A type of initial lining structure and construction method for steel arch frame in parallel-bedding tunnels under eccentric pressure

Abstract

This invention provides a preliminary lining structure and construction method for a steel arch frame in a tunnel with bedding parallel and biased pressure, belonging to the technical field of tunnel preliminary lining. It includes a steel arch frame body, a first connecting unit, and a second connecting unit. Several steel arch frame bodies divide the tunnel wall into several support sections along the camber direction. Based on the different bedding parallel and biased pressure effects within each support section, a corresponding number of steel arch frame bodies are set in each support section. When the number of steel arch frame bodies in two adjacent support sections is the same, the steel arch frame bodies are connected by the first connecting unit. When the number of steel arch frame bodies in two adjacent support sections is different, the steel arch frame bodies are connected by the second connecting unit. This allows for enhanced support of support sections with significant bedding parallel and biased pressure effects by setting multiple steel arch frame bodies.

Description

Technical Field

[0001] This invention belongs to the technical field of tunnel primary lining, and in particular relates to a steel arch primary lining structure and construction method for a layered biased tunnel. Background Technology

[0002] A bedding-parallel biased tunnel refers to a tunnel in which the surrounding strata exhibit both bedding and bias effects. During tunnel construction, these effects cause redistribution and deformation of the strata. Therefore, the initial lining of a bedding-parallel biased tunnel is more complex in terms of the layout and quantity of steel arch structures compared to that of a regular tunnel.

[0003] Chinese invention patent CN111425217A discloses "A reusable prefabricated arch structure and its construction method." This invention comprises at least three steel arch frames connected by reinforcing bars, each frame connected to an arch base. Orifice pipes are arranged at the top of the steel arch frames. When using the arch structure, the orifice pipes are fixed one-to-one within the large pipe shed. The three bottom steel arch frames, through the orifice pipes, provide fixation and support for the large pipe shed. After positioning the prefabricated arch structure, pipe shed construction can proceed quickly. The prefabricated arch structure does not require high foundation bearing capacity. When encountering steep, undulating mountainous terrain or biased tunnel entrances, the prefabricated arch structure provided by this solution allows for "zero" excavation of the side slopes, thus avoiding the safety hazards of excessively high side slopes and inclines at tunnel entrances. It also achieves environmental harmony, embodying the concept of green highways. However, when supporting the bedding-parallel biased tunnel, this invention only uses multiple steel arches connected by steel bars to strengthen the support in all parts of the tunnel. In the bedding-parallel biased tunnel, only the areas with bedding and greater bias effects require two or more steel arches for reinforcement. Therefore, the multiple steel arches in this invention do not play their due supporting role, resulting in a waste of steel arches.

[0004] Therefore, its shortcoming is that, during the construction of tunnels with bedding and biased pressure, this invention cannot only strengthen the support in areas with bedding and biased pressure effects. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a preliminary lining structure and construction method for a steel arch frame in a bedding-parallel biased tunnel, which solves the problem that the prior art cannot strengthen the support only for areas with large bedding-parallel and biased effects.

[0006] To achieve the above and other related objectives, the present invention provides a preliminary lining structure for a bedding-parallel biased tunnel steel arch frame, the preliminary lining structure comprising:

[0007] Several steel arch frame bodies divide the tunnel wall into several support sections along the camber direction of the tunnel wall. Each support section corresponds to at least one steel arch frame body. The entire tunnel wall is supported along its camber direction by the steel arch frame bodies in all support sections.

[0008] The first connecting unit includes a pad. When the number of steel arch frame bodies in two adjacent support sections is the same, the steel arch frame bodies are connected by the pad.

[0009] The second connecting unit includes an extension component. When the number of steel arch frame bodies in two adjacent support sections is different, the steel arch frame bodies in the two adjacent support sections are connected by the extension component. The extension component is installed at the connection point of the steel arch frame bodies with a smaller number in the two adjacent support sections to lengthen the length of the connection point of the steel arch frame bodies along the tunnel axial direction.

[0010] 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, wherein the waist plate, the upper wing plate and the lower wing plate are all arc-shaped plates;

[0011] The upper wing plate is fixed to one end of the waist plate near the tunnel wall, and the lower wing plate is fixed to one end of the waist plate away from the tunnel wall. The upper wing plate and the lower wing plate are arranged opposite to each other.

[0012] The waist plate, upper wing plate and lower wing plate are located at one end along the tunnel wall camber direction and this plane is the first plane. The other ends of the waist plate, upper wing plate and lower wing plate are located at the same plane along the tunnel wall camber direction and this plane is the second plane. One of the end plates is fixed to the first plane and the other end plate is fixed to the second plane.

[0013] The end plates of the steel arch frame bodies in two adjacent support sections are fixedly connected by pads or extension components.

[0014] Alternatively, the arc length of the upper wing plate may be greater than that of the lower wing plate.

[0015] As an optional solution, the waist plate, upper wing plate, and lower wing plate are connected to form an I-beam, and the waist plate has arc-shaped grooves on both the left and right sides.

[0016] The expansion assembly includes two mounting pieces, one of which is installed at the left end of the leftmost end plate within the support section, and the other is installed at the right end of the rightmost end plate within the support section.

[0017] Each mounting component includes a mounting plate, a first protruding plate, and a second protruding plate. The first protruding plate and the second protruding plate are fixed to the same end face of the mounting plate, and the first protruding plate and the second protruding plate are arranged in parallel.

[0018] The first protruding plate is attached to the end of the end plate away from the waist plate, and the opposite end faces of the two first protruding plates remain attached;

[0019] The second protruding plate extends into the arc-shaped groove, and the second protruding plate is attached to the end face of the end plate away from the first protruding plate;

[0020] In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates of the fewer steel arch frame bodies in the support section fix and connect to the end plates of the more numerous steel arch frame bodies in the support section.

[0021] As an optional solution, the initial 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.

[0022] The first support rod is inclined.

[0023] As an optional solution, the primary liner structure also includes several second support rods;

[0024] 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.

[0025] As an optional solution, the steel arch frame bodies at both ends along the tunnel wall camber direction are fixedly connected to the bottom of the tunnel through end plates.

[0026] This invention also provides a method for constructing a preliminary lining of a steel arch frame for a bedding-parallel pressure tunnel, comprising the aforementioned preliminary lining structure of a steel arch frame for a bedding-parallel pressure tunnel, wherein the preliminary lining construction method includes:

[0027] Preparation steps: Scan the mountain data of the entire tunnel to be excavated and perform numerical simulation of the eccentric load at various points along the excavation path;

[0028] Excavation steps: Excavate a tunnel into the mountain;

[0029] Inspection steps: Measure the eccentric load on each support section of the tunnel wall inside the tunnel;

[0030] The steps for selecting the steel arch frame body are as follows: Based on the range of eccentric loads on each support section of the tunnel wall, select a steel arch frame body that can withstand different loads.

[0031] Construction steps: Distribute different numbers of steel arch frame bodies according to the eccentric loads on different support sections, and fix the steel arch frame bodies of each support section together through the first connection unit or the second connection unit to support the entire tunnel wall along its arch direction.

[0032] As an optional solution, in the steel arch frame body selection step, the force load of the selected individual steel arch frame body is not less than the minimum eccentric load among the support sections.

[0033] As an optional solution, in the construction steps, when the support section requires multiple steel arch frame bodies for support, the multiple steel arch frame bodies are arranged side by side along the axial direction of the tunnel.

[0034] As described above, the initial lining structure and construction method of the steel arch frame for tunnels with bedding-parallel eccentric pressure according to the present invention have at least the following beneficial effects:

[0035] 1. The present invention can set different numbers of steel arch frame bodies in each support section according to the different bedding and bias effects of each support section in the tunnel, so as to strengthen the support of the support section with large bedding and bias effects by setting multiple steel arch frame bodies.

[0036] 2. When the number of steel arch frame bodies in two adjacent support sections is not the same, an installation piece is inserted into the left end of the leftmost end plate of the fewer steel arch frame bodies and into the right end of the rightmost end plate. Then, the end plates of the steel arch frame bodies in the two adjacent support sections are fixedly connected by bolts or welding. Attached Figure Description

[0037] Figure 1 The diagram shown is a three-dimensional structural schematic of the present invention.

[0038] Figure 2 The diagram shows a structural schematic of the present invention when the number of steel arch frame bodies in two adjacent support sections is the same.

[0039] Figure 3 The diagram shows a structural schematic of the present invention when the number of steel arch frame bodies in two adjacent support sections is different.

[0040] Figure 4 The diagram shown is an exploded view related to the mounting components of this invention.

[0041] Figure 5 Shown as the present invention Figure 4 A magnified view of point A in the image;

[0042] Figure 6 The diagram shown is a structural schematic related to the arc-shaped groove of the present invention.

[0043] Figure 7 The diagram shows the structural schematics related to the arch shoulder, arch waist, and arch foot of the present invention.

[0044] Figure 8 The diagram shown is a structural schematic of the I-beam dimension markings of this invention.

[0045] In the diagram: 101, pad;

[0046] 201. Waist plate; 202. Upper wing plate; 203. Lower wing plate; 204. End plate;

[0047] 301. Arc-shaped groove; 302. Mounting plate; 303. First protruding plate; 304. Second protruding plate; 305. Insertion slot;

[0048] 401. First support rod;

[0049] 501. Second support rod;

[0050] 601. Arched legs; 602. Arched back; 603. Arched shoulders;

[0051] 701. Earth pressure sensor. Detailed Implementation

[0052] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0053] Please see Figures 1 to 8 It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0054] The following embodiments are for illustrative purposes only. These embodiments can be combined and are not limited to the content shown in any single embodiment below.

[0055] Please see Figure 1 and Figure 2 This invention provides a primary lining structure for a steel arch frame in a bedding-parallel biased tunnel, the primary lining structure comprising:

[0056] Several steel arch frame bodies divide the tunnel wall into several support sections along the camber direction of the tunnel wall. Each support section corresponds to at least one steel arch frame body. The entire tunnel wall is supported along its camber direction by the steel arch frame bodies in all support sections.

[0057] When multiple steel arch frame bodies correspond to a support section, the multiple steel arch frame bodies are arranged side by side along the axial direction of the tunnel.

[0058] The first connecting unit includes a pad 101. When the number of steel arch frame bodies in two adjacent support sections is the same, the steel arch frame bodies are connected by the pad 101.

[0059] The second connecting unit includes an extension component. When the number of steel arch frame bodies in two adjacent support sections is different, the steel arch frame bodies in the two adjacent support sections are connected by the extension component. The extension component is installed at the connection point of the steel arch frame bodies with a smaller number in the two adjacent support sections to lengthen the length of the connection point of the steel arch frame bodies along the tunnel axial direction.

[0060] In this embodiment, when the steel arch frame body supports the tunnel wall, the steel arch frame bodies between adjacent support sections are connected by pads 101 or extension components to support the entire tunnel wall along its arch direction. This invention can set different numbers of steel arch frame bodies according to the different bedding and bias effects of each support section within the tunnel, thereby enabling reinforced support for support sections with significant bedding and bias effects by setting multiple steel arch frame bodies.

[0061] Please see 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. The waist plate 201, the upper wing plate 202 and the lower wing plate 203 are all arc-shaped plates.

[0062] The upper wing plate 202 is fixed to one end of the waist plate 201 near the tunnel wall, and the lower wing plate 203 is fixed 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.

[0063] The waist plate 201, upper wing plate 202 and lower wing plate 203 are located at one end along the tunnel wall camber direction and this plane is the first plane. The other ends of the waist plate 201, upper wing plate 202 and lower wing plate 203 are located at the same plane along the tunnel wall camber direction and this plane is the second plane. One of the end plates 204 is fixed to the first plane and the other end plate 204 is fixed to the second plane.

[0064] The end plates 204 of the steel arch frame bodies in two adjacent support sections are fixedly connected by pads 101 or extension components.

[0065] The method of fixing the end plates 204 that are close to each other on the steel arch frame body is not limited here. It can be fixed by bolts or by welding.

[0066] In this embodiment, when the steel arch frame body supports the tunnel wall, the end plates 204 of the steel arch frame body that are close to each other between adjacent support sections are connected by pads 101 or expansion components to support the entire tunnel wall along its arch direction. This invention cleverly connects the steel arch frame bodies by using the end plates 204 of the steel arch frame body in conjunction with pads 101 or expansion components.

[0067] Please see Figure 2 The arc length of the upper wing plate 202 is greater than the arc length of the lower wing plate 203.

[0068] In this embodiment, when two adjacent steel arch frames installed inside the tunnel are subjected to pressure from the tunnel wall, a portion of the forces acting on the two adjacent end plates 204 interact with each other. The steel arch frame body of this invention has an arc-shaped structure, and through the partial interaction of the forces acting on the two adjacent end plates 204, the radial pressure exerted on the steel arch frame body by the tunnel wall is reduced.

[0069] Please see Figures 3 to 6 The waist plate 201, upper wing plate 202, and lower wing plate 203 are connected to form an I-beam, and the waist plate 201 has arc-shaped grooves 301 on both the left and right sides.

[0070] The expansion assembly includes two mounting pieces, one of which is installed at the left end of the leftmost end plate 204 within the support section, and the other is installed at the right end of the rightmost end plate 204 within the support section.

[0071] Each mounting component includes a mounting plate 302, a first protruding plate 303, and a second protruding plate 304. The first protruding plate 303 and the second protruding plate 304 are fixed to the same end face of the mounting plate 302. The first protruding plate 303 and the second protruding plate 304 are arranged in parallel. The end face of the first protruding plate 303 relative to the second protruding plate 304, the end face of the second protruding end relative to the first protruding plate 303, and the end face of the mounting plate 302 where the first protruding plate 303 and the second protruding plate 304 are fixed are formed with insertion grooves 305.

[0072] The two mounting components are respectively inserted into the fewer end plates 204 in two adjacent support sections through the insertion slots 305. When there is one fewer end plate 204 between two adjacent support sections, the two mounting components are inserted into both sides of the end plate 204 along the tunnel axial direction. When there are two or more fewer end plates 204 between two adjacent support sections, the two mounting components are respectively inserted into the side wall of the outermost end plate 204 along the tunnel axial direction.

[0073] The first protruding plate 303 is attached to the end of the end plate 204 away from the waist plate 201, and the opposite end faces of the two first protruding plates 303 remain attached.

[0074] The second protruding plate 304 extends into the arc-shaped groove 301, and the second protruding plate 304 is attached to the end face of the end plate 204 away from the first protruding plate 303. The end face of the second protruding plate 304 extending into the arc-shaped groove 301 near the waist plate 201 is attached to the waist plate 201. The end face of the second protruding plate 304 extending into the arc-shaped groove 301 near the upper wing plate 202 is attached to the upper wing plate 202. The end face of the second protruding plate 304 extending into the arc-shaped groove 301 near the lower wing plate 203 is attached to the lower wing plate 203.

[0075] In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates 204 of the fewer steel arch frame bodies in the support section are used to fix and connect the end plates 204 of the more numerous steel arch frame bodies in the support section.

[0076] In this embodiment, when the number of steel arch frame bodies in two adjacent support sections is the same, the end plates 204 between the steel arch frame bodies in two adjacent support sections are all attached together by pads 101, and then the steel arch frame bodies in two adjacent support sections are fixedly connected by bolts or welding.

[0077] When the number of steel arch frame bodies in two adjacent support sections is not the same, if there is only one steel arch frame body, an installation component is inserted into both ends of the end plate 204 near the larger number of steel arch frame bodies on the smaller number of steel arch frame bodies. Then, the end plates 204 of the adjacent steel arch frame bodies in these two adjacent support sections are fixedly connected by bolts or welding. If there are multiple steel arch frame bodies, an installation component is inserted into the left end of the left end plate 204 near the larger number of steel arch frame bodies on the smaller number of steel arch frame bodies, and an installation component is inserted into the right end of the right end plate 204 on the right side of the smaller number of steel arch frame bodies. Then, the end plates 204 of the adjacent steel arch frame bodies in these two adjacent support sections are fixedly connected by bolts or welding. This invention, by inserting installation components into the end plates 204 of the smaller number of steel arch frame bodies, allows for the installation of different numbers of steel arch frame bodies for support according to the stress conditions of different support sections within the tunnel.

[0078] Please see Figure 1 , Figure 3 and Figure 4 The initial lining structure also includes a first support rod 401, one end of which is detachably connected to the waist plate 201, and the other end of which is detachably connected to the mounting plate 302.

[0079] The first support rod 401 is inclined.

[0080] In this embodiment, when the number of steel arch frame bodies in two adjacent support sections is not the same, after the mounting component is inserted into the end plate 204 of the steel arch frame body in the support section with fewer supports, one end of the first support rod 401 is fixedly connected to the waist plate 201 with bolts, and the other end of the first support rod 401 is fixedly connected to the mounting plate 302 with bolts, so that the first support rod 401 is inclinedly supported on both sides of the waist plate 201 on the steel arch frame body. This invention strengthens the support of the mounting component inserted into the end plate 204 by having the first support rod 401 inclinedly supported between the waist plate 201 and the mounting component.

[0081] Please see Figure 6 The initial lining structure also includes a plurality of second support rods 501;

[0082] 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.

[0083] In this embodiment, the second support rod 501 is supported between the upper wing plate 202 and the lower wing plate 203. The present invention strengthens the support between the upper wing plate 202 and the lower wing plate 203 by supporting the upper wing plate 202 and the lower wing plate 203 with the second support rod 501.

[0084] Please see Figures 1 to 3 The steel arch frame bodies at both ends along the tunnel wall camber direction are fixedly connected to the bottom of the tunnel through end plates 204.

[0085] In this embodiment, when the steel arch frame bodies at both ends along the tunnel wall camber direction are installed to the tunnel bottom, the end plates 204 on the steel arch frame bodies at both ends along the tunnel wall camber direction are fixed to the tunnel bottom with screws. This invention cleverly uses screws to fix the steel arch frame bodies at both ends along the tunnel wall camber direction onto the plane at the tunnel bottom.

[0086] Please see Figures 1 to 8 The present invention also provides a method for constructing a preliminary lining of a steel arch frame for a bedding-parallel pressure tunnel, comprising the aforementioned preliminary lining structure of a steel arch frame for a bedding-parallel pressure tunnel, wherein the preliminary lining construction method includes:

[0087] Preparation steps: Use a total station or laser scanner to scan the entire mountain body data of the tunnel to be excavated, and obtain basic information such as the ground elevation and slope of the mountain body. Combine drilling exploration methods and geological analysis methods to determine the dip angle, dip direction and strike of the tunnel rock mass and other strata occurrence information, determine the bedding state of the surrounding rock of the tunnel, and conduct numerical simulation analysis on the bias load of each section of the excavation path. Numerical analysis software such as Phase2, UDEC or FLAC can be used. Through numerical simulation calculation results, the specific bias load magnitude of the tunnel during the tunnel crossing the mountain and the deformation of the tunnel under the initial lining support condition can be obtained.

[0088] Excavation steps: Excavate a tunnel into the mountain;

[0089] In the excavation process, taking a typical single-track railway tunnel as an example, the excavation height is 10.29m and the width is 8.24m;

[0090] Testing steps: Install the earth pressure sensor 701 at the arch shoulder 603, arch waist 602, and arch foot 601 on both sides of the tunnel surrounding rock to measure the eccentric load of each support section of the tunnel wall inside the tunnel.

[0091] In the testing process, taking the Laoshan Tunnel on the Guangxi section of the Huangtong-Baise Railway as an example, the measured values ​​of the surrounding rock loads on the left and right sides of the tunnel arch waist 602 by the earth pressure sensor 701 were 575.5 kPa and 210.2 kPa, respectively. The difference in the surrounding rock loads on the left and right sides was significant, and the bias pressure was obvious.

[0092] Steps for selecting the steel arch frame body: Based on the range of eccentric loads of each support section of the tunnel wall, select I-beams as the steel arch frame body, which can withstand loads not less than the smallest eccentric load among the support sections of the tunnel wall.

[0093] In the steel arch frame selection step, hot-rolled I20b steel (dimensions of 200mm(H)×102mm(b)×9mm(d)×11.4mm(t)) is selected based on the specific magnitude of the eccentric load in the tunnel during the testing step. The maximum load it can withstand is 390MPa.

[0094] Construction steps: The eccentric loads on different support sections are divided into two categories. The first category is the larger load at the arch waist 602, and the second category is the load at the arch shoulder 603 and arch foot 601. The first and second load locations are assigned corresponding numbers of steel units. The steel units are prefabricated outside the tunnel and assembled inside the tunnel to form the steel arch frame body. The steel arch frame bodies of each support section are fixedly connected through the first or second connecting unit to support the entire tunnel wall along its arch direction.

[0095] Please see Figures 1 to 8In the steel arch frame body selection step, the force load of the selected individual steel arch frame body is not less than the minimum eccentric load in each support section.

[0096] In this embodiment, after the earth pressure sensor 701 measures the eccentric load of each support section of the tunnel wall, the range of the eccentric load for each support section is obtained. When selecting the steel arch frame body, it is only necessary to select the one whose load-bearing capacity is not less than the smallest eccentric load among the support sections of the tunnel wall, and then allocate the corresponding number of steel arch frame bodies to each support section, so that the eccentric load in each support section is less than the load-bearing capacity of the steel arch frame body. This invention can select a suitable steel arch frame body according to the magnitude of the eccentric load of the support section in the tunnel, so that the steel arch frame body can be used reasonably.

[0097] Please see Figures 1 to 8 In the construction steps, when the support section requires multiple steel arch frame bodies for support, the multiple steel arch frame bodies are arranged side by side along the axial direction of the tunnel.

[0098] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can 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 those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for constructing the initial lining of a steel arch frame in a bedding-parallel biased tunnel, characterized in that, The initial lining construction method includes an initial lining structure, which includes: Several steel arch frame bodies divide the tunnel wall into several support sections along the camber direction of the tunnel wall. Each support section corresponds to at least one steel arch frame body. The entire tunnel wall is supported along its camber direction by the steel arch frame bodies in all support sections. The first connecting unit includes a pad. When the number of steel arch frame bodies in two adjacent support sections is the same, the steel arch frame bodies are connected by the pad. The second connecting unit includes an extension component. When the number of steel arch frame bodies in two adjacent support sections is different, the steel arch frame bodies in the two adjacent support sections are connected by the extension component. The extension component is installed at the connection of the fewer steel arch frame bodies in the two adjacent support sections to lengthen the length of the connection of the steel arch frame bodies along the tunnel axial direction. The steel arch frame body includes a waist plate, an upper wing plate, a lower wing plate, and two end plates. The waist plate, upper wing plate, and lower wing plate are all arc-shaped plates. The upper wing plate is fixed to one end of the waist plate near the tunnel wall, and the lower wing plate is fixed to one end of the waist plate away from the tunnel wall. The upper wing plate and the lower wing plate are arranged opposite to each other. The waist plate, upper wing plate and lower wing plate are located at one end along the tunnel wall camber direction and this plane is the first plane. The other ends of the waist plate, upper wing plate and lower wing plate are located at the same plane along the tunnel wall camber direction and this plane is the second plane. One of the end plates is fixed to the first plane and the other end plate is fixed to the second plane. The end plates of the steel arch frame bodies in two adjacent support sections are fixedly connected by pads or extension components; The waist plate, upper wing plate, and lower wing plate are connected to form an I-beam, and the waist plate has arc-shaped grooves on both the left and right sides. The expansion assembly includes two mounting pieces, one of which is installed at the left end of the leftmost end plate within the support section, and the other is installed at the right end of the rightmost end plate within the support section. Each mounting component includes a mounting plate, a first protruding plate, and a second protruding plate. The first protruding plate and the second protruding plate are fixed to the same end face of the mounting plate, and the first protruding plate and the second protruding plate are arranged in parallel. The first protruding plate is attached to the end of the end plate away from the waist plate, and the opposite end faces of the two first protruding plates remain attached; The second protruding plate extends into the arc-shaped groove, and the second protruding plate is attached to the end face of the end plate away from the first protruding plate; In two adjacent support sections with different numbers of steel arch frame bodies, the mounting parts inserted into the end plates of the fewer steel arch frame bodies in the support section fix and connect to the end plates of the more numerous steel arch frame bodies in the support section. The initial lining construction method includes: Preparation steps: Scan the mountain data of the entire tunnel to be excavated and perform numerical simulation of the eccentric load at various points along the excavation path; Excavation steps: Excavate a tunnel into the mountain; Inspection steps: Measure the eccentric load on each support section of the tunnel wall inside the tunnel; The steps for selecting the steel arch frame body are as follows: Based on the range of eccentric loads on each support section of the tunnel wall, select a steel arch frame body that can withstand different loads. Construction steps: Distribute different numbers of steel arch frame bodies according to the eccentric loads on different support sections, and fix the steel arch frame bodies of each support section together through the first connection unit or the second connection unit to support the entire tunnel wall along its arch direction.

2. The method for constructing the initial lining of a steel arch frame in a layer-by-layer biased tunnel according to claim 1, characterized in that: The arc length of the upper wing is greater than that of the lower wing.

3. The method for constructing the initial lining of a steel arch frame in a bedding-parallel pressure tunnel according to claim 1, characterized in that: The primary lining structure also 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 inclined.

4. The method for constructing the initial lining of a steel arch frame in a tunnel with in-situ biased pressure according to claim 1, characterized in that: The primary lining structure also includes several 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.

5. The method for constructing the initial lining of a steel arch frame in a tunnel with in-situ biased pressure according to claim 1, characterized in that: The steel arch frame bodies at both ends along the tunnel wall camber direction are fixedly connected to the bottom of the tunnel through end plates.

6. The method for constructing the initial lining of a steel arch frame in a bedding-parallel pressure tunnel according to claim 1, characterized in that: In the steel arch frame body selection step, the force load of the selected individual steel arch frame body is not less than the minimum eccentric load among the support sections.

7. The method for constructing the initial lining of a steel arch frame in a bedding-parallel pressure tunnel according to claim 1, characterized in that: In the construction process, when the support section requires multiple steel arch frame bodies for support, the multiple steel arch frame bodies are arranged side by side along the axial direction of the tunnel.

Images