Weak surrounding rock tunnel underground excavation construction method using pipe-roofing method

Abstract

The weak surrounding rock tunnel underground excavation construction method comprises the following steps that S1, working wells are formed in the positions, at the two ends of a tunnel to be excavated, of the ground, and the depth of the working wells is flush with the depth of the tunnel; s2, pipe roof structure construction is conducted on the periphery of the outline of the tunnel to be excavated through a pipe jacking machine; s3, grouting reinforcement is conducted on the outer side of the pipe curtain structure, so that a watertight space is formed by the outline of the tunnel to be excavated; s4, concrete is injected into the steel pipes of the pipe-roofing structure; and S5, after the concrete is solidified, the tunnel is excavated, and construction of a primary supporting structure is conducted. The pipe curtain structure and the supporting structure form a combined stress system, a large-rigidity ring longitudinal stress system capable of controlling ground surface settlement and avoiding underground water loss is formed, and the large-rigidity ring longitudinal stress system is suitable for projects such as shallow-buried large-section tunnels underneath passing urban existing roads or important buildings, urban subway stations under complex geological conditions and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of mined tunnel construction, and particularly relates to a mined tunnel construction method for soft surrounding rock using the pipe roof method. Background Art

[0002] With the increasing complexity of the underground engineering structure form and the gradual reduction of the distance from the surrounding existing structures, the traditional open cut method has brought adverse effects such as the relocation of municipal pipelines, the detour of surrounding traffic, dust and noise pollution, and the destruction of green landscapes during the construction of underground spaces, and is no longer applicable to the urban central areas with dense population and tight land use.

[0003] The pipe roof method is a method in which steel pipes are first jacked into the ground around the proposed underground building using pipe jacking technology, and the steel pipes are sealed with lock joints or the like to form a watertight underground space. Then, under the protection of the large-rigidity pipe roof, the soil within the range surrounded by the pipe roof is excavated and the main structure is cast. Since the pipe roof forms a large-rigidity temporary support structure, it can reduce the surface deformation caused by excavation and avoid affecting the surrounding buildings, and has incomparable advantages for projects with shallow buried large cross-section soft soil, dense buildings, and high environmental protection requirements.

[0004] In the traditional pipe roof advanced pre-support system, adjacent pipe roof steel pipes are usually connected by lock joints to form a protective water-stop curtain. However, most of the original lock joint forms are mainly L-shaped or I-shaped, and the pipe roof form is relatively single. When constructing an arc-shaped curtain structure, this method is easily affected by external forces, resulting in a reduction in the overall strength; and simply connecting with lock joints cannot effectively form a continuous pipe shed water-stop curtain, and the waterproof performance is lacking. Summary of the Invention

[0005] The purpose of the present invention is to provide a mined tunnel construction method for soft surrounding rock using the pipe roof method to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides a mined tunnel construction method for soft surrounding rock using the pipe roof method, including the following steps:

[0007] S1. Open working shafts on the ground at both ends of the tunnel to be excavated, and the depth of the working shafts is flush with the depth of the tunnel;

[0008] S2. Use a pipe jacking machine to construct a pipe roof structure around the contour of the tunnel to be excavated;

[0009] S3. Grout and reinforce the outside of the pipe roof structure to form a watertight space for the contour of the tunnel to be excavated;

[0010] S4. Inject concrete into the steel pipes of the pipe roof structure;

[0011] S5. After the concrete solidifies, excavate the tunnel and construct the primary support structure.

[0012] Preferably, the grouting reinforcement uses cement slurry, and the grouting pressure is controlled at 0.5 Mpa to 1 Mpa.

[0013] Preferably, the primary support structure uses a circumferential steel arch, and the circumferential steel arch is fixedly welded to the pipe roof structure.

[0014] Preferably, an internal temporary support structure is provided inside the circumferential steel arch.

[0015] Preferably, a set of the internal temporary support structures is provided for every two circumferential steel arches.

[0016] Preferably, the internal temporary support structure is a jack.

[0017] The present invention provides a pipe roof structure, which is applied to the above-mentioned method for the concealed excavation construction of a soft surrounding rock tunnel using the pipe roof method, and specifically includes a plurality of parallel steel pipes and a connection structure for connecting two adjacent steel pipes;

[0018] The connection structure includes a first connection buckle and a second connection buckle respectively arranged on the outer wall of the steel pipe, and the first connection buckle and the second connection buckle are respectively arranged on opposite sides of the steel pipe; both the first connection buckle and the second connection buckle are arc-shaped structures, and the outer wall of the first connection buckle is in contact and cooperation with the inner wall of the second connection buckle; a grouting conduit is arranged at the connection of the steel pipe and the second connection buckle, and the grouting conduit is located outside the second connection buckle;

[0019] A female lock buckle is installed on the inner wall of the first connection buckle, and a male lock buckle is installed on the inner wall of the second connection buckle, and the female lock buckle and the male lock buckle are arranged correspondingly.

[0020] Preferably, the diameter of the steel pipe is 200 - 300 mm.

[0021] Preferably, the central angles corresponding to the first connection buckle and the second connection buckle are not less than 270°.

[0022] Preferably, the female lock buckle includes a connection card slot and a guide channel fixedly connected to the inner wall of the first connection buckle, and the connection card slot and the guide channel are arranged correspondingly;

[0023] The public lock includes an arc-shaped mounting plate. An arc-shaped mounting groove is formed on the inner wall of the second connection buckle, and the arc-shaped mounting plate is detachably mounted in the arc-shaped mounting groove. A connecting plate is fixedly connected to the arc-shaped mounting plate. One end of the connecting plate away from the arc-shaped mounting plate is hinged with a connecting head through a hinge shaft. The connecting head passes through the guiding channel and is adapted to the connection card slot. The hinge shaft is coaxially arranged with the second connection buckle.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] 1. The method for the concealed excavation construction of a soft surrounding rock tunnel using the pipe roof method provided by the present invention forms a combined stress system through the pipe roof structure and the support structure, forming a large-rigidity ring longitudinal stress system that can control the ground settlement and avoid groundwater loss. It is applicable to projects such as shallow-buried large-section tunnels passing under existing urban roads or important buildings, and urban subway stations under complex geological conditions.

[0026] 2. The pipe roof structure provided by the present invention connects two steel pipes through the first connection buckle and the second connection buckle welded externally to form a unified whole, improving the bearing capacity of the pipe roof, reducing the danger during the construction process, and improving the stability of the pipe roof structure. Moreover, both the first connection buckle and the second connection buckle are arc-shaped structures, which can realize the angle adjustment between the pipe roof steel pipes. Through the setting of the grouting conduit, the soil outside the pipe roof structure can be reinforced to prevent the soil from collapsing during construction and improve the overall airtightness of the pipe roof structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a connection schematic diagram when the pipe roof structures of the present invention are horizontally connected;

[0029] Figure 2 It is a connection schematic diagram when the pipe roof structures of the present invention are connected with an inclination angle;

[0030] In the figure: 1. Steel pipe; 2. First connection buckle; 3. Second connection buckle; 4. Grouting conduit; 5. Connection card slot; 6. Guiding channel; 7. Arc-shaped mounting plate; 8. Arc-shaped mounting groove; 9. Connecting plate; 10. Hinge shaft; 11. Connecting head. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] As Figures 1 to 2 shown, the present invention provides a method for the concealed excavation construction of a soft surrounding rock tunnel using the pipe roof method, including the following steps:

[0033] S1. Open working shafts on the ground at both ends of the tunnel to be excavated, and the depth of the working shafts is flush with the depth of the tunnel;

[0034] S2. Use a pipe jacking machine to construct a pipe roof structure around the contour of the tunnel to be excavated;

[0035] S3. Grout and reinforce the outside of the pipe roof structure to form a watertight space for the contour of the tunnel to be excavated;

[0036] S4. Inject concrete into the steel pipe 1 of the pipe roof structure;

[0037] S5. After the concrete solidifies, excavate the tunnel and construct the primary support structure.

[0038] The present invention forms a combined force-bearing system composed of a pipe roof structure and a support structure, and forms a large-rigidity ring longitudinal force-bearing system that can control ground settlement and avoid groundwater loss, and is applicable to projects such as shallow-buried large-section tunnels passing under existing urban roads or important buildings, and urban subway stations under complex geological conditions.

[0039] In a further optimized solution, the grouting reinforcement uses cement slurry, and the grouting pressure is controlled at 0.5 Mpa to 1 Mpa.

[0040] In a further optimized solution, the primary support structure uses a circumferential steel arch, and the circumferential steel arch is welded and fixed to the pipe roof structure.

[0041] In a further optimized solution, an internal temporary support structure is provided inside the circumferential steel arch.

[0042] In a further optimized solution, a group of internal temporary support structures is provided for every two circumferential steel arches.

[0043] In a further optimized solution, the internal temporary support structure is a jack.

[0044] The present invention provides a pipe roof structure, which is applied to the method for the concealed excavation construction of a soft surrounding rock tunnel using the pipe roof method as described above, and specifically includes a plurality of steel pipes 1 arranged in parallel and a connection structure for connecting two adjacent steel pipes 1;

[0045] The connecting structure includes a first connecting buckle 2 and a second connecting buckle 3 respectively arranged on the outer wall of the steel pipe 1, and the first connecting buckle 2 and the second connecting buckle 3 are respectively arranged on opposite sides of the steel pipe 1; both the first connecting buckle 2 and the second connecting buckle 3 are arc-shaped structures, and the outer wall of the first connecting buckle 2 is in contact and cooperation with the inner wall of the second connecting buckle 3; a grouting conduit 4 is arranged at the connection between the steel pipe 1 and the second connecting buckle 3, and the grouting conduit 4 is located outside the second connecting buckle 3;

[0046] A female locking buckle is installed on the inner wall of the first connecting buckle 2, and a male locking buckle is installed on the inner wall of the second connecting buckle 3, and the female locking buckle and the male locking buckle are arranged correspondingly.

[0047] In the present invention, the two steel pipes 1 are connected by the externally welded first connecting buckle 2 and second connecting buckle 3 to form a unified whole, improving the bearing capacity of the pipe roof, reducing the danger during the construction process, and improving the stability of the pipe roof structure. Moreover, both the first connecting buckle 2 and the second connecting buckle 3 are arc-shaped structures, which can realize the angle adjustment between the pipe roof steel pipes 1. Through the arrangement of the grouting conduit 4, the soil outside the pipe roof structure can be reinforced to prevent the soil from collapsing during construction and improve the overall tightness of the pipe roof structure.

[0048] In a further optimized scheme, the diameter of the steel pipe 1 is 200 - 300 mm.

[0049] In a further optimized scheme, the central angles corresponding to the first connecting buckle 2 and the second connecting buckle 3 are not less than 270°.

[0050] In a further optimized scheme, the female locking buckle includes a connection card slot 5 and a guiding channel 6 fixedly connected to the inner wall of the first connecting buckle 2, and the connection card slot 5 and the guiding channel 6 are arranged correspondingly;

[0051] The male locking buckle includes an arc-shaped mounting plate 7, an arc-shaped mounting groove 8 is formed on the inner wall of the second connecting buckle 3, and the arc-shaped mounting plate 7 is detachably mounted in the arc-shaped mounting groove 8; a connecting plate 9 is fixedly connected to the arc-shaped mounting plate 7, and one end of the connecting plate 9 away from the arc-shaped mounting plate 7 is hinged with a connecting head 11 through a hinge shaft 10, and the connecting head 11 passes through the guiding channel 6 and is adapted to the connection card slot 5; the hinge shaft 10 is coaxially arranged with the second connecting buckle 3.

[0052] When the pipe roof structure provided by the present invention works, the first connecting buckle 2, the second connecting buckle 3 and the grouting conduit 4 are respectively welded to the steel pipe 1, and then the male locking buckle is installed on the inner wall of the second connecting buckle 3 according to the installation angle between the two steel pipes 1.

[0053] When constructing the pipe curtain structure, a steel pipe 1 is first jacked in by a pipe jacking machine as the initial pipe curtain. The first connection buckle 2 and the second connection buckle 3 on the steel pipe 1 play a guiding role. Then, other steel pipes 1 are successively jacked in on both sides of the initial pipe curtain in the occluding direction until a closed pipe curtain is formed. When connecting two adjacent steel pipes 1, the outer wall of the first connection buckle 2 contacts the inner wall of the second connection buckle 3. At the same time, according to the angle requirement between the two steel pipes 1, the connector 11 is rotated around the hinge axis 10. When connecting, the connector 11 is clamped into the guiding channel 6 and the connection slot 5, and the angle adjustment between the steel pipes 1 can be realized.

[0054] After the jacking process is completed, grouting reinforcement is carried out on the soil outside the pipe curtain, and the cavity formed by the first connection buckle 2 and the second connection buckle 3 is filled with grout to form two layers of internal and external protection, forming a continuous water-stop curtain, improving the tightness of the pipe curtain structure, and effectively preventing soil collapse and water flow penetration.

[0055] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for dark excavation of soft surrounding rock tunnels using a pipe-roof method, characterized in that: The following steps are involved: S1. Open working wells on the ground at both ends of the tunnel to be excavated, and the depth of the working wells is flush with the depth of the tunnel; S2. Use a pipe jacking machine to construct a pipe curtain structure around the outline of the tunnel to be excavated; S3. Grouting reinforcement is performed on the outer side of the pipe curtain structure to form a watertight space in the outline of the tunnel to be excavated; S4, injecting concrete into the steel pipe (1) of the pipe-roof structure; S5. After the concrete solidifies, the tunnel is excavated and the primary support structure is constructed.

2. The method for dark excavation of soft surrounding rock tunnels using the pipe-roof method according to claim 1 is characterized in that: The grouting reinforcement uses cement slurry, and the grouting pressure is controlled at 0.5Mpa to 1Mpa.

3. The method for dark excavation of a soft surrounding rock tunnel using the pipe-roof method according to claim 1 is characterized in that: The primary support structure adopts an annular steel arch frame, and the annular steel arch frame is welded and fixed to the pipe-roof structure.

4. The method for dark excavation of a soft surrounding rock tunnel using the pipe-roof method according to claim 3 is characterized in that: An internal temporary supporting structure is arranged inside the annular steel arch.

5. The method for dark excavation of a soft surrounding rock tunnel using the pipe-roof method according to claim 4 is characterized in that: A group of internal temporary supporting structures is arranged every two sections of the annular steel arches.

6. The method for dark excavation of a soft surrounding rock tunnel using the pipe-roof method according to claim 5 is characterized in that: The internal temporary supporting structure is a jack.

7. A pipe-roof structure, applied to the method for dark excavation of a soft surrounding rock tunnel using the pipe-roof method as claimed in claim 1, characterized in that: It comprises a plurality of steel pipes (1) arranged in parallel and a connecting structure for connecting two adjacent steel pipes (1); The connection structure comprises a first connection buckle (2) and a second connection buckle (3) respectively arranged on the outer wall of the steel pipe (1), and the first connection buckle (2) and the second connection buckle (3) are respectively arranged on two opposite sides of the steel pipe (1); the first connection buckle (2) and the second connection buckle (3) are both arc-shaped structures, and the outer wall of the first connection buckle (2) is in contact with the inner wall of the second connection buckle (3); a grouting conduit (4) is arranged at the connection between the steel pipe (1) and the second connection buckle (3), and the grouting conduit (4) is located on the outer side of the second connection buckle (3); A female lock buckle is installed on the inner wall of the first connecting buckle (2), and a male lock buckle is installed on the inner wall of the second connecting buckle (3), and the female lock buckle is arranged correspondingly to the female lock buckle.

8. The tube roof structure according to claim 7, characterized in that: The diameter of the steel pipe (1) is 200-300 mm.

9. The tube roof structure according to claim 7, characterized in that: The central angle corresponding to the first connecting buckle (2) and the second connecting buckle (3) is not less than 270°.

10. The tube roof structure according to claim 7, characterized in that: The female lock buckle comprises a connection slot (5) and a guide channel (6) fixedly connected to the inner wall of the first connection buckle (2), and the connection slot (5) and the guide channel (6) are arranged correspondingly; The male lock buckle comprises an arc-shaped mounting plate (7), an arc-shaped mounting groove (8) is provided on the inner wall of the second connecting buckle (3), and the arc-shaped mounting plate (7) can be detachably mounted in the arc-shaped mounting groove (8); a connecting plate (9) is fixedly connected to the arc-shaped mounting plate (7), and an end of the connecting plate (9) away from the arc-shaped mounting plate (7) is hinged with a connecting head (11) through a hinge shaft (10), and the connecting head (11) passes through the guide channel (6) and is adapted to the connecting slot (5); the hinge shaft (10) and the second connecting buckle (3) are coaxially arranged.

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