Large caisson automatic drip water maintenance system

Abstract

This invention provides an automatic drip-water curing system for large caissons, comprising the following: constructing several water supply points and vertical main pipes; pre-installed water pumps at the water supply points, with the pump outputs connected to the vertical main pipes; constructing a ring-shaped pipeline around the already poured caisson section, the ring-shaped pipeline being divided into an outer ring and an inner ring, and connecting to multiple vertical main pipes; installing pressure control valves on the pipelines connecting the ring-shaped pipeline and the vertical main pipes; and providing drip holes on the ring-shaped pipeline; and constructing corresponding ring-shaped pipelines as the caisson is poured layer by layer. This invention has the advantages of good curing effect and low cost.

Description

Technical Field

[0001] This invention relates to the field of caisson maintenance technology, and in particular to an automatic drip water maintenance system for large caissons. Background Technology

[0002] As the core load-bearing component of gravity-type wharves, the quality of early concrete curing of precast caissons directly determines the long-term durability and operational safety and stability of the structure. A berth expansion project in a certain seaport adopted a gravity caisson structure. The main dimensions of the caisson are length × width × height = 24.5m × 15.8m × 21.0m (including a 1m front toe width), and it consists of 3 × 5 independent compartments. Each caisson weighs approximately 3525t and is precast to high standards using C40 reinforced concrete. Due to the caisson's large size, complex structure, and the use of a layered casting construction process, extremely high requirements were placed on the timeliness, uniformity, and continuity of concrete curing. Traditional curing methods were no longer suitable for the actual needs of the project. The expansion project of the container terminal in the western port area of ​​a certain district has caissons with dimensions of 26m in length, 16.5m in width, and 23m in height, with a single piece weighing 3800t. Both are prefabricated using C40 chloride-resistant concrete. Both projects face the common technical challenges of prefabricated and maintained large caissons.

[0003] Through research and analysis of the application of traditional maintenance methods in similar engineering sites, the following four main problems were found: First, the curing coverage is incomplete. During the layered pouring process, the top surface and side walls of the poured layers are prone to curing delays, and the complex structure of the multi-compartment caisson inside the caisson easily creates curing blind spots. For example, in the No. 18 berth project of Haicang Port Area of ​​a certain port, traditional manual curing can only cover the outer wall of the caisson and some surface compartments, while the curing coverage rate of the side walls of the deep compartments inside is less than 60%, resulting in problems such as peeling and micro-cracks on the concrete surface in this area. Secondly, water resources are wasted significantly. Manual watering and spraying methods are greatly affected by external wind speed. In windy coastal areas, the amount of water lost increases significantly as the height of the caissons increases. Data from the expansion project of a container terminal in the western port area of ​​a certain port shows that during traditional spraying maintenance, the water loss rate exceeds 55% when the caisson height exceeds 15m, which not only reduces the maintenance effect but also causes a large waste of precious water resources. Third, it has poor environmental adaptability. Coastal areas have strong sunlight and low air humidity, resulting in rapid water evaporation. Traditional curing methods are unable to maintain a continuously moist curing state on the concrete surface. Actual measurement data from a bay port project in summer showed that only 30 minutes after manual watering, the surface moisture content of the concrete dropped to below 60% of the curing requirement, which is not conducive to the development of concrete strength and the improvement of crack resistance. Fourth, the cost-effectiveness is poor. Manual maintenance requires dedicated personnel for continuous operation, resulting in high labor costs. Fixed sprinkler systems are not only complex to install, but also difficult to reuse. The manual maintenance cost for a single caisson in the No. 18 berth project of a certain port in Haicang Port reached 6,800 yuan, and the fixed sprinkler system in the Shenzhen Port project cost over 80,000 yuan per set. Moreover, it cannot be reused in subsequent projects, resulting in a low overall cost-effectiveness ratio for maintenance and failing to meet the economic requirements of the project. Summary of the Invention

[0004] To address the aforementioned problems, this invention discloses an automatic drip-water maintenance system for large caissons, comprising the following: Construct several water supply points and a vertical main pipe. Water pumps are pre-installed at each water supply point, and the pump outputs are connected to the vertical main pipe. Each water supply point consists of a polyethylene plastic water tank with a minimum capacity of 3m³. 3 At least four water supply points are set up, located at the four corners of the caisson, and water pumps operate to pump water into the vertical main pipe. In addition, the vertical main pipe is continuously spliced ​​in the vertical direction as the caisson is poured.

[0005] A ring-shaped pipeline is constructed around the already poured caisson section. The ring-shaped pipeline is divided into an outer ring and an inner ring, and it connects to multiple vertical main pipes. The outer ring is used for the maintenance of the outer sidewalls of the caisson, while the inner ring is used for the maintenance of the inner sidewalls of the caisson.

[0006] Pressure control valves are installed on the connecting pipes between the ring pipeline and the vertical main pipe. These pressure control valves can be understood as pressure monitoring throttle valves with electrical control, eliminating the need for manual adjustment. They can be composed of a shut-off valve and a pressure sensor. By monitoring the water pressure at the input and output ends of the throttle valve, the opening and closing size of the throttle valve can be adjusted, enabling automated control and precise maintenance of the caisson.

[0007] Drip holes are provided on the ring-shaped pipe. Water is sprayed from the drip holes onto the caisson for moist curing.

[0008] As the caisson is poured layer by layer, corresponding ring pipelines are constructed. This ensures that the poured sections are cured after each pour, and that the pressure control valves are configured to not affect the water supply between layers.

[0009] Preferably, the annular pipe has a specification of DN20, the drip hole diameter is 2mm, the hole spacing is controlled between 5cm and 10cm, and the drilling direction is inclined downward at 8° to 12°. This hole arrangement meets the maintenance needs.

[0010] Preferably, quick-connect couplings are pre-installed on the annular pipe and the vertical main pipe, and the ends of the connecting pipes are compatible with the quick-connect couplings. This facilitates rapid connection setup, and the detachable structure also allows for reuse. Furthermore, the connecting pipes are preferably flexible hoses, offering greater connection flexibility.

[0011] Preferably, several one-way valves are evenly spaced along the outer loop, and the one-way valves all point in the same direction. This one-way valve configuration allows for zoned operation of the outer loop, ensuring that water flows in only one direction. For example, with four one-way valves, the outer loop is divided into four zones (A, B, C, D), and the water flows in the direction of A→B→C→D→A, forming a cycle. Each zone is connected to a water supply point. If the caisson section being maintained in zone B requires a larger water volume due to factors such as temperature and wind, the water supply to the point connected to zone B will increase. However, due to the one-way valves, water cannot flow to zone A. Simultaneously, the large water flow from the drip holes in zone B results in relatively less water flowing to zone C, minimizing interference with zone C. Therefore, this configuration allows for precise control of the water supply to a specific zone, enabling precise maintenance operations. Similarly, reducing water demand follows the same principle.

[0012] Preferably, the pump has the following specifications: power 1.1kW, head ≥30m, and outlet pressure adjustable range of 0.2MPa-0.4MPa. This meets the needs of maintenance operations.

[0013] Preferably, it also includes a control system to start and stop the water pump and adjust the pressure control valve, thereby achieving automated operation. This system controls whether the water pump is working and the output water pressure, as well as adjusts the pressure control valve. If the water pressure feedback from the pressure control valve is too low, the water pump's supply pressure is increased.

[0014] Preferably, the control system includes a near-field temperature and humidity sensor and a far-field temperature and humidity sensor. The near-field temperature and humidity sensor is used to measure the temperature and humidity near the caisson, and the far-field temperature and humidity sensor is used to measure the temperature and humidity at a distance of 500m-1000m from the caisson. The evaporation rate of water is determined by the feedback from both sensors, thereby controlling the water supply rate for maintenance.

[0015] Preferably, the control system includes an anemometer. The anemometer is used to determine the extent to which the caisson is affected by wind in a certain direction, and thus adjust the water supply speed in that wind direction.

[0016] The beneficial effects of this invention are as follows: 1. The method of building and maintaining the structure layer by layer has advantages such as saving water resources and reducing labor costs compared to manual water spraying.

[0017] 2. The ring pipeline is equipped with a check valve and a pressure control valve. The arrangement of multiple water supply points ensures that the ring pipeline in each area of ​​each floor can be used for precise control while meeting water demand, so as to achieve the effect of precise maintenance.

[0018] 3. Equipped with a control system, and with the help of relevant sensors such as temperature and humidity sensors, wind speed and direction instruments, and pressure control valves, it can realize automated and precise maintenance operations, freeing up manpower and improving maintenance results.

[0019] 4. The structure involved in this invention can be reused, thereby reducing the overall cost of the entire project. Attached Figure Description

[0020] Figure 1 These are comparison images of the crack effects of the caisson in this invention; Figure 2 This is a graph showing the change in maintenance intensity over time according to the present invention. Detailed Implementation

[0021] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0022] 1. This embodiment provides an automatic drip water maintenance system for large caissons, which consists of four parts: 1.1 Distributed water storage and booster unit (power core) This unit, serving as the power core of the entire maintenance system, primarily provides a stable water source and pressure guarantee. A four-point distributed layout ensures the uniformity and stability of the water supply. Regarding the water storage tank configuration, a 3m³ polyethylene plastic water storage tank is placed at each of the four corners of the caisson. This type of tank offers advantages such as corrosion resistance, light weight, and good sealing, ensuring a continuous supply of water for maintenance and effectively improving the stability of the pipeline water pressure, preventing insufficient water volume or pressure fluctuations from affecting the maintenance effect. For the booster pump selection, each water storage tank is equipped with a small self-priming booster pump with technical parameters set as follows: power 1.1kW, head ≥30m, and adjustable outlet pressure range of 0.2MPa-0.4MPa. The four independent power cores can flexibly adjust the water pressure according to the maintenance needs of different areas, ensuring that the maintenance effect of each part meets the expected standards. If the wind is strong, the booster pump head can be adjusted to ≥35m and the upper limit of the outlet pressure can be increased to 0.5MPa according to the actual situation on site, to ensure that the drip hole can still maintain stable water output in strong wind environment; at the same time, in view of the large number of caisson compartments, branch pipeline control valves are added to each water storage tank to achieve precise water supply control for different compartment areas.

[0023] 1.2 Vertical water supply system (transmission channel) The vertical water supply system is a crucial transport channel connecting the water storage and pressurization unit with the interlayer drip irrigation device. Its core design feature is the ability to extend synchronously with the height of the caisson, adapting to the layered pouring process of the caisson. For pipe selection, DN25 PVC-U pipes are used as the main vertical water supply pipe. This type of pipe offers multiple advantages, including corrosion resistance, lightweight, easy connection, and low cost, meeting the requirements of marine environments while reducing construction and installation difficulties. For fixing, pipes are reliably fixed to the outer concrete wall of the caisson using pipe clamps, or installed using pre-embedded parts at the four corners of the caisson, ensuring a stable pipe structure and preventing displacement or damage due to wind, vibration, or other factors during use. For extension, as the caisson pouring layers rise, the pipes are extended section by section using threaded connections. This connection method features good sealing and easy disassembly, enabling the curing range to increase synchronously with the caisson height, ensuring timely and effective curing of each pouring layer. In one project, the caisson was 21m high, and the vertical water supply system was built by splicing 10 sections of pipe, with no leakage throughout the process. 1.3 Interlayer Circular Drip System (Actuator Terminal) As the end point that directly acts on the concrete surface, the core design of the interlayer ring drip system is to achieve uniform drip curing and ensure that a continuous and stable water film is formed on the concrete surface. In terms of pipeline layout, after each layer of concrete is poured and before the formwork is removed, a ring of DN20 PE flexible hoses or steel pipes is installed on the outer side of the top of the caisson partition wall as a ring drip pipe. The pipes encircle the caisson to form a closed drip ring, ensuring that the curing area can fully cover the entire concrete sidewall. In terms of drip hole design, laser precision drilling technology is adopted, with the hole diameter strictly set at 2mm and the hole spacing controlled between 5cm and 10cm. The drilling direction is slightly inclined downward at 10°. This design ensures that water droplets fall vertically onto the concrete sidewall surface and flow naturally along the sidewall to form a uniform water film, effectively eliminating curing dead corners. In terms of control valve settings, each water storage tank is equipped with an independent control switch, which can adjust or shut off the water supply of the corresponding area individually. This includes pressure control valves and check valves, which can flexibly adapt to the curing needs of different compartments, improve the targeting and flexibility of curing operations, and facilitate maintenance in local areas without affecting the operation of the overall curing system.

[0024] 1.4 Intelligent Control System (Control Center) As the central control unit of the entire curing system, the intelligent control system's core function is to automate and program the curing process, reduce human intervention, and improve the stability and reliability of curing quality. In terms of control core selection, a multi-loop time controller is used to uniformly manage the power supply of four booster pumps, ensuring the coordinated and orderly operation of each power unit. Regarding operating mode settings, the system can flexibly set curing cycles based on ambient temperature, wind speed, curing stage, and concrete technical requirements, using near-field temperature and humidity sensors, far-field temperature and humidity sensors, and anemometers. For example, an intermittent curing mode of "50 minutes on, 10 minutes off" can be adopted. This mode ensures continuous moisture on the concrete surface while optimizing water resource allocation and avoiding waste. In terms of adaptability, the controller parameters can be adjusted in real time according to changes in weather conditions, effectively responding to changes in curing needs under different weather conditions, ensuring that the curing effect is not significantly affected by external environmental factors, and further improving the system's environmental adaptability. During the high-temperature period in summer, the Beibu Gulf Port project adjusted the curing cycle to "open for 40 minutes and close for 20 minutes" to avoid excessive evaporation of moisture and prevent water accumulation on the concrete surface.

[0025] 2. Evaluation of Experimental Results To scientifically and objectively evaluate the application effectiveness of this automatic dripping maintenance system, a comparative experiment was conducted using two methods: automatic dripping maintenance and traditional manual maintenance. The experiment involved 14 days of follow-up monitoring and data collection, and a comprehensive evaluation was carried out from multiple dimensions, including quality effect and economic benefits.

[0026] 2.1 Comparative Analysis of Appearance Quality This assessment focuses on the effectiveness of concrete crack control. On the 3rd, 7th and 14th days after the caisson is demolded (critical curing period), a full survey was conducted on the vertical walls and interlayer joints of the caisson using automatic drip curing and traditional manual curing, respectively. The results of the comprehensive observation of the three items were then used.

[0027] like Figure 1As shown in the observation results, it is clear that during the 14-day critical curing period of the project, no visible cracks wider than 0.02 mm were found on any concrete surface of the caissons using the automatic drip curing system. This result fully demonstrates that the curing system can create a continuously stable moist environment for the concrete, effectively ensuring the normal development of concrete strength and successfully inhibiting the generation of early plastic shrinkage and drying shrinkage cracks, with extremely significant crack control effects. In contrast, the caissons cured by traditional manual methods began to show fine cracks from the 3rd day, and the number and cumulative length of cracks increased continuously over time. By the end of the 14-day curing period, the caissons cured by manual methods had an average of 9.3 cracks and an average cumulative crack length of 5.6 meters, while the crack data for the automatic drip curing system remained zero. This stark quantitative comparison powerfully proves that the automatic drip curing system is significantly superior to traditional manual curing in controlling concrete cracks and improving appearance quality.

[0028] 2.2 Strength of test blocks under the same conditions The concrete strength grade of the two precast caissons on site is C40P8. Two different curing methods were adopted at the pouring site, but three sets of concrete test blocks were taken under the same curing conditions. Their 3d, 7d and 28d compressive strengths were tested according to the specifications.

[0029] like Figure 2 As shown in the test results, the concrete test blocks cured by automatic dripping in the project exhibited higher strength at all ages than those cured by traditional manual watering. Specifically, the strengths at 3 days, 7 days, and 28 days in the Beibu Gulf Port project were 5.3 MPa, 2.3 MPa, and 3.5 MPa higher, respectively; and the strengths at all ages met the design and specification requirements. Furthermore, the standard deviation of the 28-day strength of the automatically drip-cured test blocks was below 1.0, significantly lower than the 1.15-1.23 of traditional manual curing. This data indicates that automatic dripping curing not only effectively promotes concrete strength growth but also ensures high uniformity and stability of concrete quality, avoiding excessive strength dispersion caused by uneven curing, thus providing strong protection for the safety and reliability of the caisson structure.

[0030] 3. Economic Benefit Analysis 3.1 Direct Cost Comparison In terms of labor costs, traditional maintenance requires two workers to work in three shifts without interruption, with a maintenance cycle of 14 days. The labor cost is calculated according to the local standards for each project, at 200 yuan / person / day in Beibu Gulf Port, and the total labor cost is 2 people × 14 days × 200 yuan / day = 5600 yuan. In contrast, automatic drip water maintenance only requires one inspector, who spends 3 hours a day checking the equipment and replenishing water. The total labor cost is 0.125 man-days / day × 3 × 14 days × 200 yuan / man-day = 1050 yuan. The labor cost savings per caisson reach 81.25%, and the labor cost savings effect is extremely significant. In terms of water consumption, the traditional maintenance method uses about 15m³ of water per day, with a total water consumption of 210m³ over 14 days. The water fee is calculated at 3.5 yuan / m³ according to the project standard for Beibu Gulf Port, with a total water cost of 735 yuan. The automatic drip water maintenance system replenishes about 5m³ of fresh water per day, with a total water consumption of 70m³ over 14 days and a total water cost of 245 yuan. The water conservation effect is outstanding and in line with the concept of green construction.

[0031] 3.2 Overall Economic Benefits In terms of initial investment amortization, the total cost of this automatic drip irrigation maintenance system (including 4 water pumps, pipes, controllers, and other complete equipment) is approximately 5,000 yuan. Assuming it can be reused 50 times, the amortized equipment cost per caisson is 100 yuan. Comparing the overall total cost, the traditional maintenance cost (labor + water fees) is 6,335 yuan, while the automatic drip irrigation maintenance cost (labor + water fees + equipment amortization) is 1,395 yuan. Therefore, the overall maintenance cost per caisson using automatic drip irrigation is reduced by 4,940 yuan. Considering the equipment's reuse in subsequent projects, the long-term economic benefits are considerable. Furthermore, the project saves an additional 5,000 yuan per caisson due to reduced crack repair costs, further highlighting the system's economic value.

[0032] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A large-scale caisson automatic drip water maintenance system, characterized in that, Includes the following: Construct several water supply points and vertical main pipes, with water pumps pre-installed at the water supply points, and the output end of the water pumps connected to the vertical main pipes; A ring-shaped pipeline is constructed around the already poured caisson section. The ring-shaped pipeline is divided into an outer ring and an inner ring, and it is connected to multiple vertical main pipes. A pressure control valve is installed on the connecting pipe between the ring pipeline and the vertical main pipe; Drip holes are provided in the ring-shaped pipe; As the caissons were poured layer by layer, corresponding ring-shaped pipelines were constructed.

2. The automatic drip water maintenance system for large caissons according to claim 1, characterized in that: The specifications of the annular pipeline are DN20, the diameter of the drip hole is 2mm, the hole spacing is controlled between 5cm and 10cm, and the drilling direction is inclined downward at 8°-12°.

3. The automatic drip water maintenance system for large caissons according to claim 1, characterized in that: The annular pipe and the vertical main pipe are equipped with quick connectors, and the ends of the connecting pipes are compatible with the quick connectors.

4. The automatic drip water maintenance system for large caissons according to claim 1, characterized in that: Several one-way valves are evenly spaced along the outer loop, and the one-way valves all point in the same direction.

5. The automatic drip water maintenance system for large caissons according to claim 1, characterized in that: The pump has the following specifications: power 1.1kW, head ≥30m, and outlet pressure adjustable range of 0.2MPa-0.4MPa.

6. The automatic drip-water maintenance system for large caissons according to any one of claims 1 to 5, characterized in that, It also includes a control system to start and stop the water pump and adjust the pressure control valve to achieve automated operation.

7. The automatic drip water maintenance system for large caissons according to claim 6, characterized in that, The control system includes near-field temperature and humidity sensors and far-field temperature and humidity sensors.

8. The automatic drip water maintenance system for large caissons according to claim 6, characterized in that: The control system includes an anemometer and wind direction sensor.

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