Construction method of water supply system based on degree flood and guarantee water supply node

Abstract

This invention provides a construction method for a water supply system based on flood control and water supply node protection, comprising the following steps: S1, constructing a first cofferdam downstream of the water supply canal, constructing a second cofferdam upstream of the water supply canal, constructing a seepage intercepting wall around the pumping station, and constructing a diversion channel connecting the water supply canal and the drainage canal; S2, constructing the pumping station outlet canal, the control intake canal, the pumping station foundation pit, and the control gate foundation pit; S3, constructing a third cofferdam at the inlet of the control intake canal, and constructing a fourth cofferdam in the intermediate canal to block the pumping station inlet and the booster station inlet; S4, after the third and fourth cofferdams are completed, dismantling the first cofferdam; S5, dismantling the second, third, and fourth cofferdams. The beneficial effects of this invention are: multiple cofferdams are constructed in stages according to node and construction requirements, acting simultaneously or separately in stages, ensuring that different sub-projects within the area are constructed synchronously according to the schedule, thereby ensuring the normal use of existing water supply lines such as the booster station.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy construction technology, and in particular relates to a construction method for a water supply system based on flood control and water supply guarantee nodes. Background Technology

[0002] During water conservancy construction, situations arise where a water supply canal already has a booster station drawing water, necessitating the addition of a drainage canal. The current construction method involves building cofferdams upstream of the drainage canal and downstream of the water supply canal, followed by the construction of the pumping station. This method has the following problems: First, the traditional construction method has a long construction period, and the booster station may be unable to supply water normally during construction, affecting the booster station's water supply lines. Second, the construction process may coincide with the flood season, causing the water level within the construction area to rise, which will affect the construction progress and, in severe cases, lead to flooding. Summary of the Invention

[0003] In view of this, the present invention aims to propose a construction method for a water supply system based on flood control and water supply node protection, in order to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A construction method for a water supply system based on flood control and water supply guarantee nodes includes the following steps:

[0006] S1. Construct the first cofferdam downstream of the water supply canal, construct the second cofferdam upstream of the water supply canal, construct cutoff walls around the pumping station, and construct a diversion channel to connect the water supply canal and the drainage canal.

[0007] S2. Construct the pump station outlet canal, the control inlet canal, the foundation pit of the pump station, and the foundation pit of the control gate. The outlet end of the pump station outlet canal and the control inlet canal are blocked from the water supply canal by a second cofferdam. The inlet end of the control inlet canal is connected to the intermediate canal. The intermediate canal and the water supply canal are blocked from each other by a first cofferdam.

[0008] S3. After the control water intake channel is completed, a third cofferdam is built at the inlet of the control water intake channel, and a fourth cofferdam is built in the middle channel to block the water inlet of the pumping station and the water inlet of the booster station.

[0009] After the construction of S4, the third cofferdam and the fourth cofferdam is completed, the first cofferdam will be demolished.

[0010] After the construction of S5, the pumping station, and the control gate is completed, the second, third, and fourth cofferdams will be dismantled.

[0011] Furthermore, in step S3, a fifth cofferdam is constructed at the outlet of the pump station's outlet channel, and the height of the fifth cofferdam is higher than that of the second cofferdam.

[0012] Furthermore, a continuous high-pressure jet grouting curtain is installed around the foundation pit of the pumping station, and the centerline of the fourth cofferdam coincides with the seepage cutoff wall.

[0013] Furthermore, geomembranes were laid on the bottom and slope of the first, second, third, and fourth cofferdams before their construction.

[0014] Furthermore, the third and fourth cofferdams were constructed using heavy silty clay excavated from the control gate pit and pump station pit, respectively. After the third and fourth cofferdams were constructed, geotextile was laid on the water-facing side.

[0015] Furthermore, in the event of a once-in-20-year flood disaster during construction, the fifth cofferdam will be dismantled, allowing the floodwater to be discharged directly through the pumping station foundation pit.

[0016] Furthermore, before constructing the third cofferdam, the upper end of the high-pressure jet grouting cutoff wall was modified into an inverted trapezoidal cross-section flush with the bottom and slope protection of the intermediate channel, and heavy silty clay was used for layered filling and compaction.

[0017] Furthermore, the bottom elevation of the diversion channel is higher than the bottom elevation of the control inlet channel, and the bottom elevation of the control inlet channel is higher than the bottom elevation of the pump station outlet channel.

[0018] Compared with existing technologies, the construction method of a water supply system based on flood control and water supply node protection described in this invention has the following advantages:

[0019] (1) The construction method of the water supply system based on flood control and water supply node protection described in this invention involves multiple cofferdams being filled in stages according to the node and construction requirements, and acting simultaneously or separately in stages to ensure that different sub-projects in the area are constructed in sync according to the schedule plan, ensuring the node construction period, and thus ensuring the normal use of the original water supply lines such as the booster station.

[0020] (2) The construction method of the water supply system based on flood control and water supply node protection described in this invention has multiple cofferdams acting in stages, which can ensure the drainage and flood control needs of upstream residents and farmland in the direction of flood discharge, while ensuring the continuous construction of buildings and structures in each node within the construction area. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a schematic diagram of the construction structure of the water supply system according to an embodiment of the present invention;

[0023] Figure 2This is a schematic diagram of the cross-sectional structure of the water intake channel according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the cross-sectional structure of the fourth cofferdam according to an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. First cofferdam; 2. Second cofferdam; 3. Third cofferdam; 4. Fourth cofferdam; 5. Fifth cofferdam; 6. Intermediate canal; 7. Pump station outlet canal; 8. Control intake canal; 9. Drainage canal; 10. Control gate; 11. Pump station; 12. Booster station; 13. Water supply canal. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] like Figure 1 As shown, a construction method for a water supply system based on flood control and water supply guarantee nodes includes the following steps:

[0030] S1. Construct a first cofferdam 1 downstream of the water supply canal 13, construct a second cofferdam 2 upstream of the water supply canal 13, construct an intercepting wall around the pump station 11, and construct a diversion channel to connect the water supply canal 13 and the drainage canal 9. The diversion channel serves as a temporary diversion measure during the non-flood season, allowing upstream rainwater to be diverted downstream through the diversion channel.

[0031] S2. Construct the foundation pits for the pump station outlet channel 7, the control inlet channel 8, the pump station 11, and the control gate 10. The outlet ends of the pump station outlet channel 7 and the control inlet channel 8 are blocked from the water supply channel 13 by a second cofferdam 2. The inlet end of the control inlet channel 8 is connected to the intermediate channel 6. The intermediate channel 6 is blocked from the water supply channel 13 by a first cofferdam 1. The channel excavation, bottom protection, slope protection, pump station 11 foundation pit, and control gate 10 foundation pit are constructed simultaneously and in parallel within the construction area.

[0032] S3. After the completion of the controlled intake channel 8, a third cofferdam 3 is constructed at the inlet of the controlled intake channel 8, and a fourth cofferdam 4 is constructed in the intermediate channel 6 to block the inlet of pump station 11 and the inlet of booster station 12. Before the construction of the fourth cofferdam 4, the channel at the bottom of the fourth cofferdam 4 is excavated, reinforced with concrete, tamped, and sloped. During the excavation of the channel in the area of ​​the fourth cofferdam 4, care must be taken to avoid damaging the completed cutoff wall. At this point, the channel construction within the closed loop of the second cofferdam 2, the third cofferdam 3, the fourth cofferdam 4, booster station 12, and Longde station has been completed to ensure that this area has the conditions for water flow.

[0033] After the construction of S4, the third cofferdam 3, and the fourth cofferdam 4 is completed, the first cofferdam 1 is demolished; the river water in the water supply canal 13 reaches the inlet of the booster station 12 through the area of ​​the demolished first cofferdam 1. The second cofferdam 2, the third cofferdam 3, and the fourth cofferdam 4 work together to block water and provide a dry working environment for the main structure of the pump station 11, the pump station outlet canal 7, the main structure of the control gate 10, and the inlet and outlet canals of the control gate 10.

[0034] After the completion of S5, pump station 11, and control gate 10, the second cofferdam 2, the third cofferdam 3, and the fourth cofferdam 4 will be demolished.

[0035] In step S3, a fifth cofferdam 5 is constructed at the outlet of the pump station's outlet channel 7, and the height of the fifth cofferdam 5 is higher than that of the second cofferdam 2.

[0036] The foundation pit of the pump station 11 is surrounded by a continuous high-pressure jet grouting curtain, and the center line of the fourth cofferdam 4 coincides with the seepage cutoff wall.

[0037] Before constructing the first cofferdam 1, the second cofferdam 2, the third cofferdam 3, the fourth cofferdam 4, and the fifth cofferdam 5, geomembranes were laid on the bottom and slope protection. This facilitated the later dismantling and cleaning of the cofferdams.

[0038] The third cofferdam 3 and the fourth cofferdam 4 were constructed using heavy silty clay excavated from the foundation pit of the control gate 10 and the foundation pit of the pump station 11, respectively. After the third cofferdam 3 and the fourth cofferdam 4 were constructed, geotextile was laid on the water-facing side.

[0039] When the construction process was affected by a once-in-20-year flood, the fifth cofferdam 5 was demolished, allowing the floodwater to be discharged directly through the foundation pit of pumping station 11.

[0040] Before constructing the third cofferdam 3, the upper end of the high-pressure jet grouting cutoff wall was shaped into an inverted trapezoidal cross-section flush with the bottom and slope protection of the intermediate channel 6, and layered filling and compaction were carried out using heavy silty clay. The water head difference between the two sides of the fourth cofferdam 4 is about 10 meters, and the geology of this area is mostly fine sand with good permeability, which easily leads to seepage around the cofferdam. The fourth cofferdam 4 was built on top of the high-pressure jet grouting cutoff wall of pump station 11. Before filling, the jet grouting wall was shaped into an inverted trapezoidal cross-section flush with the bottom and slope protection of the completed channel, and the center of the cofferdam coincided with it. Layered filling and compaction of heavy silty clay were carried out to ensure that the filled cofferdam could resist the difference in water level between the inside and outside and prevent leakage, thus providing a dry working environment for the foundation pit.

[0041] The bottom elevation of the diversion channel is higher than that of the control intake channel 8, and the bottom elevation of the control intake channel 8 is higher than that of the pump station outlet channel 7. The bottom elevation of the diversion channel is 28 meters, the bottom elevation of the control intake channel 8 is 27.5 meters, and the bottom elevation of the pump station outlet channel 7 is 23.5 meters. The diversion at each stage is controlled by the overflow principle and the combination of various cofferdams.

[0042] Phased traffic diversion method

[0043] The first phase of construction during the non-flood season will involve normal diversion through open channels until May 30th, when the bottom protection of each channel, some slope protection, and the bottom slab of pump station 11 will be completed.

[0044] In the second phase, after May 30, 2020, when the flood season water level is less than once in 10 years, the construction of the main body of pump station 11 and control gate 10 will be carried out by diverting the flow through a diversion channel.

[0045] During the third stage of the flood season, when the flood event is greater than once in 10 years but less than once in 20 years, the control gate 10 is used for diversion. In addition to evacuating people and machinery from the foundation pit to the shore and ensuring their safety, it is also necessary to ensure the safety of the structures under construction in the foundation pit. Therefore, in order to reduce the difference in water head between the inside and outside, it is advisable to consider emergency water filling into the foundation pit.

[0046] In the fourth stage, when encountering water levels exceeding a 20-year return period, all cofferdams will be dismantled to prioritize the safety of people's lives and property in the surrounding areas. Flood discharge will be carried out through three cross-sections: the Longde Pumping Station 11 water passage, the Longde Control Gate 10 water passage, and the diversion channel.

[0047] After the flood season ends, the water in the foundation pit will be pumped into the diversion channel, and the bottom and slopes of the foundation pit that have been soaked will be excavated and backfilled to the top elevation of the foundation of pump station 11.

[0048] The diversion channel is located on the southwest side of Longde Pumping Station 11, and a 6-meter-wide temporary construction access road is also laid 2.5 meters away from the foundation pit.

[0049] The construction process of the diversion channel, the pumping station outlet channel 7, and the control intake channel 8, such as... Figure 2 As shown, based on the drawings and relevant hydrological and meteorological data, the flood control standard for Pump Station 11 and the channel dredging project is once every 10 years, the diversion flow rate is 24.6 m3 / s, the design adopts open channel diversion, the water passage cross section is trapezoidal, the design slope is 1:2.5, the design bottom width is 6.5m, the design elevation is 28.0m, and the design flood level is 30.5m.

[0050] The cross-section of the excavated diversion channel is trapezoidal, with a design flood level of 30.5m, an excavation bottom elevation of 28.0m, a bottom width of b = 6.5m, and a slope of m = 1:2.5. According to the hydraulic manual, the seepage prevention structure is made of cohesive soil and a mixture of clay and sand, which is flat, straight, and well-maintained, with a roughness coefficient n = 0.0225 and a slope bottom gradient i = 0.0012.

[0051] Water depth h = 30.5 - 28 = 2.5m

[0052] The water flow area A = (b + mh)h = (6.5 + 2.5 * 2.5) * 2.5 = 31.875㎡

[0053] The wetted perimeter X = b + 2h(1 + m²)¹ / ² = 6.5 + 2 * 2.5 * (1 + 2.5²)¹ / ² = 19.963 m

[0054] Hydraulic radius R = A / X = 31.875 / 19.963 = 1.597m

[0055] The discard factor C = (1 / n)R1 / 6 = (1 / 0.0225) * 1.5971 / 6 = 48.049 m1 / 2 / s

[0056] Flow rate Q = AC(Ri)¹ / ² = 31.875 * 48.049 * (1.597 * 0.0012)¹ / ² = 67.041 m³ / s

[0057] After verifying and calculating the flow rate of the designed trapezoidal open channel, the cross-sectional area is 31.875㎡ and the flow rate is Q=67.041m3 / s, which is greater than the design 10-year return period Q=24.6m3 / s, so the flow rate requirement is met.

[0058] Construction standards for the first cofferdam 1, the second cofferdam 2, the third cofferdam 3, the fourth cofferdam 4, and the fifth cofferdam 5.

[0059] The main material of the cofferdam is cohesive soil. Taking the fourth cofferdam (4) as an example, the crest width is 6.0m, the elevation is 32.5m, the channel bottom elevation is 23.0m, and the upstream and downstream slopes of the cofferdam are 1:5, meeting the design flood level of 30.4m (e.g., Figure 3 (As shown).

[0060] Backfill should be laid in regular layers from bottom to top, with each layer not exceeding 30mm in thickness. When using bulldozers for backfilling, a method of concentrated, single-pass transport can be adopted, with sections approximately 5-10m apart, using an advancing method to minimize soil loss during transport. When pushing earth to the backfilling area, the bulldozer should lift the blade once, unload the soil in piles, and move forward 0.5-1.0m, using the reverse motion to level the soil. Compaction should be performed using the bulldozer, with the tracks overlapping by half the width. A certain settling height should be reserved for the backfill to allow for gradual settlement and compaction under the influence of weight, alternating wet and dry conditions.

[0061] A 12t vibratory roller is used for compaction. Before compaction, a bulldozer is used for low-speed pre-compaction 4-5 times to make the surface flat. Then, a vibratory roller is used for static compaction, followed by vibration compaction. The driving speed should be controlled, generally 2 km / h. When using a road roller for compaction, a method of thin filling, slow driving, and multiple passes should be adopted. The overlap width of each roller should be about 15-25 cm. During operation, the roller should be more than 500 mm away from the edge of the fill to prevent slope slippage and collapse. Small tamping equipment should be used to compact areas where the slope corners cannot be compacted. A geomembrane is laid on the water-facing side of the weir. The geomembrane is double-sided hot-melt welded and laid flat. After laying, bags of sand are stacked to press down the edges to prevent leakage and erosion.

[0062] Multiple cofferdams were constructed in stages according to the requirements of the nodes and construction, and each stage worked simultaneously or separately to ensure that different sub-projects in the area were constructed in a synchronized manner according to the schedule, to ensure the schedule of the nodes, and thus to ensure the normal use of the original water supply lines such as the booster station.

[0063] Multiple cofferdams work in stages to ensure the drainage and flood control needs of upstream residents and farmland in the drainage direction, while also ensuring the continuous construction of buildings and structures at each stage of the construction period within the construction area.

[0064] The combined action of multiple cofferdams and diversion channels forms different drainage methods to cope with different levels of drainage and flood control requirements, including drainage methods during the non-flood season, drainage and flood control methods for floods that occur once every 10 years during the flood season, and drainage and flood control methods for floods that occur once every 20 years during the flood season.

[0065] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0066] In the several embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the division of units described above is merely a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. The aforementioned units may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention according to actual needs.

[0067] 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 them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for a water supply system based on flood control and water supply guarantee nodes, characterized in that: Includes the following steps: S1. Construct a first cofferdam (1) downstream of the water supply canal (13), construct a second cofferdam (2) upstream of the drainage canal (9), construct a seepage interception wall around the pump station (11), and construct a diversion channel to connect the water supply canal (13) and the drainage canal (9). S2. Construct the pump station outlet channel (7), the control inlet channel (8), the foundation pit of the pump station (11), and the foundation pit of the control gate (10). The outlet end of the pump station outlet channel (7) and the control inlet channel (8) are blocked from the drainage channel (9) by a second cofferdam (2). The inlet end of the control inlet channel (8) is connected to the intermediate channel (6). The intermediate channel (6) is blocked from the water supply channel (13) by a first cofferdam (1). S3. After the control water intake channel (8) is completed, a third cofferdam (3) is built at the inlet of the control water intake channel (8), and a fourth cofferdam (4) is built in the middle channel (6) to block the water inlet of the pump station (11) and the water inlet of the booster station (12). After the construction of S4, the third cofferdam (3) and the fourth cofferdam (4) is completed, the first cofferdam (1) will be demolished. After the construction of S5, pump station (11) and control gate (10) is completed, the second cofferdam (2), the third cofferdam (3) and the fourth cofferdam (4) are demolished.

2. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 1, characterized in that: In step S3, a fifth cofferdam (5) is constructed at the outlet of the pump station outlet channel (7), and the height of the fifth cofferdam (5) is higher than the height of the second cofferdam (2).

3. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 1, characterized in that: The foundation pit of the pump station (11) is surrounded by a continuous high-pressure jet grouting curtain, and the center line of the fourth cofferdam (4) coincides with the seepage cutoff wall.

4. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 1, characterized in that: Before constructing the first cofferdam (1), the second cofferdam (2), the third cofferdam (3), and the fourth cofferdam (4), geomembranes were laid on the bottom and slope protection.

5. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 1, characterized in that: The third cofferdam (3) and the fourth cofferdam (4) were filled with heavy silty clay excavated from the foundation pit of the control gate (10) and the foundation pit of the pump station (11), respectively. After the third cofferdam (3) and the fourth cofferdam (4) were filled, geotextile was laid on the water-facing side.

6. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 2, characterized in that: When the construction process was affected by a once-in-20-year flood disaster, the fifth cofferdam (5) was demolished so that the flood could be discharged directly through the foundation pit of the pumping station (11).

7. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 3, characterized in that: Before constructing the third cofferdam (3), the upper end of the high-pressure jet grouting cutoff wall was modified into an inverted trapezoidal section that was flush with the bottom and slope of the intermediate channel (6), and heavy silty clay was used for layered filling and compaction.

8. The construction method of a water supply system based on flood control and water supply guarantee nodes according to claim 1, characterized in that: The bottom elevation of the diversion channel is higher than the bottom elevation of the control inlet channel (8), and the bottom elevation of the control inlet channel (8) is higher than the bottom elevation of the pump station outlet channel (7).

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