Double-line ship lock mutual charging and mutual discharging method for improving water saving rate and double-line ship lock

Abstract

The invention belongs to the field of water transportation engineering, and particularly provides a double-line ship lock mutual charging and mutual discharging method for improving the water saving rate, which comprises the following steps that two adjacent line ship locks are respectively a downlink ship lock and an uplink ship lock, and double-line synchronous gate entering is carried out; water in the lock chamber of the downstream ship lock is discharged to the lock chamber of the upstream ship lock until the water level of the lock chamber of the downstream ship lock is flush with the downstream approach channel, and at the moment, the water level of the lock chamber of the upstream ship lock is flush with the water level of the upstream approach channel; double-wire synchronous gate-out is carried out; after the lockage is completed, the double-wire function is automatically switched; and the new round of ship enters according to the switched route, and the operation is repeated. According to the method, the water-saving rate of the ship lock is further improved on the premise that the structural complexity, the maintenance difficulty and the economic cost are not increased.

Description

Technical Field

[0001] The present invention belongs to the field of water transport engineering, and in particular relates to a double-line ship lock mutual charging and discharging method for improving water saving rate and a double-line ship lock. Background Art

[0002] Locks, crucial for overcoming water level differences in navigation channels, consume significant amounts of water during operation. Each time a ship passes through a traditional lock, tens of thousands of cubic meters of water must be discharged downstream. This depletion of water resources is particularly significant in arid regions or in canal cascades. In recent years, with the advancement of green shipping concepts, water-saving lock technology has become a research hotspot.

[0003] Existing technologies can be broadly categorized into the following: First, additional water storage tanks are installed on either side or at the bottom of the lock chamber. When the lock chamber is released, some water is temporarily stored in the tanks, to be reused upon the next refill. For example, CN110042820A describes a dual-line interlocking ship lock with a shared water reservoir. However, this technology has limited storage capacity, resulting in a low water-saving rate and requiring additional structure. Second, the installation of auxiliary locks or reservoirs adjacent to the lock significantly improves water-saving rates, but faces challenges such as land acquisition difficulties and high costs. Third, a combined lock and pump approach is employed. For example, CN111962489A describes a multi-stage water-saving tank-based water-saving ship lock power generation and recharge system. This system utilizes the water released from the water-saving tanks to generate electricity, consuming the energy to re-pump the released water upstream. However, this secondary energy recovery approach suffers from low efficiency and economic efficiency. Overall, existing technologies suffer from common issues such as a conflict between water-saving efficiency and structural complexity, high costs, and difficulty maintaining maintenance.

[0004] To address the limitations of existing dual-line shiplock interlocking charging and discharging technologies, including limited water savings, long charging and discharging times, and low water allocation efficiency under asymmetric lock conditions, this paper proposes a dual-line shiplock interlocking charging and discharging method that improves water savings. By collaboratively controlling a variable-frequency bidirectional pump and interlocking charging and discharging corridors, this method achieves water savings exceeding 90% while reducing charging and discharging times by over 20%, without requiring additional large-scale water storage facilities or complex pipelines. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a double-line ship lock mutual charging and discharging method and a double-line ship lock that improve the water saving rate, so as to further improve the water saving rate of the ship lock without increasing the structural complexity, maintenance difficulty and economic cost.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for mutual charging and discharging of a double-line ship lock to improve the water saving rate, comprising the following steps: Step 1: Double-line synchronous gate entry: The two adjacent lines of ship locks are the downstream ship lock and the upstream ship lock respectively; Downstream line: Water from the upstream reservoir is injected into the downstream lock chamber through the water transfer corridor corresponding to the bottom of the downstream lock. When the water level in the downstream lock chamber is flush with that in the upstream, the miter gate corresponding to the upper lock of the downstream lock is opened, and upstream ships enter the downstream lock; Upward line: The water in the upstream lock chamber flows into the downstream pilot channel through the corresponding water transfer corridor at the bottom. When the water level in the upstream lock chamber is flush with that in the downstream, the miter gate of the upstream lock is opened, and downstream ships enter the upstream lock; Step 2: Mutual filling and draining between the lock chambers of two adjacent lines of ship locks: After the miter gates corresponding to the two-line ship locks are closed, the water in the lock chamber of the downstream ship lock is discharged to the lock chamber of the upstream ship lock until the water level in the lock chamber of the downstream ship lock is flush with the downstream pilot channel. At this time, the water level in the lock chamber of the upstream ship lock is flush with the upstream pilot channel, and the discharge stops; Step 3: Double-line synchronous exit: Upward line: The corresponding miter gate of the upward direction ship lock opens, and the ship leaves the lock and goes up; Downward line: The corresponding miter gate of the downstream lock is opened, and the ship exits the lock and goes downward; Step 4: Switch between uplink and downlink routes: After completing the lock, the dual-line function will be automatically switched: the original upward direction lock will be switched to the downward direction lock, and the original downward direction lock will be switched to the upward direction lock; After the previous round of passing through the lock is completed, a new round of ships enters according to the switched route. At this time, the original downstream line becomes the upstream line, and its water level is flush with the water level of the downstream pilot channel, which allows downstream ships to enter the lock directly; the original upstream line becomes the downstream line, and its water level is flush with the water level of the upstream pilot channel, which allows upstream ships to enter the lock directly. After entering the lock, repeat steps 2 to 4.

[0007] In a preferred solution, the lock chambers of the two adjacent ship locks are connected via a mutual charging and discharging gallery, and the mutual charging and discharging gallery is provided with a mutual charging and discharging gallery valve and a variable frequency bidirectional pump.

[0008] In a preferred solution, the mutual filling and draining between the lock chambers of the two adjacent lines of ship locks in step 2 includes the following two parts: S201, adjacent lock chambers charge and discharge water to offset each other: After the miter gates corresponding to the downstream and upstream ship locks are closed, the valves of the mutual charging and discharging corridors are opened, the mutual charging and discharging corridors connecting the downstream and upstream ship locks are opened, and the water levels of the lock chambers of the downstream and upstream ship locks gradually approach each other; S202, variable frequency bidirectional pump forced drainage: When the water levels in the lock chambers of the adjacent downstream and upstream ship locks approach or the flow rate in the mutual charging and discharging corridor is less than the set value, the variable frequency two-way pump in the mutual charging and discharging corridor is turned on to forcibly discharge the water in the lock chamber of the downstream ship lock into the lock chamber of the upstream ship lock until the water level in the lock chamber of the downstream ship lock is flush with the water level in the downstream pilot channel. At this time, the water level in the lock chamber of the upstream ship lock is flush with the water level in the upstream pilot channel, and the variable frequency two-way pump and the valve in the mutual charging and discharging corridor are closed.

[0009] In a preferred solution, in step 2, when asymmetric lock chambers appear in the adjacent two-line ship locks, if the downstream ship lock is a large lock chamber and the upstream ship lock is a small lock chamber, when the large lock chamber drains water into the small lock chamber until the water level in the small lock chamber is flush with the water level in the upstream pilot channel, at this time, the water level in the large lock chamber is still higher than the water level in the downstream pilot channel, and the water in the large lock chamber is discharged to the downstream pilot channel through the water transfer corridor corresponding to the bottom of the large lock chamber until the water level in the large lock chamber is flush with the water level in the downstream; When the upstream and downstream routes are switched, the downstream lock is the small lock chamber and the upstream lock is the large lock chamber. When the small lock chamber drains water to the large lock chamber until the water level in the small lock chamber is flush with the water level in the downstream pilot channel, the water level in the large lock chamber is still lower than the water level in the upstream pilot channel. The water from the upstream reservoir is injected into the large lock chamber through the corresponding water transfer corridor at the bottom of the large lock chamber until the large lock chamber is flush with the upstream water level.

[0010] In a preferred solution, a water transfer gallery is provided at the bottom of the two adjacent lines of ship locks, which is used to transfer water in the lock chamber of the ship lock to the downstream or downstream, or to transfer water from the downstream or downstream to the lock chamber of the ship lock.

[0011] In a preferred solution, the bottoms of the two adjacent ship locks are provided with a plurality of water inlets connected to the water transfer corridor, and the water inlets are provided with energy dissipation covers.

[0012] In a preferred solution, each group of mutual charging and discharging corridors is provided with a two-line mutual charging and discharging corridor valve, and the two-line mutual charging and discharging corridor valves are arranged at both ends of the variable frequency bidirectional pump.

[0013] In a preferred solution, energy dissipation grids are provided at both ends of the mutual charging and discharging corridor.

[0014] The present invention also provides a double-line ship lock that improves the water-saving rate. The double-line ship lock adopts the above-mentioned mutual charging and discharging method for passing ships, including two adjacent line ship locks, the two line ship locks are respectively a downstream direction ship lock and an upstream direction ship lock, the downstream direction lock and the upstream direction lock can switch between upstream and downstream routes, the bottom of the two adjacent line ship locks are provided with a water transfer corridor, the lock chambers of the two adjacent line ship locks are connected by a mutual charging and discharging corridor, and the mutual charging and discharging corridor is provided with a mutual charging and discharging corridor valve and a variable frequency bidirectional pump.

[0015] In a preferred solution, the bottoms of the two adjacent ship locks are provided with a plurality of water inlets connected to the water transfer corridor, and the water inlets are provided with energy dissipation covers; and energy dissipation grids are provided at both ends of the mutual charging and discharging corridor.

[0016] The present invention provides a method for mutual charging and discharging of a double-line ship lock and a double-line ship lock for improving water saving rate, which has the following beneficial effects: 1. This system realizes the recycling of water in the lock chambers through the mutual filling and draining of adjacent lock chambers and forced drainage by variable frequency bidirectional pumps. The water saving rate exceeds 90%, significantly reducing the consumption of downstream water resources. It is especially suitable for arid areas or cascade ship lock scenarios.

[0017] 2. The dual-line synchronous operation and automatic route switching function supports two-way ship passing on a single-line channel. Compared with the traditional single-line one-way ship lock, the navigation capacity is doubled to meet the needs of high-volume shipping.

[0018] 3. There is no need to add large-scale water storage facilities or complex pipelines. It only connects the existing water transmission corridor with the mutual charging and discharge corridor. The structure is low in complexity, and the construction and maintenance costs are significantly lower than traditional water-saving technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and examples: Figure 1 A schematic diagram of a method for mutual charging and discharging of a double-line ship lock to improve water conservation rate; Figure 2 This is an overall schematic diagram of a mutual charging and discharging ship lock that improves water saving rate; Figure 3 This is a schematic diagram of water level changes due to mutual charging and discharging; Figure 4 Schematic diagram of water level changes under special working conditions; Figure 5 This is a schematic diagram of water level changes after switching up and down routes under special working conditions; In the figure: downstream ship lock 1, upstream ship lock 2, water transfer corridor 3, mutual charging and discharging corridor 4, mutual charging and discharging corridor valve 5, variable frequency bidirectional pump 6, energy dissipation cover plate 7, energy dissipation grid plate 8, upper lock head miter gate 9, lower lock head miter gate 10, upstream reservoir 11, downstream pilot channel 12. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] Example 1: like Figure 1As shown, the present invention provides a double-line ship lock for improving water saving rate, comprising two adjacent line ship locks, the two line ship locks being a downstream direction ship lock 1 and an upstream direction ship lock 2, an upper lock head miter gate 9 being arranged near the upstream reservoir end in the downstream direction ship lock 1 and the upstream direction ship lock 2, and a lower lock head miter gate 10 being arranged near the downstream pilot channel.

[0022] A water transfer corridor 3 is provided at the bottom of each of the two adjacent ship locks, used to transfer water from the lock chamber to the downstream or downstream, or vice versa. The lock chambers of the two adjacent ship locks are formed by excavation and concrete pouring, with the water transfer corridor 3 located below the lock chamber floor. The water filling and discharge capacity of the water transfer corridor 3 meets the hydraulic index and time requirements for the lock chamber filling and discharge.

[0023] The bottoms of the two adjacent ship locks are both provided with a plurality of water inlets connected to the water delivery corridor 3 , and energy dissipation cover plates 7 are provided at the water inlets.

[0024] The downstream lock 1 and the upstream lock 2 can switch between upstream and downstream routes to meet the two-way passage of ships in a single-line channel, which improves the navigation capacity compared with ordinary single-line one-way locks.

[0025] The lock chambers of two adjacent ship locks are connected by a mutual charging and discharging gallery 4, which is equipped with a mutual charging and discharging gallery valve 5 and a variable frequency bidirectional pump 6. Energy dissipation grids 8 are provided at both ends of the mutual charging and discharging gallery 4. Each set of mutual charging and discharging galleries 4 is equipped with two-line mutual charging and discharging gallery valves 5, which are arranged at both ends of the variable frequency bidirectional pump 6. When one of the valves fails, it is lifted for maintenance, and the other valve can still ensure mutual charging and discharging and forced drainage; the valves at both ends also serve as maintenance doors, and the bidirectional pump can be inspected when both are closed. The variable frequency bidirectional pump can automatically adjust the frequency according to pressure changes to maintain a constant pressure of the water flow in the forced discharge gallery, and the pump operating water level is lower than the lowest operating water level of the ship lock.

[0026] Example 2: A method for mutual charging and discharging of double-line ship locks to improve water saving rate, such as Figure 1 As shown, the following steps are included: Step 1: Double-line synchronous gate entry: The two adjacent ship locks are the downstream ship lock and the upstream ship lock, and the lock chambers of the downstream ship lock and the upstream ship lock are the same size. Figure 2 In the middle, the left side is the downstream lock, and the right side is the upstream lock.

[0027] Downstream line: Water from the upstream reservoir is injected into the downstream ship lock chamber through the water transfer corridor corresponding to the bottom of the downstream ship lock. When the water level in the downstream ship lock chamber is flush with that in the upstream, the miter gate corresponding to the upper lock of the downstream ship lock is opened, and upstream ships enter the downstream ship lock.

[0028] Upstream line: The water in the upstream lock chamber flows into the downstream pilot channel through the corresponding water transfer corridor at its bottom. When the water level in the upstream lock chamber is flush with that in the downstream, the miter gate at the lower end of the upstream lock is opened, and downstream ships enter the upstream lock.

[0029] Step 2: Mutual filling and draining between the lock chambers of two adjacent lines of ship locks: After the miter gates corresponding to the two-line ship locks are closed, the miter gates include the upper miter gate and the lower miter gate. The water in the lock chamber of the downstream ship lock is discharged to the lock chamber of the upstream ship lock until the water level in the lock chamber of the downstream ship lock is flush with the downstream pilot channel. At this time, the water level in the lock chamber of the upstream ship lock is flush with the upstream pilot channel, and the discharge is stopped.

[0030] The specific steps include: S201, adjacent lock chambers charge and discharge water to offset each other: After the miter gates corresponding to the downstream and upstream ship locks are closed, the valves of the mutual charging and discharging corridors are opened, and the mutual charging and discharging corridors connecting the downstream and upstream ship locks are opened, and the water levels of the lock chambers of the downstream and upstream ship locks gradually approach each other. Figure 3 As shown in the figure above, the double-line lock chamber forms a communicating vessel, which charges and discharges each other to transfer the downstream water to the upstream ship lock, thus achieving the water-saving effect of the ship lock.

[0031] S202, variable frequency bidirectional pump forced drainage: When the water levels in the lock chambers of the adjacent downstream and upstream ship locks approach or the flow in the mutual charging and discharging corridor is less than the set value, the variable frequency bidirectional pump in the mutual charging and discharging corridor is turned on to forcibly discharge the water in the lock chamber of the downstream ship lock into the lock chamber of the upstream ship lock.

[0032] The water level in the downstream lock gradually decreases until it is flush with the downstream pilot channel water level. At this time, the water level in the upstream lock is flush with the upstream pilot channel water level. The water level changes as follows: Figure 3 As shown in the figure below, close the variable frequency bidirectional pump and the mutual charging and discharging gallery valves.

[0033] Step 3: Double-line synchronous exit: Upward line: The corresponding miter gate of the upper lock is opened in the upward direction, and the ship exits the lock and goes up.

[0034] Downward line: The corresponding miter gate of the downstream lock is opened, and the ship exits the lock and goes downward.

[0035] Step 4: Switch between uplink and downlink routes: After completing the lock passage, the dual-lane function automatically switches: the original upstream lock switches to the downstream lock, and the original downstream lock switches to the upstream lock. A new round of ships enters along the switched route. The original downstream lane now becomes the upstream lane, its water level aligned with the downstream pilot channel, allowing downstream ships to enter the locks directly. The original upstream lane now becomes the downstream lane, its water level aligned with the upstream pilot channel, allowing upstream ships to enter the locks directly. After entering the lock, repeat steps 2 through 4.

[0036] Example 3: Different from Example 2, when the adjacent two-line ship locks have asymmetric ship lock chambers, the operation process of step 2 is as follows: If the downstream lock is a large lock chamber and the upstream lock is a small lock chamber, Figure 4 As shown, the left side is the large lock chamber and the right side is the small lock chamber. When the large lock chamber (downstream ship lock) discharges water to the small lock chamber (upstream ship lock) until the water level in the small lock chamber is flush with the water level in the upstream pilot channel, at this time, the water level in the large lock chamber is still higher than the water level in the downstream pilot channel. The water in the large lock chamber is discharged to the downstream pilot channel through the corresponding water transfer gallery at the bottom of the large lock chamber until the water level in the large lock chamber is flush with the downstream water level. When the up and down routes are switched, the small lock chamber switches to the down direction lock and the large lock chamber switches to the up direction lock. Figure 5 As shown, the large lock chamber is on the left and the small lock chamber is on the right. When the small lock chamber (downstream ship lock) drains water to the large lock chamber (upstream ship lock) until the water level in the small lock chamber is flush with the water level in the downstream navigation channel, the water level in the large lock chamber is still lower than the water level in the upstream navigation channel. The water from the upstream reservoir is injected into the large lock chamber through the corresponding water transfer corridor at the bottom of the large lock chamber until the large lock chamber is flush with the upstream water level.

[0037] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for mutual charging and discharging of a double-line ship lock to improve water saving rate, characterized in that: The following steps are involved: Step 1: Double-line synchronous gate entry: The two adjacent lines of ship locks are the downstream ship lock and the upstream ship lock respectively; Downstream line: Water from the upstream reservoir is injected into the downstream lock chamber through the water transfer corridor corresponding to the bottom of the downstream lock. When the water level in the downstream lock chamber is flush with that in the upstream, the miter gate corresponding to the upper lock of the downstream lock is opened, and upstream ships enter the downstream lock; Upward line: The water in the upstream lock chamber flows into the downstream pilot channel through the corresponding water transfer corridor at the bottom. When the water level in the upstream lock chamber is flush with that in the downstream, the miter gate of the upstream lock is opened, and downstream ships enter the upstream lock; Step 2: Mutual filling and draining between the lock chambers of two adjacent lines of ship locks: After the miter gates at the head of the two-line ship lock are closed, the water in the lock chamber of the downstream ship lock is discharged into the lock chamber of the upstream ship lock until the water level in the lock chamber of the downstream ship lock is flush with the downstream pilot channel. At this time, the water level in the lock chamber of the upstream ship lock is flush with the upstream pilot channel, and the discharge stops; Step 3: Double-line synchronous exit: Upward line: The corresponding miter gate of the upward direction ship lock opens, and the ship leaves the lock and goes up; Downward line: The corresponding miter gate of the downstream lock is opened, and the ship exits the lock and goes downward; Step 4: Switch between uplink and downlink routes: After completing the lock, the dual-line function will be automatically switched: the original upward direction lock will be switched to the downward direction lock, and the original downward direction lock will be switched to the upward direction lock; A new round of ships enters according to the switched route and repeats steps one to four.

2. A method for mutual charging and draining of a double-line ship lock to improve water saving rate according to claim 1, characterized in that: The lock chambers of the two adjacent ship locks are connected through a mutual charging and discharging corridor, and the mutual charging and discharging corridor is provided with a mutual charging and discharging corridor valve and a variable frequency bidirectional pump.

3. A method for mutual charging and draining of a double-line ship lock to improve water saving rate according to claim 2, characterized in that: The mutual filling and draining between the lock chambers of the two adjacent lines of ship locks in step 2 includes the following two parts: S201, adjacent lock chambers charge and discharge water to offset each other: After the miter gates corresponding to the downstream and upstream ship locks are closed, the valves of the mutual charging and discharging corridors are opened, and the mutual charging and discharging corridors connecting the downstream and upstream ship locks are opened, so that the water levels of the lock chambers of the downstream and upstream ship locks gradually approach each other; S202, variable frequency bidirectional pump forced drainage: When the water levels in the lock chambers of the adjacent downstream and upstream ship locks approach or the flow rate in the mutual charging and discharging corridor is less than the set value, the variable frequency two-way pump in the mutual charging and discharging corridor is turned on to forcibly discharge the water in the lock chamber of the downstream ship lock into the lock chamber of the upstream ship lock until the water level in the lock chamber of the downstream ship lock is flush with the water level in the downstream pilot channel. At this time, the water level in the lock chamber of the upstream ship lock is flush with the water level in the upstream pilot channel, and the variable frequency two-way pump and the valve in the mutual charging and discharging corridor are closed.

4. A method for mutual charging and draining of a double-line ship lock to improve water saving rate according to claim 1, characterized in that: In step 2, when asymmetric lock chambers appear in the two adjacent ship locks, if the downstream ship lock is a large lock chamber and the upstream ship lock is a small lock chamber, when the large lock chamber drains water into the small lock chamber until the water level in the small lock chamber is flush with the water level in the upstream pilot channel, at this time, the water level in the large lock chamber is still higher than the water level in the downstream pilot channel, and the water in the large lock chamber is discharged to the downstream pilot channel through the water transfer corridor corresponding to the bottom of the large lock chamber until the water level in the large lock chamber is flush with the water level in the downstream; When the upstream and downstream routes are switched, the downstream lock is the small lock chamber and the upstream lock is the large lock chamber. When the small lock chamber drains water to the large lock chamber until the water level in the small lock chamber is flush with the water level in the downstream pilot channel, the water level in the large lock chamber is still lower than the water level in the upstream pilot channel. The water from the upstream reservoir is injected into the large lock chamber through the corresponding water transfer corridor at the bottom of the large lock chamber until the large lock chamber is flush with the upstream water level.

5. A method for mutual charging and draining of a double-line ship lock to improve water saving rate according to claim 1, characterized in that: The bottoms of the two adjacent lines of ship locks are both provided with water transfer corridors for transferring water from the lock chamber of the ship lock to the downstream or downstream, or transferring water from the downstream or downstream to the lock chamber of the ship lock.

6. A method for mutual charging and draining of a double-line ship lock to improve water conservation according to claim 5, characterized in that: The bottoms of the two adjacent ship locks are both provided with a plurality of water inlets connected to the water delivery corridor, and the water inlets are provided with energy dissipation covers.

7. A method for mutual charging and draining of a double-line ship lock to improve water conservation according to claim 2, characterized in that: Each group of mutual charging and discharging corridors is provided with two-line mutual charging and discharging corridor valves, and the two-line mutual charging and discharging corridor valves are arranged at both ends of the variable frequency bidirectional pump.

8. A method for mutual charging and draining of a double-line ship lock to improve water conservation according to claim 2, characterized in that: Energy dissipation grids are provided at both ends of the mutual charging and discharging corridor.

9. A double-line ship lock with improved water saving rate, characterized in that: The method for mutual charging and discharging of double-line locks according to any one of claims 1 to 8 is adopted for passing ships, comprising two adjacent line locks, the two line locks being respectively a downstream direction lock and an upstream direction lock, the downstream direction lock and the upstream direction lock being capable of switching between upstream and downstream routes, a water transfer gallery being provided at the bottom of the two adjacent line locks, the lock chambers of the two adjacent line locks being connected by a mutual charging and discharging gallery, and a mutual charging and discharging gallery valve and a variable frequency bidirectional pump being provided on the mutual charging and discharging gallery.

10. A double-line ship lock for improving water saving rate according to claim 9, characterized in that: The bottoms of the two adjacent ship locks are provided with a plurality of water inlets connected to the water delivery corridor, and the water inlets are provided with energy dissipation covers; energy dissipation grids are provided at both ends of the mutual charging and discharging corridor.

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