Single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland

Abstract

The present invention relates to the technical field of agricultural soil and water engineering, and is a single-wing double-layer grid buried pipe device for draining unsaturated soil in farmland, which includes a water-impermeable wing part, a permeable grid, and an isolation layer; the structure of the water-impermeable wing part is a flat plate; the structure of the permeable grid is an assembled grid with upper, middle, and lower layers, including ordinary grids in the upper and lower layers and a serrated grid in the middle layer. The end of the permeable grid is horizontally fixedly connected to the water-impermeable wing part, and an isolation layer is laid on the outer side surface of the permeable grid. The other end of the permeable grid is bent and wound into a cylindrical shape and fixedly connected to the inner side surface of the connection part by an adhesive layer. The present invention can effectively slow down the phenomenon of water flow bypassing around the drainage buried pipe, avoid secondary leakage at the bottom of the buried pipe after water enters the buried pipe, and can also keep the cross-sectional shape of the pipeline unchanged, effectively improve work efficiency, and has a reasonable structure, being economical and practical.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural soil and water engineering, and in particular to a buried pipe device for draining unsaturated soil in farmland. Background Art

[0002] Buried pipe drainage is an important measure for salt pressing and salt washing in the process of farmland saline-alkali treatment. This technology uses porous pipes (also known as buried pipes) buried underground to wash the saline-alkali soil layer above the buried pipes with irrigation water and rainwater, not only removing excessive salts in the soil, but also controlling the groundwater level at a certain depth to prevent upward salt return, thereby providing good soil conditions for plant growth; this technology is favored by people for its obvious treatment effect, short treatment cycle, simple later maintenance and management, and has now developed into a relatively mature technical measure for improving saline-alkali land.

[0003] Traditional farmland buried pipe drainage designs are all based on the theory of saturated flow in soil, and the farmland buried pipe drainage systems used in production practice also work under saturated flow conditions. The drainage efficiency of traditional drainage buried pipes in unsaturated soil is not high, because under unsaturated conditions of the soil, the combined action of the atmospheric pressure in the buried pipe and the matrix suction in the soil makes it difficult for soil water to automatically enter the buried pipe, and the water always flows around the buried pipe; only when the soil around the buried pipe reaches saturation can the water enter the buried pipe and be drained away.

[0004] In the current technology, the publicly disclosed Chinese patent: a wall-less buried pipe for draining in unsaturated soil, patent number: ZL2019 2 2470191.9, is a wall-less buried pipe composed of a wire frame and an outer geotextile. The purpose is to reduce the resistance of water entering the buried pipe and use the matrix suction of the geotextile to guide soil water into the buried pipe to achieve a better drainage effect; its external structure is composed of three arched wire frames, and the geotextile is used as a filter layer to separate the soil and the buried pipe drainage space. However, in the actual use process, there are still deficiencies, such as the phenomenon that water flow around the drainage buried pipe cannot be effectively slowed down, and the secondary leakage at the bottom of the buried pipe after water enters the buried pipe cannot be effectively avoided.

[0005] In order to solve the problems such as the phenomenon that the underground drainage buried pipe in farmland is prone to form bypass flow, the bottom is prone to generate secondary leakage, and the working efficiency is reduced, the present invention has made a breakthrough improvement on the basis of the existing technology. Summary of the Invention

[0006] To solve the above technical problems, the object of the present invention is to provide a single-wing double-layer grid drain pipe device for farmland unsaturated soil drainage, which can effectively slow down the phenomenon of water flow around the drainage pipe, avoid secondary leakage at the bottom of the pipe after water enters the pipe, and can also keep the cross-sectional shape of the pipe unchanged, effectively improve work efficiency, and has a reasonable structure, economy and practicability.

[0007] The present invention discloses a single-wing double-layer grid drain pipe device for farmland unsaturated soil drainage, including an impermeable wing part, a permeable grid and an isolation layer;

[0008] The structure of the impermeable wing part is a flat plate;

[0009] The structure of the permeable grid is an assembled grid with upper, middle and lower layers, including ordinary grids in the upper and lower layers and a sawtooth grid in the middle layer. The ordinary grid includes transverse support rods I and longitudinal support rods I. A plurality of the transverse support rods I and longitudinal support rods I are fixedly connected at intervals and crosswise. After connection, holes are formed between the transverse support rods I and longitudinal support rods I; the sawtooth grid includes transverse support rods II and longitudinal support rods II. A plurality of the transverse support rods II and longitudinal support rods II are fixedly connected at intervals and crosswise. After connection, holes are also formed between the transverse support rods II and longitudinal support rods II; the splicing arrangement of the transverse support rods II and longitudinal support rods II makes the cross-sectional shape of the sawtooth grid a zigzag shape; the sawtooth grid is fixedly connected to the ordinary grids in the upper and lower layers;

[0010] The end of the permeable grid is horizontally fixedly connected to the impermeable wing part. An isolation layer is laid on the outer side of the permeable grid. An adhesive layer is provided on the inner side of the connection part between the permeable grid and the impermeable wing part. The other end of the permeable grid is bent and wound into a cylindrical shape and fixedly connected to the inner side of the connection part by using the adhesive layer.

[0011] Preferably, the length of the impermeable wing part is related to the pipe diameter of the cylindrical permeable grid, and its length is half of the pipe diameter of the cylindrical permeable grid.

[0012] Preferably, the longitudinal support rod II of the sawtooth grid includes an oblique angle support rod with a triangular cross-section.

[0013] Preferably, the shape of the holes formed between the transverse support rod I and the longitudinal support rod I is square, circular, diamond-shaped or triangular; the shape of the holes formed between the transverse support rod II and the longitudinal support rod II is square, circular, diamond-shaped or triangular.

[0014] Preferably, the permeable grid is made of PVC material, and the isolation layer is a geotextile.

[0015] The structure of the present invention includes a permeable grid, an isolation layer, and an impermeable wing part. The structure of the permeable grid is composed of two layers of ordinary grids made of PVC material and a middle layer of sawtooth grid made of PVC material stacked and combined. The cross-sectional shape of the sawtooth grid is a broken line shape, forming a series of triangular support structures. The entire permeable grid is bent and wound into a cylindrical shape, and the connection parts are connected and fixed using an adhesive layer. The outer interface of the pipe is wrapped with geotextile (non-woven fabric), and the geotextile is used as an isolation layer and a filter layer between the pipe and the soil, increasing the porosity of the pipe wall and avoiding pore blockage. The permeable grid is composed of three layers of grids stacked and combined. The middle layer utilizes the compressive characteristics of the triangular structure to well maintain the cross-sectional shape of the pipe, and thus can well support the geotextile without collapse. The present invention refers to this kind of buried pipe structure as a single-wing buried pipe structure.

[0016] The ordinary grid and the middle layer sawtooth grid are made of hard PVC material, which can form large mesh holes, and the mesh hole shapes are rectangular, circular, triangular, or rhombic. The middle layer sawtooth grid has strong compressive ability. The ordinary grid and the middle layer sawtooth grid can be made by the factory at one time. The opening rate of the grid is about 90%, and the size of the outer wrapped geotextile (non-woven fabric) matches the length and outer diameter circumference of the buried pipe.

[0017] The working principle of the present invention:

[0018] The pipe wall of the traditional farmland underground drainage buried pipe only plays the role of supporting the soil pressure and ensuring that the drainage space inside the pipe does not decrease. The present invention adopts a composite layer cylindrical structure composed of two layers of ordinary grids and a middle layer sawtooth grid to support the soil pressure outside the pipe, uses geotextile (non-woven fabric) as an isolation layer and a filter layer to isolate the drainage space of the pipe from the soil, which can not only prevent the soil from entering the pipe, but also improve the compressive ability of the pipe and maintain the shape of the cylindrical pipe. Since the geotextile has good permeability, it can ensure that water enters the pipe. Thus, the present invention maximally eliminates the resistance of soil moisture entering the buried pipe.

[0019] At the same time, in order to more effectively slow down the phenomenon of water flow around the drainage buried pipe and avoid secondary leakage of water at the bottom of the buried pipe after water enters the buried pipe, based on the wall-less drainage buried pipe supported by the grid, the present invention improves the structure of the buried pipe wall. At the same time, an impermeable wing-shaped structure is arranged at the bottom of the buried pipe to form a single-wing type buried pipe. In addition to the advantages of large wall opening rate, good stability, and being able to well support the geotextile in the existing wall-less buried pipe technology, the single-wing buried pipe uses the wing-shaped structure, that is, the impermeable wing part, to intercept the flow around. When the flow direction of the matrix flow changes, the flow velocity will decrease, and then local water accumulation will be formed and promote the drainage of the buried pipe. The impermeable wing part prevents the secondary leakage of the water in the buried pipe.

[0020] Such as Figure 6 、 Figure 7Shown are the soil moisture content distribution diagrams along the soil layer depth and the bar charts of the drainage volume of the blind pipes under the same irrigation conditions (7 liters) for the single-wing blind pipe (with an opening rate of 85% and an outer pipe diameter of 5.5 cm) and the traditional blind pipe (with an opening rate of 85% and an outer pipe diameter of 5.5 cm) of the present invention; among them, the wing length of the single-wing blind pipe is 3.5 cm, and the specifications of the single-layer non-woven fabric wrapped on the outer interfaces of both blind pipes are 300 g / ㎡. The experiment shows that the mass moisture content of the soil around the single-wing blind pipe of the present invention is greater than that of the soil around the circular traditional blind pipe, indicating that the single-wing blind pipe of the present invention has the effect of increasing the resistance to water bypass flow and generating more accumulated water; under the same limited irrigation volume, the traditional blind pipe will have a non-drainage phenomenon, and the soil moisture content at the lower part of the traditional blind pipe in the experiment is greater than that at the lower part of the single-wing blind pipe, indicating that the traditional blind pipe has secondary leakage, while the blind pipe of the present invention can effectively prevent secondary leakage; finally, the drainage volume of the single-wing blind pipe of the present invention is much larger than that of the traditional blind pipe with a circular cross-section.

[0021] Compared with the drainage blind pipes applied in current production, the characteristics of the present invention are that the opening rate is increased, and the resistance of water flowing into the blind pipe is greatly reduced; the present invention is supported by three-layer grids, with stable structure and not easy to deform the pipe cross-section.

[0022] The present invention provides a composite layer cylindrical structure composed of two layers of ordinary grids and an intermediate layer of serrated grids; this structure utilizes the natural compressive capacity of the triangular grids in the intermediate layer and the characteristics of the large porosity of the grids, so that the blind pipe has the advantages of large wall opening rate, good stability, being able to well support the geotextile, and at the same time being able to well maintain the shape of the pipe cross-section, and can effectively slow down the water bypass flow phenomenon around the drainage blind pipe, avoiding secondary leakage at the bottom of the blind pipe after water enters the blind pipe, and is a single-wing double-layer grid blind pipe device for farmland unsaturated soil drainage with reasonable structure, economic and practical. Developing low-cost and high-efficiency integrated infiltration drain pipes and forming composite pipes convenient for mechanized construction have important application value and broad popularization and application prospects for improving the construction efficiency of blind pipe projects, improving the drainage effect and service life of blind pipes. Brief Description of the Drawings

[0023] Figure 1 It is the schematic front view of the cross-section of Embodiment 1 of the present invention.

[0024] Figure 2 is Figure 1 the schematic front view of the expanded state in

[0025] Figure 3 is Figure 1 the schematic three-dimensional structure of the connection relationship between the upper-layer ordinary grid in

[0026] Figure 4 is Figure 1Schematic three-dimensional structure diagram of the connection relationship between the lower ordinary grid in [X] and the impermeable wing part.

[0027] Figure 5 is Figure 1 Schematic three-dimensional structure diagram of the connection relationship between the middle serrated grid in [X] and the impermeable wing part.

[0028] Figure 6 、 7 Respectively are the soil moisture content distribution diagram along the soil layer depth and the bar chart of the drainage volume of the blind pipe of the present invention's single-wing blind pipe (with an opening rate of 85% and an outer diameter of the pipe of 5.5 cm) and the traditional blind pipe (with an opening rate of 85% and an outer diameter of the pipe of 5.5 cm) under the same irrigation condition (7 liters); among them, the wing length of the single-wing blind pipe is 3.5 cm, and the specifications of the single-layer non-woven fabric wrapped on the outer interfaces of the two kinds of blind pipes are both 300 g / ㎡. The experiment shows that the mass moisture content of the soil around the single-wing blind pipe of the present invention is greater than that of the soil around the circular traditional blind pipe, indicating that the single-wing blind pipe of the present invention has the effect of increasing the resistance to water bypass and generating more accumulated water; under the same limited irrigation volume, the traditional blind pipe will have the phenomenon of non-drainage, and the soil moisture content at the lower part of the traditional blind pipe in the experiment is greater than that of the lower part of the single-wing blind pipe, indicating that the traditional blind pipe has secondary leakage, while the blind pipe of the present invention can effectively prevent secondary leakage; finally, the drainage volume of the single-wing blind pipe of the present invention is much larger than that of the traditional blind pipe with a circular cross-section.

[0029] Under the same irrigation volume and external environment, as shown in the figure: 1 is the impermeable wing part, 2 is the adhesive layer, 3 is the permeable grid, 4 is the isolation layer, 5 is the ordinary grid, 6 is the serrated grid, 7 is the transverse support rod I, 8 is the longitudinal support rod I, 9 is the hole, 10 is the transverse support rod II, 11 is the longitudinal support rod II, and 12 is the diagonal support rod. Specific implementation mode

[0030] Example 1:

[0031] Referring to Figures 1 - 7 , which is the schematic structure diagram of the embodiment of the present invention, a single-wing double-layer grid blind pipe device for draining unsaturated soil in farmland, including an impermeable wing part 1, a permeable grid 3, and an isolation layer 4;

[0032] The structure of the impermeable wing part 1 is a flat plate; the structure of the permeable grid 3 is an assembled grid with upper, middle and lower layers, including the ordinary grids 5 in the upper and lower layers and the serrated grid 6 in the middle layer. The ordinary grid 5 includes transverse support rods I 7 and longitudinal support rods I 8. A plurality of the transverse support rods I 7 and longitudinal support rods I 8 are fixedly connected at intervals and crosswise. After connection, holes 9 are formed between the transverse support rods I 7 and longitudinal support rods I 8; the serrated grid 6 includes transverse support rods II 10 and longitudinal support rods II 11. A plurality of the transverse support rods II 10 and longitudinal support rods II 11 are fixedly connected at intervals and crosswise. After connection, holes 9 are also formed between the transverse support rods II 10 and longitudinal support rods II 11; the splicing arrangement of the transverse support rods II 10 and longitudinal support rods II 11 makes the cross-sectional shape of the serrated grid 6 a broken line shape; the serrated grid 6 is fixedly connected to the ordinary grids 5 in the upper and lower layers;

[0033] The end of the permeable grid 3 is horizontally and fixedly connected to the impermeable wing part 1. An isolation layer 4 is laid on the outer side surface of the permeable grid 3. An adhesive layer 2 is provided on the inner side surface of the connection part 13 between the permeable grid 3 and the impermeable wing part 1. The other end of the permeable grid 3 is bent and wound into a tube shape and is fixedly connected to the inner side surface of the connection part 13 by using the adhesive layer 2.

[0034] The length of the impermeable wing part 1 is related to the pipe diameter of the tubular permeable grid 3, and its length is half of the pipe diameter of the tubular permeable grid 3. The longitudinal support rod II 11 of the serrated grid 6 includes an inclined angle support rod 12 with a triangular cross-section.

[0035] The shape of the holes 9 formed between the transverse support rod I 7 and the longitudinal support rod I 8 is square; the shape of the holes 9 formed between the transverse support rod II 10 and the longitudinal support rod II 11 is square.

[0036] The permeable grid is made of PVC material, and the isolation layer is a geotextile.

[0037] Refer to Figure 6 、 Figure 7 As shown: the soil moisture content distribution diagram along the soil layer depth and the bar chart of the drainage volume of the blind pipe of the present invention (opening rate 85%, pipe outer diameter 5.5 cm) and the traditional blind pipe (opening rate 85%, pipe outer diameter 5.5 cm) under the same irrigation conditions (7 liters). The experiment shows that under the same irrigation amount and external environment, the moisture content of the soil around the single-wing blind pipe of the present invention is greater than the mass moisture content of the soil around the traditional blind pipe with a circular cross-section, indicating that the single-wing blind pipe of the present invention has the effect of increasing the resistance to water flow around and generating more accumulated water; Figure 7As shown, in unsaturated soil, under the same and limited irrigation volume, the traditional blind pipe will experience non-drainage; however, the mass water content of the soil at the lower part of the traditional blind pipe with a circular cross-section is higher than that of the soil at the lower part of the single-wing blind pipe, indicating that the single-wing blind pipe can effectively prevent secondary leakage; under a larger irrigation volume, the drainage volume of the single-wing blind pipe of the present invention is also much larger than that of the traditional blind pipe with a circular cross-section.

[0038] Example 2:

[0039] Compared with Example 1, the difference in this example is that: the shape of the hole 9 formed between the transverse support rod I 7 and the longitudinal support rod I 8 is circular; the shape of the hole 9 formed between the transverse support rod II 10 and the longitudinal support rod II 11 is circular.

[0040] Example 3:

[0041] Compared with Example 1, the difference in this example is that: the shape of the hole 9 formed between the transverse support rod I 7 and the longitudinal support rod I 8 is triangular; the shape of the hole 9 formed between the transverse support rod II 10 and the longitudinal support rod II 11 is triangular.

Claims

1. A single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland, characterized in that It includes an impermeable wing part, a permeable grid frame, and an isolation layer; The structure of the impermeable wing part is a flat plate; The structure of the permeable grid frame is an assembled grid frame with upper, middle, and lower layers, including ordinary grid frames in the upper and lower layers and a serrated grid frame in the middle layer. The ordinary grid frame includes transverse support rods I and longitudinal support rods I. A plurality of the transverse support rods I and longitudinal support rods I are fixedly connected at intervals and crosswise. After connection, holes are formed between the transverse support rods I and longitudinal support rods I; the serrated grid frame includes transverse support rods II and longitudinal support rods II. A plurality of the transverse support rods II and longitudinal support rods II are fixedly connected at intervals and crosswise. After connection, holes are also formed between the transverse support rods II and longitudinal support rods II; the splicing arrangement of the transverse support rods II and longitudinal support rods II makes the cross-sectional shape of the serrated grid frame be a broken line shape; the serrated grid frame is fixedly connected to the ordinary grid frames in the upper and lower layers; The end of the permeable grid frame is horizontally fixedly connected to the impermeable wing part. An isolation layer is laid on the outer side surface of the permeable grid frame. An adhesive layer is provided on the inner side surface of the connection part between the permeable grid frame and the impermeable wing part. The other end of the permeable grid frame is bent and wound into a tubular shape and is fixedly connected to the inner side surface of the connection part by using the adhesive layer.

2. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 1, characterized in that The length of the impermeable wing part is related to the diameter of the tubular permeable grid frame, and its length is half of the diameter of the tubular permeable grid frame.

3. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 1 or 2, characterized in that The longitudinal support rod II of the serrated grid frame includes an angled support rod with a triangular cross-section.

4. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 1 or 2, characterized in that The shape of the holes formed between the transverse support rod I and the longitudinal support rod I is square, circular, diamond-shaped, or triangular; the shape of the holes formed between the transverse support rod II and the longitudinal support rod II is square, circular, diamond-shaped, or triangular.

5. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 3, characterized in that The shape of the holes formed between the transverse support rod I and the longitudinal support rod I is square, circular, diamond-shaped, or triangular; the shape of the holes formed between the transverse support rod II and the longitudinal support rod II is square, circular, diamond-shaped, or triangular.

6. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 1 or 2, characterized in that The permeable grid frame is made of PVC material, and the isolation layer is a geotextile.

7. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 3, characterized in that The permeable grid frame is made of PVC material, and the isolation layer is a geotextile.

8. The single-wing double-layer grid buried pipe device for unsaturated soil drainage in farmland according to claim 5, characterized in that The permeable grid frame is made of PVC material, and the isolation layer is a geotextile.

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