阅读说明：本技术 一种隧道洞门结构及其施工方法 (Tunnel portal structure and construction method thereof ) 是由 马栋 钱师雄 胡志位 李伟 沈跃辉 刘石长 王凤喜 施有志 姚加焕 王泽坤 金仁 于 2021-07-12 设计创作，主要内容包括：本发明涉及轨道交通技术领域,具体而言,涉及一种隧道洞门结构及其施工方法。所述衬砌结构、隧道洞门结构、洞门挡墙和洞门边坡防护结构,所述衬砌结构设置在隧道内,所述衬砌结构包括有隧道明洞衬砌和隧道暗洞衬砌；所述隧道洞门结构与所述隧道相连,所述隧道洞门结构通过双层锚筋和隧道明洞衬砌固定连接；所述洞门挡墙设置在所述隧道洞门结构靠近河谷的一侧；所述洞门边坡防护结构设置在所述隧道洞门结构上方。本发明通过设置排水结构来保障隧道内部和隧道外部的水能够排出,并且在隧道外侧设置洞门挡墙来增加隧道洞门结构的稳定性。隧道边坡设置锚杆和防护层防止水土流失,并且在保证稳定性的同时也保护了地理环境。(The invention relates to the technical field of rail transit, in particular to a tunnel portal structure and a construction method thereof. The lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining and a tunnel hidden tunnel lining; the tunnel portal structure is connected with the tunnel, and the tunnel portal structure is fixedly connected with a tunnel open cut tunnel lining through double-layer anchor bars; the tunnel portal retaining wall is arranged on one side, close to the river valley, of the tunnel portal structure; the tunnel portal slope protection structure is arranged above the tunnel portal structure. The invention ensures that water inside and outside the tunnel can be discharged by arranging the drainage structure, and the stability of the tunnel portal structure is improved by arranging the portal retaining wall on the outer side of the tunnel. The tunnel slope sets up stock and inoxidizing coating and prevents soil erosion and water loss to geographical environment has also been protected when guaranteeing stability.)

1. A tunnel portal structure, comprising:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining (1) and a tunnel hidden tunnel lining (2);

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining (1) through a double-layer anchor bar (4);

the tunnel portal structure comprises a portal retaining wall (3), and the portal retaining wall (3) is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

2. The tunnel portal structure of claim 1, wherein: the tunnel portal side slope protection structure further comprises a backfill soil layer, the backfill soil layer is arranged above the tunnel portal structure, a gravel layer is arranged at the bottom of the backfill soil layer, a thick cultivation soil layer is arranged above the gravel layer, and a thick clay water-resisting layer is arranged between the thick cultivation soil layer and the gravel layer.

3. The tunnel portal structure of claim 1, wherein: and a settlement joint (13) with the width of 2CM is arranged between the tunnel open cut tunnel lining (1) and the tunnel blind hole lining (2), and the settlement joint (13) is arranged perpendicular to the ground.

4. The tunnel portal structure of claim 1, wherein: the double-layer anchor bars (4) are two HRB400 steel bars arranged in parallel, and the end parts of the double-layer anchor bars (4) are fixedly connected with the main bars of the tunnel open cut tunnel lining (1).

5. The tunnel portal structure of claim 2, wherein: the top of tunnel portal structure is provided with first drainage ditch (5), first drainage ditch (5) with the backfill soil layer contacts, first drainage ditch (5) with the minimum of backfill soil layer upper surface flushes, portal barricade (3) are provided with second escape canal (6) on being close to the lateral wall of river valley, second escape canal (6) with portal barricade (3) are close to the lateral wall parallel arrangement of river valley, first drainage ditch (5) with second escape canal (6) top links to each other.

6. The tunnel portal structure of claim 1, wherein: the tunnel portal retaining wall is characterized in that a first water permeable pipe (7) is arranged on the inner side of the tunnel portal retaining wall (3), the first water permeable pipe (7) is arranged in parallel with the inner wall of the tunnel portal structure, a pre-buried drain pipe (8) is arranged at the bottom of the tunnel portal structure, and the pre-buried drain pipe (8) is connected with the first water permeable pipe (7) through a multi-way pipe (14).

7. The tunnel portal structure of claim 1, wherein: a second permeable pipe (9), a third permeable pipe (15) and a fourth permeable pipe (18) are embedded in the backfill soil layer of the tunnel portal side slope, the second permeable pipe (9) and the fourth permeable pipe are both arranged transversely, the third permeable pipe (15) is arranged longitudinally, the second permeable pipe (9), the third permeable pipe (15) and the fourth permeable pipe (18) are connected through a multi-way pipe (14), the end of the second permeable pipe (9) connected with the third permeable pipe (15) is lower than the end which is not connected, the end of the fourth permeable pipe (18) connected with the third permeable pipe (15) is lower than the end which is not connected, a plurality of second permeable pipes (9) are arranged, a plurality of second permeable pipes (9) are arranged in parallel, the fourth permeable pipe (18) is provided with a plurality of the fourth permeable pipes (18) which are arranged in parallel.

8. The tunnel portal structure of claim 1, wherein: tunnel portal structure top is provided with tunnel entrance to a cave uphill (16), tunnel entrance to a cave uphill (16) are provided with initiative protection network (10) and passive protection network (11), initiative protection network (10) tiling sets up at tunnel entrance to a cave uphill (16) upper surface, passive protection network (11) set up perpendicularly tunnel entrance to a cave uphill (16) upper surface, the top of initiative protection network (10) with the end fixing of passive protection network (11) links to each other.

9. A construction method of a tunnel portal structure is characterized by comprising the following steps:

excavating a tunnel opening foundation pit from a tunnel side slope by adopting a slope-releasing method, excavating side ditches at two sides of the tunnel, and treating the tunnel side slope by adopting a net-jet support method;

a first water permeable pipe (7) is arranged on the outer side of the tunnel, a pre-buried drain pipe (8) is arranged at the bottom of the tunnel portal structure, and the first water permeable pipe (7) and the pre-buried drain pipe (8) are connected through a multi-way pipe (14);

pouring a tunnel portal structure by using concrete, arranging a portal retaining wall (3) at one side of the tunnel portal structure close to a valley, connecting the portal retaining wall (3) with a tunnel open cut tunnel lining (1) by using a double-layer anchor bar (4), and arranging a second drainage ditch (6) on the portal retaining wall (3);

pre-burying a second water permeable pipe (9) at the outer side of the construction tunnel portal, and connecting the second water permeable pipe (9) with side ditches at two sides of the tunnel;

a first drainage ditch (5) is poured at the top of the tunnel portal structure, and then an active protective net (10) and a passive protective net (11) are arranged on an uphill slope of the tunnel portal;

and after the concrete of the tunnel portal structure is solidified, backfilling a gravel layer on an upward slope of the tunnel portal, constructing a thick clay water-resisting layer, and paving a thick root planting soil layer for greening.

10. The tunnel portal structure of claim 9, wherein: reinforcing bar net is laid to tunnel entrance to a cave side slope excavation face, just lay stock (12) between the reinforcing bar net, will the top of stock (12) with the reinforcing bar net is fixed continuous.

Technical Field

The invention relates to the technical field of tunnel construction, in particular to a tunnel portal structure and a construction method thereof.

Background

The tunnel construction is developed along with more and more tunnels in China, but the tunnel construction is always accompanied by dangers, the tunnel door construction is the most important point, and the drainage and the stability of the tunnel door are the major key points of the tunnel construction, so that a construction method with both drainage and safety and stability is needed.

Disclosure of Invention

The present invention aims to provide a tunnel portal structure and a construction method thereof to improve the above problems. In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

in one aspect, an embodiment of the present application provides a tunnel portal structure, including:

the tunnel lining structure comprises a tunnel open cut tunnel lining and a tunnel closed cut tunnel lining; the tunnel portal structure is connected with the tunnel, and the tunnel portal structure is fixedly connected with a tunnel open cut tunnel lining through double-layer anchor bars; the tunnel portal retaining wall is arranged on one side, close to the river valley, of the tunnel portal structure; the tunnel portal slope protection structure is arranged above the tunnel portal structure.

Optionally, the portal side slope protection structure further comprises a backfill soil layer, the backfill soil layer is arranged above the tunnel portal structure, a gravel layer is arranged at the bottom of the backfill soil layer, a thick cultivation soil layer is arranged above the gravel layer, and a thick clay water-resisting layer is arranged between the thick cultivation soil layer and the gravel layer.

Optionally, a settlement joint with the width of 2CM is arranged between the tunnel open cut tunnel lining and the tunnel blind cut tunnel lining, and the settlement joint is arranged perpendicular to the ground.

Optionally, the double-layer anchor bars are two HRB400 steel bars arranged in parallel, and the end portions of the double-layer anchor bars are fixedly connected with the main bars of the tunnel open cut tunnel lining.

Optionally, the top of tunnel portal structure is provided with first drainage ditch, first drainage ditch with the backfill soil layer contacts, first drainage ditch with the minimum of backfill soil layer upper surface flushes, be provided with the second escape canal on the lateral wall that the portal barricade is close to the river valley, the second escape canal with the lateral wall parallel arrangement that the portal barricade is close to the river valley, first drainage ditch with second escape canal top links to each other.

Optionally, portal retaining wall inboard is provided with the first pipe of permeating water, first permeate water manage with tunnel portal structure inner wall parallel arrangement, tunnel portal structure bottom is provided with pre-buried drain pipe, pre-buried drain pipe with the first pipe of permeating water is connected through the multi-way pipe.

Optionally, pre-buried in the backfill soil layer of portal side slope has the second to permeate water pipe, the third to permeate water pipe and the fourth pipe of permeating water, the second permeate water the pipe with the fourth is permeated water the equal horizontal setting of pipe, the third is permeated water the vertical setting of pipe, the second is permeated water pipe, the third is permeated water pipe and the fourth is permeated water the pipe and is connected through many-way pipe, the second permeate water the pipe with the third is permeated water the one end that the pipe links to each other and is less than not continuous one end, the fourth permeate water the pipe with the one end that the pipe links to each other is less than not continuous one end to the third, the second is permeated water the pipe and is provided with many, many the second is permeated water pipe parallel arrangement, the fourth is permeated water the pipe and is provided with many, many the fourth is permeated water pipe parallel arrangement.

Optionally, tunnel portal structure top is provided with tunnel entrance upward slope, tunnel entrance upward slope is provided with initiative protection network and passive protection network, the tiling of initiative protection network sets up at tunnel entrance upward slope upper surface, passive protection network sets up perpendicularly tunnel entrance upward slope upper surface, the top of initiative protection network with the tip of passive protection network is fixed links to each other.

On the other hand, the embodiment of the application provides a tunnel portal structure construction method, which comprises the following steps:

excavating a tunnel opening foundation pit from a tunnel side slope by adopting a slope-releasing method, excavating side ditches at two sides of the tunnel, and treating the tunnel side slope by adopting a net-jet support method;

a first water permeable pipe is arranged on the outer side of the tunnel, a pre-buried drain pipe is arranged at the bottom of the tunnel portal structure, and the first water permeable pipe and the pre-buried drain pipe are connected through a multi-way pipe;

pouring a tunnel portal structure by using concrete, arranging a portal retaining wall on one side of the tunnel portal structure close to a valley, connecting the portal retaining wall with a tunnel open cut tunnel lining by using double-layer anchor bars, and arranging a second drainage ditch on the portal retaining wall;

pre-burying a second water permeable pipe outside the construction tunnel portal, and connecting the second water permeable pipe with side ditches on two sides of the tunnel;

a first drainage ditch is poured at the top of the tunnel portal structure, and then an active protective net and a passive protective net are arranged on an upward slope of the tunnel portal;

and after the concrete of the tunnel portal structure is solidified, backfilling a gravel layer on an upward slope of the tunnel portal, constructing a thick clay water-resisting layer, and paving a thick root planting soil layer for greening.

Optionally, the reinforcing bar net is laid to tunnel entrance to a cave side slope excavation face, and lay the stock between the reinforcing bar net, will the top of stock with the reinforcing bar net is fixed continuous.

The invention has the beneficial effects that:

the invention ensures that water inside and outside the tunnel can be discharged by arranging the drainage structure, and the stability of the tunnel portal structure is improved by arranging the portal retaining wall outside the tunnel. The tunnel slope sets up stock and inoxidizing coating and prevents that soil erosion and water loss has also protected geographical environment when guaranteeing stability, has still set up the subsiding crack moreover between tunnel open cut and dark hole, prevents that the inhomogeneous settlement of tunnel entrance to a cave from leading to the stability reduction in tunnel.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic cross-sectional view of a tunnel portal according to an embodiment of the present invention;

FIG. 2 is a schematic view of a tunnel portal structure drainage structure according to an embodiment of the present invention;

fig. 3 is a schematic sectional view at a-a in fig. 2.

The labels in the figure are: 1. lining the open cut tunnel; 2. lining a tunnel blind hole; 3. a tunnel portal retaining wall; 4. double-layer anchor bars; 5. a first drain ditch; 6. a second drain ditch; 7. a first water permeable pipe; 8. pre-burying a drain pipe; 9. a second water permeable pipe; 10. an active protective net; 11. a passive protective net; 12. an anchor rod; 13. settling seams; 14. a multi-pass tube; 15. a third water permeable pipe; 16. a tunnel entrance uphill slope; 17. a third drainage ditch; 18. and a fourth permeable pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

Example 1

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The invention ensures that water inside and outside the tunnel can be discharged by arranging the drainage structure, and the stability of the tunnel portal structure is improved by arranging the portal retaining wall outside the tunnel. The tunnel slope sets up stock and inoxidizing coating and prevents that soil erosion and water loss has also protected geographical environment when guaranteeing stability, has still set up the subsiding crack moreover between tunnel open cut and dark hole, prevents that the inhomogeneous settlement of tunnel entrance to a cave from leading to the stability reduction in tunnel.

Example 2

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The tunnel portal side slope protection structure further comprises a backfill soil layer, the backfill soil layer is arranged above the tunnel portal structure, a gravel layer is arranged at the bottom of the backfill soil layer, a thick cultivation soil layer is arranged above the gravel layer, and a thick clay water-resisting layer is arranged between the thick cultivation soil layer and the gravel layer.

The backfill soil layer is arranged, so that the stability of the tunnel portal is improved, the water and soil loss is prevented, and the ground surface is greened to improve the attractiveness.

Example 3

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

And a settlement joint 13 with the width of 2CM is arranged between the open tunnel lining 1 and the blind tunnel lining 2, and the settlement joint 13 is arranged perpendicular to the ground.

According to the invention, the settlement joint is arranged between the open cut tunnel and the blind hole of the tunnel, so that the stability of the tunnel is prevented from being reduced due to uneven settlement of the tunnel portal, the influence of settlement on the tunnel portal is reduced, and the safety of constructors is ensured.

Example 4

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The double-layer anchor bars 4 are two HRB400 steel bars arranged in parallel, and the end parts of the double-layer anchor bars 4 are fixedly connected with the main bars of the tunnel open cut tunnel lining 1.

According to the invention, the stability of the tunnel door structure is increased by fixing the tunnel open cut tunnel lining through the double-layer anchor bolts, and meanwhile, the main reinforcement of the tunnel open cut tunnel lining is fixedly connected with the double-layer anchor bolts, so that the tunnel open cut tunnel lining is prevented from falling off.

Example 5

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The top of tunnel portal structure is provided with first drainage ditch 5, first drainage ditch 5 with the backfill soil layer contacts, first drainage ditch 5 with the minimum of backfill soil layer upper surface flushes, portal barricade 3 is provided with second escape canal 6 on being close to the lateral wall of river valley, second escape canal 6 with portal barricade 3 is close to the lateral wall parallel arrangement of river valley, first drainage ditch 5 with 6 tops in second escape canal link to each other.

According to the invention, the drainage ditch is arranged above the hole door and on the side wall of the retaining wall to drain accumulated water above the hole door side slope, so that the hole door side slope is prevented from sliding, and meanwhile, the hole door is prevented from collapsing due to the accumulated water above the hole door, and the construction danger is reduced.

Example 6

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The 3 inboard of portal barricade are provided with first pipe 7 of permeating water, first pipe 7 of permeating water with tunnel portal structure inner wall parallel arrangement, tunnel portal structure bottom is provided with pre-buried drain pipe 8, pre-buried drain pipe 8 with first pipe 7 of permeating water is connected through multi-ported pipe 14.

According to the tunnel portal structure, the first water permeable pipe 7 is arranged on the inner wall of the tunnel portal structure, so that underground water in the tunnel is discharged into the side ditch, the possibility of water accumulation at the portal is reduced, and the stability of the portal structure is improved.

Example 7

As shown in fig. 1, the present embodiment provides a tunnel portal structure, which is characterized by comprising:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

The pre-buried second pipe 9, the third pipe 15 and the fourth pipe 18 of permeating water of having pre-buried in the backfill soil layer of portal side slope, the second permeate water pipe 9 with the fourth is permeated water the equal horizontal setting of pipe, the third is permeated water pipe 15 and is vertically set up, the second is permeated water pipe 9, the third and is permeated water pipe 15 and the fourth and is permeated water pipe 18 and be connected through multi-ported pipe 14, the second permeate water pipe 9 with the third is permeated water pipe 15 and is linked to each other one end and be less than not continuous one end, the fourth permeate water pipe (18) with the third is permeated water pipe 15 and is linked to each other one end and be less than not continuous one end, the second is permeated water pipe 9 and is provided with many, many the second is permeated water pipe 9 parallel arrangement, the fourth is permeated water pipe 18 and is provided with many, many the fourth is permeated water pipe 18 parallel arrangement.

According to the invention, the plurality of second permeable pipes 9, the plurality of third permeable pipes 15 and the plurality of fourth permeable pipes 18 are arranged, and the second permeable pipes 9, the third permeable pipes 15 and the fourth permeable pipes 18 are distributed in a crossed net shape, so that all accumulated water around the backfill soil layer of the portal side slope is gathered and drained into the drainage ditch, the accumulated water of the backfill soil layer is reduced, the backfill soil layer slope is prevented from sliding, and the construction risk is reduced.

Example 7

As shown in fig. 1, the present embodiment provides a tunnel portal structure, including:

the lining structure is arranged in the tunnel and comprises a tunnel open cut tunnel lining 1 and a tunnel blind hole lining 2;

the tunnel portal structure is connected with the tunnel and is fixedly connected with the open cut tunnel lining 1 through the double-layer anchor bars 4;

the tunnel portal retaining wall 3 is arranged on one side, close to a river valley, of the tunnel portal structure; and

the tunnel portal slope protection structure is arranged above the tunnel portal structure.

Tunnel portal structure top is provided with tunnel portal adverse slope 16, tunnel portal adverse slope 16 is provided with initiative protection network 10 and passive protection network 11, initiative protection network 10 tiling sets up at tunnel portal adverse slope 16 upper surface, passive protection network 11 sets up perpendicularly tunnel portal adverse slope 16 upper surface, the top of initiative protection network 10 with passive protection network 11's end portion is fixed links to each other.

According to the invention, the active protective net 10 and the passive protective net 11 are arranged to prevent the influence of side slope rock fall and rockfall on the tunnel portal and reduce the construction risk.

Example 9

As shown in fig. 1, the present embodiment provides a method for constructing a tunnel portal structure, including:

excavating a tunnel opening foundation pit from a tunnel side slope by adopting a slope-releasing method, excavating side ditches at two sides of the tunnel, and treating the tunnel side slope by adopting a net-jet support method;

a first water permeable pipe 7 is arranged on the outer side of the tunnel, an embedded drain pipe 8 is arranged at the bottom of the tunnel portal structure, and the first water permeable pipe 7 and the embedded drain pipe 8 are connected through a multi-way pipe 14;

pouring a tunnel portal structure by using concrete, arranging a portal retaining wall 3 on one side of the tunnel portal structure close to a valley, connecting the portal retaining wall 3 with a tunnel open cut tunnel lining 1 by using double-layer anchor bars 4, and arranging a second drainage ditch 6 on the portal retaining wall 3;

pre-burying a second water permeable pipe 9 at the outer side of the construction tunnel portal, and connecting the second water permeable pipe 9 with side ditches at two sides of the tunnel;

a first drainage ditch 5 is poured at the top of the tunnel portal structure, and then an active protective net 10 and a passive protective net 11 are arranged on an upward slope of the tunnel portal;

and after the concrete of the tunnel portal structure is solidified, backfilling a gravel layer on an upward slope of the tunnel portal, constructing a thick clay water-resisting layer, and paving a thick root planting soil layer for greening.

The side slope is reinforced by a net-jet supporting method, the drainage structure is pre-embedded to discharge drainage in the tunnel portal side slope and the tunnel portal backfill soil layer, and the protective structure is arranged to prevent rock rolls and falling rocks on the mountain from influencing the tunnel portal.

Example 9

As shown in fig. 1, the present embodiment provides a method for constructing a tunnel portal structure, including:

excavating a tunnel opening foundation pit from a tunnel side slope by adopting a slope-releasing method, excavating side ditches at two sides of the tunnel, and treating the tunnel side slope by adopting a net-jet support method;

a first water permeable pipe 7 is arranged on the outer side of the tunnel, an embedded drain pipe 8 is arranged at the bottom of the tunnel portal structure, and the first water permeable pipe 7 and the embedded drain pipe 8 are connected through a multi-way pipe 14;

pouring a tunnel portal structure by using concrete, arranging a portal retaining wall 3 on one side of the tunnel portal structure close to a valley, connecting the portal retaining wall 3 with a tunnel open cut tunnel lining 1 by using double-layer anchor bars 4, and arranging a second drainage ditch 6 on the portal retaining wall 3;

pre-burying a second water permeable pipe 9 at the outer side of the construction tunnel portal, and connecting the second water permeable pipe 9 with side ditches at two sides of the tunnel;

a first drainage ditch 5 is poured at the top of the tunnel portal structure, and then an active protective net 10 and a passive protective net 11 are arranged on an upward slope of the tunnel portal;

and after the concrete of the tunnel portal structure is solidified, backfilling a gravel layer on an upward slope of the tunnel portal, constructing a thick clay water-resisting layer, and paving a thick root planting soil layer for greening.

Reinforcing bar net is laid to tunnel entrance to a cave side slope excavation face, just lay stock 12 between the reinforcing bar net, will the top of stock 12 with the reinforcing bar net is fixed continuous.

According to the invention, the reinforcing mesh is laid on the upper surface of the excavation surface of the hole side slope, and the reinforcing mesh is fixed on the upper surface of the excavation surface of the hole side slope through the anchor rod 12, so that the landslide of the excavation surface of the hole side slope is prevented.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.