A trumpet-shaped slope retaining structure and construction method at the tunnel entrance

Abstract

The present invention discloses a trumpet-shaped slope retaining structure and construction method at the tunnel entrance. The retaining structure includes flange piles, and the flange piles are arranged on the inner side of the slope. The flange piles are distributed at intervals along the trend of the corresponding slope. The flange part of the flange pile is located on the side away from the corresponding slope. An L-shaped retaining plate is connected between two adjacent flange piles on the same side. The two end parts of the retaining plate are respectively connected to the flange parts of the corresponding flange piles. The height of the retaining plate is adapted to the height of the flange pile, and the height of the flange pile is adapted to the height of the slope platform area. This structure can effectively disperse the earth pressure received by the retaining plate to two adjacent flange piles, avoid the dislocation between the retaining plate and the flange pile, eliminate the weak link of the traditional pile-plate structure, ensure the stability of the retaining system, and enable the flange pile near the end wall to be closely attached to the tunnel portal end wall, thereby better protecting the end wall and effectively improving the safety and reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly relates to a retaining structure and construction method for a trumpet-shaped slope at the tunnel entrance. Background Art

[0002] Tunnel entrance types include bias pressure type, single pressure type, ear wall type, double ear wall type, bevel cut type, etc. Generally, when using bias pressure type, single pressure type, ear wall type, or bevel cut type tunnel portals, the distance between the two side slopes at the entrance is small, and the distance between the two side slopes gradually expands after a certain distance outward, that is, a trumpet-shaped slope is generated outside the tunnel.

[0003] At present, for the trumpet-shaped slope section, including single-sided and double-sided trumpet-shaped slopes, inclined plate support is usually adopted. However, when the slope is relatively high and the geological conditions are extremely poor (such as sand, soil, fully weathered strata, etc.), a pile-plate structure is suitable. The traditional pile-plate structure is maturely applied in non-trumpet-shaped slope sections. However, when a pile-plate structure is set in a trumpet-shaped slope section, if the rock and soil layer pressure of the slope is relatively large, the connection between the pile and the plate is likely to be displaced, resulting in the failure of the retaining function and posing a safety hazard. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the existing pile-plate structure of the trumpet-shaped slope section, which is prone to displacement and leads to the failure of the retaining function, and to provide a retaining structure and construction method for a trumpet-shaped slope at the tunnel entrance.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A retaining structure for a trumpet-shaped slope at the tunnel entrance includes flange piles. The flange piles are arranged on the inner side of the slope, and the flange piles are distributed at intervals along the trend of the corresponding slope. The flange part of the flange pile is located on the side away from the corresponding slope. An L-shaped retaining plate is connected between two adjacent flange piles on the same side. The two end parts of the retaining plate are respectively connected to the flange parts of the corresponding flange piles. The top surface position of the retaining plate is adapted to the top surface position of the flange pile, and the height of the flange pile is adapted to the height of the slope platform area.

[0007] Adopt a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention. The slope is a trumpet-shaped slope section. The flange piles are distributed at intervals along the trend of the slope, that is, as the trumpet-shaped trend of the slope, the spacing between the corresponding flange piles on both sides of the slope gradually expands. The adjacent two flange piles on the same side are arranged in a staggered manner, which can reduce the excavation volume or backfill volume, lower the construction cost and difficulty, shorten the construction period. The retaining plate between two adjacent flange piles adopts an L-shaped structure, and the two sections of the L-shaped structure are respectively connected to the corresponding flange parts, so that the retaining plate can be tightly connected to the two flange parts respectively. Compared with the inclined plate between piles, it is not easy to slip, and can more effectively disperse the earth pressure received by the retaining plate to the two adjacent flange piles. The flange piles arranged in a staggered manner and the retaining plate with straight lap between them effectively avoid the dislocation between the retaining plate and the flange piles, eliminate the weak links of the traditional pile-plate structure, ensure the stability of the retaining system, and enable the flange piles near the end wall to be closely attached to the tunnel portal end wall, thereby better protecting the end wall and effectively improving the safety and reliability.

[0008] Preferably, a number of drain holes are provided in the retaining plate.

[0009] Further preferably, a filter layer is provided on the side of the retaining plate close to the corresponding slope, and a drainage net is provided between the retaining plate and the filter layer.

[0010] Effectively avoid soil and stone slag from entering the drain holes.

[0011] Further preferably, the filter layer comprises bagged sand and pebbles.

[0012] Preferably, the top surface of the retaining structure is closed with a concrete layer.

[0013] Preferably, the bottom end of the retaining plate extends into the ground.

[0014] Preferably, the ground between two adjacent flange piles is closed with a concrete layer.

[0015] A construction method for a trumpet-shaped slope retaining structure at the tunnel entrance includes the following steps:

[0016] a. Construct the collar of the flange pile, excavate the pile hole of the flange pile, construct the retaining wall while excavating, and construct the flange pile.

[0017] b. After all the flange piles are constructed, vertically excavate the rock and soil on the side of the flange pile close to the road and the slope between two adjacent flange piles.

[0018] c. Demolish the collar and the retaining wall.

[0019] d. Set up the filter layer and drainage net in layers, and set up the retaining plates in layers. The filter layer and drainage net are arranged on the side of the retaining plate close to the slope to complete the retaining of the slope.

[0020] Using the construction method of a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention, first construct the flange piles, and then excavate the rock and soil of the slope in front of and between the piles, which is beneficial to reducing the construction risk. Then set up the filter layer and drainage net behind the retaining plate, which is beneficial to reducing the construction difficulty of the retaining plate, effectively improving the construction efficiency, beneficial to ensuring the stable connection between the retaining plate and the flange piles, reducing the risk of displacement and dislocation, and improving the stability of the retaining structure.

[0021] The excavation can be carried out by mechanical excavation or blasting excavation.

[0022] Preferably, after breaking the lock mouth and retaining wall, the ground between two adjacent flange piles is sealed with a concrete layer.

[0023] Preferably, after the retaining plate is installed, the top surface of the retaining structure is sealed with a concrete layer.

[0024] Preferably, the height of each layer of the filter layer and drainage net is 0.5 - 1m.

[0025] To sum up, compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. Using a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention, two adjacent flange piles on the same side are arranged in a staggered manner, and two L-shaped sections are respectively connected to the corresponding flange parts and are closely attached to the corresponding flange piles, effectively dispersing the soil pressure received by the retaining plate to two adjacent flange piles. Using the staggered flange piles and the straight lap joint retaining plate between them effectively avoids the dislocation between the retaining plate and the flange piles, eliminates the weak links of the traditional pile-plate structure, ensures the stability of the retaining system, and enables the flange pile close to the end wall to be closely attached to the tunnel portal end wall, thus better protecting the end wall and effectively improving the safety and reliability.

[0027] 2. Using a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention, a filter layer and a drainage net are provided on the side close to the slope, with smooth drainage, effectively preventing water accumulation behind the piles, reducing the water pressure behind the piles, being beneficial to the engineering safety, and improving the stability of the retaining structure.

[0028] 3. Using the construction method of a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention is beneficial to reducing the construction risk and construction difficulty, effectively improving the construction efficiency, beneficial to ensuring the stable connection between the retaining plate and the flange piles, reducing the risk of displacement and dislocation, and improving the stability of the retaining structure.

[0029] 4. Using the construction method of a trumpet-shaped slope retaining structure at the tunnel entrance according to the present invention, the process of pile formation, excavation, and slab installation is more reasonable, which is conducive to rapid construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural layout diagram of a trumpet-shaped slope retaining structure at the tunnel entrance according to the present invention;

[0031] Figure 2 It is a large-scale structural detail drawing of the retaining structure in Embodiment 1;

[0032] Figure 3 is Figure 2 the structural cross-sectional view of A-A in

[0033] Markings in the figure: 1 - flange pile, 2 - slope, 3 - retaining plate, 4 - drain hole, 5 - filter layer, 6 - drainage net, 7 - end wall. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0035] Embodiment 1

[0036] As Figures 1 - 3 shown, for a trumpet-shaped slope retaining structure at the tunnel entrance according to the present invention, in this embodiment, taking the case where both sides are trumpet-shaped slope sections as an example, the retaining structure includes flange piles 1, the flange piles 1 are arranged outside the end wall 7, the flange piles 1 are arranged inside the corresponding slope 2 on each side, and the flange piles 1 are spaced at intervals along the trend of the corresponding slope 2, that is, along the trumpet-shaped trend of the slope 2, the spacing between the corresponding flange piles 1 on both slopes 2 gradually increases, as Figure 1As shown, the flange part of the flange pile 1 is located on the side away from the corresponding slope 2. The width direction of the flange of each flange pile 1 is still parallel to the road surface direction, that is, the flange pile 1 can be closely attached to the end wall 7. The adjacent two flange piles 1 on the same side are arranged in a staggered manner. An L-shaped retaining plate 3 is connected between the adjacent two flange piles 1 on the same side. The retaining plate 3 can be a precast member or a cast-in-place member. The two ends of the retaining plate 3 are respectively connected to the flange parts of the corresponding flange piles 1. The retaining plate 3 includes two mutually perpendicular sections. One section is arranged along the side wall of the flange pile 1 and connected to the corresponding flange part, and the other section is connected to the side wall and flange part of the adjacent flange pile 1 to achieve stable abutment and not easy to overturn. The force on the retaining plate 3 is more stable. The shape of the retaining plate 3 is adapted to the shape of the connection part with the flange pile 1. In this embodiment, for example, the flange part and the side wall have chamfers, and the corresponding positions of the retaining plate 3 are also provided with chamfers. The top surface position of the retaining plate 3 is adapted to the top surface position of the flange pile 1. The height of the flange pile 1 is adapted to the height of the platform area of the slope 2. The ground between the adjacent two flange piles 1 is closed with a concrete layer, effectively leveling the ground and facilitating the installation of the retaining plate 3 and the dense connection at the ground. Or, the bottom end of the retaining plate 3 can also extend into the ground to enhance the stability of the retaining plate 3, and then there is no need to use a concrete layer for closing.

[0037] Specifically, as Figures 2 - 3 shown, a number of drain holes 4 are provided in the retaining plate 3 to facilitate the drainage of water into the side ditch on the roadbed. A filter layer 5 is provided on the side of the retaining plate 3 close to the corresponding slope 2. The filter layer 5 includes bagged sand and gravel. A drainage net 6 is provided between the retaining plate 3 and the filter layer 5 to effectively prevent soil and stone slag from entering the drain holes 4 and causing blockage of the drain holes.

[0038] Preferably, the top surface of the retaining structure is closed with a concrete layer, and the concrete layer extends to the platform area of the slope 2.

[0039] The retaining plate 3 between the adjacent two flange piles 1 adopts an L-shaped structure. The two L-shaped sections are respectively connected to the corresponding flange parts. The flange piles 1 arranged in a staggered manner and the retaining plate 3 with a straight lap between them effectively disperse the soil pressure received by the retaining plate 3 to the adjacent two flange piles 1, effectively avoiding the dislocation between the retaining plate 3 and the flange pile 1, eliminating the weak links of the traditional pile-plate structure, ensuring the stability of the retaining system, and enabling the flange pile 1 close to the end wall 7 to fit more closely with the tunnel portal end wall, thereby better protecting the end wall 7 and effectively improving the safety and reliability.

[0040] The construction method of adopting the above retaining structure includes the following steps:

[0041] a. Construct the lock joint of the flange pile 1, excavate the pile hole of the flange pile 1, construct the retaining wall as excavation progresses, and construct the flange pile 1;

[0042] b. After all the flange piles 1 are constructed, vertically excavate the rock and soil on the side of the flange pile 1 adjacent to the road and the slope 2 between two adjacent flange piles 1;

[0043] c. Demolish the lock joint and the retaining wall, spray and seal the ground between two adjacent flange piles 1 with concrete, and the thickness of the concrete layer is 0.1 - 0.15 m;

[0044] d. Set the filter layer 5 and the drainage net 6 in layers. The height of each layer of the filter layer 5 and the drainage net 6 is 0.5 - 1 m, and set the retaining plates 3 in layers, that is, set a layer of the filter layer 5 and the drainage net 6 and then correspondingly set a layer of the retaining plate 3, and then continue to set the next layer of the filter layer 5 and the drainage net 6 and the corresponding retaining plate 3 until the predetermined elevation from bottom to top. After all the retaining plates 3 on the road surface side are installed, spray and seal the top surface of the retaining structure with concrete, and the thickness of the concrete layer is 0.1 - 0.15 m to complete the retaining of the slope 2.

[0045] Adopting the construction method of a trumpet-shaped slope retaining structure at the tunnel entrance of the present invention, first construct the flange pile 1, then excavate the rock and soil of the slope 2 in front of and between the piles, which is beneficial to reducing the construction risk, and then set the filter layer 5 and the drainage net 6 behind the retaining plate 3, which is beneficial to reducing the construction difficulty of the retaining plate 3, effectively improving the construction efficiency, being beneficial to ensuring the stable connection between the retaining plate 3 and the flange pile 1, reducing the risk of displacement and dislocation, and improving the stability of the retaining structure.

[0046] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A trumpet-shaped slope retaining structure at the tunnel entrance, characterized in that The invention comprises flange piles (1), wherein the flange piles (1) are arranged on the inner side of a slope (2), the flange piles (1) are spaced apart along the direction of the corresponding slope (2), the flange part of the flange piles (1) is located on a side away from the corresponding slope (2), an L-shaped retaining plate (3) is connected between two adjacent flange piles (1) on the same side, the two ends of the retaining plate (3) are respectively connected to the flange part of the corresponding flange pile (1), the top surface position of the retaining plate (3) is matched with the top surface position of the flange pile (1), the height of the flange pile (1) is matched with the height of the platform area of the slope (2), the top surface of the retaining structure is sealed with a concrete layer, and the ground between two adjacent flange piles (1) is sealed with a concrete layer.

2. The retaining structure according to claim 1, characterized in that The retaining plate (3) is provided with a plurality of drainage holes (4).

3. The retaining structure according to claim 2, wherein A filter layer (5) is provided on the side of the retaining plate (3) close to the corresponding side slope (2), and a drainage net (6) is provided between the retaining plate (3) and the filter layer (5).

4. The retaining structure according to claim 3, characterized in that, The filter layer (5) comprises bagged sand and pebbles.

5. The retaining structure according to any one of claims 1-4, characterized in that, The bottom end of the retaining plate (3) extends into the ground.

6. A construction method of a trumpet-shaped slope retaining structure at the tunnel entrance as described in any one of claims 3-4, characterized in that, The following steps are included: a. constructing the locking mouth of the flange pile (1), excavating the pile hole of the flange pile (1), constructing the retaining wall as the excavation progresses, and constructing the flange pile (1); b. After the construction of all the flange piles (1) is completed, vertical excavation of the rock and soil of the slope (2) on the road side of the flange piles (1) and between two adjacent flange piles (1); c. Remove the lock and the protective wall; d. The filter layer (5) and the drainage net (6) are arranged in layers, and the retaining plate (3) is arranged in layers, wherein the filter layer (5) and the drainage net (6) are arranged on a side of the retaining plate (3) close to the slope (2), so as to support the slope (2).

7. The construction method according to claim 6, characterized in that, After the lock and the protective wall are removed, the ground between two adjacent flange piles (1) is sealed with a concrete layer, and after the retaining plate (3) is installed, the top surface of the retaining structure is sealed with a concrete layer.

8. The construction method according to claim 6, characterized in that, The height of each layer of the filter layer (5) and the drainage net (6) is 0.5-1 m.

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