A siphon drainage structure based on an existing road drainage system and a design method thereof

Abstract

The present application relates to the field of road engineering, and more particularly to a siphon drainage structure based on an existing road drainage system and a design method thereof, comprising a water collecting ditch, a side ditch, a plurality of water outlets and a siphon pipe, the siphon pipe is buried under the road, the siphon pipe extends from one side of the road to the other side of the road, the siphon pipe comprises a water storage section, a communication section and a drainage section, the two ends of the water storage section are curved upward, one end of the water storage section is communicated with the water outlet, the other end of the water storage section is connected with the communication section, and the highest point of the communication section is higher than that of the water storage section; the drainage section is connected with the communication section, and the downward inclination angle of the drainage section is greater than that of the communication section, so as to quickly drain the water flowing from the communication section. Through the siphon effect and the structure optimization, the drainage of the road side ditch is accelerated, the water flow speed is significantly improved compared with the traditional straight drainage, and the accumulated water in the side ditch can be drained in a short time.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, and in particular to a siphon drainage structure and its design method based on existing road drainage systems. Background Technology

[0002] Mountain roads are more dangerous than those in plains. The geological structure of mountainous areas is complex, with many fault zones and loose deposits. When encountering disasters such as heavy rainfall and earthquakes, they are prone to sudden geological disasters such as rockfalls, landslides, mudslides, roadbed subsidence and slope instability, which directly threaten the safety of road traffic.

[0003] In recent years, mountain highway collapses and dangerous accidents have occurred frequently. According to investigation and analysis, the causes of such mountain highway collapses are as follows: (1) Mountain road construction will greatly change the natural slope catchment area. If the road drainage system is not well constructed or the road drainage system is partially blocked by soil and rocks, the road surface can become a transient smooth riverbed. A large amount of runoff rainwater from multiple natural catchment areas can be concentrated on the road surface. A large amount of rainwater is diverted along the road to other catchment areas or overflows the roadside and enters the roadbed slope below, making the highway into a river and causing great harm to the safe driving of cars. (2) Under the action of a large amount of runoff, the surface soil of the roadbed slope will be eroded, and then the whole structure will become unstable, forming landslides and collapses, which will cause the roadbed to collapse and form pits. If fast-moving vehicles cannot stop in time, they will rush into the pits, causing major casualties and economic losses. Summary of the Invention

[0004] The main objective of this invention is to provide a siphon drainage structure and its design method based on existing road drainage systems, in order to solve the problems of existing mountain road drainage systems being easily blocked, slow drainage causing rainwater to flood the road surface, and easily leading to roadbed and slope collapse.

[0005] To achieve the above objectives, the present invention provides a siphon drainage structure based on an existing road drainage system, including a drainage ditch, a side ditch, multiple drainage outlets, and a siphon pipe. The drainage ditch is located on the slope and extends downwards from the slope. The side ditch is located on the side of the road near the slope. The drainage ditch is connected to the side ditch. The drainage outlets are evenly distributed along the longitudinal direction of the side ditch at the bottom of the side ditch.

[0006] The siphon pipe is buried under the road and extends from one side of the road ditch to the other side of the road. The siphon pipe includes a water storage section, a connecting section, and a drainage section connected sequentially along its extension direction. The two ends of the water storage section are bent upwards. One end of the water storage section is connected to the drain outlet, and the other end of the water storage section is connected to the connecting section. The highest point of the connecting section is higher than the bottom height of the drain outlet. The drainage section is connected to the connecting section, and the downward tilt angle of the drainage section is greater than the tilt angle of the connecting section, so as to quickly drain the water flowing into the connecting section.

[0007] Furthermore, the height of the connection between the water storage section and the connecting section is higher than the bottom height of the drain outlet, and the connecting section extends downward from the side ditch to the other side of the road.

[0008] Furthermore, the drain outlet is circumferentially concave to form a bowl-shaped depression, the siphon tube is connected to the bottom of the depression, and the diameter of the depression is the same as the width of the side ditch.

[0009] Furthermore, it also includes a drainage ditch, and a stepped platform is provided on the slope. The stepped platform extends along the slope surface and the platform surface is parallel to the road. The drainage ditch is set at the top of the slope and inside the stepped platform, and the drainage ditch is connected to the drainage ditch.

[0010] This invention also provides a design method for a siphon drainage structure based on an existing road drainage system, applicable to the siphon drainage structure based on an existing road drainage system as described above, comprising the following steps:

[0011] S1. Obtain the location of the drainage ditch, and divide the side ditch into multiple segmented side ditches according to the location of the drainage ditch, thereby determining the length of the segmented side ditch located between adjacent drainage ditches.

[0012] S2. Obtain the preset number of drainage outlets in the segment side ditch, determine the layout spacing of the drainage outlets according to the length of the segment side ditch and the preset number of drainage outlets, and determine the layout position of the drainage outlets in the segment side ditch according to the layout spacing of the drainage outlets.

[0013] S3. Obtain the inflow rate of the segmented ditch, and obtain the inflow rate of a single drainage outlet based on the inflow rate and the preset number of drainage outlets, thereby determining the radius of the drainage outlet;

[0014] S4. Determine the siphon tube radius based on the drain outlet radius, obtain the minimum anti-clogging diameter of the siphon tube, and determine whether the siphon tube radius is greater than or equal to the minimum anti-clogging diameter; if yes, proceed to step S5; if no, increase the drain outlet radius by a preset increment and return to step S4.

[0015] S5. Obtain the bending angle of the water storage section of the siphon pipe, determine the siphon enhancement factor based on the bending angle, and determine the maximum drainage flow rate of the drain outlet based on the drain outlet radius and the siphon enhancement factor.

[0016] S6. Determine whether the maximum drainage flow rate is greater than the inflow flow rate of the single drain outlet; if yes, the design is complete; if no, increase the radius of the drain outlet by a preset increment and return to step S4.

[0017] Furthermore, step S2 specifically includes the following steps:

[0018] Obtain the preset distance between the beginning and end of the segmented ditch, and determine the positions of the first and last drainage outlets in the segmented ditch based on the preset distance between the beginning and end; wherein, the preset distance between the beginning and end is the distance from the first drainage outlet to the starting point of the segmented ditch and the distance from the last drainage outlet to the ending point of the segmented ditch;

[0019] Obtain the preset number of drainage outlets in the segmented ditch, and determine the layout spacing of the drainage outlets based on the length of the segmented ditch, the preset distance between the beginning and end, and the preset number of drainage outlets;

[0020] The placement of each drainage outlet within the segmental ditch is determined based on the spacing between the outlets.

[0021] Furthermore, step S3 specifically includes the following steps:

[0022] Obtain the inflow rate of the segmented ditch, and obtain the inflow rate of a single drainage outlet based on the inflow rate and the preset number of drainage outlets;

[0023] Obtain the flow coefficient of the drain outlet, and calculate the radius of the drain outlet based on the inflow rate of the individual drain outlet and the flow coefficient of the drain outlet.

[0024] Obtain the construction accuracy value, and convert the radius calculation value to obtain the drainage outlet radius based on the construction accuracy value.

[0025] Furthermore, step S5 specifically includes the following steps:

[0026] Obtain the bending angle of the water-storing section of the siphon pipe, and determine the siphon enhancement factor based on the bending angle; wherein, the siphon enhancement factor is determined by the bending angle, and the siphon enhancement factor... Ks ∝sin θ θ is the bending angle;

[0027] Obtain the blockage probability model and discharge coefficient of the drain outlet, establish a drain outlet discharge capacity calculation model based on the drain outlet radius, siphon enhancement factor, blockage probability model and discharge coefficient, and determine the maximum drainage flow of the drain outlet through the drain outlet discharge capacity calculation model.

[0028] More preferably, after step S5, the following steps are further included:

[0029] Obtain the duration of the strongest local rainfall, and determine the total drainage volume of the outlet based on the rainfall duration and the maximum drainage flow rate;

[0030] The intensity of the strongest local rainfall and the equivalent catchment area of ​​the drainage outlet are obtained to determine the total rainfall at the drainage outlet;

[0031] A first verification value for the spacing of the drainage outlets is established based on the total drainage volume and total rainfall.

[0032] Obtain the slope and hydraulic radius of the ditch, and determine the flow velocity of the water in the ditch based on the slope and hydraulic radius;

[0033] Obtain the discharge response time of the water flow, and establish a second verification value for the spacing of the discharge outlets based on the flow velocity and the discharge response time;

[0034] By comparing the first verification value and the second verification value to obtain the minimum verification value, it is determined whether the layout spacing of the drain outlets is greater than or equal to the minimum verification value; if not, the layout spacing of the drain outlets is increased so that the layout spacing of the drain outlets is greater than or equal to the minimum verification value.

[0035] More preferably, after step S5, the following steps are further included:

[0036] S61. Obtain the radius of the drainage outlet of each segment of the ditch, and obtain the blockage probability of the drainage outlet in each segment of the ditch according to the blockage probability model.

[0037] S62. Obtain the standard value of the blockage probability, and determine whether the blockage probability of the drainage outlet in each segment of the ditch is less than or equal to the standard value of the blockage probability. If yes, the blockage probability is verified. If no, the radius of the drainage outlet is increased by a preset increment, and the process returns to step S61.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This application upgrades existing road drainage systems by adding drainage outlets and siphon pipes, resulting in a small amount of work, a short construction period, and significantly lower costs compared to building a new road drainage system. The siphon effect and structural optimization synergistically accelerate drainage in roadside ditches: the upward bends at both ends of the siphon pipe's water storage section quickly create a stable water seal, while the high-level placement of the connecting section ensures siphon conditions. Combined with the larger inclination angle of the drainage section, this significantly improves the water flow velocity compared to traditional direct drainage, emptying the ditches quickly and preventing insufficient drainage capacity that could lead to flooding. This is particularly suitable for mountainous areas with concentrated heavy rainfall and short-duration high intensity. The efficient drainage capacity of this application significantly reduces the time rainwater remains in ditches and slopes, thereby greatly reducing rainwater infiltration into the roadbed and slopes, lowering soil pore water pressure, and effectively preventing roadbed softening and slope collapse. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the siphon drainage structure in one embodiment of the present invention;

[0042] Figure 2 This is a top view of a partial structure of the drain outlet of the siphon drainage structure in one embodiment of the present invention;

[0043] Figure 3 This is a schematic flowchart illustrating the design method of a siphon drainage structure according to an embodiment of the present invention.

[0044] Explanation of icon numbers:

[0045] 1. Interception ditch; 2. Slope; 3. Drainage ditch; 4. Road; 5. Side ditch; 6. Drainage outlet; 71. Water storage section; 72. Connecting section; 73. Drainage section; 8. Roadbed; 9. Stepped platform.

[0046] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0050] Please see Figure 1 and Figure 2 This embodiment provides a siphon drainage structure based on an existing road drainage system, including a drainage ditch 3, a side ditch 5, multiple drainage outlets 6, and a siphon pipe. The drainage ditch 3 is set on a slope 2 and extends downward from the slope 2. The side ditch 5 is set on the side of the road 4 near the slope 2. The slope 2 extends longitudinally along the road 4. The drainage ditch 3 is connected to the side ditch 5. The drainage outlets 6 are evenly distributed along the longitudinal direction of the side ditch 5 at the bottom of the side ditch 5.

[0051] The siphon pipe is buried under road 4, extending from one side of road 4 to the other. The siphon pipe includes a water storage section 71, a connecting section 72, and a drainage section 73. Both ends of the water storage section 71 curve upwards. One end of the water storage section 71 connects to the drainage outlet 6, and the other end connects to the connecting section 72. The highest point of the connecting section 72 is higher than the bottom of the drainage outlet. The drainage section 73 connects to the connecting section 72, and its downward inclination angle is greater than that of the connecting section 72, allowing for rapid drainage of water flowing into the connecting section 72. In this embodiment, the drainage section 73 connects to a drainage ditch located under the roadbed 8 on the other side of road 4, preventing floodwater from directly impacting the roadbed 8 soil after exiting the siphon pipe, thus preventing softening and erosion of the roadbed 8 and reducing the risk of roadbed 8 collapse.

[0052] This embodiment is based on the renovation of the existing road drainage system. The upgrade can be completed by adding a drain outlet 6 and a siphon pipe. The renovation work is small and the construction period is short, which significantly reduces the cost compared to building a new road drainage system. It is especially suitable for the quality improvement and renovation of existing roads in mountainous areas. The drainage of the roadside ditch 5 is synergistically accelerated by the siphon effect and structural optimization: the upward bend design at both ends of the water storage section 71 of the siphon pipe can quickly form a stable water seal, and the high position setting of the connecting section 72 prevents air infiltration from destroying the siphon conditions. Combined with the structural design of the drainage section 73 with a larger inclination angle, the water flow speed is significantly improved compared with the traditional direct drainage effect. It can empty the water in the ditch 5 in a short time and avoid the phenomenon of insufficient drainage capacity causing water to flood the road surface. It is especially suitable for the scenario of concentrated rainstorms and short-term heavy rainfall in mountainous areas. The efficient drainage capacity of this embodiment greatly shortens the residence time of rainwater in the ditch 5 and the slope 2, thereby greatly reducing the amount of rainwater infiltration into the roadbed 8 and the slope 2, reducing the pore water pressure of the soil, and effectively preventing the softening of the roadbed 8 and the collapse of the slope 2.

[0053] In this embodiment, the drainage outlets 6 are evenly distributed at the bottom along the longitudinal direction of the side ditch 5. Combined with the interconnected layout of the water collection ditch 3 and the side ditch 5, a seamless connection of "slope water collection - side ditch water collection - drainage outlet water guidance" is achieved, avoiding local water accumulation and stagnation in the side ditch 5.

[0054] In this embodiment, the curved structure of the water storage section 71 during heavy rain can form a continuous water flow to flush away sediment and reduce the deposition of silt in the pipe. It can also remove debris accumulation in the siphon pipe. The large-angle design of the drainage section 73 further enhances the shear force of the water flow and reduces the probability of debris adhesion, thus reducing the frequency of clogging compared to traditional direct-buried drainage pipes.

[0055] As a further embodiment, the height of the connection between the water storage section 71 and the connecting section 72 is higher than the bottom height of the drain outlet 6, and the connecting section 72 extends downwards from the side ditch 5 towards the other side of the road 4. The siphon activation point is set at the connection between the water storage section 71 and the connecting section 72. When heavy rain causes the water level in the side ditch 5 to rise and the water level is higher than the height of the connection point, the water drives the air to be discharged outwards at an accelerated speed through the connecting section 72 and the drainage section 73, thereby forming a local negative pressure to activate the siphon effect.

[0056] In one embodiment, the drain outlet 6 is circumferentially concave to form a bowl-shaped depression, and the siphon tube is connected to the bottom of the depression. The diameter of the depression is the same as the width of the side ditch 5. The full-width depression causes the water flow to converge towards the center along the entire transverse area of ​​the side ditch 5, forming a ring-shaped scouring vortex. This not only scours the area around the drain outlet 6 and accelerates the water flow into the drain outlet 6 for discharge, but also moves the mud, sand, and small debris at the bottom of both sides of the side ditch 5 towards the center, preventing debris from accumulating in dead corners between the side walls of the side ditch 5 and the drain outlet 6. This significantly improves the debris cleaning efficiency compared to a typical bottom drain outlet 6.

[0057] Specifically, in this embodiment, the recessed part is deepened by 50cm on the basis of the bottom of the side ditch 5 to form an arc-shaped bowl structure. The drain outlet 6 and the siphon pipe can be replaced with high-strength composite materials (such as carbon fiber reinforced polymer) to resist the wear and chemical corrosion of the eroding soil and rocks, thereby reducing the probability of blockage and extending the service life.

[0058] In this embodiment, as a further preferred embodiment, it also includes a intercepting ditch 1. A stepped platform 9 is provided on the slope 2, extending along the slope surface of the slope 2. The platform surface of the stepped platform 9 is parallel to the road 4. The intercepting ditch 1 is located at the top of the slope 2 and inside the stepped platform 9, and the intercepting ditch 1 is connected to the drainage ditch 3. The intercepting ditch 1 at the top of the slope directly intercepts natural precipitation, surface runoff, and shallow groundwater at the top of the slope 2, preventing such runoff from flowing disorderly across the slope and concentrating into the drainage ditch 5. The intercepting ditch 1 inside the stepped platform 9 further divides the slope 2 into multiple independent drainage units, intercepting the runoff in the middle section of the slope in stages, achieving three-level runoff control from the top to the middle to the bottom of the slope. Before the intercepting ditch 1 connects with the drainage ditch 3, a natural sedimentation space is formed. Large particles of silt and stones in the runoff from the top and middle sections can be deposited in the intercepting ditch 1 first, preventing them from directly entering the drainage ditch 3 and the drainage ditch 5 and causing pipe siltation. The intercepting ditch 1, combined with the flushing effect of the original drain outlet 6 bowl-shaped structure, achieves a dual anti-clogging effect, further reducing the risk of clogging in this embodiment.

[0059] like Figure 3 As shown, this embodiment also provides a design method for a siphon drainage structure based on an existing road drainage system, applied to the siphon drainage structure based on an existing road drainage system as described above, including the following steps:

[0060] S1. Obtain the location of the drainage ditch 3, and divide the side ditch 5 into multiple segmented side ditches based on the location of the drainage ditch 3, thereby determining the length of the segmented side ditch between adjacent drainage ditches 3; when the local flood flow exceeds the drainage capacity of the outlet 6 of the current segmented side ditch, the excess flood is discharged through the side ditch 5 to the next segmented side ditch to prevent the flood from overflowing onto the road surface and avoid the highway from becoming a temporary river.

[0061] S2. Obtain the preset number of drainage outlets in the segment side ditch, determine the layout spacing of drainage outlets 6 according to the length of the segment side ditch and the preset number of drainage outlets, and determine the layout position of drainage outlets 6 in the segment side ditch according to the layout spacing of drainage outlets 6.

[0062] S3. Obtain the inflow rate of the segmental ditch, and determine the inflow rate of a single drainage outlet 6 based on the inflow rate and the preset number of drainage outlets 6, thereby determining the drainage outlet radius; specifically, using the formula:

[0063]

[0064] In the formula, r1 is the radius of the discharge outlet, and Q is the inflow rate of a single discharge outlet 6. Let H be the flow coefficient of outlet 6. It can be obtained by referring to the table. H is the head and g is the acceleration due to gravity.

[0065] S4. Determine the siphon tube radius based on the drain outlet radius, obtain the minimum anti-clogging diameter of the siphon tube, and determine whether the siphon tube radius is greater than or equal to the minimum anti-clogging diameter; if yes, proceed to step S5; if no, increase the drain outlet radius by a preset increment and return to step S4; in this embodiment, the minimum anti-clogging diameter is 0.15m, and the preset increment is 0.05m; the relationship between the drain outlet radius and the siphon tube radius is: Where r2 is the radius of the siphon pipe and k is the siphon ratio, the optimal value is 1.8 (1.76~1.82 within the allowable error) to minimize the energy loss from the drain outlet 6 to the siphon pipe.

[0066] S5. Obtain the bending angle of the water storage section 71 of the siphon pipe, determine the siphon enhancement factor based on the bending angle, and determine the maximum drainage flow rate of the drain outlet 6 based on the drain outlet radius and the siphon enhancement factor.

[0067] S6. Determine whether the maximum drainage flow rate is greater than the inflow flow rate of the single drain outlet 6; if yes, the design is complete; if no, increase the radius of the drain outlet by a preset increment and return to step S4.

[0068] This application incorporates a verification process for the minimum anti-clogging pipe diameter and the drainage capacity of the drain outlet 6 into its design methodology. By matching the flow rate of the drain outlet 6 with the radius of the siphon pipe, it ensures that the flow velocity within the pipe is always higher than the critical anti-clogging velocity. This avoids clogging problems caused by insufficient pipe diameter and flow rate mismatch from the design source, solving the pain points of existing technologies that rely on experience-based design and have uncontrollable anti-clogging effects. Through a closed-loop logic of dividing the side ditch into sections, matching the flow rate with the drain outlet parameters, and verifying the siphon effect, the parameters of the drain outlet 6 can be adjusted according to local conditions, improving the design's adaptability and making it suitable for mountainous road scenarios with large altitude differences and complex terrain. By incorporating the siphon enhancement factor into the design system and quantitatively calculating the maximum drainage flow rate in conjunction with the drain outlet radius and the bending angle of the water storage section 71, it ensures that the drainage capacity of each section of the side ditch is precisely matched with the inflow flow rate, avoiding over-design or under-drainage, significantly improving the design reliability of this application, and enabling it to maintain stable performance under different rainfall intensities and different operating years.

[0069] In this embodiment, as a further step, step S2 specifically includes the following steps:

[0070] Obtain the preset distance between the beginning and end of the segmented ditch, and determine the positions of the first drainage outlet 6 and the last drainage outlet 6 in the segmented ditch based on the preset distance between the beginning and end; wherein, the preset distance between the beginning and end is the distance from the first drainage outlet 6 to the starting point of the segmented ditch and the distance from the last drainage outlet 6 to the ending point of the segmented ditch;

[0071] Obtain the preset number of drainage outlets in the segmented ditch, and determine the layout spacing of the drainage outlets 6 based on the length of the segmented ditch, the preset distance between the beginning and end, and the preset number of drainage outlets;

[0072] The placement of each drainage outlet 6 within the segmental ditch is determined based on the spacing between the outlets 6.

[0073] In this embodiment, the pre-set distance between the beginning and end is set to 10m, ensuring that all areas within the segmental ditch are covered by the drainage outlets 6, eliminating boundary blind spots. The specific formula for determining the spacing of the drainage outlets 6 is as follows:

[0074] ;

[0075] In the formula, L is the spacing between the drainage outlets 6. g N represents the length of the segmental ditch, and N represents the preset number of drainage outlets within the segmental ditch.

[0076] Based on the above formula, this embodiment calculates the layout of the drainage outlets 6 in each segment of the side ditch, and the results are shown in the table below:

[0077]

[0078] The spacing of the drainage outlets 6 was determined by calculation and is shown in the table. To ensure a unified construction standard, the spacing of the drainage outlets 6 will be used.

[0079] In this embodiment, step S3 further includes the following steps:

[0080] Obtain the inflow rate of the segmented ditch, and obtain the inflow rate of a single drainage outlet 6 based on the inflow rate and the preset number of drainage outlets;

[0081] Obtain the flow coefficient of the drain outlet 6, and calculate the radius of the drain outlet 6 based on the inflow rate of the single drain outlet 6 and the flow coefficient of the drain outlet 6.

[0082] The construction accuracy value is obtained, and the radius of the drain outlet is calculated based on the calculated radius value. In this embodiment, for ease of construction, the construction accuracy value is 0.05m. That is, when the calculated radius value is 0.28m, the drain outlet radius is converted to 0.3m; when the calculated radius value is 0.34m, the drain outlet radius is converted to 0.35m.

[0083] In one embodiment, step S5 specifically includes the following steps:

[0084] Obtain the bending angle of the water storage section 71 of the siphon pipe, and determine the siphon enhancement factor based on the bending angle; wherein, the siphon enhancement factor is determined by the bending angle, and the siphon enhancement factor... ∝sin θ θ is the bending angle;

[0085] Obtain the blockage probability model and discharge coefficient of the drain outlet 6. Based on the drain outlet radius, siphon enhancement factor, blockage probability model and discharge coefficient, establish a drain outlet discharge capacity calculation model. Determine the maximum drainage flow of the drain outlet 6 through the drain outlet discharge capacity calculation model.

[0086] In this embodiment, the specific calculation model for the discharge capacity of the drainage outlet is as follows:

[0087] ;

[0088] In the formula, For maximum drainage flow, For emission coefficients, The siphon enhancement factor is related to the bending angle and can be determined experimentally. In this embodiment, the bending angle is set to 90°. Approximately 1.3, This is a congestion probability model.

[0089] The blockage probability model is as follows:

[0090] ;

[0091] In this embodiment, when r1 ≥ 0.3m, <0.05.

[0092] The dimensions of the side ditch for each segment in this embodiment are calculated as follows:

[0093]

[0094] Where N is the preset number of drainage outlets in the segmental ditch, and Q in This refers to the inflow rate of the segmental ditch.

[0095] In one embodiment, as a further preferred embodiment, the step S5 is further included by the following step:

[0096] Obtain the duration of the strongest local rainfall, and determine the total drainage volume of the outlet 6 based on the rainfall duration and the maximum drainage flow rate;

[0097] The intensity of the strongest local rainfall and the equivalent catchment area of ​​outlet 6 are obtained to determine the total rainfall of outlet 6;

[0098] The first verification value for the spacing of the drainage outlets 6 is established based on the total drainage volume and total rainfall.

[0099] Obtain the slope and hydraulic radius of the side ditch 5, and determine the flow velocity of the water in the side ditch 5 based on the slope and hydraulic radius;

[0100] Obtain the discharge response time of the water flow, and establish a second verification value for the spacing of the discharge outlets 6 based on the flow velocity and the discharge response time;

[0101] By comparing the first verification value and the second verification value to obtain the minimum verification value, it is determined whether the spacing of the drain outlets 6 is greater than or equal to the minimum verification value; if not, the spacing of the drain outlets 6 is increased so that the spacing of the drain outlets 6 is greater than or equal to the minimum verification value.

[0102] Specifically, the minimum verification value is obtained using the following formula:

[0103] ;

[0104] ;

[0105] In the formula, L min The minimum validation value is given by T, where T is the rainfall duration, i is the rainfall intensity, B is the equivalent catchment area, and v is the minimum validation value. 边沟 Let t be the velocity of the water flow in the ditch. 响应 In this embodiment, t represents the emission response time. 响应 Set to 10 minutes, meaning the water flow is discharged within 10 minutes, n is the Manning roughness coefficient, and the standard value of 0.013 is used in this embodiment, R is the hydraulic radius, and S is the slope of slope 2.

[0106] In this embodiment, the first verification value, through a quantitative comparison of total drainage volume and total rainfall, ensures that the system can still quickly drain the collected water under extreme conditions such as the strongest local rainfall, avoiding overflow of the side ditch 5 and rainwater seepage into the roadbed 8 due to unexpected rainfall intensity, thus improving the safety redundancy of the design. The second verification value calculates the water flow velocity by combining the slope and hydraulic radius of the side ditch 5, and then reverses to deduce the maximum allowable spacing of the drainage outlets 6, ensuring that the water flow reaches the drainage outlets 6 within the discharge response time, avoiding slow water flow transmission and the formation of local stagnant water areas due to the gentle slope and small hydraulic radius of the side ditch 5. It is particularly suitable for scenarios with large changes in the slope of the side ditch 5 in mountainous roads, ensuring that the spacing of the drainage outlets 6 in different slope sections can meet the requirements for rapid water flow collection and drainage, ensuring consistent drainage efficiency throughout the area. Traditional designs only focus on the static matching of the flow rate and inflow rate of the drainage outlets 6, ignoring the impact of the water flow transmission time within the side ditch 5 on drainage efficiency. This embodiment ensures "sufficient capacity" through a first verification value (total drainage volume ≥ total rainfall) and ensures "timely response" through a second verification value (water flow transmission time ≤ discharge response time). The dual verification avoids the problems of "sparse spacing leading to local water accumulation" or "sparse spacing causing engineering waste," upgrading the layout spacing design of the drainage outlets 6 from "empirical estimation" to "data-driven," thereby adapting to the complex working conditions of varying slopes and uneven flow in the mountain roadside ditches 5.

[0107] As a further preferred embodiment, the following steps are included after step S5:

[0108] S61. Obtain the radius of the drainage outlet of each segment of the ditch, and obtain the blockage probability of the drainage outlet 6 in each segment of the ditch according to the blockage probability model.

[0109] S62. Obtain the standard value of the blockage probability, and determine whether the blockage probability of the drain outlet 6 in each segment of the ditch is less than or equal to the standard value of the blockage probability. If yes, the blockage probability is verified. If no, the radius of the drain outlet is increased by a preset increment, and the process returns to step S61.

[0110] In this embodiment, drainage tests were conducted on all segmental ditches designed in the above embodiments to verify the drainage efficiency of the segmental ditches. The test results are shown in the table below:

[0111]

[0112] Q in the table real As shown in the actual drainage flow rate, it can be seen that the drainage efficiency of all segmented ditches designed in the above embodiments is greater than 95%, which meets the engineering requirements.

[0113] The above are merely preferred embodiments of the present invention and do not limit the scope of protection of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A design method for a siphon drainage structure based on an existing road drainage system, applicable to a siphon drainage structure based on an existing road drainage system, comprising a drainage ditch, a side ditch, multiple drainage outlets and a siphon pipe, wherein the drainage ditch is located on a slope and extends downwards from the slope, the side ditch is located on the side of the road near the slope, the drainage ditch is connected to the side ditch, and the drainage outlets are evenly distributed along the longitudinal direction of the side ditch at the bottom of the side ditch; The siphon pipe is buried under the road, extending from one side of the road ditch to the other side. The siphon pipe includes a water-storing section, a connecting section, and a drainage section connected sequentially along its extension direction. Both ends of the water-storing section bend upwards, with one end connected to the drain outlet and the other end connected to the connecting section. The highest point of the connecting section is higher than the bottom of the drain outlet. The drainage section is connected to the connecting section, and its downward inclination angle is greater than that of the connecting section, allowing for rapid drainage of water flowing into the connecting section. Its characteristic is that… The design method for a siphon drainage structure based on an existing road drainage system includes the following steps: S1. Obtain the location of the drainage ditch, and divide the side ditch into multiple segmented side ditches according to the location of the drainage ditch, thereby determining the length of the segmented side ditch located between adjacent drainage ditches. S2. Obtain the preset number of drainage outlets in the segment side ditch, determine the layout spacing of the drainage outlets according to the length of the segment side ditch and the preset number of drainage outlets, and determine the layout position of the drainage outlets in the segment side ditch according to the layout spacing of the drainage outlets. S3. Obtain the inflow rate of the segmented ditch, and obtain the inflow rate of a single drainage outlet based on the inflow rate and the preset number of drainage outlets, thereby determining the radius of the drainage outlet; S4. Determine the siphon tube radius based on the drain outlet radius, obtain the minimum anti-clogging diameter of the siphon tube, and determine whether the siphon tube radius is greater than or equal to the minimum anti-clogging diameter; if yes, proceed to step S5; if no, increase the drain outlet radius by a preset increment and return to step S4. S5. Obtain the bending angle of the water storage section of the siphon pipe, determine the siphon enhancement factor based on the bending angle, and determine the maximum drainage flow rate of the drain outlet based on the drain outlet radius and the siphon enhancement factor. S6. Determine whether the maximum drainage flow rate is greater than the inflow flow rate of the single drain outlet; if yes, the design is complete; if no, increase the radius of the drain outlet by a preset increment and return to step S4. The relationship between the radius of the drain outlet and the radius of the siphon pipe is as follows: ； Obtain the bending angle of the water-storing section of the siphon pipe, and determine the siphon enhancement factor based on the bending angle; wherein, the siphon enhancement factor is determined by the bending angle, and the siphon enhancement factor... ∝sinθ, where θ is the curvature angle; Obtain the blockage probability model and discharge coefficient of the drain outlet, establish a drain outlet discharge capacity calculation model based on the drain outlet radius, siphon enhancement factor, blockage probability model and discharge coefficient, and determine the maximum drainage flow of the drain outlet through the drain outlet discharge capacity calculation model; The calculation model for the discharge capacity of the drainage outlet is as follows: 。 2. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, The height of the connection between the water storage section and the connecting section is higher than the bottom height of the drain outlet, and the connecting section extends downward from the side ditch to the other side of the road.

3. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, The drain outlet is circumferentially concave to form a bowl-shaped depression, and the siphon tube is connected to the bottom of the depression. The diameter of the depression is the same as the width of the side ditch.

4. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, It also includes a drainage ditch, and a stepped platform is provided on the slope. The stepped platform extends along the slope surface and the platform surface is parallel to the road. The drainage ditch is set at the top of the slope and inside the stepped platform, and the drainage ditch is connected to the drainage ditch.

5. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, Step S2 specifically includes the following steps: Obtain the preset distance between the beginning and end of the segmented ditch, and determine the positions of the first and last drainage outlets in the segmented ditch based on the preset distance between the beginning and end; wherein, the preset distance between the beginning and end is the distance from the first drainage outlet to the starting point of the segmented ditch and the distance from the last drainage outlet to the ending point of the segmented ditch; Obtain the preset number of drainage outlets in the segmented ditch, and determine the layout spacing of the drainage outlets based on the length of the segmented ditch, the preset distance between the beginning and end, and the preset number of drainage outlets; The placement of each drainage outlet within the segmental ditch is determined based on the spacing between the outlets.

6. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, Step S3 specifically includes the following steps: Obtain the inflow rate of the segmented ditch, and obtain the inflow rate of a single drainage outlet based on the inflow rate and the preset number of drainage outlets; Obtain the flow coefficient of the drain outlet, and calculate the radius of the drain outlet based on the inflow rate of the individual drain outlet and the flow coefficient of the drain outlet. Obtain the construction accuracy value, and convert the radius calculation value to obtain the drainage outlet radius based on the construction accuracy value.

7. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, Following step S5, the following steps are also included: Obtain the duration of the strongest local rainfall, and determine the total drainage volume of the outlet based on the rainfall duration and the maximum drainage flow rate; The intensity of the strongest local rainfall and the equivalent catchment area of ​​the drainage outlet are obtained to determine the total rainfall at the drainage outlet; A first verification value for the spacing of the drainage outlets is established based on the total drainage volume and total rainfall. Obtain the slope and hydraulic radius of the ditch, and determine the flow velocity of the water in the ditch based on the slope and hydraulic radius; Obtain the discharge response time of the water flow, and establish a second verification value for the spacing of the discharge outlets based on the flow velocity and the discharge response time; By comparing the first verification value and the second verification value to obtain the minimum verification value, it is determined whether the layout spacing of the drain outlets is greater than or equal to the minimum verification value; if not, the layout spacing of the drain outlets is increased so that the layout spacing of the drain outlets is greater than or equal to the minimum verification value.

8. The design method for a siphon drainage structure based on an existing road drainage system according to claim 1, characterized in that, Following step S5, the following steps are also included: S61. Obtain the radius of the drainage outlet of each segment of the ditch, and obtain the blockage probability of the drainage outlet in each segment of the ditch according to the blockage probability model. S62. Obtain the standard value of the blockage probability, and determine whether the blockage probability of the drainage outlet in each segment of the ditch is less than or equal to the standard value of the blockage probability. If yes, the blockage probability is verified. If no, the radius of the drainage outlet is increased by a preset increment, and the process returns to step S61.

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