Fish blocking process design and implementation method

Abstract

The invention discloses a fish blocking process design and an implementation method, and belongs to the technical field of water conservancy projects. The method has the advantages of comprehensive consideration of environmental factors, strong guidance, high scientificity and the like, is suitable for different practical application environments, can better adapt to complex water flow conditions and fish behaviors, and reduces the influence on the ecological environment. The corresponding fish blocking process construction method is easy and convenient to operate, the construction scheme provided by the fish blocking process design method can be efficiently completed, and the requirements of factors such as water diversion engineering and ecological friendliness are met.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy engineering, and in particular to a fish intercepting process design and an implementation method. Background Art

[0002] After the completion of the water diversion project, water will be diverted from the water source area all year round. Fish resources will flow into the water diversion main canal through the head gate with the water. In order to protect the fishery resources in the water source area, fish interception facilities need to be installed at the head of the canal. This is mainly reflected in the following technical requirements: (1) Preventing fish from escaping. In water conservancy projects, the head of the water inlet needs to effectively prevent fish from escaping with the water flow to protect aquatic biological resources and avoid adverse effects on the downstream ecology; (2) Ensuring water quality safety: Through fish interception facilities, the impact of fish and their excrement on water quality can be reduced or avoided, ensuring the safety of water quality; (3) Adapting to water flow conditions: The fish interception facilities at the head of the water inlet need to be able to adapt to different water flow conditions, including water flow speed, flow rate, etc., to ensure their stability and effectiveness.

[0003] With the continuous development of water conservancy engineering technology, the fish interception technology at the head of the water inlet channel has also gone through a process from simple to complex, and from inefficient to efficient. Early fish interception facilities may be simple fences or nets, which are difficult to effectively cope with complex water flow conditions and fish behavior. With the advancement of science and technology, modern fish interception facilities use more advanced materials and designs, such as high-strength nylon nets, metal fish interception fences, etc., which greatly improve the fish interception effect and service life.

[0004] The following types of fish interception technologies are currently available in this field: (1) Nylon fish interception: It has a large filtration area, low water resistance, easy material acquisition, low cost, and simple installation. It is suitable for large and small reservoirs and spillways. When installing a nylon fish interception net at the spillway, you can first pour a row of cement columns at a certain interval or use angle irons as supports, and then hang the nylon net with thick iron wire as the upper and lower rails; (2) Metal fish fence: It has a strong structure, good durability, and good fish interception effect, but the cost is relatively high and requires regular maintenance and cleaning. It is suitable for places with fast water flow and large fish. Metal fish fences are generally made of steel bars, angle irons or wire mesh, and are installed in wooden frames or iron frames to form a movable grid; (3) Electric fence fish interception: It has high fish interception efficiency, low maintenance cost, and protects the ecological environment. , by setting up an electric field in the water body to drive or intercept fish; (4) Bamboo foil fish interception: It has a simple structure, low cost and easy management, but the fish interception effect is greatly affected by the water flow speed and fish behavior. It is mainly used at the outlet of mountain ponds and the spillway of small reservoirs. It is formed by splitting nanmu bamboo into foil and weaving it into bamboo curtains to form fish interception facilities.

[0005] For example, the Chinese invention patent with publication number CN103329834A provides a floating fish-blocking fence suitable for large-scale water diversion channels, whose structure includes a floating line, a net and a bottom line, the floating line is connected to the top of the net, the bottom line is connected to the bottom of the net, and anchor seats for fixing to both sides of the floating line are arranged at both ends; the floating line includes a steel cable and a plurality of buoys arranged along the steel cable, the steel cable and the buoys are connected by a clamp, the steel cable is arranged under the buoy, and the net is connected to the steel cable. The invention solves the problems of the existing fish-blocking nets that the net is easy to shrink during use, the mesh structure is unstable, and the water flow has a continuous impact on the net in the water diversion project through the above design. However, in actual applications, when faced with complex water flow conditions, the hydrological conditions of the fish-blocking facilities at the head of the water inlet channel are mainly controlled by the reservoir in the water source area, and this scheme cannot accurately determine the water level for blocking fish. In addition, there is a lack of corresponding design guidance for the relationship between the stability of the fish-blocking device and the bank slope at the head of the channel, and the degree of compliance with the operation and scheduling requirements of the head of the channel.

[0006] Based on the continuous progress of science and technology, the improvement of environmental awareness, and the implementation of a large number of water resource allocation projects, especially cross-basin water diversion projects, the fish interception technology at the head of the water inlet channel pays more and more attention to eco-friendliness. Facilities and technologies with good design and guidance can better adapt to complex water flow conditions and fish behavior, while reducing the impact on the ecological environment. Therefore, combining the actual situation of water diversion projects, scientifically constructing the design and implementation methods of fish interception technology has positive significance for meeting the needs of water diversion projects and eco-friendliness. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, in a first aspect of the present invention, a method for designing a fish intercepting process is provided, which takes environmental factors into consideration, has strong guidance and is highly scientific, and comprises the following steps: (1) Determine the type and specifications of fish interceptors and construct a fish interceptor system at the headwater of the water diversion project; the fish interceptor facilities of the headwater fish interceptor system include a force-bearing structure, a main body, a floating fence, and an anchor seat; (2) The force-bearing structure of the fish-blocking facility is a steel rope. Force calculations are performed to determine the structure and length of the steel rope; (3) The main body of the fish interception facility is the fish interception net, and the shrinkage coefficient and mesh size of the net must be determined; (4) Determine the method of fixing the floating boom of the fish intercepting facility and conduct stress analysis on the anchor seat; complete the design of the fish intercepting technology.

[0008] Preferably, in step (1), the fish species intercepted are dominant species determined based on the annual survey of abundant, average and scarce fishery resources; the statistical parameters of the intercepted fish size include body length ( L ),weight( W ).

[0009] Further preferably, the fish species intercepted are mainly juvenile fish.

[0010] Preferably, in step (1), a certain safety distance is reserved between the fish intercepting facility and the water inlet of the headworks building, and the safety distance is 1.8-2.0 times the width of the headworks section.

[0011] Preferably, in step (2), the steel rope is dragged by the channel water flow ( w ) drifts downstream in a parabolic shape, causing the steel rope to produce maximum axial tension ( P ), and evenly dispersedly transmitted to the anchor seats on both sides, the forces on the steel rope and the anchor seats are analyzed and calculated accordingly; The calculation formula of the drag force generated by channel water flow on fish interception facilities is as follows: w =( ρ / 2 g ) C d · A · V 2 ; in, ρ is the bulk density of water, 1.0 t / m 3 ; g is the acceleration due to gravity, 9.81 m / s 2 ; C d is the drag coefficient, which takes a value of 2.0; A is the channel water blocking area, m 2 / m; V is the channel water velocity, m / s; The calculation formula for the maximum axial tension that the steel rope can withstand is as follows: P = wl ·[1+ l 2 / 4 m 2 ] -2 ; in, l 1 / 2 of the channel width, m; m is the deformation width under the wire rope dragging state, m.

[0012] Further preferably, the hanging length of the steel rope is greater than the length of the river bottom below the anchor seat elevation, according to the deformation width ( m ) calculates and adjusts its length.

[0013] During the design, the correct selection and calculation of mesh size is related to the fish interception efficiency, fish interception composition, rational use and protection of fishery resources, investment cost and service life of fish interception facilities, etc.

[0014] Preferably, in step (3), the mesh size (a) is calculated based on the body shape coefficient of the fish, which includes the body length coefficient (k1) and the weight coefficient (k2) of the fish, and the calculation formula is as follows: a = k1·L or k2· W -b ; in, a is the mesh size, cm; L is the body length of the fish, cm; W is the body length of the fish, g; b is a constant, which is a parameter of the relationship between fish length and weight, and its value range is 2.5-3.5; The fish body coefficient is calculated based on the circumference of the intercepted part of the fish body (C), the ratio of the mesh circumference (4a) to the circumference of the intercepted part of the fish body, and the calculation formulas of the body length coefficient (k1) and the weight coefficient (k2) are as follows: c = 4a / C; k1=(c / 4)·(C / L); k2=(c / 4)·(C / W -b ); Where C is the circumference of the intercepted part of the fish body, cm.

[0015] Further preferably, the value range of the body length coefficient (k1) is 0.12-0.21; the value range of the body weight coefficient (k2) is 4.13-6.54.

[0016] Preferably, in step (3), the mesh sizes of different water layers are set according to the water level at the head of the canal and in combination with the ecological habits of fish inhabiting the upper, middle and bottom layers.

[0017] According to the application requirements of the present invention, the transverse contraction coefficient of the four major carps is 0.45-0.52, and the longitudinal contraction coefficient is 0.85-0.90; the transverse contraction coefficient of carp and crucian carp is 0.40-0.48, and the longitudinal contraction coefficient is 0.87-0.92; the transverse contraction coefficient of Culter albus is 0.55, and the longitudinal contraction coefficient is 0.82. This is used as the design basis of the contraction coefficient.

[0018] Preferably, in step (3), the unfolded view of the net is trapezoidal, with the net material being thick at both ends and thin in the middle; the open shape of the net mesh is similar to and slightly smaller than the shape of the cross-section of the fish bone; the shrinkage coefficient includes transverse and longitudinal shrinkage coefficients, the transverse shrinkage coefficient is 0.40-0.57, and the longitudinal shrinkage coefficient is 0.82-0.92.

[0019] Preferably, in step (3), the fish intercepting specifications of the net are 10%, 25%, 50%, 75%, and 90% of the frequency of the fish body length; wherein a frequency of 10% represents that the intercepted juvenile fish are large in size, a frequency of 25% represents that the intercepted juvenile fish are relatively large in size, a frequency of 50% represents that the intercepted juvenile fish are of average size, a frequency of 75% represents that the intercepted juvenile fish are relatively small in size, and a frequency of 90% represents that the intercepted juvenile fish are relatively small in size.

[0020] Taking into account that the fish intercepting net will form an arc shape due to the action of water flow after actual installation, its manufacturing size should take into account the increment brought by the deformation in order to achieve a better interception effect.

[0021] Preferably, in step (3), the actual production height and length of the fish blocking net are increased by 10%-20% compared with the design dimensions.

[0022] Preferably, in step (4), the floating grid is vertically sunk to the bottom by means of a counterweight and horizontally anchored by means of a cross-traction method.

[0023] Preferably, in step (4), considering the floating bulk density, the deadweight of the anchor seat ( G ') The friction force generated ( F ) is greater than the mooring force of the fish net; the calculation formula for the friction force generated by the deadweight of the anchor is as follows: F = f · G '; in, f is the friction coefficient; G ' is the deadweight of the anchor considering the buoyancy density, kN.

[0024] According to the actual application of the present invention, the friction coefficient is determined based on concrete and foundation silty clay.

[0025] Further preferably, the friction coefficient ranges from 0.3 to 0.45.

[0026] In a second aspect of the present invention, a method for implementing a fish interception process is provided, comprising the following steps: S1. Based on the engineering scheme determined by the fish interception process design method of the first aspect of the present invention, prepare the components of the corresponding water inlet channel headwork fish interception system and carry out field construction; S2. Before setting up the fish blocking net, clean the base of the net and ensure that the net is sunk to the bottom; S3, fix the two ends of the fish blocking net on the anchor seats on both sides, separate the upper and lower wires out of the water, and use the weight to temporarily position and shape them; then hang the main weight at the intersection of each longitudinal wire and the main weight; S4. After the main ballast is tied, the floating boom is tied to the buoy network; the anchor rope is tied at the junction of the buoy network and the longitudinal force network, connected to the anchor, and the pull rope is tied to the anchor rope; the anchor rope and the pull rope on the longitudinal force network are pulled to make the intercepting net form an arch, and then the anchor is dropped, the fish intercepting net is fixed, and the float is tied.

[0027] In order to extend the service life of fish interception facilities, good management and maintenance work must be done. Regular inspections should be carried out in the water to check whether there are gaps between the main cable rope, floating fence, and the line with weight rings and the bottom of the reservoir, whether the net is damaged or buried by mud and sand, whether the weight parts have fallen off, whether the weight rings (blocks) are sufficient, etc., and problems should be dealt with in time. During floods, personnel should be organized to check fish interception and pollution interception nets, reinforce fish interception nets, and remove floating objects in front of pollution interception nets. Pay attention to prevent the upper part of the fish interception net from being aged due to long-term exposure to sunlight. When the water level in the reservoir drops, the fish interception net should be lowered accordingly, and the exposed part of the net after the water level drops should be adjusted, and damage should be repaired in time.

[0028] When used, it is recommended that the floating gate material be ultra-high molecular weight high-density polyethylene (HMWHDPE) and add corresponding chemical additives such as antistatic agents, antioxidants, and anti-ultraviolet agents, so that the material has good weather resistance and ultraviolet (UV) resistance, and the service life under normal working conditions is ≥15 years; the maintenance and repair costs are low, and it is convenient to disassemble and assemble. The upper surface of the floating gate body adopts a non-slip pattern design or a partially arc-shaped blunt-angle reinforced rib shape, which is safe and stable. Cold and hot temperature resistance: cold and frost resistance ≤-50℃, high temperature resistance ≥50℃ (floating gate does not deform). In addition, the use and maintenance of the floating gate should follow the safe use range: the channel surface wind and wave within 2-3 levels is the safe use range; the channel surface wind and wave 3-5 levels can be used normally, but the condition of the facilities must be paid attention to; the channel surface wind and wave 5-7 levels are the extreme use conditions, and inspections must be strengthened to deal with damaged facilities in a timely manner.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention provides a method for designing a fish intercepting process. The method has the advantages of comprehensive consideration of environmental factors, strong guidance, and high scientificity. The method is suitable for different practical application environments, can better adapt to complex water flow conditions and fish behaviors, and reduce the impact on the ecological environment.

[0030] The present invention provides a fish intercepting process construction method, which is easy to operate and can efficiently complete the construction plan provided by the fish intercepting process design method of the present invention, thereby meeting the requirements of water diversion and regulation projects and ecological friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1This is a schematic diagram of the steel rope of the fish-blocking facility being subjected to uniform drag force; Figure 2 It is a schematic diagram of the PE rope, buoyancy of the buoy, and the stress of the anchor block; Figure 3 is a schematic diagram of a steel rope clamp; Figure 4 Schematic diagram of the buoy fixture. DETAILED DESCRIPTION

[0032] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0033] The steps for the fish interception process design method of this project are as follows: (1) First, investigate the fish resources in the water source area and determine the types and sizes of fish to be intercepted in the water diversion channel; conduct a year-round survey of fishery resources during the wet, medium and dry seasons to determine the dominant species as the intercepted fish; the statistical parameters of the intercepted fish size include body length ( L ),weight( W ); The intercepted fish species are mainly juveniles, and the 10%, 25%, 50%, 75%, and 90% frequencies of fish body length are taken as the fish interception specifications; among them, a frequency of 10% represents that the intercepted juveniles are large in size, a frequency of 25% represents that the intercepted juveniles are large in size, a frequency of 50% represents that the intercepted juveniles are medium in size, a frequency of 75% represents that the intercepted juveniles are small in size, and a frequency of 90% represents that the intercepted juveniles are small in size; Construct a fish interception system at the head of the water inlet channel of the water diversion project; the fish interception facilities of the fish interception system at the head of the water inlet channel include a force-bearing structure, a main body, a floating fence, and an anchor seat; in the design, a safety distance of 1.8 to 2.0 times the width of the head section is reserved between the fish interception facilities and the water inlet of the headworks; (2) The load-bearing structure of the fish interception facility is a steel rope, such as Figure 1 As shown in the figure, the steel rope drifts downstream in a parabola shape with the drag force of the water flow, so that the steel rope produces the maximum tension and is evenly distributed and transmitted to the anchor seats on both sides; Based on the specific gravity of water, gravitational acceleration, drag coefficient of the project, channel water blocking area, and channel water flow velocity, the formula ( w =( ρ / 2 g ) C d · A · V 2) calculates the dragging force of the channel water flow on the fish intercepting facility. The force on the steel rope is proportional to the square of the water velocity and the water blocking area. Combined with the dragging force, half channel width, and the deformation width of the steel rope under the dragging state, when the steel rope is subjected to uniform dragging force, the maximum axial tension borne by the steel rope can also be obtained by the formula ( P = wl ·[1+ l 2 / 4 m 2 ] -2 ) is calculated; In order to prevent the steel rope from hanging in the air at low water level, the hanging length of the steel rope is designed to be greater than the length of the river bottom below the anchor seat elevation; therefore, the deformed width parameter of the steel rope in the dragging state in the above formula can be used to calculate and adjust its length; Based on the above calculation principles, in the specific engineering design, the steel rope position is set according to the site plan, about 100 m away from the axis of the new gate at the head of Taocha Canal; the length of the fish interception facility section from the river bottom below the elevation of 170 m is about 298 m, and the distance between the anchor seats on both sides is about 288.8 m; the deformation width under the steel rope dragging state is adjusted to 40 m, and the required steel rope length can be calculated to be about 312.3 m, the tangent angle of the steel rope tension at the end point of the anchor seat is 31.03°, and the actual steel rope length is taken as 315 m; Table 1 presents the length of the steel rope and the end point rotation angle under different steel rope dragging conditions, which are used as reference values ​​for adjustment; Table 1: Steel rope length and end point rotation angle

[0034] The steel rope is mainly subjected to the drag force caused by the water flow, and its strength is determined by the interception area and the flow velocity. The flow velocity is deduced from the diversion flow rate. The flow velocity deduced according to the diversion flow rate at various water levels is shown in Table 2. Table 2: Derivation of flow rate from diversion flow at various water levels

[0035] The average design velocity is 0.66 m / s, and considering the possible errors in hydraulic calculation and topographic measurement, 1.3 times the average velocity is used as the design velocity; considering the water blocking height as the river section, the average depth is 14.72 m 2 / m; (3) The main body of the fish interception facility is the fish interception net. Determine the shrinkage coefficient of the net and correctly select and calculate the mesh size ( a ), which is related to the efficiency of fish interception, the composition of fish interception, the rational use and protection of fishery resources, the investment cost and service life of fish interception facilities, etc.; Based on the statistical results of fish body length and weight, the mesh size can be calculated according to the formula (k1·L or k2 W -b ) Determined; Combined with the calculation formula of body length coefficient and weight coefficient, through the measurement of common fish, it can be known that k1 is 0.12-0.21 and k2 is 4.13-6.54; The fish intercepting net uses a mesh size of 2.3 cm × 2.3 cm, and the thickness of the fish intercepting net wire is 2 mm; weights, piles, etc. are used to maintain the shape of the net when setting up the fish intercepting net. The unfolded view of the net is trapezoidal, with thicker mesh materials at both ends and thinner in the middle; in order to accurately determine the shrinkage coefficient of the intercepting net, the open shape of the net must be similar to and slightly smaller than the shape of the cross-section of the fish body; according to statistics, the transverse shrinkage coefficient of the four major carps is 0.45-0.52, and the longitudinal shrinkage coefficient is 0.85-0.90; the transverse shrinkage coefficient of carp and crucian carp is 0.40-0.48, and the longitudinal shrinkage coefficient is 0.87-0.92; the transverse shrinkage coefficient of Culex bream is 0.55, and the longitudinal shrinkage coefficient is 0.82; in summary, the transverse shrinkage coefficient is 0.40-0.57, and the longitudinal shrinkage coefficient is 0.82-0.92; in addition, the production height and length of the fish intercepting net should be increased by 10%-20% compared with the actual measured mesh; (4) The floating fence is vertically anchored by a bottom layer of φ 20 mm stainless steel weighted chain and horizontally anchored by cross-pulling of steel cables from anchor seats on both sides; Based on the mesh and thickness of the fish intercepting net, and considering that the water blocking rate is 30% (17% of the fishing net area + 13% of the mesh area is blocked by other objects), and considering that the sudden impact force exceeds the design, 1.5 times of the calculated maximum drag force is used as the design drag force; the steel rope is designed with 19T-15.2 (19 steel wires per share IWR stainless steel wire rope with a wire contact steel core and a diameter of 15.2 mm), and the nominal tensile strength of the steel rope is 17000 kg / cm 2 (i.e. 1670 N / mm 2 ), the safety factor is 3, and the allowable stress is 5666.7 kg / cm 2 , the maximum breaking force of the steel rope is about 150.7 t; the calculation results are shown in Table 3 below; Table 3: Forces on the steel rope and anchor at various design flow rates

[0036] The friction force generated by the deadweight of the anchor is used to bear the mooring force of the fish intercepting net; in the field engineering design, the designed high water level is 170 m; the designed low water level is 140 m; the deadweight of the anchor structure is: G =10×8×4.5×24=8640 kN; considering the anchor seat is submerged after the buoyancy density is: G= 10 × 8 × 4.5 × 14 = 5040 kN, the friction coefficient between concrete and foundation silty clay is 0.3-0.45, and the friction coefficient is taken in this project f =0.35; the mooring force of the fishing net in this project is 1652.6 kN. After considering the buoyancy weight, the friction force generated by the deadweight of the anchor structure F = f · G '=0.35×5040=1764 kN>The mooring force of the fishing net is 1652.6 kN, which meets the use requirements, and the design of the fish intercepting technology can be completed.

[0037] In the fish interception process design method provided by the present invention, the design, calculation and verification process of the components required for construction in combination with the actual engineering requirements is as follows: 1) The steel rope is designed as follows: When the water level is 170 m, the steel cable moves downstream in a parabola shape on the water surface, and the water blocking section of the fish interceptor (4250 m 2 ) / cable length (288.8 m) = 14.72 m 2 / m; When the water level drops, the vertical projection of the steel cable gradually approaches a straight line with the anchors on both sides, and the underwater part of the fish intercepting net becomes a net bag shape downstream. The water blocking section of the above-water part is slightly reduced because a small amount of it is laid on the bank slope. For the sake of conservatism, the reduction factor of the water blocking section of the fish intercepting net is ignored at other water levels, and 14.72 m is still used. 2 / m; the drag force on the steel rope facilities caused by the design water flow of 0.85m / s w For (C d =2.0, water blocking height 14.72 m 2 / m, water resistance 30%): w =[1.0 / (2×9.81)]×2.0×(0.3×14.72)×0.85 2 =0.33 (t / m); Half of the distance between the two banks is 288.8 m, which is 144.4 m. The maximum sag length of the steel rope parallel to the water flow is 40 m. The maximum axial tension of the steel rope is P for: P =0.33×144.4×[1+144.5 2 / (4×40 2 )] 1 / 2 =98.87(t); Taking the safety factor as 1.5, the design shaft tension is: P d =98.87×1.5=148.31(t); The stainless steel rope is 19T-15.2, and the nominal tensile strength (fs) of the material is 17000 kg / cm 2 , the safety factor is 3, and the allowable stress and allowable tension are: f=17000 / 3=5666.7(kg / cm 2 ); P a =(5666.7×1.4×19) / 1000=150.7(t); Review results: P d < P a , meeting the requirements.

[0038] 2) The design of PE rope, buoyancy of buoy and anchor block is as follows The PE rope, buoyancy of the buoy and the anchor block are designed with a spacing of 1.7 m as the unit width, and the calculation is carried out at the maximum length of the steel rope parallel to the water flow; Water flow thrust per unit width P for: P =0.33×1.7=0.561(t)=561(kg); Strength conditions such as Figure 2 As shown, Fx= P =561 (kg); Take the buoy as the origin, according to the moment balance: 561×15+Fy×40=561×30, calculate Fy=210.4 (kg); thus: (Ⅰ)PE rope: Rope axis tension P = (561 2 +210.4 2 ) 1 / 2 =599.2 (kg); Designed with nylon rope (16 mm ψ), high tensile strength P u is 4.78 t, the safety factor is 3, and the verification results are as follows: P a=4.78×1000 / 3=1593(kg)> P =599.2 (kg), meets the requirements; (II) Float: Buoyancy = Fy = 210.4 kg. Considering the sudden impact force that exceeds the design, the design buoyancy is 1.1 times the buoyancy, about 231.4 kg. The buoy provided by the manufacturer can only be used if it is greater than this design value; (III) Anchor block The vertical force per unit width is 210.4 kg and the concrete density is 2.4 t / m 3 , the volume of the anchor block is: V = (210.4 / 1000) / (2.4-1.0) = 0.15 (m 3 ).

[0039] 3) The design of the steel rope clamp is as follows: like Figure 3 As shown, the steel parts are made of ASTM A36 with a nominal tensile strength of 2500 kg / cm 2 , and the tensile strength under repeated stress is reduced to 840 kg / cm 2 ; Shear stress is: F v =0.3Fy=0.3×840=252 (kg / cm); Stainless steel parts: width is 4 cm, there are 9 sets of clamps in a unit width of 1.7 m, and the allowable shear force is: F a =(4×2t)×9×252=18144×t>561(kg,t>0.031 cm), 6 mm stainless steel sheet is used in the design; Bolt: Take the center of the tendon as the origin to balance the moment, assuming that the bolt tension is F and the shear force is F v : 561×100=F×9×80, F=77.9 (kg); 210.4=9×F v , F v =23.4 (kg); That is, the bolt tension must be greater than 77.9 kg and the shear force must be greater than 23.4 kg.

[0040] 4) The design of the buoy fixture is as follows: like Figure 4 As shown, the steel parts are made of ASTM A36 with a nominal tensile strength of 2500 kg / cm 2 , and the tensile strength under repeated stress is reduced to 840 kg / cm 2 .

[0041] Shear stress is: F v =0.3Fy=0.3×840=252(kg / cm 2 ) Stainless steel parts: The width is 4 cm, there are 4 sets of clamps in a unit width of 1.7 m, and the allowable shear force is: F a =(4×2t)×4×252=8064t(kg)>561(kg); t>0.07(cm), the design adopts 6mm stainless steel sheet; Bolt: Take the center of the tendon as the origin to balance the moment, assuming that the bolt tension is F and the shear force is F v : 561×338=F×4×286, F=165.8 (kg); 210.4=4×F v , F v =52.6 (kg); The bolt tension must be greater than 165.8 kg and the shear force must be greater than 52.6 kg.

[0042] 5) The design of the steel plate connecting the buoy and the tendon is as follows: The steel parts are made of ASTM A36 with a nominal tensile strength of 2500 kg / cm 2 , and the tensile strength under repeated stress is reduced to 840 kg / cm 2 .

[0043] Shear stress is: F v =0.3Fy=0.3×840=252(kg / cm 2 ); Assuming the steel plate thickness is t, 561=100×t×252, t=0.022 (cm), the design uses 6 mm stainless steel sheet.

[0044] The steps for implementing the fish interception technology on site of this project are as follows: S1. Based on the engineering scheme determined by the above design method, prepare the components of the corresponding inlet channel headworks fish interception system and carry out on-site construction; S2. Due to the complex underwater terrain, we first use small and medium-sized motor boats to drag the toothed iron roller to repeatedly drag and roll the underwater net base to "sweep the bed", loosen the stiff bamboo and wood bushes on the bottom of the channel, press them down to the ground, and make them lose the ability to support the blocking net, so as to ensure that the bottom of the blocking net sinks to the bottom; S3. After fixing the two ends of the fish blocking net to the anchorages on both sides and positioning and shaping them, use a small boat to hang the main weight at the intersection of each longitudinal force line and the main weight line; for example, between the longitudinal force lines, hang small weights every 2 meters or so, and hang medium weights every 5 meters or so; S4. After the main weight is tied, the floating fence is tied to the floating net. The anchor rope is tied at the junction of the floating net and the longitudinal force net (the length of the anchor rope is more than 3 times the water depth at the anchoring place), connected to the iron anchor, and the back-pulling rope is tied to the anchor rope. Each small boat pulls the anchor rope and the back-pulling rope on the longitudinal force net to make the intercepting net form an arch, then the iron anchor is dropped, the fish intercepting net is fixed, and then the float is tied.

[0045] After the construction is completed, in order to extend the service life of the fish interception facilities, good management and maintenance work must be done. Regular inspections should be carried out in the water to check whether there are gaps between the main cable rope, floating fence, and the line with weight rings and the bottom of the reservoir, whether the net is damaged or buried by mud and sand, whether the weight parts have fallen off, whether the weight rings (blocks) are sufficient, etc., and problems should be dealt with in time. During floods, personnel should be organized to check the fish interception and pollution interception nets, reinforce the fish interception nets, and remove floating objects in front of the pollution interception nets. Pay attention to prevent the upper part of the fish interception net from being aged due to long-term exposure to sunlight. When the water level in the reservoir drops, the fish interception net should be lowered accordingly, and the exposed part of the net after the water level drops should be adjusted, and damage should be repaired in time.

[0046] In summary, the fish interception process design method of the present invention has the advantages of comprehensive consideration of environmental factors, strong guidance, and high scientificity. It is suitable for different practical application environments, can better adapt to complex water flow conditions and fish behaviors, and reduce the impact on the ecological environment. Guided by the scheme designed by the method, the corresponding fish interception process construction method of the present invention is used for engineering operations, which has the advantage of simple operation, and can efficiently complete the construction plan provided by the fish interception process design method of the present invention, meeting the requirements of water diversion engineering and ecological friendliness.

[0047] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for designing a fish intercepting process, characterized in that: The steps include: (1) Determine the type and specifications of fish interceptors and construct a fish interceptor system at the headwater of the water diversion project; the fish interceptor facilities of the headwater fish interceptor system include a force-bearing structure, a main body, a floating fence, and an anchor seat; (2) The force-bearing structure of the fish-blocking facility is a steel rope. Force calculations are performed to determine the structure and length of the steel rope; (3) The main body of the fish interception facility is the fish interception net, and the shrinkage coefficient and mesh size of the net must be determined; (4) Determine the method of fixing the floating boom of the fish intercepting facility and conduct stress analysis on the anchor seat; complete the design of the fish intercepting technology.

2. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (1), the fish species intercepted are the dominant species determined based on the annual survey of abundant, average and dry fishery resources; the statistical parameters of the intercepted fish size include body length ( L ),weight( W ); the fish species intercepted are mainly juvenile fish.

3. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (1), a certain safety distance is reserved between the fish intercepting facility and the water inlet of the headworks building, and the safety distance is 1.8-2.0 times the width of the headworks section.

4. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (2), the steel rope is dragged by the channel water flow ( w ) drifts downstream in a parabolic shape, causing the steel rope to produce maximum axial tension ( P ), and evenly dispersedly transmitted to the anchor seats on both sides, the forces on the steel rope and the anchor seats are analyzed and calculated accordingly; The calculation formula of the drag force generated by channel water flow on fish interception facilities is as follows: w =( ρ / 2 g )· C d · A · V 2 ； in, ρ is the bulk density of water, 1.0 t / m 3 ; g is the acceleration due to gravity, 9.81 m / s 2 ; C d is the drag coefficient, which takes a value of 2.0; A is the channel water blocking area, m 2 / m; V is the channel flow velocity, m / s; The calculation formula for the maximum axial tension that the steel rope can withstand is as follows: P = wl ·[1+ l 2 / 4 m 2 ] -2 ； in, l 1 / 2 of the channel width, m; m is the deformation width under the rope dragging state, m; The hanging length of the steel rope is greater than the length of the river bottom below the anchor seat elevation. According to the deformation width of the steel rope in the dragging state ( m ) calculates and adjusts its length.

5. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (3), the mesh size ( a ) is calculated based on the fish's body size coefficient, which includes the fish's body length coefficient ( k 1) Body weight coefficient ( k 2) The calculation formula is as follows: a = k 1. L or k 2. W -b ; in, a is the mesh size, cm; L is the body length of the fish, cm; W is the body length of the fish, g; b is a constant, which is a parameter of the relationship between fish length and weight, and its value range is 2.5-3.5; The fish body coefficient is calculated based on the circumference of the intercepted part of the fish body (C), the ratio of the mesh circumference (4a) to the circumference of the intercepted part of the fish body, and the calculation formulas of the body length coefficient (k1) and the weight coefficient (k2) are as follows: c = 4a / C; k1=(c / 4)·(C / L); k2=(c / 4)·(C / W -b ); Where C is the circumference of the intercepted part of the fish body, cm; Body length coefficient ( k 1) has a value range of 0.12-0.21; the weight coefficient ( k 2) The value range is 4.13-6.

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6. The method for designing a fish interception technique according to claim 1, characterized in that: In step (3), the mesh sizes of different water layers are set according to the water level at the head of the canal and the ecological habits of fish inhabiting the upper, middle and bottom layers; the actual production height and length of the fish intercepting net are increased by 10%-20% compared with the designed size.

7. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (3), the unfolded view of the net is trapezoidal, with the net material being thick at both ends and thin in the middle; the open shape of the net mesh is similar to and slightly smaller than the shape of the cross-section of the fish body; the shrinkage coefficient includes transverse and longitudinal shrinkage coefficients, the transverse shrinkage coefficient is 0.40-0.57, and the longitudinal shrinkage coefficient is 0.82-0.92; the fish intercepting specifications of the net are 10%, 25%, 50%, 75%, and 90% of the fish body length frequency; wherein a frequency of 10% represents that the intercepted juvenile fish are large in size, a frequency of 25% represents that the intercepted juvenile fish are large in size, a frequency of 50% represents that the intercepted juvenile fish are average in size, a frequency of 75% represents that the intercepted juvenile fish are small in size, and a frequency of 90% represents that the intercepted juvenile fish are small in size.

8. The method for designing a fish intercepting process according to claim 1, characterized in that: In the step (4), the floating grid is vertically sunk to the bottom by means of a counterweight and horizontally anchored by means of a cross-traction method.

9. The method for designing a fish intercepting process according to claim 1, characterized in that: In step (4), considering the floating bulk density, the anchor deadweight ( G ') The friction force generated ( F ) is greater than the mooring force of the fish net; the calculation formula for the friction force generated by the deadweight of the anchor is as follows: F = f · G '； in, f is the friction coefficient; G ' is the deadweight of the anchor considering the buoyancy density, kN. According to the actual application of the present invention, the friction coefficient is determined based on the concrete and the foundation silty clay; The friction coefficient ranges from 0.3 to 0.

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10. A method for implementing a fish interception process, comprising the following steps: S1. Based on the engineering scheme determined by the fish interception process design method described in any one of claims 1 to 9, prepare the components of the corresponding water inlet channel headworks fish interception system and carry out on-site construction; S2. Before setting up the fish blocking net, clean the base of the net and ensure that the net is sunk to the bottom; S3, fix the two ends of the fish blocking net on the anchor seats on both sides, separate the upper and lower wires out of the water, and use the weight to temporarily position and shape them; then hang the main weight at the intersection of each longitudinal wire and the main weight; S4. After the main ballast is tied, the floating boom is tied to the buoy network; the anchor rope is tied at the junction of the buoy network and the longitudinal force network, connected to the anchor, and the pull rope is tied to the anchor rope; the anchor rope and the pull rope on the longitudinal force network are pulled to make the intercepting net form an arch, and then the anchor is dropped, the fish intercepting net is fixed, and the float is tied.

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