Design method of rain and sewage diversion drainage pipeline

Abstract

The application relates to the technical field of municipal official website construction, and particularly discloses a design method of rainwater and sewage diversion drainage pipelines, which divides a drainage area into multiple catchment areas, designs multiple drainage pipelines for each catchment area, includes independently arranged rainwater pipelines and sewage pipelines, respectively designs the rainwater pipelines and the sewage pipelines, in the rainwater pipeline drainage capacity design, according to multiple design parameters of the rainwater pipelines, determines the rainwater pipeline drainage capacity of each catchment area, through the specific implementation content of the rainwater pipelines, verifies the implementation content of the rainwater pipelines through calculation to meet the rainwater pipeline drainage capacity requirement determined by the design, the drainage capacity of the sewage pipelines is designed, calculated and verified in the same way, through ensuring that the drainage capacity of each catchment area meets the requirement, the rainwater and sewage diversion drainage pipelines meet the rainwater and sewage discharge requirement of a preset municipal road area, the environmental pollution and water resource pollution are reduced, and the urban waterlogging risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline engineering, and in particular to a design method of rain and sewage diversion drainage pipeline. BACKGROUND

[0002] The underground drainage network is a basic infrastructure and lifeline that guarantees the normal operation of the city and is closely related to the daily life of residents and the urban environment. During the process of urban construction, some municipal roads do not have sewage pipelines laid under them, and the sewage in the municipal road area is mainly discharged through scattering or through simple treatment by septic tanks and the like. These discharge methods will cause some pollution to the environment. Rain and sewage mixing will also cause pipe clogging, affecting the urban flood control and drainage capacity. During the rainy season, situations such as road waterlogging and sewage backflow are likely to occur, affecting the urban environment and the travel of residents. Therefore, when the underground drainage network is set up, rain and sewage diversion plays an important role in improving the processing efficiency of the urban underground drainage network, protecting the environment and water resources, and improving the urban environment's flood control and drainage capacity.

[0003] During the design process of rain and sewage diversion drainage pipeline, the following problems exist: insufficient understanding of the geological conditions and topographical conditions of the construction site, insufficient consideration of pipe installation, and after the installation of rain and sewage diversion drainage pipeline, its drainage performance will also be affected. Moreover, the flow conditions of rainwater and sewage will also have a great impact on drainage, and due to the deviation between design specification requirements and actual implementation content, it will also affect the rain and sewage diversion effect. In addition, there is a lack of consideration of high-intensity continuous rainfall, and the rain and sewage diversion drainage pipeline is difficult to drain in time, increasing the risk of urban waterlogging. SUMMARY

[0004] One of the purposes of the present application is at least to provide a design method of rain and sewage diversion drainage pipeline, which divides the drainage area into multiple catchment areas and arranges independent rainwater pipelines and sewage pipelines for each catchment area. When the drainage capacity of each catchment area meets the requirements, the rain and sewage diversion drainage pipeline can meet the rain and sewage discharge requirements of the preset municipal road area, thereby reducing environmental and water resource pollution and reducing the risk of urban waterlogging.

[0005] In order to achieve the above-mentioned purposes, the technical solutions adopted by the present application include the following aspects.

[0006] A design method of rain and sewage diversion drainage pipeline, when designing rain and sewage diversion drainage pipeline for a drainage area, includes the following steps:

[0007] Step A: divide the drainage area into multiple catchment areas, and design multiple drainage pipelines for each catchment area, including independently arranged rainwater pipelines and sewage pipelines;

[0008] Step B: According to the design parameters of the rainwater pipeline, the rainwater pipeline drainage capacity of each catchment area is determined;

[0009] Step C: According to the rainwater pipeline drainage capacity, the specific implementation of the rainwater pipeline is determined;

[0010] Step D: Through calculation, it is verified that the implementation of the rainwater pipeline meets the design-determined rainwater pipeline drainage capacity;

[0011] Step E: According to the design parameters of the sewage pipeline, the sewage capacity of the catchment area is calculated;

[0012] Step F: According to the sewage pipeline drainage capacity, the implementation of the sewage pipeline is determined to meet the design-integrated sewage capacity requirements of each catchment area;

[0013] Step G: Through calculation, it is verified that the implementation of the sewage pipeline of the catchment area meets the design-determined sewage pipeline drainage capacity;

[0014] The steps B-D and steps E-F can be interchanged as a whole.

[0015] By dividing the drainage area into multiple catchment areas and arranging rainwater pipelines and sewage pipelines for each catchment area, when the drainage capacity of each catchment area meets the requirements, the rainwater and sewage diversion drainage pipeline can meet the rainwater and sewage discharge requirements of the preset municipal road area;

[0016] The design method of the above rainwater and sewage diversion drainage pipeline uses a hierarchical design concept. The smallest level design ensures the drainage requirements of an area of 100-300 mu. For the drainage method of the next level, a drainage pipeline system composed of multiple catchment pipes (including rainwater pipelines and sewage pipelines) is designed. When the drainage capacity of the multiple catchment pipes meets the requirements, the drainage system within the range of 300-1000 mu can generally not have problems such as poor drainage and waterlogging.

[0017] At the same time, the design parameters of the rainwater pipeline and the design parameters of the sewage pipeline are fully considered during the design. According to the design calculation, the drainage pipeline meets the drainage requirements, and the implementation content of the rainwater pipeline and the implementation content of the sewage pipeline are determined overall. The implementation content is calculated according to the actual construction process to further verify whether the drainage capacity of the drainage area meets the design requirements and further improve the drainage capacity.

[0018] Preferably, in step B, in the design of the rainwater pipe, the design parameters of the rainwater pipe include the rainwater pipe flow rate, the rainwater pipe diameter and slope, the rainwater design return period P, the comprehensive runoff coefficient Ψ and the rainfall duration time t, wherein in the rainwater pipe flow rate, the maximum flow rate Vmax=5 m / s is taken, the flow rate Vmin=0.75 m / s is taken when full flow, in the rainwater pipe diameter and slope design parameters, the minimum pipe diameter of the connection pipe between the rainwater inlet and the rainwater inspection well is not less than DN300, the slope i is not less than 0.01, the pipe diameter of the rest part of the rainwater pipe is not less than DN800, and the slope i is not less than 0.003, the rainwater design return period P is not less than 3 years, and the comprehensive runoff coefficient Ψ is not less than 0.65.

[0019] The rainwater design return period P refers to the statistical time interval of the occurrence of the design storm intensity twice in the rainwater drainage design, the flow runoff coefficient refers to the ratio of the runoff to the rainfall in the peak flow duration, combined with the limit intensity theory, the peak flow duration corresponds to the catchment time of the catchment area, and the values of the rainwater design return period P and the flow runoff coefficient are directly related to the size of the pipe and the consumption material, thereby affecting the construction efficiency of the pipe. The larger the pipe diameter, the more the pipe consumption material, the lower the construction efficiency, and the higher the cost. The value of the rainwater design return period P is at least 3 years, and the comprehensive runoff coefficient Ψ is designed to be not less than 0.65, which can ensure the drainage capacity of the pipe, take into account the drainage capacity at the rainfall peak, and avoid excessive design and waste of the drainage capacity of the pipe.

[0020] Further, the rainfall duration time t includes the ground surface water time t1 and the pipe rainwater flow time t2, t=t1+t2, by considering the ground surface water time and the pipe rainwater flow time in the design, higher requirements are put forward for the design of the rainwater pipe, drainage is avoided due to the neglect of any one of the ground surface water or the pipe rainwater flow, and the purpose of sufficient and effective drainage is achieved.

[0021] Preferably, the rainwater pipe drainage capacity is selected according to the storm intensity q, and the storm intensity q is calculated according to the storm intensity formula ; wherein q represents the storm intensity, P represents the storm return period, the storm return period is 3 years, t represents the design rainfall duration time, which is selected according to the length of the rainwater pipe network and the size of the catchment area, t=t1+t2(min), t1 represents the ground surface water time, t2 represents the pipe rainwater flow time, t1 is taken as 15 min to 20 min, and t2 is determined according to the flow rate.

[0022] Preferably, the rainwater pipeline is designed with a pipe diameter of DN300, and the rainwater pipeline is spliced by a plurality of rainwater pipeline sections. Each rainwater pipeline section is made of a grade II reinforced concrete pipe, two adjacent pipeline sections are connected by a socket joint, and a rubber ring is used for sealing. A 180° gravel foundation is arranged at the bottom of the connection part of the rainwater pipeline section, and the connection part is reinforced by 360° full concrete wrapping. The slope of the rainwater pipeline is not less than 1%.

[0023] The design and connection mode of the rainwater pipeline section can ensure the safe operation of the rainwater pipeline, avoid damage to the rainwater pipeline at the connection part and thus prevent pipe explosion. The socket joint structure facilitates mass production of the rainwater pipeline and facilitates construction, thereby improving the construction efficiency of the rainwater pipeline. The slope of not less than 1% can ensure the flow rate of the rainwater pipeline and avoid the problem of waterlogging caused by long retention time of the water in the pipeline.

[0024] Further, when the pipe diameter of the rainwater pipeline is greater than DN2000mm, the rainwater pipeline adopts a C30 reinforced concrete box culvert, and a 10-20cm-thick C20 plain concrete cushion layer is arranged at the bottom of the box culvert. A 20-30cm-thick medium-coarse sand foundation is further arranged at the bottom of the plain concrete cushion layer.

[0025] The structure of the reinforced concrete box culvert can meet the requirements of the rainwater pipeline on the pipe diameter. The arrangement of the plain concrete cushion layer and the medium-coarse foundation from top to bottom at the bottom of the box culvert can ensure the safe installation and operation of the rainwater pipeline with the structure of the reinforced concrete box culvert, and avoid the problems of settlement and hard contact at the bottom of the box culvert, which affect the safety of the pipeline connection.

[0026] Further, the cross-sectional shape of the box culvert adopts a circular ring or a square ring structure.

[0027] For step E, the urban design comprehensive sewage quantity calculation formula is used for calculation. A plurality of design parameters of the sewage pipeline are determined according to the drainage area, including the highest daily water consumption index Qi[m³ / (hm 2 .d)] of different types of land, the scale (hm 2 ) of different types of land, the sewage discharge coefficient k1, the water supply daily variation coefficient k2, the groundwater infiltration rate k3, and the total variation coefficient of sewage quantity Kz. The urban design comprehensive sewage quantity calculation formula is Q=∑k1×Qi× k2×k3×Ai / 24 / 3600×Kz.

[0028] In this embodiment, for the drainage area, the sewage quantity is calculated by using different types of land water consumption index method, the domestic sewage quantity is 90% of the total water consumption, the industrial wastewater is 80% of the total water consumption, and the infiltration quantity of 5-30% of the groundwater is also considered, therefore, the groundwater infiltration rate k3 is 1.05-1.3, the groundwater infiltration rate k3 in this embodiment is 1.1, the city water supply daily variation coefficient k2 is 1.1-1.5, the city water supply daily variation coefficient k2 in this embodiment is 1.3, the sewage discharge coefficient k1 is 0.8 / 0.9, the sewage pipeline adopts gravity flow, and is in the form of a circular pipe non-full flow. The value of the total variation coefficient Kz of the sewage is determined according to the average daily flow (L / s) of the sewage.

[0029] The minimum design flow rate of the sewage pipeline is 0.6 m / s under the design fullness, and the maximum design flow rate is 5 m / s; when crossing the regional river, the inverted siphon is arranged, the flow rate of the inverted siphon is greater than 0.9 m / s, and is greater than the flow rate in the water inlet pipe.

[0030] In step F, when the implementation content of the sewage pipeline is determined according to the sewage discharge quantity of the sewage pipeline, the sewage pipeline flow rate is calculated according to the design slope of the sewage pipeline, the sewage flow rate is adjusted to be within the economic flow rate range, the pipe diameter is determined according to the flow rate, and the sewage pipeline sewage capacity is calculated through the sewage flow rate, the sewage pipeline slope and the fullness, so as to ensure that the designed sewage pipeline meets the sewage discharge quantity requirement of the designed sewage pipeline.

[0031] Further, the sewage pipeline flow rate calculation adopts the following calculation formula: In the formula, n is the roughness coefficient, the roughness coefficient n of the reinforced concrete pipe is 0.013, the roughness coefficient n of the plastic pipe is 0.011, and when other materials are selected as the sewage pipeline, the roughness coefficient of the rainwater pipeline needs to be adjusted and selected.

[0032] The minimum design flow rate of the sewage pipeline is 0.6 m / s under the design fullness, and the maximum design flow rate is 5 m / s; when crossing the regional river, the inverted siphon is arranged, the flow rate of the inverted siphon is greater than 0.9 m / s, and is greater than the flow rate in the water inlet pipe.

[0033] Further, by performing the above hydraulic design on the city area, the rainwater pipeline design and the sewage pipeline design are performed on the total pipeline according to the confluence pipeline of each drainage area, so that the waterlogging of the city area can be effectively avoided.

[0034] Preferably, steps B-D specifically include the following steps:

[0035] Step BD1: arranging multiple groups of drainage pipe sections in multiple catchment areas, obtaining the interval between two adjacent pipe sections in each group of pipe sections, obtaining the catchment time t1 according to the interval, determining the flow velocity v (m / s) in the rainwater pipe according to the design slope of the pipe section, and calculating the water flow time t2 in the rainwater pipe according to the flow velocity;

[0036] Step BD2: determining the catchment area F (ha) according to the interval between each pipe section and the service area of the pipe section;

[0037] Step BD3: selecting a comprehensive runoff coefficient Ψ, and obtaining the total runoff in the catchment area of each pipe section;

[0038] Step BD4: calculating the design flow of each pipe section in each rainwater pipe under the intensity of the rainstorm according to step BD1;

[0039] Step BD5: determining the pipe diameter, slope and flow velocity of each pipe section in the rainwater pipe, calculating the maximum water carrying capacity of each pipe section, and verifying whether the maximum water carrying capacity of the pipe meets the design flow requirement in step BD.

[0040] According to the size of the service area of each pipe section, the design flow value of the pipe section is determined, and the maximum water carrying capacity of the pipe is obtained through the pipe diameter, slope and flow velocity of the pipe. When the maximum water carrying capacity of the pipe meets the design flow requirement, the drainage capacity of the rainwater pipe can be guaranteed.

[0041] Further, in step BD1, when determining the water flow time t2 in the rainwater pipe according to the flow velocity calculation, the following two ways are used to determine the water flow time in the pipe: the first way is to design and calculate with twice the water flow time in the rainwater pipe; the second way is to increase the slope of the rainwater pipe, and to reduce the water flow time in the rainwater pipe by half. In this way, the water flow time in the pipe is sufficiently increased to reduce the water flow stagnation and waterlogging caused by the slowing down of water flow speed in actual use, such as the increase of water flow viscosity due to turbidity of water flow, thereby slowing down the water flow speed.

[0042] Preferably, the steps E~G specifically include the following steps:

[0043] Step EG1: arranging multiple groups of sewage pipe sections in multiple catchment areas, and determining the length and service area of the pipe in each group of pipe sections;

[0044] Step EG2: calculating the sewage flow q1 according to the specific flow q0 of each pipe section, calculating the transmission flow q2 when there is a ring-shaped pipe section, calculating the total average flow, and obtaining the sewage design flow Q1´ of each pipe section;

[0045] Step EG3: determining the slope, pipe material, and fullness of each pipe section, and separately calculating the sewage design flow Q1 of each pipe section according to the highest daily water consumption index qi of different types of land, the size ai of different types of land, and the total variation coefficient Kz;

[0046] Step EG4: determining the pipe diameter D, slope I, flow rate V, and slope height of each pipe section in the sewage pipe, and calculating the pipe water delivery capacity of each pipe section;

[0047] Step EG5: verifying and comparing the sewage design flow Q1' obtained according to the total variation coefficient Kz and the total average flow (L / s) in each pipe section of the sewage pipe with the sewage design flow Q1 of each pipe section obtained in step EG3, and verifying that the pipe water delivery capacity obtained in step EG4 meets Q1' in step EG3 and Q1 in step EG4, thereby verifying that the sewage flow requirement is met.

[0048] In step EG2, when there are ring-shaped pipe sections, the transfer flow is involved, which is the sum of the corrected flows in each ring, related to the number of rings, nodes, and pipe sections.

[0049] In summary, by adopting the above technical solutions, the present application has at least the following beneficial effects:

[0050] 1. By dividing the drainage area into multiple catchment areas and arranging rainwater pipes and sewage pipes for each catchment area, when the drainage capacity of each catchment area meets the requirements, the rainwater and sewage diversion drainage pipes can meet the rainwater and sewage discharge requirements of the preset municipal road area. At the same time, the design parameters of the rainwater pipes and the design parameters of the sewage pipes are fully considered during the design, and the drainage pipes meet the drainage requirements according to the design calculation, and the implementation content of the rainwater pipes and the implementation content of the sewage pipes are determined overall. The implementation content is measured and calculated according to the actual construction process, further verifies whether the drainage capacity of the drainage area meets the design requirements, and further improves the drainage capacity.

[0051] 2. According to the size of the service area of each pipe section of the sewage pipe, the design flow value of the pipe section is determined, and the water delivery capacity of the pipe is obtained through the pipe diameter, slope, flow rate, and slope of the pipe. When the sewage pipe water delivery capacity meets (is greater than) the sewage design flow requirement, the drainage capacity of the sewage pipe can be guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is the design flow chart of the rainwater and sewage diversion drainage pipe of the exemplary embodiment of the present application. DETAILED DESCRIPTION

[0053] The present application will be further described in conjunction with the accompanying drawings and embodiments so as to make the purpose, technical scheme and advantages of the present application more clear. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0054] With reference to Figure 1 The design method of the rain and sewage shunting drainage pipeline of the exemplary embodiment of the present application includes the following steps when designing the rain and sewage shunting drainage pipeline for a drainage area:

[0055] Step A: The drainage area is divided into multiple catchment areas, and multiple drainage pipelines are designed for each catchment area, including independently arranged rainwater pipelines and sewage pipelines;

[0056] Step B: The rainwater pipeline drainage capacity of each catchment area is determined according to multiple design parameters of the rainwater pipeline;

[0057] Step C: The specific implementation content of the rainwater pipeline is determined according to the rainwater pipeline drainage capacity;

[0058] Step D: The implementation content of the rainwater pipeline is verified to meet the design-determined rainwater pipeline drainage capacity through calculation;

[0059] Step E: The sewage capacity of the catchment area is calculated according to multiple design parameters of the sewage pipeline;

[0060] Step F: The implementation content of the sewage pipeline is determined according to the sewage pipeline drainage capacity so as to meet the design-combined sewage capacity requirement of each catchment area;

[0061] Step G: The implementation content of the sewage pipeline of the catchment area is verified to meet the design-determined sewage pipeline drainage capacity through calculation;

[0062] The steps B-D and the steps E-F can be interchanged as a whole.

[0063] In the step A, the arranged rainwater pipeline and sewage pipeline are new pipelines, and when the old network pipeline is reconstructed, the available old network pipeline should be included in the design range of the present embodiment. Before designing the drainage pipeline, the information of the existing road layout and the distribution of the underground drainage pipeline network in the construction area is obtained, and the new road design, the new rainwater pipeline design and the new sewage pipeline design are performed according to the obtained road layout and underground drainage pipeline network distribution information.

[0064] In step B, when designing the rainwater pipeline, the design parameters of the rainwater pipeline include the rainwater pipeline flow rate, the rainwater pipeline pipe diameter and slope, the rainwater design recurrence period P, the comprehensive runoff coefficient Ψ and the rainfall duration time length t, wherein, in the rainwater pipeline flow rate, the maximum flow rate Vmax=5 m / s is taken, the flow rate Vmin=0.75 m / s when full flow, in the rainwater pipeline pipe diameter and slope design parameters, the minimum pipe diameter of the rainwater inlet and the rainwater inspection well connecting pipe is not less than DN300, the slope i is not less than 0.01, the pipe diameter of the rainwater pipeline at the rest positions is not less than DN800, and the slope i is not less than 0.003, the rainwater design recurrence period P is not less than 3 years, and the comprehensive runoff coefficient Ψ is not less than 0.65.

[0065] The rainwater design recurrence period P refers to the statistical time interval of twice occurrence of the design storm intensity in the rainwater drainage design, the flow runoff coefficient refers to the ratio of the runoff to the rainfall in the peak flow duration, the peak flow duration corresponds to the catchment time of the catchment area in combination with the limit intensity theory, and the values of the rainwater design recurrence period P and the flow runoff coefficient are directly related to the size of the pipeline, the consumption material, and further affect the construction efficiency of the pipeline. The larger the diameter of the drainage pipeline is, the more the pipeline consumption material is, and the lower the construction efficiency is, and the higher the cost is. The value of the rainwater design recurrence period P is at least 3 years, and the comprehensive runoff coefficient Ψ is designed to be not less than 0.65, which can ensure the drainage capacity of the pipeline, take into account the drainage capacity at the rainfall peak, and avoid excessive design and waste of the drainage capacity of the pipeline.

[0066] Further, the rainfall duration time length t includes the ground catchment time t1 and the rainwater flow time t2 in the pipe, t=t1+t2, by considering the ground catchment time and the rainwater flow time in the pipe in the design, higher requirements are put forward for the design of the rainwater pipeline, drainage is avoided due to the neglect of any one of the rainwater on the ground or in the pipe, and the purpose of sufficient and effective drainage is achieved.

[0067] The rainwater pipeline drainage capacity is selected according to the storm intensity q, and the storm intensity q is calculated according to the storm intensity formula ; wherein, q represents the storm intensity, P represents the storm recurrence period, the storm recurrence period is 3 years, t represents the design rainfall duration time length, which is selected according to the length of the rainwater pipeline network and the size of the catchment area, t=t1+t2(min), t1 represents the ground catchment time, t2 represents the rainwater flow time in the pipe, t1 is 15 min to 20 min, and t2 is determined according to the flow rate.

[0068] The rainwater pipeline is designed with a pipe diameter of DN300, and is formed by splicing multiple rainwater pipeline sections. Each rainwater pipeline section is made of grade II reinforced concrete pipe, and the adjacent two pipeline sections are connected by a socket joint and sealed by a rubber ring. A 180° gravel foundation is arranged at the bottom of the connection part of the rainwater pipeline section, and the connection part is reinforced by 360° full concrete wrapping. The slope of the rainwater pipeline is not less than 1%. The design and connection mode of the rainwater pipeline section described above can ensure the safe operation of the rainwater pipeline, avoid damage to the rainwater pipeline at the connection part and thus prevent the occurrence of pipe burst phenomenon. The socket joint structure is convenient for mass production of rainwater pipelines and facilitates construction, thereby improving the construction efficiency of the rainwater pipeline. The slope of not less than 1% can ensure the flow rate of the rainwater pipeline and avoid the problem of waterlogging caused by long retention time of water in the pipeline.

[0069] Further, when the pipe diameter of the rainwater pipeline is > DN2000mm, the rainwater pipeline adopts a C30 reinforced concrete box culvert, and a 10-20cm thick C20 plain concrete cushion layer is laid at the bottom of the box culvert. A 20-30cm thick medium-coarse sand foundation is further arranged at the bottom of the plain concrete cushion layer.

[0070] The structure of the reinforced concrete box culvert can meet the requirements of the rainwater pipeline on the pipe diameter size, and the arrangement of the plain concrete cushion layer and the medium-coarse foundation from top to bottom at the bottom of the box culvert can ensure the installation and operation safety of the rainwater pipeline with the structure of the reinforced concrete box culvert, and avoid the problems of settlement and hard contact at the bottom of the box culvert, which affect the safety of pipeline connection.

[0071] Further, the cross-sectional shape of the box culvert adopts a circular ring or square ring structure.

[0072] In steps B-D, when the specific pipeline drainage capacity is designed, a certain catchment area is described, which is composed of three roads, named first road, second road and third road. The specific design and calculation steps and the related parameters obtained are as follows:

[0073] The plurality of pipe sections are arranged in the first road, and four pipe sections YS1-YS2, YS2-YS3, YS3-YS4 and YS4-YS5 are taken as an example. The spacing between the YS1-YS2 pipe section and the previous pipe section is 180 m, the spacing between the YS1-YS2 pipe section and the YS2-YS3 pipe section is 198 m, the spacing between the YS2-YS3 pipe section and the YS3-YS4 pipe section is 261 m, and the spacing between the YS3-YS4 pipe section and the YS4-YS5 pipe section is 237 m. The water collection time t1 of each pipe section is obtained according to the spacing of the four pipe sections. The water collection time t1 of the YS1-YS2 pipe section is 15 min, the water collection time t1 of the YS2-YS3 pipe section is 15.96 min, the water collection time t1 of the YS3-YS4 pipe section is 15 min, and the water collection time t1 of the YS4-YS5 pipe section is 15 min. The flow velocity v (m / s) in the rainwater pipeline is determined according to the design slope of the pipe section and the length of the pipe section. The value of the design slope can be selected according to the industry specification. The water flow time t2 in the rainwater pipeline is determined according to the flow velocity of each pipe section, and the water flow time t2 in the pipe of the YS1-YS2 pipe section is 0.96 min, the water flow time t2 in the pipe of the YS2-YS3 pipe section is 1.67 min, the water flow time t2 in the pipe of the YS3-YS4 pipe section is 1.95 min, and the water flow time t2 in the pipe of the YS4-YS5 pipe section is 1.77 min. The design calculation is performed at twice the water flow time in the rainwater pipeline, and the 2xt2 times of the four pipe sections are 1.93 min, 3.34 min, 3.90 min and 3.54 min, respectively.

[0074] According to the distance between the four pipe sections and the service area of the pipe sections, the increased catchment area F (ha) of the four pipe sections is: the increased catchment area F of the YS1-YS2 pipe section is 3.51, the increased catchment area F of the YS2-YS3 pipe section is 3.82, the increased catchment area F of the YS3-YS4 pipe section is 4.86, and the increased catchment area F of the YS4-YS5 pipe section is 4.56; in order to avoid calculation, it is set in the embodiment that not all of the pipe sections are new, the cumulative catchment area of the four pipe sections is equal to the increased catchment area, the comprehensive runoff coefficient Ψ of the four pipe sections is selected to be 0.65, and thus the cumulative catchment area, the total runoff and the design flow in the catchment area of each pipe section are obtained: the cumulative increased catchment area Ψ.F of the YS1-YS2 pipe section is 2.28, the design flow q of the YS1-YS2 pipe section under the intensity of the rainstorm is 302.06, the design flow of the YS1-YS2 pipe section is 689.14 (L / s.ha), the cumulative increased catchment area Ψ.F of the YS2-YS3 pipe section is 4.76, the design flow q of the YS2-YS3 pipe section under the intensity of the rainstorm is 294.28, the design flow of the YS2-YS3 pipe section is 1402.09 (L / s.ha), the cumulative increased catchment area Ψ.F of the YS3-YS4 pipe section is 3.16, the design flow q of the YS3-YS4 pipe section under the intensity of the rainstorm is 302.06, the design flow of the YS3-YS4 pipe section is 954.2 (L / s.ha), the cumulative increased catchment area Ψ.F of the YS4-YS5 pipe section is 2.96, the design flow q of the YS4-YS5 pipe section under the intensity of the rainstorm is 302.06, and the design flow of the YS4-YS5 pipe section is 895.30 (L / s.ha);

[0075] The pipe diameter, slope and flow rate of four pipe sections (pipe segments) in the rainwater pipeline are determined, and the maximum water carrying capacity of each pipe section is calculated, which are: the pipe diameter of YS1-YS2 pipe section is 0.8 m, the slope is 0.01, and the flow rate is 3.11 (M / s), after implementation according to the implementation content, the maximum water carrying capacity of YS1-YS2 pipe section is 1562.78, which is much larger than the design flow value of the pipe section, and meets the design flow requirement; the pipe diameter of YS2-YS3 pipe section is 1.0 m, the slope is 0.003, and the flow rate is 1.98 (M / s), after implementation according to the implementation content, the maximum water carrying capacity of YS2-YS3 pipe section is 1551.98, which is greater than the design flow value of the pipe section; the pipe diameter of YS3-YS4 pipe section is 1.2 m, the slope is 0.003, and the flow rate is 2.23 (M / s), after implementation according to the implementation content, the maximum water carrying capacity of YS3-YS4 pipe section is 2523.69, which is much larger than the design flow value of the pipe section; the pipe diameter of YS4-YS5 pipe section is 1.2 m, the slope is 0.003, and the flow rate is 2.23 (M / s), after implementation according to the implementation content, the maximum water carrying capacity of YS4-YS5 pipe section is 2523.69, which is much larger than the design flow value of the pipe section; therefore, each pipe section (pipe segment) meets the design flow requirement.

[0076] Similarly, a plurality of pipe sections arranged for the second road and the third road are also designed and calculated in the same way, and the design flow and hydraulic calculation table obtained are as shown in Table 1.

[0077] Table 1 Design flow and hydraulic calculation table of the remaining plurality of rainwater pipelines

[0078]

[0079] Through the design and calculation of YS5-YS6 pipe section, YS6-YS7 pipe section, YS7-YS8 pipe section, YS8-YS9 pipe section, YS9-YS10 pipe section and YS10-YS11 pipe section, it can be seen that each pipe section (pipe segment) obtained by the design method meets the design flow requirement.

[0080] In this embodiment, the design flow value of each pipe segment is determined according to the size of the service area of each pipe segment, and the maximum water carrying capacity of the pipeline is obtained through the pipe diameter, slope and flow rate of the pipeline and other parameters, and after calculation and implementation verification, when the maximum water carrying capacity of the pipeline meets the design flow requirement, the drainage capacity of the rainwater pipeline can be ensured.

[0081] When the water flow time t2 in the rainwater pipe is determined according to the flow rate calculation, another way of determining the water flow time in the pipe can also be adopted: the slope of the rainwater pipe is increased, and the water flow time in the rainwater pipe is halved. In this way, the water flow time in the pipe is sufficiently increased to reduce the water flow stagnation and waterlogging caused by the slowing down of the water flow speed in actual use, such as the increase of the water flow viscosity due to the turbidity of the water flow, thereby slowing down the water flow speed.

[0082] For step E, the urban design comprehensive sewage quantity calculation formula is adopted for calculation, and a plurality of design parameters of the sewage pipe are determined according to the drainage area, including the highest daily water consumption index Qi [m³ / (hm 2 .d)] of different types of land, the scale (hm 2 ) of different types of land, the sewage discharge coefficient k1, the water supply daily variation coefficient k2, the groundwater infiltration rate k3, and the total sewage quantity variation coefficient Kz. The urban design comprehensive sewage quantity calculation formula is Q=∑k1×Qi× k2×k3×Ai / 24 / 3600×Kz.

[0083] In this embodiment, the sewage quantity is calculated by using the water consumption index method for different types of land for the drainage area. The domestic sewage quantity is 90% of the total water consumption, and the industrial wastewater is 80% of the total water consumption. In addition, the infiltration amount of 5-30% of the groundwater is considered. Therefore, the groundwater infiltration rate k3 is 1.05-1.3, and the value taken in this embodiment is 1.1. The urban water supply daily variation coefficient k2 is 1.1-1.5, and the value taken in this embodiment is 1.3. The sewage discharge coefficient k1 is 0.8 / 0.9. The sewage pipe adopts gravity flow, and is in the form of a circular pipe with non-full flow. The fullness (h / d) of the sewage pipe is determined according to the pipe diameter or the channel height. Under the design flow, the ratio of the water depth h of the sewage / water flow in the pipe to the pipe diameter (inner diameter) D is called the design fullness. For reference, see Table 2 below.

[0084] Table 2 Maximum Design Fullness (h / d) Selection Table

[0085]

[0086] The total sewage variation coefficient kz is a commonly used parameter in urban sewage engineering design, which is used to describe the variation of sewage flow. It usually refers to the ratio of the maximum daily maximum sewage quantity to the average daily average sewage quantity in a year, that is, kz = Qmax / Qavg. Wherein, Qmax represents the maximum daily maximum sewage quantity in a year, and Qavg represents the average daily average sewage quantity.

[0087] The value of the total sewage change coefficient Kz is determined according to the average daily sewage flow (L / s) : when the average daily sewage flow (L / s) is greater than or equal to 5 L / s and less than 15 L / s, the value of Kz is 2.7; when the average daily sewage flow (L / s) is greater than or equal to 15 L / s and less than 40 L / s, the value of Kz is 2.4; when the average daily sewage flow (L / s) is greater than or equal to 40 L / s and less than 70, the value of Kz is 2.1; when the average daily sewage flow (L / s) is greater than or equal to 70 L / s and less than 100 L / s, the value of Kz is 2.0; when the average daily sewage flow (L / s) is greater than or equal to 100 L / s and less than 200 L / s, the value of Kz is 1.9; when the average daily sewage flow (L / s) is greater than or equal to 200 L / s and less than 500 L / s, the value of Kz is 1.8; when the average daily sewage flow (L / s) is greater than or equal to 500 L / s and less than 1000 L / s, the value of Kz is 2.6; when the average daily sewage flow (L / s) is greater than or equal to 10000 L / s, the value of Kz is 1.5, and the average daily sewage flow is less than 5 L / s (uninhabited area).

[0088] The water consumption indicators of different land uses are as shown in Table 3.

[0089]

[0090] Table 3 Water consumption indicators of different land uses qi[m 3 / (hm 2 ·d)]

[0091] The total sewage is obtained according to all relevant types of land and areas in the drainage area,

[0092] The minimum design flow rate of the sewage pipeline is 0.6 m / s under the design fullness, and the maximum design flow rate is 5 m / s; a inverted siphon is arranged when crossing a regional river, and the flow rate of the inverted siphon is greater than 0.9 m / s and greater than the flow rate in the water inlet pipe.

[0093] In step F, when determining the implementation content of the sewage pipeline according to the sewage pipeline drainage capacity, the sewage pipeline flow rate is calculated according to the sewage pipeline design slope, the sewage flow rate is adjusted to be within the economic flow rate range, the pipe diameter is determined according to the flow rate, and the sewage pipeline sewage capacity is calculated through the sewage flow rate, the sewage pipeline slope and the fullness, so as to ensure that the designed sewage pipeline meets the requirements of the sewage pipeline drainage capacity determined in the design.

[0094] Preferably, the sewage pipeline flow rate calculation adopts the following calculation formula: In the formula, n is the roughness coefficient, the roughness coefficient n of the reinforced concrete pipe is 0.013, the roughness coefficient n of the plastic pipe is 0.011, and when other materials are selected as the sewage pipeline, the value is selected according to the value range shown in Table 4.

[0095] Table 4 roughness coefficient value reference table

[0096]

[0097] It is worth noting that the roughness coefficient of the rainwater pipe can also be selected according to Table 4.

[0098] In steps E~G, when the specific sewage pipe drainage capacity is designed, the aforementioned catchment area is described, and a plurality of groups of sewage pipes are arranged in the catchment area composed of the first road, the second road and the third road. The specific design calculation steps and the related parameters obtained are as follows:

[0099] A plurality of sewage pipes are arranged in the first road. Two are described in the embodiment, namely WS1-WS2 and WS2-WS3. The pipe length of the WS1-WS2 pipe section is 524 m, and the service area (catchment area) of the WS1-WS2 pipe section is 8.52. Combined with the designed specific flow rate q0 of the WS1-WS2 pipe section, q0 is 1.2 (L / (s.ha)), the sewage flow rate q1 of the WS1-WS2 pipe section is calculated to be 10.22 (L / s). Since the WS1-WS2 pipe section has a ring-shaped pipe section, the transmission flow rate q2 of the WS1-WS2 pipe section is calculated to be 144.00 (L / s). Thus, the total average flow rate Q1´ is calculated to be 154.22 (L / s). The slope, pipe material and fullness of the WS1-WS2 pipe section are determined. According to the highest daily water consumption index qi of different types of land, the scale ai of different types of land and the total variation coefficient Kz, the sewage design flow rate Q1 of the WS1-WS2 pipe section is calculated to be 243.44. The implementation content of the WS1-WS2 pipe section in the sewage pipe is determined, including the pipe diameter D of 600 mm, the slope I of 0.5%, the flow rate V of 1.59 (m / s), the slope height of 2.62 m and the fullness h / d of 0.65. The pipe water conveying capacity of the WS1-WS2 pipe section is calculated to be 292.22 (L / s). Through verification and comparison, the sewage design flow rate Q1´ of the WS1-WS2 pipe section according to the total variation coefficient Kz and the total average flow rate (L / s) is 154.22. The sewage design flow rate Q1 of the WS1-WS2 pipe section is 243.44. The pipe water conveying capacity of the WS1-WS2 pipe section is 292.22 (L / s). The pipe water conveying capacity value 292.22 (L / s) is greater than Q1´ and Q1, thereby verifying that the sewage flow rate requirement is met.

[0100] The pipeline length of the WS2-WS3 pipe section is 410 m, the service area (catchment area) of the WS2-WS3 pipe section is 6.60, combined with the specific flow rate q0 of the WS2-WS3 pipe section designed, q0 is 1.2 (L / (s.ha)), the sewage flow rate q1 of the WS2-WS3 pipe section is calculated to be 7.92 (L / s), since the WS2-WS3 has a ring pipe section, the transmission flow rate q2 of the WS2-WS3 pipe section is calculated to be 168.00 (L / s) at the same time, the total average flow rate Q1' is calculated to be 175.92 (L / s), the slope, pipe material and fullness of the WS2-WS3 pipe section are determined according to the highest daily water consumption index qi of different types of land, the scale ai of different types of land and the total variation coefficient Kz, the sewage design flow rate Q1 of the WS2-WS3 pipe section is calculated to be 273.77, the implementation content of the WS2-WS3 pipe section in the sewage pipe is determined, including the pipe diameter D is 600 mm, the slope I is 4.8%, the flow rate V is 1.78 (m / s), the slope height is 19.68 m, the fullness h / d is 0.65, the pipe water conveying capacity of the WS2-WS3 pipe section is calculated to be 27.13 (L / s); by checking and comparing the sewage design flow rate Q1' of the WS2-WS3 pipe section in the sewage pipe according to the total variation coefficient Kz and the total average flow rate (L / s), the sewage design flow rate Q1 of the WS2-WS3 pipe section is 273.77, the pipe water conveying capacity of the WS2-WS3 pipe section is 327.13 (L / s), the pipe water conveying capacity value 327.13 (L / s) is greater than Q1' and Q1, thereby verifying that the sewage flow rate requirement is met;

[0101] Similarly, for the second road and the third road, the same method is also used for design and calculation, and the design flow rate and hydraulic calculation table obtained are as follows in Table 5.

[0102] Table 5 Sewage hydraulic calculation table of the remaining sewage pipe

[0103]

[0104] By respectively designing and calculating the WS3-WS4 pipe section, the WS4-WS5 pipe section, the WS5-WS6 pipe section and the WS6-WS7 pipe section, it can be seen that each pipe section (pipe section) obtained by the design method meets the sewage discharge design flow rate requirement.

[0105] The design method of the rainwater and sewage separation drainage pipe in this embodiment can also be implemented in a larger range, such as by performing hydraulic design on a city area, designing rainwater pipe and sewage pipe for the total pipe of the drainage convergence pipe in each drainage area, so that the drainage convergence pipe meets the rainwater and sewage discharge capacity in a larger range, which can effectively avoid the situation of urban area waterlogging.

[0106] The above descriptions are only specific implementation ways of the present application, not limitation to the present application. Various replacements, variations and improvements made by the skilled in the art without departing from the principles and scope of the present application should be included in the protection scope of the present application.

Claims

1. A design method of a rain and sewage separation sewer, characterized by, In the rain and sewage separation drainage pipe design of the drainage area, the following steps are included: Step A: divide the drainage area into multiple catchment areas, design multiple drainage pipes in each catchment area, including independently arranged rainwater pipes and sewage pipes; Step B: according to the multiple design parameters of the rainwater pipe, the rainwater pipe drainage capacity of each catchment area is determined; Step C: according to the rainwater pipe drainage capacity, the specific implementation content of the rainwater pipe is determined; Step D: through calculation, it is verified that the implementation content of the rainwater pipe meets the design determined rainwater pipe drainage capacity; Step E: according to the multiple design parameters of the sewage pipe, the sewage quantity of the catchment area is calculated; Step F: according to the sewage pipe drainage capacity, the implementation content of the sewage pipe is determined to meet the design comprehensive sewage quantity requirement of each catchment area; Step G: through calculation, it is verified that the implementation content of the sewage pipe of the catchment area meets the design determined sewage pipe drainage capacity; The steps B-D and steps E-F can be exchanged as a whole, wherein, In the steps B-D, the following steps are included: Step BD1: multiple groups of drainage pipe sections are designed and arranged in multiple catchment areas, and the distance between adjacent two pipe sections in each group of drainage pipe sections is obtained, and the catchment time t1 is obtained according to the distance, and the flow velocity V in the rainwater pipe is determined according to the design slope I of the drainage pipe section, unit m / s, and the flow time t2 in the rainwater pipe is calculated and determined according to the flow velocity V; Step BD2: according to the distance between each group of drainage pipe sections and the service area of the drainage pipe section, the catchment area F is determined, unit ha; Step BD3: the comprehensive runoff coefficient Ψ is selected and determined, and the total runoff in the catchment area of each group of drainage pipe sections is obtained; Step BD4: according to step BD1, the design flow of each group of rainwater pipes in each group of drainage pipe sections under the intensity of rainstorm is calculated; Step BD5: the pipe diameter D, slope I and flow velocity V of each group of drainage pipe sections in the rainwater pipe are determined, and the maximum water conveying capacity of each group of drainage pipe sections is calculated, and it is verified whether the maximum water conveying capacity of the rainwater pipe meets the design flow requirement in step BD; In the steps E-G, the following steps are included: Step EG1: multiple groups of sewage pipe sections are designed and arranged in multiple catchment areas, and the length and service area of each group of sewage pipe sections are determined; Step EG2: according to the specific flow q0 of each group of sewage pipe sections, the sewage flow q1 is calculated, when there is a ring-shaped sewage pipe section, the transmission flow q2 is also calculated, and the total average flow is calculated, and the sewage design flow Q1' of each group of sewage pipe sections is obtained; Step EG3: the slope I, pipe material and fullness of each group of sewage pipe sections are designed and determined, and the sewage design flow Q1 of each group of sewage pipe sections is calculated according to the highest daily water consumption index qi of different types of land, the scale Ai of different types of land and the total variation coefficient Kz; Step EG4: the pipe diameter D, slope I, flow velocity V and slope height implementation content of each group of sewage pipe sections in the sewage pipe are determined, and the sewage pipe conveying capacity of each group of sewage pipe sections is calculated; Step EG5: verifying and comparing the sewage design flow rate Q1' obtained from the total variation coefficient Kz and the total average flow rate (L / s) in each group of sewage pipe sections with the value of the sewage design flow rate Q1 of each group of sewage pipe sections obtained in step EG3, and verifying and determining whether the sewage pipe conveying capacity obtained in step EG4 meets Q1' in step EG2 and Q1 in step EG3, so as to verify that the sewage flow rate requirement is met.

2. The method of designing a storm sewer according to claim 1, wherein, In step B, when designing the rainwater pipe, the design parameters of the rainwater pipe include the rainwater pipe flow rate V, the rainwater pipe diameter D and the slope I, the rainwater design return period P, the comprehensive runoff coefficient Ψ and the rainfall duration t, wherein the maximum flow rate Vmax=5 m / s is taken in the rainwater pipe flow rate V, the flow rate Vmin=0.75 m / s is taken at full flow, the minimum pipe diameter D of the rainwater inlet and the rainwater inspection well connecting pipe is not less than DN300 in the rainwater pipe diameter D and the slope I design parameter, the slope I is not less than 0.01, the rainwater pipe diameter D of the rest part is not less than DN800, and the slope I is not less than 0.003, the rainwater design return period P is not less than 3 years, and the comprehensive runoff coefficient Ψ is not less than 0.

65.

3. The design method of a rain and sewage separation sewer according to claim 2, characterized by, The rainfall duration t includes the ground surface water time t1 and the in-pipe rainwater flow time t2, t=t1+2t2, and when the specific implementation of the rainwater pipe is determined in step B, t=t1+2t2.

4. The design method of a rain and sewage separation sewer according to claim 1, characterized by, In the step B, when determining the rainwater pipe drainage capacity of each catchment area, the rainwater pipe drainage capacity is selected according to the storm intensity q, and the storm intensity q is selected according to the storm intensity formula are calculated; wherein q represents the storm intensity, P represents the storm recurrence period, the storm recurrence period is 3 years, t represents the design rainfall duration, which is selected according to the length of the rainwater pipe network and the size of the catchment area, t=t1+t2 (min), t1 represents the ground water collection time, t2 represents the rainwater flow time in the pipe network, t1 is 15 min to 20 min, and t2 is determined according to the flow velocity V.

5. The method of designing a storm sewer according to claim 4, wherein, In step E, the rainwater pipe design diameter D is DN300, the rainwater pipe is spliced by a plurality of drainage pipe sections, each drainage pipe section adopts a grade II reinforced concrete pipe, a socket joint is used between adjacent two drainage pipe sections, a rubber ring is used for sealing, a 180° gravel foundation is arranged at the bottom of the drainage pipe section connection part of the rainwater pipe, and the connection part is reinforced and treated by 360° full concrete wrapping, and the slope I of the rainwater pipe is not less than 1%.

6. The method of designing a storm sewer as claimed in claim 1, wherein, In step E, the urban design comprehensive sewage quantity calculation formula is used for calculation, a plurality of design parameters of the sewage pipe are determined according to the drainage area, including the highest daily water consumption index Qi of different types of land, the scale Ai of different types of land, the sewage discharge coefficient k1, the water supply daily variation coefficient k2, the groundwater infiltration rate k3 and the total variation coefficient Kz of sewage quantity, and the urban design comprehensive sewage quantity calculation formula is Q=∑k1×Qi× k2×k3×Ai / 24 / 3600×Kz.

7. The method of designing a storm sewer according to claim 6, wherein, In step F, when the implementation content of the sewage pipe is determined according to the sewage pipe drainage capacity, the rainwater pipe flow rate V is calculated according to the design slope I of the sewage pipe, the sewage flow rate V is adjusted to be within the economic flow rate range, the pipe diameter D is determined according to the flow rate, and the sewage pipe drainage capacity is calculated through the sewage flow rate V, the sewage pipe slope I and the fullness, so that the designed sewage pipe meets the design determined sewage pipe drainage capacity requirement.

8. The method of designing a storm sewer according to claim 7, wherein, The sewage pipeline flow rate V is calculated by the following formula: ; in the formula, n is a roughness coefficient, the pipeline roughness coefficient n of the reinforced concrete pipe is 0.013, the pipeline roughness coefficient n of the plastic pipe is 0.011, when other material pipes are selected as the sewage pipeline, the roughness coefficient of the rainwater pipeline is adjusted and selected, R is a hydraulic radius, R=D / 4, I is a slope.

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