.

[0009] As a further embodiment of the present invention: multiple interpenetrating tubes are connected by connector two to form a single structure. The annular interpenetrating tube structure is formed by combining and splicing multiple single structures. The connector two at both ends of the single structure is provided with splicing stepped grooves. Adjacent single structures are combined and spliced ​​by splicing stepped grooves.

[0010] As a further embodiment of the present invention: the width of the outer liner ring is greater than the width of the inner liner ring, a connecting bolt is provided between the outer liner ring and the splicing stepped groove, the splicing stepped grooves between adjacent single structures are locked by the connecting bolt after docking, and the single structure is fixedly connected to the outer liner ring by the connecting bolt, and a positioning sleeve is sleeved on the outside of the connecting bolt.

[0011] As a further embodiment of the present invention: the steel reinforcement skeleton structure includes outer main bars, inner main bars, longitudinal bars, and hook bars. The inner main bars and outer main bars are arranged in concentric circles. Two sets of inner and outer main bars are arranged parallel to each other along the longitudinal direction of the tunnel. Longitudinal bars are welded between the two sets of outer main bars and the two sets of inner main bars. Hook bars are installed at the intersection of the longitudinal bars with the outer and inner main bars. Steel reinforcement skeleton connectors are provided on the inner side of the outer main bars and the steel arch frame assembly. The steel reinforcement skeleton connectors are welded to the outer main bars and the steel arch frame assembly respectively.

[0012] As a further embodiment of the present invention: the positioning and installation assembly includes a central rod disposed at the center of the tunnel in the longitudinal direction, a central sleeve disposed on the central rod, a plurality of connecting plates distributed on the central sleeve, an adjusting frame disposed at the end of the connecting plate, a support wheel disposed at the end of the adjusting frame, and the end of the support wheel abutting against the inner edge of the steel arch frame assembly.

[0013] A construction method for a three-layer composite support structure for soft rock tunnels includes the following steps: Step 1: First, an installation slot is opened at the tunnel end, and positioning installation components are set along the installation slot and the tunnel depth direction; Step 2: The steel arch frame assembly is assembled by combining the positioning installation components, so that the steel arch frame assembly is centrally positioned and installed; Step 3: Insert pipes are installed using the assembled annular steel arch frame assembly, and multiple insert pipes are wrapped and arranged on the outside of the steel arch frame assembly for fixed installation; Step 4: Pipe curtain steel pipes are driven into the tunnel wall sequentially through the insert pipes. After all pipe curtain steel pipes are installed, the steel reinforcement skeleton structure is assembled and placed inside the annular steel arch frame structure, and finally the positioning installation components are disassembled; Step 5: Cast-in-place concrete is poured between the steel reinforcement skeleton structure, the annular steel arch frame structure, and the pipe curtain steel pipes; the steel reinforcement skeleton structure, the annular steel arch frame structure, and the pipe curtain steel pipes are wrapped together to form a whole.

[0014] Compared with the prior art, the beneficial effects of the present invention are: (1) Multiple steel arch frame assemblies are spliced ​​together end to end to form a ring structure. The size of the steel arch frame assembly can be flexibly customized according to the tunnel size. When the size of the steel arch frame assembly is small, the assembly difficulty is low and the number of assemblies can be reduced. When the size of the steel arch frame assembly is large, the assembly difficulty increases at the same time, and the number of assemblies can be increased. That is, multiple steel arch frame assemblies are set. The ends of adjacent steel arch frame assemblies are respectively provided with outer lining docking groove, inner lining docking groove, outer lining protrusion, and inner lining protrusion. With the cooperation of positioning and installation components, the steel arch frame assembly is spliced ​​together.

[0015] (2) The pipe curtain steel pipe forms the outermost support structure. Therefore, it is necessary to ensure the installation accuracy of the pipe curtain steel pipe. By setting the insertion pipe on the outside of the steel arch frame assembly, the pipe curtain steel pipe is installed through the insertion pipe in sequence, thereby improving the installation efficiency and installation accuracy of the pipe curtain steel pipe.

[0016] (3) Pipe curtain steel pipes are driven into the tunnel wall sequentially through the insertion pipes. The pipe curtain steel pipes support and position the inner annular steel arch structure, reducing the pressure of the annular steel arch structure on the positioning and installation components. Then, the positioning and installation components are used to position and install the steel reinforcement skeleton structure. It should be noted that if the overall size of the steel reinforcement skeleton structure is small, it can be prefabricated directly. Finally, the steel reinforcement skeleton structure and the annular steel arch structure are assembled and installed by hoisting. If the overall size of the steel reinforcement skeleton structure is large and prefabrication is not possible, the outer main reinforcement, inner main reinforcement, and longitudinal reinforcement are positioned and installed sequentially using the positioning and installation components. Finally, the hook reinforcement is installed and connected to the inner side of the steel arch assembly by welding through the steel reinforcement skeleton connectors, thereby completing the overall installation of the steel reinforcement skeleton structure.

[0017] (4) The inner ring of the steel arch frame assembly is supported by the pre-set adjustment frame and support wheel. Specifically, it is supported on the inner side of the outer lining ring. When the steel arch frame assembly is spliced ​​in sequence, the steel arch frame assembly is supported by the connecting plate and adjustment frame, thereby realizing the positioning support installation of the steel arch frame assembly, which facilitates the subsequent installation of the insert pipe and the outer pipe curtain steel pipe and the inner steel reinforcement skeleton structure. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the arrangement between the invention and the tunnel.

[0019] Figure 2 This is a schematic diagram of the overall structure of the present invention.

[0020] Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle.

[0021] Figure 4 This is a schematic diagram of the annular steel arch frame structure in this invention.

[0022] Figure 5 for Figure 4 Enlarged structural diagram at point B.

[0023] Figure 6 for Figure 4 Enlarged structural diagram at point C.

[0024] Figure 7 for Figure 4 Enlarged structural diagram at point D.

[0025] Figure 8 This is a schematic diagram of the steel reinforcement skeleton structure in this invention.

[0026] Figure 9 This is a schematic diagram illustrating the cooperation between the steel arch frame connector and the positioning and installation assembly in this invention.

[0027] In the diagram: 01. Installation slot; 1. Pipe curtain steel pipe; 2. Annular steel arch frame structure; 20. Through pipe; 21. Connector 1; 22. Steel arch frame assembly; 220. Outer lining ring; 221. Outer lining butt groove; 222. Inner lining ring; 223. Inner lining butt groove; 224. Combined groove; 225. Inner lining protrusion; 226. Outer lining protrusion; 227. Combined mating plate; 23. Connector 2; 230. Splicing stepped groove; 24. Positioning sleeve; 25. Connecting bolt; 3. Reinforcing steel skeleton structure; 31. Outer main reinforcement; 32. Longitudinal reinforcement; 33. Hook reinforcement; 34. Reinforcing steel skeleton connector; 35. Inner main reinforcement; 4. Cast-in-place concrete; 5. Positioning and installation components; 50. Center sleeve; 51. Center rod; 52. Connecting plate; 53. Adjusting frame; 54. Support wheel. Detailed Implementation

[0028] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "upper", "lower", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] Furthermore, the terms "a" and "two" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "a" or "two" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0032] like Figure 1 , Figure 2 , Figure 3As shown, a three-layer composite support structure for soft rock tunnels includes concentrically arranged pipe curtain steel pipes 1, annular steel arch frame structure 2, and steel reinforcement skeleton structure 3 from the outside to the inside. The pipe curtain steel pipes 1 are driven into the tunnel wall along the tunnel's longitudinal direction. An installation slot 01 is provided at the tunnel end, and a positioning installation component 5 is provided at the center of the installation slot 01. The annular steel arch frame structure 2 is assembled and installed in conjunction with the positioning installation component 5. The annular steel arch frame structure 2 is formed by splicing together multiple steel arch frame assemblies 22. The steel arch frame assembly 22 has a circular ring structure. The outer ring of the steel arch frame assembly 22 is equipped with through-tubes 20. The through-tubes 20 are fixedly installed on the outer ring of the steel arch frame assembly 22. The pipe curtain steel pipe 1 is inserted into the tunnel wall after being positioned by the through-tubes 20. The steel reinforcement skeleton structure 3 is arranged inside the ring steel arch frame structure 2. Cast-in-place concrete 4 is set between the pipe curtain steel pipe 1, the ring steel arch frame structure 2 and the steel reinforcement skeleton structure 3 to wrap the pipe curtain steel pipe 1, the ring steel arch frame structure 2 and the steel reinforcement skeleton structure 3 to form a whole.

[0033] Specifically, firstly, installation slot 01 is set at the end of the tunnel. Then, the center point of the tunnel depth is located using installation slot 01. Positioning installation component 5 is set at this center point. After the positioning installation component 5 is installed, the ring-shaped steel arch structure 2, the pipe curtain steel pipe 1, and the steel reinforcement skeleton structure 3 are installed in sequence to form a three-layer composite support structure. Finally, the positioning installation component 5 is removed, and cast-in-place concrete 4 is poured into the three-layer composite support structure to wrap the ring-shaped steel arch structure 2, the pipe curtain steel pipe 1, and the steel reinforcement skeleton structure 3 to form an integral support structure.

[0034] Furthermore, such as Figures 4-7 As shown, the cross-section of the steel arch frame assembly 22 is an "I" shaped structure. The outer ring of the steel arch frame assembly 22 is provided with an outer lining ring 220, and the inner ring of the steel arch frame assembly 22 is provided with an inner lining ring 222. The two ends of the outer lining ring 220 are respectively provided with an outer lining mating groove 221 and an outer lining protrusion 226. The two ends of the inner lining ring 222 are respectively provided with an inner lining mating groove 223 and an inner lining protrusion 225. Multiple steel arch frame assemblies 22 are combined and spliced ​​together through the outer lining mating groove 221, the outer lining protrusion 226, the inner lining mating groove 223, and the inner lining protrusion 225 to form a complete ring-shaped steel arch frame structure 2.

[0035] Specifically, multiple steel arch frame assemblies 22 are spliced ​​end to end to form a ring structure. The size of the steel arch frame assembly 22 can be flexibly customized according to the tunnel size. When the size of the steel arch frame assembly 22 is small, the assembly difficulty is lower, and the number of assemblies can be reduced. When the size of the steel arch frame assembly 22 is large, the assembly difficulty increases, and the number of assemblies can be increased, that is, multiple steel arch frame assemblies 22 are set. The ends of adjacent steel arch frame assemblies 22 are respectively provided with outer lining docking grooves 221, inner lining docking grooves 223, outer lining protrusions 226, and inner lining protrusions 225. With the cooperation of the positioning and installation components 5, the steel arch frame assembly 22 can be assembled and spliced.

[0036] Furthermore, such as Figure 6 , Figure 7 As shown, the two ends of the steel arch frame assembly 22 are respectively provided with a combination groove 224 and a combination mating plate 227. Adjacent steel arch frame assemblies 22 are fixedly connected by the combination groove 224, the combination mating plate 227 and the fixing bolts.

[0037] Specifically, the steel arch frame assemblies 22 are fixedly connected through the combination grooves 224 and the combination mating plates 227 to ensure stability during the splicing process.

[0038] Furthermore, such as Figure 3 , Figure 4 As shown, a second connector 23 is provided between adjacent insertion tubes 20. The insertion tubes 20 and the second connector 23 are combined and installed in a ring shape on the outside of the steel arch frame assembly 22 to form a ring-shaped insertion tube 20 structure. A first connector 21 is provided on the side of the insertion tube 20 facing the steel arch frame assembly 22. The insertion tube 20 abuts against the outside of the steel arch frame assembly 22 through the first connector 21.

[0039] Specifically, the pipe curtain steel pipe 1 forms the outermost support structure. Therefore, it is necessary to ensure the installation accuracy of the pipe curtain steel pipe 1. By setting the insertion pipe 20 on the outside of the steel arch frame assembly 22, the pipe curtain steel pipe 1 is installed through the insertion pipe 20 in sequence, thereby improving the installation efficiency and installation accuracy of the pipe curtain steel pipe 1.

[0040] Furthermore, such as Figure 5 As shown, multiple insertion tubes 20 form a single structure through connector 23. The annular insertion tube 20 structure is formed by combining and splicing multiple single structures. The connector 23 at both ends of the single structure is provided with splicing stepped grooves 230. Adjacent single structures are combined and spliced ​​through splicing stepped grooves 230.

[0041] Specifically, the insert pipes 20 are connected by connectors 23, which are relatively thin. Multiple insert pipes 20 are combined to form a single structure, which facilitates handling and transportation, and also allows for quick assembly to form a ring structure that wraps around the outside of the ring-shaped steel arch structure 2. Connectors 23 between adjacent single structures are provided with stepped splicing grooves 230, which are then joined together during assembly.

[0042] Furthermore, such as Figure 5 , Figure 6 As shown, the width of the outer liner ring 220 is greater than the width of the inner liner ring 222. A connecting bolt 25 is provided between the outer liner ring 220 and the splicing stepped groove 230. After the splicing stepped grooves 230 between adjacent single structures are connected, they are locked by the connecting bolt 25. The single structure is fixedly connected to the outer liner ring 220 by the connecting bolt 25. A positioning sleeve 24 is sleeved on the outside of the connecting bolt 25.

[0043] Specifically, in order to facilitate the splicing and installation of the insertion tube 20, the outer liner ring 220 of the steel arch frame assembly 22 is wider than the inner liner ring 222. The extra dimension of the outer liner ring 220 can be used for the fixed installation between the insertion tube 20 and the outer liner ring 220. After the splicing of the individual structures of the insertion tube 20, the splicing stepped groove 230 is connected by connecting bolts 25, and the connecting bolts 25 are used to fix the outer liner ring 220.

[0044] The advantage of this installation method is that it eliminates the need for prefabrication of the entire annular perforated pipe 20 structure and avoids the overall hoisting step, thus reducing the installation difficulty of the individual perforated pipe 20 structure. During installation, the individual structure is first placed on the outside of the steel arch frame assembly 22, and then fixed to the outer lining ring 220 of the steel arch frame assembly 22 by means of the splicing stepped groove 230 and connecting bolts 25, ultimately achieving a complete annular perforated pipe 20 covering installation.

[0045] Furthermore, such as Figure 1 , Figure 8 As shown, the steel reinforcement skeleton structure 3 includes outer main reinforcement 31, inner main reinforcement 35, longitudinal reinforcement 32, and hook reinforcement 33. The inner main reinforcement 35 and the outer main reinforcement 31 are arranged in concentric circles. Two sets of inner main reinforcement 35 and outer main reinforcement 31 are arranged parallel to each other along the longitudinal direction of the tunnel. Longitudinal reinforcement 32 is welded between the two sets of outer main reinforcement 31 and the two sets of inner main reinforcement 35. Hook reinforcement 33 is installed at the intersection of the longitudinal reinforcement 32 with the outer main reinforcement 31 and the inner main reinforcement 35. Steel reinforcement skeleton connectors 34 are provided on the inner side of the outer main reinforcement 31 and the steel arch frame assembly 22. The steel reinforcement skeleton connectors 34 are welded to the outer main reinforcement 31 and the steel arch frame assembly 22 respectively.

[0046] Specifically, after the insertion pipe 20 is installed, the pipe curtain steel pipe 1 is driven into the tunnel wall sequentially through the insertion pipe 20. The pipe curtain steel pipe 1 supports and positions the inner annular steel arch structure 2, reducing the pressure of the annular steel arch structure 2 on the positioning and installation components 5. Then, the positioning and installation components 5 are used to position and install the steel reinforcement skeleton structure 3. It should be noted that if the overall size of the steel reinforcement skeleton structure 3 is small, it can be prefabricated and then assembled with the annular steel arch structure 2 by hoisting. If the overall size of the steel reinforcement skeleton structure 3 is large and prefabrication is not possible, the outer main reinforcement 31, inner main reinforcement 35, and longitudinal reinforcement 32 are positioned and installed sequentially using the positioning and installation components 5. Finally, the hook reinforcement 33 is installed and then welded to the inner side of the steel arch assembly 22 through the steel reinforcement skeleton connector 34, thus completing the overall installation of the steel reinforcement skeleton structure 3.

[0047] Furthermore, such as Figure 1 , Figure 9 As shown, the positioning and installation assembly 5 includes a central rod 51 located at the center of the tunnel in the longitudinal direction. A central sleeve 50 is provided on the central rod 51. Multiple sets of connecting plates 52 are distributed on the central sleeve 50. An adjustment frame 53 is provided at the end of the connecting plate 52. A support wheel 54 is provided at the end of the adjustment frame 53. The end of the support wheel 54 abuts against the inner edge of the steel arch frame assembly 22.

[0048] Specifically, during the assembly and installation of the steel arch frame assembly 22, the inner ring of the steel arch frame assembly 22 is supported by the pre-set adjustment frame 53 and support wheel 54, specifically supported on the inner side of the outer liner ring 220. When the steel arch frame assembly 22 is spliced ​​sequentially, the steel arch frame assembly 22 is supported by the connecting plate 52 and adjustment frame 53, thereby realizing the positioning and support installation of the steel arch frame assembly 22, which facilitates the subsequent installation of the insert pipe 20, the outer pipe curtain steel pipe 1, and the inner steel reinforcement skeleton structure 3.

[0049] A construction method for a three-layer composite support structure for soft rock tunnels includes the following steps: Step 1: First, an installation slot 01 is opened at the tunnel end, and a positioning installation component 5 is set along the installation slot 01 and the tunnel depth direction; Step 2: Combine the positioning installation component 5 to assemble the steel arch frame assembly 22, so that the steel arch frame assembly 22 is centrally positioned and installed; Step 3: Install the inserted pipes 20 using the assembled annular steel arch frame assembly 22, wrapping multiple inserted pipes 20 around the outside of the steel arch frame assembly 22 and fixing them in place; Step 4: Drive the pipe curtain steel pipes 1 into the tunnel wall sequentially through the inserted pipes 20. After all the pipe curtain steel pipes 1 are installed, assemble and install the steel reinforcement skeleton structure 3 and place it inside the annular steel arch frame structure 2, and finally disassemble the positioning installation component 5; Step 5: Set up cast-in-place concrete 4 between the steel reinforcement skeleton structure 3, the annular steel arch frame structure 2 and the pipe curtain steel pipes 1; wrap the steel reinforcement skeleton structure 3, the annular steel arch frame structure 2 and the pipe curtain steel pipes 1 to form a whole.

[0050] The working principle of this invention embodiment is as follows: like Figures 1-9As shown, firstly, installation slot 01 is set at the end of the tunnel. Using installation slot 01, the center point of the tunnel's depth is located, and positioning installation component 5 is installed at this center point. After the positioning installation component 5 is installed, the annular steel arch structure 2, the pipe curtain steel pipe 1, and the steel reinforcement skeleton structure 3 are installed sequentially to form a three-layer composite support structure. Finally, the positioning installation component 5 is removed, and cast-in-place concrete 4 is poured onto the three-layer composite support structure to enclose the annular steel arch structure 2, the pipe curtain steel pipe 1, and the steel reinforcement skeleton structure 3, forming an integral support structure. Multiple steel arch assembly units 22 are spliced ​​end-to-end to form a ring structure. The dimensions of the steel arch assembly unit 22 can be flexibly customized according to the tunnel dimensions. When the size of the steel arch frame assembly 22 is small, the assembly difficulty is lower, and the number of assemblies can be reduced. When the size of the steel arch frame assembly 22 is large, the assembly difficulty increases, and the number of assemblies can be increased, i.e., multiple steel arch frame assemblies 22 are set. The ends of adjacent steel arch frame assemblies 22 are respectively provided with outer lining docking grooves 221, inner lining docking grooves 223, outer lining protrusions 226, and inner lining protrusions 225. With the cooperation of the positioning and installation components 5, the steel arch frame assemblies 22 are assembled and spliced. The pipe curtain steel pipes 1 form the outermost support structure, so it is necessary to ensure the installation accuracy of the pipe curtain steel pipes 1. By setting the through pipes 20 on the outside of the steel arch frame assembly 22, the pipe curtain steel pipes 1 are installed sequentially through the through pipes 20, thereby improving the installation efficiency and installation accuracy of the pipe curtain steel pipes 1. The insert pipes 20 are connected by connectors 23, which are relatively thin. Multiple insert pipes 20 are combined to form a single structure, which facilitates handling and transportation, and also allows for quick assembly to form a ring structure that wraps around the outside of the ring-shaped steel arch frame structure 2. Connectors 23 between adjacent single structures are provided with stepped splicing grooves 230, which are then spliced ​​together during assembly. To facilitate the splicing and installation of the insert pipes 20, the outer lining ring 220 of the steel arch frame assembly 22 is wider than the inner lining ring 222. The extra dimension of the outer lining ring 220 can be used for the fixed installation between the insert pipes 20 and the outer lining ring 220. After splicing, the stepped splicing grooves 230 between the individual insert pipe structures are connected by connecting bolts 25, and then fixed to the outer lining ring 220 using these connecting bolts 25. After the insertion pipe 20 is installed, the pipe curtain steel pipes 1 are driven into the tunnel wall sequentially through the insertion pipe 20. The pipe curtain steel pipes 1 support and position the inner annular steel arch structure 2, reducing the pressure of the annular steel arch structure 2 on the positioning and installation components 5. Then, the positioning and installation components 5 are used to position and install the steel reinforcement skeleton structure 3. It should be noted that if the overall size of the steel reinforcement skeleton structure 3 is small, it can be prefabricated directly. Finally, the steel reinforcement skeleton structure 3 and the annular steel arch structure 2 are assembled and installed by hoisting.If the overall size of the steel reinforcement frame structure 3 is too large to be prefabricated, the outer main reinforcement 31, inner main reinforcement 35, and longitudinal reinforcement 32 are sequentially positioned and installed using the positioning and installation components 5. Finally, the hook reinforcement 33 is distributed and installed. The steel reinforcement frame is then welded to the inner side of the steel arch frame assembly 22 via the steel reinforcement frame connector 34, thus completing the overall installation of the steel reinforcement frame structure 3. During assembly, the inner ring of the steel arch frame assembly 22 is supported by pre-set adjustment frames 53 and support wheels 54, specifically on the inner side of the outer lining ring 220. As the steel arch frame assembly 22 is sequentially spliced, it is supported by connecting plates 52 and adjustment frames 53, thus achieving the positioning and support installation of the steel arch frame assembly 22. This facilitates the subsequent installation of the insert pipe 20, the outer pipe curtain steel pipe 1, and the inner steel reinforcement frame structure 3.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A three-layer composite support structure for soft rock tunnels, characterized in that, It includes a pipe curtain steel pipe (1) arranged in concentric circles from the outside to the inside, a ring steel arch frame structure (2) and a steel reinforcement skeleton structure (3). The pipe curtain steel pipe (1) is driven into the tunnel wall along the longitudinal direction of the tunnel. An installation slot (01) is provided at the end of the tunnel. A positioning installation component (5) is provided at the center of the installation slot (01). The ring steel arch frame structure (2) is combined with the positioning installation component (5) for installation. The annular steel arch frame structure (2) is formed by splicing and assembling multiple steel arch frame assemblies (22) to form a complete annular structure. The outer ring of the steel arch frame assembly (22) is equipped with through pipes (20). The through pipes (20) are fixedly installed on the outer ring of the steel arch frame assembly (22). The pipe curtain steel pipe (1) is inserted into the tunnel wall after being positioned by the through pipes (20). The steel reinforcement skeleton structure (3) is arranged on the inner side of the annular steel arch frame structure (2). Cast-in-place concrete (4) is provided between the pipe curtain steel pipe (1), the annular steel arch frame structure (2) and the steel reinforcement skeleton structure (3) to wrap the pipe curtain steel pipe (1), the annular steel arch frame structure (2) and the steel reinforcement skeleton structure (3) to form a whole.

2. The three-layer composite support structure for soft rock tunnels according to claim 1, characterized in that, The cross-section of the steel arch frame assembly (22) is an "I" shaped structure. The outer ring of the steel arch frame assembly (22) is provided with an outer lining ring (220), and the inner ring of the steel arch frame assembly (22) is provided with an inner lining ring (222). The two ends of the outer lining ring (220) are respectively provided with an outer lining docking groove (221) and an outer lining protrusion (226). The two ends of the inner lining ring (222) are respectively provided with an inner lining docking groove (223) and an inner lining protrusion (225). Multiple steel arch frame assemblies (22) are combined and spliced ​​to form a complete ring-shaped steel arch frame structure (2) through the outer lining docking groove (221), the outer lining protrusion (226), the inner lining docking groove (223), and the inner lining protrusion (225).

3. The three-layer composite support structure for soft rock tunnels according to claim 2, characterized in that, The two ends of the steel arch frame assembly (22) are respectively provided with a combination groove (224) and a combination mating plate (227). The adjacent steel arch frame assemblies (22) are fixedly connected by the combination groove (224), the combination mating plate (227) and the fixing bolts.

4. The three-layer composite support structure for soft rock tunnels according to claim 3, characterized in that, A second connector (23) is provided between adjacent insertion tubes (20). The insertion tubes (20) and the second connector (23) are combined and installed in a ring shape on the outside of the steel arch frame assembly (22) to form a ring-shaped insertion tube (20) structure. A first connector (21) is provided on the side of the insertion tube (20) facing the steel arch frame assembly (22). The insertion tube (20) abuts against the outside of the steel arch frame assembly (22) through the first connector (21).

5. A three-layer composite support structure for soft rock tunnels according to claim 4, characterized in that, Multiple insertion tubes (20) are connected by connector two (23) to form a single structure. The annular insertion tube (20) structure is formed by combining and splicing multiple single structures. The connector two (23) at both ends of the single structure is provided with splicing stepped grooves (230). Adjacent single structures are combined and spliced ​​by splicing stepped grooves (230).

6. A three-layer composite support structure for soft rock tunnels according to claim 5, characterized in that, The width of the outer liner ring (220) is greater than the width of the inner liner ring (222). A connecting bolt (25) is provided between the outer liner ring (220) and the splicing stepped groove (230). After the splicing stepped groove (230) between adjacent single structures is connected, it is locked by the connecting bolt (25). The single structure is fixedly connected to the outer liner ring (220) by the connecting bolt (25). A positioning sleeve (24) is sleeved on the outside of the connecting bolt (25).

7. The three-layer composite support structure for soft rock tunnels according to claim 1, characterized in that, The steel reinforcement skeleton structure (3) includes an outer main reinforcement (31), an inner main reinforcement (35), a longitudinal reinforcement (32), and a hook reinforcement (33). The inner main reinforcement (35) and the outer main reinforcement (31) are arranged in concentric circles. The inner main reinforcement (35) and the outer main reinforcement (31) are arranged in two sets parallel to each other along the tunnel depth direction. The two sets of outer main reinforcement (31) and the two sets of inner main reinforcement (35) are welded with longitudinal reinforcement (32). The intersection of the longitudinal reinforcement (32) with the outer main reinforcement (31) and the inner main reinforcement (35) is equipped with hook reinforcement (33). The outer main reinforcement (31) and the inner side of the steel arch frame assembly (22) are provided with steel reinforcement skeleton connectors (34). The steel reinforcement skeleton connectors (34) are welded to the outer main reinforcement (31) and the steel arch frame assembly (22) respectively.

8. The three-layer composite support structure for soft rock tunnels according to claim 1, characterized in that, The positioning and installation assembly (5) includes a central rod (51) located at the center of the tunnel in the longitudinal direction. A central sleeve (50) is provided on the central rod (51). Multiple sets of connecting plates (52) are distributed on the central sleeve (50). An adjustment frame (53) is provided at the end of the connecting plate (52). A support wheel (54) is provided at the end of the adjustment frame (53). The end of the support wheel (54) abuts against the inner edge of the steel arch frame assembly (22).

9. The construction method of the three-layer composite support structure for soft rock tunnels according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: First, open an installation slot (01) at the end of the tunnel, and set up the positioning installation component (5) along the installation slot (01) and the tunnel depth direction. Step 2: Combine the positioning and installation components (5) to assemble the steel arch frame assembly (22), so that the steel arch frame assembly (22) is centrally positioned and installed; Step 3: Install the insertion pipes (20) using the assembled annular steel arch frame assembly (22), wrap the multiple insertion pipes (20) around the outside of the steel arch frame assembly (22) and fix them in place; Step 4: Drive the pipe curtain steel pipes (1) into the tunnel wall in sequence through the insertion pipe (20). After the installation of all the pipe curtain steel pipes (1) is completed, assemble and install the steel reinforcement frame structure (3) and place it inside the annular steel arch frame structure (2). Finally, disassemble and install the positioning assembly (5). Step 5: Cast-in-place concrete (4) is installed between the steel reinforcement skeleton structure (3), the annular steel arch structure (2) and the pipe curtain steel pipe (1); the steel reinforcement skeleton structure (3), the annular steel arch structure (2) and the pipe curtain steel pipe (1) are wrapped together to form an integral whole.

Images