Invisible drainage system, method and building wet area structure

Abstract

The invention discloses an invisible drainage system, a method and a building wet area structure. The invisible drainage system comprises a water collecting part and a drainage main pipeline. The water collecting part is provided with an inner cavity allowing water to enter and a water permeable wall communicated with the inner cavity, and the water permeable wall is constructed to allow water in the constructed filling layer to permeate and block solid particles; and the drainage main pipeline is in fluid communication with the inner cavity of the water collection part and is used for draining the collected water. The invention provides a wet area drainage solution which has great innovation from the design concept to the specific structure, fundamentally solves the common quality problems troubling constructional engineering for a long time, and has extremely high practicability, reliability and popularization value.

Description

Technical Field

[0001] This invention relates to the field of building engineering technology, specifically to an invisible drainage system, method, and building wet area structure. Background Technology

[0002] In damp areas of buildings such as kitchens, bathrooms, and balconies, tile (or stone) cladding layers (including adhesive and rigid layers) can accumulate water due to the seepage of domestic wastewater and rainwater through gaps in the surface. Because the underlying structural floor slab has a complete waterproofing layer, this "water" is trapped within the decorative filling layer and cannot leak downwards. The accumulated water spreads to the surrounding walls through capillary action, causing dampness, putty peeling, paint mold, and damage to the finish in adjacent rooms, severely impacting functionality and health. This problem is particularly pronounced when the waterproofing layer is intact and is difficult to resolve completely using traditional repair methods.

[0003] Existing solutions mainly rely on waterproofing layers to "plug leaks" or the use of traditional secondary drainage floor drains. However, the former cannot remove accumulated water; the latter is usually only for the backfill layer of sunken bathrooms, with a single drainage path, prone to clogging, and not suitable for non-sunken areas (such as balconies and kitchens) or lightweight backfilling processes, and cannot completely solve the problem of water accumulation in the tiled layer.

[0004] Therefore, there is an urgent need for an invisible drainage solution that can proactively, effectively, and persistently drain water accumulated in the structural filling layers of wet areas in buildings. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an invisible drainage system, structure and method that can actively drain water accumulated in the filling layer of a building's wet area, fundamentally eliminating problems such as dampness and mold in the walls caused by water accumulation in the layer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An invisible drainage system includes a water collection section and a main drainage pipe;

[0008] The water collection section has an internal cavity that allows water to enter and a permeable wall communicating with the internal cavity. The permeable wall is configured to allow water in the structural filling layer to seep in while blocking solid particles.

[0009] The main drainage pipe is in fluid communication with the internal cavity of the water collection section, and is used to drain the collected water away.

[0010] To effectively eliminate water accumulation within the structural filler layer and prevent drainage channels from being blocked by solid impurities such as cement mortar, this invention constructs the permeable wall of the water collection section as a structure with selective filtration functionality. Its working principle is as follows: when domestic water or rainwater seeps into the structural filler layer through the tile gaps, it accumulates and spreads within the layer.

[0011] In this invention, the water collection section is embedded within the structural filling layer, and its permeable wall is in direct contact with the surrounding structural filling layer material (such as mortar or backfill ceramsite). Driven by gravity, capillary action, and water pressure difference, the accumulated water in the structural filling layer converges towards the water collection section and penetrates the permeable wall into its internal cavity, while solid impurities such as cement particles and dust are effectively blocked outside the permeable wall. The accumulated water entering the cavity is then actively drained away through a connected main drainage pipe (such as the building's main drainage pipe or horizontal pipe), thus achieving "drainage" instead of "pure blocking" and eliminating the source of water accumulation.

[0012] In one alternative embodiment, the water collection section includes a vertical water collection element, and the permeable wall is located in the upper region of the side wall of the vertical water collection element.

[0013] In one alternative embodiment, the upper end of the vertical water collection component is configured to connect to a floor drain panel or a floor drain core.

[0014] In one optional embodiment, the water collection part further includes a water collection pipe, the end of which is provided with a water-permeable structure, the water-permeable structure being configured to allow water in the filling layer to seep in while blocking solid particles; the lower end of the vertical water collection element is in fluid communication with the water collection pipe.

[0015] In one alternative implementation, one end of the water collection pipe is connected to the main drainage pipe.

[0016] In one alternative embodiment, the permeable wall includes an open structure and a filter layer covering the outer layer of the open structure; the open structure is a plurality of holes or at least one slit.

[0017] In one alternative embodiment, the filter layer is a geotextile or a nonwoven fabric.

[0018] In one alternative embodiment, the water collection pipe is laid within a drainage channel made of permeable material.

[0019] This embodiment also provides a building wet area structure, including a main structural layer, a waterproof layer, a structural filling layer above the waterproof layer, and a surface layer. The structure is provided with an invisible drainage system as described above, wherein the water collection part is at least partially embedded in the adhesive layer of the structural filling layer and / or the surface layer.

[0020] This embodiment also provides a drainage method for the structural filling layer of a building wet area, including the following steps:

[0021] Lay the main drainage pipe on top of the waterproof layer in the building's wet areas;

[0022] Install a water collection section so that its permeable wall can contact the interior of the wet area structure filling layer, and connect the water collection section to the main drainage pipe;

[0023] Subsequent structural filling layer construction is carried out so that the permeable wall of the water collection section is covered in the structural filling layer material; wherein, water that seeps into the interior of the structural filling layer enters the water collection section through the permeable wall and is discharged through the main drainage pipe.

[0024] The beneficial effects that the concealed drainage system, method, and building wetland structure disclosed in this application may bring include, but are not limited to:

[0025] 1. It completely changes the passive approach of relying solely on "waterproofing" and innovatively adopts a systematic solution that combines prevention and drainage, with drainage as a supplement. It actively drains water that has seeped into the structural filling layer, eliminating the "source of water" that causes damp walls and moldy finishes from the root, achieving a permanent prevention effect.

[0026] 2. The unique "permeable wall + filter layer" design is the core guarantee for the system's long-term effectiveness. It can continuously filter impurities and prevent drainage holes from clogging during the decades-long lifespan of a building, solving the fatal weakness of traditional secondary drainage floor drains that are prone to failure, and ensuring the durability and reliability of the drainage function.

[0027] 3. By combining vertical and horizontal water collection components, a three-dimensional, double-layered drainage network is constructed. This system can not only handle the accumulated water in the backfill layer of sunken bathrooms, but also effectively drain the hidden water under the tiled layer in non-sunken areas (such as balconies and kitchens). It has a wide range of applications and provides comprehensive protection.

[0028] 4. All drainage components are pre-embedded within the building's decorative surface and structural infill layer, making them completely invisible after completion. This does not affect the overall aesthetics or functionality of the floor tiles, achieving a perfect balance between functionality and aesthetics.

[0029] 5. The system can be seamlessly integrated into standard plumbing and electrical installations, waterproofing, backfilling and leveling, and tile laying, without requiring complex or specialized processes or large equipment. Prefabricated components simplify installation, ensure quality control, and facilitate widespread implementation in various construction projects.

[0030] 6. By keeping the interior of the structural fill layer dry, the risk of mold growth due to dampness inside the wall is greatly reduced, improving indoor air quality and occupant health. At the same time, a dry base layer protects the building structure and decorative materials, extending their lifespan and reducing later maintenance costs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the concealed drainage system provided in an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the permeable structure according to an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the permeable structure from another perspective in an embodiment of the present invention.

[0034] Figure 4 This is a partial enlarged view of the permeable wall according to an embodiment of the present invention.

[0035] Illustration: 1-Main structural layer, 2-Waterproof layer, 3-Lightweight backfill layer, 4-Rigid layer, 5-Adhesive layer, 6-Surface layer, 7-Vertical water collection component, 8-Water collection pipe, 9-Filter layer, 10-Perforated structure, 11-Permeable structure, 12-Drainage pipe, 13-Outer shell, 14-Permeable strip, 15-Geotextile layer, 16-Water inlet hole or water inlet strip. Detailed Implementation

[0036] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0037] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] like Figure 1-4 As shown, in a first aspect, an invisible drainage system for a structural fill layer in a building's wet area includes a water collection section and a main drainage pipe. The water collection section has an internal cavity that allows water to enter and a permeable wall communicating with the internal cavity. The permeable wall is configured to allow water from the structural fill layer to seep in while blocking solid particles. The main drainage pipe is in fluid communication with the internal cavity of the water collection section for draining the collected water.

[0039] To effectively eliminate water accumulation within the structural filler layer and prevent drainage channels from being blocked by solid impurities such as cement mortar, this invention constructs the permeable wall of the water collection section as a structure with selective filtration capabilities. Its working principle is as follows: when domestic water or rainwater seeps into the structural filler layer through the tile gaps, it accumulates and spreads within the layer. In this invention, the water collection section is pre-embedded within the structural filler layer, and its permeable wall is in direct contact with the surrounding structural filler material (such as mortar or backfill ceramsite). Driven by gravity, capillary action, and water pressure difference, the accumulated water within the structural filler layer converges towards the water collection section and penetrates the permeable wall into its internal cavity, while solid impurities such as cement particles and dust are effectively blocked outside the permeable wall. The accumulated water entering the cavity is then actively drained away through a connected main drainage pipe (such as the building's main drainage pipe or horizontal pipe), thus achieving "drainage" instead of "pure blockage" and eliminating the source of water accumulation.

[0040] As a further improvement to the above technical solution, the water collection part includes a vertical water collection component 7, and the permeable wall is located in the upper part of the side wall of the vertical water collection component 7.

[0041] To specifically address the technical problem of water accumulation and drainage within the tile paving layer, this invention incorporates a vertical water collection component 7. The permeable wall is positioned on the upper part of its sidewall to ensure that, after tile installation, the permeable area is tightly surrounded by tile adhesive or cement mortar, thus directly "inserting" into the paving layer, the primary "water storage layer."

[0042] The working process is as follows: water seeping in from the tile gaps spreads horizontally within the paving layer. When it comes into contact with the permeable wall of the vertical water collection component 7, it penetrates the filter layer 9 and enters the water collection component, then flows downward along its internal cavity.

[0043] It should be noted that the vertical water collection component 7 can be an independent pipe or an integral design with the drain base; its cross-sectional shape can be circular, square or other polygonal.

[0044] As a further improvement to the above technical solution, the upper end of the vertical water collection component 7 is configured to connect to the floor drain panel or floor drain core.

[0045] To facilitate inspection and maintenance, and to integrate the system with standard interior finishes for a unified appearance, the upper part of the vertical water collection unit 7 is designed to connect to a floor drain. This allows water accumulation on the decorative layer (such as tiles) and below to be collected through the floor drain and collection unit and drained into the main drainage pipe. Furthermore, any blockages below can be easily cleared by opening the floor drain cover.

[0046] As a further improvement to the above technical solution, the water collection section also includes a water collection pipe 8. The end of the water collection pipe 8 is equipped with a permeable structure 11. The lower end of the vertical water collection component 7 is in fluid communication with the water collection pipe 8, and one end of the water collection pipe 8 is connected to the main drainage pipe. To ensure that all collected water can be ultimately drained away from the building, the water collection pipe 8 needs to be connected to the building's existing drainage system. Typically, one end is connected to the main drainage pipe or a pre-installed drainage interface in areas such as bathrooms or balconies, forming an organized drainage path.

[0047] It should be noted that the water-permeable structure 11 provided at the end of the water collection pipe 8 includes a number of water inlet holes or water inlet slots 16 opened at the end of the water collection pipe 8 for water inlet, and a filter structure provided outside these water inlet holes or water inlet slots 16. The main function of the filter structure here is to allow water to seep in while blocking solid particles and other materials.

[0048] Specifically, the filter structure includes a PVC pipe outer shell 13, which is located at the end of the water collection pipe 8. The outer shell 13 has several permeable strips 14, and a receiving cavity is formed between the outer shell 13 and the water collection pipe 8. Several water inlet holes or water inlet slits 16 at the end of the water collection pipe 8 are located within this receiving cavity. Several geotextile layers 15 are installed within the receiving cavity. It should be noted that the openings at the end of the water collection pipe 8 are located at the end of the pipe body (approximately from 10 o'clock to 2 o'clock). This minimizes the possibility of backflow from the water inlet holes.

[0049] For ease of assembly on site, the filter structure can be pre-connected to the main drainage pipe. Specifically, a section of guide pipe 12 is connected to the bottom of the outer shell 13, with one end of the guide pipe 12 connected to the main drainage pipe. Several water inlet holes or water inlet slots 16 are opened above the guide pipe 12, and several geotextile layers 15 are also arranged in the cavity between the outer shell 13 and the guide pipe 12. During installation, the end of the water collection pipe 8 is directly inserted into the guide pipe 12 and then glued.

[0050] To address the drainage challenge of large-area water accumulation in the lower structural filling layers such as backfill or bedding layers, and to achieve systematic integration with the upper drainage system, this invention adds a water collection pipe 8. The permeable structure 11 is positioned at the end of the pipe to allow water seeping down from the upper layer to efficiently enter the pipe from the end. Its working principle is as follows: water in the lower structural filling layer seeps downwards; due to the inclined surface of the waterproof layer 2, the water collects at the filter structure, and then seeps into the pipe through the permeable structure 11 at its end. Water collected by the vertical water collection element 7 flows from its lower end into the water collection pipe 8, where the two converge.

[0051] Collaborative working process: The system forms a double-layer drainage network of "point (vertical water collection component 7) and line (water collection pipe 8) combination". The vertical water collection component 7 is responsible for "vertically collecting" the water accumulated in the paving layer, and the water collection pipe 8 is responsible for "horizontally collecting" the water accumulated in the backfill / subbase layer and the drainage from the upper layer, so as to achieve all-round capture and drainage of water accumulated in the cross section (from top to bottom) of the entire wet area structural filling layer.

[0052] The water collection pipe 8 can be connected to the vertical water collection component 7 through fittings such as tees and elbows, or the lower section of the vertical water collection component 7 can be extended laterally and opened to directly form a horizontal water collection part.

[0053] As a further improvement to the above technical solution, the permeable wall includes an open structure 10 and a filter layer 9 covering the outer layer of the open structure 10; the open structure 10 is a plurality of holes or at least one slit.

[0054] To achieve reliable water flow and long-term anti-clogging function, this invention concretizes the permeable wall as a composite structure of "open structure 10 + filter layer 9". The open structure 10 provides the physical channel for water flow, while the outer filter layer 9 is key to achieving the "blocking" function. The working process is as follows: water first passes through the filter layer 9, then through the open structure 10 into the internal cavity. The filter layer 9 effectively blocks mortar particles, preventing the open structure 10 from becoming clogged.

[0055] The perforation structure 10 can be uniformly distributed round holes, elongated holes, or slots arranged along the pipe body; the gaps can be straight seams or arc-shaped seams. The filter layer 9 can be combined with the perforation structure 10 by wrapping, bonding, thermal bonding, or sleeve.

[0056] As a further improvement to the above technical solution, filter layer 9 is made of geotextile or non-woven fabric. To achieve excellent permeability and filtration accuracy, while ensuring material durability and economy, geotextile or non-woven fabric is preferred as the material for filter layer 9. These materials have numerous micropores, allowing water molecules to pass freely while effectively intercepting fine particles such as cement. They are also corrosion-resistant, not easily degraded, and have a lifespan comparable to that of the building. Equivalent alternative materials include other permeable filter fabrics or synthetic materials with similar functions.

[0057] As a further improvement to the above technical solution, the water collection pipe 8 is laid in a drainage channel made of permeable material.

[0058] To further improve drainage efficiency, prevent backfill material from compressing and partially clogging the permeable wall of the water collection pipe 8, and provide a flow guiding space for water collection, a dedicated drainage channel is set up. The water collection pipe 8 is placed in this channel. Its working principle is as follows: large-area water accumulation from the backfill layer first quickly collects into the channel formed by the permeable material (such as gravel), and then collects at the permeable structure 11, infiltrating through the filter structure of the water collection pipe 8.

[0059] Specifically, the drainage channel can be a prefabricated perforated plastic or concrete sleeve, hollow inside or filled with gravel; the permeable material can also be coarse sand or special drainage particles.

[0060] This embodiment also provides a building wet area structure, including a main structural layer 1, a waterproof layer 2, a structural filling layer located above the waterproof layer 2, and a surface layer 6. The structure is provided with an invisible drainage system as claimed in any of the preceding claims, wherein the water collection part is at least partially embedded in the adhesive layer of the structural filling layer and / or the surface layer 6.

[0061] The structural filling layer includes a lightweight backfill layer 3, a rigid layer 4, and an adhesive layer 5, which are sequentially disposed on the waterproof layer 2.

[0062] To integrate the aforementioned drainage system into the building, forming a fundamentally moisture-proof building structure for damp areas, this invention defines the integration method of the drainage system within the building structure. The positional relationship is as follows: the structural filling layer is located above the waterproof layer 2; the permeable wall or permeable structure 11 of the water collection part (vertical water collection element 7 and / or water collection pipe 8) is partially embedded within the target structural filling layer requiring drainage (e.g., the water collection pipe 8 is embedded in the backfill layer, and the permeable section of the vertical water collection element 7 is embedded within the rigid layer 4 and the adhesive layer 5), thus directly contacting the water storage environment. This structure allows water to be captured and discharged at the point of generation, achieving a fundamental solution through a combination of prevention and drainage.

[0063] The core working principle of this invention lies in "active guidance, layered collection, and filtering to prevent blockage".

[0064] The establishment of an active drainage mechanism: Traditional wetland structures rely solely on the bottom waterproof layer 2 for "passive blocking," while this invention embeds dedicated "water collection sections" within the structural filling layer above the waterproof layer 2. These water collection sections are in direct contact with the surrounding structural materials through their "permeable walls," essentially inserting "suction pipes" into a "reservoir." When water seeps into the structural filling layer for various reasons, it no longer accumulates randomly but is guided to these pre-designed drainage channels.

[0065] Layered collection and confluence: Through the coordinated design of vertical water collection components 7 and water collection pipes 8, the system achieves three-dimensional drainage of the structural filling layer cross section from top to bottom.

[0066] Vertical water collection component 7: The permeable wall on the upper part of its side wall mainly intercepts and collects water that seeps down from the gaps in the surface layer 6 and spreads laterally in the tile laying layer (adhesive layer) and rigid layer 4.

[0067] Water collection pipe 8: Its end permeable structure 11 mainly collects water that seeps down from the upper layer or enters the backfill layer below through other means.

[0068] The two are connected by pipes and eventually converge into the main drainage pipe (building's main riser). This process simulates the drainage pattern of "tributaries flowing into the main stream" in nature, which is efficient and orderly.

[0069] The filtration and anti-clogging mechanism: The permeable wall and permeable structure 11 critically integrate a filter layer 9 (such as geotextile). Its working process is as follows: liquid water in the filling layer can freely pass through the micropores of the filter layer 9 under a slight pressure difference, while solid particles such as silt and cement slurry carried by it are effectively blocked. This ensures that water can "only enter and not exit" (referring to solids), keeping the drainage channel unobstructed in the long term and avoiding system failure due to clogging.

[0070] In simple terms, its working process is as follows: water seeps in → diffuses within the structural filling layer → contacts the permeable wall of the water collection section and the permeable structure 11 → water penetrates the filter layer 9, impurities are blocked → clean water enters the pipe cavity (vertical water collection component 7 and water collection pipe 8) → flows to the main drainage pipe → is discharged out of the building system.

[0071] This embodiment also provides a drainage method for the structural filling layer of a building wet area, including the following steps:

[0072] A horizontal drainage pipe is laid on the waterproof layer 2 of the building's wet area; a water collection unit is installed so that its permeable wall can contact the interior of the wet area's structural filling layer, and the water collection unit is connected to the horizontal drainage pipe; subsequent structural filling layer construction is carried out so that the permeable wall of the water collection unit is covered in the structural filling layer material; water that seeps into the interior of the structural filling layer enters the water collection unit through the permeable wall and is discharged through the horizontal drainage pipe.

[0073] The specific construction steps are as follows:

[0074] S1: Apply waterproof layer 2 on the main structural layer 1 after the slope has been found;

[0075] S2: Lay a horizontal drainage pipe (with a permeable structure 11) on the waterproof layer 2 and connect it to the main drainage pipe according to the slope;

[0076] S3: Construct a lightweight backfill layer 3 to cover the horizontal drainage pipe;

[0077] S4: Construct a rigid layer 4 on the lightweight backfill layer 3, and install a vertical water collection component 7 (with a permeable wall) at the preset floor drain position, connecting its lower end to the horizontal drain pipe;

[0078] S5: Securely seal around the vertical water collection component 7;

[0079] S6: Apply adhesive layer 5 (tile adhesive, mortar) and lay the tiles. The tile adhesive or mortar will wrap around the side wall of the vertical water collection component 7.

[0080] S7: Install the drain core and cover plate at the top of the vertical drainage component.

[0081] To provide a standardized construction process for achieving the aforementioned structural and system functions, this invention summarizes a core drainage method. The key to this method is the pre-arrangement of a water collection section with a permeable wall after waterproofing and before or during the construction of each structural filling layer, ensuring its connection to the final drainage pipe. During subsequent construction, the structural filling layer material is allowed to naturally cover the water collection section, integrating it with the water storage layer. This process continues throughout the building's lifespan: any water that seeps into the structural filling layer will be automatically discharged following the pre-defined path (permeable wall → water collection section → main drainage pipe). The method's steps are clear and can be well integrated with traditional decoration procedures.

[0082] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A concealed drainage system, characterized in that, Including the water collection section and the main drainage pipe; The water collection section has an internal cavity that allows water to enter and a permeable wall communicating with the internal cavity. The permeable wall is configured to allow water in the structural filling layer to seep in while blocking solid particles. The main drainage pipe is in fluid communication with the internal cavity of the water collection section, and is used to drain the collected water away.

2. The concealed drainage system according to claim 1, characterized in that, The water collection section includes a vertical water collection component (7), and the permeable wall is located in the upper part of the side wall of the vertical water collection component (7).

3. The concealed drainage system according to claim 2, characterized in that, The upper end of the vertical water collection component (7) is configured to connect to a floor drain panel or floor drain core.

4. The concealed drainage system according to claim 2 or 3, characterized in that, The water collection section also includes a water collection pipe (8), and the end of the water collection pipe (8) is provided with a water-permeable structure (11). The water-permeable structure (11) is configured to allow water in the filling layer to seep in while blocking solid particles. The lower end of the vertical water collection component (7) is in fluid communication with the water collection pipe (8).

5. The concealed drainage system according to claim 4, characterized in that, One end of the water collection pipe (8) is connected to the main drainage pipe.

6. The concealed drainage system according to any one of claims 1 to 5, characterized in that, The permeable wall includes an open structure (10) and a filter layer (9) covering the outside of the open structure (10); the open structure (10) is a plurality of holes or at least one slit.

7. The concealed drainage system according to claim 6, characterized in that, The filter layer (9) is geotextile or non-woven fabric.

8. The concealed drainage system according to claim 4, characterized in that, The water collection pipe (8) is laid in a drainage channel made of permeable material.

9. A building wet area structure, comprising, from bottom right to top, a main structural layer (1), a waterproof layer (2), a layer located on the waterproof layer (2), and a surface layer (6), characterized in that, The structure is provided with an invisible drainage system as described in any one of claims 1 to 8, wherein the water collection part is at least partially embedded in the structure filling layer and / or the adhesive layer of the surface layer (6).

10. A drainage method for a structural filling layer in a building's wet area, characterized in that, Includes the following steps: The main drainage pipe is laid on top of the waterproof layer (2) in the wet area of ​​the building; Install a water collection section so that its permeable wall can contact the interior of the wet area structure filling layer, and connect the water collection section to the main drainage pipe; Subsequent structural filling layer construction is carried out so that the permeable wall of the water collection part is covered in the structural filling layer material; Water that seeps into the filling layer enters the water collection section through the permeable wall and is discharged through the main drainage pipe.

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