A highly permeable road cut retaining wall structure

Abstract

This utility model discloses a highly permeable retaining wall structure for road cuts. The structure includes a wall body segmented with settlement joints, an internal drainage system, and a multi-stage reverse filtration drainage system along the entire height of the wall back. The multi-stage reverse filtration drainage system, from the wall body towards the backfill soil, consists of a permeable geotextile isolation layer, a first-stage coarse gravel reverse filtration layer, a second-stage medium gravel reverse filtration layer, and a third-stage fine gravel reverse filtration layer. Geogrids are installed between each reverse filtration layer, and a permeable geotextile isolation layer is also installed between the third-stage fine gravel reverse filtration layer and the backfill soil. The drainage system includes multiple rows of drainage pipes extending into the first-stage coarse gravel reverse filtration layer, each with permeable geotextile filter sleeves at its inlet ends. This utility model, through the combination of multi-layer reverse filtration and three-dimensional drainage, forms a highly efficient and clogging-resistant drainage channel, rapidly draining water accumulated behind the wall, greatly reducing hydrostatic pressure, and significantly improving the long-term stability and safety of the retaining wall.

Description

Technical Field

[0001] This utility model relates to the fields of geotechnical engineering and road engineering technology, specifically to a highly permeable retaining wall structure for road cut slopes. Background Technology

[0002] In road construction, retaining walls are crucial structures for protecting the stability of cut slopes and preventing collapse. These retaining walls bear the pressure of the backfill soil behind them for extended periods. Rainwater infiltration or rising groundwater levels increase the water content of the soil behind the wall, increasing its weight and strength, and significantly raising the hydrostatic pressure. This can easily lead to cracking, settlement, or even instability, seriously threatening road safety. Common drainage measures, such as single or multiple rows of drain pipes and filter layers, are inefficient and fail to quickly drain large amounts of water behind the wall. When soil particles are lost, the filter layer becomes ineffective, and the drain holes are easily blocked, especially in areas with abundant rainfall or high groundwater levels. Therefore, there is an urgent need for a retaining wall structure with a more scientifically designed internal drainage system, high permeability, and long-term stability. Utility Model Content

[0003] To address the aforementioned shortcomings, this utility model aims to provide a highly permeable road cut retaining wall structure. Through an innovative multi-layer collaborative drainage design, it solves the problem of water accumulation behind the wall and significantly improves the long-term stability of the retaining wall.

[0004] To achieve the above technical objectives, the following technical solutions were adopted: A highly permeable road cut retaining wall structure includes a wall body with an internal drainage system. The wall body is segmented along its length, with settlement joints between adjacent segments. At the back of the wall body, a multi-stage reverse filtration drainage system is installed along the entire height of the wall body. The multi-stage reverse filtration drainage system, from the wall body towards the backfill soil, sequentially includes a permeable geotextile isolation layer, a first-stage coarse gravel reverse filtration layer, a second-stage medium gravel reverse filtration layer, and a third-stage fine gravel reverse filtration layer. The drainage system includes multiple rows of drainage pipes extending into the multi-stage reverse filtration drainage system.

[0005] Furthermore, geogrids are provided between the gravel filter layers for physical separation.

[0006] Furthermore, a permeable geotextile isolation layer is laid between the third-stage fine gravel filter layer and the backfill soil.

[0007] Furthermore, the thickness of the first-stage coarse gravel filter layer is 150-200 mm, the thickness of the second-stage medium gravel filter layer is 100-150 mm, and the thickness of the third-stage fine gravel filter layer is 100-150 mm.

[0008] Furthermore, the drain pipe is a rigid PVC pipe with seepage holes on the pipe wall at the inlet end, and the drain pipes are arranged on the wall in a staggered, quincunx pattern.

[0009] Furthermore, the inlet end of the drain pipe extends into the first-stage coarse gravel filter layer of the multi-stage reverse filtration drainage system.

[0010] Furthermore, the inlet end of the drain pipe is wrapped with a permeable geotextile filter sleeve.

[0011] Furthermore, the settlement joint is filled with asphalt-impregnated hemp fiber or closed-cell foam plastic board.

[0012] Furthermore, the wall is provided with a front ditch, and the outlet of the lowest row of drain pipes is at least 0.3 meters higher than the designed water level of the front ditch.

[0013] Furthermore, the wall is constructed by layering C20 rubble concrete.

[0014] The beneficial effects achieved by this utility model are: This invention provides a highly permeable retaining wall structure for road cuts. Compared with existing technologies, this invention employs a multi-stage reverse filtration drainage system. Coarse, medium, and fine gravel layers, separated by geogrids, form a gradient-based, highly permeable drainage channel that efficiently collects and guides water behind the wall. A quincunx-shaped arrangement of drainage pipes, combined with a continuous filter layer covering the entire wall height, forms a three-dimensional network drainage system that rapidly discharges groundwater at different depths, significantly reducing hydrostatic pressure behind the wall and fundamentally ensuring the stability and safety of the retaining wall. Furthermore, the synergistic effect of multiple layers of geotextile (isolation layer, protective layer, filter sleeve) and a strictly graded multi-layered filter effectively prevents fine soil particles from entering and clogging the drainage channels, ensuring the long-term effectiveness of the drainage system. The layered concrete wall and settlement joint system effectively control uneven settlement, preventing structural cracking from potentially damaging the drainage system. The C20 rubble concrete, geogrid, geotextile and other materials used in this utility model are all commonly used engineering materials, easy to obtain and low in cost; at the same time, the construction technology of each structural part is mature, the construction difficulty is small and the efficiency is high, which makes it easy to promote and apply in various road cutting projects, and has good technical and economic benefits. Attached Figure Description

[0015] The present invention will now be described in conjunction with the accompanying drawings.

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of this utility model.

[0017] Figure 2 This is a front structural diagram of the present invention.

[0018] Figure 3 This is a cross-sectional schematic diagram of the multi-stage reverse filtration drainage system described in this utility model.

[0019] Figure 4 This is a partially enlarged view of the inlet end of the drain pipe described in this utility model.

[0020] In the diagram: 1-wall body; 2-drainage pipe; 21-seepage hole; 3-multi-stage reverse filtration drainage system; 31-permeable geotextile isolation layer; 32-first-stage coarse gravel reverse filtration layer; 33-second-stage medium gravel reverse filtration layer; 34-third-stage fine gravel reverse filtration layer; 35-geogrid; 4-settlement joint; 5-ditch in front of the wall; 6-backfill soil. Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. The described embodiments are merely some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] like Figure 1-3 As shown, the present invention discloses a highly permeable road cut retaining wall structure, comprising a wall body 1 formed by layered pouring of C20 rubble concrete. The wall body 1 is divided into sections along its length, and settlement joints 4 are provided between adjacent sections. The settlement joints 4 are filled with asphalt hemp fiber or closed-cell foam plastic board. The wall body 1 is also provided with a front wall ditch 5.

[0023] A multi-stage reverse filtration drainage system 3 is installed close to the back of the wall 1, extending along the entire height of the wall 1. This system, from the wall 1 towards the backfill soil, sequentially includes a permeable geotextile isolation layer 31, a 150mm thick first-stage coarse gravel reverse filtration layer 32, a 100mm thick second-stage medium gravel reverse filtration layer 33, and a 100mm thick third-stage fine gravel reverse filtration layer 34. Geogrids 35 are installed between each level of gravel reverse filtration layer to effectively prevent adjacent gravel materials from mixing due to vibration or compaction, maintaining the gradation stability and permeability of each reverse filtration layer. A permeable geotextile isolation layer 31 is also installed between the third-stage fine gravel reverse filtration layer 34 and the backfill soil 6.

[0024] A drainage system is installed inside the wall 1, consisting of several rows of rigid PVC drainage pipes 2 arranged in a staggered, quincunx pattern. Seepage holes 21 are formed in the pipe wall at the inlet end of each drainage pipe 2. The inlet end of the drainage pipe 2 passes through a permeable geotextile isolation layer 31 and extends into the first-stage coarse gravel filter layer 32 to efficiently collect the groundwater flowing there. The inlet end of the drainage pipe 2 is tightly wrapped with a permeable geotextile filter sleeve to prevent gravel or soil particles from entering the pipe and causing blockage. The drainage pipe 2 slopes outwards at a certain angle, and its outlet should be at least 0.3 meters above the design water level of the ditch 5 in front of the wall.

[0025] The construction steps of this utility model are as follows: 1. Excavation and foundation treatment: Excavate the retaining wall foundation pit according to the design drawings. After the foundation pit is excavated to the design elevation, the foundation is compacted with a compaction degree of not less than 95%. If the foundation is a soft soil layer, graded sand and gravel are used for replacement. The replacement depth is 1m, and the soil is compacted in layers.

[0026] 2. Wall body 1 pouring and settlement joint 4 setting: The wall body formwork is erected according to the segment length. After the wall body reinforcement is tied, C20 rubble concrete is poured in layers. After each layer is poured, an immersion vibrator is used to compact it until no air bubbles overflow from the concrete surface. Settlement joint 4 is set at the segment. A 20mm thick foam plastic board is used as the settlement joint partition. After the concrete is poured, the foam board is removed, asphalt hemp rope is filled in and compacted.

[0027] 3. Laying of multi-stage reverse filtration drainage system 3: After the concrete of the wall 1 is poured to a certain height (after every 2m of wall 1 is poured, the corresponding height of multi-stage reverse filtration system 3 is laid), a permeable geotextile isolation layer 31 is laid on the back surface of the wall. The geotextile is fixed to the wall concrete with cement nails at a spacing of 500mm. Then, the first-stage coarse gravel reverse filtration layer 32, geogrid 35, the second-stage medium gravel reverse filtration layer 33, geogrid 35, and the third-stage fine gravel reverse filtration layer 34 are laid in sequence. After each gravel reverse filtration layer is laid, it is lightly vibrated with a plate vibrator to ensure uniform layer thickness. Finally, a permeable geotextile isolation layer 31 is laid on the surface of the third-stage fine gravel reverse filtration layer 34. The contact side between the geotextile and the backfill soil 6 is temporarily compacted with backfill soil.

[0028] 4. Installation of Drainage Pipe 2: During the concrete pouring of the wall, drainage pipe 2 is pre-embedded according to the design position. Before installation, check whether the seepage holes are unobstructed. Wrap the inlet end with a permeable geotextile filter sleeve and tie it firmly. During installation, ensure that the axis of drainage pipe 2 is at a 30° angle with the wall (to facilitate drainage). The inlet end is accurately inserted into the first-stage coarse gravel filter layer 32, and the outlet end extends 100mm beyond the outside of the wall. The elevation of the lowest drainage pipe outlet meets the design requirements. The joint between drainage pipe 2 and the concrete of wall 1 is sealed with waterproof sealant to prevent rainwater from seeping into the interior of the wall.

[0029] 5. Backfilling behind the wall and construction of the side ditch in front of the wall: After the multi-stage reverse filter drainage system 3 is laid, backfilling is carried out behind the wall. The backfill soil is permeable sandy soil, backfilled in layers, with each layer being 300mm thick. A small road roller is used to compact the soil, with a compaction degree of not less than 93%. At the same time, the side ditch in front of the wall 5 is constructed according to the design drawings. After the construction is completed, the cross-sectional dimensions and longitudinal slope of the ditch are checked to ensure smooth drainage.

[0030] 6. Acceptance and maintenance: After construction is completed, conduct an external inspection of the retaining wall structure to ensure that there are no obvious cracks in the wall body 1, the settlement joint 4 is tightly filled, and the drainage pipe 2 is not blocked. During the rainy season, regularly check the drainage of the drainage pipe 2 and the water accumulation in the ditch 5 in front of the wall. If the drainage of the drainage pipe 2 is found to be obstructed, clean the impurities on the permeable geotextile filter sleeve in time to ensure the normal operation of the drainage system.

[0031] Other aspects of this utility model that are not detailed herein are all conventional techniques known to those skilled in the art.

[0032] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] The scope of protection of this utility model is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this utility model shall fall within the scope of protection of this utility model.

Claims

1. A high permeable road cutting retaining wall structure, comprising a wall body (1), a drainage system is arranged inside the wall body (1), the wall body (1) is arranged in sections along the length direction, and a settlement joint (4) is arranged between adjacent sections; characterized in that: At the back of the wall (1), a multi-stage reverse filtration drainage system (3) is provided along the entire height of the wall (1). The multi-stage reverse filtration drainage system (3) includes a permeable geotextile isolation layer (31), a first-stage coarse gravel reverse filtration layer (32), a second-stage medium gravel reverse filtration layer (33), and a third-stage fine gravel reverse filtration layer (34) in sequence from the wall (1) toward the backfill soil (6). The drainage system includes multiple rows of drainage pipes (2) extending into the multi-stage reverse filtration drainage system (3).

2. The highly permeable cut retaining wall structure according to claim 1, characterized in that: Geogrids (35) are provided between the gravel filter layers for physical separation.

3. The highly permeable cut retaining wall structure according to claim 2, characterized in that: A permeable geotextile isolation layer (31) is also laid between the third-level fine gravel filter layer (34) and the backfill soil (6).

4. The highly permeable cut retaining wall structure according to claim 3, characterized in that: The thickness of the first-stage coarse gravel filter layer (32) is 150-200 mm, the thickness of the second-stage medium gravel filter layer (33) is 100-150 mm, and the thickness of the third-stage fine gravel filter layer (34) is 100-150 mm.

5. A highly permeable cut retaining wall structure according to claim 1, characterized in that: The drain pipe (2) is a rigid PVC pipe with a seepage hole (21) on the pipe wall at the inlet end. The drain pipe (2) is arranged on the wall (1) in a staggered quincunx pattern.

6. A highly permeable cut retaining wall structure according to claim 5, characterized in that: The inlet end of the drain pipe (2) extends into the first coarse gravel filter layer (32) of the multi-stage reverse filtration drainage system (3).

7. A highly permeable cut retaining wall structure according to claim 6, characterized in that: The inlet end of the drain pipe (2) is wrapped with a permeable geotextile filter sleeve.

8. A highly permeable cut retaining wall structure according to claim 1, characterized in that: The settlement joint (4) is filled with asphalt hemp fiber or closed-cell foam plastic board.

9. A highly permeable road cut retaining wall structure according to claim 1, characterized in that: The wall (1) is provided with a wall front ditch (5), and the outlet height of the lowest drain pipe (2) is more than 0.3 meters higher than the design water level of the wall front ditch (5).

10. A highly permeable road cut retaining wall structure according to claim 1, characterized in that: The wall (1) is constructed by layering C20 rubble concrete.

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