AU2021101674A4

AU2021101674A4 - Triangular Water Measuring Weir

Info

Publication number: AU2021101674A4
Application number: AU2021101674A
Authority: AU
Inventors: Caixia CHENG; Haojun MENG; Shunli Wang; Wanqi ZENG; Weijun ZHAO
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-05-27
Anticipated expiration: 2029-03-31

Abstract

A triangular water measuring weir, which comprises a water collecting weir groove, a water gauge and a weir plate. The water collecting weir groove is composed of two parallel weir bodies, and the cross section of the water collecting weir groove is a rectangular groove. A water gauge and a weir plate are provided at the inner side of the tail end of the water collecting weir groove, which is characterized in that, a splayed cut-off wall is provided at the head end of the water collecting weir groove, and the splayed cut-off wall encloses a sedimentation tank; the small mouth end of the splayed cut-off wall is butted with the two weir bodies of the water collecting weir groove; both the water collecting weir groove and the splayed cut-off wall are made of C35 concrete, and the foundation is made of C35 fine-grained concrete masonry; a V-shaped weir is provided in the middle of the top end of the weir plate. The triangular water measuring weir of rubble concrete of the invention has simple structure, convenient production, small floor area and filling amount of rubble concrete and low engineering cost; and the use of weir head can accurately measure the flow rate, with high measurement precision and accuracy, convenient and labor-saving operation and strong ability to resist mountain torrent erosion. 1/1 A a b Figure 1 4 5 51 3 Figure 2 A-A 3 7 B H h p

Description

1/1

A a b

Figure 1

4 5 51 3

Figure 2 A-A 3 7 B

H h

p

I

Descriptions

Triangular Water Measuring Weir

Technical Field The invention relates to a triangular water measuring weir, which is used to measure the river runoff flow in a small watershed.

Background Technology With the continuous maturity of the triangular water measuring weir technology, when the scientific research units and colleges and universities related to water conservancy, hydropower and water transport engineering conduct hydraulic model tests, most of the equipment for measuring flow is the thin-walled rectangular and triangular water measuring weirs of the braiding channel weir groove. However, the current design and application of triangular water measuring weirs are still very irregular, and there are many unreasonable phenomena. In particular, there is no public practical measuring device for triangular water measuring weir of rubble concrete. The triangular water measuring weir of rubble concrete of the invention has the advantages of high precision, high stability, high reliability, convenient and labor-saving operation, small floor area and filling amount of rubble concrete, low engineering cost and strong ability to resist mountain torrent erosion. Therefore, the invention analyzes, discusses and standardizes the design requirements and technology of the triangular water measuring weir; determines a more practical, accurate and simple calculation formula for the calculation and publicity of the triangular water measuring weir through experimental comparison, dimension analysis method, weighing verification and other methods; it has practical significance for the construction of hydraulic model.

Summary of the Invention In order to solve the shortcomings of the existing technology, the purpose of the invention is to provide an observed and practical triangular water measuring weir of rubble concrete. The technical solution of the invention is as follows: a triangular water measuring weir, which comprises a water collecting weir groove, a water gauge and a weir plate. The water collecting weir groove is composed of two parallel weir bodies, and the cross section of the water collecting weir groove is a rectangular groove. A water gauge and a weir plate are provided at the inner side of the tail end of the water collecting weir groove, which is characterized in that, a splayed cut-off wall is provided at the head end of the water collecting weir groove, and the splayed cut-off wall encloses a sedimentation tank; the small mouth end of the splayed cut-off wall is butted with the two weir bodies of the water collecting weir groove; both the water collecting weir groove and the splayed cut-off wall are made of C35 concrete, and the foundation is made of C35 fine-grained concrete masonry; a V-shaped weir is provided in the middle of the top end of the weir plate. The water collecting weir groove is 10m long, 1.5m high, and 1.Om wide at the upper mouth; the splayed cut-off wall is 0.5m wide, 8m long, and its bottom width gradually changes from 7m at the large mouth end to 6m at the small mouth end, and its bottom end should extend into the bedrock layer, and the bedrock layer should be free of cracks, flaws, weathering and interlayer, so as to ensure that all water at the outlet of the small watershed enters the water collecting weir groove and flows out from the V-shaped weir of the weir plate; the splayed cut-off wall is built with C35 fine-grained concrete masonry, and 15-25% volume ratio of rubble is mixed in proportion during concrete pouring, and the particle size of the rubble is controlled below 30cm; concrete is placed first and then rubble is placed to ensure that the concrete slurry is fully wrapped, and the rubble should be evenly arranged in the cut-off wall structure space. The water gauge is provided in the water collecting weir groove at the upstream of the weir; the weir plate is provided perpendicular to the end of the water collecting weir groove, the weir plate is made of stainless steel plate, the thickness of the steel plate is 0.7cm, and the surface should be flat and smooth. The V-shaped weir is an isosceles triangle notch with the angular point downward, the vertex angle 0 can be made into 30, 45, 60°, 900 or 1200. The V-shaped weir is 50cm high and the upper mouth is 1.2m wide, and both sides of the weir plate extend into the inner side 10cm of the water collecting weir groove. The edge of the V-shaped weir is cut into a sharp edge to make it into a thin-walled weir; the bottom end of the water collecting weir groove is higher than the downstream riverbed by 40cm, so the energy dissipation effect of the water flow over the weir is better.

The formula for calculating the flow rate Q of the triangular water measuring weir is as

follows: Q=KxH Where, K = C 2g tan( ), c, = (h, ,o), p is the distance from the vertex angle of

the triangular weir to the bottom of the weir, B is the width of the weir, h is the height of the

waterhead, g is the acceleration of gravity, 0 is the degree of the vertex angle of the V-shaped

weir, H is the measured water level (cm), and Q is the river runoff flow (m3 • s).

The advantages of the invention are as follows: The triangular water measuring weir of rubble concrete of the invention has a reasonable design, and the weir body conforms to the water flow requirements of the national standard weir. The use of rubble concrete can greatly reduce the cost of building a water measuring weir, reduce the amount of concrete pouring, and the project cost is lower; and the use of weir head can accurately measure the flow rate, with high measurement precision and accuracy, convenient and labor-saving operation and strong ability to resist mountain torrent erosion.

Brief Description of Drawings Figure 1 is a top view schematic diagram of the weir body structure of the invention; Figure 2 is a left view of convex1 (rotated 90 counterclockwise) Figure 3 is a A-A sectional view of Figure 1. Description of Drawing Marks: 1. Splayed cut-off wall, 2. Sedimentation tank, 3. Water collecting weir groove, 4. Water gauge, 5. Weir plate, 6. Water level line, 7. Weir body of water collecting weir groove, 51. V-shaped weir on weir plate.

Detailed Description of the Presently Preferred Embodiments As shown in Figure 1-Figure 3, a triangular water measuring weir of the invention, which comprises a water collecting weir groove 3, a water gauge 4 and a triangular weir plate 5. The water collecting weir groove 3 is composed of two parallel weir bodies 7, and the cross section of the water collecting weir groove 3 is a rectangular groove. A water gauge 4 and a weir plate 5 are provided at the inner side of the tail end of the water collecting weir groove 3, and a V-shaped weir 51 is provided in the middle of the top end of the weir plate 5. In order to prevent erosion and damage on both banks of the river channel in front of the water measuring weir and affect the normal operation of the water measuring weir, the splayed cut-off wall 1 in front of the weir is used to protect both banks of the river channel in front of the weir. That is, a splayed cut-off wall 1 is provided at the head end of the water collecting weir groove 3, and the splayed cut-off wall 1 encloses a sedimentation tank 2; the small mouth end of the splayed cut-off wall 1 is butted with the two weir bodies of the water collecting weir groove 3; both the water collecting weir groove 3 and the splayed cut-off wall 1 are made of C35 concrete, and the foundation is made of C35 fine-grained concrete masonry. The water collecting weir groove 3 is 10m long, 1.5m high, and 1.Om wide at the upper mouth; the splayed cut-off wall 1 is 0.5m wide, 8m long, and its bottom width gradually changes from 7m at the large mouth end to 6m at the small mouth end, and its bottom end should extend into the bedrock layer, and the bedrock layer should be free of cracks, flaws, weathering and interlayer, so as to ensure that all water at the outlet of the small watershed enters the water collecting weir groove 3 and flows out from the V-shaped weir 51 of the weir plate 5; the splayed cut-off wall 1 is built with C35 fine-grained concrete masonry, and 15-25% volume ratio of rubble is mixed in proportion during concrete pouring, and the particle size of the rubble is controlled below 30cm; concrete is placed first and then rubble is placed to ensure that the concrete slurry is fully wrapped, and the rubble should be evenly arranged in the cut-off wall structure space. The water gauge 4 is provided in the water collecting weir groove 3 at the upstream of the weir; the weir plate 5 is provided perpendicular to the end of the water collecting weir groove 3, the weir plate 5 is made of stainless steel plate, the thickness of the steel plate is 0.7cm, and the surface should be flat and smooth. The V-shaped weir 51 is an isosceles triangle notch with the angular point downward, the vertex angle 0 can be made into 30, 450, 60°, 90° or 120, generally 90. The V-shaped weir 51 is 50cm high and the upper mouth is 1.2m wide, and both sides of the weir plate 5 extend into the inner side 10cm of the water collecting weir groove 3. The edge of the V-shaped weir 51 is cut into a sharp edge to make it into a thin-walled weir; the bottom end of the water collecting weir groove 3 is higher than the downstream riverbed by cm, so the energy dissipation effect of the water flow over the weir is better. Its characteristic is that it still has a large waterhead at a small flow rate, and has a high measurement precision, which is suitable for measuring small flow rates. A water gauge can be used to manually observe the water level or a self-recording water gauge is installed to automatically monitored the water level. In order to ensure that the flow rate of the water across the weir is even and stable, the observation station is selected in a river channel with straight channel, stable bank slope and gentle riverbed. The splayed cut-off wall 1 of the sedimentation tank 2 is 8m long, and its bottom width gradually changes from 7m at the large mouth end to 6m at the small mouth end. The water flow regime in the sedimentation tank 2 is stable, and the water can be smoothly introduced into the water collecting weir groove 3, so as to accurately measure the water level. The water gauge 4 is provided in the water collecting weir groove 3 at the upstream of the weir plate 5. As shown in Figure 3, for triangular water measuring weir, when the height of the upstream waterhead changes, the width of the liquid flow of the weir also changes. Therefore, the formula for calculating the flow rate of the triangular weir should be related to the vertex angle 0 of the V-shaped weir 51.

follows: Q=KxH Where, K = C 2g tan , C, = (, ,o), p is the distance from the vertex angle of 152PB

Q =8/15*0.6* POWER(2*9.81,0.5)* TAN(RADIANS(30))* POWER(H,2.5)/100000

When the vertex angle 0 of the triangular water measuring weir is 60, the formula for calculating the flow rate of the above water measuring weir is as follows:

C, = 0.6, K = 0.081835, Q = 0.081835 x H +100 000. The computer input formula is

Q =8/15*0.6* POWER(2*9.81,0.5)* TAN(RADIANS(30))* POWER(H,2.5)/100000

The water measuring weir work is selected at the downstream of the river channel near the river junction. According to local meteorological, hydrological, vegetation and other data, the hydrological analogy method is used to calculate the river runoff results. The design flood peaks are based on the similarity of the design flood peaks, underlying surface vegetation, precipitation and other factors analyzed by the research on the built projects of the river system, and the relationship diagram between the peak discharge of the point confluence and the drainage area. In the area of the river channel where the water measuring weir can not control, the groundwater runoff calculation method is adopted to calculate the underground runoff at the section. The water measuring weir should be located on the bedrock layer, with good foundation bearing performance, no instability, sedimentation and deformation of foundation, and no frost heave of foundation. The buried depth of the foundation should be determined after the calculation of the maximum erosion depth of the riverbed, and should be greater than the maximum depth of the local frozen soil. The height of the water measuring weir is designed according to the water level elevation of the once flood in 10~30 years. The design plan is based on the Water Conservancy and Hydropower Engineering Classification and Flood Standards and the Irrigation and Drainage Engineering Design Specifications. The main works include the weir body of water measuring weir and the weir plate of water measuring weir, etc. The construction site of the water measuring weir should be relatively concentrated, the terraces on both banks should be relatively spacious, and the construction should be arranged according to the dry season of the river channel. During the construction, the normal runoff of the river channel should be taken into consideration, and the newly opened diversion canal of the river channel should be used for diversion with larger diameter pipeline. When the weir body is excavated, the amount of infiltration is large, so drainage measures should be taken, and centrifugal pumps should be used for drainage. According to the selected location of the work, construction conditions, project scale and construction period, the main work must be completed before the flood season. Before the construction period, the erection of transmission lines should be prepared, the temporary construction roads in the river channel should be repaired, and the temporary houses should be constructed.

Claims

Claims 1. A triangular water measuring weir, which comprises a water collecting weir groove 3, a water gauge 4 and a weir plate 5. The water collecting weir groove 3 is composed of two parallel weir bodies 7, and the cross section of the water collecting weir groove 3 is a rectangular groove. A water gauge 4 and a weir plate 5 are provided at the inner side of the tail end of the water collecting weir groove 3, which is characterized in that, a splayed cut-off wall 1 is provided at the head end of the water collecting weir groove 3, and the splayed cut-off wall 1 encloses a sedimentation tank 2; the small mouth end of the splayed cut-off wall 1 is butted with the two weir bodies of the water collecting weir groove 3; both the water collecting weir groove 3 and the splayed cut-off wall 1 are made of C35 concrete, and the foundation is made of C35 fine-grained concrete masonry; a V-shaped weir 51 is provided in the middle of the top end of the weir plate 5.
2. The triangular water measuring weir as described in Claim 1, which is characterized in that, the water collecting weir groove 3 is 10m long, 1.5m high, and 1.Om wide at the upper mouth; the splayed cut-off wall 1 is 0.5m wide, 8 meters long, and its bottom width gradually changes from 7m at the large mouth end to 6m at the small mouth end, and its bottom end should extend into the bedrock layer, and the bedrock layer should be free of cracks, flaws, weathering and interlayer, so as to ensure that all water at the outlet of the small watershed enters the water collecting weir groove 3 and flows out from the V-shaped weir 51 of the weir plate 5; the splayed cut-off wall 1 is built with C35 fine-grained concrete masonry, and 15-25% volume ratio of rubble is mixed in proportion during concrete pouring, and the particle size of the rubble is controlled below 30cm; concrete is placed first and then rubble is placed to ensure that the concrete slurry is fully wrapped, and the rubble should be evenly arranged in the cut-off wall structure space.
3. The triangular water measuring weir as described in Claim 1, which is characterized in that, the water gauge 4 is provided in the water collecting weir groove 3 at the upstream of the weir; the weir plate 5 is provided perpendicular to the end of the water collecting weir groove 3, the weir plate 5 is made of stainless steel plate, the thickness of the steel plate is 0.7cm, and the surface should be flat and smooth. The V-shaped weir 51 is an isosceles triangle notch with the angular point downward, the vertex angle 0 can be made into 30°, 45°, 60°, 90° or 120°. The V-shaped weir is 50cm high and the upper mouth is 1.2m wide, and both sides of the weir plate 5 extend into the inner side 10cm of the water collecting weir groove 3. The edge of the V-shaped weir is cut into a sharp edge to make it into a thin-walled weir; the bottom end of the water collecting weir groove 3 is higher than the downstream riverbed by 40cm, so the energy dissipation effect of the water flow over the weir is better.
4. The triangular water measuring weir as described in Claim 1, which is characterized in

that, the formula for calculating the flow rate Q of the triangular water measuring weir is as follows: Q=KxH2 Where, K = C 8 2 gtan() , C, =f( ,,), p is the distance from the vertex angle of the triangular weir to the bottom of the weir, B is the width of the weir, h is the height of the waterhead, g is the acceleration of gravity, 0 is the degree of the vertex angle of the V-shaped weir, H is the measured water level (cm), and Q is the river runoff flow (m3 s-1).