Rapid out-of-hole construction method for shallow-buried unsymmetrical-pressure extra-large-span tunnel

Abstract

The invention discloses a shallow-buried unsymmetrical-pressure extra-large-span tunnel rapid out-of-hole construction method which divides a tunnel into a first part, a second part and a third part on the upper portion and a fourth part, a fifth part and a sixth part on the lower portion in the section direction and comprises the following steps that S1, a top hole of the first part is constructed till the top hole is through; s2, constructing a second part on the left side and a third part on the right side of the upper step; s3, four parts of the left side and five parts of the right side of the lower step are constructed; s4, six-part core soil is constructed, and six tunnel faces are required to be lagged behind five parts by 10-15 m; s5, pouring an inverted arch and filling concrete, pouring the inverted arch and the filling layer by layer, and performing left-right one-time forming; and S6, according to analysis of the monitoring measurement result, after the primary support is converged, the arch wall lining is poured at a time through the lining formwork jumber.According to the construction method, the mode that one top hole comes out of the hole first, and a construction road is opened is adopted, the material transportation pressure of a hole opening area is greatly relieved, and the material transportation cost is reduced to a certain degree.

Description

Technical Field

[0001] The present invention relates to the field of tunnel rapid exit construction methods, and more specifically, to a shallow buried biased extra-large span tunnel rapid exit construction method. Background Art

[0002] With the goal of building a strong transportation nation, more and more transportation infrastructure is advancing to the western mountainous areas. The western mountainous areas often have complex geological conditions, with many mountain canyons and frequent bridge and tunnel connections. The technical difficulty and construction organization at the tunnel entrance where the bridge and tunnel are connected face great challenges. On the one hand, the slope of the bridge site is steep, and there is a lack of traffic conditions for the bridge construction. It is urgent to quickly exit the tunnel and open up the construction road in the bridge area; on the other hand, the entrance area of ​​the extra-large span tunnel is shallowly buried, greatly affected by weathering and erosion, and the surrounding rock is poor. The construction safety risk is high, the technical difficulty is high, and it is very easy to cause disasters such as landslides and large deformations. In order to ensure construction safety, it is also necessary to quickly exit the tunnel. Summary of the invention

[0003] In order to achieve these purposes and other advantages according to the present invention, a preferred embodiment of the present invention provides a shallow-buried biased large-span tunnel rapid exit construction method, the tunnel is divided into an upper first part, a second part, a third part and a lower fourth part, a fifth part, and a sixth part along the cross-sectional direction, and the first part, the second part, and the third part are arranged in sequence from left to right, and the fourth part, the fifth part, and the sixth part are arranged in sequence from left to right. The shallow-buried biased large-span tunnel rapid exit construction method comprises the following steps:

[0004] S1. Construct a top hole until it is through, and replace the road with a tunnel;

[0005] S2, construct the second part on the left side of the upper step and the third part on the right side, and during the construction process, the second part's face is required to be 5m ahead of the third part's face;

[0006] S3, construct the fourth section on the left side of the lower step and the fifth section on the right side, and during the construction process, the fourth section's face is required to lag behind the second section by 10-15m, and the fifth section's face is required to lag behind the third section by 30m;

[0007] S4: Construction of the core soil of the sixth section requires that the sixth section’s face lags behind the fifth section by 10-15m;

[0008] S5, pouring the invert and filling concrete, the invert and filling are poured in layers, and the left and right sides are formed at one time;

[0009] S6. According to the analysis of monitoring and measurement results, after the initial support converges, the arch wall lining is poured in one go using the lining formwork trolley.

[0010] Preferably, in S2, a slag window is opened at the first vertical support every 30m to provide slag discharge for the second and third parts, and personnel and equipment can be transported from the slag window to the tunnel face to achieve parallel operation of various parts.

[0011] Preferably, the S1 specifically comprises the following steps:

[0012] S11, carry out advanced support for the top hole;

[0013] S12. Use weak blasting or mechanical excavation to dig a part of the top hole. At the same time, spray 5cm thick concrete to seal the tunnel face after each cycle.

[0014] S13, carry out initial support around the top hole in steps;

[0015] S14. The arch part of the first part is sprayed with concrete for the second time according to the design thickness requirements, covering the steel frame, and marking the positions of the shell expansion anchor rods, prestressed anchor rods, and prestressed anchor cables corresponding to the first part;

[0016] S15. After the construction of the tunnel face is completed, insert the shell anchor rod into the arch part of the top hole of the first part; after the first part is penetrated, install the prestressed anchor rod and prestressed anchor cable corresponding to the first part, inject grout into the shell anchor rod, prestressed anchor rod and prestressed anchor cable, and after the grouting is strong, tension it to the designed tension for locking;

[0017] S16. Carry out the third spraying of concrete on the top hole arch part and cover it with steel mesh. Re-spray it to the designed thickness to ensure that the concrete covers the ends of prestressed anchor rods and prestressed anchor cable anchors.

[0018] Preferably, in S13, initial support around a portion of the top hole is implemented step by step, specifically including the following steps: initial spraying of 5 cm thick concrete, installation of initial support steel frame, and installation of locking foot anchor pipes.

[0019] Preferably, the step S2 specifically includes the following steps:

[0020] S21. After the first section is penetrated and the initial support is completed, advance support for the second and third arch sections is carried out;

[0021] S22, weak blasting or mechanical excavation construction parts 2 and 3;

[0022] S23, carry out initial support around the second and third parts in stages;

[0023] S24, the second and third pilot tunnel arch parts are sprayed with concrete for the second time according to the design thickness requirements, covering the steel frame, and marking the positions of the expansion anchor rods, prestressed anchor rods and prestressed anchor cables corresponding to the second and third parts;

[0024] S25, the second and third arch shell anchors are installed closely following the tunnel face;

[0025] S26: Prestressed anchor rods and prestressed anchor cables are installed 30m behind the tunnel face. After grouting and strengthening, they are tensioned to the designed tension and locked;

[0026] S27, spray concrete for the third time on the second and third top hole arch parts, cover the steel mesh, spray again to the designed thickness, and cover the prestressed anchor rod ends and prestressed anchor cable end anchors;

[0027] During the construction process, the third part lagged behind the second part by 5m.

[0028] Preferably, S23, performing initial support around the second part in steps, specifically comprises the following steps:

[0029] Initially spray 5cm thick concrete, set up the steel frame to connect with the arch steel frame, and install the locking anchor pipe.

[0030] Preferably, the step S3 specifically includes the following steps:

[0031] S31, respectively carry out advanced support for the fourth and fifth arches;

[0032] S32, weak blasting or mechanical excavation construction parts 4 and 5;

[0033] S33, carry out initial support around the four parts in steps, i.e. spray 5cm thick concrete, set up steel frame to connect with the arch steel frame, and install locking anchor pipe;

[0034] S34, spray the side walls of the four pilot pits with the second concrete according to the design thickness requirements, cover the steel frame, and mark the positions of the 2 expansion shell anchors, prestressed anchors, and prestressed anchor cables;

[0035] S35, the shell expansion anchors of the four side walls are installed closely following the tunnel face;

[0036] S36, 30m behind the tunnel face, install prestressed anchor rods and prestressed anchor cables, grouting and other strength, tension to the designed tension for locking;

[0037] S37, spray concrete for the third time on the arch of the five side walls, lay steel mesh, and spray again to the designed thickness to cover the end of the prestressed anchor rod and the end of the prestressed anchor cable;

[0038] In addition, during the construction process, core soil of the middle step is reserved, the fifth section lags behind the third section by 30m, the fourth section lags behind the second section by 30m, and the fifth section's heading surface lags behind the fourth section's heading surface by 5m.

[0039] Preferably, the S4 specifically comprises the following steps:

[0040] S41. Use weak blasting or mechanical excavation to excavate the six core soils and the corresponding lower inverts and apply initial support, 30m behind the fifth part. Use weak blasting or mechanical excavation to excavate the six core soils and the corresponding lower inverts and apply initial support.

[0041] S42, reserve six 15% ramps.

[0042] The present invention includes at least the following beneficial effects: The present invention aims to provide a method for rapid exit construction of a shallow-buried, biased, large-span tunnel, to solve the difficult problems of high safety risk and slow construction speed in the exit of extra-large-span tunnels. On the one hand, it can effectively standardize on-site operations and improve the quality of tunnel construction; on the other hand, it can improve construction efficiency and achieve cost reduction and efficiency improvement in tunnel production.

[0043] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The process flow chart of the shallow buried biased extra-large span tunnel quick exit construction method of the present invention;

[0045] Figure 2 It is a schematic diagram of the parts of the tunnel face of the present invention;

[0046] Figure 3 It is a schematic diagram of the tunnel face support structure of the present invention;

[0047] Figure 4 It is a schematic diagram of the arrangement of the locking pins of the present invention;

[0048] Figure 5 It is a schematic diagram of the step distance of each part of the present invention;

[0049] 1-Advance support; 2-Expansion shell anchor rod; 3-Initial support of the main tunnel; 4-Part of temporary vertical support; 5-Prestressed anchor rod; 6-Prestressed anchor cable; 7-Lock-foot anchor pipe. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0051] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0052] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0053] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0054] like Figure 1-5 As shown, a preferred embodiment of the present invention provides a shallow-buried biased extra-large span tunnel rapid exit construction method, the tunnel is divided into an upper first section (① section), a second section (② section), a third section (③ section) and a lower fourth section (④ section), a fifth section (⑤ section), and a sixth section (⑥ section) along the cross-sectional direction, and the first section, the second section, and the third section are arranged in sequence from left to right, and the fourth section, the fifth section, and the sixth section are arranged in sequence from left to right. The shallow-buried biased extra-large span tunnel rapid exit construction method comprises the following steps:

[0055] S1. Construct a top hole until it is through, and replace the road with a tunnel;

[0056] S11, carry out top hole advance support 1;

[0057] S12. Use weak blasting or mechanical excavation to dig a part of the top hole. At the same time, spray 5cm thick concrete to seal the tunnel face after each cycle.

[0058] S13, carry out the initial support 3 around the top hole in steps, i.e. spray 5 cm thick concrete, install the initial support steel frame, and install the locking anchor pipe;

[0059] S14, spray the second concrete on the arch part of the first part according to the design thickness requirements, cover the steel frame, set a temporary vertical support 4 on the first part, and mark the positions of the shell expansion anchor 2, prestressed anchor 5, and prestressed anchor cable 6 corresponding to the first part respectively;

[0060] S15, after the construction of the tunnel face is completed, insert the shell anchor 2 into the arch part of the top hole; after the first part is penetrated, install the prestressed anchor 5 and prestressed anchor cable 6 corresponding to the first part, inject grout into the shell anchor 2, prestressed anchor 5 and prestressed anchor cable 6, and after the grouting is strong, tension it to the designed tension for locking;

[0061] S16. Carry out the third spraying of concrete on the top hole arch part and cover it with steel mesh. Re-spray it to the designed thickness to ensure that the concrete covers the ends of prestressed anchor rods and prestressed anchor cable anchors.

[0062] S2, construct the second part on the left side of the upper step and the third part on the right side, and during the construction process, the second part's heading face is required to be 5m ahead of the third part's heading face; in S2, slag windows are opened at the first vertical support every 30m to provide slag discharge for the second and third parts, and at the same time, personnel and equipment can be transported from the slag windows to the heading face to achieve parallel operation of various parts.

[0063] S21. After the first section is penetrated and the initial support is completed, advance support 1 of the second and third arch sections is carried out;

[0064] S22, weak blasting or mechanical excavation construction parts 2 and 3;

[0065] S23, carry out initial support 3 around the second and third parts in steps, that is, spray 5 cm thick concrete, set up a steel frame to connect with the arch steel frame, and install locking foot anchor pipe 7.

[0066] S24, the second and third pilot pit arch parts are sprayed with a second concrete according to the design thickness requirements, covering the steel frame, and marking the positions of the shell anchor rod 2, prestressed anchor rod 5, and prestressed anchor cable 6 corresponding to the second and third parts;

[0067] S25, the second and third arch 2 shell anchor bolts are installed closely following the tunnel face;

[0068] S26, prestressed anchor rods 5 and prestressed anchor cables 6 are installed 30m behind the tunnel face. After grouting and equal strength, they are tensioned to the designed tension and locked;

[0069] S27, spray concrete for the third time on the second and third top hole arch parts, cover the steel mesh, spray again to the designed thickness, and cover the prestressed anchor rod ends and prestressed anchor cable end anchors;

[0070] During the construction process, the third part lagged behind the second part by 5m. And the temporary vertical support of the first part was removed by 4.

[0071] S3, construct the fourth section on the left side of the lower step and the fifth section on the right side, and during the construction process, the fourth section's face is required to lag behind the second section by 10-15m, and the fifth section's face is required to lag behind the third section by 30m;

[0072] S31, respectively carry out advanced support 1 for the fourth and fifth arches;

[0073] S32, weak blasting or mechanical excavation construction parts 4 and 5;

[0074] S33, carry out initial support 3 around the four parts in steps, i.e. spray 5 cm thick concrete, set up steel frame to connect with the arch steel frame, and install locking anchor pipe;

[0075] S34, spray the side walls of the four pilot pits with the second concrete according to the design thickness requirements, cover the steel frame, and mark the positions of 2 shell anchor rods, 5 prestressed anchor rods, and 6 prestressed anchor cables;

[0076] S35, the shell expansion anchors of the four side walls are installed closely following the tunnel face;

[0077] S36, 30m behind the tunnel face, 5 prestressed anchor rods and 6 prestressed anchor cables are installed, and after grouting, they are tensioned to the designed tension for locking;

[0078] S37, spray concrete for the third time on the arch of the five side walls, lay steel mesh, and spray again to the designed thickness to cover the end of the prestressed anchor rod and the end of the prestressed anchor cable;

[0079] In addition, during the construction process, core soil of the middle step is reserved, the fifth section lags behind the third section by 30m, the fourth section lags behind the second section by 30m, and the fifth section's heading surface lags behind the fourth section's heading surface by 5m.

[0080] S4: Construction of the core soil of the sixth section requires that the sixth section’s face lags behind the fifth section by 10-15m;

[0081] S41. Use weak blasting or mechanical excavation to excavate the six core soils and the corresponding lower inverts and apply initial support 3, lag five by 30m, use weak blasting or mechanical excavation to excavate the six core soils and the corresponding lower inverts and apply initial support 3.

[0082] S42, reserve six 15% ramps (about 35m).

[0083] S5, pouring the invert and filling concrete, the invert and filling are poured in layers, and the left and right sides are formed at one time;

[0084] S6. According to the analysis of monitoring and measurement results, after the initial support converges, the arch wall lining is poured in one go using the lining formwork trolley.

[0085] The present invention provides a method for rapid exit construction of a shallow-buried, biased, large-span tunnel, which solves the difficult problems of high safety risk and slow construction speed in the exit of an extra-large-span tunnel. On the one hand, it effectively standardizes on-site operations and improves the quality of tunnel construction. On the other hand, it can improve construction efficiency and achieve cost reduction and efficiency improvement in tunnel production.

[0086] The construction method of the present invention adopts a method of first exiting the cave with one part of the top hole, thus opening up the construction road, greatly alleviating the material transportation pressure in the cave entrance area and reducing the material transportation cost to a certain extent.

[0087] Compared with other construction methods applicable to 23m large-span tunnels, such as the double-side wall pilot pit method and the CD method, the construction method of the present invention simplifies the construction process and improves the construction efficiency while ensuring construction safety.

[0088] In another technical solution, in S13, the initial support 3 around the top hole is implemented step by step, specifically including the following steps:

[0089] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for rapid exit construction of a shallow-buried bias-pressure extra-large-span tunnel, characterized in that: The tunnel is divided into the first, second and third parts at the top and the fourth, fifth and sixth parts at the bottom along the cross-sectional direction, and the first, second and third parts are arranged in sequence from left to right, and the fourth, fifth and sixth parts are arranged in sequence from left to right. The shallow buried biased super-large span tunnel rapid exit construction method comprises the following steps: S1. Construct a top hole until it is through, and replace the road with a tunnel; S2, construct the second part on the left side of the upper step and the third part on the right side, and during the construction process, the second part's face is required to be 5m ahead of the third part's face; S3, construct the fourth section on the left side of the lower step and the fifth section on the right side, and during the construction process, the fourth section's face is required to lag behind the second section by 10-15m, and the fifth section's face is required to lag behind the third section by 30m; S4: Construction of the core soil of the sixth section requires that the sixth section’s face lags behind the fifth section by 10-15m; S5, pouring the invert and filling concrete, the invert and filling are poured in layers, and the left and right sides are formed at one time; S6. According to the analysis of monitoring and measurement results, after the initial support converges, the arch wall lining is poured in one go using the lining formwork trolley.

2. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 1 is characterized in that: In S2, slag windows are opened at the first vertical support every 30m to provide slag discharge for the second and third parts. At the same time, personnel and equipment can be transported to the face through the slag windows to achieve parallel operation of various parts.

3. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 1 is characterized in that: The S1 specifically comprises the following steps: S11, carry out advanced support for the top hole; S12. Use weak blasting or mechanical excavation to dig a part of the top hole. At the same time, spray 5cm thick concrete to seal the tunnel face after each cycle. S13, carry out initial support around the top hole in steps; S14. The arch part of the first part is sprayed with concrete for the second time according to the design thickness requirements, covering the steel frame, and marking the positions of the shell expansion anchor rods, prestressed anchor rods, and prestressed anchor cables corresponding to the first part; S15. After the construction of the tunnel face is completed, insert the shell anchor rod into the arch part of the top hole of the first part; after the first part is penetrated, install the prestressed anchor rod and prestressed anchor cable corresponding to the first part, inject grout into the shell anchor rod, prestressed anchor rod and prestressed anchor cable, and after the grouting is strong, tension it to the designed tension for locking; S16. Carry out the third spraying of concrete on the top hole arch part and cover it with steel mesh. Re-spray it to the designed thickness to ensure that the concrete covers the ends of prestressed anchor rods and prestressed anchor cable anchors.

4. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 3 is characterized in that: In S13, the initial support around the top hole is carried out step by step, including the following steps: initial spraying of 5 cm thick concrete, installation of initial support steel frame, and installation of locking anchor pipes.

5. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 1 is characterized in that: The S2 specifically includes the following steps: S21. After the first section is penetrated and the initial support is completed, advance support for the second and third arch sections is carried out; S22, weak blasting or mechanical excavation construction parts 2 and 3; S23, carry out initial support around the second and third parts in stages; S24, the second and third pilot tunnel arch parts are sprayed with concrete for the second time according to the design thickness requirements, covering the steel frame, and marking the positions of the expansion anchor rods, prestressed anchor rods and prestressed anchor cables corresponding to the second and third parts; S25, the second and third arch shell anchors are installed closely following the tunnel face; S26: Prestressed anchor rods and prestressed anchor cables are installed 30m behind the tunnel face. After grouting and strengthening, they are tensioned to the designed tension and locked; S27, spray concrete for the third time on the second and third top hole arch parts, cover the steel mesh, spray again to the designed thickness, and cover the prestressed anchor rod end and prestressed anchor cable end anchor; During the construction process, the third part lagged behind the second part by 5m.

6. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 5 is characterized in that: S23: Carry out the initial support around the second part in steps, including the following steps: Initially spray 5cm thick concrete, set up the steel frame to connect with the arch steel frame, and install the locking anchor pipe.

7. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 5 is characterized in that: The S3 specifically includes the following steps: S31, respectively carry out advanced support for the fourth and fifth arches; S32, weak blasting or mechanical excavation construction parts 4 and 5; S33, carry out initial support around the four parts in steps, i.e. spray 5cm thick concrete, set up steel frame to connect with the arch steel frame, and install locking anchor pipe; S34, spray the side walls of the four pilot pits with the second concrete according to the design thickness requirements, cover the steel frame, and mark the positions of the 2 expansion shell anchors, prestressed anchors, and prestressed anchor cables; S35, the shell expansion anchors of the four side walls are installed closely following the tunnel face; S36, 30m behind the tunnel face, install prestressed anchor rods and prestressed anchor cables, grouting and other strength, tension to the designed tension for locking; S37, spray concrete for the third time on the arch of the five side walls, lay steel mesh, and spray again to the designed thickness to cover the end of the prestressed anchor rod and the end of the prestressed anchor cable; In addition, during the construction process, core soil of the middle step is reserved, the fifth section lags behind the third section by 30m, the fourth section lags behind the second section by 30m, and the fifth section's heading surface lags behind the fourth section's heading surface by 5m.

8. The method for rapid exit construction of a shallow-buried biased extra-large-span tunnel according to claim 7 is characterized in that: The S4 specifically comprises the following steps: S41, weak blasting or mechanical excavation of six core soils and the corresponding lower inverts and initial support, 30m behind the fifth section, weak blasting or mechanical excavation of six core soils and the corresponding lower inverts and initial support; S42, reserve six 15% ramps.

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