A roadbed widening structure under steep terrain conditions and its construction method

Abstract

The invention relates to a roadbed widening structure under steep terrain conditions and a construction method thereof; the structure comprises a mountain body, the mountain body comprises an old road and an air-facing steep wall located on the valley side of the old road, the steep wall is excavated inwardly to form a rear excavated side wall and a stepped artificial steep wall; the stepped artificial steep wall is provided with anchoring steel bars and a plurality of anchor rods of different heights, the anchoring steel bars and the anchor rods are anchored inwardly into the mountain body along the stepped artificial steep wall; the invention has the characteristics of safety and stability, small amount of excavation engineering, small volume of docking engineering, low cost, convenient construction and no influence on the passage of the old road, solves the problem that the number of conventional excavation engineering is large or the cost of retaining structure is high and the passage cannot be ensured, reduces the construction difficulty and construction risk, and can provide a certain reference for the design and construction of roadbed widening of mountain highways under steep terrain conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of road widening, and in particular relates to a roadbed widening structure under steep terrain conditions and a construction method thereof. Background Art

[0002] At present, in order to adapt to the rapid growth of transportation volume, the number of roadbed widening and reconstruction projects in mountainous areas is increasing. When widening and reconstructing existing mountainous roads under steep terrain conditions, due to the limitations of the terrain, if the road is widened near the top of the mountain, the amount of excavation will be huge. On the one hand, the road needs to be closed during excavation, and the road cannot be kept open. On the other hand, large-scale excavation of the mountain will put forward higher requirements for slope stability and environmental protection; if the road is widened along the valley bottom, the ordinary retaining structure has the disadvantages of large amount of existing roadbed excavation, large number of retaining and protection projects, high cost, construction difficulties and high risks. At the same time, it will cause great disturbance to the existing road and cannot ensure smooth access. Therefore, it is particularly necessary to find a roadbed widening technical solution that is stable and safe under steep terrain conditions, has low engineering cost, low construction difficulty and construction risk, and meets the requirements of highway access.

[0003] The Chinese patent with publication number CN107419629A proposes a combined widening structure for mountain roads, which mainly adopts an integrally formed L-shaped prefabricated part to widen the road width on the steep side of the mountain road without increasing the construction excavation volume. The construction cost is low and it plays a role in enhancing the traffic capacity of the mountain road. However, the combined widening structure can only widen the existing roadbed by 0.5-2.0 meters, and the roadbed widening width range is too small to meet the needs of some highway reconstruction and expansion projects with a roadbed widening width of more than 2 meters.

[0004] The Chinese patent with publication number CN109989312A proposes a widening structure suitable for cliff roads. It uses anchor rods to pull the excavated mountain closer, making the excavated mountain more stable and meeting the traffic needs of the old road. The concrete load-bearing wall plays a certain supporting role on the roadbed and has better strength. However, since the widening structure uses a large number of anchor rods and concrete, it has obvious disadvantages such as large number of projects and high cost, and it is difficult to meet the needs of some mountain road reconstruction and expansion projects with small investment and tight funds.

[0005] The Chinese patent with publication number CN109989313A proposes a lightweight composite component suitable for widening cliff roads. It uses the technical process of excavating and anchoring to provide a reliable construction platform for widening old roads, and effectively solves the technical difficulties of widening cliff roads by utilizing the characteristics of foam concrete such as high strength, self-compacting, small settlement, and fast construction speed. Due to the large bottom width requirement of foam concrete, it is bound to cause a large number of foam concrete projects and high cost, and foam concrete has the disadvantages of easy cracking. In summary, for some mountain highway reconstruction and expansion projects with small investment and tight funds, the application and promotion of this lightweight composite component has certain limitations.

[0006] Taking into account the widening and reconstruction of existing mountain roads under steep terrain conditions, conventional excavation and retaining structures are difficult to meet the engineering needs, or the existing technical work costs are high. Therefore, the present invention proposes a roadbed widening technology and a construction method under steep terrain conditions, which are stable and safe, have low engineering cost, low construction difficulty and construction risk, and meet the requirements of highway maintenance. The technology has important engineering significance and practical value, and can provide a certain reference for the design and construction of roadbed widening of mountain roads under steep terrain conditions.

[0007] In view of the above technical problems, improvements need to be made. Summary of the invention

[0008] The present invention aims to overcome the defects in the above-mentioned prior art and provide a roadbed widening structure and its construction method under steep terrain conditions which are stable and safe, have low engineering cost, low construction difficulty and construction risk, and meet the requirements of highway maintenance.

[0009] In order to achieve the above purpose, the technical solution adopted by the present invention is: a roadbed widening structure under steep terrain conditions, including a mountain body, the mountain body including an old road and an air-facing steep wall located on the valley side of the old road, the steep wall is excavated inwardly to form an excavated side wall behind the wall and a stepped artificial steep wall; the stepped artificial steep wall is provided with anchoring steel bars and multiple anchor rods of different heights, the anchoring steel bars and anchor rods are anchored inward into the mountain body along the stepped artificial steep wall; a concrete step foundation is provided on the outside of the stepped artificial steep wall; a step foundation convex tenon is provided on the top of the step foundation, a retaining wall is arranged on the step foundation convex tenon, the step foundation and the retaining wall are connected to form a whole, and the retaining wall and the excavated side wall behind the wall are filled with filler, which is compacted and spliced ​​with the old road to form a new road.

[0010] Among them, the excavation slope of the side wall behind the wall is determined based on the geological conditions and the principle of not affecting the openness of the old road.

[0011] As a preferred solution of the present invention, the side wall of the excavation behind the wall is provided with an anchor sprayed protective surface containing steel mesh concrete, and the anchor sprayed protective surface containing steel mesh concrete is located between the backfill behind the wall and the side wall of the excavation behind the wall.

[0012] As a preferred solution of the present invention, the surface of the stepped artificial steep wall is provided with an anchor sprayed protective surface containing reinforced concrete, and the anchor sprayed protective surface containing reinforced concrete is located between the step foundation and the stepped artificial steep wall.

[0013] As a preferred solution of the present invention, a step foundation facade is provided on the outer side of the step foundation.

[0014] As a preferred solution of the present invention, the anchor rod passes through the step foundation, and the anchor rod extends to the outer surface of the step foundation and is provided with a nut and a concrete anchor head, and the nut and the concrete anchor head match the anchor rod.

[0015] As a preferred solution of the present invention, a drainage hole is provided at the bottom of the retaining wall, and the drainage hole is located on the step foundation tenon.

[0016] As a preferred solution of the present invention, a drainage net is provided on the back of the retaining wall, and the bottom of the drainage net is against the drainage hole.

[0017] As a preferred solution of the present invention, a guardrail is provided on the top of the retaining wall, and the outer side of the guardrail is in the same vertical plane as the outer side of the retaining wall.

[0018] As a preferred solution of the present invention, the retaining wall is mortar-laid rubble, rubble concrete or concrete.

[0019] A construction method for a roadbed widening structure under steep terrain conditions comprises the following steps:

[0020] Step A: Excavate the steep wall near the valley side of the old road from top to bottom at a certain slope within the height range of the retaining wall to form the side wall behind the wall, and promptly set up the anchor spraying protection surface containing steel mesh concrete;

[0021] Step B: After the anchor spraying of the side wall behind the wall is implemented, continue to dig vertically downward for 1m-1.5m and then drive a row of anchor steel bars;

[0022] Step C: After the anchor reinforcement is installed, continue to dig vertically downward to form a stepped artificial steep wall. Every time you dig 1.5 meters to 2 meters, start to install a row of anchor rods and lay the anchor sprayed surface containing steel mesh concrete in time;

[0023] Step D: Excavate until the base of the step foundation at the foot of the slope is determined by the design elevation;

[0024] Step E: Set up the step foundation facade and step foundation mortise and tenon formwork from bottom to top, and pour concrete in layers to form the step foundation;

[0025] Step F: After the concrete is cured, nuts are tightened on the anchor rods extending to the outer surface of the step foundation, and concrete is used to seal the anchor to form an anchor head;

[0026] Step G: Set up a retaining wall on the top of the step foundation with tenons. Backfill the retaining wall according to the design requirements and compact it, then connect it to the old road to form a new road.

[0027] The beneficial effects of the present invention are as follows: the present invention has a simple structure and an ingenious design; the retaining wall, the step foundation and the anchor rod are combined; the anchor rod closely connects the step foundation with the mountain, thereby improving the overall stability of the step foundation and the mountain; at the same time, the number of step excavation projects is small and does not affect the normal passage of the old road; the convex tenon on the top of the step foundation forms a whole with the retaining wall, thereby improving the anti-slip ability of the retaining wall; the present invention has the characteristics of safety and stability, small amount of excavation projects, small dock volume, low cost, convenient construction and does not affect the passage of the old road, solves the problem of large number of conventional excavation projects or high cost of retaining structures and inability to ensure passage, reduces construction difficulty and construction risk, and can provide a certain reference for the design and construction of roadbed widening of mountain roads under steep terrain conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the present invention;

[0029] Figure 2 It is a schematic diagram of the excavation structure of the side wall and the stepped artificial steep wall;

[0030] Figure 3 This is a schematic diagram of the structure of the steep wall facing the valley side and the old road;

[0031] The accompanying drawings are numerals in the figure: old road 1, steep wall 2, mountain 3, side wall excavated behind the wall 4, stepped artificial steep wall 5, anchor sprayed surface 6, anchor steel bars 7, anchor rods 8, anchor heads 9, step foundation 10, step foundation base 11, step foundation tenon 12, step foundation facade 13, retaining wall 14, drainage hole 15, drainage net 16, guardrail 17, filler 18, new road 19, side wall excavation slope 20. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Example:

[0035] like Figure 1-3 As shown, the present embodiment provides a roadbed widening structure under steep terrain conditions, including a mountain 3, the mountain 3 including an old road 1 and an empty steep wall 2 located on the valley side of the old road 1, the empty steep wall 2 on the valley side is excavated inwardly to form a rear excavation side wall 4 and a stepped artificial steep wall 5; the stepped artificial steep wall 5 is provided with anchoring steel bars 7 and a plurality of anchor rods 8 of different heights, the anchoring steel bars 7 and the anchor rods 8 are anchored inwardly into the mountain 3 along the stepped artificial steep wall 5; a concrete step foundation 10 is provided on the outer side of the stepped artificial steep wall 5; a step foundation tenon 12 is provided on the top of the step foundation and is connected to the retaining wall 14 as a whole; the retaining wall 14 is backfilled with a filler 18 behind the wall and compacted and then spliced ​​with the old road 1 to form a new road 19.

[0036] The present invention has a simple structure and ingenious design. It combines a retaining wall, a step foundation and an anchor rod. The anchor rod closely connects the step foundation with the mountain, thereby improving the overall stability of the step foundation and the mountain. At the same time, the number of step excavation projects is small and does not affect the normal traffic of the old road. The convex tenon on the top of the step foundation forms a whole with the retaining wall, thereby improving the anti-slip ability of the retaining wall. The present invention has the characteristics of safety and stability, small amount of excavation projects, small dock volume, low cost, convenient construction and does not affect the traffic of the old road. It solves the problem that the number of conventional excavation projects is large or the cost of the retaining structure is high and the traffic cannot be guaranteed, reduces the construction difficulty and construction risk, and can provide a certain reference for the design and construction of roadbed widening of mountain roads under steep terrain conditions.

[0037] The actual operation process includes the following steps:

[0038] Vehicles can always pass on the old road 1. The retaining wall 14 of the old road 1 near the valley side of the steep wall 2 is excavated from top to bottom at a certain side wall excavation slope 20 to form a wall, and the side wall 4 is excavated behind the wall. Anchor sprayed protective surface 6 containing steel mesh concrete is promptly set for reinforcement to ensure the stability of the old road 1 during the traffic process and the safety of construction workers; continue to excavate vertically downward for 1 meter to 1.5 meters, and then install a row of anchor steel bars 7 to anchor it to the mountain 3.

[0039] After the anchoring steel bar 7 is installed, the step-shaped artificial steep wall 5 is formed vertically downward, which is convenient for installing anchor rods 8 and constructing step foundation 10. After digging 1.5-2 meters downward, one row of anchor rods 8 is installed until the excavation reaches the position of the step foundation base 11 at the foot of the slope determined by the design elevation. During the excavation, the anchor spraying protective surface 6 containing steel mesh concrete is laid in time. The anchor spraying protective surface 6 is located between the step foundation 10 and the step-shaped artificial steep wall 5. The step-shaped artificial steep wall 5 formed by the excavation is tightly connected with the mountain 3 through the anchor spraying protective surface 6 and anchor rods 8. The concrete step foundation 10 is formed by pouring concrete after setting the template on the facade 13 and the top of the step foundation.

[0040] The anchor rod 8 passes through the concrete step foundation 10 and is locked with a nut matching the anchor rod 8 at the step foundation facade 13 and sealed with concrete to form an anchor head 9.

[0041] The retaining wall 14 is constructed in layers with the tenon 12 at the top of the concrete step foundation 10. A drainage hole 15 is provided at the lower part of the retaining wall 14 near the tenon 12. The drainage hole 15 can discharge the water collected by the drainage net 16 behind the retaining wall 14 to ensure the dryness of the filler 18 behind the wall, thereby further ensuring that the retaining wall 14 has better stability. A guardrail 17 is provided on the top of the retaining wall 14. The guardrail 17 is located on the side of the steep wall 2 facing the valley side, which can protect vehicles traveling on the new road 19.

[0042] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention; therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0043] Although the following terms are used more frequently in this article: old road 1, steep wall 2, mountain 3, side wall excavated behind the wall 4, stepped artificial steep wall 5, anchor spraying protection 6, anchor steel bar 7, anchor rod 8, anchor head 9, step foundation 10, step foundation base 11, step foundation tenon 12, step foundation facade 13, retaining wall 14, drainage hole 15, drainage net 16, guardrail 17, filler 18, new road 19, side wall excavation slope 20, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A roadbed widening structure under steep terrain conditions, comprising a mountain (3), the mountain (3) comprising an old road (1) and an open steep wall (2) located on the valley side of the old road, the steep wall (2) being excavated inward to form a rear excavated side wall (4) and a stepped artificial steep wall (5); characterized in that: The step-shaped artificial steep wall (5) is provided with anchoring steel bars (7) and a plurality of anchor rods (8) of different heights, and the anchoring steel bars (7) and the anchor rods (8) are anchored inwardly into the mountain (3) along the step-shaped artificial steep wall (5); a concrete step foundation (10) is provided on the outside of the step-shaped artificial steep wall (5); a step foundation convex tenon (12) is provided on the top of the step foundation (10), and a retaining wall (14) is arranged on the step foundation convex tenon (12); the step foundation (10) and the retaining wall (14) are connected to form a whole, and the retaining wall (14) and the side wall (4) excavated behind the wall are connected. The space between the two sides of the concrete step foundation (10) is filled with a filler (18), which is compacted and spliced ​​with the old road (1) to form a new road (19); the retaining wall (14) is constructed in layers on the top tenon (12) of the concrete step foundation (10); the side wall (4) behind the wall is provided with an anchor sprayed protective surface (6) containing steel mesh concrete, and the anchor sprayed protective surface (6) containing steel mesh concrete is located between the backfill filler (18) behind the wall and the side wall (4) behind the wall; the retaining wall (14) is provided with a drainage hole (15) at the bottom of the wall, and the drainage hole (15) is located on the step foundation tenon (12).

2. The roadbed widening structure under steep terrain conditions according to claim 1, characterized in that: The surface of the stepped artificial steep wall (5) is provided with an anchor sprayed protective surface (6) containing reinforced concrete, and the anchor sprayed protective surface (6) containing reinforced concrete is located between the step foundation (10) and the stepped artificial steep wall (5).

3. The roadbed widening structure under steep terrain conditions according to claim 2, characterized in that: A step foundation outer facade (13) is provided on the outer side of the step foundation (10).

4. The roadbed widening structure under steep terrain conditions according to claim 1, characterized in that: The anchor rod (8) passes through the step foundation (10), and the anchor rod (8) extends to the outer surface (13) of the step foundation and is provided with a nut and a concrete anchor head (9), and the nut and the concrete anchor head (9) match the anchor rod (8).

5. The roadbed widening structure under steep terrain conditions according to claim 1, characterized in that: The retaining wall (14) is provided with a drainage net (16) on the back thereof, and the bottom of the drainage net (16) abuts against the drainage hole (15).

6. The roadbed widening structure under steep terrain conditions according to claim 5, characterized in that: A guardrail (17) is provided on the top of the retaining wall (14), and the outer side of the guardrail (17) is in the same vertical plane as the outer side of the retaining wall (14).

7. The roadbed widening structure under steep terrain conditions according to claim 6, characterized in that: The retaining wall (14) is made of mortar-laid rubble, rubble concrete or concrete.

8. A method for constructing a roadbed widening structure under steep terrain conditions as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: Step A: the old road (1) is close to the steep wall (2) on the side of the valley, and the retaining wall (14) is excavated from top to bottom at a certain slope (20) to form a rear excavation side wall (4), and anchor spraying protection (6) containing steel mesh concrete is promptly set; Step B: After the anchor spraying protection (6) of the side wall (4) behind the wall is implemented, continue to vertically excavate 1 meter to 1.5 meters downward, and then install a row of anchor steel bars (7); Step C: After the anchoring steel bars (7) are installed, continue to dig vertically downward to form a stepped artificial steep wall (5). After digging 1.5 to 2 meters downward, start to install a row of anchor rods (8) and promptly lay the anchor sprayed protective surface (6) containing steel mesh concrete. Step D: excavate until the position of the step foundation base (11) at the foot of the slope determined by the design elevation; Step E: Setting up the step foundation facade (13) and the step foundation tenon (12) formwork from bottom to top, and pouring concrete in layers to form the step foundation (10); Step F: After the concrete is cured, the anchor rod (8) extending to the outer surface of the step foundation (13) is tightened with a nut, and the anchor is sealed with concrete to form an anchor head (9); Step G: A retaining wall (14) is set on the top of the step foundation (10) provided with the tenon (12), and a filler (18) is backfilled behind the retaining wall (14) according to the design requirements and compacted to form a new road (19) connected to the old road (1).

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