A method for preventing salt and a salt collecting pit structure suitable for low salinity salt water environment

Abstract

The application discloses a salt prevention method and a salt collection pit structure suitable for a low-salinity salt water environment. The salt prevention method adopts a mode of locally deepening the salt collection pit at multiple positions to form a segmented salt collection pit structure, so as to increase the water head loss of salt water upwelling, and the segmented salt collection pit structure is repeatedly used to increase and decrease the water depth, so as to continuously change the pressure energy of the salt water and fresh water interface, dissipate the kinetic energy of the salt water, and slow down the speed of the salt water upwelling. The application can slow down the speed and salt content of the salt water invading the upstream, save the engineering cost, and avoid the formation of adverse water flow to cause adverse effects on the navigation safety of ships.

Description

Technical Field

[0001] This invention relates to the field of lock engineering technology, specifically to a method for preventing saltwater infiltration and a saltwater collection pit structure suitable for low-salinity saline water environments. Background Technology

[0002] The construction of high-grade waterways in tidal zones has resulted in significant changes to the river cross-section before and after the project, increasing the tidal volume in the tidal zone. After the project is completed, the frequent operation of the locks has exacerbated the upstream intrusion of saltwater. To address the issue of seawater intrusion at the estuary locks, the current saltwater prevention measures for lock projects mainly include the air curtain method, saltwater collection pit method, replacement method, and liftable saltwater tank method.

[0003] As a commonly used method for preventing saltwater intrusion, the design of saltwater collection pits in current offshore lock projects is mainly aimed at high-salinity offshore saltwater. The movement and erosion of offshore saltwater on structures differ greatly from that of low-salinity / ultra-low-salinity waters in tidal zones. In addition, the existing saltwater collection pits used in lock projects are enormous in size, greatly increasing the construction cost. For example, the area of ​​the saltwater collection pit used in the Tennessee Locks in the Netherlands is 6.7 times the area of ​​the lock itself. Existing lock saltwater collection pits mainly rely on increasing the area and depth of the pit to accumulate saltwater using the density current movement characteristics of the saltwater. However, during operation, salinity accumulation zones are easily formed, and the saltwater effect is significantly weakened after a stable stratification is formed within the collection pit.

[0004] As attached Figure 1 and attached Figure 2 The diagram shows the structure of an existing saline collection pit. The pit is set along the length of the upstream navigation channel, and its length is basically adapted to the length of the channel. The pit is huge in volume and has a flat bottom. In operation, the density difference between fresh and salt water causes the salt water to sink into the pit. However, in the existing technology, after the salt water sinks, it still intrudes upstream at a relatively fast speed at the bottom of the pit. After reaching the end of the pit, the salt water continues to accumulate. In the short term, this can reduce the amount of salt entering the upstream navigation channel to a certain extent, but the salt water will continue to overflow upstream after accumulating at the end. Therefore, after continued operation, the salt water will continue to enter the upstream water. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the existing technology, the technical problem to be solved by the present invention is: how to provide a saltwater prevention method and saltwater collection pit structure that can slow down the speed and salt content of saltwater intrusion upstream, save engineering costs, and avoid the formation of adverse water flow that would have an adverse impact on the navigation safety of ships, and is suitable for low salinity saltwater environments.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for preventing salinity in low-salinity saline water environments is proposed. This method involves creating a segmented salinity collection pit structure by deepening the pits in multiple locations. This increases the head loss of the saline water flowing upstream. Furthermore, the segmented salinity collection pit structure is used to continuously change the pressure energy at the interface between saline and fresh water by repeatedly increasing and decreasing the water depth. This dissipates the kinetic energy of the saline water and slows down its upstream flow.

[0007] A saline water collection pit structure suitable for low-salinity saline water environments is provided. The saline water collection pit structure is distributed along the length direction of the upstream navigation channel, and the overall length of the saline water collection pit structure is less than the length of the upstream navigation channel. Multiple local deepening structures are provided on the saline water collection pit structure along the length direction of the upstream navigation channel so that the saline water collection pit structure as a whole forms a segmented saline water collection pit structure.

[0008] Preferably, the length of the salt collection pit structure is 65%-75% of the length of the upper navigation channel.

[0009] Preferably, the interval length between two adjacent locally deepened structures on the salt collection pit structure is 0.15-0.25 times the length of the upper navigation channel.

[0010] Preferably, the interval length between two adjacent locally deepened structures on the salt collection pit structure is 0.2 times the length of the upper navigation channel.

[0011] Preferably, the height between the bottom of the partially deepened structure and the bottom of the upper approach channel is H, and the height between the bottom of the remaining locations of the salt collection pit structure and the bottom of the upper approach channel is 0.6H.

[0012] Preferably, the length of the locally deepened structure is 0.1 times the length of the upper navigation channel, and the width of the locally deepened structure is adapted to the width of the upper navigation channel.

[0013] Preferably, the salt collection pit structure is provided with a first partial deepening structure, a second partial deepening structure, a third partial deepening structure and a fourth partial deepening structure. The first partial deepening structure is located in the middle and upper reaches of the upper channel, the second partial deepening structure is located in the middle and lower reaches of the upper channel, and the third and fourth partial deepening structures are located at the downstream end of the upper channel (inlet area of ​​the water conveyance system).

[0014] Preferably, the first and second partial deepening structures are distributed along the length of the upper approach channel in a fixed section of the upper approach channel, and the third and fourth partial deepening structures are distributed along the width of the upper approach channel in a transition section of the upper approach channel.

[0015] Preferably, the volumes of the first and second partially deepened structures are both V, and the volumes of the third and fourth partially deepened structures are both V / 3.

[0016] Compared with the prior art, the present invention has the following advantages: 1. Based on the traditional layout of saline collection pits, this invention adopts a segmented saline collection pit structure by using multiple locally deepened structures. This layout not only increases the head loss of saline water flowing upstream, but also continuously changes the pressure energy at the interface between fresh and salt water by repeatedly and suddenly increasing and decreasing the water depth, further dissipating the kinetic energy of the saline water and significantly slowing down the speed of saline water flowing upstream. Combined with the saline drainage facilities arranged at the bottom of the locally deepened pits, it effectively reduces the amount of saline water accumulated due to long-term operation.

[0017] 2. The segmented saline pit structure adopted in this invention utilizes the stratification phenomenon formed by the density difference between fresh and salt water. By segmenting and deepening locally, it significantly reduces the rate of saline water intrusion while greatly reducing the area and volume of the saline pit. In comparison, the area of ​​the saline pit in this invention is only about 70% of that of the upstream navigation channel, which is much smaller than the area of ​​the traditional saline pit. The excavation volume is also much smaller than that of a saline pit of the same area and overall deepened to the same depth.

[0018] 3. This invention can slow down the rate and salt content of saltwater intrusion upstream, reduce the volume of saltwater collection pits, and save engineering costs, so as to avoid the adverse effects of bad water flow on the navigation safety of ships. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the existing salt pit structure; Figure 2 This is a longitudinal sectional view of the existing salt pit structure; Figure 3 A schematic diagram illustrating the intrusion process of low-salinity saline water in the lock when a saline collection pit is not used and when a saline collection pit using existing technology is used; Figure 4 This is a schematic diagram of the salinity collection pit structure applicable to low-salinity saline water environments according to the present invention; Figure 5 This is a longitudinal sectional view of the salinity collection pit structure applicable to low-salinity saline water environments according to the present invention; Figure 6 This is a plan view of the salinity collection pit structure applicable to low-salinity saline water environments according to the present invention; Figure 7 The graph shows the relationship between the distance and time of saline intrusion when using a saline collection pit in the prior art and when using a segmented saline collection pit of the present invention.

[0020] Explanation of reference numerals in the attached drawings: 1. Lock chamber; 2. Upper approach channel; 3. Salt collection pit structure; 4. Partially deepened structure. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0022] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0023] As attached Figure 1 and attached Figure 2 The diagram shows the existing saline collection pit structure. Saline water enters the upper approach channel 2 through the lock chamber 1. The saline collection pit structure 3 is set along the length of the upper approach channel 2, and its length is basically adapted to the length of the upper approach channel 2. The saline collection pit structure 3 has a huge overall volume, and its bottom is entirely flat. While the existing deep layout of the saline collection pit structure 3 allows the brine to sink into the pit, the brine will infiltrate upstream at a faster rate from the bottom. (See attached diagram.) Figure 3 As shown, under the same time conditions, the salt water in the traditional salt collection pit structure 3 travels farther.

[0024] In response to the movement characteristics of low-salinity saline water in saline collection pit structures, this solution provides a method for preventing salinity in low-salinity saline water environments. It adopts a segmented saline collection pit structure by deepening the pits in multiple localized areas to increase the head loss of saline water flowing upstream. By repeatedly increasing and decreasing the water depth in the segmented saline collection pit structure, the pressure energy at the interface between saline and fresh water is continuously changed, dissipating the kinetic energy of the saline water and slowing down the upstream speed of the saline water.

[0025] Additionally, as attached Figure 4 and attached Figure 5 As shown, this solution also provides a saline pit structure suitable for low salinity saline water environment. The saline pit structure 3 is distributed along the length direction of the upper approach channel 2, and the overall length of the saline pit structure 3 is less than the length of the upper approach channel 2. Multiple local deepening structures 4 are provided on the saline pit structure 3 along the length direction of the upper approach channel 2 so that the saline pit structure 3 as a whole forms a segmented saline pit structure.

[0026] In this embodiment, the length of the salt collection pit structure 3 is 65%-75% of the length of the upper navigation channel 2.

[0027] In this embodiment, the interval length between two adjacent locally deepened structures 4 on the salt collection pit structure 3 is 0.15-0.25 times the length of the upper navigation channel 2. Specifically, the interval length between two adjacent locally deepened structures 4 on the salt collection pit structure 3 is 0.2 times the length of the upper navigation channel 2.

[0028] For example, see appendix. Figure 5 As shown, in this embodiment, the height between the bottom of the partially deepened structure 4 and the bottom of the upper navigation channel 2 is H, and the height between the bottom of the remaining locations of the salt collection pit structure 3 and the bottom of the upper navigation channel 2 is 0.6H.

[0029] For example, see appendix. Figure 5 As shown, in this embodiment, the length of the locally deepened structure 4 is 0.1 times the length of the upper navigation channel 2, and the width of the locally deepened structure 4 is adapted to the width of the upper navigation channel 2.

[0030] In this embodiment, the salt collection pit structure 3 is provided with a first partial deepening structure, a second partial deepening structure, a third partial deepening structure and a fourth partial deepening structure. The first partial deepening structure is located in the middle and upper reaches of the upper navigation channel 2, the second partial deepening structure is located in the middle and lower reaches of the upper navigation channel 2, and the third and fourth partial deepening structures are located at the end of the upper navigation channel 2 (the inlet area of ​​the water conveyance system).

[0031] For example, see appendix. Figure 6 As shown, in this embodiment, the first and second local deepening structures are distributed along the length direction of the upper navigation channel 2 in the fixed section of the upper navigation channel 2, and the third and fourth local deepening structures are distributed along the width direction of the upper navigation channel 2 in the transition section of the upper navigation channel 2.

[0032] For example, see appendix. Figure 6 As shown, in this embodiment, the volume of the first and second local deepening structures is V, and the volume of the third and fourth local deepening structures is V / 3.

[0033] Compared with existing technologies, this invention, based on the traditional layout of saline collection pits, employs multiple locally deepened structures 4 to form a segmented saline collection pit structure. This layout not only increases the head loss of saline water flowing upstream but also continuously changes the pressure energy at the freshwater-saltwater interface by repeatedly and suddenly increasing and decreasing the water depth, further dissipating the kinetic energy of the saline water and significantly slowing down its upstream flow. Combined with the saline drainage facilities located at the bottom of the locally deepened areas, this effectively reduces the amount of saline water accumulated over long-term operation, as shown in the attached diagram. Figure 7 The figure shows the relationship between the intrusion distance and time of saltwater intrusion in the prior art saltwater collection pit and the segmented saltwater collection pit of the present invention. Curve 1 represents the saltwater collection pit of the prior art, and curve 2 represents the segmented saltwater collection pit of the present invention. It can be seen from the curve that the segmented saltwater collection pit structure of the present invention has a shorter intrusion distance in the same amount of time. Under the condition of intrusion distance, the segmented saltwater collection pit structure of the present invention requires a longer time. Therefore, this solution can slow down the speed of saltwater intrusion upstream.

[0034] This invention employs a segmented saline water collection pit structure, utilizing the stratification phenomenon created by the density difference between fresh and salt water. Through segmented and locally deepened design, it significantly reduces the rate of saline water intrusion while drastically decreasing the area and volume of the collection pit. In comparison, the area of ​​the collection pit in this invention is only about 70% of that of the upstream navigation channel 2, far smaller than that of a traditional collection pit. The excavation volume is also much smaller than that of a collection pit of the same area and overall depth. This invention can slow down the rate and salinity of upstream saline water intrusion, reduce the volume of the collection pit, save engineering costs, and avoid the adverse effects of unfavorable water flow on navigation safety.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A salinity collection pit structure suitable for low-salinity saline water environments, characterized in that, A segmented saline collection pit structure is formed by deepening the saline collection pits in multiple local areas to increase the head loss of saline water flowing upstream. The pressure energy at the interface between saline and fresh water is continuously changed by repeatedly increasing and decreasing the water depth of the segmented saline collection pit structure, which dissipates the kinetic energy of the saline water and slows down the speed of saline water flowing upstream. The salt collection pit structure is distributed along the length of the upper approach channel, and the overall length of the salt collection pit structure is less than the length of the upper approach channel. Multiple local deepening structures are provided on the salt collection pit structure along the length of the upper approach channel so that the salt collection pit structure as a whole forms a segmented salt collection pit structure. The length of the salt collection pit structure is 65%-75% of the length of the upper navigation channel; The salt collection pit structure is provided with a first partial deepening structure, a second partial deepening structure, a third partial deepening structure and a fourth partial deepening structure. The first partial deepening structure is located in the middle and upper reaches of the upper navigation channel, the second partial deepening structure is located in the middle and lower reaches of the upper navigation channel, and the third and fourth partial deepening structures are located at the downstream end of the upper navigation channel. The first and second partial deepening structures are distributed along the length of the upper approach channel in a fixed section, while the third and fourth partial deepening structures are distributed along the width of the upper approach channel in a transitional section.

2. The salinity collection pit structure suitable for low-salinity saline water environments according to claim 1, characterized in that, The interval length between two adjacent locally deepened structures on the salt collection pit structure is 0.15-0.25 times the length of the upper navigation channel.

3. The salinity collection pit structure suitable for low-salinity saline water environments according to claim 2, characterized in that, The interval between two adjacent locally deepened structures on the salt collection pit structure is 0.2 times the length of the upper navigation channel.

4. The salinity collection pit structure suitable for low-salinity saline water environments according to claim 1, characterized in that, The height between the bottom of the partially deepened structure and the bottom of the upper approach channel is H, and the height between the bottom of the remaining locations of the salt collection pit structure and the bottom of the upper approach channel is 0.6H.

5. The salinity collection pit structure suitable for low-salinity saline water environments according to claim 1, characterized in that, The length of the locally deepened structure is 0.1 times the length of the upper navigation channel, and the width of the locally deepened structure is adapted to the width of the upper navigation channel.

6. The salinity collection pit structure suitable for low-salinity saline water environments according to claim 1, characterized in that, The volume of the first and second locally deepened structures is V, and the volume of the third and fourth locally deepened structures is V / 3.

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