Linear drainage ditch for rural areas and method for testing permeation thereof

Abstract

The application discloses a linear drainage ditch for rural areas and a permeation testing method thereof, relates to the technical field of sewage collection, and solves the problems of high use cost and easy damage of the existing concrete drainage ditch for rural areas, reduces the material consumption, and reduces the construction difficulty, and the specific scheme is as follows: the drainage ditch main body is provided with a grid on the groove, the drainage ditch main body is made of a mixed material, the main agent of the mixed material is epoxy resin, the curing agent is modified amine T31 synthesized by phenol, formaldehyde and fatty amine, the diluent is acetone, the toughening agent is dibutyl phthalate, the filler is fly ash, and the aggregate is fine aggregate produced by using construction waste.

Description

Technical Field

[0001] This invention relates to the field of wastewater collection technology, and in particular to a linear drainage ditch for rural use and its permeability testing method. Background Technology

[0002] Rural areas face difficulties in sewage collection due to factors such as lack of scientific planning, unreasonable layout, incomplete or nonexistent drainage pipe networks, complex terrain, low population density, low vertical space utilization, narrow roads, and inadequate infrastructure.

[0003] The inventors discovered that the compressive strength of conventional C25 concrete drainage ditches is around 30 MPa, which is insufficient to withstand conditions such as livestock trampling, tractor crushing, and terrain changes. Furthermore, due to the unstable water quality and large diurnal variations in water volume in rural areas, sewage discharge is intermittent, resulting in low utilization rates of rural sewage pipe networks. Conventional C25 concrete drainage ditches also have poor flowability. To adapt to intermittent sewage discharge, it is necessary to ensure that the concrete drainage ditches have sufficient cross-sectional area, which leads to high operating costs and significant construction difficulties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a linear drainage ditch for rural areas and a method for testing its permeability. The drainage ditch is constructed using an epoxy resin concrete mixture, which solves the problems of high cost and easy damage associated with existing concrete drainage ditches in rural areas.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a linear drainage ditch for rural use, comprising a drainage ditch body, a grid installed on the ditch of the drainage ditch body, the drainage ditch body being made of a composite material, wherein the main component of the composite material is epoxy resin, the curing agent is a modified amine T31 synthesized from phenol, formaldehyde, and fatty amines, the diluent is acetone, the toughening agent is dibutyl phthalate, the filler is fly ash, and the aggregate is fine aggregate produced from construction waste.

[0007] As a further implementation, the epoxy resin is E-44 type epoxy resin.

[0008] As a further implementation, the ratio of aggregate, fly ash and epoxy resin is 8:1:1.

[0009] As a further implementation, the grille is made of stainless steel.

[0010] As a further implementation, the particulate components of the fly ash are glass microspheres, spongy glass, and carbon particles.

[0011] As a further implementation, the trench has a U-shaped cross-section.

[0012] Secondly, the present invention provides a method for permeability testing of linear drainage ditches used in rural areas, as detailed below:

[0013] Drainage ditch specimens were prepared using epoxy resin concrete mixture. The height and bottom area of ​​the drainage ditch specimens were measured. Glass glue was sprayed around the perimeter of the drainage ditch specimens.

[0014] The drainage ditch sample was placed inside the permeability measuring device, and the gap between the drainage ditch sample and the permeability measuring device was sealed with glass glue.

[0015] Water is injected into the permeation measuring device. The water permeates through the sample in the drainage ditch and is discharged. When the injected water volume and the discharged water volume reach equilibrium, the stopwatch is started to measure the time, while the discharged water volume is measured and the water temperature is measured at this time.

[0016] Repeat the operation with different drainage ditch samples and record the data;

[0017] Data was processed and the permeability coefficient was calculated.

[0018] As a further implementation, the permeation measuring device consists of a test mold with an opening at the top, a water injection sleeve inserted into the top of the test mold, and a water tank. The test mold is fixedly installed in the water tank through a positioning water groove. The bottom of the inner cavity of the test mold is connected to the positioning water groove. The side wall of the water injection sleeve is provided with a water inlet, and the side wall of the water tank is provided with a water outlet.

[0019] As a further implementation, the positioning water tank is lower than the water outlet, and the water inlet is higher than the water outlet.

[0020] As a further implementation, the cross-sectional dimensions of the mold cavity are the same as those of the drainage ditch sample, and the height of the mold cavity is greater than that of the drainage ditch sample.

[0021] The beneficial effects of the present invention are as follows:

[0022] (1) This invention uses fly ash as a filler for preparing drainage ditches, which can simultaneously improve the mechanical properties, mechanical strength and lubrication properties of the resin concrete. Dibutyl phthalate is used as a toughening agent to improve the toughness of the epoxy resin adhesive after curing, which can effectively improve the bending and impact resistance, so that the prepared drainage ditch can better adapt to the external environment. Using construction waste and fly ash for the process can reduce the cost and have good economic benefits. On the other hand, it can reuse waste and solid waste, which has significant environmental benefits.

[0023] (2) The particulate components of fly ash in this invention can lubricate the aggregates, improve the roughness coefficient of the prepared drainage ditch, and increase its flow capacity. When applied in rural areas, it can better cope with the complex and ever-changing water quality environment in rural areas. Moreover, the increased flow capacity can effectively reduce the cross-section of the drainage ditch, which not only makes it easier to reduce materials and costs, but also reduces the difficulty of construction.

[0024] (3) The epoxy resin used in this invention is E-44 type, which has lower viscosity and better operability, ensuring sufficient fluidity during preparation and easy molding. After curing, the adhesive viscosity is greater, making it more suitable for the preparation of resin concrete. The addition of dibutyl phthalate can improve its bending and impact resistance, allowing the resulting drainage ditch to better adapt to temperature changes in the external environment.

[0025] (4) The test mold of the present invention is connected to the water tank through a positioning water tank, and the positioning water tank is lower than the water outlet, which can play a buffering role and prevent the water that has seeped through the drainage ditch from flowing directly out of the water tank. The water that has seeped out can flow slowly in the water tank and then be discharged, which effectively ensures the accuracy of the water flow rate measurement.

[0026] (5) The height of the water injection sleeve in the permeation measuring device of the present invention is adjustable and the sample replacement is convenient. It can repeat the test on different drainage ditch samples. At the same time, the test parameters (time, water head difference) can be adjusted according to actual needs, which greatly saves test costs and improves test efficiency. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a cross-sectional structural diagram of a linear drainage ditch for rural use according to one or more embodiments of the present invention;

[0029] Figure 2 This is a schematic diagram of the permeation measuring device according to one or more embodiments of the present invention;

[0030] In the diagram: the spacing or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0031] The components include: 1. Grille; 2. Drainage ditch body; 3. Water injection sleeve; 4. Trial mold; 5. Drainage ditch sample; 6. Water tank; 7. Water outlet; and 8. Positioning water tank. Detailed Implementation

[0032] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] As described in the background section, the compressive strength of conventional C25 concrete drainage ditches is around 30 MPa, which is insufficient to withstand conditions such as livestock trampling, tractor crushing, and terrain changes. Furthermore, due to unstable water quality and significant diurnal variations in water volume in rural areas, sewage discharge is intermittent, resulting in low utilization rates of rural sewage pipe networks. Conventional C25 concrete drainage ditches also exhibit poor flowability. To accommodate intermittent sewage discharge, it is necessary to ensure that the concrete drainage ditches have sufficient cross-sectional area, leading to high operating costs and significant construction difficulties. To address these technical problems, this invention proposes a linear drainage ditch for rural areas and its permeability testing method.

[0034] Example 1

[0035] In a typical embodiment of the present invention, such as Figure 1 As shown, a linear drainage ditch for rural use is proposed, including a grid 1 and a drainage ditch body 2. The cross-section of the ditch inside the drainage ditch body 2 is U-shaped, and the grid 1 is installed on the ditch.

[0036] The grating 1 is made of stainless steel; the main body of the drainage ditch 2 is made of a mixture of materials, wherein the main material is epoxy resin, the curing agent is a modified amine T31 synthesized from phenol, formaldehyde and fatty amine, the diluent is acetone, the toughening agent is dibutyl phthalate, the filler is fly ash, and the aggregate is fine aggregate produced from construction waste.

[0037] Adding suitable fillers to resin adhesives can further improve their performance. On the one hand, it can increase mechanical strength and bonding properties; on the other hand, it can adjust viscosity and flowability, and can also reduce costs to some extent. Commonly used fillers for epoxy resins include: quartz sand, glass fiber, calcium carbonate, talc, alumina, silica, corundum, and metal powder. Different fillers will change different properties of epoxy resins. For example, metal powder and corundum fillers can increase hardness, alumina fillers can increase adhesion and mechanical strength, glass fiber fillers can increase toughness, and quartz sand fillers can reduce shrinkage and improve wear resistance and lubrication properties.

[0038] Using fly ash as a filler in the preparation of drainage ditches can simultaneously improve the mechanical properties, mechanical strength, and lubrication properties of the resulting resin concrete. Specifically, the main chemical components of fly ash include calcium oxide, silicon dioxide, aluminum oxide, and some complex double salts. The main particulate components include glass microspheres, spongy glass, and carbon particles. These particulate components can lubricate the aggregates, improve the roughness coefficient of the prepared drainage ditch, and increase its flow capacity. When applied in rural areas, it can better cope with the complex and variable water quality environment, such as domestic sewage, rainwater mixed with mud, and irrigation water. Moreover, the increased flow capacity can effectively reduce the cross-section of the drainage ditch, which not only makes it easier to reduce material usage and lower costs, but also reduces construction difficulty.

[0039] Using dibutyl phthalate as a toughening agent improves the toughness of epoxy resin adhesive after curing, effectively enhancing its bending and impact resistance, allowing the resulting drainage ditch to better adapt to external environments, such as temperature changes.

[0040] Using construction waste and fly ash for processing can reduce costs and have good economic benefits, while also enabling the reuse of solid waste and other resources, resulting in significant environmental benefits.

[0041] Specifically, in the preparation of resin concrete, commonly used organic materials include unsaturated polyester resin, epoxy resin, furan resin, and phenolic resin. Among them, furan resin has poor oxidation resistance, and the mechanical properties of phenolic resin are slightly lower than those of unsaturated polyester resin and epoxy resin. It is also mostly used in high-temperature fields. Epoxy resin not only has better mechanical properties than unsaturated resin, but also has excellent adhesion to various metal and non-metal materials, making it easier to combine with grid 1. Therefore, it is more suitable for the preparation of resin concrete using construction waste as aggregate in this embodiment.

[0042] The commonly used epoxy resins for making resin concrete are E-51 and E-44. E-51 epoxy resin has an average epoxy value of 51 / 100 (0.48-0.54), while E-44 epoxy resin has an average epoxy value of 44 / 100 (0.41-0.47). Compared to E-51, E-44 has lower viscosity, better workability, and ensures sufficient fluidity during preparation, facilitating molding. It also has a higher viscosity after curing, making it more suitable for preparing the resin concrete in this embodiment. However, while E-44 resin has high mechanical strength after curing, it is more brittle, especially at low temperatures, resulting in poor impact resistance. To improve the toughness of the cured epoxy resin adhesive, an appropriate amount of dibutyl phthalate was added as a toughening agent to enhance its flexural and impact resistance.

[0043] General studies have shown that, under the same molding conditions, the shear strength of epoxy resin adhesives increases significantly with the increase of the fly ash mass fraction. Experimental tests have shown that when the fly ash mass fraction is around 150 (i.e., 100 parts resin mixed with 150 parts fly ash), the shear strength of the adhesive reaches a peak of approximately 22 MPa. Thereafter, the shear strength slowly decreases with further increases in mass fraction. This phenomenon is due to the chemical reactivity of silica, alumina, and other components in fly ash. Under the action of an alkaline activator, the fly ash reacts, acting as a reinforcing component within the cementitious material. Furthermore, fly ash contains a large number of glass microspheres. These spherical particles are dispersed throughout the adhesive layer, ensuring uniform stress distribution, increasing the internal hardness of the adhesive layer, stabilizing the shrinkage rate, and reducing curing time.

[0044] By studying the relationship between the mass fraction of fly ash and the shear strength of epoxy resin adhesive, the optimal ratio of fly ash filler can be determined. When the mass fraction of fly ash is 150%, the epoxy resin adhesive and aggregate are mixed in a 2:8 ratio to form resin concrete. After one week of curing, the compressive strength can reach over 60 MPa, and after one month of curing, the compressive strength can reach 80 MPa. This is because the content of silica, alumina, and iron oxide in fly ash accounts for about 90% of the total fly ash content, and most of them are glassy solid or hollow spherical particles with a particle size of 1-5 μm. This greatly improves the wetting ability of the epoxy resin adhesive, lubricates the aggregate, and significantly improves the workability of the resin concrete. This not only makes the concrete denser and more uniform but also makes it easier to construct. At the same time, using fly ash as filler, the fly ash microspheres also help reduce the weight of the concrete and improve its resistance to damage.

[0045] Since most rural areas currently have unpaved surfaces and many roads are dirt tracks with low traffic volume, and large vehicles rarely pass through, the strength requirements for linear drainage ditches are not as high as in cities. Using the aforementioned high-strength resin concrete materials would inevitably lead to waste. Therefore, it is necessary to reduce the amount of epoxy resin adhesive used to lower costs.

[0046] However, the upward trend of shear strength of epoxy resin adhesives is limited. As the amount of filler is too large and the epoxy resin content decreases, the bonding area of ​​the adhesive will decrease, thus causing the shear strength of the adhesive to decrease slowly.

[0047] Therefore, considering factors such as material hardness, strength, adhesive viscosity, and molding and curing speed, the ratio of aggregate, fly ash, and resin selected in this embodiment is 8:1:1.

[0048] The proportion of epoxy resin adhesive in this embodiment is the optimal choice for rural drainage ditch mixtures, which not only reduces costs but also ensures bonding area. In order to further test whether the above proportion of aggregate, fly ash and resin is the optimal choice, three other groups of mixture samples with other proportions were also set up, namely 8.5:0.5:1, 7.5:1.5:1 and 7:2:1.

[0049] The compressive strength, pipe roughness coefficient, and permeability of the aforementioned proportional samples were measured. In the compressive strength and pipe roughness coefficient tests on the drainage ditch, the drainage ditch sample was first placed in the middle of the lower pressure plate of the testing machine, and the upper and lower pressure plates were filled with pads. The supporting surface of the sample was perpendicular to the top surface of the molded product. The continuous and uniform loading speed was controlled at approximately 0.3 MPa / s, and the pressure was applied slowly. When the specimen approached failure and began to deform rapidly, the throttle was stopped and adjusted until the drainage ditch sample failed, and the failure load was recorded. The compressive strength value was calculated using the axial compressive strength formula.

[0050] Formula for axial compressive strength:

[0051]

[0052] In the formula: f c The axial compressive strength is (MPa).

[0053] P: Destructive load (N);

[0054] A: Specimen bearing area (mm²) 2 ).

[0055] The roughness coefficient of the drainage ditch and the overload capacity were calculated according to the "SL155-95 Hydraulic Engineering (Conventional) Model Test Procedure" and the Darcy-Weisbach formula and Manning formula.

[0056] Darcy-Weisbach formula:

[0057]

[0058] Where: h f The head loss along the route is expressed in meters (m).

[0059] λ is the friction head loss coefficient;

[0060] L is the distance between the cross sections, in meters.

[0061] v is the average flow velocity (m / s);

[0062] d is the inner diameter of the pipe (m).

[0063] Manning's formula:

[0064]

[0065] In the formula: C is the Chezy coefficient, (m 0.5 / s); In this embodiment

[0066] n is the roughness coefficient;

[0067] R is the hydraulic radius, and in this experiment, R = d / 4.

[0068] The overload capacity of the drainage ditch is calculated using the following hydraulic formula:

[0069]

[0070]

[0071]

[0072] In the formula: Q is the flow rate (m 3 / s);

[0073] A is the cross-sectional area of ​​the water passage (m²) 3 );

[0074] i represents the ratio decrease.

[0075] The permeability coefficient of the drainage ditch samples was determined using the constant head method, and the data obtained are shown in Table 1.

[0076] Table 1 Comparison of drainage ditch samples with different proportions

[0077]

[0078] Calculations show that when the ratio of aggregate, fly ash, and resin is 8:1:1, the compressive strength is the highest at 47.8 MPa, the permeability coefficient is approximately 2.1, the roughness coefficient is approximately 0.015–0.016 in the turbulent transition zone (v < 1.2 m / s) and approximately 0.014–0.015 in the rough zone (v > 1.2 m / s), and the overload flow rate is approximately 0.8 m³ / s. 3 / s, far exceeding the compressive strength of about 30Mpa of conventional C25 concrete drainage ditches, can better cope with livestock trampling, tractor running and terrain changes when applied in rural areas. In addition, the sample has low permeability, which is more conducive to sewage transportation and has a greater overload capacity.

[0079] Example 2

[0080] In another typical embodiment of the present invention, a permeability testing method for linear drainage ditches used in rural areas is proposed, as follows:

[0081] Epoxy resin concrete mixture was used to prepare drainage ditch sample 5. The surface of drainage ditch sample 5 was wiped dry. The height and bottom area of ​​drainage ditch sample 5 were measured. Glass glue was sprayed around drainage ditch sample 5 to eliminate the gap between drainage ditch sample 5 and permeability measuring device to prevent water from flowing out of the gap.

[0082] Among them, the permeation measuring device, such as Figure 2 As shown, it consists of a water-filled sleeve 3, a test mold 4, and a water tank 6. The test mold 4 is a cubic structure with an open top, used to hold the drainage ditch sample 5. The cross-sectional dimensions of the inner cavity of the test mold 4 are the same as the cross-sectional dimensions of the drainage ditch sample 5, and the height of the inner cavity of the test mold 4 is greater than that of the drainage ditch sample 5.

[0083] The test mold 4 is fixedly installed in the water tank 6 through the positioning water tank 8. The bottom of the inner cavity of the test mold 4 is connected to the positioning water tank 8, so that the water that has permeated through the drainage ditch sample 5 can enter the water tank 6 through the positioning water tank 8. The side wall of the water tank 6 is provided with a water outlet 7 for water discharge. The positioning water tank 8 is mainly used for water buffering. The positioning water tank 8 is lower than the water outlet 7 to prevent the water that has permeated through the drainage ditch sample 5 from flowing directly out of the water tank 6. The permeated water can flow slowly in the water tank 1 and then be discharged, which effectively ensures the accuracy of water flow rate measurement.

[0084] The water injection sleeve 3 has a bottom-open structure and a water inlet on the top side wall. The water injection sleeve 3 is inserted into the top of the test mold 4, and the interior of the water injection sleeve 3 is connected to the inner cavity of the test mold 4. It is mainly used to change the head difference between the water outlet 7 and the water inlet.

[0085] After placing the drainage ditch sample 5 into the mold 4, seal it with glass glue to ensure good sealing between the drainage ditch sample 5 and the side wall of the mold 4, and connect the water inlet.

[0086] Turn on the tap and slowly fill the water from the inlet, so that the water flows from bottom to top and fills the entire water filling sleeve 3. The water seeps through the drainage ditch sample 5 into the positioning water tank 8, and then is discharged from the outlet 7. When the amount of water injected and the amount of water discharged from the outlet 7 reach a balance, start the stopwatch and measure the amount of water discharged from the outlet 7, and measure the water temperature at that time.

[0087] Repeat the above operation for different drainage ditch samples 5 and record the corresponding data;

[0088] Data was processed and the permeability coefficient was calculated.

[0089] The technical formula for the permeability coefficient is as follows:

[0090]

[0091] In the formula: K T The permeability coefficient (cm) at a water temperature of T℃3 / s);

[0092] Q represents the amount of water seeping out within time t seconds (cm³). 3 );

[0093] D represents the thickness (cm) of the new material drainage ditch specimen;

[0094] H represents the head difference (cm);

[0095] Δt is the infiltration time (s);

[0096] A is the cross-sectional area (cm²) of the drainage ditch sample. 2 ).

[0097] In this embodiment, the permeability testing method uses a self-made permeability measuring device, which can perform repeated tests on different drainage ditch samples. The test parameters (time, head difference) can be adjusted according to actual needs, which greatly saves test costs and improves test efficiency.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the permeability of linear drainage ditches used in rural areas, characterized in that, Specifically as follows: The drainage ditch includes a drainage ditch body, on which a grating is installed. The drainage ditch body is made of a mixed material, the main component of which is epoxy resin, the curing agent is a modified amine T31 synthesized from phenol, formaldehyde and fatty amines, the diluent is acetone, the toughening agent is dibutyl phthalate, the filler is fly ash, and the aggregate is fine aggregate produced from construction waste. Drainage ditch specimens were prepared using epoxy resin concrete mixture. The height and bottom area of ​​the drainage ditch specimens were measured. Glass glue was sprayed around the perimeter of the drainage ditch specimens. The drainage ditch sample is placed inside the permeability testing device, and the gap between the drainage ditch sample and the permeability testing device is sealed with glass glue. The permeability testing device consists of a mold with an open top, a water injection sleeve inserted into the top of the mold, and a water tank. The mold is fixedly installed in the water tank through a positioning water groove. The bottom of the inner cavity of the mold is connected to the positioning water groove. The side wall of the water injection sleeve is provided with a water inlet, and the side wall of the water tank is provided with a water outlet. Water is injected into the permeation measuring device. The water permeates through the sample in the drainage ditch and is discharged. When the injected water volume and the discharged water volume reach equilibrium, the stopwatch is started to measure the time, while the discharged water volume is measured and the water temperature is measured at this time. Repeat the operation with different drainage ditch samples and record the data; Data processing and penetration coefficient calculation; The formula for calculating the permeability coefficient is: ； In the formula: Permeability coefficient at water temperature T℃: cm 3 / s; Q is the amount of water seeping out in seconds t: cm 3 D is the thickness of the new material drainage ditch specimen: cm; H is the head difference: cm; Δt is the infiltration time: s; A is the cross-sectional area of ​​the drainage ditch specimen: cm² 2 .

2. The permeability testing method for a linear drainage ditch used in rural areas according to claim 1, characterized in that, The positioning water tank is lower than the water outlet, and the water inlet is higher than the water outlet.

3. The permeability testing method for a linear drainage ditch used in rural areas according to claim 1, characterized in that, The cross-sectional dimensions of the inner cavity of the mold are the same as those of the drainage ditch sample, and the height of the inner cavity of the mold is greater than that of the drainage ditch sample.

4. The permeability testing method for a linear drainage ditch used in rural areas according to claim 1, characterized in that, The epoxy resin is E-44 type epoxy resin.

5. The permeability testing method for a linear drainage ditch used in rural areas according to claim 1, characterized in that, The ratio of aggregate, fly ash and epoxy resin is 8:1:

1.

6. The permeability testing method for a rural linear drainage ditch according to claim 1, characterized in that, The grille is made of stainless steel.

7. The permeability testing method for a rural linear drainage ditch according to claim 1, characterized in that, The particulate components of the fly ash are glass microspheres, spongy glass, and carbon particles.

8. The permeability testing method for a linear drainage ditch used in rural areas according to claim 1, characterized in that, The trench has a U-shaped cross-section.

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