Regional flood control project embankment design method

Abstract

The invention discloses a regional flood control project embankment design method, which specifically comprises the following steps of: 1, collecting and analyzing flood control project design background data of a selected region, analyzing the engineering geology of the selected region, and designing a water level and a flow according to the current situation of the flood control project; 2, determining the flood control capacity by analyzing the current situation of a flood control project so as to arrange the scale of the flood control project; 3, main building design is conducted according to the flood control project scale arrangement, and then overall arrangement of the flood control project is achieved. The safety problem of the existing western plateau water channel embankment is solved, the flood control project embankment structure is standardized, the ecological stability is improved, and meanwhile the effective organization and coping capacity of the embankment flood situation is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy projects, and in particular relates to a method for designing a bank embankment for a regional flood control project. Background Art

[0002] In recent years, as people's requirements for living environment and quality of life have greatly increased, society has also paid more attention to the protection of water environment and water ecology. People's cognition of waterways has changed from simple survival and economic utilization to diversified needs. They pay attention to the recognition of the return of rivers as public ties, the development of waterfront environments, the construction of corridor ecological greening, and improving the interactive relationship between people and rivers. This can not only reduce the misunderstandings and regrets of development and construction, but also create a good carrier space for cities to shape rich urban culture, civic spirit, and ecological landscapes. However, the waterways in the western plateau are in disrepair for many years, the river channels are seriously silted up, residents' domestic sewage is directly discharged, and garbage is littered. As a result, the water conveyance function, flood control function, and ecological self-purification function have declined sharply. The management of the waterways in the western plateau is imminent. Summary of the invention

[0003] Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the present invention discloses a method for designing embankments of regional flood control projects.

[0004] Technical solution: The present invention provides a method for designing a regional flood control project embankment, which specifically includes the following steps:

[0005] Step 1: Collect and analyze the background information of flood control project design in the selected area, analyze the engineering geology of the selected area, and design the water level and flow according to the current status of the flood control project;

[0006] Step 2: Determine the flood control capacity by analyzing the current status of flood control projects, and thus arrange the scale of flood control projects;

[0007] Step 3: Design the main buildings according to the scale of the flood control project to achieve the overall layout of the flood control project.

[0008] Furthermore, the specific method of designing the flood frequency and peak of the flood during the design construction period is: considering the construction schedule, combining weather causes, hydrological statistical laws, and the requirement that the construction period does not affect farmland irrigation, determine the time period of the flood during the construction period, use the survey method to determine the flood frequency within the time period, use the analogy method to determine the flood within the time period, and then estimate the peak of the control section within the time period based on the ratio of the flood within the time period to the annual flood.

[0009] Furthermore, in step 1, the water level and flow rate are designed according to the current status of the flood control project as follows:

[0010] Step 1.1: Use the survey and analysis method to obtain the relationship curve between the low water level and the flow, and use the Manning formula to perform an extension calculation on the relationship between the high water level and the flow to obtain the overall relationship curve between the water level and the flow;

[0011] Step 1.2: Use the hydrodynamic model to calculate the changes of water level and flow over time and space;

[0012] Step 1.3: Based on the existing flood and related data, perform river network generalization calculation, river section calculation and relevant parameter selection. The relevant parameters include river roughness, flow boundary and starting water level. The relationship curve provided in step 1.1 is used as the flow boundary. The hydrodynamic model in step 1.2 is used to complete the calculation of water level and flow.

[0013] Furthermore, the specific method for designing the flood frequency and peak during the design and construction period is as follows: considering the construction schedule, combining weather causes, hydrological statistical laws, and the requirement that the construction period does not affect farmland irrigation, determine the time period of floods during the construction period, use the survey method to determine the flood frequency within the time period, use the analogy method to determine the flood within the time period, and then estimate the peak of the control section within the time period based on the ratio of the flood within the time period to the annual flood.

[0014] Furthermore, the engineering geology of the selected area under analysis includes evaluation of embankment foundation settlement deformation and anti-sliding stability, permeability stability, seismic stability, and river bank anti-scouring and slope stability.

[0015] Furthermore, the seismic stability evaluation includes land type evaluation, earthquake liquefaction identification and soft soil subsidence evaluation.

[0016] Furthermore, the permeability stability evaluation includes judging whether the clay layer or soft soil layer has soil flow failure and whether the silt sand layer has pipe burst failure;

[0017] Determine whether the clay layer or soft soil layer has soil flow failure:

[0018] Jcr1=(G s -1)(1-n)

[0019] Among them, Jcr1 represents the critical hydraulic drop value of clay layer or soft soil layer, G s is the specific gravity of soil particles, n is the porosity of soil; based on Jcr1, it is judged whether the clay layer or soft soil layer has soil flow failure;

[0020] Determine whether piping damage occurs in the fine sand layer:

[0021] Jcr2=2.2(G s -1)(1-n) 2 (d5 / d20)

[0022] Among them, d5 is the upper limit particle size of the sediment that accounts for 5% by weight in the total sand sample; d20 is the upper limit particle size of the sediment that accounts for 20% by weight in the total sand sample, and Jcr2 is the critical hydraulic ratio drop value of the silt sand layer. Whether the silt sand layer has pipe burst damage is determined based on Jcr2.

[0023] Furthermore, the flood control capability in step 2 includes analyzing existing flood control safety issues and calculating the current water surface line.

[0024] Furthermore, the scale of the flood control project layout includes the layout of flood control embankments, the layout of buildings through the embankments and the layout of drainage projects.

[0025] Furthermore, in the layout of the flood control embankment, a slope protection type combining concrete lattice beams and interlocking prefabricated blocks is used for the embankment sections where the bank slope is unstable and the river channel width is less than a preset threshold.

[0026] Furthermore, the main building design includes the embankment top elevation design, embankment section design, embankment stability calculation, water-facing slope protection design, embankment-through building design, retaining wall stability stress calculation and embankment foundation treatment; the embankment top elevation design is performed according to the following formula:

[0027] Y=R+e+A

[0028] Among them, Y represents the super height of the dike top, R is the wave climbing height, e is the height of water increase due to wind, and A is the safety height increase; the Putian Experiment Station formula is used to determine the average wave height and thus the wave climbing height;

[0029] The following formula is used to design the slope protection on the water-facing side:

[0030]

[0031]

[0032] Where t is the thickness of the block or stone armor layer; n is the number of armor blocks or stone layers; c is the coefficient, Q is the individual mass of the armor blocks in the main armor layer; γ b is the weight of the masonry blocks, γ is the weight of water; H is the wave height; K D is the stability coefficient.

[0033] Beneficial effects: The present invention designs flood flow and engineering geological problems according to the current status of the flood control project embankment and background information, and then conducts comprehensive remediation of the flood control project, ensuring that the trajectory and mainstream line of the flood are analyzed in combination with the original terrain and the current status of the embankment, so as to meet the needs of scientific and natural embankment project layout; the present invention implements the principle of adapting measures to local conditions and using local materials, actively and scientifically adopts new technologies, new processes, and new materials to ensure that the embankment line layout is combined with urban planning requirements as much as possible without affecting the safety of the flood control embankment, so as to achieve the ecological restoration and landscape development needs of the embankment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the present invention;

[0035] Figure 2 The present water surface line of the flood of Laopanjiang River in 20 years;

[0036] Figure 3 The water level-flow relationship curve of the West Bridge Station of the present invention;

[0037] Figure 4 It is a typical cross-sectional view of the flood control project embankment of the present invention;

[0038] Figure 5 A typical cross-sectional diagram (K5+100) calculated for the present invention;

[0039] Figure 6 Typical cross-sectional diagram calculated for the present invention (K17+750);

[0040] Figure 7 This is a schematic diagram for comparing the embankment lines of the river section with pile numbers 0+300 to 0+800;

[0041] Figure 8 This is a schematic diagram of the embankment line selection for the river section with pile numbers 0+300 to 0+800. DETAILED DESCRIPTION

[0042] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0043] like Figure 1 As shown, a regional flood control project embankment design method provided by the present invention can be implemented by the following technical solutions:

[0044] Step 1: Collect and analyze the background information of flood control project design in the selected area, and design flood flow and engineering geological issues according to the current status of flood control projects;

[0045] Step 2: Analyze the flood control capacity and arrange the scale of flood control projects based on the current status of flood control projects; the flood control capacity analysis includes analyzing the existing problems of flood control safety and calculating the current water surface line; the scale of flood control projects includes the layout of flood control embankments, the layout of buildings through embankments and the layout of drainage projects;

[0046] Step 3: Design the main buildings according to the scale of the flood control project to achieve the overall layout of the flood control project.

[0047] The flood flow design step in step 1 includes:

[0048] S1. Design the flood volume of the selected area according to the flood investigation method and Manning formula, develop a water level-flow relationship curve and obtain preset data;

[0049] S2. Calculate using the hydrodynamic module (HD) equation of MIKE11 according to the preset data:

[0050] Continuity equation:

[0051] Momentum equation:

[0052] Where: Z is the average water level of the section (m); Q is the flow rate of the section (m3 / s); A is the water area (m2); B is the width of the water surface (m); x and t represent the distance (m) and time (s) respectively; q is the lateral inflow, and a negative value represents outflow; β is the momentum correction coefficient; g is the acceleration of gravity (m / s2); S f is the friction slope, calculated using the Manning formula, S f =g / C 2 , C=h 1 / 6 / n;u l It is the component of the lateral outflow velocity in the mainstream direction on the unit flow.

[0053] S3. Based on the existing flood and related data, the river network is roughly calculated, the river section is calculated and the relevant parameters are selected to complete the water level design.

[0054] The analysis of engineering geological problems in step 1 includes: evaluation of embankment foundation settlement deformation and anti-sliding stability, evaluation of seepage stability, evaluation of seismic stability, river bank anti-scouring and bank slope issues.

[0055] Among them, the evaluation of seepage stability issues is carried out by stratifying the soil layers:

[0056] (a) Clay layer or soft soil layer (Q 1-1 ):

[0057] Clay or soft soil layers are commonly distributed in riverbanks and lower foundations. The clay content is greater than 35%, and the form of seepage failure is soil flow. The formula is now used to calculate the critical hydraulic gradient Jcr1 of the soil layer; compare it with the actual hydraulic gradient J to determine whether soil flow failure occurs:

[0058] Jcr=(G s _1)(1_n)

[0059] Where: G s is the specific gravity of soil particles; n is the porosity of soil.

[0060] (ii) Fine sand layer (Q 1-3 ):

[0061] This layer is mainly composed of fine sand and has a clay content of 15.4%. To determine whether pipe burst damage occurs, the critical hydraulic gradient Jcr2 of this layer is calculated according to the following formula:

[0062] Jcr2=2.2(G s _1)(1-n) 2 (d5 / d20)

[0063] Where: d5 is the upper limit particle size of the sediment that accounts for 5% by weight in the total sand sample; d20 is the upper limit particle size of the sediment that accounts for 20% by weight in the total sand sample.

[0064] Among them, the evaluation of seismic stability issues includes site category evaluation, earthquake liquefaction identification, and soft soil subsidence evaluation.

[0065] Preferably, the main building design in step three includes: embankment top elevation design, embankment section design, embankment stability calculation, water-facing slope protection calculation, embankment-through building design, retaining wall stability stress calculation, and embankment foundation treatment.

[0066] Preferably, the dike top elevation design includes:

[0067] 1) Calculation formula for super height of embankment top:

[0068] Y=R+e+A

[0069] In the formula: Y is the super height of the embankment top (m); R is the designed wave climb (m); e is the designed wind-induced water increase height (m); A is the safety height increase (m), and the value for level 4 embankment is 0.6m.

[0070] 2) Wave element calculation formula:

[0071]

[0072] Where: H is the average wave height (m); T is the average wave period (s); V is the calculated wind speed (m / s); F is the length of the wind zone (m); d is the average water depth of the water area (m); g is the gravitational acceleration (9.81m / s 2 );t min It is the minimum wind time (s) for wind and waves to reach a stable state.

[0073] 3) Calculation formula of Fengyong water surface height

[0074] When the water level of Fengyong is in a limited wind zone, it can be calculated according to the formula in the Code for Design of Embankment Engineering (GB50286-2013):

[0075]

[0076] Where: e is the height of the wind-proof water surface at the calculation point (m); K is the comprehensive friction coefficient, which can be taken as K = 3.6 × 10 -6 ; V is the design wind speed, which is determined by the wind speed of the calculated waves; F is the distance from the upwind vector of the calculation point to the opposite bank (m); d is the average water depth of the water area (m); β is the angle between the wind direction and the normal perpendicular to the axis of the embankment (°).

[0077] 4) Wave height calculation formula:

[0078] When the slope gradient is 1.5 ≤ m ≤ 5, the wave height can be calculated as follows:

[0079]

[0080] Where: R p is the wave height with cumulative frequency p (m); K △ is the roughness and permeability coefficient of the slope; K v is the empirical coefficient; Kp is the cumulative frequency conversion coefficient of climbing height; m is the slope rate, m = ctg rate, α is the slope angle (°); H is the average wave height of the waves in front of the embankment (m); R0 is the smooth and impermeable protective surface in the absence of wind (K △ =1) Climbing height value (m) when H=1m.

[0081] The embankment section design includes embankment structure design, slope protection design, embankment top pavement design and river step design.

[0082] The calculation of the water-facing slope protection adopts the following formula:

[0083]

[0084]

[0085] Where: t is the thickness of the block or stone armor layer (m); n is the number of armor blocks or stone layers; c is the coefficient; Q is the individual mass of the armor block of the main armor layer (t); γ b is the weight of the masonry block (kN / m 3 ); γ is the density of water (kN / m 3 );H is the design wave height (m); K D is the stability coefficient.

[0086] The overall layout of the flood control project in step three includes: general plan layout, embankment line selection, foot protection type selection, slope protection type selection, embankment building layout, and drainage project layout.

[0087] This example uses Xinpanjiang River, Laopanjiang River and Yanfang River as selected areas, where the range of Xinpanjiang River is from Gucheng Gate to Xiqiao, the range of Laopanjiang River is the entire river section (Gucheng Gate to the estuary of Xinpanjiang River), and the range of Yanfang River is from Dazui Village Water Gate to the estuary of Xinpanjiang River. Xiqiao Hydrological Station is located in Xiqiao Village, Zhongshu Town, Luliang County, and flow measurement is carried out using a current meter.

[0088] Distribution of survey lines: river width 20m~60m, 7~13 survey lines above the middle water level, one-point and two-point methods are used for velocity measurement; 7~9 survey lines below the middle water level, three-point method is used for velocity measurement. The zero height of the water gauge is generally calibrated before and after the flood season, and no changes have been found. Sediment observation began in July 1959, and sediment is measured on the survey ship using a horizontal sampler. From 1957 to the present, precipitation is observed using a self-recording rain gauge; the water level-flow relationship is a single line each year; the extension amplitude of high water is less than 5%, and the extension amplitude of low water is less than 20%; about 400m downstream of the section, beach blasting is often carried out, and the flood discharge capacity of the river channel has been gradually increased over the years; this section is relatively stable, and there are slight changes in scouring and silting at high water levels.

[0089] The average runoff depth of the Laopanjiang River Basin is 300 mm, the runoff variation coefficient Cv = 0.40, Cs = 2Cv; the average runoff volume of the Laopanjiang River Basin is 23.935 million m 3 The design flood calculation of Laopanjiang River is planned to adopt the method of flood calculation based on rainstorm and flood investigation to investigate Laopanjiang River. The design flood of Laopanjiang River with a return period of 20 years is calculated by flood calculation based on rainstorm and the result is 134.9m 3 / s, the survey value is 123m 3 / s, the difference between the two is within 10%. Since the survey value is a historical measurement and the recurrence period is once in 20 years, the design flood of Laopanjiang River in this embodiment adopts the survey value of 123m 3 / s.

[0090] like Figure 2 As shown, the steps for designing the flooding of the selected area in this embodiment are specifically as follows:

[0091] Design flood

[0092] 1) Lao Panjiang

[0093] The geographical parameters of Laopanjiang were calculated using the 2014 1:10000 topographic map.

[0094] The design flood calculation for Laopanjiang River is planned to adopt the method of inferring floods from heavy rains and flood investigation.

[0095] (1) Heavy rains leading to floods

[0096] According to the center position of the catchment area of ​​each control section of Laopanjiang River, the "Statistical Parameter Map of Heavy Rainfall in Yunnan Province" (2007 Edition) was checked to obtain the 1, 6, and 24-hour point heavy rain of Laopanjiang River, and the average precipitation of each duration was obtained. Cv.

[0097] The center of the catchment area of ​​each control section of Laopanjiang River is located in the 12th rainstorm zone, the 2nd runoff zone, and the 2nd confluence zone. The maximum soil moisture content (W m ) and water content before rain (W t ) are 100mm and 78mm respectively, stable permeability (f c ) is 2.5mm, the basin unbalanced water volume (△R) is 10mm; the confluence coefficient C m , C n They are 0.40 and 0.80 respectively.

[0098] The designed net rainfall process and instantaneous unit line of the Laopanjiang River basin can be deduced from the characteristic parameters and runoff coefficient of the basin, and then the designed flood process line and the corresponding flood peak can be calculated.

[0099] (2) Flood survey values

[0100] When the Laopan River flooded in July 1997, the flood survey value of Xinba Sluice was 123m 3 / s, the Yunnan Provincial Hydrological Bureau determined through comprehensive analysis of relevant data that the July 1997 flood recurrence period was once in 20 years. 2 , Laopanjiang P=5% frequency design flood can adopt the Xinba Gate flood survey value of 123m 3 / s.

[0101] (3) Adoption of results and rationality analysis

[0102] The design flood of Laopanjiang River in 20 years is calculated by heavy rain and the flood calculation result is 134.9m 3 / s, the survey value is 123m 3 / s, the difference between the two is within 10%. Since the survey value is a historical measured occurrence and the recurrence period is analyzed to be once in 20 years, the survey value of 123m / s is used for the design flood of Laopanjiang this time. 3 / s.

[0103] The flood peak modulus of the survey value is 1.54, and the flood peak modulus of Yanfang River is 1.38. Since Yanfang River and Laopanjiang are both located on the left bank of Xinpanjiang River in Luliang Dam area, the underlying surface and hydrological and meteorological conditions are similar, and the flood peak modulus is similar by comparison. Therefore, the design flood results of Laopanjiang are reasonable. The design flood of each control section of Laopanjiang is calculated according to the area analogy method (the area ratio index is 2 / 3). According to the measured data and relevant data of Xiqiao and Zhanyi hydrological stations, the coefficient of variation Cv refers to the hydrological station and takes into account the basin area and underlying surface conditions, and is taken as 0.5, Cs = 4Cv.

[0104] 2) Xinpanjiang

[0105] The design flood of Xinpanjiang River adopts the peak flow calculation results of "Preliminary Design Report on the Regulation Project of Luliang Section of Nanpanjiang River in Qujing City, Yunnan Province".

[0106] 3) Yan Fanghe

[0107] The design flood of Yanfang River was verified using the method of inferring floods from heavy rains. After verification, the results were almost the same as the design flood in the Preliminary Design Report on the Yanfang River Control Project in Luliang County, Yunnan Province.

[0108] 4) Dugong River and Weibai River

[0109] Dugong River and Weibai River are both tributaries of Yanfang River, with catchment areas of 30.7 and 30.0 km respectively. 2 According to the peak modulus of the design flood of Yanfang River, which is 1.38, the peak results of the design flood of Dugong River and Weibai River with a return period of once in 20 years are calculated.

[0110] Construction period flooding

[0111] The Laopanjiang River Basin has a northern subtropical plateau monsoon climate, with a rainy season from mid-May to late October, and major floods from June to September. Taking into account the construction schedule, combined with weather causes, hydrological statistics, and that the construction period does not affect farmland irrigation, the construction period is determined to be the dry season from December to April of the following year. The flood during the construction period is a once-in-five-year standard.

[0112] The dry season flood in the Laopanjiang River Basin cannot be inferred from measured data. According to the actual situation of the basin, the "analogy method" is used to calculate the dry season flood. The ratio of dry season flood to annual flood in the "Banqiao River Control Project Preliminary Design Report" approved by the Yunnan Provincial Water Resources Department and implemented is used to estimate the dry season flood in the control section. The Banqiao River dry season flood accounts for 0.056. According to calculations, the Laopanjiang River dry season flood with a return period of 5 years is 4.5m 3 / s.

[0113] When dry season floods are used in construction design, rainfall and water condition monitoring and reporting should be strengthened during construction, and the scheduling of upstream reservoirs and river gates should be strengthened to ensure the safety of construction during the flood season.

[0114] The specific steps for designing the flood flow of the selected area in this embodiment are:

[0115] S1. When the Laopanjiang River flooded in July 1997, the flood survey value of Xinba Sluice was 123m 3 / s, and through comprehensive analysis of relevant data, it was determined that the recurrence period of the flood in July 1997 was once in 20 years. 2 , Laopanjiang P=5% frequency design flood can adopt the Xinba Gate flood survey value of 123m 3 / s.

[0116] S2: Using the measured low water level-flow relationship data from the "2016 Xiqiao Station Water Level-Flow Relationship Table", the Manning formula is used to perform an extension calculation of the high water level-flow relationship. The resulting water level-flow relationship curve is as follows: Figure 3 As shown in Figure 1, the Manning formula is an empirical formula used to calculate the relationship between water level and flow in an open channel. Its mathematical expression is as follows:

[0117] Q=(1 / n)×A×R 23 ×S 12

[0118] Among them, Q is the flow rate (in cubic meters per second), A is the cross-sectional area (in square meters), R is the ratio of the wetted perimeter to the cross-sectional area, S is the slope of the water surface, and n is the Manning roughness coefficient.

[0119] S3. The hydrodynamic model is calculated using the hydrodynamic module (HD) of MIKE11.

[0120] S4. Based on the existing flood and related data, the river network is roughly calculated, the river section is calculated and the relevant parameters are selected to complete the water level design.

[0121] Step S4 is specifically as follows: The calculation scope of river network generalization includes: establishing a water network model to calculate the water surface line. According to the data, the lower boundary of the model is the Xiqiao hydrological station section of the main stream of Xinpanjiang River. The calculation scope includes the river section from 2km above the Xinpanjiang Ancient City Gate to the Xiqiao hydrological station, Laopanjiang River, Yanfang River, Dugong River, and Weibai River. The statistical parameters of each river are shown in Table 1.

[0122] Table 1

[0123] river Calculate river length (km) Slope(‰) Average river width (m) Xinpanjiang 20.88 0.36 81.1 Laopanjiang 18.78 0.40 64.9 Yan Fanghe 17.45 0.41 78.1 Dugong River 13.88 0.20 24.9 Dugong River Branch 3.08 0.57 22.7 Wei Baihe 7.87 0.17 26.8

[0124] Cross-river buildings: The cross-river buildings on the Laopanjiang River are mainly sluice gates and bridge projects.

[0125] Water gate projects: The water gate projects within the calculation range of the Laopanjiang water surface line in this embodiment include Gucheng Water Gate, Shagou Water Gate, Xinba Water Gate, Sihe Water Gate (Luchang Water Gate), and Guansheng Palace Water Gate. The scale of each water gate project is shown in Table 2.

[0126] Table 2

[0127]

[0128] Bridge projects: There are 11 bridge projects in Laopanshang, mainly beam bridges. The basic information of each bridge project is shown in Table 3.

[0129] Table 3

[0130] Serial number Mileage(m) Bridge deck elevation (m) Clear span(m) Remark 1 903 1837.8 55.7 Black Bridge 2 5868 1834.6 20.1 3 6569 1834.8 22.2 4 6991 1835.3 22.7 5 7837 1835.3 20.8 6 9051 1835.8 46.6 Zhoudong Bridge 7 10903 1834.5 20.6 8 11877 1835.6 43.4 9 13380 1834.0 32.7 10 14396 1833.8 21.0 Panxinqiao 11 17499 1834.1 79.2 Yangjiaqiao

[0131] Among them, the large-section data of the river channel adopts the measured sections in 2018, and the sections are arranged by comprehensively considering factors such as river channel boundaries, mutation points in the river channel, locations of hydraulic structures, and tributary confluence points. The statistics of each river channel section are shown in Table 4.

[0132] Table 4

[0133] river River length (km) Number of sections Section interval (m) Xinpanjiang 20.88 51 500 Laopanjiang 18.78 82 250 Yan Fanghe 17.45 60 300 Dugong River 13.88 29 1000 Dugong River Branch 3.08 7 1000 Wei Baihe 7.87 13 1000

[0134] The relevant parameters include: river channel roughness, flow boundary, and starting water level;

[0135] (1) The roughness of the river channel is mainly selected based on the Hydraulic Design Manual (Second Edition) and the existing design materials of the river channel, namely, the Preliminary Design Report of the Luliang Section of the Nanpanjiang River Regulation Project in Qujing City, Yunnan Province, the Preliminary Design Report of the Laopanjiang River Regulation Project in Luliang County, Yunnan Province, and the Preliminary Design Report of the Yanfang River Regulation Project in Luliang County, Yunnan Province. The roughness of the Xinpanjiang River is 0.023 according to the project rate, the roughness of the Laopanjiang River is 0.0275, the roughness of the Yanfang River is 0.027, and the roughness of the Dugong River and Weibai River are 0.03.

[0136] (2) The flow boundary is determined by the length and direction of the river to determine the flow boundary of the hydrodynamic model; the model flow boundary adopts the above-mentioned flood design results.

[0137] (3) The starting water level is based on the “Preliminary Design Report on the Regulation Project of the Nanpanjiang River in Luliang, Qujing City, Yunnan Province”. The peak flow rate of the Xiqiao hydrological station section once in 20 years is 707m 3 / s, combined with the water level-flow relationship of Xiqiao Hydrological Station, the design water level of Xiqiao Hydrological Station for a return period of 20 years is 1831.849m. The starting water levels of each design frequency are shown in Table 5.

[0138] Table 5

[0139]

[0140] The dispatching rules of the sluice project during flood season include diverting floodwaters from Xinpanjiang River to Laopanjiang River through Gucheng sluice and diverting floodwaters from Laopanjiang River to Dugong River.

[0141] (1) When a flood of 30-years or less occurs in Xinpanjiang River, the Gucheng Sluice Gate will be closed;

[0142] (2) When a flood of 20-years or less occurs in the Laopan River, the Guanshenggong Gate will be closed;

[0143] (3) During flood season, Shagou Sluice Gate, Xinba Sluice Gate and Sihe Sluice Gate are all opened to discharge water.

[0144] Taking into account the most unfavorable situation for flood discharge, the floods of Laopanjiang and Xinpanjiang are both designed floods that return once every 20 years. The calculated water level and flow results of each typical control section are shown in Table 6 below.

[0145] Table 6

[0146]

[0147]

[0148] As an embodiment of the present invention, the analysis of engineering geological problems in step 1 includes:

[0149] The main engineering geological problems are analyzed, including: evaluation of embankment foundation settlement deformation and anti-sliding stability, evaluation of seepage stability, evaluation of seismic stability, river bank anti-scouring and slope stability.

[0150] The evaluation of seismic stability issues includes site category evaluation, earthquake liquefaction identification, and soft soil subsidence evaluation.

[0151] According to the 1:4 million "China Earthquake Motion Parameter Zoning Map" (GB18306-2015), the peak acceleration of the earthquake motion with a probability of exceeding 10% in 50 years in the project area is 0.15g, the characteristic period of the earthquake motion response spectrum is 0.45s, and the corresponding basic earthquake intensity is VII degrees; the project area is located in the Nanpanjiang River system, and the two banks are plateau canyons and plateau mountains and small basins. The groundwater is completely replenished by atmospheric precipitation infiltration, which is conducive to atmospheric precipitation infiltration and replenishment. The surface runoff is weak, and the groundwater is discharged from the watershed to the Yongqing River Basin or Basin. The lithology of the survey area is mainly clastic rock, and the other is the Quaternary loose accumulation layer. The groundwater type is mainly weathered fissure water in the northwest, and fissure water in the southeast near the entrance of the Nanpanjiang River, with a small amount of karst water. The project area of ​​this embodiment is mainly located in alluvial and lacustrine areas, and the groundwater type is mainly overburden pore water. Through the general analysis of the geology of this region, we know the geological conditions and evaluation of Laopanjiang and Yanfanghe. The geological conditions of Laopanjiang are as follows: Laopanjiang is located in the belly of Luliang Basin and runs through Luliang Basin. The terrain is flat, with an altitude of 1810-1840m, which belongs to plain landform.

[0152] Laopanjiang River is located in the center of Luliang Basin and runs through it. It is flat with an altitude of 1810-1840m and belongs to plain landform. The terrain on both sides of the river is flat with a slope of less than 5 degrees. There are no adverse physical geological phenomena such as landslides and large collapse bodies. However, due to water erosion and human damage, there are also a few landslides on the local riverbanks.

[0153] Yanfang River is located in the southeast of Luliang Basin, and its main stream originates from Dalongtan Mountain Spring. In addition to the task of runoff irrigation and flood discharge in this area, it also undertakes the flood diversion and water diversion irrigation functions of Laopanjiang River. The terrain is open and flat, with an altitude of 1836-1825m. The river valley is wide and flat, and the river channel area is located in the hinterland of the southern Luliang Basin, which is a plain landform. There are no adverse physical geological phenomena such as landslides and large collapse bodies.

[0154] (1) Evaluation of embankment foundation subsidence deformation and anti-sliding stability

[0155] The upper part of the embankment foundation in the project area is all Quaternary lake sedimentary layers, and the lower part is Quaternary alluvial layers. The soft soil layer is continuously distributed and has a large thickness. It is in a saturated, fluid-plastic-soft-plastic state. It has a large water content, high compressibility, low shear strength, and a long consolidation time. The anti-sliding stability of the thickened and filled embankment foundation in the soft soil zone and the uneven settlement of the new and old embankments are the main engineering geological problems of this embodiment.

[0156] a) Anti-slip stability

[0157] The surface bearing layer of the embankment foundation contains silt, muddy soil and fine sand, which is thick and weak, affecting the stability of the embankment foundation. The soft soil has low shear strength and a small friction coefficient with the embankment and building foundations. Underwater ground excavation can easily expose the surface clay soil, resulting in sandy soil and silt exposure, which is not conducive to the anti-sliding stability of the embankment slope.

[0158] b) Settlement deformation

[0159] There is soft soil distributed in all sections of the project area, and the soft soil layer is relatively thick, generally 0.9m to 5.6m. The soft soil has not yet completed self-weight consolidation. After the embankment is raised, it is inevitable that the embankment foundation will undergo slow and long-term settlement under the load. The final settlement depends on the scale of embankment raising. The thickness of the soft soil along the embankment line is uneven, and the range of change in some sections is large. There will be obvious uneven settlement between sections or between new and old embankments.

[0160] In summary, the embankment foundation of this embodiment has problems of sinking, deformation, and anti-sliding stability, and uneven settlement occurs between embankment sections.

[0161] (2) Evaluation of penetration stability issues

[0162] In the selected area of ​​this embodiment, there are medium to strong permeable silt-sand and fine sand layers. The sand layers are shallowly buried and are prone to leakage and permeability deformation when the water level is high. Therefore, the leakage and permeability stability problems of shallowly buried sand are also the main engineering geological problems of this project.

[0163] The silt-sand or fine sand layer in the embankment foundation of the project area has strong permeability, shallow burial, and a layer thickness of generally 0.9 to 5.6 m; silty clay and clay are mainly distributed on the surface, with continuous distribution, a thickness of generally 3.0 m to 11.0 m, weak water permeability, and is a relatively impermeable layer, forming a stable impermeable roof.

[0164] The stratigraphic structure of the riverbank is mainly composed of alternating deposition of clay layers, soft soil layers and fine sand layers. Sometimes it is a transition phase, such as the silt-sand layer, which is the transition phase between the silt layer and the fine sand layer. According to the "Specifications for Geological Survey of Water Conservancy and Hydropower Engineering" (GB50487-2008), the stratification judgment is as follows:

[0165] (a) Clay layer or soft soil layer (Q l-1 ):

[0166] Clay or soft soil layers are commonly distributed in riverbanks and lower foundations. The clay content is greater than 35%, and the form of seepage failure is soil flow. Calculate the critical hydraulic gradient Jcr1 of the soil layer. In this embodiment, Jcr1 = (2.73-1)(1-0.884) = 0.20, and the actual hydraulic gradient is: J = 2.0 / 20 = 0.1; Jcr>J; indicating that soil flow failure is not likely to occur.

[0167] (ii) Fine sand layer (Q l-3 ):

[0168] This layer is mainly composed of fine sand and has a clay content of 15.4%. Piping damage may occur. In this embodiment, the critical hydraulic gradient Jcr2 of the fine sand layer is calculated, Jcr2 = 2.2*(2.81-1)(1-0.387) 2 (0.001 / 0.1)=0.15, the actual hydraulic gradient of this embodiment is: J=2.0 / 20=0.1, Jcr2>J; which means that pipe burst damage is not likely to occur.

[0169] (3) Evaluation of seismic stability issues

[0170] In the engineering area of ​​this embodiment, there are Q4 sand layers and soft soil layers in the embankment foundation. The two soil layers are shallowly buried (<15m), thick, stably distributed, and wide in range, and are located below the groundwater level. The basic earthquake intensity of the site is VII, which belongs to a strong earthquake zone, and the seismic stability of the embankment foundation and the building foundation needs to be considered.

[0171] a) Site Category Evaluation

[0172] According to the building site categories listed in Article 4.1.6 of the Code for Seismic Design of Buildings (GB50011-2010), the site categories can be divided into four categories based on the equivalent shear wave velocity of the soil layer and the thickness of the site cover layer. The specific conditions are divided according to the conditions listed in the following table:

[0173] Table 7

[0174]

[0175] In the table, Vs represents the shear wave velocity of rock.

[0176] According to the provisions of the Code for Seismic Design of Buildings (GB50011-2010), combined with the geological conditions of this survey and the experience of similar projects near the project area, the construction site category is determined to be Class III. Therefore, this site is an unfavorable area for building seismic resistance.

[0177] b) Earthquake liquefaction identification

[0178] 1) Preliminary judgment

[0179] There are Q4 sand layers and soft soil layers in the foundation of the project area. The two soil layers are shallowly buried (<15m), thick, stably distributed, and wide in range. They are also below the groundwater level. The basic earthquake intensity of the site is VII, which belongs to a strong earthquake zone. It is necessary to evaluate the seismic liquefaction of the foundation soil layer.

[0180] The mechanism of foundation soil liquefaction is that the coarser the soil particles, the greater the permeability, the easier it is for the pore water pressure to dissipate, and therefore it is not easy to liquefy; the finer the soil particles, the greater the adhesion, the less likely the soil particles are to disperse, and therefore it is not easy to liquefy. The particle range of easily liquefied soil is between the above two.

[0181] There is a silty sand layer 10m below the riverbank foundation, in which the clay content (<0.005mm) is 9.2%, which is less than 17% for an earthquake intensity 7 zone. It is initially judged that liquefaction may occur.

[0182] 2) Retrial

[0183] According to the review of the standard penetration data, the standard penetration point is selected in the medium and fine sand layer containing silt below the elevation of 1824.5m. This layer is located below the groundwater level, has the least clay content, and is the standard penetration point with the greatest possibility of earthquake liquefaction. Boreholes zk7~zk8. Standard penetration hammer number N 63.5 =12.8~19.2 hits, take 12.8 hits. According to the formula:

[0184]

[0185] Where: the depth of the standard inertia point ds = 10.5 ~ 12.5m, take 12.5m. The depth of the groundwater level in normal operation dw = 2.0m, the mass percentage of clay content ρc = 14.9%, and the benchmark value is taken according to the VII degree remote earthquake protection condition N o = 8 hits, calculate the critical value N cr =5.2 hits, N 63.5 =6.8 hits>N cr , and it was re-judged that there was no earthquake liquefaction problem in this layer.

[0186] c) Evaluation of soft soil settlement

[0187] Soft soil mainly refers to silt mixed with sand and silty soil. Silt mixed with sand and silty soil are exposed within the site, which is generally saturated, soft and plastic to fluid. Soft soil has the characteristics of high water content, poor permeability, low strength, high compressibility, and high sensitivity. Under the action of earthquake, the soil structure is easily damaged, and the shear strength and bearing capacity are greatly reduced, which may cause earthquake subsidence.

[0188] (4) Riverbank erosion resistance and slope stability issues

[0189] If the front slope of the embankment section is protected by a bund platform or shoal, there is generally no problem with the scouring resistance and stability of the slope. If the front slope of the embankment section lacks the bund platform or shoal protection, and the flow pattern is complex and changeable due to the influence of the width of the river channel, the river bank will be severely eroded at the turning point, forming a deep trough and forcing the bank, causing the slope to retreat continuously. Anti-scouring measures should be taken for the river bank. It is recommended to take stone throwing or stabilizing measures at the foot of the slope of the Laopanjiang River.

[0190] The main building designs in this embodiment include: embankment top elevation design, embankment section design, embankment stability calculation, water-facing slope protection calculation, embankment-through building design, retaining wall stability stress calculation, and embankment foundation treatment.

[0191] As an embodiment of the present invention, when calculating the wave elements in the design of the levee top elevation, the maximum wind speed of the Laopanjiang River over the years is 10.0m / s, the wind direction is SW, and the average wind speed over the years is only 2.8m / s. After comprehensive consideration, according to the earth-rock dam design specification, the wind speed is calculated using 1.5 times the average maximum wind speed over the years, and the procedure in this embodiment is 15m / s; since the perimeter of the opposite bank of the river is relatively regular, the maximum length of the wind zone is the widest part of the river, and the average is 100m; for levees that do not allow overtopping, the cumulative frequency of climbing is 2%, and for levees that allow overtopping, the cumulative frequency of climbing is 13%. The calculation results are shown in Table 8:

[0192] Table 8

[0193]

[0194] In this embodiment, the cross-section design of the embankment includes the embankment structure design, the bank slope protection design, the embankment top road surface design and the river step design.

[0195] Embankment structure design: Geological survey data show that the strata along the river are mainly clay, silt, and fine sand, with some areas containing silty clay and some bank slopes collapsed. According to the current status of the Laopanjiang River, full use is made of existing materials to ensure that when repairing the embankments on both sides, house demolition and occupation of arable land are minimized while meeting flood control requirements.

[0196] This project is a comprehensive river channel improvement project. The focus is on creating an ecological and cultural landscape belt on both sides of the Laopan River. The construction of flood control projects needs to be closely integrated with landscape projects and ecological projects. Most of the Laopan River is wide, with a large flood discharge section, and there are certain beaches on the banks. At present, the embankments on both sides are basically homogeneous earth embankments. Therefore, the earth embankment type is still used for embankment heightening and widening.

[0197] When filling the dikes on both sides of Laopanjiang River, for the dike sections with insufficient dike top elevation, clay soil is used to increase height and width, and the designed dike top width is 3m-6m. For the dike sections with wider river channels, when the dike height is insufficient and needs to be filled, the side slopes on both sides adopt a gentle slope of 1:3, and for the dike sections with narrower river channels, the bank slope adopts a slope of about 1:2.

[0198] In spacious river sections, the beach is wide and can be combined with landscape layout. The embankment type adopts a composite embankment type, and low retaining walls are used to make the bank slope into a multi-level composite section type. The height of the retaining wall is generally 1 to 1.5 meters to meet the functional requirements of safety, ecology, landscape and other aspects.

[0199] The embankment is filled with clay soil, which is required to be free of plant roots, bricks, tiles, garbage and other debris, with small deformation under water, plasticity index of 7-20, and the allowable deviation between the soil moisture content and the optimal moisture content is ±3%. According to the "Embankment Engineering Design Code", the embankment level of this project is level 4, and the compaction degree of the earth embankment should not be less than 0.91.

[0200] Slope protection design: According to the slope protection type selection, the 1:3 gentle slope of this project mainly adopts turf slope protection. Before the protection, the base surface should be thoroughly cleaned, and dead trees and debris on the foundation should be removed. Planting soil is laid at the bottom of the turf slope protection to facilitate the early growth of plants.

[0201] In the embankment section with steeper bank slope and narrower river channel, the bank slope is 1:2, and concrete frame beam + grass-planting type interlocking prefabricated blocks are used for slope protection. The spacing between frame beams is 3m×3m, and the thickness of interlocking prefabricated blocks is 0.15m. It can maintain the aesthetics of the bank protection and protect the stability of the bank slope.

[0202] The river channel has been silted up for many years, and some of the steeper sections of the bank slope have a lot of silt extending to the river channel. Therefore, riprap is used at the foot of the slope to prevent scouring and stabilize the foot of the slope. In order to make the bank slope hydrophilic, the upper part of the riprap is made of masonry as the base of the slope protection. At the same time, it can be combined with landscape layout and transformation to serve as a hydrophilic platform, making the bank slope more hydrophilic. The platform is exposed 0.5m above the normal water level, 1.5m wide and 0.8m thick.

[0203] Design of the embankment top road surface: The embankment top road surface is designed based on the current situation and combined with the landscape function zoning. Most embankment sections are 6m wide, while the width of the embankment top of some sections is 3m wide due to site limitations.

[0204] The road surface is made of cement concrete with a thickness of 0.2m, and the lower part is paved with a gravel base with a thickness of 0.2m. Some landscape node pavements can be combined with landscape layout and use colored concrete pavement.

[0205] Typical cross-sectional structural types of Laopanjiang flood control project are as follows: Figure 4 , Figure 5 ,as well as Figure 6As shown in the figure, the design of the steps down to the river: some steps down to the river are set up along the dikes on both sides of the Laopan River. People can walk along the steps from the top of the dike to the waterside waterfront platform. The steps are distributed along the river bank and arranged according to actual needs. The initial interval is 200m. Various styles can be adopted to make subtle changes along the entire river regulation landscape project, which is conducive to avoiding excessive continuity and monotony of the landscape belt. The steps can be made of C25 concrete with a thickness of 0.2m, and a crushed stone base is set at the bottom. The height-to-width ratio is designed according to the slope.

[0206] In this embodiment, when calculating the slope protection of the water-facing surface, the slope protection of the steeper section of the bank slope is selected for calculation. The thickness of the block or stone surface protection layer is 0.102m; according to the material and construction requirements, 0.15m is taken. The weight of the stone block is taken as the comprehensive weight of 20kN / m 3 ; The water density is 10kN / m 3 The wave height is taken as the wave height with a cumulative frequency of 5% H5% = 0.152m.

[0207] The overall layout of the flood control project in this embodiment includes: general plan layout, embankment line selection, foot protection type selection, slope protection type selection, embankment-through building layout, and drainage project layout.

[0208] The starting point of the comprehensive improvement project of the Laopanjiang River is Gucheng Gate, the water diversion point from Xinpanjiang to Laopanjiang, and the end point is Luchang Bridge, where the end of Laopanjiang River meets Xinpanjiang River. The total length of the improved river is about 18.8km.

[0209] In this embodiment, the river sections 0+000~18+800 are basically fertile fields and houses on both sides, with relatively concentrated houses. Most of the cultivated land is national basic farmland, and the land should be occupied as little as possible without relocation. The plane morphology of each section of the Laopanjiang River is relatively stable, and most of the embankments on both sides have met the flood control standards. Therefore, according to the actual terrain and river conditions, while ensuring the flood discharge section, the embankment lines of each river section are basically maintained in the current direction.

[0210] Based on the overall trend of the current river channel, the feasibility of local embankment line adjustment is studied.

[0211] 1) River section with pile number 0+300~0+800

[0212] like Figure 7 As shown in the figure, the river forms an almost 90° turn here. The bend can be straightened appropriately and the dike line can be adjusted to the right to make the river smoother. Widening the river will increase the landscape area of ​​the island in the river and create a better landscape effect. The dike line adjustment requires additional land acquisition, but the cultivated land on the right bank of the river is basic farmland and is not allowed to be occupied in principle. Therefore, the existing dike line layout of this section of the river is still maintained.

[0213] 2) River section with pile number 4+900~5+150

[0214] like Figure 8 As shown in the figure, this section of the river is located between the downstream of Shagou Gate and Panxin Village. This section of the river is wide, with wide beaches on both sides of the river. The original embankment is a combination of embankment and road. In recent years, with the development of the local economy and society, the villagers' self-built houses have basically occupied the beach on the right bank. After the house foundation is backfilled, the beach elevation is mostly higher than the designed flood control level of the river, but the embankment top elevation does not meet the requirements of the specification, and the bank slope needs to be reinforced.

[0215] In order to meet the flood control requirements of the river embankment and combine the landscape project layout, the embankment line of this section of the river is planned to be adjusted to the water side of the beach, and arranged along the shore as much as possible to occupy less flood-carrying section of the river. The embankment line adjustment section is about 250m.

[0216] According to the selection of dike lines, the Laopanjiang River regulation this time takes the river centerline as the axis, and the axis direction is consistent with the existing river channel. The dike lines on both sides are arranged along the existing dike road as much as possible. Only the 4+900~5+150 sections are adjusted this time, and the rest are maintained in the original dike line layout.

[0217] The basic forms of embankment selection include vertical retaining wall type, slope type, composite type, etc. This embodiment adopts the vertical retaining wall type for densely populated and narrow river sections; other wide river sections adopt the slope earth embankment type, or a composite embankment type that combines the two to meet the functional requirements of safety, ecology, landscape, etc.

[0218] Selection of foot protection type: The bank slope foot protection can be made of riprap, precast concrete blocks, retaining walls and reinforced gabions. After analysis and comparison, the river channel in this embodiment is shallow and the bank slope is gentle, so riprap foot protection can be used. In order to increase the stability and hydrophilicity of the river bank slope, block stone protection is used on the top surface of the riprap, and the stone platform is 1.5m wide.

[0219] Slope protection type selection: Currently, the commonly used slope protection types include turf planting, concrete frame beam + interlocking prefabricated bricks, ecological concrete slope protection, mortar stone slope protection, etc., each with its own advantages and disadvantages. The focus is on creating an ecological and cultural landscape belt on both sides of the Laopanjiang River, so the ecological aesthetics of the slope protection is relatively high. According to the characteristics of the embankments on both sides of the Laopanjiang River, the slope of the bank above the stone platform is about 1:2~1:3, and the bank slope of most river sections is relatively gentle, with only some sections being steeper. After the completion of the New Panjiang River, it will assume the main flood control function in the area. The Laopanjiang River will be less affected by floods, and most of the river channels are relatively wide, so the degree of flood erosion is relatively light.

[0220] Based on the above considerations, the slope protection type selected in this stage is mainly turf slope protection. Concrete frame beams + interlocking prefabricated blocks are used in the embankment sections where the local slopes are steeper and the river channels are narrower. This not only maintains the aesthetics of the bank protection, but also protects the stability of the slope.

[0221] Arrangement of buildings through the dike: The area near Baita Village on the left bank of the Laopanjiang River in this project is the intersection of the original Laopanjiang ancient river channel upstream. The dikes on both sides of the river regulation project need to keep the water flowing smoothly during the construction, and the comprehensive regulation of the Laopanjiang River needs to maintain the connectivity of the road surface on the top of the dike. Therefore, a box culvert through the dike is arranged here as a flow passage. The elevation of both sides of the ancient river channel upstream is relatively high, and no additional protection is required. There are some drainage culverts on both sides of the Laopanjiang River. Combined with the landscape project and the sewage collection and treatment projects on both sides, they will be demolished or retained as needed. When some of them need to be rebuilt, concrete circular culverts will still be used for restoration.

[0222] Layout of drainage works: The fields on both sides of the river are generally higher than the annual water level of the river, and slightly lower in some sections, but there are many culverts along the line; there are multiple pumping stations along the bank to solve the problem of waterlogging, which has met the drainage requirements. Combined with the layout of the river bank and the drainage ditch conditions at the foot of the existing outer embankment, the drainage ditch destroyed by the river bank construction is restored and rebuilt, and the water is discharged into the drainage outlet through the drainage ditch, and then discharged into the river.

[0223] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for designing a bank of a regional flood control project, characterized in that: The specific steps include: Step 1: Collect and analyze the background information of flood control engineering design in the selected area, analyze the engineering geology of the selected area, and design floods; the floods include flood frequency, flood peak, water level and flow; Step 2: Determine the flood control capacity by analyzing the current status of flood control projects, and thus arrange the scale of flood control projects; Step 3: Design the main buildings according to the scale of the flood control project to achieve the overall layout of the flood control project.

2. A regional flood control project embankment design method according to claim 1, characterized in that: The design water level and flow in step 1 are as follows: Step 1.1: Use the survey and analysis method to obtain the relationship curve between the low water level and the flow, and use the Manning formula to perform an extension calculation on the relationship between the high water level and the flow to obtain the overall relationship curve between the water level and the flow; Step 1.2: Use the hydrodynamic model to calculate the changes of water level and flow over time and space; Step 1.3: Based on the existing flood and related data, perform river network generalization calculation, river section calculation and relevant parameter selection. The relevant parameters include river roughness, flow boundary and starting water level. The relationship curve provided in step 1.1 is used as the flow boundary. The hydrodynamic model in step 1.2 is used to complete the calculation of water level and flow.

3. A regional flood control project embankment design method according to claim 1, characterized in that: The specific method for designing flood frequency and peak during the design construction period is as follows: considering the construction schedule, combining weather causes, hydrological statistical laws, and the requirement that the construction period does not affect farmland irrigation, determine the time period of flood during the construction period, use the survey method to determine the flood frequency within this time period, use the analogy method to determine the flood within this time period, and then estimate the peak of the control section within this time period based on the ratio of the flood within the time period to the annual flood.

4. A regional flood control project embankment design method according to claim 1, characterized in that: The engineering geology of the selected area for analysis includes evaluation of embankment foundation settlement deformation and anti-sliding stability, seepage stability, seismic stability, and river bank anti-scouring and slope stability.

5. A regional flood control project embankment design method according to claim 4, characterized in that: The seismic stability evaluation includes site category evaluation, earthquake liquefaction identification and soft soil subsidence evaluation.

6. A method for designing a regional flood control project embankment according to claim 4, characterized in that: The permeability stability evaluation includes judging whether the clay layer or soft soil layer has soil flow failure and whether the silt sand layer has pipe burst failure; Determine whether soil flow failure occurs in clay layer or soft soil layer: Jcr1=(G s -1)(1-n) Among them, Jcr1 represents the critical hydraulic drop value of clay layer or soft soil layer, G s is the specific gravity of soil particles, n is the porosity of soil; based on Jcr1, it is judged whether the clay layer or soft soil layer has soil flow failure; Determine whether piping damage occurs in the fine sand layer: Jcr2=2.2(G s -1)(1-n) 2 (d5 / d20) Among them, d5 is the upper limit particle size of the sediment that accounts for 5% by weight in the total sand sample; d20 is the upper limit particle size of the sediment that accounts for 20% by weight in the total sand sample, and Jcr2 is the critical hydraulic ratio drop value of the silt sand layer. Whether the silt sand layer has pipe burst damage is determined based on Jcr2.

7. A regional flood control project embankment design method according to claim 1, characterized in that: The flood control capability in step 2 includes analyzing existing flood control safety issues and calculating the current water surface line.

8. A regional flood control project embankment design method according to claim 1, characterized in that: The scale of the flood control project layout includes the layout of flood control embankments, the layout of buildings through the embankments and the layout of drainage projects.

9. A method for designing a regional flood control project embankment according to claim 8, characterized in that: In the layout of flood control embankments, for embankment sections with unstable bank slopes and river channel widths less than a preset threshold, a slope protection type combining concrete frame beams and interlocking prefabricated blocks is used.

10. A regional flood control project embankment design method according to claim 1, characterized in that: The main building design includes the embankment top elevation design, embankment section design, embankment stability calculation, water-facing slope protection design, embankment-through building design, retaining wall stability stress calculation and embankment foundation treatment; the embankment top elevation design is carried out according to the following formula: Y=R+e+A Among them, Y represents the super height of the dike top, R is the wave climbing height, e is the height of water increase due to wind, and A is the safety height increase; the Putian Experiment Station formula is used to determine the average wave height and thus the wave climbing height; The following formula is used to design the slope protection on the water-facing side: Where t is the thickness of the block or stone armor layer; n is the number of armor blocks or stone layers; c is the coefficient, Q is the individual mass of the armor blocks in the main armor layer; γ b is the weight of the masonry blocks, γ is the weight of water; H is the wave height; K D is the stability coefficient.

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