A tunnel high steep slope dangerous rock fall protection structure and construction method

Abstract

The present invention relates to the field of geotechnical engineering, and specifically to a protective structure and construction method for dangerous rockfall on a high and steep slope of a tunnel, the protective structure comprising a plurality of support columns, a blocking force net and a guide net; the support columns are arranged on the slope above the tunnel opening, and are used to fix the blocking force net and the guide net; the two sides of the blocking force net are fixed on the support columns, and the blocking force net is inclined relative to the horizontal to guide the falling rocks to slide to the outside of the tunnel opening; the bottom side of the blocking force net is connected to the slope; the guide net covers the top side of the blocking force net, and is fixedly connected to the top of the support column and the blocking force net to close the direction of one end of the tunnel opening. The present invention divides the slope surface into a plurality of block-shaped protective sections on the steep slope through the support columns, the blocking force net and the guide net; after the dangerous rock falls in each block, it only acts on the protective structure in the block, and the impact of the dangerous rock falls on the support column and the blocking force net is differentiated, and the protective effect is good, safe and reliable.

Description

Technical Field

[0001] The invention relates to geotechnical engineering, in particular to a tunnel high-steep slope dangerous rock falling protection structure and a construction method. Background Art

[0002] There are many steep slopes on mountain roads, and dangerous rocks and rocks will inevitably fall into the tunnel entrance, which has a great impact on the safety of road operations. For steep slopes, dangerous rocks and rocks have great destructive power. After the outer layer of dangerous rocks and rocks fall, they will continue to develop inward to form new dangerous rocks and rocks. It is very difficult to protect against dangerous rocks and rocks, and it is difficult to clean them up later. When protecting against dangerous rocks and rocks, the method of reinforcing the steep slopes is often adopted. The reinforcement range is large, the engineering volume is high, the difficulty is high, the investment cost is high, and it is not conducive to promotion. Summary of the invention

[0003] The purpose of the present invention is to provide a tunnel high and steep slope dangerous rock falling protection structure and construction method for the problem that the existing technology is difficult to construct and is not conducive to promotion. The structure can effectively protect against dangerous rock falling, is simple to construct, economical and environmentally friendly, and is conducive to promotion and application.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A structure for preventing dangerous rocks from falling on a steep tunnel slope comprises a retaining force-bearing net, a guide net and a plurality of support columns; the support columns are arranged on the slope above the tunnel opening and are used to fix the retaining force-bearing net and the guide net; the retaining force-bearing net is fixed on the support columns at both sides, and the retaining force-bearing net is inclined relative to the horizontal to guide the falling rocks to slide to the outside of the tunnel opening; the bottom side of the retaining force-bearing net is connected to the slope; the guide net covers the top side of the retaining force-bearing net and is fixedly connected to the support columns and the top end of the retaining force-bearing net to close the direction of one end where the tunnel opening is located.

[0006] In the present invention, the support column is used to fix the blocking force net and the guide net, and plays a bearing role on the falling rocks; the falling rocks will quickly and automatically move away from the tunnel entrance on the inclined blocking force net, and the guide net can guide the falling rocks in the three-dimensional space formed by the support column, the blocking force net and the guide net, and will not bounce out to affect the tunnel operation. Therefore, the present invention can effectively protect against dangerous rock falls. In addition, the protective structure is a lightweight structure with low engineering investment, simple implementation, and controllable quality, which is conducive to promotion.

[0007] Preferably, the present invention further comprises fixed anchor rods, which are arranged on the tunnel slope and are used to fix the bottom side of the retaining force-bearing net, so as to prevent the falling rocks from being squeezed out from between the retaining force-bearing net and the slope.

[0008] Preferably, the downward angle θ between the retaining force-bearing net and the vertical direction is less than or equal to 45 degrees, which can accelerate the speed of falling rocks, reduce the impact time of dangerous rocks and rocks staying on the retaining force-bearing net, and extend the service life of the protective structure.

[0009] Preferably, the support columns are arranged in three rows, and the support columns in adjacent rows are staggered at intervals; a support column in the middle row is connected to the support column located diagonally below it by a retaining force-bearing net, which can allow dangerous rocks to slide down along both sides of the protective structure, thereby helping to share the pressure of dangerous rocks on the support columns and the retaining force-bearing net at one time, avoiding the accumulation and later cleaning of dangerous rocks.

[0010] Furthermore, when arranging the protective structure, specifically, the support columns in the middle row are aligned with the center line of the tunnel entrance, and the support columns on both sides are symmetrically arranged at a distance greater than or equal to 2m from the outside of the tunnel entrance, which can better protect against falling dangerous rocks to avoid affecting the operation of the protected tunnel road.

[0011] Preferably, a blocking force-bearing net is also provided between each supporting column in the middle row, so as to divide the protective structure into more block-shaped protective intervals. A layer of protective structure is divided into two protective intervals by a blocking force-bearing net or a guide net, so that the dangerous rockfall in this layer is controlled within a smaller protective interval, reducing the impact.

[0012] Further optionally, the guide net can be a split structure or an integral structure, and the installation method can be selected according to the installation situation. In particular, when the present invention is used to protect a large slope, considering the installation difficulty of the guide net, the guide net can adopt a split structure to achieve rapid installation.

[0013] Preferably, the support column is a reinforced concrete structure or a concrete casting structure outside a porous grouting anchor rod, which has a reliable structure and is easy to construct.

[0014] Based on the above-mentioned tunnel high steep slope dangerous rock and rockfall protection structure, the present invention further provides a construction method thereof, comprising the following steps:

[0015] S1. Locate and cast support columns in the stable area of ​​the steep slope;

[0016] S2. Install a blocking force net between the support columns;

[0017] S3. Construct fixed anchor rods on the slope to fix the retaining force net;

[0018] S4. Install the guide net.

[0019] Among them, step S3 can be optionally adjusted to before step S2.

[0020] This construction method ensures the effective realization of the protective structure function of dangerous rocks and rockfalls on the steep slopes of the above-mentioned tunnels, and is simple to implement and has low investment costs.

[0021] The present invention divides the slope surface into multiple protection zones of block structures through support columns and retaining force nets on high and steep slopes. After falling, dangerous rocks in each block only act on the protection structure in the block, and the potential energy of falling rocks in small-height blocks is reduced, so the impact force of dangerous rocks on support columns and retaining force nets is limited. The present invention proposes a suitable protection structure and construction method for dangerous rocks and rocks on high and steep slopes of tunnels, which is of great significance and has the characteristics of good protection effect of dangerous rocks and rocks, simple construction, economy, environmental protection, and conducive to promotion and application.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The present invention divides the slope surface into multiple block-shaped protection zones on the steep slope through support columns, blocking force nets and guide nets; after the dangerous rocks in each block fall, they only act on the protection structure in the block, thus differentiating the impact of the dangerous rocks on the support columns and blocking force nets. The protection effect is good and safe and reliable.

[0024] 2. The present invention guides dangerous rock falls to a safe area by blocking the force-bearing net and the guide net, which not only ensures the operational safety of the road but also facilitates the later cleaning.

[0025] 3. The present invention does not need to be implemented in the entire range of high and steep slopes, but only needs to focus on protecting key operating areas. The project volume is small, and it is also suitable for emergency protection construction and is flexible in construction.

[0026] 4. The present invention adopts a light structure, which is economical, environmentally friendly and has low investment cost.

[0027] 5. The invention has a simple structure, is easy to implement, has controllable quality, and is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a front schematic diagram of a protective structure for dangerous rockfall on a high and steep slope of a tunnel.

[0029] Figure 2 yes Figure 1 Schematic diagram of the AA structure.

[0030] Figure 3 It is a front schematic diagram of another type of protection structure for dangerous rockfall on high and steep slopes of tunnels.

[0031] Figure 4 yes Figure 3 Schematic diagram of the local structure in the middle II direction.

[0032] Figure 5 yes Figure 3 Schematic diagram of the II-II structure.

[0033] Icon: 1-support column; 2-blocking force net; 3-guide net; 4-fixed anchor rod. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Example 1

[0037] This embodiment provides a tunnel high steep slope dangerous rock fall protection structure, such as Figure 1-2 As shown, it includes a blocking force net 2, a guide net 3 and a plurality of support columns 1; the support column 1 is arranged on the slope above the tunnel entrance, and is used to fix the blocking force net 2 and the guide net 3; the two sides of the blocking force net 2 are fixed on the support columns 1, and the blocking force net 2 is inclined relative to the horizontal to guide the falling rocks to slide to the outside of the tunnel entrance; the bottom side of the blocking force net 2 is connected to the slope; the guide net 3 covers the top side of the blocking force net 2, and is fixedly connected to the top of the support column 1 and the blocking force net 2 to close the direction of one end where the tunnel entrance is located.

[0038] The protective structure can guide the dangerous rockfall to only one side of the tunnel entrance. Figure 1 , 2 As shown, a row of support columns 1 are respectively provided on both sides of the tunnel entrance, and the support columns 1 stand vertically on the slope surface, and the support columns 1 on both sides are staggered. The retaining force net 2 is fixedly connected to the support columns 1 on both sides and is arranged at an angle; the downward angle θ formed by the retaining force net 2 and the vertical direction is less than or equal to 45 degrees. The retaining force net 2 is close to the bottom of the slope body and is fixedly connected to the slope body by fixing anchor rods 4 to prevent falling rocks from squeezing out from between the retaining force net 2 and the slope. A guide net 3 is provided at the top of the retaining force net 2 away from the slope body; the guide net 3 covers the entire outer surface of the protective structure as a whole, and is fixedly connected to the top sides of the support columns 1 and the retaining force net 2, respectively.

[0039] Example 2

[0040] This embodiment also provides a tunnel high steep slope dangerous rock fall protection structure, such as Figure 3-5As shown, it includes a blocking force net 2, a guide net 3 and a plurality of support columns 1; the support column 1 is arranged on the slope above the tunnel entrance, and is used to fix the blocking force net 2 and the guide net 3; the two sides of the blocking force net 2 are fixed on the support columns 1, and the blocking force net 2 is inclined relative to the horizontal to guide the falling rocks to slide to the outside of the tunnel entrance; the bottom side of the blocking force net 2 is connected to the slope; the guide net 3 covers the top side of the blocking force net 2, and is fixedly connected to the top of the support column 1 and the blocking force net 2 to close the direction of one end where the tunnel entrance is located.

[0041] Specifically, Figure 3 , support columns 1 are arranged in three rows, standing vertically on the slope surface. The support column 1 in the middle row is aligned with the center of the tunnel entrance; then the support columns 1 are symmetrically arranged on both sides of the tunnel entrance, and the support columns 1 on both sides are staggered with the support columns 1 in the middle row. Among them, the support columns 1 can be reinforced concrete structures or concrete casting structures outside porous grouting anchor rods, generally with a diameter greater than or equal to 50cm, with reliable structure and convenient construction. The height of the support column 1 exposed outside the slope body is generally 1.0-1.5m, and the support columns 1 on both sides are greater than or equal to 2m from the outside of the tunnel entrance, which can better protect against falling dangerous rocks, so as not to affect the operation of the protected tunnel road.

[0042] like Figure 3-5 The blocking force net 2 is arranged between the support column 1 in the middle row and the adjacent support columns 1 on both sides obliquely below, and is fixedly connected to the support columns 1, so that the dangerous rocks and rocks slide down along the blocking force net 2 to both sides; the oblique downward angle θ formed by the blocking force net 2 and the vertical direction is generally less than or equal to 45 degrees, reducing the impact damage of the dangerous rocks and rocks on the protective structure. The blocking force net 2 can be formed by weaving stress-bearing steel strands. The aperture of the bottom layer of the blocking force net 2 is generally less than or equal to 10 cm, and the upper aperture is less than or equal to 30 cm. In addition, a blocking force net 2 is also arranged between the support columns 1 and 1 in the middle row at the tunnel entrance, dividing the same layer of protection area into two small protection areas, separating the dangerous rocks and rocks in different protection areas, and reducing the impact. Furthermore, fixed anchor rods 4 are arranged at intervals on the slope corresponding to the bottom of the retaining force-bearing net 2, and the fixed anchor rods 4 are tied and fixed to the bottom of the retaining force-bearing net 2 to prevent falling rocks from squeezing out from between the retaining force-bearing net 2 and the slope.

[0043] like Figure 3-5 The guide net 3 is arranged at the top of the support column 1 and the blocking force net 2, and is fixedly connected to the support column 1 and the blocking force net 2 respectively; the guide net 3 can be a flexible curtain-type net. When installing the guide net 3, it can be installed in blocks from top to bottom, which reduces the difficulty of installation and realizes quick installation.

[0044] Example 3

[0045] Based on the tunnel high steep slope dangerous rock and rockfall protection structure described in Example 1 or Example 2, this embodiment provides a construction method thereof, comprising the following steps:

[0046] S1. In the high and steep slope stable area, locate the construction position of the support column 1, then excavate the foundation pit of the support column 1 or construct grouting anchor rods to form the support column 1 structure; the support column 1 is reserved with a connecting steel ring;

[0047] S2. Install the blocking force net 2 between the support columns 1, and the blocking force net 2 is tied and fixed with the connecting steel ring on the support column 1;

[0048] S3. Construction of fixed anchor rods 4 on the slope body to fix the blocking force net 2;

[0049] S4. The guide net 3 is installed in blocks or as a whole from top to bottom. The guide net 3 is fixedly connected to the top of the support column 1 and the blocking force-bearing net 2, and the connection is tied and sutured with steel wire ropes.

[0050] Among them, step S3 can be optionally adjusted to before step S2.

[0051] The present invention divides the slope surface into multiple protection zones of block structures on the steep slope through support columns 1 and blocking force-bearing nets 2. After the dangerous rocks and rocks in each block fall, they only act on the protection structure in the block, and the potential energy of the rocks in the small height blocks is reduced, so the impact force of the dangerous rocks and rocks on the support columns 1 and the blocking force-bearing net 2 is limited. The support column 1 is used to fix the blocking force-bearing net 2 and the guide net 3, and plays a bearing role on the rocks; the rocks and rocks will move quickly and automatically away from the tunnel entrance on the inclined blocking force-bearing net 2, and the guide net 3 can guide the rocks and rocks into the three-dimensional space formed by the support columns 1, the blocking force-bearing net 2 and the guide net 3, and will not bounce out to affect the tunnel operation, so the present invention can effectively protect against the falling of dangerous rocks and rocks. In addition, the protection structures are all lightweight structures, with low engineering investment, simple implementation, and controllable quality, which is conducive to promotion.

[0052] In addition, it should be noted that the "outside" and "both sides" in the text refer to the direction away from the tunnel entrance or the slope body; the "bottom side" and "bottom" refer to the direction close to the slope body; the "outer surface" refers to the opposite surface of the protection interval structure relative to the direction of the slope body; the "top" and "top side" refer to the direction close to the end of the protected tunnel entrance and away from the slope body. The benchmark selected by the present invention may be different from that selected by the conventional method.

[0053] 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 protection scope of the present invention.

Claims

1. A tunnel high steep slope dangerous rock fall protection structure, characterized in that: The invention comprises a blocking force-bearing net (2), a guide net (3) and a plurality of support columns (1); the support columns (1) are arranged on the side slope of the tunnel entrance and are used to fix the blocking force-bearing net (2) and the guide net (3); the support columns (1) are respectively fixed on opposite sides of the blocking force-bearing net (2); the blocking force-bearing net (2) is inclined relative to the horizontal so as to guide the falling rocks to slide toward the outside of the tunnel entrance; the oblique downward angle θ between the blocking force-bearing net (2) and the vertical direction is less than or equal to 45 degrees; the bottom side of the blocking force-bearing net (2) close to the side slope is fixedly connected to the side slope through a fixed anchor rod (4); the guide net (3) covers the top side of the blocking force-bearing net (2) away from the side slope and is fixedly connected to the support columns (1) and the top ends of the blocking force-bearing net (2).

2. The dangerous rockfall protection structure according to claim 1 is characterized in that: The support columns (1) are arranged in three rows, and the support columns (1) in adjacent rows are arranged in an interlaced manner; a support column (1) in the middle row is connected to a support column (1) located obliquely below it via the blocking force-bearing net (2).

3. The dangerous rockfall protection structure according to claim 2 is characterized in that: The support columns (1) located in the middle row are aligned with the center line of the tunnel opening, and the support columns (1) on both sides are symmetrically arranged at a distance greater than or equal to 2 m from the outside of the tunnel opening.

4. The dangerous rockfall protection structure according to claim 2 is characterized in that: The blocking force-bearing net (2) is also provided between the support columns (1) located in the middle row.

5. The dangerous rockfall protection structure according to claim 2 is characterized in that: The guide net (3) is a split structure or an integral structure.

6. The dangerous rockfall protection structure according to any one of claims 1 to 5, characterized in that: The support column (1) is a reinforced concrete structure or a structure of concrete cast outside a porous grouting anchor rod.

7. A method for constructing a protective structure for dangerous rockfall on a steep slope of a tunnel, characterized in that: The dangerous rockfall protection structure according to any one of claims 1 to 6 comprises the following steps: S1. Locate and cast support columns (1) in the stable area of ​​the steep slope; S2. Installing a blocking force net (2) between the support columns (1); S3. constructing a fixed anchor rod (4) on the slope body to fix the retaining force net (2); S4. Installing the guide net (3).

8. The construction method according to claim 7, characterized in that: Step S3 is adjusted to before step S2.

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