1.Introduction

As a kind of dredger equipment widely used in dredging projects, the construction process of the cutter suction dredger plays an important role in port channel construction, river dredging and coastal engineering. The cutter suction dredger can efficiently carry out underwater excavation operations and transport the excavated materials to the designated location through its unique excavation and conveying system. This article will deeply explore the construction process of the cutter suction dredger, including equipment composition, construction process, key technical points and practical application cases.

2.Equipment composition and functional characteristics

(I) Main equipment of the cutter suction dredger

The cutter suction dredger is mainly composed of the following key parts:

  1. Excavation equipment: including the cutter suction arm, the cutter head and the drive device. The cutter suction arm is used to support and position the cutter head, the cutter head is responsible for cutting and loosening the underwater soil, and the drive device provides power to the cutter head to ensure that it can effectively carry out excavation operations.
  2. Conveying system: mainly composed of mud pumps and pipelines. The mud pump is responsible for extracting the excavated mud from the suction head and transporting it to the mud unloading area through a pipeline. The design of the conveying system needs to consider factors such as the concentration of the mud, the conveying distance, and the wear of the pipeline.
  3. Propulsion and positioning system: including the main propeller, side thrusters and positioning pile device of the hull. The main propeller is used for the navigation and displacement of the dredger, and the side thrusters help the dredger to turn and position in narrow waters. The positioning pile device can stabilize the hull during the construction process to ensure the accuracy of the excavation operation.
  4. Control system: Modern cutter suction dredgers are equipped with advanced control systems for monitoring and adjusting the operating parameters of various equipment, such as auger speed, mud pump flow, dredger position, etc. Through automated control, construction efficiency can be improved and construction quality can be guaranteed.

 

(II) Functional characteristics

  1. Efficient excavation capability: The cutter head of the cutter suction dredger can adapt to different types of soil, such as sand, clay, silt, etc. Its cutting and loosening action makes the excavation process efficient and continuous.
  2. Advantages of long-distance transportation: With powerful mud pumps and suitable pipeline systems, the cutter suction dredger can transport mud to the mud unloading area several kilometers or even tens of kilometers away, meeting the needs of long-distance dredging projects.
  3. Good maneuverability and adaptability: The dredger can navigate and operate in various water environments, including ports, rivers, coastal areas and other areas. Its positioning system ensures stable construction under complex hydrological conditions.
  4. High degree of automation and intelligence: Advanced control systems can realize automatic adjustment and fault diagnosis of equipment, reduce manual intervention, and improve the safety and reliability of construction.

3.Detailed explanation of construction process

(I) Preparation before construction

  1. Engineering survey and design: Before construction, it is necessary to conduct a detailed survey of the geological conditions, hydrological conditions, and obstacle distribution of the construction area. According to the survey results, a reasonable construction design plan is formulated, including excavation depth, width, mud transportation route, and selection of mud unloading area.
  2. Dredger commissioning and inspection: Comprehensive commissioning and inspection of the cutter suction dredger to ensure the normal operation of each equipment. In particular, check the wear of the excavation equipment, the sealing of the mud pump and the integrity of the pipeline, as well as the accuracy of the control system.
  3. Material and personnel preparation: Prepare the materials required for construction, such as fuel, lubricants, and wearing parts. At the same time, organize a professional construction team, including crew members, operators, maintenance personnel, and technicians, and clarify the responsibilities and tasks of each person.

(II) Positioning and anchoring

  1. Dredger positioning: According to the construction design requirements, the cutter suction dredger is sailed to the designated construction location. During the voyage, the navigation equipment and positioning system of the dredger are used to ensure that the dredger arrives at the predetermined location accurately.
  2. Positioning pile placement: After arriving at the location, the positioning pile device is lowered to stabilize the dredger at the construction location. The angle and depth of the positioning pile need to be adjusted according to the water depth and geological conditions to ensure the stability of the dredger during the construction process.
  3. Equipment adjustment and calibration: After the dredger is fixed, the excavation equipment and conveying system are finally adjusted and calibrated. Ensure that the cutting depth of the auger head is appropriate, the suction and discharge pipes of the mud pump are unobstructed, and the operating parameters of the entire equipment system meet the construction requirements.

(III) Excavation and transportation operations

  1. Start the equipment: Start the various equipment of the cutter suction dredger in sequence according to the operating procedures, including the auger drive device, mud pump and related auxiliary equipment. During the startup process, closely observe the operating status of the equipment to ensure that no abnormal situation occurs.
  2. Excavation operation: The auger head starts to rotate and lowers to the excavation position to cut and loosen the underwater soil. The suction arm is adjusted according to the construction requirements to ensure the uniformity and continuity of the excavation. During the excavation process, the operator needs to adjust the auger speed and cutting depth in time according to the type and hardness of the soil to achieve the best excavation effect.
  3. Mud transportation: The mud pump extracts the excavated mud from the suction head and transports it to the mud unloading area through the transportation pipeline. During the transportation process, it is necessary to monitor the parameters such as the concentration, flow rate and pipeline pressure of the mud to ensure the stable operation of the transportation system. According to the actual situation, the speed of the mud pump can be adjusted to adapt to different conveying distances and mud characteristics.
  4. Real-time monitoring and adjustment: Use the control system and monitoring equipment on the dredger to monitor key parameters such as excavation depth, mud flow, equipment power, etc. in real time. According to the monitoring data, the operator can adjust the operating parameters of the equipment in time, such as auger speed, mud pump flow, dredger posture, etc., to ensure construction quality and efficiency. At the same time, monitor the wear of the pipeline to detect and deal with possible blockages or leakage problems in time.

(IV) Quality control during construction

  1. Excavation accuracy control: Through the precise operation of the positioning system and suction equipment, the excavation depth and flatness are controlled to ensure that the design requirements are met. During the construction process, water depth measurement and terrain scanning are carried out regularly, and the design drawings are compared to timely discover and correct excavation deviations.
  2. Mud concentration control: Reasonable control of mud concentration is the key to ensuring transportation efficiency and reducing pipeline wear. According to soil characteristics and construction requirements, the mud concentration is controlled within a suitable range by adjusting the excavation parameters and mud pump flow. In general, the mud concentration can be controlled by measuring the density or solid content of the mud.
  3. Mud unloading area management: In the mud unloading area, the mud is discharged and treated reasonably. According to the characteristics of the mud and environmental requirements, natural sedimentation, mechanical dehydration and other methods can be selected for mud treatment to reduce the impact on the environment. At the same time, monitoring points are set up in the mud unloading area to monitor the sedimentation of the mud and changes in water quality to ensure compliance with relevant environmental protection standards.

(V) Finishing work

  1. Equipment cleaning and maintenance: After completing the excavation and transportation operations, the cutter suction dredger is thoroughly cleaned and maintained. Timely clean the residual mud in the cutter head, mud pump and transportation pipeline to prevent solidification and blockage. Inspect and repair the equipment, replace severely worn parts, and prepare for the next construction.
  2. Construction records and summary: Organize various records during the construction process, including construction parameters, equipment operation status, quality inspection data, etc. Make a comprehensive summary of this construction, analyze the existing problems and deficiencies, and put forward improvement measures and suggestions to provide experience reference for similar projects in the future.
  3. Environmental protection and restoration: After the construction is completed, the construction area is restored. Clean up the waste and temporary facilities generated during the construction process and restore the cleanliness of the water environment. According to needs, take appropriate ecological restoration measures, such as planting aquatic plants, releasing fish fry, etc., to promote the recovery of the ecosystem.

4. Analysis of key technical points

(I) Selection and application of auger heads

  1. Characteristics of different types of auger heads: There are many types of auger heads for cutter suction dredgers, such as straight blade, curved blade, toothed blade, etc. Each type is suitable for different soil conditions. Straight blade auger heads are suitable for digging soft soils such as sand and soft clay, with high cutting efficiency and simple structure; curved blade auger heads perform well in digging harder clay and rocks, and their curved blades can generate greater shear force; toothed blade auger heads are suitable for digging soils containing more hard particles, such as pebbles, coral reefs, etc., and their toothed blades can effectively crush hard materials.
  2. Basis for auger head selection: In actual construction, it is crucial to select the appropriate auger head type based on geological survey results and soil characteristics. For sandy soil, a straight blade auger head should be selected, and the auger speed should be appropriately increased to improve excavation efficiency; for clay layers, if the soil hardness is moderate, a curved blade auger head can be selected, and the cutting depth and auger speed should be adjusted according to the viscosity of the soil; when encountering complex geology containing pebbles or rocks, a toothed blade auger head is the best choice, and it is necessary to reduce the excavation speed and increase the cutting force to break hard materials.
  3. Wear and maintenance of auger head: During the construction process, the auger head will be worn by soil particles, especially when excavating soil containing abrasive materials, the wear is more serious. Regularly checking the wear of the auger head and promptly repairing or replacing the severely worn blades is the key to ensuring excavation efficiency. At the same time, reasonably adjusting the excavation parameters and avoiding unnecessary high-load operation can extend the service life of the auger head.

(II) Mud conveying technology

  1. Conveying distance and pipeline selection: The slurry conveying distance is an important factor affecting the design of the conveying system. After determining the conveying distance, it is necessary to select a conveying pipeline with a suitable diameter and material. Generally speaking, a longer conveying distance requires a larger pipe diameter to reduce pipe resistance, but it is also necessary to consider factors such as the weight, cost, and difficulty of laying the pipe. For long-distance transportation, highly wear-resistant rubber pipes or wear-resistant alloy pipes can be used, and the smooth transportation of mud can be ensured by increasing the power of the mud pump or setting up a relay pump station.
  2. Mud concentration control technology: Too high mud concentration will lead to increased pipe wear and increased transportation resistance, while too low concentration will reduce transportation efficiency. Therefore, it is crucial to adopt effective mud concentration control technology. During the excavation process, the mud concentration can be adjusted in real time by adjusting parameters such as excavation speed, mud pump flow, and cutting depth of the auger head. In addition, the mud concentration can be monitored in real time using equipment such as mud concentration sensors, and the monitoring data can be fed back to the control system to achieve automated concentration control.
  3. Pipeline wear and maintenance: The solid particles in the mud have a strong wear effect on the conveying pipeline, especially in the elbows, valves and other parts of the pipeline, where the wear is more serious. In order to reduce pipeline wear, the following measures can be taken: use wear-resistant lining materials such as ceramics, wear-resistant rubber, etc. on the inner wall of the pipeline; optimize the pipeline layout, reduce the number of unnecessary elbows and valves, and reduce the flow rate changes of mud in the pipeline; regularly inspect and maintain the pipeline, and replace severely worn pipe sections in time.

(III) Positioning and navigation technology

  1. Positioning system accuracy requirements: In the construction of cutter suction dredgers, positioning accuracy directly affects the quality and efficiency of excavation operations. A high-precision positioning system can ensure the stable construction of dredgers under complex hydrological conditions and ensure the accuracy of excavation positions. Generally speaking, the positioning accuracy should meet the requirements of the construction design. For projects with high precision requirements, such as fine dredging of port channels, the positioning accuracy should reach the centimeter level.
  2. Combination of satellite positioning and sonar positioning: At present, the commonly used positioning technologies for cutter suction dredgers include satellite positioning (such as GPS, Beidou, etc.) and sonar positioning. The satellite positioning system can provide positioning information worldwide, but there may be problems such as signal blocking or interference in some waters. Sonar positioning determines the position of the dredger by measuring the propagation time of sound waves in water. It has high accuracy and stability in underwater positioning. Combining satellite positioning with sonar positioning technology can achieve complementary advantages and improve the reliability and accuracy of the positioning system.
  3. Real-time positioning data feedback and dredger attitude adjustment: During the construction process, the positioning system obtains the position data of the dredger in real time and feeds it back to the dredger’s control system. According to the positioning data, the control system automatically adjusts the dredger’s attitude and position to ensure that the cutter suction equipment works at the correct excavation position. At the same time, by real-time monitoring of the dredger’s attitude changes (such as heel, pitch, heave, etc.), the force of the positioning pile device and the dredger’s propulsion force are adjusted in time to ensure the stability of the dredger and the construction quality.

5.Practical application cases

(I) Taizhou Hongjiachangpu drainage and storage project

Taizhou Hongjiachangpu drainage and storage project is an important water conservancy project in Taizhou. The total length of the river channel is 18.2km, the river width is 100~182m, the riverbed elevation is -1.0~-2.0m, the project level is III, and the flood control and drainage specification is once in 20 years. The soil is mainly clay and silt mixed with silt, and the soil is 1~4 types of soil. The total amount of earth excavation is about 1.47x106m3, and the dredging is to the abandoned material site about 10km away. Limited by the geographical location of the project and combined with the actual situation of the construction site of this project, the river channel earthwork mainly adopts OCSD400 suction dredger (spacing 3000m, flow 2500m3/h, power 1103kW) for earthwork dredging and excavation, equipped with 2 booster pump dredgers (mud pump flow 2500m3/h, power 810kW) for relay transportation.

  1. Project background and challenges: Taizhou City is located in the coastal area, and the Hongjiachangpu River is an important flood discharge and drainage channel in the area. Due to long-term siltation, the flood discharge capacity of the river has gradually weakened, affecting the flood control safety and ecological environment of the surrounding areas. In order to improve the flood discharge and drainage capacity of the river and improve the regional water environment, the Taizhou Municipal Government launched the Hongjiachangpu Drainage and Storage Project. The implementation of this project faces many challenges, such as the long length of the river, large width changes, and complex soil, which places high requirements on the construction process and technology of the cutter suction dredger.
  2. Construction plan formulation and technological innovation:
  • Segmented operation and flow construction: According to the changes in the length and width of the river, the entire river regulation project is divided into multiple construction sections, and each construction section is equipped with a corresponding cutter suction dredger and booster pump dredger to implement segmented operation and flow construction. By reasonably arranging the construction sequence and operation time, the construction efficiency is improved and the idle time of equipment is reduced.
  • Real-time monitoring and dynamic adjustment: During the construction process, advanced measurement technology and monitoring equipment are used to monitor the excavation depth of the river channel, mud flow, equipment operation status, etc. in real time. According to the monitoring data, the excavation parameters and mud delivery flow are adjusted in time to ensure the quality and efficiency of the construction. At the same time, the position and posture of the dredger are dynamically adjusted to ensure the accuracy and stability of the excavation operation.
  • Environmental protection measures and mud treatment: During the dredging process, effective environmental protection measures are taken to reduce the impact on the surrounding environment. During the mud transportation process, multi-stage sedimentation tanks and filtration devices are set up to separate the mud into solids and liquids and purify the water quality. The treated clean water is discharged back to the river channel, and the mud cake is transported to a special treatment site for harmless treatment and resource utilization, achieving zero discharge and resource utilization of the mud.
  1. Construction process and results: During the construction process, the cutter suction dredger and the booster pump dredger cooperated closely and efficiently completed the dredging task of the river channel according to the predetermined construction plan and process flow. After several months of intense construction, a total of about 1.47x106m3 of earthwork was excavated, and the flood discharge capacity of the river channel has been significantly improved, reaching the flood control standard of once in 20 years. At the same time, the water quality of the dredged river channel has been significantly improved, and the surrounding ecological environment has been effectively restored.
  2. Project benefits and impacts: The successful implementation of the Taizhou Hongjiachangpu drainage and storage project has not only improved the flood control and drainage capacity of the region, protected the lives and property of the people, but also improved the ecological environment of the river channel and enhanced the overall image of the city. The implementation of this project has provided valuable experience and demonstration for similar urban river channel regulation projects, and promoted the widespread application of the construction technology of the cutter suction dredger in water conservancy projects.

6.Conclusion and Prospect

As an efficient dredging equipment, the cutter suction dredger plays an irreplaceable role in modern water conservancy projects, port and waterway construction, and environmental remediation. Its construction technology covers many aspects such as equipment composition, construction process, key technical points, and quality control. By rationally selecting equipment, optimizing construction processes, applying advanced technology and strict quality control measures, the efficiency and environmental protection of cutter suction dredger construction can be guaranteed.

In future dredging projects, with the continuous advancement of technology and the increasing environmental protection requirements, cutter suction dredgers will face new opportunities and challenges. On the one hand, large-scale, intelligent and automated cutter suction dredgers will become a development trend to meet the needs of larger and more complex projects. On the other hand, green dredging technology will be more widely used, such as environmentally friendly treatment of mud, efficient use of energy, and protection of the ecological environment. At the same time, with the integration of emerging technologies such as artificial intelligence, big data and the Internet of Things, the construction process of cutter suction dredgers will be more refined and efficient, providing stronger support for global water conservancy project construction and marine resource development.

In practical applications, the construction process of cutter suction dredgers needs to be continuously optimized and innovated according to specific engineering projects. Only by constantly summarizing experience and lessons, strengthening technology research and development and management innovation, improving construction quality and efficiency, and reducing costs and environmental impacts can the sustainable development of the cutter suction dredger industry be promoted.

 

Sally Peng

Tel /WhatsApp /Wechat :+86 18554212226 

Email: oceanpump2@tsbeng.com, sales@sanddredgers.com