Roadbed structure with water-immersed roadbed drainage system

Abstract

The invention relates to the technical field of roadbed drainage structures, and discloses a roadbed structure with an immersed roadbed drainage system, the immersed roadbed drainage system is arranged in the roadbed structure and comprises a U-shaped sewer and an inclined pipe with holes, the U-shaped sewer comprises a vertical sewer and a transverse sewer, the top end of the vertical sewer extends to the top of the roadbed, and the transverse sewer is communicated with the bottom end of the vertical sewer. A perforated pipeline is arranged in the middle of the transverse seepage ditch in the length direction, the two sides of the perforated pipeline communicate with one ends of a plurality of perforated inclined pipes, and the other ends of the perforated inclined pipes extend out of the slope and are provided with duckbill valves; the electro-osmosis system is arranged in the side slope on the outer side of the vertical seepage ditch; the roadbed structure has good waterproof performance and drainage performance, and can be better applied to areas with dense river networks and high underground water level.

Description

Technical Field

[0001] The present invention relates to the technical field of subgrade drainage structures, and in particular to a subgrade structure with a submerged subgrade drainage system. Background Art

[0002] In the process of road construction, due to special geographical and climatic conditions in many areas, the problem of submerged subgrades has been plaguing. For example, in areas with dense river networks and high groundwater levels, a large amount of rainwater accumulates during the rainy season, resulting in the subgrade being immersed in water for a long time. The subgrades of newly built or existing roads are extremely vulnerable to being flooded. Being in a waterlogged environment for a long time, the stability and durability of the subgrade will be severely damaged. The particles in the subgrade soil gradually flow away under the scouring of water flow, resulting in a decrease in the strength of the subgrade and the appearance of settlement and cracks on the road surface. In cold regions, the water accumulates and freezes and expands, further exacerbating the damage to the subgrade structure and seriously affecting the normal use of the road.

[0003] The existing drainage systems configured for subgrade structures are difficult to play an effective role in the face of such severe submerged conditions. The drainage channels are simply designed and their drainage capacity quickly saturates during heavy rainfall or high water levels, and they cannot drain the accumulated water in the subgrade in time. These problems not only increase the maintenance cost of the road, shorten the service life of the road, but also pose a potential threat to traffic safety. To solve the drainage problem of submerged subgrades and ensure the safety and stability of the road, the submerged subgrade drainage system has emerged. However, the current submerged subgrade drainage system has poor drainage performance for the subgrade, and the moisture inside the subgrade drains slowly, and it cannot be applied in areas with dense river networks and high groundwater levels. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a subgrade structure with a submerged subgrade drainage system, which has good waterproof and drainage performance and can be better applied in areas with dense river networks and high groundwater levels.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] A subgrade structure with a submerged subgrade drainage system, in which a submerged subgrade drainage system is provided. The system includes a U-shaped infiltration ditch and a perforated inclined pipe. The U-shaped infiltration ditch includes a vertical infiltration ditch with its top extending to the top of the subgrade and a horizontal infiltration ditch connected to the bottom end of the vertical infiltration ditch. A perforated pipe is provided in the middle of the horizontal infiltration ditch along the length direction. Both sides of the perforated pipe are connected to one end of a number of perforated inclined pipes. The other end of the perforated inclined pipe extends to the outside of the slope and is provided with a duckbill valve. It further includes an electroosmosis system, which is arranged inside the slope outside the vertical infiltration ditch.

[0007] As a further implementation method, the vertical infiltration ditch is arranged near the positions of both shoulders of the road. The top of the vertical infiltration ditch is a permeable sealing layer, and the inside is filled with pervious fill.

[0008] As a further implementation method, the horizontal infiltration ditch is filled with a graded crushed stone layer, and the cross-sectional width of the horizontal infiltration ditch is greater than that of the vertical infiltration ditch.

[0009] As a further implementation method, the perforated pipe is arranged near the top of the horizontal infiltration ditch.

[0010] As a further implementation method, the electroosmosis system includes multiple groups of electrodes. Each group of electrodes includes an anode and a cathode. The cathode is arranged below the anode and near the upper part of the perforated inclined pipe. Each group of perforated inclined pipes is arranged corresponding to each group of electrodes.

[0011] As a further implementation method, it further includes a humidity sensor, which is arranged inside the slope of the roadbed. The humidity sensor and the electrodes are both connected to an external DC power supply and form a detection system. The detection system determines whether to turn on the DC power supply for electroosmotic drainage according to the detection data of the humidity sensor.

[0012] As a further implementation method, an HDPE pipe is provided on the duckbill valve at the end of the perforated inclined pipe for protection; a one-way drainage geotextile is coated on the perforated inclined pipe.

[0013] As a further implementation method, the slope of the roadbed is protected by concrete, and a waterproof coiled material is laid outside.

[0014] As a further implementation method, the roadbed is filled with roadbed soil, a layer of bentonite is laid on the upper layer of the roadbed, and a geotextile is laid below the bentonite.

[0015] As a further implementation method, the bottom of the roadbed is set as a sand and gravel cushion layer.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The U-shaped infiltration ditch, perforated inclined pipe, perforated pipe, and electroosmosis system provided inside the roadbed structure of the present invention jointly form a water interception and drainage channel. Part of the water entering the roadbed body seeps downward through the vertical infiltration ditch into the perforated inclined pipe, or enters the horizontal infiltration ditch, and then seeps into the perforated pipe or the perforated inclined pipe through the graded crushed stone layer. Part of the water is electroosmotically drained into the perforated inclined pipe and finally discharged through the duckbill valve; a bentonite layer is provided at the top surface of the roadbed, so that after absorbing water and swelling, it forms a waterproof layer. At the same time, the top of the vertical infiltration is a permeation sealing layer, which can effectively prevent water from entering the roadbed; a geotextile is laid under the bentonite to reduce the mixing of bentonite and roadbed soil and affect the performance; the slope of the roadbed is protected by concrete and a waterproof coiled material is laid outside, which can greatly reduce the infiltration of roadside ponding.

[0018] 2. The subgrade structure of the present invention adopts the method of external waterproofing and internal drainage, enabling the subgrade structure to have good waterproofing and drainage performance at the same time. The immersed subgrade drainage system uses the combined use of electroosmotic drainage and drainage pipeline drainage, which can quickly drain out the moisture, enabling this subgrade structure to be better applied in areas with dense river networks and relatively high groundwater levels.

[0019] 3. The shape of the infiltration ditch of the present invention is set as a U shape, including a vertical infiltration ditch and a horizontal infiltration ditch. The vertical infiltration ditch is filled with pervious granular materials to improve the downward water permeability speed; the horizontal infiltration ditch is arranged along the length direction of the subgrade and filled with a graded crushed stone layer, making it have good subgrade bearing capacity on the one hand and improve drainage performance on the other hand. When most of the moisture inside the subgrade reaches the horizontal infiltration ditch, it can further flow into the perforated inclined pipe and the perforated pipeline, and finally be discharged through the duckbill valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0021] Figure 1 is a schematic structural diagram of the subgrade structure with an immersed subgrade drainage system in an embodiment of the present invention;

[0022] Figure 2 is a schematic layout diagram of the electrode and the perforated inclined pipe in an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the opening of the small perforated pipe in an embodiment of the present invention.

[0024] In the figure: The distances or sizes between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration.

[0025] Wherein: 1-1. U-shaped infiltration ditch, 1-2. graded crushed stone layer, 1-3. perforated inclined pipe, 1-4. perforated pipeline, 1-5. anode, 1-6. cathode, 1-7. DC power supply, 1-8. sand cushion layer, 1-9. concrete slope protection impermeable layer, 1-10. road surface structure, 1-11. HDPE pipeline, 1-12. bentonite layer, 1-13. detection system, 1-14. humidity sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0027] Embodiment 1

[0028] In a typical embodiment of the present invention, refer to Figures 1 - 3 As shown, there is a subgrade structure with a submerged subgrade drainage system. The submerged subgrade drainage system is provided inside the subgrade structure, and it includes a U-shaped drainage ditch 1-1 and a perforated inclined pipe 1-3. The U-shaped drainage ditch 1-1 includes a vertical drainage ditch with its top extending to the top of the subgrade and a horizontal drainage ditch connected to the bottom end of the vertical drainage ditch. A perforated pipe 1-4 is arranged along the length direction in the middle of the horizontal drainage ditch. One end of several perforated inclined pipes 1-3 is connected to both sides of the perforated pipe 1-4, and the other end of the perforated inclined pipe 1-3 extends to the outside of the slope and a duckbill valve is set; It also includes an electroosmosis system, and the electroosmosis system is arranged inside the slope outside the vertical drainage ditch.

[0029] As Figure 1 shown, the inside of the subgrade is mainly filled with subgrade soil to play the role of supporting the subgrade. A sand and gravel cushion 1-8 is provided at the bottom of the subgrade. The sand and gravel cushion 1-8 provides a channel for the drainage of the subgrade, so that the moisture inside the subgrade can quickly drain downward out of the subgrade.

[0030] As Figure 1 shown, the submerged subgrade drainage system is arranged inside the subgrade structure. The U-shaped drainage ditch 1-1 is arranged at the middle position in the length direction of the subgrade and is symmetrically arranged. The U-shaped drainage ditch 1-1 includes two groups of vertical drainage ditches connected to each other and a group of horizontal drainage ditches, jointly forming the structure of the U-shaped drainage ditch 1-1.

[0031] As Figure 1 shown, the vertical drainage ditch is arranged near the positions of both road shoulders. The top of the vertical drainage ditch extends to the top position of the subgrade, flush with the top of the subgrade, and a permeable sealing layer is set to prevent the water on the top of the subgrade from permeating downward through the top of the vertical drainage ditch.

[0032] The inside of the vertical drainage ditch is filled with pervious filler, and the inside of the horizontal drainage ditch is filled with a graded gravel layer 1-2. The perviousness of the pervious filler is better than that of the graded gravel layer 1-2, so that the water inside the subgrade structure can quickly permeate downward through the pervious filler; the perviousness of the graded gravel layer 1-2 is better than that of the subgrade soil.

[0033] The graded gravel layer 1-2 has good supporting performance. The width of the graded gravel layer 1-2 is adapted to the width of the subgrade top surface, so that it can not only improve the bearing capacity of the subgrade, but also improve the drainage performance.

[0034] The horizontal drainage ditch is arranged along the length direction of the subgrade, located directly below the subgrade top surface and having a certain thickness, so that on the one hand, it ensures the bearing capacity of the subgrade, and on the other hand, when the water inside the subgrade reaches the position of the horizontal drainage ditch, the setting of the graded gravel layer 1-2 can accelerate the drainage speed, so that the moisture can be quickly drained through the drainage pipe structure.

[0035] The cross-sectional width of the horizontal French drain is greater than that of the vertical French drain, aiming to quickly discharge the water in the subgrade when it reaches the position of the horizontal French drain.

[0036] As Figure 1 shown, the perforated pipe 1-4 is arranged near the middle top position of the horizontal French drain. The perforated pipe 1-4 is arranged along the length direction of the subgrade, and both sides are connected to one end of a number of perforated inclined pipes 1-3. The other end of the perforated inclined pipe 1-3 extends to the outside of the slope and is provided with a duckbill valve.

[0037] The setting of the duckbill valve enables the water in the perforated inclined pipe 1-3 to be discharged unidirectionally to the outside of the subgrade slope, while the water outside the subgrade slope cannot enter the perforated inclined pipe inside the subgrade through the duckbill valve.

[0038] To protect the duckbill valve, the duckbill valve at the end of the perforated inclined pipe 1-3 is provided with an HDPE pipe 1-11, and its main function is to reduce the harm of external ultraviolet rays to the duckbill valve.

[0039] As Figure 1 shown, the end of the perforated inclined pipe 1-3 is arranged near the bottom of the slope, and the other end extends to the perforated pipe 1-4 at the middle top position of the horizontal French drain. Therefore, the top part of the perforated inclined pipe 1-3 is located in the horizontal French drain, and the water at different positions in the horizontal French drain can enter the perforated inclined pipe 1-3 or the perforated pipe 1-4. Since the perforated pipe is connected to the perforated inclined pipe 1-3, most of the water is finally discharged through the perforated inclined pipe 1-3.

[0040] As Figure 3 shown, the perforated inclined pipe 1-3 is evenly distributed with small holes, which can enable the water in the subgrade to enter. The structure of the perforated pipe is similar to that of the perforated inclined pipe 1-3, and small holes are also arranged on the pipe wall, but the diameter is larger than that of the perforated inclined pipe 1-3. At the same time, a number of large holes are arranged along the length direction on the perforated pipe 1-4, and the inner diameter of the large holes is adapted to the outer diameter of the perforated inclined pipe 1-3, so as to facilitate the connection between the perforated inclined pipe 1-3 and the perforated pipe 1-4, and enable the water collected in the perforated pipe 1-4 to be diverted into different perforated inclined pipes 1-3.

[0041] In a preferred example, a number of perforated pipes 1-4 are arranged in parallel along the width direction of the subgrade in the horizontal French drain. The middle one is the highest and gradually decreases towards both sides, so that the number of perforated pipes 1-4 is arranged in an inverted V shape. The middle perforated pipe 1-4 is connected to the pipe end of the perforated inclined pipe 1-3, and the other perforated pipes 1-4 are connected to the pipe wall of the perforated inclined pipe 1-3 located in the horizontal French drain. Connecting openings should be correspondingly opened on the perforated inclined pipe 1-3, so that most of the water in the horizontal French drain can enter the perforated pipe 1-4 and then be discharged by the perforated inclined pipe 1-3.

[0042] It is understandable that a layer of one-way drainage geotextile is coated on the perforated inclined pipe 1-3 to prevent sediment from blocking the small holes and affecting drainage. The material of the perforated inclined pipe 1-3 is pvc, with a diameter of 10-15 cm. The pipe diameter of the perforated pipe 1-4 is slightly larger than that of the perforated inclined pipe 1-3.

[0043] In order to further improve the drainage performance of the waterlogged subgrade drainage system, an electroosmosis system is also set up in this embodiment, as Figure 1 shown. The electroosmosis system includes multiple groups of electrodes. Each group of electrodes includes an anode 1-5 and a cathode 1-6. The cathode 1-6 is arranged below the anode 1-5 and close to the upper part of the perforated inclined pipe 1-3. Each group of perforated inclined pipes 1-4 is arranged corresponding to each group of electrodes.

[0044] As Figure 2 shown, the anode 1-5 and the cathode 1-6 of each group of electrodes and the perforated inclined pipe 1-3 are arranged in sequence from top to bottom. It also includes a humidity sensor 1-14, which is arranged inside the slope of the subgrade. The humidity sensor 1-14 and the electrodes are both connected to an external DC power supply 1-7 and form a detection system 1-13. The detection system 1-13 is configured with a controller. The controller can obtain the detected humidity of the humidity sensor 1-14 and compare it with the target humidity, so as to enable the detection system 1-13 to judge whether to turn on the DC power supply 1-7 for electroosmosis drainage according to the detection data of the humidity sensor 1-14. The DC power supply 1-7 is powered by a solar power generation device.

[0045] As Figure 1 shown, both the anode 1-5 and the cathode 1-6 use waste steel bars as electrode materials. In this embodiment, the anode 1-5 and the cathode 1-6 are arranged horizontally, and the cathode 1-6 is arranged directly above the perforated inclined pipe 1-3. After the electroosmosis system is turned on, the moisture at the slope can reach around the cathode 1-6 from around the anode 1-5 and finally enter the perforated inclined pipe 1-3 and be discharged.

[0046] In other examples, the anode 1-5 and the cathode 1-6 are also inclined, with the same slope as that of the perforated inclined pipe 1-3, and the three are arranged in parallel.

[0047] The humidity sensor 1-14 in this embodiment can monitor the moisture content inside the subgrade and control the electroosmosis drainage according to the size of the moisture content. The combined use of electroosmosis drainage and drainage pipes can enable the moisture to be quickly discharged through the inclined drain pipes.

[0048] In order to prevent external water from entering the subgrade, waterproof treatment should be carried out on the subgrade structure. The slope of the subgrade adopts a concrete slope protection, and a waterproof coiled material is laid outside to form a concrete slope protection anti-seepage layer 1-9, which can greatly reduce the infiltration of roadside ponding.

[0049] A layer of bentonite is laid on the upper layer of the roadbed as the bentonite layer 1-12. After the bentonite absorbs water and swells, it forms a waterproof layer, which can effectively prevent water from entering the roadbed. At the same time, a layer of geotextile is laid under the bentonite to reduce the mixing of bentonite and roadbed soil and affect the performance of the roadbed soil. Above the bentonite layer 1-12 is the road surface structure 1-10.

[0050] In this embodiment, the U-shaped drainage ditch 1-1, the perforated inclined pipe 1-3, the perforated pipe 1-4, and the electroosmosis system together form a water interception and drainage channel. Part of the water entering the roadbed body seeps downward through the vertical drainage ditch into the perforated inclined pipe, or enters the horizontal drainage ditch, and seeps into the perforated pipe 1-4 or the perforated inclined pipe 1-3 through the graded gravel layer 1-2. Part of the water is discharged into the perforated inclined pipe 1-3 through electroosmosis and finally discharged through the duckbill valve.

[0051] The duckbill valve at the outlet of the one-way drainage channel can discharge water when there is water flowing out inside. When there is water accumulation on the roadside, it can prevent water from flowing back into the roadbed. The electroosmosis system in this embodiment can accelerate the seepage speed of water in the soil and fix the seepage direction. Its DC power supply is mainly powered by solar energy, which can greatly reduce the consumption of electric energy.

[0052] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A subgrade structure with a drainage system for waterlogged subgrade, characterized in that, An immersion subgrade drainage system is provided inside the subgrade structure, which includes a U-shaped drainage ditch and a perforated inclined pipe. The U-shaped drainage ditch includes a vertical drainage ditch with its top extending to the top of the subgrade and a horizontal drainage ditch connected to the bottom end of the vertical drainage ditch. A perforated pipe is provided in the middle of the horizontal drainage ditch along the length direction. One ends of a number of perforated inclined pipes are connected to both sides of the perforated pipe. The other ends of the perforated inclined pipes extend to the outside of the slope and a duckbill valve is provided; An electroosmosis system is also included, and the electroosmosis system is arranged inside the slope outside the vertical drainage ditch.

2. The subgrade structure with a submerged subgrade drainage system according to claim 1, characterized in that, The vertical drainage ditch is arranged near the positions of the shoulders on both sides of the road. The top of the vertical drainage ditch is a permeation sealing layer, and the inside is filled with pervious fill.

3. The roadbed structure with a waterlogging roadbed drainage system according to claim 2, characterized in that, The inside of the horizontal drainage ditch is filled with a graded crushed stone layer, and the cross-sectional width of the horizontal drainage ditch is greater than the cross-sectional width of the vertical drainage ditch.

4. A roadbed structure with a submerged roadbed drainage system according to claim 1, characterized in that, The perforated pipe is arranged near the top of the horizontal drainage ditch.

5. A subgrade structure with a waterlogging subgrade drainage system according to claim 4, characterized in that, The electroosmosis system includes multiple groups of electrodes. Each group of electrodes includes an anode and a cathode. The cathode is arranged below the anode and near the upper part of the perforated inclined pipe. Each group of perforated inclined pipes is arranged corresponding to each group of electrodes.

6. The roadbed structure with a waterlogging roadbed drainage system according to claim 5, characterized in that, A humidity sensor is also included, which is arranged inside the slope of the subgrade. The humidity sensor and the electrodes are both connected to an external DC power supply and form a detection system. The detection system judges whether to turn on the DC power supply for electroosmosis drainage according to the detection data of the humidity sensor.

7. A roadbed structure with a waterlogging roadbed drainage system according to claim 1, characterized in that, The duckbill valve at the end of the perforated inclined pipe is protected by an HDPE pipe; A layer of one-way drainage geotextile is coated on the perforated inclined pipe.

8. A subgrade structure with a waterlogging subgrade drainage system according to claim 7, characterized in that, The slope of the subgrade is protected by a concrete slope protection, and a waterproof coiled material is laid outside.

9. The subgrade structure with a waterlogging subgrade drainage system according to claim 1, characterized in that, The inside of the subgrade is filled with subgrade soil, a layer of bentonite is laid on the upper layer of the subgrade, and a geotextile is laid below the bentonite.

10. The roadbed structure with a waterlogging roadbed drainage system according to claim 1, characterized in that, The bottom of the subgrade is set as a sand and gravel cushion layer.

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