Bedding unsymmetrical pressure tunnel steel arch primary lining structure and construction method

Abstract

The invention provides a bedding unsymmetrical pressure tunnel steel arch primary lining structure and a construction method, and belongs to the technical field of tunnel primary linings, the bedding unsymmetrical pressure tunnel steel arch primary lining structure comprises a plurality of steel arch bodies, a first connecting unit and a second connecting unit, the plurality of steel arch bodies divide a tunnel wall into a plurality of supporting sections along the camber direction of the tunnel wall; steel arch bodies with the corresponding number are arranged in the supporting sections according to different bedding and bias effects in the supporting sections, when the number of the steel arch bodies of every two adjacent supporting sections is the same, the steel arch bodies are connected through first connecting units, and when the number of the steel arch bodies of every two adjacent supporting sections is different, the steel arch bodies of every two adjacent supporting sections are connected through second connecting units. The steel arch bodies are connected through the second connecting units, and therefore the supporting sections with the large bedding and bias effects can be reinforced and supported by arranging the multiple steel arch bodies.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel primary lining, and in particular relates to a primary lining structure of a layer-aligned biased tunnel steel arch frame and a construction method. Background Art

[0002] A bedding bias tunnel refers to a tunnel in which there are bedding and bias effects in the strata around the tunnel. During tunnel construction, the bedding and bias effects will cause redistribution and deformation of the strata. Therefore, the initial lining of a bedding bias tunnel will be more complicated in terms of the structure and number of steel arch frames than that of an ordinary tunnel.

[0003] The Chinese invention patent with the publication number "CN111425217A" discloses "a reusable assembled sleeve arch structure and its construction method". In this invention, at least three steel arch frames are connected by connecting steel bars, and each steel arch frame is connected to the sleeve arch base; the orifice pipe is arranged on the top of the steel arch frame; when using the sleeve arch structure, the orifice pipes are fixed one by one in the large pipe shed, and the three steel arch frames at the bottom play a role in fixing and supporting the large pipe shed through the orifice pipes. After the assembled sleeve arch structure is positioned, the pipe shed construction can be carried out quickly. The assembled pipe shed sleeve arch does not require high foundation bearing capacity. When encountering a biased tunnel opening with steep and undulating mountainous terrain and oblique terrain, the assembled sleeve arch structure provided by this solution can be used to achieve "zero" excavation of the side slope, thereby avoiding the safety hazard of the side slope and the back slope of the tunnel opening being too high. At the same time, it can also achieve environmental coordination and reflect the concept of green highway. However, when supporting the layer-biased tunnel, this invention only uses multiple steel arch frames connected by steel bars to strengthen the support of all places in the tunnel. In the layer-biased tunnel, only the places with large layer and bias effects require two or more steel arch frames for strengthened support. Therefore, the multiple steel arch frames of this invention do not play the due supporting role, resulting in a waste of steel arch frames.

[0004] Therefore, its shortcoming is that, during the construction of the bedding bias pressure tunnel, the invention cannot provide reinforced support only for places where the bedding and bias pressure effects are larger. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a primary lining structure and construction method of a steel arch frame in a bedding biased tunnel, which is used to solve the problem in the prior art that it is impossible to strengthen support only in places where the bedding and biased effects are large.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a primary lining structure of a steel arch frame of a layer-by-layer biased tunnel, the primary lining structure comprising: A plurality of steel arch frame bodies, which divide the tunnel wall into a plurality of support sections along the curvature direction of the tunnel wall, each support section corresponds to at least one steel arch frame body, and the entire tunnel wall is supported along the curvature direction by the steel arch frame bodies in all the support sections; A first connection unit, wherein the first connection unit includes a pad, and when the number of steel arch frame bodies of two adjacent support sections is the same, the steel arch frame bodies are connected by the pad; The second connecting unit includes an expansion component. When the number of steel arch frame bodies in two adjacent supporting sections is different, the steel arch frame bodies in the two adjacent supporting sections are connected by the expansion component. The expansion component is installed at the connection of the steel arch frame bodies with a smaller number in the two adjacent supporting sections to lengthen the length of the connection of the steel arch frame bodies along the axial direction of the tunnel.

[0007] As an optional solution, the steel arch frame body includes a waist plate, an upper wing plate, a lower wing plate and two end plates, and the waist plate, the upper wing plate and the lower wing plate are all arc-shaped plates; The upper wing plate is fixedly connected to one end of the waist plate close to the tunnel wall, and the lower wing plate is fixedly connected to one end of the waist plate away from the tunnel wall, and the upper wing plate and the lower wing plate are arranged opposite to each other; One end of the waist plate, the upper wing plate and the lower wing plate along the direction of the tunnel wall camber is located in the same plane and the plane is a first plane, and the other end of the waist plate, the upper wing plate and the lower wing plate along the direction of the tunnel wall camber is located in the same plane and the plane is a second plane, one of the end plates is fixed on the first plane, and the other end plate is fixed on the second plane; The end plates of the steel arch frame bodies in two adjacent support sections are fixedly connected via a pad or an expansion component.

[0008] As an optional solution, the arc length of the upper wing plate is greater than the arc length of the lower wing plate.

[0009] As an optional solution, the waist plate, the upper wing plate, and the lower wing plate are connected to form an I-beam, and there are arc-shaped grooves on the left and right sides of the waist plate; The expansion assembly includes two mounting members, one of which is mounted on the left end of the leftmost end plate in the support section, and the other is mounted on the right end of the rightmost end plate in the support section; The mounting parts each include a mounting plate, a first extending plate and a second extending plate, wherein the first extending plate and the second extending plate are fixedly connected to the same end surface of the mounting plate, and the first extending plate and the second extending plate are arranged in parallel; The first extended plate is fitted to the end of the end plate away from the waist plate, and the opposite end surfaces of the first extended plates on both sides are kept in contact; The second extending plate extends into the arc-shaped groove, and the second extending plate is attached to the end surface of the end plate away from the first extending plate; In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates of the steel arch frame bodies with fewer numbers in the support section fix the end plates of the steel arch frame bodies with more numbers in the support section.

[0010] As an optional solution, the primary lining structure further includes a first support rod, one end of which is detachably connected to the waist plate, and the other end of which is detachably connected to the mounting plate; The first support rod is arranged tilted.

[0011] As an optional solution, the primary lining structure further includes a plurality of second support rods; One end of the second support rod is fixedly connected to the upper wing plate, and the other end of the second support rod is fixedly connected to the lower wing plate.

[0012] As an optional solution, the steel arch frame bodies at both ends along the tunnel wall arch direction are fixedly connected to the tunnel bottom through end plates.

[0013] The present invention also provides a method for constructing a primary lining of a steel arch frame of a layer-biased tunnel, comprising the above-mentioned primary lining structure of a steel arch frame of a layer-biased tunnel. The primary lining construction method comprises: Preparation steps: Scan the mountain data of the entire tunnel to be excavated and perform numerical simulation of the eccentric load at various locations along the excavation path; Excavation steps: digging tunnels in the mountain; Testing steps: measuring the eccentric load of each supporting section of the tunnel wall in the tunnel; Steel arch frame body selection step: according to the range of the bias load of each supporting section of the tunnel wall, a steel arch frame body is selected from steel arch frame bodies that can withstand different loads; Construction steps: Different numbers of steel arch frame bodies are distributed according to the bias loads received by different support sections, and the steel arch frame bodies of each support section are fixedly connected through the first connecting unit or the second connecting unit to support the entire tunnel wall along its arch direction.

[0014] As an optional solution, in the steel arch frame body selection step, the force load of the single steel arch frame body selected is not less than the minimum bias load in each supporting segment.

[0015] As an optional solution, in the construction steps, when the support section requires multiple steel arch frame bodies to support it, the multiple steel arch frame bodies are arranged in parallel along the axial direction of the tunnel.

[0016] As described above, the primary lining structure and construction method of the steel arch frame of the layer-by-layer biased tunnel of the present invention have at least the following beneficial effects: 1. The present invention can set different numbers of steel arch frame bodies in each supporting section according to the different bedding and bias pressure effects of each supporting section in the tunnel, so that the supporting section with larger bedding and bias pressure effects can be strengthened by setting multiple steel arch frame bodies.

[0017] 2. In the present invention, when the number of steel arch frame bodies in two adjacent support sections is different, a mounting piece is inserted into the left end of the leftmost end plate on the steel arch frame body with a smaller number of bodies close to the steel arch frame body with a larger number of bodies, and a mounting piece is inserted into the right end of the rightmost end plate, and then the end plates of the steel arch frame bodies in the two adjacent support sections that are close to each other are fixedly connected by bolting or welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a schematic diagram showing the structure of the present invention when the number of steel arch frame bodies in two adjacent support sections is the same; Figure 3 It is a schematic diagram showing the structure of the present invention when the number of steel arch frame bodies in two adjacent support sections is different; Figure 4 Shown is an exploded view related to the mounting member of the present invention; Figure 5 Shown as the present invention Figure 4 A local enlarged view of point A in FIG. Figure 6 Shown is a schematic diagram of the structure related to the arc-shaped groove of the present invention; Figure 7 It is a schematic diagram showing the structure of the spandrel, haunch and foot of the present invention; Figure 8 Shown is a schematic structural diagram of the I-beam size identification of the present invention.

[0019] In the figure: 101, pad; 201, waist plate; 202, upper wing plate; 203, lower wing plate; 204, end plate; 301, arc-shaped groove; 302, mounting plate; 303, first extending plate; 304, second extending plate; 305, plug-in slot; 401, first support rod; 501, second support rod; 601, arch foot; 602, arch waist; 603, arch shoulder; 701. Soil pressure sensor. DETAILED DESCRIPTION

[0020] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0021] See also Figures 1 to 8 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0022] The following embodiments are only for illustration purposes and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0023] See also Figure 1 and Figure 2 The present invention provides a primary lining structure of a steel arch frame of a layer-by-layer biased tunnel, the primary lining structure comprising: A plurality of steel arch frame bodies, which divide the tunnel wall into a plurality of support sections along the curvature direction of the tunnel wall, each support section corresponds to at least one steel arch frame body, and the entire tunnel wall is supported along the curvature direction by the steel arch frame bodies in all the support sections; When a plurality of steel arch frame bodies correspond to one supporting section, the plurality of steel arch frame bodies are arranged in parallel along the axial direction of the tunnel; A first connection unit, wherein the first connection unit includes a pad 101. When the number of steel arch frame bodies of two adjacent support sections is the same, the steel arch frame bodies are connected by the pad 101; The second connecting unit includes an expansion component. When the number of steel arch frame bodies in two adjacent supporting sections is different, the steel arch frame bodies in the two adjacent supporting sections are connected by the expansion component. The expansion component is installed at the connection of the steel arch frame bodies with a smaller number in the two adjacent supporting sections to lengthen the length of the connection of the steel arch frame bodies along the axial direction of the tunnel.

[0024] In this embodiment, when the steel arch frame body is used to support the tunnel wall, the steel arch frame bodies between adjacent support sections are connected by pads 101 or expansion components to support the entire tunnel wall along its arch direction. The present invention can set different numbers of steel arch frame bodies according to the different bedding and bias effects of each support section in the tunnel, so that the support section with larger bedding and bias effects can be strengthened by setting multiple steel arch frame bodies.

[0025] See also Figure 2 The steel arch frame body includes a waist plate 201, an upper wing plate 202, a lower wing plate 203 and two end plates 204, and the waist plate 201, the upper wing plate 202 and the lower wing plate 203 are all arc-shaped plates; The upper wing plate 202 is fixedly connected to one end of the waist plate 201 close to the tunnel wall, and the lower wing plate 203 is fixedly connected to one end of the waist plate 201 away from the tunnel wall. The upper wing plate 202 and the lower wing plate 203 are arranged opposite to each other. One end of the waist plate 201, the upper wing plate 202 and the lower wing plate 203 along the tunnel wall camber direction is located in the same plane and the plane is a first plane, and the other end of the waist plate 201, the upper wing plate 202 and the lower wing plate 203 along the tunnel wall camber direction is located in the same plane and the plane is a second plane, one of the end plates 204 is fixed on the first plane, and the other end plate 204 is fixed on the second plane; The end plates 204 of the steel arch bodies in two adjacent support sections are fixedly connected by the pads 101 or the expansion components; The method of fixing and connecting the end plates 204 adjacent to the steel arch body is not limited here, and can be fixed and connected by bolts or welding.

[0026] In this embodiment, when the steel arch frame body is used to support the tunnel wall, the adjacent end plates 204 of the steel arch frame body between each adjacent support section are connected through the pad 101 or the expansion assembly to support the entire tunnel wall along its arch direction. The present invention can interconnect the steel arch frame bodies through the end plates 204 of the steel arch frame body in conjunction with the pad 101 or the expansion assembly, and the structural design is ingenious.

[0027] See also Figure 2 , the arc length of the upper wing plate 202 is greater than the arc length of the lower wing plate 203.

[0028] In this embodiment, when two adjacent steel arches installed in the tunnel are subjected to the pressure of the tunnel wall, a part of the forces received by the two adjacent end plates 204 will interact with each other. The steel arch body of the present invention is an arc-shaped structure, and the forces received by the two adjacent end plates 204 partially interact with each other to reduce the radial pressure of the tunnel wall on the steel arch body itself. See also Figures 3 to 6 The waist plate 201, the upper wing plate 202, and the lower wing plate 203 are connected to form an I-beam, and the left and right sides of the waist plate 201 are both provided with arc grooves 301; The expansion assembly includes two mounting members, one of which is mounted on the left end of the leftmost end plate 204 in the support section, and the other mounting member is mounted on the right end of the rightmost end plate 204 in the support section; The mounting parts all include a mounting plate 302, a first extending plate 303 and a second extending plate 304. The first extending plate 303 and the second extending plate 304 are fixedly connected to the same end surface of the mounting plate 302. The first extending plate 303 and the second extending plate 304 are arranged in parallel. A plug-in slot 305 is formed at the end surface of the first extending plate 303 relative to the second extending plate 304, at the second extending end relative to the end surface of the first extending plate 303 and at the end surface of the mounting plate 302 fixedly connected to the first extending plate 303 and the second extending plate 304. The two mounting members are respectively plugged into the end plates 204 with a smaller number in two adjacent support sections through the plug-in grooves 305. When the number of end plates 204 with a smaller number between two adjacent support sections is one, the two mounting members are plugged into the two sides of the end plates 204 along the axial direction of the tunnel. When the number of end plates 204 with a smaller number between two adjacent support sections is two or more, the two mounting members are respectively plugged into the side walls of the outermost end plates 204 along the axial direction of the tunnel. The first extended plate 303 is attached to one end of the end plate 204 away from the waist plate 201, and the opposite end surfaces of the first extended plates 303 on both sides are kept in contact; The second extending plate 304 extends into the arc groove 301, and the second extending plate 304 is attached to the end surface of the end plate 204 away from the first extending plate 303. The end surface of the second extending plate 304 extending into the arc groove 301 close to the waist plate 201 is attached to the waist plate 201, the end surface of the second extending plate 304 extending into the arc groove 301 close to the upper wing plate 202 is attached to the upper wing plate 202, and the end surface of the second extending plate 304 extending into the arc groove 301 close to the lower wing plate 203 is attached to the lower wing plate 203; In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates 204 of the steel arch frame bodies with fewer numbers in the support section fix the end plates 204 of the steel arch frame bodies with more numbers in the support section.

[0029] In this embodiment, when the number of steel arch frame bodies in two adjacent support segments is the same, the end plates 204 between the steel arch frame bodies in the two adjacent support segments are all bonded together through the pads 101, and then the steel arch frame bodies in the two adjacent support segments are fixedly connected by bolt connection or welding; When the number of steel arch frame bodies in two adjacent support sections is different, when there is one steel arch frame body with a smaller number, a mounting piece is inserted at the left and right ends of the end plate 204 on the steel arch frame body with a smaller number, which is close to the steel arch frame body with a larger number, respectively, and then the end plates 204 close to the steel arch frame bodies in the two adjacent support sections are fixedly connected by bolt connection or welding. When there are multiple steel arch frame bodies with a smaller number, a mounting piece is inserted at the left end of the end plate 204 on the left side of the steel arch frame body with a smaller number, and a mounting piece is inserted at the right end of the end plate 204 on the right side, and then the end plates 204 close to the steel arch frame bodies in the two adjacent support sections are fixedly connected by bolt connection or welding. The present invention can install different numbers of steel arch frame bodies for support according to the stress conditions of different support sections in the tunnel by inserting mounting pieces into the end plates 204 of the steel arch frame with a smaller number.

[0030] See also Figure 1 , Figure 3 and Figure 4 The primary lining structure further includes a first support rod 401, one end of the first support rod 401 is detachably connected to the waist plate 201, and the other end of the first support rod 401 is detachably connected to the mounting plate 302; The first support rod 401 is arranged tilted.

[0031] In this embodiment, when the number of steel arch frame bodies in two adjacent support sections is different, after the mounting piece is plugged into the end plate 204 of the steel arch frame body in the fewer support sections, one end of the first support rod 401 is fixedly connected to the waist plate 201 by bolts, and the other end of the first support rod 401 is fixedly connected to the mounting plate 302 by bolts, so that the first support rod 401 is obliquely supported on both sides of the waist plate 201 on the steel arch frame body. The present invention can provide enhanced support for the mounting piece plugged into the end plate 204 by obliquely supporting the first support rod 401 between the waist plate 201 and the mounting piece.

[0032] See also Figure 6 , the primary lining structure also includes a plurality of second support rods 501; The second support rod 501 is disposed in the arc-shaped groove 301 , one end of the second support rod 501 is fixedly connected to the upper wing plate 202 , and the other end of the second support rod 501 is fixedly connected to the lower wing plate 203 .

[0033] In this embodiment, the second support rod 501 is supported between the upper wing plate 202 and the lower wing plate 203. In the present invention, the second support rod 501 is supported between the upper wing plate 202 and the lower wing plate 203, so that the support between the upper wing plate 202 and the lower wing plate 203 can be strengthened.

[0034] See also Figures 1 to 3 The steel arch frame bodies at both ends along the tunnel wall arch direction are fixedly connected to the tunnel bottom through end plates 204.

[0035] In this embodiment, when the steel arch frame body at both ends along the tunnel wall arch direction is installed with the tunnel bottom, the end plates 204 on the steel arch frame body at both ends along the tunnel wall arch direction are fixedly installed on the tunnel bottom by screws. The present invention can fix the steel arch frame body at both ends along the tunnel wall arch direction on the plane of the tunnel bottom by screws, and the structural design is ingenious.

[0036] See also Figures 1 to 8 The present invention also provides a method for constructing a primary lining of a steel arch frame of a layer-biased tunnel, comprising the above-mentioned primary lining structure of a steel arch frame of a layer-biased tunnel, and the primary lining construction method comprises: Preparation steps: Use a total station or laser scanner to scan the mountain data of the entire tunnel to be excavated to obtain basic information such as the ground elevation and slope of the mountain. Combine drilling exploration methods and geological analysis methods to determine the rock formation information such as the inclination, dip and strike of the tunnel rock mass, determine the bedding state of the tunnel surrounding rock, and perform numerical simulation analysis on the eccentric load of each section of the excavation path. The numerical analysis software can use numerical software such as Phase2, UDEC or FLAC. Through the numerical simulation calculation results, the specific eccentric load size borne by the tunnel during the process of passing through the mountain and the deformation of the tunnel under the initial lining support condition are obtained; Excavation steps: digging tunnels in the mountain; In the excavation step, taking a typical single-track railway tunnel as an example, the excavation height is 10.29m and the width is 8.24m; Testing steps: installing the earth pressure sensor 701 to the spandrel 603, the waist 602 and the foot 601 of the surrounding rock walls on both sides of the tunnel to measure the eccentric load of each supporting section of the tunnel wall in the tunnel; In the detection step, taking the Laoshan Tunnel of the Guangxi section of the Huangtong to Baise-Baise Railway as an example, the measured values ​​of the surrounding rock loads on the arch waist 602 on the left and right sides of the tunnel were measured by the earth pressure sensor 701 to be 575.5 kPa and 210.2 kPa. The surrounding rock loads on the left and right sides are quite different, and the eccentric pressure is significant.

[0037] Steps for selecting the steel arch frame body: according to the range of the eccentric load of each supporting section of the tunnel wall, select I-shaped I-beam as the steel arch frame body, which can withstand a load not less than the smallest eccentric load in each supporting section of the tunnel wall; In the steel arch body selection step, hot-rolled I20b steel (size: 200mm(H)×102mm(b)×9mm(d)×11.4mm(t)) is selected according to the specific size of the bias load in the tunnel in the detection step, and the maximum load-bearing capacity is 390MPa; Construction steps: The eccentric loads received by different supporting sections are divided into two categories. The first category is the larger load received at the arch waist 602, and the second category is the load received at the arch shoulder 603 and the arch foot 601. The first load position and the second load position are respectively allocated a corresponding number of steel units. The steel units are prefabricated outside the tunnel and assembled into a steel arch frame body inside the tunnel. The steel arch frame bodies of each supporting section are fixedly connected by the first connecting unit or the second connecting unit to support the entire tunnel wall along its arch direction.

[0038] See also Figures 1 to 8 In the steel arch frame body selection step, the force load of the single steel arch frame body selected is not less than the minimum bias load in each supporting segment.

[0039] In this embodiment, after the earth pressure sensor 701 measures the bias load of each support section of the tunnel wall in the tunnel, the range of the bias load of each support section of the tunnel wall will be obtained. When selecting the steel arch frame body, it is only necessary to select the steel arch frame body that can withstand a load not less than the minimum bias load in each support section of the tunnel wall, and then distribute the corresponding number of steel arch frame bodies in each support section, so that the bias load in each support section is less than the load that the steel arch frame body can withstand. The present invention can select a suitable steel arch frame body according to the size of the bias load of the support section in the tunnel, so that the steel arch frame body can be reasonably used.

[0040] See also Figures 1 to 8 In the construction steps, when the support section requires multiple steel arch frame bodies to support it, the multiple steel arch frame bodies are arranged in parallel along the axial direction of the tunnel.

[0041] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A primary lining structure of a steel arch frame in a layer-by-layer biased tunnel, characterized in that: The primary lining structure comprises: A plurality of steel arch frame bodies, which divide the tunnel wall into a plurality of support sections along the curvature direction of the tunnel wall, each support section corresponds to at least one steel arch frame body, and the entire tunnel wall is supported along the curvature direction by the steel arch frame bodies in all the support sections; A first connection unit, wherein the first connection unit includes a pad, and when the number of steel arch frame bodies of two adjacent support sections is the same, the steel arch frame bodies are connected by the pad; The second connecting unit includes an expansion component. When the number of steel arch frame bodies in two adjacent supporting sections is different, the steel arch frame bodies in the two adjacent supporting sections are connected by the expansion component. The expansion component is installed at the connection of the steel arch frame bodies with a smaller number in the two adjacent supporting sections to lengthen the length of the connection of the steel arch frame bodies along the axial direction of the tunnel.

2. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 1 is characterized by: The steel arch frame body includes a waist plate, an upper wing plate, a lower wing plate and two end plates, and the waist plate, the upper wing plate and the lower wing plate are all arc-shaped plates; The upper wing plate is fixedly connected to one end of the waist plate close to the tunnel wall, and the lower wing plate is fixedly connected to one end of the waist plate away from the tunnel wall, and the upper wing plate and the lower wing plate are arranged opposite to each other; One end of the waist plate, the upper wing plate and the lower wing plate along the direction of the tunnel wall camber is located in the same plane and the plane is a first plane, and the other end of the waist plate, the upper wing plate and the lower wing plate along the direction of the tunnel wall camber is located in the same plane and the plane is a second plane, one of the end plates is fixed on the first plane, and the other end plate is fixed on the second plane; The end plates of the steel arch frame bodies in two adjacent support sections are fixedly connected via a pad or an expansion component.

3. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 2 is characterized by: The arc length of the upper wing plate is greater than the arc length of the lower wing plate.

4. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 2 is characterized by: The waist plate, the upper wing plate and the lower wing plate are connected to form an I-beam, and the left and right sides of the waist plate are both provided with arc grooves; The expansion assembly includes two mounting members, one of which is mounted on the left end of the leftmost end plate in the support section, and the other is mounted on the right end of the rightmost end plate in the support section; The mounting parts each include a mounting plate, a first extending plate and a second extending plate, wherein the first extending plate and the second extending plate are fixedly connected to the same end surface of the mounting plate, and the first extending plate and the second extending plate are arranged in parallel; The first extended plate is fitted to the end of the end plate away from the waist plate, and the opposite end surfaces of the first extended plates on both sides are kept in contact; The second extending plate extends into the arc-shaped groove, and the second extending plate is attached to the end surface of the end plate away from the first extending plate; In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates of the steel arch frame bodies with fewer numbers in the support section fix the end plates of the steel arch frame bodies with more numbers in the support section.

5. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 4 is characterized by: The primary lining structure further includes a first support rod, one end of which is detachably connected to the waist plate, and the other end of which is detachably connected to the mounting plate; The first support rod is arranged tilted.

6. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 4 is characterized by: The primary lining structure also includes a plurality of second support rods; One end of the second support rod is fixedly connected to the upper wing plate, and the other end of the second support rod is fixedly connected to the lower wing plate.

7. The primary lining structure of a steel arch frame in a layer-by-layer biased tunnel according to claim 1 is characterized by: The steel arch frame bodies at both ends along the tunnel wall arch direction are fixedly connected to the tunnel bottom through end plates.

8. A method for constructing a primary lining of a steel arch frame of a bedding biased tunnel, comprising a primary lining structure of a steel arch frame of a bedding biased tunnel as claimed in any one of claims 1 to 7, characterized in that: The primary lining construction method comprises: Preparation steps: Scan the mountain data of the entire tunnel to be excavated and perform numerical simulation of the eccentric load at various locations along the excavation path; Excavation steps: digging a tunnel in the mountain; Testing steps: measuring the eccentric load of each supporting section of the tunnel wall in the tunnel; Steel arch frame body selection step: according to the range of the bias load of each supporting section of the tunnel wall, a steel arch frame body is selected from steel arch frame bodies that can withstand different loads; Construction steps: Different numbers of steel arch frame bodies are distributed according to the bias loads received by different support sections, and the steel arch frame bodies of each support section are fixedly connected through the first connecting unit or the second connecting unit to support the entire tunnel wall along its arch direction.

9. The method for constructing the primary lining of a steel arch frame in a layer-by-layer biased tunnel according to claim 8, characterized in that: In the steel arch frame body selection step, the force load of the selected single steel arch frame body is not less than the minimum bias load in each supporting section.

10. The method for constructing the primary lining of a steel arch frame in a layer-by-layer biased tunnel according to claim 8, characterized in that: In the construction steps, when the support section requires multiple steel arch frame bodies for support, the multiple steel arch frame bodies are arranged in parallel along the axial direction of the tunnel.

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