Riverbed protection device and protection method with wading bridge

Abstract

The present invention relates to the technical field of scour protection for foundations of wading bridges, and specifically to a riverbed protection device and a protection method for wading bridges. It includes an air aeration system for introducing gas into river water to reduce the scouring of the riverbed by water flow at the bridge piers, a parameter detection unit for detecting water flow parameters, and a control system for sending instructions to the air aeration system based on data obtained by the parameter detection unit; the output end of the parameter detection unit is connected to the input end of the control system, and the output end of the control system is connected to the input end of the air aeration system. Introducing a certain pressure of gas into the river water from the riverbed surface can change the water flow structure around the bridge piers, hinder the water flow in front of the bridge piers from diving or the turbulent vortex around the bridge piers from scouring the riverbed and taking away the silt around the bridge piers, thereby reducing the impact of the water flow on the bridge foundation and ensuring the stability of the bridge foundation.

Description

Technical Field

[0001] The invention relates to the technical field of scour protection for foundations of wading bridges, and in particular to a riverbed protection device and a protection method for a wading bridge. Background Art

[0002] The bridge piers set in the river channel reduce the water flow area of ​​the original river channel at the bridge location, and the water flow in the river channel section at the bridge location is accelerated. In addition, the underwater current in front of the pier, the horseshoe vortex around the pier, and the vertical tubular tail vortex form a complex turbulent vortex system around the pier. The violently disturbed vortex carries away the riverbed sediment around the pier to form a local scouring area. The local scouring of the pier foundation will reduce the burial depth of the bridge foundation, causing damage to the bridge foundation and a decrease in the bridge bearing capacity. Especially during floods, the scouring is severe, which may cause the pier to become unstable and the bridge to overturn. Although people have conducted in-depth research on the local flow field structure of the pier, the characteristics of sediment erosion and transportation, and the evolution characteristics of local scouring pits, it is still difficult to fully grasp the evolution mechanism of local scouring due to the complexity of the turbulent vortex system. It is a common method to use certain engineering measures to protect the bridge foundation from local scouring. Since local scouring is affected by factors such as water flow state, pier shape, bed sand composition, and riverbed morphology, the existing local scouring protection effects of bridge foundations are insufficient.

[0003] The violently disturbed vortex takes away the riverbed sediment around the bridge piers to form a shallow bridge foundation. The shallow bridge foundation means that the sediment around the bridge piers is reduced due to the sediment around the bridge piers being taken away. Shallow-foundation bridges not only threaten driving safety during the flood season, but also seriously cause the bridge piers to become unstable and the bridge to overturn.

[0004] Therefore, there is an urgent need to solve the problem of river water scouring away the silt around the bridge piers to reduce the impact of scouring on the bridge piers. Summary of the invention

[0005] In order to solve the above technical problems, one of the purposes of the present invention is to provide a riverbed protection device with a wading bridge, which locally changes the water flow structure by blowing gas into the river water, reduces the scouring effect of the water flow, reduces the impact of the water flow on the bridge foundation, and ensures the stability of the bridge foundation.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A riverbed protection device with a wading bridge includes an aeration system for introducing gas into river water to reduce the scouring of the riverbed by water flow at bridge piers, a parameter detection unit for detecting water flow parameters, and a control system for sending instructions to the aeration system based on data obtained by the parameter detection unit; the output end of the parameter detection unit is connected to the input end of the control system, and the output end of the control system is connected to the input end of the aeration system.

[0008] Furthermore, the aeration system includes a blower and a scour protection pipe network, and the blower is connected to the scour protection pipe network; the output end of the control system is connected to the driving end of the blower.

[0009] Furthermore, the scour protection pipe network is arranged on the upstream water side of the bridge pier and / or the scour protection pipe network is arranged around the bridge pier.

[0010] Furthermore, the scour protection pipe network includes an aeration pipeline connected to the blower, an aeration head arranged on the aeration pipeline and connected to the aeration pipeline, and each aeration pipeline is connected to each other.

[0011] Further preferably, the top and / or side and / or bottom of the aeration head are provided with air outlet holes.

[0012] Further, the parameter detection unit includes a water pressure sensor, and the output end of the water pressure sensor is connected to the input end of the control system; or, the parameter detection unit includes a flow rate sensor, and the output end of the flow rate sensor is connected to the input end of the control system; or, the parameter detection unit includes a water pressure sensor and a flow rate sensor, and the output end of the water pressure sensor is connected to the first input end of the control system, and the output end of the flow rate sensor is connected to the second input end of the control system.

[0013] Further preferably, an outer cover is provided on the outside of the water pressure sensor, and the outer cover is hollow.

[0014] The second object of the present invention is to provide a riverbed protection method with a wading bridge, comprising the following steps:

[0015] S1, obtain the flow parameters of the river water;

[0016] S2: If the water flow parameter is greater than the first set value, the external gas is transported into the river water until the water flow parameter is less than the second set value, and then the gas transport is stopped.

[0017] Furthermore, the specific steps of obtaining the water flow parameters in step S1 are as follows:

[0018] Acquiring water flow parameters through a parameter detection unit, wherein the water flow parameters include water pressure and / or flow velocity of river water;

[0019] The specific steps of step S2 are as follows:

[0020] If the water flow parameter is greater than the first set value, the blower will transport the external gas into the river water through the aeration pipe and the aeration head in sequence until the water pressure is less than the second set value, and the blower stops transporting the gas; the aeration pipe is fixed in the riverbed, and the aeration pipe is located on the upstream water side of the pier and / or around the pier.

[0021] Further preferably, the top of the aeration head is located at the interface between the river water and the riverbed and / or the aeration head is located in the river water, and the aeration head jets upward and / or the aeration head jets downward and / or the aeration head jets horizontally.

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

[0023] (1) When river water flows from upstream to the bridge piers, under the combined influence of its own downward gravity and the horizontal force of the bridge piers, the river water forms vortices around the bridge piers. The vortices drive the sediment on the riverbed to move, reducing the sediment at the location of the bridge piers to form vortex pits, which will affect the stability of the bridge piers.

[0024] Introducing gas into the river water can change the water flow structure around the bridge piers, hinder the water flow in front of the piers from diving or the turbulent vortex around the piers from scouring the riverbed, thereby reducing the impact of the water flow on the bridge foundation and ensuring the stability of the bridge foundation.

[0025] (2) In dynamic river water, the deeper the water level and the greater the water flow rate, the greater the water pressure. Under the premise that the water level remains unchanged, the water flow rate can be known by detecting the water pressure. According to the size of the water pressure, the working state of the blower can be automatically controlled, which can realize automatic control and real-time monitoring.

[0026] (3) The water pressure sensor is installed at the junction of the riverbed and the river water. This is because the river water there is the main factor affecting the formation of the vortex. Detecting the water pressure there can improve accuracy.

[0027] (4) The water pressure sensor is installed at the junction of the riverbed and the river water on the backwater side of the bridge pier. The water pressure detected at this location can represent the characteristic value of the scouring water flow and can also avoid direct erosion by the river water flow.

[0028] (5) The aeration head is fixed in the river water, which can directly diffuse the external gas into the river water, reducing the time of gas diffusion, so as to timely reduce the vortex formed by the water flow and achieve the purpose of protecting the bridge pier. The aeration head is fixed in the riverbed, which can prevent objects carried by the river water from hitting the aeration head and causing damage to it.

[0029] (6) The present invention collects the pressure at the water pressure sensor through the water pressure sensor, and the judgment system sends instructions to the control system according to the water pressure signal. The control system controls the opening and closing and output power of the aeration blower according to the instructions. The airflow or upward bubbles generated by the aeration head of the pneumatic system can change the water flow structure in the anti-scouring area of ​​the riverbed surface, hinder the water flow in front of the pier from diving or the turbulent vortex around the pier from scouring the riverbed, reduce the impact of the water flow on the bridge foundation, and achieve the purpose of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 and Figure 2It is the overall structure diagram of the present invention;

[0031] Figure 3 It is a structural diagram of the scour protection pipe network of the present invention.

[0032] The meanings of the symbols in the figure are as follows:

[0033] 10-bridge pier 11-tie beam 12-anchor rod 20-blower 21-control system 22-housing

[0034] 23- air duct 24- flow rate sensor 25- outer cover 26- water pressure sensor

[0035] 27-air aeration pipeline 28-aeration head DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solution of the present invention in combination with the embodiments and the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] A riverbed protection device with a wading bridge includes an aeration system for introducing gas into river water to reduce scouring of the riverbed by water flow at a bridge pier 10, and a parameter detection unit for detecting water flow parameters. In this embodiment, the aeration system introduces gas into the river water from bottom to top, and a control system 21 is used to send instructions to the aeration system based on data obtained by the parameter detection unit; the output end of the parameter detection unit is connected to the input end of the control system 21, and the output end of the control system 21 is connected to the input end of the aeration system.

[0039] like Figure 1 As shown, the aeration system includes a blower 20 fixedly mounted on the tie beam 11 of the bridge, an air guide pipe 23 at the air outlet of the blower 20, an aeration pipe 27 connected to the air guide pipe 23 and fixed in the riverbed, and an aeration head 28 fixedly mounted on the aeration pipe 27. The aeration pipe 27 can be fixed only on the water side of the pier 10, i.e., the water side facing the water. Figure 2 As shown, aeration pipes 27 may also be fixed around the pier 10. The aeration head 28 may be located in the riverbed or may extend into the river water.

[0040] like Figure 1 As shown, the air guide pipe 23 includes three sections of pipes, the two end sections are connected to the blower 20 and the aeration pipe 27 respectively, and the middle section is fixed in the pier 10, which can increase the firmness of the air guide pipe 23.

[0041] The control system 21 and the blower 20 are provided with a housing 22 outside to prevent external factors from affecting their normal operation.

[0042] The number of aeration pipes 27 is several, such as Figure 3 As shown, each aeration pipe 27 constitutes a rectangular pipe network or an annular pipe network, and the aeration heads 28 are evenly distributed in the rectangular pipe network. The disc-type aeration head 28 has a small aeration bubble diameter, a small gas-liquid interface diameter, a large gas-liquid interface area, uniform bubble diffusion, no hole blockage, and strong corrosion resistance. Anchor rods 12 are connected to the bottom of the aeration pipe 27, and the anchor rods 12 are fixed in the sand and gravel to increase the firmness of the aeration pipe 27 and prevent it from being washed away by water. The vertical width of the rectangular pipe network is not less than the width of the pier 10 / or the annular width is not less than the maximum outer edge size of the pier 10.

[0043] The parameter detection unit can be a water pressure sensor 26, or a flow rate sensor 24, or the water pressure sensor 26 and the flow rate sensor 24 are used together. In this embodiment, the parameter detection unit is a water pressure sensor 26, model WMY-BQ. The water pressure sensor 26 is fixed on the backwater side of the bridge pier 10, and an outer cover 25 is provided on the outside of the water pressure sensor 26. The outer cover 25 is hollow, which can prevent the water flow on the water side from impacting the water pressure sensor 26. The use of the water pressure sensor 26 can avoid the problem of being difficult to protect due to the large water flow, and can also avoid the problem of the detection instrument being easily washed away by mud and sand.

[0044] The control system 21 includes a controller and a judger. The judger is used to judge whether the water pressure reaches a set value, and the controller is used to send instructions to the blower 20.

[0045] Example 2

[0046] Based on Example 1, a protection method using a riverbed protection device includes the following steps:

[0047] S1, fix the water pressure sensor 26 on the upstream water side of the bridge pier 10, and the bottom of the water pressure sensor 26 is located at the junction of the river water and the riverbed, so as to obtain the water pressure at the interface between the river water and the riverbed.

[0048] S2, if the water pressure is greater than the first set value, the external gas is transported to the river water by forming an airflow with a certain pressure through the blower 20. The airflow pressure formed by the blower 20 needs to change with the water flow parameters of the river water until the water flow parameters are less than the second set value, then the gas transportation is stopped. Then the external gas is transported to the junction of the river water and the riverbed, and the gas moves upward and diffuses into the river water to reduce the scouring of the riverbed by the river water; or, the external gas is transported to the river water; until the water pressure is less than the second set value, then the gas transportation is stopped. The specific steps are as follows:

[0049] The water pressure obtained by the water pressure sensor 26 is transmitted to the control system 21 through a wire. If the water pressure is greater than the first set value, the blower 20 will transport the outside air through the air guide pipe 23, the air-blowing aeration pipe 27, and the aeration head 28 to the river water in sequence until the water pressure is less than the second set value, then the blower 20 stops transporting the air.

[0050] Working principle: First, install the device according to the installation method as Figure 1 shown. Then, collect the pressure at point A through the water pressure sensor 26. The judgment system sends instructions to the automatic control system 21 according to the water pressure signal. The control system 21 controls the opening and closing and output power of the aeration blower 20 according to the instructions. The aeration blower 20 works at the corresponding output power, so that the aeration head 28 generates a certain amount of bubbles or airflows. The upward movement of the bubbles or airflows can change the water flow structure in the anti-scouring area of the riverbed surface, hinder the downstream flow of the water in front of the pier or the scouring of the riverbed by the turbulent vortices around the pier 10, so as to reduce the impact of the water flow on the bridge foundation and ensure the stability of the bridge foundation.

[0051] Take a part of the water body above the aeration head device as the research object. Let the force exerted on this water body by the pressure (σb + σair) at point B be F1, the force exerted on this water body by the water pressure above this water body be F2, the buoyancy force on this water body be F3, the downward acceleration of this water body be set as a, the mass of this water body be m, and the gravitational acceleration be g.

[0052] According to Newton's second law: F2 + mg - F1 - F3 = ma. To hinder the downward flow of the downward flow of water and indirectly hinder the formation of the horseshoe vortex and slow down the scouring of the water flow on the bridge foundation, then a < 0, and the greater the value of a, the better the hindering effect and the better the anti-scouring effect. Therefore, different values of a can be obtained by controlling the magnitude of F1. And under the action of different output powers p of the blower 20, the amount of bubbles generated is different, which will make the pressure (σb + σair) at point B different, so as to obtain different F1. From the perspective of energy, it is required that the work done by the blower 20 at a certain power and the potential energy of the position of the downward flow sum up to be greater than the kinetic energy of the downward flow.

[0053] If the pressure at point A is σa, the relationship between σb and σa can be determined by the installation position relationship between the aeration head device and the water pressure sensor 26. It can be set that σb = σa + σ1, where σ1 is a certain value. Then the pressure at point B can be expressed as (σa + σair + σ1). Therefore, the pressure σa at point A can be collected through the water pressure sensor 26. The judgment system sends instructions to the control system 21 according to the water pressure signal. The control system 21 controls the output power of the aeration blower 20 to be p according to the instructions, so that the aeration head device generates a certain amount of bubbles, and the pressure is the corresponding σair. Then the pressure at point B is (σa + σair + σ1), and finally a < 0 is achieved.

[0054] When σa reaches a certain constant value σ0, the control system 21 automatically starts the blower 20 to make it have a certain power P; if σa<σ0, the control system 21 will automatically shut down the blower 20.

[0055] The pressure at point A is σa, and at this time the control system 21 controls the blower 20 to output power P:

[0056] If σa>σ0, when the water flow increases or decreases, the pressure at A increases or decreases by △σ, and the pressure becomes σa±△σ. The water pressure sensor 26 transmits the corresponding signal to the control system 21, and the control system 21 automatically adjusts the output power P of the blower 20 to the corresponding P±△P, and finally makes a<0. That is, for different pressures σa at A, the control system 21 can adjust the blower 20 to have the corresponding output power P, so that a<0 in the end.

[0057] If σa=σ0, when the water flow increases, the pressure at A increases by △σ, and the pressure becomes σ0+△σ, then the control system 21 automatically adjusts the output power P of the blower 20 to the corresponding P0+△P, and finally makes a<0; when the water flow decreases, the pressure at A decreases by △σ, and the pressure becomes σ0-△σ, then the control system 21 automatically shuts down the blower 20.

Claims

1. A riverbed protection device with a wading bridge, characterized in that: It comprises an air aeration system for introducing gas into river water to reduce the scouring of the riverbed by water flow at the bridge pier (10) and a parameter detection unit for detecting water flow parameters, and also comprises a control system (21) for sending instructions to the air aeration system based on data obtained by the parameter detection unit; the output end of the parameter detection unit is connected to the input end of the control system (21), and the output end of the control system (21) is connected to the input end of the air aeration system; The aeration system comprises a blower (20) and a scour protection pipe network, wherein the blower (20) is in communication with the scour protection pipe network; an output end of the control system (21) is connected to a driving end of the blower (20); The scour protection pipe network is arranged on the upstream water side of the bridge pier (10) and / or the scour protection pipe network is arranged around the bridge pier (10); The scour protection pipe network comprises an aeration pipe (27) connected to the blower (20) and an aeration head (28) arranged on the aeration pipe (27) and connected to the aeration pipe (27), and each aeration pipe (27) is connected to each other; The aeration head (28) is located in the river bed; An air outlet is arranged at the upper portion of the aeration head (28).

2. The riverbed protection device according to claim 1, characterized in that: The side and / or bottom of the aeration head (28) is provided with air outlet holes.

3. The riverbed protection device according to claim 2, characterized in that: The parameter detection unit comprises a water pressure sensor (26), and an output end of the water pressure sensor (26) is connected to an input end of a control system (21); or, the parameter detection unit comprises a flow rate sensor (24), and an output end of the flow rate sensor (24) is connected to an input end of a control system (21); or, the parameter detection unit comprises a water pressure sensor (26) and a flow rate sensor (24), and an output end of the water pressure sensor (26) is connected to a first input end of the control system (21), and an output end of the flow rate sensor (24) is connected to a second input end of the control system (21).

4. The riverbed protection device according to claim 3, characterized in that: An outer cover (25) is arranged outside the water pressure sensor (26), and the outer cover (25) is hollow.

5. A protection method for a riverbed protection device with a wading bridge using any one of claims 1 to 4, characterized in that: The steps include: S1, obtain the flow parameters of the river water; S2: If the water flow parameter is greater than the first set value, the external gas is transported into the river water until the water flow parameter is less than the second set value, and then the gas transport is stopped.

6. The protection method according to claim 5, characterized in that: The specific steps of obtaining water flow parameters in step S1 are as follows: Acquiring water flow parameters through a parameter detection unit, wherein the water flow parameters include water pressure and / or flow velocity of river water; The specific steps of step S2 are as follows: If the water flow parameter is greater than a first set value, the blower (20) conveys external gas into the river water through the aeration pipe (27) and the aeration head (28) in sequence until the water pressure is less than a second set value, and then the blower (20) stops conveying the gas; the aeration pipe (27) is fixed in the riverbed, and the aeration pipe (27) is located on the upstream water side of the bridge pier (10) and / or around the bridge pier (10).

7. The protection method according to claim 6, characterized in that: The top of the aeration head (28) is located at the interface between the river water and the riverbed and / or the aeration head (28) is located in the river water, and the aeration head (28) sprays upwards and / or the aeration head (28) sprays downwards and / or the aeration head (28) sprays horizontally.

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