Double-hole single-track tunnel supporting structure with clear distance of 0.2 m-2m and construction method of double-hole single-track tunnel supporting structure

Abstract

The invention relates to the technical field of tunnel construction, in particular to a double-hole single-track tunnel supporting structure with the clear distance being 0.2-2 m and a construction method of the double-hole single-track tunnel supporting structure. According to the double-hole single-track tunnel supporting structure, the first concrete member is used for filling and reinforcing the middle rock pillar of the tunnel section with the clear distance larger than 0.2 m and smaller than or equal to 2 m, the second concrete member is used for filling and reinforcing the middle rock pillar of the tunnel section with the clear distance equal to 0.2 m, the reinforcing effect of the middle rock pillar is guaranteed, and therefore collapse of the middle rock pillar is avoided; the first concrete member and the second concrete member have high anti-disturbance capacity, construction disturbance on the middle clamping rock pillar can be avoided, collapse of the double-hole single-track tunnel is avoided, construction safety is guaranteed, and therefore the whole process of construction of the double-hole single-track tunnel is accelerated. The construction method comprises the following steps: firstly, carrying out special-shaped section excavation on a preceding hole and a middle clamping rock pillar range together, backfilling concrete in the middle clamping rock pillar range and finishing the support of a preceding hole main hole, and connecting a subsequent hole with a subsequent hole steel frame reserved by the preceding hole after excavation and finishing the support.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to a double-hole single-line tunnel support structure with a net distance of 0.2m-2m and a construction method thereof. Background Art

[0002] The parallel twin-hole ultra-small clearance single-track tunnel is a special tunnel structure between ordinary separated tunnels and multi-arch tunnels, with a clearance of 0.2m to 20m. The current construction method for small clearance tunnels is generally to first reinforce the middle rock pillars with tension anchors, glass fiber anchors, advanced anchor pipe grouting and other construction methods, and then use the three-bench seven-step method, CD method and small pilot tunnel method for excavation.

[0003] Therefore, the current construction method for double-hole single-track tunnels with a clear spacing of 0.2m-2m is relatively cumbersome and complicated, which will increase the construction period; when encountering relatively fragmented rock masses, the reinforcement effect of the middle rock pillars is poor, posing a greater safety risk; in the actual construction process, tunnel over-excavation will further weaken the thickness and strength of the middle rock pillars. In the case of a clear spacing of 0.2m, the middle rock pillars may even no longer exist during tunnel over-excavation. Objective construction disturbances can easily cause deformation of the tunnel support structure. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art in that the construction process of a double-hole single-track tunnel with a net spacing of 0.2m-2m is complicated, the reinforcement effect of the rock pillars in the middle is poor, and the rock pillars in the middle are easily over-excavated and easily disturbed by construction, and to provide a double-hole single-track tunnel support structure with a net spacing of 0.2m-2m and a construction method thereof.

[0005] In a first aspect, the present invention provides a double-hole single-line tunnel support structure with a clearance of 0.2m-2m, comprising: Several first tunnel support structures and several second tunnel support structures are arranged along the direction of the double-hole single-track tunnel, with the clear distance of the double-hole single-track tunnel being greater than 0.2m and less than or equal to 2m, and several second tunnel support structures are arranged at intervals of 0.2m in the double-hole single-track tunnel; The first tunnel support structure includes a leading tunnel steel frame, a leading tunnel main tunnel support, a leading tunnel upper step special-shaped steel frame, a first rear tunnel lower step reserved steel frame, a first rear tunnel upper step main tunnel steel frame and a first rear tunnel lower step main tunnel steel frame; the first leading tunnel tunnel steel frame is connected to the leading tunnel main tunnel support to form a first leading tunnel support structure, one end of the leading tunnel upper step special-shaped steel frame is connected to the leading tunnel steel frame, and the other end is connected to the first rear tunnel lower step reserved steel frame; the leading tunnel upper step special-shaped steel frame is connected to the end of the first rear tunnel upper step main tunnel steel frame; one end of the first rear tunnel upper step main tunnel steel frame is connected to the first rear tunnel lower step reserved steel frame, and the other end is connected to the first rear tunnel lower step main tunnel steel frame to form a first rear tunnel support structure, and a first concrete member is provided between the leading tunnel main tunnel support and the first rear tunnel lower step reserved steel frame; The second tunnel support structure includes a leading tunnel upper step main tunnel steel frame, a leading tunnel lower step main tunnel steel frame, a second rear tunnel lower step reserved steel frame, a second rear tunnel upper step main tunnel steel frame and a second rear tunnel lower step main tunnel steel frame; both ends of the leading tunnel upper step main tunnel steel frame are respectively connected to the leading tunnel lower step main tunnel steel frame to form a second leading tunnel support structure; one end of the second rear tunnel upper step main tunnel steel frame is connected to the second rear tunnel lower step reserved steel frame, and the other end is connected to the second rear tunnel lower step main tunnel steel frame to form a second rear tunnel support structure; the leading tunnel lower step main tunnel steel frame is connected to the second rear tunnel upper step main tunnel steel frame, and the second rear tunnel lower step reserved steel frame is connected to the leading tunnel upper step main tunnel steel frame; a second concrete member is provided between the second rear tunnel lower step reserved steel frame and the leading tunnel lower step main tunnel steel frame.

[0006] The present invention provides a double-hole single-track tunnel support structure with a net spacing of 0.2m-2m. The double-hole single-track tunnel is supported in sections, so that the tunnel section with a net spacing greater than 0.2m and less than or equal to 2m is supported by the first tunnel support structure, and the tunnel section with a net spacing of 0.2m is supported by the second tunnel support structure. Different support schemes are used to support the double-hole single-track tunnel with different net spacings, thereby ensuring the support strength of the tunnel and avoiding tunnel collapse; the first concrete component is used to fill and reinforce the middle rock pillars in the tunnel section with a net spacing greater than 0.2m and less than or equal to 2m, and the second concrete component is used to fill and reinforce the middle rock pillars in the tunnel section with a net spacing equal to 0.2m, so that the reinforcement effect of the middle rock pillars is guaranteed, thereby avoiding collapse of the middle rock pillars; the first concrete component and the second concrete component have strong anti-disturbance ability, can prevent the middle rock pillars from being disturbed by construction, avoid collapse of the double-hole single-track tunnel, ensure construction safety, and thus accelerate the overall process of double-hole single-track tunnel construction.

[0007] Preferably, the leading tunnel steel frame is further provided with a first leading tunnel inverted arch steel frame, one end of the first leading tunnel inverted arch steel frame is connected to the leading tunnel steel frame, and the other end is connected to the leading tunnel main tunnel support; the first rear tunnel lower step reserved steel frame is provided with a first rear tunnel inverted arch steel frame, one end of the first rear tunnel inverted arch steel frame is connected to the first rear tunnel lower step reserved steel frame, and the other end is connected to the first rear tunnel lower step main tunnel steel frame.

[0008] The first leading tunnel support structure and the first rear tunnel support structure are reinforced respectively by the first leading tunnel inverted arch steel frame and the first rear tunnel inverted arch steel frame; the first leading tunnel inverted arch steel frame is located at the bottom of the leading tunnel, and the first rear tunnel inverted arch steel frame is located at the bottom of the rear tunnel.

[0009] Preferably, the main tunnel steel frame of the lower step of the leading tunnel is provided with a second leading tunnel inverted arch steel frame, and both ends of the second leading tunnel inverted arch steel frame are respectively connected to the main tunnel steel frame of the lower step of the leading tunnel; the reserved steel frame of the lower step of the second rear tunnel is provided with a second rear tunnel inverted arch steel frame, and one end of the second rear tunnel inverted arch steel frame is connected to the reserved steel frame of the lower step of the second rear tunnel, and the other end is connected to the main tunnel steel frame of the lower step of the second rear tunnel.

[0010] The second leading tunnel support structure and the second rear tunnel support structure are reinforced respectively by the second leading tunnel inverted arch steel frame and the second rear tunnel inverted arch steel frame; the second leading tunnel inverted arch steel frame is located at the bottom of the leading tunnel, and the second rear tunnel inverted arch steel frame is located at the bottom of the rear tunnel.

[0011] In a second aspect, the present invention provides a construction method for a double-hole single-track tunnel support structure with a clearance of 0.2m-2m, which is used to form the above-mentioned double-hole single-track tunnel support structure with a clearance of 0.2m-2m, comprising: S1: Implement the construction steps of the first tunnel support structure; S2: Implement the construction steps of the second tunnel support structure; The construction steps of implementing the first tunnel support structure include: A1: Excavation of the first pilot tunnel upper bench: Excavate the pilot tunnel upper bench section of the double-hole single-track tunnel section with a net distance greater than 0.2m and less than or equal to 2m. Expand the rock pillar area between the double-hole single-track tunnels and install the pilot tunnel steel frame and the pilot tunnel upper bench special-shaped steel frame; A2: Excavation of the first pilot tunnel step: Excavate the pilot tunnel step section of the double-tunnel single-track tunnel section with a net distance greater than 0.2m and less than or equal to 2m, and install the pilot tunnel step special-shaped steel frame, the pilot tunnel support, and the reserved steel frame for the first back tunnel step; A3: Excavation of the upper step of the first rear tunnel: Excavate the upper step section of the rear tunnel of a double-hole single-track tunnel with a net distance greater than 0.2m and less than or equal to 2m. When excavating to the special-shaped steel frame of the upper step of the leading tunnel, install the main tunnel steel frame of the upper step of the first rear tunnel, so that the main tunnel steel frame of the upper step of the first rear tunnel is connected to the reserved steel frame of the lower step of the first rear tunnel; A4: Casting of the first concrete component: Cast the first concrete component between the main tunnel support of the leading tunnel and the reserved steel frame at the lower step of the first rear tunnel; A5: Excavation of the first back-end tunnel step: After the excavation of the back-end tunnel step in the double-hole single-track tunnel section with a net distance greater than 0.2m and less than or equal to 2m is completed, the main tunnel steel frame of the first back-end tunnel step is installed on the side of the back-end tunnel away from the middle rock pillar; A6: Complete the installation of the first tunnel support structure: remove the special-shaped steel frame under the steps of the pilot tunnel; The construction steps of implementing the second tunnel support structure include: B1: Excavation of the upper step of the second pilot tunnel: Excavate the upper step section of the pilot tunnel of the double-hole single-track tunnel section with a net distance of 0.2m, and install the main tunnel steel frame of the upper step of the pilot tunnel; B2: Excavation of the lower step of the second pilot tunnel: Excavate the upper step section of the pilot tunnel in the double-hole single-track tunnel section with a net distance of 0.2m. Expand the rock pillar area between the double-hole single-track tunnels. Install the main tunnel steel frame of the lower step of the pilot tunnel and the reserved steel frame of the lower step of the second rear tunnel. Connect the reserved steel frame of the lower step of the second rear tunnel to the main tunnel steel frame of the lower step of the pilot tunnel. B3: Excavation of the upper step of the second rear tunnel: Excavate the upper step section of the rear tunnel of the double-hole single-track tunnel with a net distance of 0.2m. When excavating to the reserved steel frame of the lower step of the second rear tunnel, install the main tunnel steel frame of the upper step of the second rear tunnel and connect it with the reserved steel frame of the lower step of the second rear tunnel; B4: Casting the second concrete component: Cast the second concrete component between the reserved steel frame of the lower step of the second rear tunnel and the main tunnel steel frame of the lower step of the leading tunnel; B5: Excavation of the lower step of the second back tunnel: After the lower step of the back tunnel of the double-hole single-track tunnel section with a net distance of 0.2m is excavated, the main tunnel steel frame of the lower step of the second back tunnel is installed on the side of the back tunnel away from the middle rock pillar.

[0012] The present invention provides a construction method for a double-hole single-track tunnel support structure with a net spacing of 0.2m-2m. First, the leading hole and the middle rock column range are excavated with a special section, the middle rock column range is backfilled with concrete and the leading hole support is completed, and after the rear hole is excavated, it is connected with the rear hole steel frame reserved for the leading hole and the support is completed; thereby avoiding the problems of tunnel over-excavation and weak reinforcement and protection of the middle rock column; the method has strong on-site operability and high construction safety factor; the strength of the middle rock column range is improved, and good radial constraint is provided for the support structure, thereby improving the stability of the middle rock column; the micro-step method is used to construct the first tunnel support structure and the second tunnel support structure, so that the construction safety risk is effectively controlled, the construction process of the double-hole single-track tunnel with a net spacing of 0.2m-2m is simplified, the construction efficiency is improved, the construction period is shortened, and the risk construction time is reduced; by expanding the middle rock column and replacing the middle rock column with concrete, the excavation volume is reduced, the excavation cost is reduced, the construction period is shortened, and the construction time cost is reduced.

[0013] Preferably, in A4, the first concrete component fills the gap between the main tunnel support of the leading tunnel and the reserved steel frame of the lower step of the first rear tunnel, and the top of the first concrete component is connected to the special-shaped steel frame of the upper step of the leading tunnel.

[0014] The first concrete component supports the special-shaped steel frame on the upper step of the pilot tunnel. Through concrete replacement, the first concrete component is used as a middle rock column to ensure the supporting strength of the tunnel section with a net distance greater than 0.2m and less than or equal to 2m.

[0015] Preferably, in B4, the first concrete component fills the gap between the reserved steel frame of the lower step of the second rear tunnel and the main tunnel steel frame of the lower step of the advance tunnel.

[0016] The second concrete component supports the reserved steel frame of the second rear tunnel step and the main tunnel steel frame of the first tunnel step. Through concrete replacement, the second concrete component is used as a middle rock column to ensure the support strength of the tunnel section with a net distance equal to 0.2m.

[0017] Preferably, in A2, the special-shaped steel frame of the step under the leading tunnel is installed close to the reserved steel frame of the step under the first rear tunnel, and the reserved steel frame of the step under the first rear tunnel is located on the side close to the middle rock column.

[0018] The installation positions of the special-shaped steel frame of the lower step of the leading tunnel and the reserved steel frame of the lower step of the first rear tunnel are made close. After the special-shaped steel frame of the lower step of the leading tunnel is removed, the reserved steel frame of the lower step of the first rear tunnel supports the main tunnel steel frame of the upper step of the second rear tunnel, so as to avoid a large change in the force of the supporting structure of the first rear tunnel after the special-shaped steel frame of the lower step of the leading tunnel is removed, thereby ensuring the support stability of the double-hole single-track tunnel.

[0019] Preferably, in A2, before installing the special-shaped steel frame of the lower step of the pilot tunnel, the main tunnel support of the pilot tunnel and the reserved steel frame of the lower step of the first rear tunnel, sprayed concrete is used to fill the expanded middle rock column range densely.

[0020] Use concrete to reinforce the middle rock column area to reduce the risk of collapse within the middle rock column area.

[0021] Preferably, in A2, the special-shaped steel frame of the lower step of the pilot tunnel is connected to the special-shaped steel frame of the upper step of the pilot tunnel by bolts.

[0022] The use of bolt connection makes it easier to install and dismantle the special-shaped steel frame of the steps under the tunnel, which can speed up the construction process and reduce disturbance.

[0023] Preferably, in A6, before removing the special-shaped steel frame of the step below the leading tunnel, the step section below the first trailing tunnel is excavated until the special-shaped steel frame of the step below the leading tunnel is completely exposed in the trailing tunnel.

[0024] It is convenient to dismantle the special-shaped steel frame of the steps under the pilot tunnel, reduce disturbance, and ensure the support stability of the double-hole single-line tunnel.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a support structure for a double-hole single-track tunnel with a clearance of 0.2m-2m. The double-hole single-track tunnel is supported in sections, so that the tunnel section with a clearance of greater than 0.2m and less than or equal to 2m is supported by a first tunnel support structure, and the tunnel section with a clearance of 0.2m is supported by a second tunnel support structure. Different support schemes are used to support the double-hole single-track tunnel with different clearances, thereby ensuring the support strength of the tunnel and preventing tunnel collapse. The first concrete component is used to fill and reinforce the middle rock pillars in the tunnel section with a clearance of greater than 0.2m and less than or equal to 2m, and the second concrete component is used to fill and reinforce the middle rock pillars in the tunnel section with a clearance of 0.2m, so that the reinforcement effect of the middle rock pillars is ensured, thereby preventing the collapse of the middle rock pillars. The first concrete component and the second concrete component have strong anti-disturbance capabilities, which can prevent the middle rock pillars from being disturbed during construction, prevent the collapse of the double-hole single-track tunnel, ensure construction safety, and thus accelerate the overall progress of the double-hole single-track tunnel construction. 2. The present invention provides a construction method for a double-hole single-track tunnel support structure with a net spacing of 0.2m-2m. First, the leading hole and the middle rock column range are excavated with a special section, the middle rock column range is backfilled with concrete and the leading hole support is completed, and after the rear hole is excavated, it is connected with the rear hole steel frame reserved for the leading hole and the support is completed; thereby avoiding the problems of tunnel over-excavation and weak reinforcement and protection of the middle rock column; the method has strong on-site operability and high construction safety factor; the strength of the middle rock column range is improved, and good radial constraint is provided for the support structure, thereby improving the stability of the middle rock column; the micro-step method is used to construct the first tunnel support structure and the second tunnel support structure, so that the construction safety risk is effectively controlled, simplifying the construction process of the double-hole single-track tunnel with a net spacing of 0.2m-2m, improving construction efficiency, shortening construction period, and reducing risk construction time; by expanding the middle rock column and replacing the middle rock column with concrete, the excavation volume is reduced, the excavation cost is reduced, the construction period is shortened, and the construction time cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a double-hole single-track tunnel with a clearance of 0.2m-2m according to Example 1 of the present invention; Figure 2 This is a schematic structural diagram of a first tunnel support structure of a double-hole single-track tunnel with a clearance of 0.2m-2m according to Example 1 of the present invention; Figure 3 This is a schematic structural diagram of a second tunnel support structure of a double-hole single-track tunnel with a clearance of 0.2m-2m according to Example 1 of the present invention; Figure 4 Schematic diagram of the upper step excavation of the first pilot hole of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 5 Schematic diagram of the excavation of the lower step of the first pilot hole of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 6 This is a schematic diagram of the installation of a reserved steel frame for the lower step of the first rear tunnel in a construction method of a double-tunnel single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 7 Schematic diagram of the upper step excavation of the first rear tunnel of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 8 Schematic diagram of the excavation of the lower step of the first rear tunnel of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 9This is a schematic diagram of dismantling the special-shaped steel frame under the step of the pilot tunnel in a construction method of a support structure for a double-tunnel single-track tunnel with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 10 Schematic diagram of upper step excavation of the second pilot hole of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 11 Schematic diagram of the excavation of the lower step of the second pilot hole of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 12 Schematic diagram of the upper step excavation of the second rear tunnel of a construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to Example 2 of the present invention; Figure 13 This is a schematic diagram of the excavation of the lower step of the second rear tunnel of a construction method of a double-hole single-track tunnel support structure with a net distance of 0.2m-2m in Example 2 of the present invention.

[0027] Markings in the figure: 1- first hole, 2- second hole, 11-Special-shaped steel frame for the upper step of the pilot tunnel, 12-Special-shaped steel frame for the lower step of the pilot tunnel, 13-Support for the main tunnel of the pilot tunnel, 14-Support steel frame for the upper step of the pilot tunnel, 15-Support steel frame for the lower step of the pilot tunnel, 16-Support steel frame for the tunnel of the pilot tunnel, 161-Arched steel frame, 162-Side support steel frame for the lower step of the pilot tunnel, 21-Reserved steel frame for the lower steps of the first back tunnel, 22-Steel frame for the main hole of the upper steps of the first back tunnel, 23-Steel frame for the main hole of the lower steps of the first back tunnel, 24-Reserved steel frame for the lower steps of the second back tunnel, 25-Steel frame for the main hole of the upper steps of the second back tunnel, 26-Steel frame for the main hole of the lower steps of the second back tunnel, 3- First leading tunnel inverted arch steel frame, 4- First rear tunnel inverted arch steel frame, 5- Second leading tunnel inverted arch steel frame, 6- Second rear tunnel inverted arch steel frame, 7- First concrete component, 8- Second concrete component, 100-Tunnel section with a clear distance of 0.2m for a double-hole single-track tunnel; 101-Tunnel section with a clear distance of greater than 0.2m and less than or equal to 2m for a double-hole single-track tunnel. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0029] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or positional relationship, such as "upper", "lower", "left", "right", "center", "inside", and "outside", are based on the expressions of the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationship are merely for the purpose of facilitating the description of the scheme of the present invention or simplifying the description of the specific embodiments to facilitate the rapid understanding of the scheme by technicians, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship, and therefore should not be understood as limiting the present invention.

[0030] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simply understood that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", and "parallel", and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0031] In addition, the expressions “first”, “second”, “third”, etc. in the terms are merely used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0032] In addition, in the description of the embodiments of the present invention, "several," "plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0033] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0034] Example 1 like Figure 1-Figure 3 As shown, a double-hole single-track tunnel support structure with a clearance of 0.2m-2m is specifically composed of a plurality of first tunnel support structures and a plurality of second tunnel support structures. Along the direction of the double-hole single-track tunnel, a plurality of first tunnel support structures are arranged at intervals in a tunnel section 101 with a clearance of greater than 0.2m and less than or equal to 2m, and a plurality of second tunnel support structures are arranged at intervals in a tunnel section 100 with a clearance of 0.2m in the double-hole single-track tunnel. The first tunnel support structure is composed of a leading tunnel steel frame 16, a leading tunnel main tunnel support 13, a leading tunnel upper step special-shaped steel frame 11, a first rear tunnel lower step reserved steel frame 21, a first rear tunnel upper step main tunnel steel frame 22 and a first rear tunnel lower step main tunnel steel frame 23; the first leading tunnel steel frame 16 is connected to the leading tunnel main tunnel support 13 to form the first leading tunnel support structure, one end of the leading tunnel upper step special-shaped steel frame 11 is connected to the leading tunnel steel frame 16, and the other end is connected to the leading tunnel steel frame 16. The first rear tunnel support structure is connected to the reserved steel frame 21 of the lower step of the first rear tunnel; the special-shaped steel frame 11 of the upper step of the leading tunnel is connected to the end of the main tunnel steel frame 22 of the upper step of the first rear tunnel; one end of the main tunnel steel frame 22 of the upper step of the first rear tunnel is connected to the reserved steel frame 21 of the lower step of the first rear tunnel, and the other end is connected to the main tunnel steel frame 23 of the lower step of the first rear tunnel, forming a first rear tunnel support structure. A first concrete member 7 is provided between the main tunnel support 13 of the leading tunnel and the reserved steel frame 21 of the lower step of the first rear tunnel; The second tunnel supporting structure includes a leading tunnel upper step main tunnel steel frame 14, a leading tunnel lower step main tunnel steel frame 15, a second rear tunnel lower step reserved steel frame 24, a second rear tunnel upper step main tunnel steel frame 25 and a second rear tunnel lower step main tunnel steel frame 26; both ends of the leading tunnel upper step main tunnel steel frame 14 are respectively connected to the leading tunnel lower step main tunnel steel frame 15 to form a second leading tunnel support structure; one end of the second rear tunnel upper step main tunnel steel frame 25 is connected to the second rear tunnel lower step reserved steel frame 24, and the other end is connected to the second rear tunnel lower step main tunnel steel frame 26 to form a second rear tunnel support structure; the leading tunnel lower step main tunnel steel frame 15 is connected to the second rear tunnel upper step main tunnel steel frame 25, and the second rear tunnel lower step reserved steel frame 24 is connected to the leading tunnel upper step main tunnel steel frame 14; a second concrete component 8 is provided between the second rear tunnel lower step reserved steel frame 24 and the leading tunnel lower step main tunnel steel frame 15.

[0035] By supporting the double-hole single-track tunnel in sections, the tunnel section 101 with a net distance greater than 0.2m and less than or equal to 2m is supported by the first tunnel support structure, and the tunnel section 100 with a net distance of 0.2m is supported by the second tunnel support structure. Different support schemes are used to support the double-hole single-track tunnels with different net distances, thereby ensuring the support strength of the tunnel and avoiding tunnel collapse; the first concrete component 7 is used to fill and reinforce the middle rock pillars in the tunnel section with a net distance greater than 0.2m and less than or equal to 2m, and the second concrete component 8 is used to fill and reinforce the middle rock pillars in the tunnel section with a net distance equal to 0.2m, so that the reinforcement effect of the middle rock pillars is guaranteed, thereby avoiding the collapse of the middle rock pillars; the first concrete component 7 and the second concrete component 8 have strong anti-disturbance ability, which can prevent the middle rock pillars from being disturbed by construction, avoid the collapse of the double-hole single-track tunnel, ensure construction safety, and thus accelerate the overall progress of the double-hole single-track tunnel construction.

[0036] Specifically, the special-shaped steel frame 11 of the upper step of the leading tunnel, the special-shaped steel frame 12 of the lower step of the leading tunnel, the main tunnel support 13 of the leading tunnel, the main tunnel steel frame 14 of the upper step of the leading tunnel, the main tunnel steel frame 15 of the lower step of the leading tunnel, the tunnel steel frame 16 of the leading tunnel, the arch steel frame 161, the side support steel frame 162 of the lower step of the leading tunnel, the reserved steel frame 21 of the lower step of the first rear tunnel, the main tunnel steel frame 22 of the upper step of the first rear tunnel, the main tunnel steel frame 23 of the lower step of the first rear tunnel, the reserved steel frame 24 of the lower step of the second rear tunnel, the main tunnel steel frame 25 of the upper step of the second rear tunnel, the main tunnel steel frame 26 of the lower step of the second rear tunnel, the first leading tunnel inverted arch steel frame 3, the first rear tunnel inverted arch steel frame 4, the second leading tunnel inverted arch steel frame 5, and the second rear tunnel inverted arch steel frame 6 are steel beams with different curvatures. Specifically, as Figure 1 As shown, the double-hole single-track tunnel has a leading tunnel 1 and a trailing tunnel 2. Along the direction of the double-hole single-track tunnel, the clear distance of the tunnel section with a clear distance of 0.2m and less than or equal to 2m gradually changes from 2m to 0.2m, and the clear distance of the tunnel section with a clear distance of 0.2m is constant at 0.2m.

[0037] In one or several embodiments, the leading tunnel steel frame 16 is also provided with a first leading tunnel inverted arch steel frame 3, one end of the first leading tunnel inverted arch steel frame 3 is connected to the leading tunnel steel frame 16, and the other end is connected to the leading tunnel main tunnel support 13; the first rear tunnel lower step reserved steel frame 21 is provided with a first rear tunnel inverted arch steel frame 4, one end of the first rear tunnel inverted arch steel frame 4 is connected to the first rear tunnel lower step reserved steel frame 21, and the other end is connected to the first rear tunnel lower step main tunnel steel frame 23; the leading tunnel lower step main tunnel steel frame 15 is provided with a second leading tunnel inverted arch steel frame 5, and the two ends of the second leading tunnel inverted arch steel frame 5 are respectively connected to the leading tunnel lower step main tunnel steel frame 15; the second rear tunnel lower step reserved steel frame 24 is provided with a second rear tunnel inverted arch steel frame 6, one end of the second rear tunnel inverted arch steel frame 6 is connected to the second rear tunnel lower step reserved steel frame 24, and the other end is connected to the second rear tunnel lower step main tunnel steel frame 26.

[0038] Specifically, the pilot tunnel steel frame 16 is composed of an arched steel frame 161 at the top of the pilot tunnel and a pilot tunnel lower step side support steel frame 162 arranged on the side of the pilot tunnel away from the middle rock pillar. The end of the arched steel frame 161 is connected to the pilot tunnel lower step side support steel frame 162; one end of the first pilot tunnel inverted arch steel frame 3 is connected to the pilot tunnel lower step side support steel frame 162, and the other end is connected to the first pilot tunnel main tunnel support 13.

[0039] Example 2 like Figure 4-13 As shown, a construction method for a double-hole single-track tunnel support structure with a clear distance of 0.2m-2m is used to form a double-hole single-track tunnel support structure with a clear distance of 0.2m-2m in Example 1, comprising: S1: Implement the construction steps of the first tunnel support structure; S2: Implement the construction steps of the second tunnel support structure; The construction steps for implementing the first tunnel support structure include: A1: Excavation of the first pilot tunnel upper bench: Excavate the pilot tunnel upper bench section 101 of the twin-hole single-track tunnel with a net distance greater than 0.2m and less than or equal to 2m. Expand the rock pillar area between the twin-hole single-track tunnels and install the pilot tunnel steel frame 16 and the pilot tunnel upper bench special-shaped steel frame 11. A2: Excavation of the first pilot tunnel step: Excavate the pilot tunnel step section 101 of the double-tunnel single-track tunnel with a net distance greater than 0.2m and less than or equal to 2m, and install the pilot tunnel step special-shaped steel frame 12, the pilot tunnel main tunnel support 13, and the first rear tunnel step reserved steel frame 21; A3: Excavation of the upper step of the first rear tunnel: Excavate the upper step section of the rear tunnel of the double-tunnel single-track tunnel section 101 with a net distance greater than 0.2m and less than or equal to 2m. When excavating to the special-shaped steel frame 11 of the upper step of the leading tunnel, install the main tunnel steel frame 22 of the upper step of the first rear tunnel, so that the main tunnel steel frame 22 of the upper step of the first rear tunnel is connected to the reserved steel frame 21 of the lower step of the first rear tunnel; A4: Casting the first concrete component 7: Cast the first concrete component 7 between the main tunnel support 13 of the leading tunnel and the reserved steel frame 21 at the lower step of the first rear tunnel; A5: Excavation of the first back-end tunnel step: After the excavation of the back-end tunnel step in the double-hole single-track tunnel section with a net distance greater than 0.2m and less than or equal to 2m is completed, the first back-end tunnel step steel frame 23 is installed on the side of the back-end tunnel away from the middle rock pillar; A6: Complete the installation of the first tunnel support structure: remove the special-shaped steel frame 12 under the step of the pilot tunnel; The construction steps for implementing the second tunnel support structure include: B1: Excavation of the second pilot tunnel upper step: Excavate the pilot tunnel upper step section of the double-hole single-track tunnel with a net distance of 0.2m in tunnel section 100, and install the pilot tunnel upper step main tunnel steel frame 14; B2: Excavation of the lower bench of the second pilot tunnel: Excavate the upper bench section of the pilot tunnel with a clear distance of 0.2m between the two-hole single-track tunnels. Expand the rock pillar area between the two-hole single-track tunnels. Install the main tunnel steel frame 15 of the lower bench of the pilot tunnel and the reserved steel frame 24 of the lower bench of the second rear tunnel. Connect the reserved steel frame 24 of the lower bench of the second rear tunnel to the main tunnel steel frame 15 of the lower bench of the pilot tunnel. B3: Excavation of the upper step of the second rear tunnel: Excavate the upper step section of the rear tunnel of the double-hole single-track tunnel with a net distance of 0.2m in the tunnel section 100. When excavating to the reserved steel frame 24 of the lower step of the second rear tunnel, install the main tunnel steel frame 25 of the upper step of the second rear tunnel and connect it with the reserved steel frame 24 of the lower step of the second rear tunnel; B4: Casting the second concrete member 8: Cast the second concrete member 8 between the reserved steel frame 24 at the lower step of the second rear tunnel and the main tunnel steel frame 15 at the lower step of the leading tunnel; B5: Excavation of the second back tunnel step: After the back tunnel step of the double-hole single-track tunnel section with a net distance of 0.2m is excavated, the second back tunnel step main tunnel steel frame 26 is installed on the side of the back tunnel away from the middle rock pillar.

[0040] First, the special-shaped cross-section excavation of the advance tunnel and the middle rock pillar range is carried out together, the middle rock pillar range is backfilled with concrete and the main tunnel support 13 of the advance tunnel is completed, and after the rear tunnel is excavated, it is connected to the rear tunnel steel frame reserved in the advance tunnel and the support is completed; thereby avoiding the problems of tunnel over-excavation and weak reinforcement and protection of the middle rock pillar; strong on-site practicality and high construction safety factor; improving the strength of the middle rock pillar range, providing good radial constraints for the support structure, and thus improving the stability of the middle rock pillar; using the micro-step method to construct the first tunnel support structure and the second tunnel support structure, so that the construction safety risk is effectively controlled, simplifying the construction process of double-hole single-line tunnels with a net distance of 0.2m-2m, improving construction efficiency, shortening construction period, and reducing risk construction time; by expanding the middle rock pillar and replacing it with concrete, the excavation volume is reduced, the excavation cost is reduced, the construction period is shortened, and the construction time cost is reduced.

[0041] In one or several embodiments, in A4, the first concrete component 7 fills the gap between the main tunnel support 13 of the pilot tunnel and the reserved steel frame 21 of the lower step of the first rear tunnel, and the top of the first concrete component 7 is connected to the special-shaped steel frame 11 of the upper step of the pilot tunnel.

[0042] In one or more embodiments, in B4, the first concrete component 7 fills the gap between the reserved steel frame 24 of the lower step of the second rear tunnel and the main tunnel steel frame 15 of the lower step of the advance tunnel.

[0043] In one or several embodiments, in A2, the special-shaped steel frame 12 of the lower step of the leading tunnel is installed close to the reserved steel frame 21 of the lower step of the first rear tunnel, and the reserved steel frame 21 of the lower step of the first rear tunnel is located on the side close to the middle rock column.

[0044] In one or several embodiments, in A2, before installing the special-shaped steel frame 12 of the lower step of the pilot tunnel, the main tunnel support 13 of the pilot tunnel and the reserved steel frame 21 of the lower step of the first rear tunnel, sprayed concrete is used to fill the expanded middle rock column range densely.

[0045] In one or more embodiments, in A2, the special-shaped steel frame 12 of the lower step of the pilot tunnel is connected to the special-shaped steel frame 11 of the upper step of the pilot tunnel by bolts.

[0046] In one or more embodiments, in A6, before removing the special-shaped steel frame 12 of the lower step of the leading tunnel, the lower step section of the first rear tunnel is excavated until the special-shaped steel frame 12 of the lower step of the leading tunnel is completely exposed in the rear tunnel 2.

[0047] The construction method of a double-hole single-line tunnel support structure with a clearance of 0.2m-2m of the present invention has the following advantages: 1. High on-site operability: The present invention first excavates the special-shaped sections of the pilot tunnel and the middle rock pillar area, and completes the sprayed concrete backfilling in the middle rock pillar area and the support of the pilot tunnel. After the rear tunnel is excavated, it is connected to the rear tunnel steel frame reserved in the pilot tunnel and the support is completed. Compared with the currently commonly used methods of reinforcing the middle rock pillars with tension anchor rods, radial grouting, etc. and then excavating the main tunnel with three steps or CD method, the construction method of the present invention does not need to consider the problems of over-excavation of the pilot tunnel and the rear tunnel and reinforcement and protection of the middle rock pillar. It has stronger on-site operability and makes up for the limitations of the current double-hole single-line tunnel construction method with a net distance of 0.2m-2m.

[0048] 2. Safety risks are controllable: The construction method of the present invention expands the middle rock pillars in the tunnel with a net distance of 0.2m-2m, adopts special-shaped steel frames for temporary support, and uses sprayed concrete to replace the broken rock mass, thereby improving the strength of the middle rock pillars and providing good radial constraints for the support structure, thereby improving the stability of the middle rock pillars. The construction method of the present invention can use large machines for micro-step construction, so that construction safety risks can be effectively controlled.

[0049] 3. High construction efficiency: The construction method of the present invention adopts conventional tunnel micro-step excavation. Compared with the currently used three-step seven-step method, CD method and small pilot tunnel method, the process is simpler and there is no need for grouting reinforcement of rock columns in the middle. It improves the construction efficiency of parallel single-line double-hole single-line tunnels, shortens the construction period, and reduces the risk construction time.

[0050] 4. Low construction cost: In addition to the main tunnel excavation range, this scheme increases the excavation of the middle rock pillar and uses shotcrete to replace the middle rock pillar. Compared with the central pilot tunnel method, which excavates the entire middle rock pillar, it reduces the excavation volume and lowers the excavation cost. Compared with conservative excavation methods such as the three-bench seven-step method and the CD method, it shortens the construction period and reduces the construction time cost.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A double-hole single-line tunnel support structure with a clear distance of 0.2m-2m, characterized in that: include: A plurality of first tunnel support structures and a plurality of second tunnel support structures are provided along the direction of the double-hole single-track tunnel, wherein a plurality of the first tunnel support structures are provided at intervals in tunnel sections (101) of the double-hole single-track tunnel with a net distance greater than 0.2 m and less than or equal to 2 m, and a plurality of the second tunnel support structures are provided at intervals in tunnel sections (100) of the double-hole single-track tunnel with a net distance of 0.2 m; The first tunnel support structure comprises a leading tunnel steel frame (16), a leading tunnel main tunnel support (13), a leading tunnel upper step special-shaped steel frame (11), a first rear tunnel lower step reserved steel frame (21), a first rear tunnel upper step main tunnel steel frame (22) and a first rear tunnel lower step main tunnel steel frame (23); the first leading tunnel steel frame (16) is connected to the leading tunnel main tunnel support (13) to form a first leading tunnel support structure, one end of the leading tunnel upper step special-shaped steel frame (11) is connected to the leading tunnel steel frame (16), and the other end is connected to the The first rear tunnel lower step reserved steel frame (21) is connected; the said leading tunnel upper step special-shaped steel frame (11) is connected to the end of the first rear tunnel upper step main tunnel steel frame (22); one end of the first rear tunnel upper step main tunnel steel frame (22) is connected to the first rear tunnel lower step reserved steel frame (21), and the other end is connected to the first rear tunnel lower step main tunnel steel frame (23), forming a first rear tunnel support structure, and a first concrete member (7) is provided between the said leading tunnel main tunnel support (13) and the first rear tunnel lower step reserved steel frame (21); The second tunnel support structure comprises a leading tunnel upper step main tunnel steel frame (14), a leading tunnel lower step main tunnel steel frame (15), a second rear tunnel lower step reserved steel frame (24), a second rear tunnel upper step main tunnel steel frame (25) and a second rear tunnel lower step main tunnel steel frame (26); both ends of the leading tunnel upper step main tunnel steel frame (14) are respectively connected to the leading tunnel lower step main tunnel steel frame (15) to form a second leading tunnel support structure; one end of the second rear tunnel upper step main tunnel steel frame (25) is connected to the second rear tunnel lower step The first end of the second rear tunnel is connected to the reserved steel frame (24) of the step, and the other end is connected to the main tunnel steel frame (26) of the lower step of the second rear tunnel, forming a second rear tunnel support structure; the main tunnel steel frame (15) of the lower step of the leading tunnel is connected to the main tunnel steel frame (25) of the second rear tunnel upper step, and the reserved steel frame (24) of the lower step of the second rear tunnel is connected to the main tunnel steel frame (14) of the upper step of the leading tunnel; a second concrete member (8) is provided between the reserved steel frame (24) of the lower step of the second rear tunnel and the main tunnel steel frame (15) of the lower step of the leading tunnel.

2. A double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 1, characterized in that: The leading tunnel steel frame (16) is further provided with a first leading tunnel inverted arch steel frame (3), one end of which is connected to the leading tunnel steel frame (16) and the other end is connected to the leading tunnel main tunnel support (13); the first trailing tunnel lower step reserved steel frame (21) is provided with a first trailing tunnel inverted arch steel frame (4), one end of which is connected to the first trailing tunnel lower step reserved steel frame (21) and the other end is connected to the first trailing tunnel lower step main tunnel steel frame (23).

3. The double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 1, characterized in that: The leading tunnel lower step main tunnel steel frame (15) is provided with a second leading tunnel inverted arch steel frame (5), and both ends of the second leading tunnel inverted arch steel frame (5) are respectively connected to the leading tunnel lower step main tunnel steel frame (15); the second rear tunnel lower step reserved steel frame (24) is provided with a second rear tunnel inverted arch steel frame (6), and one end of the second rear tunnel inverted arch steel frame (6) is connected to the second rear tunnel lower step reserved steel frame (24), and the other end is connected to the second rear tunnel lower step main tunnel steel frame (26).

4. A construction method for a double-hole single-track tunnel support structure with a clearance of 0.2m-2m, used to form a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to any one of claims 1-3, characterized in that: include: S1: Implement the construction steps of the first tunnel support structure; S2: Implement the construction steps of the second tunnel support structure; The construction steps of implementing the first tunnel support structure include: A1: Excavation of the first pilot tunnel upper step: Excavate the pilot tunnel upper step section of the double-hole single-track tunnel section (101) with a net distance greater than 0.2m and less than or equal to 2m, expand the rock pillar area between the double-hole single-track tunnels, and install the pilot tunnel steel frame (16) and the pilot tunnel upper step special-shaped steel frame (11); A2: Excavation of the first pilot tunnel step: Excavate the pilot tunnel step section of the double-tunnel single-line tunnel section (101) with a net distance greater than 0.2m and less than or equal to 2m, and install the pilot tunnel step special-shaped steel frame (12), the pilot tunnel main tunnel support (13) and the first rear tunnel step reserved steel frame (21); A3: Excavation of the first rear tunnel upper step: excavate the rear tunnel upper step section of the double-hole single-line tunnel section (101) with a net distance greater than 0.2m and less than or equal to 2m. When excavating to the special-shaped steel frame (11) of the leading tunnel upper step, install the first rear tunnel upper step main steel frame (22) so that the first rear tunnel upper step main steel frame (22) is connected to the first rear tunnel lower step reserved steel frame (21); A4: Casting the first concrete component (7): Casting the first concrete component (7) between the main tunnel support (13) of the leading tunnel and the reserved steel frame (21) at the lower step of the first rear tunnel; A5: Excavation of the first back tunnel step: After the excavation of the back tunnel step of the double-hole single-line tunnel section (101) with a net distance greater than 0.2m and less than or equal to 2m is completed, the first back tunnel step steel frame (23) is installed on the side of the back tunnel away from the middle rock pillar; A6: Complete the installation of the first tunnel support structure: remove the special-shaped steel frame (12) under the steps of the pilot tunnel; The construction steps of implementing the second tunnel support structure include: B1: Excavation of the second pilot tunnel upper step: excavate the pilot tunnel upper step section of the double-hole single-line tunnel with a net distance of 0.2m (100), and install the pilot tunnel upper step main tunnel steel frame (14); B2: Excavation of the second pilot tunnel lower step: excavate the pilot tunnel upper step section of the double-hole single-track tunnel section (100) with a net distance of 0.2m, expand the rock pillar area between the double-hole single-track tunnels, install the pilot tunnel lower step main steel frame (15) and the second rear tunnel lower step reserved steel frame (24), and connect the second rear tunnel lower step reserved steel frame (24) with the pilot tunnel lower step main steel frame (15); B3: Excavation of the upper step of the second rear tunnel: excavate the upper step section of the rear tunnel of the double-hole single-line tunnel with a net distance of 0.2m in the tunnel section (100). When the excavation reaches the reserved steel frame (24) of the lower step of the second rear tunnel, install the main tunnel steel frame (25) of the upper step of the second rear tunnel, so that the main tunnel steel frame (25) of the upper step of the second rear tunnel is connected to the reserved steel frame (24) of the lower step of the second rear tunnel; B4: Casting the second concrete member (8): Casting the second concrete member (8) between the reserved steel frame (24) at the lower step of the second rear tunnel and the main tunnel steel frame (15) at the lower step of the leading tunnel; B5: Excavation of the second back tunnel step: After the back tunnel step of the double-hole single-line tunnel section (100) with a net distance of 0.2m is excavated, the second back tunnel step main tunnel steel frame (26) is installed on the side of the back tunnel away from the middle rock column.

5. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the A4, the first concrete component (7) fills the gap between the main tunnel support (13) of the leading tunnel and the reserved steel frame (21) of the lower step of the first rear tunnel, and the top of the first concrete component (7) is connected to the special-shaped steel frame (11) of the upper step of the leading tunnel.

6. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the above-mentioned B4, the first concrete component (7) completely fills the gap between the reserved steel frame (24) of the lower step of the second rear tunnel and the main tunnel steel frame (15) of the lower step of the leading tunnel.

7. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the aforementioned A2, the special-shaped steel frame (12) of the step below the leading tunnel is installed close to the reserved steel frame (21) of the step below the first trailing tunnel, and the reserved steel frame (21) of the step below the first trailing tunnel is located on the side close to the middle rock column.

8. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the above-mentioned A2, before installing the special-shaped steel frame (12) of the lower step of the leading tunnel, the main tunnel support (13) of the leading tunnel and the reserved steel frame (21) of the lower step of the first rear tunnel, the expanded middle rock column range is sprayed and filled densely with sprayed concrete.

9. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the aforementioned A2, the special-shaped steel frame (12) of the lower step of the pilot hole and the special-shaped steel frame (11) of the upper step of the pilot hole are connected by bolts.

10. The construction method of a double-hole single-track tunnel support structure with a clearance of 0.2m-2m according to claim 4, characterized in that: In the above-mentioned A6, before removing the special-shaped steel frame (12) of the lower step of the leading tunnel, the first lower step section of the rear tunnel is excavated until the special-shaped steel frame (12) of the lower step of the leading tunnel is completely exposed in the rear tunnel (2).

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