An evaporation pond for municipal levee roads and a design method

Abstract

The present invention provides an evaporation pond for a municipal dike road. Wetland plants are planted in the evaporation pond. Flanges are provided on both sides of the top of the evaporation pond. The flanges are placed on the ground surface to support the evaporation pond and connect with the toe of the road slope. Interfaces are provided at both ends of the evaporation pond. The interfaces are used to connect with the road drainage ditch to introduce water into the evaporation pond. By utilizing the transpiration of wetland plants, the evaporation pond greatly improves the evaporation amount per unit area, thus solving the core problem of using evaporation ponds for road drainage in rainy areas.

Description

Technical Field

[0001] The present invention relates to the technical field of evaporation ponds for dike roads, and particularly relates to an evaporation pond for municipal dike roads and a design method thereof. Background Art

[0002] Municipal road drainage mainly includes the following six methods: municipal pipe network drainage, surface drainage, manual pumping drainage, drainage to natural aquifers through infiltration wells, drainage to natural water bodies, and evaporation drainage through evaporation ponds. For municipal roads that also serve as dikes, their drainage is restricted in many ways: due to the anti-seepage requirements of dikes, it is not possible to lay municipal pipe networks for drainage; in order to prevent waterlogging at the toe of the dike from affecting the overall stability of the dike body, surface drainage is not allowed either; manual pumping drainage consumes a large amount of labor and equipment, with high costs and inconvenient maintenance, and generally can only be used as a temporary measure during extremely heavy rainfall and cannot be used as a conventional means; the areas where dikes are located are all waterfront areas with high groundwater levels, not meeting the basic conditions for infiltration well drainage; if there are suitable natural water bodies for drainage nearby, the rainwater can be treated and drained, but dikes are often located within water source protection areas, strictly restricting drainage. In summary, for municipal roads that also serve as dikes, setting up evaporation ponds is often the only feasible drainage method.

[0003] Setting up evaporation ponds in municipal dike road projects is restricted by the gentle terrain. According to the road drainage design specifications, the longitudinal slope of the bottom of the road drainage ditch should not be less than 0.3%. However, at the waterfront dike banks with extremely gentle terrain, the longitudinal slope of the terrain is extremely small, almost flat. Because the buried depth of the bottom of the drainage ditch increases with the increase of the drainage distance during the setting of the drainage ditch, when the distance is 500 meters, the over-excavation depth of a section of the drainage ditch is 1.5m, which not only weakens the stability of the road toe slope, but also the water outlet elevation is too low, increasing the difficulty of drainage. Therefore, in the dike road projects in flat areas, it is advisable to adopt the drainage method with small spacing and multiple outlets, and arrange small evaporation ponds at multiple points.

[0004] In areas with arid climate and strong sunlight, small evaporation ponds can achieve good drainage effects. However, in rainy areas, the difference between the evaporation amount and the precipitation amount is small, and the designed evaporation amount of small evaporation ponds often fails to meet the requirements of the road drainage specifications. Therefore, some projects have adopted unconventional large evaporation ponds, with the area of a single pond body exceeding 800 ㎡. To avoid affecting the subgrade stability, the edge of the evaporation pond needs to be more than 20m away from the road toe line. Not only is the cost extremely high, but also the land occupation is extremely large, requiring dozens to hundreds of meters beyond the road red line range. It is possible to allocate a large amount of land in suburban or urban fringe areas, but for the riverside plots within the city where every inch of land is precious, it is impossible to set up large evaporation ponds, and the designed evaporation amount of small evaporation ponds is difficult to meet the requirements of the road drainage specifications. Summary of the Invention

[0005] The object of the present invention is to address the deficiencies of the prior art and provide an evaporation pond for municipal levee roads and a design method. The evaporation pond utilizes the transpiration of wetland plants to significantly increase the evaporation rate per unit area of the evaporation pond, thereby solving the core problem of using evaporation ponds for road drainage in rainy areas.

[0006] The present invention provides an evaporation pond for municipal levee roads. Wetland plants are planted in the evaporation pond. Flanges are provided on both sides of the top of the evaporation pond. The flanges are placed on the ground surface to support the evaporation pond and connect with the toe of the road slope. Interfaces are provided at both ends of the evaporation pond. The interfaces are used to connect with the road drainage ditch to introduce water into the evaporation pond.

[0007] Further, a planting plate is provided in the evaporation pond. A plurality of planting holes are formed in the planting plate. A plurality of support legs are provided at the bottom of the planting plate. The support legs are placed on the bottom of the evaporation pond. The edge of the planting plate is in close contact with the inner wall of the evaporation pond. A water retention layer is formed between the planting plate and the bottom of the evaporation pond. The roots of the wetland plants are inserted into the water retention layer for soilless cultivation.

[0008] Further, the evaporation pond is in a long strip shape. Along the length direction, it includes two end segments and a plurality of standard segments provided between the two end segments. The end segments and the standard segments are both prefabricated structures. The plurality of standard segments are detachably connected to each other. The end segments and the standard segments are detachably connected to each other.

[0009] Further, the standard segment is a U-shaped thin-walled structure. First grooves and first protrusions are respectively provided on the two end faces of the standard segment connected to other segments. First mounting holes are respectively provided on the upper and lower sides of the first groove at the flange position. Second mounting holes corresponding to the first mounting holes are formed on the first protrusion. The end segment is a U-shaped thin-walled structure with one side closed. The interface is provided on the end face of the closed side of the end segment. The end segment includes a head segment and a tail segment. A second protrusion is provided on the end face of the non-closed side of the head segment. Third mounting holes corresponding to the first mounting holes are formed on the second protrusion. A second groove is provided on the end face of the non-closed side of the tail segment. Fourth mounting holes corresponding to the second mounting holes are formed on the second groove.

[0010] Further, continuous waterproof strips are provided in both the first groove and the second groove.

[0011] Further, the flange of the evaporation pond is subjected to structural strengthening treatment.

[0012] The present invention also provides a design method for an evaporation pond for municipal levee roads, including the following steps:

[0013] S1. Determine the length L of the slope-changing section of the drainage ditch according to the surface longitudinal slope I of the section where the evaporation pond is to be arranged e , the longitudinal slope I of the bottom of the drainage ditch d , the over-excavation depth H of the bottom of the ditch c ;

[0014] S2. Determine the dimensions of the evaporation pond section: length L z , top width D t , bottom width D z , pond depth H z , cross-sectional area S z , the height H between the planting board and the bottom of the evaporation pond j and the width D at the planting board of the evaporation pond j . Assume the number of sections of the evaporation pond is N, including 2 end sections and N - 2 standard sections;

[0015] S3. Calculate the monthly transpiration amount Q of the wetland plants in each section of the evaporation pond t ;

[0016] S4. Calculate the catchment area S of this section according to the road dimensions and evaporation pond dimensions of this section w ;

[0017] S5. Calculate the monthly maximum rainfall volume Q of this section according to the maximum monthly rainfall H r at the project location and the average monthly evaporation volume H z , where Q s = S w × H r and the monthly average evaporation volume Q z = N × L z × D t × H z ;

[0018] S6. Calculate the minimum value of N according to Q s ≤ Q z + Q r + 0.5 × Q c + Q t × N, that is, the minimum number of sections of the evaporation pond in this section, where Q r is the seepage water volume of the evaporation pond, Q c is the volume of the evaporation pond. Considering that the planting of wetland plants occupies part of the evaporation pond capacity, the evaporation pond volume Q c = 0.6 × S z × N × L z .

[0019] Further, the step S1 includes: when I e ≥ I dWhen the road is in a certain situation, the drainage ditch is designed with a single slope. The drainage ditch does not need to be overexcavated. The position of the evaporation pond is arranged according to the available space outside the road red line, and the section length L is determined; when I e <I d When it is in a certain range, the drainage ditch is designed with a double slope. The slope length L of the downslope section s ≤H c / (I d -I e ), and the slope length L of the upslope section n ≤H c / (I d +I e ). The length L of the slope-changing section of the drainage ditch = L s +L n .

[0020] Furthermore, the step S3 includes: according to the leaf surface area S l per square meter of the planting area at the appropriate planting density of the selected wetland plants, the daytime transpiration intensity T d , the nighttime transpiration intensity T n , and the area S j of each section of the planting board, determine the monthly transpiration volume Q t of each section of the evaporation pond = S l ×S j ×(T d × sunshine duration + T n × nighttime duration)×30; where S j = L z ×D j , and S j is the area of the planting board of each section of the evaporation pond;

[0021] Furthermore, the step S4 includes: according to the half-width W r of the road, the slope height H t of this section, the slope ratio I s , the top width D b of the drainage ditch, and the L obtained in step S1, the planned width W f of the slope toe protection transition section, the number of evaporation pond sections N, and the top width D t of the evaporation pond, calculate the catchment area S w of this section of the road = (W r +H t ×I s )×(L+N×L z )+L×D b +N×(D t +W f ).

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention sets wetland plants in the evaporation pond. By utilizing the transpiration of wetland plants, the evaporation amount per unit area of the evaporation pond is significantly increased, enabling the dike roads in rainy areas to meet the requirements of road drainage specifications by setting up small evaporation ponds, thus solving the problems of a large amount of land occupation for setting up large evaporation ponds on dike roads in rainy areas and the inability of traditional small evaporation ponds to meet road drainage specifications.

[0024] 2. The wetland plants of the present invention adopt soilless cultivation design. On the one hand, it avoids the occupation of the evaporation pond volume by the cultivation substrate. On the other hand, a relatively non-evaporative small water retention layer is formed in the area below the planting rack. When encountering continuous drought weather, it can prevent the pond water from drying up and causing a large area of death of wetland plants.

[0025] 3. The wetland plants of the present invention enhance the landscape along the road and increase the road greening rate while serving as road drainage facilities.

[0026] 4. The present invention sets the evaporation pond into two end segments and multiple standard segments. Both the end segments and the standard segments are prefabricated parts, which can be prefabricated in batches off-site. At the construction site, the evaporation pond can be assembled with end segments and standard segments according to the designed length of the evaporation pond, with high construction efficiency.

[0027] 5. The evaporation pond of the present invention has a small cross-section, occupies less land, and has few layout restrictions. Therefore, the connection relationship between the drainage ditch and the ground surface can be given priority to determine the layout spacing of the evaporation pond, which not only simplifies the design process but also avoids large over-excavation of the drainage ditch; moreover, it has little impact on the subgrade stability. Under the conditions of non-soft foundation and a road fill height not exceeding 10m, the overall stability coefficient of the evaporation pond and the road has a large safety redundancy compared with the allowable value of the specification, and no stability calculation is required, nor is it necessary to additionally set support structures such as retaining walls; in addition, the required foundation pit shape of the evaporation pond is regular, and conventional road construction machinery can be used for excavation.

[0028] 6. The end segments and the standard segments of the present invention have the same and small sizes, and ordinary transport vehicles can be used for transportation during transportation. Since multiple segments can be stacked together, the transportation quantity of the transport vehicle can be increased.

[0029] 7. The present invention sets waterproof strips in the first groove and the second groove to make the splicing joint of adjacent segments have self-waterproof property, thus eliminating the process of doing an external waterproof layer and further saving the cost and construction period.

[0030] 8. After the flange of the present invention is strengthened structurally, the opening on the flange can be used as a lifting hole, which is convenient for hoisting and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the overall plane layout drawing of the road in the embodiment of the present invention;

[0032] Figure 2 is Figure 1 the A-A sectional view of;

[0033] Figure 3 is the isometric view when the standard segment number of the evaporation pond of the present invention is one;

[0034] Figure 4 is the isometric view of the standard segment of the present invention;

[0035] Figure 5 is the front view of the standard segment of the present invention;

[0036] Figure 6 is the side view of the standard segment of the present invention;

[0037] Figure 7 is the top view of the standard segment of the present invention;

[0038] Figure 8 is the isometric view of the head segment of the present invention;

[0039] Figure 9 is the isometric view of the tail segment of the present invention;

[0040] Figure 10 is Figure 9 the enlarged view at C in;

[0041] Figure 11 is the isometric view of the planting plate and the support legs of the present invention;

[0042] Figure 12 is the top view of the planting plate of the present invention;

[0043] Figure 13 is the side view of the slope-changing segment of the drainage ditch in the example of the present invention designed with a single slope;

[0044] Figure 14 is the side view of the slope-changing segment of the drainage ditch in the example of the present invention designed with a double slope;

[0045] Figure 15 is Figure 14 the comparison diagram of the A-A section (standard section of the drainage ditch) and the B-B section (the drainage ditch reaches the maximum over-excavation depth H c ) in;

[0046] Reference numerals: 1 - evaporation pond; 101 - head segment; 102 - tail segment; 103 - standard segment; 104 - interface; 105 - flange; 106 - first groove; 107 - first protrusion; 108 - first mounting hole; 109 - second mounting hole; 110 - second protrusion; 111 - third mounting hole; 112 - second groove; 113 - fourth mounting hole; 114 - bolt; 115 - waterproof strip; 116 - planting plate; 117 - support leg; 118 - planting hole; 2 - slope foot protection transition section; 201 - surface layer; 202 - intermediate layer; 203 - waterproof bottom layer; 3 - wetland plants; 4 - ground surface; 5 - road slope; 6 - drainage ditch. Detailed implementation manners

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] As Figure 1 、 2 shown, an evaporation pond for a municipal dike road, wetland plants 3 are planted in the evaporation pond 1, flanges 105 are arranged on both sides of the top of the evaporation pond 1, and the flanges 105 are placed on the ground surface 4 to support the evaporation pond 1 and connect with the slope foot of the road slope 5. Interfaces 104 are arranged at both ends of the evaporation pond 1, and the interfaces 104 are used to connect with the road drainage ditch 6 to introduce water into the evaporation pond 1.

[0049] It should be noted that currently, the main applications of wetland plants in roads and ancillary projects are still as greening landscapes, biological filters in constructed wetlands or bioretention ponds, and their transpiration has not been used for drainage. Transpiration is the process by which water is lost from the surface of living plants in the form of water vapor into the atmosphere. Different from the evaporation process in physics, transpiration is not only affected by external environmental conditions but also regulated and controlled by the plants themselves. The transpiration of the leaves of some common wetland plants is strong, and even under partial shading conditions, a large transpiration intensity can be achieved.

[0050] Specifically, the wetland plants 3 should be selected as local dominant emergent plant varieties with high transpiration intensity, pollution tolerance and easy survival. The evaporation pond 1 is buried below the ground surface 4 and is located outside the road slope 5. The flange 105 of the evaporation pond 1 close to the road is smoothly connected to the slope foot protection transition section 2. The structural form of the slope foot protection transition section 2 is the same as that of the road slope 5 protection structure, that is, it includes a surface layer 201, an intermediate layer 202 and a waterproof bottom layer 203 from top to bottom. The surface layer 201 is aligned with the flange 105. The slope foot protection transition section 2 slopes gently towards the main body of the evaporation pond 1 perpendicular to the road axis, facilitating the collection of slope water into the main body of the evaporation pond 1. The flange 105 of the evaporation pond 1 far from the road is placed on the ground. The road drainage ditch 6 is connected to the evaporation pond 1 through the interfaces 104 at both ends of the evaporation pond 1.

[0051] It can be understood that for the dike roads in rainy areas, the difference between the evaporation amount and the precipitation amount is small, and only small evaporation ponds 1 can be set. Relying solely on the evaporation effect of the small evaporation ponds 1 cannot meet the requirements of the road drainage specification. Therefore, by planting wetland plants 3 in the evaporation ponds 1 and utilizing the transpiration effect of the wetland plants 3, the evaporation amount per unit area of the evaporation ponds 1 can be greatly increased, enabling the dike roads in rainy areas to also meet the requirements of the road drainage specification by setting small evaporation ponds 1, thus solving the problem of a large amount of land use for setting large evaporation ponds 1 on the dike roads in rainy areas and the problem that traditional small evaporation ponds 1 cannot meet the road drainage specification. In addition, while serving as a road drainage facility, the evaporation pond 1 improves the road landscape along the line and increases the road greening rate.

[0052] In some embodiments, as Figure 11 shown, a planting plate 116 is arranged in the evaporation pond 1. A plurality of planting holes 118 are formed in the planting plate 116. A plurality of support legs 117 are arranged at the bottom of the planting plate 116. The support legs 117 are placed on the bottom of the evaporation pond 1. The edge of the planting plate 116 is closely attached to the inner wall of the evaporation pond 1. A water retention layer is formed between the planting plate 116 and the bottom of the evaporation pond 1. The roots of the wetland plants 3 are inserted into the water retention layer for soilless cultivation.

[0053] Specifically, as Figure 12As shown, the planting holes 118 are arranged in a matrix throughout the entire planting plate 116, so that different types of wetland plants 3 can be planted at different densities. The planting plate 116 is made of transparent or translucent synthetic materials. The wetland plants 3 can be directly planted in the planting holes 118 of the planting plate 116, or their roots can be first fixed in a mesh planting bag, and then the planting bag is hung in the planting holes 118. Through soilless cultivation, the cultivation matrix is ​​prevented from occupying the volume of the evaporation pond 1, and a small water-retaining layer that is relatively difficult to evaporate is formed in the area below the planting plate 116. When encountering continuous drought weather, the evaporation of pond water and the large-scale death of wetland plants 3 can be avoided.

[0054] like Figure 3 As shown, in some embodiments, the evaporation pond 1 is in the shape of an elongated strip, and includes two end segments and a plurality of standard segments 103 arranged between the two end segments along the length direction. The end segments and the standard segments 103 are both prefabricated structures, and the plurality of standard segments 103 are detachably connected to each other, and the end segments and the standard segments 103 are detachably connected to each other.

[0055] It should be noted that currently, evaporation ponds are usually cast-in-place monolithic concrete ponds or flexible structure ponds with geomembranes laid on the bottom. The former is the most common in engineering projects, with mature technology and a thick and durable structure. It requires formwork and maintenance during construction, and the construction period is relatively long; the latter has a thin structure, low cost, simple construction, and can be used as soon as it is laid, but it is not resistant to floating and is not resistant to plant root puncture. It is prone to aging due to long-term exposure to the sun, and its lifespan is difficult to reach the design service life of the road. It also has no slope support capacity, so it is often used in various temporary gentle slope ponds. There is currently no precedent for using prefabricated thin-walled structures for evaporation ponds.

[0056] It can be understood that by configuring the evaporation pool 1 to include two end segments and a plurality of standard segments 103, no matter how long the evaporation pool 1 is, it can be assembled using the end segments and the standard segments 103, and can be prefabricated in batches outside the construction site. By precalculating the length of the evaporation pool 1 required for each road section, different numbers of standard segments 103 and two end segments can be directly assembled, and the construction efficiency is high. Since the segments are detachable, it is easy to replace a segment when it is damaged. In addition, since each segment is small in size and can be stacked, it can be transported by an ordinary transport vehicle. The foundation pit corresponding to the evaporation pool 1 has a regular shape and can also be excavated using conventional road construction machinery, thereby reducing transportation and construction costs.

[0057] Furthermore, if Figures 4 to 7As shown, the standard segment 103 is a U-shaped thin-walled structure. On the two end faces where the standard segment 103 is connected to other segments, a first groove 106 and a first protrusion 107 are respectively provided. On both the upper and lower sides of the flange 105 in the first groove 106, first mounting holes 108 are provided. On the first protrusion 107, second mounting holes 109 corresponding to the first mounting holes 108 are provided. The end segment is a U-shaped thin-walled structure with one side closed, and the interface 104 is provided on the end face of the closed side of the end segment, as Figure 8 , 9 shown. The end segment includes a head segment 101 and a tail segment 102. On the end face of the unclosed side of the head segment 101, a second protrusion 110 is provided. On the second protrusion 110, third mounting holes 111 corresponding to the first mounting holes 108 are provided. On the end face of the unclosed side of the tail segment 102, a second groove 112 is provided. On the second groove 112, fourth mounting holes 113 corresponding to the second mounting holes 109 are provided.

[0058] Specifically, the end segment and the standard segment 103 are made of a lightweight synthetic material with properties of resistance to sun exposure, freezing, impermeability, waterproofness and certain strength, such as glass fiber reinforced concrete. The end segment and the standard segment 103 have exactly the same dimensions, and the dimensions of length, width and height are preferably between 1.8 and 2.3 m, and they can be stacked, which is convenient for batch transportation by engineering vehicles. The planting plates 116 are arranged corresponding to the segments. The length of each planting plate 116 is equal to the length of each segment, and it is closely attached to the segment in the width direction.

[0059] It can be understood that when splicing adjacent segments, by inserting the protrusion of the previous segment into the groove of the next segment, the mounting holes on the flanges 105 of the adjacent segments are aligned, and the adjacent segments can be fixedly connected together by bolts 114, and the construction efficiency is extremely high.

[0060] Furthermore, as Figure 10 shown, continuous waterproof strips 115 are provided in both the first groove 106 and the second groove 112.

[0061] Specifically, continuous waterproof strips 115 are provided along the entire length of the first groove 106 and the second groove 112. The waterproof strips 115 make the splicing joint of adjacent segments have self-waterproofness, thus eliminating the process of making an external waterproof layer, and further saving the cost and construction period.

[0062] Furthermore, the flange 105 of the evaporation pond 1 is subjected to structural strengthening treatment.

[0063] It is understandable that on the one hand, the flange 105 can serve as a structure for fixed connection of adjacent segments, and on the other hand, the flange 105 is also used to connect the transition section 2 of the slope toe protection and support the entire evaporation pond 1. By strengthening the structure of the flange 105, the strength and stiffness of the flange 105 are improved, so that the flange 105 is not prone to fracture and damage when supporting the entire evaporation pond 1, and the above-mentioned first mounting hole 108, second mounting hole 109, third mounting hole 111, and fourth mounting hole 113 can be used as lifting holes for convenient lifting and installation.

[0064] The design method of the evaporation pond 1 described above includes the following steps:

[0065] S1. Determine the length L of the variable slope section of the drainage ditch 6 according to the longitudinal slope I of the ground surface 4 of the section where the evaporation pond 1 is to be arranged e , the longitudinal slope I of the bottom of the drainage ditch 6 d , the overexcavation depth H of the bottom of the ditch c ;

[0066] S2. Draw up the dimensions of the segments of the evaporation pond 1: length L z , top width D t , bottom width D z , pond depth H z , cross-sectional area S z , the height H between the planting plate 116 and the bottom of the evaporation pond 1 j and the width D at the planting plate 116 of the evaporation pond 1 j , assume that the number of segments of the evaporation pond 1 is N, including 2 end segments and 103N - 2 standard segments;

[0067] S3. Calculate the monthly transpiration amount Q of the wetland plants 3 in each segment of the evaporation pond 1 t ;

[0068] S4. Calculate the catchment area S of this section according to the road dimensions of this section and the dimensions of the evaporation pond 1 w ;

[0069] S5. Calculate the monthly maximum rainfall volume Q of this section according to the maximum monthly rainfall H r at the project location and the average monthly evaporation amount H z , where Q s = S w × H r and the monthly average evaporation volume Q z = N × L z × D t × H z ;

[0070] S6. According to Q s ≤ Q z + Q r + 0.5 × Q c + Qt ×N to calculate the minimum value of N, that is, the minimum number of segments of the evaporation pond 1 in this section, where Q r is the seepage water volume of the evaporation pond 1, Q c is the volume of the evaporation pond 1. Considering that the planted wetland plants 3 occupy part of the capacity of the evaporation pond 1, the volume Q of the evaporation pond 1 c = 0.6×S z ×N×L z .

[0071] Since the cross-section of the evaporation pond 1 of the present invention is small, occupies little land, has few layout restrictions, and has little impact on the subgrade stability, under the conditions of non-soft foundation and road filling height not exceeding 10 m, the overall stability coefficient of the evaporation pond 1 and the road has a large safety redundancy compared with the allowable value of the specification, and no stability calculation is required, nor is it necessary to additionally set support structures such as retaining walls. Therefore, the connection relationship between the drainage ditch 6 and the ground surface 4 can be preferentially considered to determine the layout spacing of the evaporation pond 1, which not only simplifies the design process but also does not cause large over-excavation of the drainage ditch 6.

[0072] It can be understood that the consumption of rainwater includes the evaporation of water, the transpiration of wetland plants 3, the seepage water volume of the evaporation pond 1, and the water storage of the evaporation pond 1 itself, and the source of rainwater is rainfall. Therefore, through the formula Q s ≤Q z +Q r +0.5×Q c +Q t ×N, the minimum number of segments of the evaporation pond 1 that need to be set can be obtained. Since the evaporation pond 1 within the dike range must be impermeable, Q r = 0. Considering that the planted wetland plants 3 occupy part of the capacity of the evaporation pond 1, the volume Q of the evaporation pond 1 c = 0.6×S z ×N×L z .

[0073] Furthermore, the step S1 includes: when I e ≥I d , as shown in Figure 13 , the drainage ditch 6 is designed with a single slope, and no over-excavation of the drainage ditch 6 is required. The position of the evaporation pond 1 is arranged according to the available space outside the road red line, and the segment length L is determined; when I e <I d , as shown in Figure 14 , 15 , the drainage ditch 6 is designed with a double slope, and the slope length L s ≤H c / (I d -I e ), and the reverse slope length L n ≤H c / (I d +Ie ),the length L of the slope-changing section of the drainage ditch 6 = L s +L n , due to the longitudinal slope I e of the ground surface 4 being less than the longitudinal slope I d of the bottom of the drainage ditch 6, it is necessary to over-excavate to ensure the longitudinal slope I d of the bottom of the drainage ditch 6. According to the set maximum over-excavation depth H c , the length L of the slope-changing section of the drainage ditch 6 can be calculated.

[0074] Further, the step S3 includes: according to the leaf surface area S l per square meter of the planting area of the selected wetland plant 3 at the appropriate planting density d , the daytime transpiration intensity T n , the nighttime transpiration intensity T j , and the area S t of each section of the planting plate 116 to determine the monthly transpiration volume Q l of each section of the evaporation pond 1 = S j ×S d ×(T n × sunshine duration + T j × nighttime duration)×30; where S z = L j ×D j , and S

[0075] is the area of the planting plate 116 of each section of the evaporation pond 1; r The step S4 includes: according to the half-width W t of the road, the height H s of this section of the slope, the slope ratio I b of the slope, the top width D f of the drainage ditch 6, and the L obtained in step S1, the width W t of the proposed slope foot protection transition section 2, the number of sections N of the evaporation pond 1, and the top width D w of the evaporation pond 1, calculate the catchment area S r of this section of the road = (W t + H s ×I z )×(L + N×L b ) + L×D t + N×(D f + W

[0076] The following is illustrated by a case in a certain actual project:

[0077] S1. In this embodiment, the longitudinal slope I e of the ground surface 4 = 0.1%, and the longitudinal slope I dTake the specification minimum value of 0.3%, and the overexcavation depth H at the bottom of the trench c Take 0.3 m, then there is:

[0078] Ie < Id, the drainage ditch 6 should be designed with a double slope;

[0079] The slope length L of the downslope section s ≤ H c / (I d - I e ) = 0.3 / 0.2% = 150 m;

[0080] The slope length L of the upslope section n ≤ H c / (I d + I e ) = 0.3 / 0.4% = 75 m;

[0081] The length L of the slope-changing section of the drainage ditch 6 = L s + L n = 150 + 75 = 225 m.

[0082] S2. Determine the dimensions of the evaporation pond 1 section:

[0083] In this embodiment, the length L z = the bottom width D z = 2 m, the top width D t = 2.2 m, the pond depth H z = 2 m, the cross-sectional area S z = 4.2 m 2 , the height H between the planting plate 116 and the bottom of the evaporation pond 1 j = 0.2 m, the width D at the planting plate 116 of the evaporation pond 1 j = 2.02 m, the area S of the planting plate 116 of each section of the evaporation pond 1 j = L z × D j = 2 × 2.02 = 4.04 m 2 . Suppose there are N sections of the evaporation pond 1 in this road section, including 2 end sections and 103N - 2 standard sections.

[0084] S3. In this embodiment, the wetland plant 3 is selected as calamus, and its recommended planting density is two buds per hole, about ten leaves per bud, the average leaf length is about 50 cm, and the leaf width is 0.8 cm. There are 32 planting holes 118 per square meter on the planting plate 116 in this embodiment; the converted leaf surface area S of the planting area per square meter l = 2 × 10 × 50 × 0.8 × 32 / 10000 m 2 = 2.56 m 2 ;

[0085] The transpiration intensity values when shading is 30% are safely selected, which are the daytime transpiration intensity T d = 3.03 mol / m 2 ·s, and the nighttime transpiration intensity T n = 0.3 mol / m 2 ·s; the molar mass of water is 18 g / mol, and the density is 1000 kg / m 3 ; converting the transpiration intensity unit from mol / m 2 ·s to m 3 / m 2 ·h gives:

[0086] T d = 3.03×18×3600 / 1000000 = 0.196 m 3 / m 2 ·h;

[0087] T n = 0.3×18×3600 / 1000000 = 0.019 m 3 / m 2 ·h;

[0088] Safely taking the daily sunshine duration = nighttime duration = 12 h, then: the monthly transpiration volume Q of each segment t = S l ×S j ×(T d ×sunshine duration + T n ×nighttime duration) = 2.56×4.04×(0.196×12 + 0.019×12)×30 = 803.4 m 3 .

[0089] S4. In this embodiment, the width W of the half-width road r = 30 m, the height H of this section of the slope t = 3 m, the slope ratio I of the slope s = 1:3, the top width D of the drainage ditch 6 b = 1 m, the length L of the variable slope section of the drainage ditch 6 = 225 m, the width W of the proposed slope foot protection transition section 2 f = 1 m, the top width D of the evaporation pond 1 t = 2.2 m, the length L of the evaporation pond 1 z = 2 m. Calculating the catchment area S of this section of the road w = (W r + H t ×I s )×(L + N×L z ) + L×D b + N×(D t + W f) = (30 + 3×3)×(225 + N×2) + 225×1 + N×(2.2 + 1) = 9000 + 81.2×Nm 2 。

[0090] S5. In this embodiment, the maximum monthly rainfall H at the project site r = 819.9 mm, and the average monthly evaporation H z = 124.5 mm. The calculated results are as follows:

[0091] The maximum monthly rainfall volume Q s = S w ×H r (9000 + 81.2×N)×819.9 / 1000 = 7379.1 + 66.58×Nm 3 ;

[0092] The average monthly evaporation volume Q z = N×L z ×D t ×H z = N×2×2.2×124.5 mm / 1000 = 0.55×N m 3 。

[0093] S6. According to the road drainage specification, it should be Qs ≤ Qz + Qr + 0.5×Qc + Qt×N, where Qr is the seepage volume of evaporation pond 1. Since evaporation pond 1 within the dike range must be impermeable, so Qr = 0. Considering that the planting of wetland plants 3 occupies part of the capacity of evaporation pond 1, thus the effective volume Q of evaporation pond 1 is conservatively reduced c = 0.6×S z ×N×L z = 0.6×4.2×N×2 = 5.04×N m 3 ;

[0094] Qs ≤ Qz + Qr + 0.5×Qc + Qt×N, that is, the maximum monthly rainfall volume ≤ the average monthly evaporation volume + the seepage volume of evaporation pond 1 + half of the storage volume of evaporation pond 1 (0.5×the effective volume of evaporation pond 1) + the total transpiration volume. Substituting the parameters from the previous steps, we have:

[0095] 7379.1 + 66.58×N ≤ 0.55×N + 0 + 0.5×5.04×N + 803.4×N

[0096] It is obtained that N ≥ 9.97. Rounding up, N = 10. That is, for this section of the road, a total of ten segments need to be set for evaporation pond 1, including eight standard segments 103 and two end segments. The total length of evaporation pond 1 is 20 m, and the total length of this section of the road = L + 20 = 245 m.

[0097] In this embodiment, the physical evaporation amount of the calculated segment is 5.5 m 3, and the transpiration amount of wetland plant 3 is 803.4×N = 8034m 3 , the transpiration amount of the same water area is 1461 times that of the physical evaporation amount. It can be seen that the present invention utilizes the transpiration of wetland plant 3 to greatly increase the evaporation amount per unit area of evaporation pond 1, thus solving the core problem of using evaporation pond 1 for road drainage in rainy areas.

[0098] In this embodiment, if the present invention is not adopted and a traditional large-volume evaporation pond 1 is used instead, assuming the area of evaporation pond 1 is S o , and the depth is 4m, then there is: Q s =(S o +(W r +H t ×I s )×245)×H r =S o ×0.8199 + 7834.14, Q z =S o ×H z =S o ×0.1245, Q c =4×S o , Q s ≤Q z +Q r +0.5×Q c +Q t ×N, where Q r =Q t =0, it can be obtained that S o ≥6005m 2 , and the floor area of evaporation pond 1 of the present invention is only N×L z ×D t =10×2×2.2 = 44m 2 , and the width outside the red line occupied is only 3.2m. It can be seen that compared with the traditional large evaporation pond 1, the present invention has a small area outside the red line and saves a large amount of land.

[0099] Due to the large floor area and many layout restriction conditions of the large evaporation pond 1, it is difficult to control the layout spacing. When the ground slope direction changes in a drainage section, the longitudinal slope of the drainage ditch 6 is difficult to accommodate the ground slope direction. On the one hand, it increases the design difficulty and workload, and on the other hand, it will cause the local overexcavation depth of the drainage ditch 6 to be too large. Since the present invention has a small cross-section, less land occupation and less layout restrictions, the connection relationship between the drainage ditch 6 and the ground surface 4 can be given priority to determine the layout spacing of the evaporation pond 1, which not only simplifies the design process, but also will not cause large overexcavation of the drainage ditch 6.

[0100] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A design method for an evaporation pond on a municipal levee road, characterized in that: It includes the following steps: S1. Determine the variable slope section length L of the drainage ditch (6) according to the longitudinal slope I of the ground surface (4) of the section where the evaporation pond (1) is to be arranged e and the longitudinal slope I of the bottom of the drainage ditch (6) d and the over-excavation depth H of the bottom of the ditch c ​ S2. Wetland plants (3) are planted in the evaporation pond (1). A planting plate (116) is arranged in the evaporation pond (1). The evaporation pond (1) includes two end segments and a plurality of standard segments (103) arranged between the two end segments along the length direction; Determine the dimensions of the segment of the evaporation pond (1): length L z , top width D t , bottom width D z , pond depth H z , cross-sectional area S z , the height H between the planting plate (116) and the bottom of the evaporation pond (1) j and the width D at the planting plate (116) of the evaporation pond (1) j , let the number of segments of the evaporation pond (1) be N, including 2 end segments and N - 2 standard segments (103); S3. Calculate the monthly transpiration volume Q of the wetland plants (3) in each segment of the evaporation pond (1). t ; S4. Calculate the catchment area S of this road section according to the road dimensions of this road section and the dimensions of the evaporation pond (1). w ; S5. Calculate the maximum monthly rainfall volume Q of this section according to the maximum monthly rainfall H at the project location r and the average monthly evaporation volume H z , where the maximum monthly rainfall volume Q s = S w ×H r and the average monthly evaporation volume Q z = N×L z ×D t ×H z ; S6. Calculate the minimum value of N, i.e., the minimum number of segments of the evaporation pond (1) in this section, according to Q s ≤Q z +Q r +0.5×Q c +Q t ×N, where Q r is the seepage water volume of the evaporation pond (1), Q c is the volume of the evaporation pond (1). Considering that the planted wetland plants (3) occupy part of the capacity of the evaporation pond (1), the volume Q c of the evaporation pond (1) = 0.6×S z ×N×L z .

2. The design method for an evaporation pond on a municipal levee road according to claim 1, characterized in that: The step S1 includes: when I e ≥I d , the drainage ditch (6) is designed with a single slope, the drainage ditch (6) does not need to be overexcavated, the position of the evaporation pond (1) is arranged according to the available space outside the road red line, and the section length L is determined; when I e <I d , the drainage ditch (6) is designed with a double slope, the slope length L of the downstream slope s ≤H c / (I d -I e ), the slope length L of the upstream slope n ≤H c / (I d +I e ), and the length L of the slope-changing section of the drainage ditch (6) = L s +L n .

3. The design method for an evaporation pond on a municipal levee road according to claim 1 or 2, characterized in that: The step S3 comprises: determining the leaf surface area S per square meter of the planting area of ​​the selected wetland plants (3) at an appropriate planting density; l , daytime transpiration intensity T d , night transpiration intensity T n , and the area S of each segment implant plate (116) j Determine the monthly transpiration Q of each segment of the evaporation pond (1) t =S l ×S j ×(T d ×Sunshine duration+T n × night time) × 30; where S j =L z ×D j , S j The area of ​​the planting plate (116) for each segment evaporation pond (1).

4. The design method for an evaporation pond on a municipal levee road according to claim 3, characterized in that: The said step S4 includes: according to the half-width of the road W r , the height H of this section of slope t , the slope ratio I of the slope s , the top width D of the drainage ditch (6) b , as well as L obtained in step S1, the width W of the proposed slope foot protection transition section (2) f , the number of segments N of the evaporation pond (1), the top width D of the evaporation pond (1) t , calculate the catchment area S of this section of the road w =(W r +H t ×I s )×(L+N×L z )+L×D b +N×(D t +W f ).

5. An evaporation pond for the design method of an evaporation pond on a municipal levee road according to any one of claims 1 to 4, characterized in that: Wetland plants (3) are planted in the evaporation pond (1). Flanges (105) are arranged on both sides of the top of the evaporation pond (1). The flanges (105) are placed on the ground surface (4) to support the evaporation pond (1) and connect with the toe of the road slope (5). Interfaces (104) are arranged at both ends of the evaporation pond (1). The interfaces (104) are used to connect with the road drainage ditch (6) to introduce water into the evaporation pond (1).

6. The evaporation pond according to claim 5, characterized in that: A planting plate (116) is arranged in the evaporation pond (1). A plurality of planting holes (118) are formed in the planting plate (116). A plurality of support legs (117) are arranged at the bottom of the planting plate (116). The support legs (117) are placed on the bottom of the evaporation pond (1). The edge of the planting plate (116) is closely attached to the inner wall of the evaporation pond (1). A water retention layer is formed between the planting plate (116) and the bottom of the evaporation pond (1). The roots of the wetland plants (3) are inserted into the water retention layer for soilless cultivation.

7. The evaporation pond according to claim 5 or 6, characterized in that: The evaporation pond (1) is in a long strip shape and includes two end segments and a plurality of standard segments (103) arranged between the two end segments along the length direction. Both the end segments and the standard segments (103) are prefabricated structures. The plurality of standard segments (103) are detachably connected to each other, and the end segments and the standard segments (103) are detachably connected to each other.

8. The evaporation pond according to claim 7, characterized in that: The standard segment (103) is a U-shaped thin-walled structure. On the two end faces of the standard segment (103) connected to other segments, a first groove (106) and a first protrusion (107) are respectively provided. On the upper and lower sides of the flange (105) in the first groove (106), first mounting holes (108) are respectively provided. On the first protrusion (107), a second mounting hole (109) corresponding to the first mounting hole (108) is provided. The end segment is a U-shaped thin-walled structure with one side closed. The interface (104) is provided on the end face of the closed side of the end segment. The end segment includes a head segment (101) and a tail segment (102). On the end face of the non-closed side of the head segment (101), a second protrusion (110) is provided. On the second protrusion (110), a third mounting hole (111) corresponding to the first mounting hole (108) is provided. On the end face of the non-closed side of the tail segment (102), a second groove (112) is provided. On the second groove (112), a fourth mounting hole (113) corresponding to the second mounting hole (109) is provided.

9. The evaporation pond according to claim 8, characterized in that: Continuous waterproof strips (115) are provided in both the first groove (106) and the second groove (112).

10. The evaporation pond according to claim 8 or 9, characterized in that: The flange (105) of the evaporation pond (1) is subjected to structural strengthening treatment.

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