Abstract:The sludge solidification soil in the dredging project is the high concentration non-Newtonian slurry.We carry out the fluidity test of sludge solidified soil and two-dimensional transient numerical simulation by the H-B rheological model,and determine the yield stress.We use the sludge solidified soils with water-solid ratios of 0.8,0.9 and 1.0,at 150,200,250 mm pipeline diameters,under the velocities of 1.5,2.5 and 3.5 m/s respectively,analyze the hydraulic transport characteristics,and fit the formula for calculating the hydraulic loss.The results show that the effects of flow velocity,viscosity and pipeline diameter on hydraulic loss are obvious.Hydraulic loss increases with the increase of flow velocity and viscosity,and decreases with the increase of pipeline diameter.

Abstract:In waterway dredging,port design and environmental protection dredging projects,high-precision bathymetric measurement results are often needed.The quality of bathymetric measurement directly affects the final measurement results,so the quality control of bathymetric measurement is particularly important.There’re two modes of bathymetric measurement,i.e.the traditional bathymetric measurement mode and RTK three-dimensional depth measurement mode,and the latter is a new technology popularized in the measurement specification of water transportation engineering.For RTK three-dimensional depth measurement,combining with the practical hydrographic engineering,we control the standardization,rationality and integrity of data from the software and hardware settings,field measurement process,data processing,and results quality inspection,to guarantee that the final result can meet the requirements.

Abstract:The Mirsarai coastal protection project of the Bangladesh uses 100 cm×80 cm×60 cm concrete blocks as the bottom protection structure.In the process of concrete block production and stacking,it is necessary to transport the block by the forklift. However,there are some difficulties in installation.Because the bottom block is not designed with a hook,it cannot be installed by crane. We can only use the long-arm excavator to install the hydraulic clamp for the clamp installation. However,the failure rate of the hydraulic clamp is high,and the block clamping is difficult.The strength is not well controlled when it is placed,and it is easy to cause collision damage between the blocks. So,we improve the existing machinery and equipment by making a self-locking clip according to the static friction self-locking phenomenon in physics.The clip clamps the block only by the frictional force generated by the clamp rubber composite structure and the gravity of the concrete block itself. When installing,it only needs to rotate the excavator bucket to change the force wire rope to loosen the block body,with no need of personnel assistance to effectively solve the problem of mechanical damage during the block installation.Moreover,since the self-locking clip is simple to manufacture and convenient to maintain,the production efficiency is improved and the cost is reduced.

Abstract:Solidified dredging silt is applied as a kind of filling resource,and pumping is the traditional conveyance method to transport it to construction site.We study the influence rule of calcium lignosulfonate plasticizer against the fluidity of solidified muddy soil by the experiment method,and analyze the experimental results.The results show that there exists a threshold value of calcium lignosulfonate dosage on the influence of solidified muddy soil fluidity,and the value is 0.8% in the condition of 5% cement content.When calcium lignosulfonate dosage is greater than the threshold value,the fluidity of solidified muddy soil presents stepped increase with the increasing of calcium lignosulfonate dosage.In actual engineering，there also exists a reasonable range of calcium lignosulfonate dosage,which is between 0.8% and 2.4% in the condition of 5% cement content.

Abstract:A project in Dalian intends to use dredged silt as filling resources after solidification treatment.It is necessary to obtain the optimum solidifying agent types and mix proportion to meet the strength requirements of engineering filling soil by means of experiments.There are too many factors affecting the strength of solidified soil,thus,the rough set theory is used to analyze the influences of water-solid ratio,curing agent dosage,curing agent type and external admixture on the strength so as to explore the most significant impact indicators.The results show that:1）In order to ensure that the strength of the solidified soil meets the requirements of the project fill soil,the research work should be carried out with the curing agent type and curing agent dosage as variables to explore the most economical curing agent preparation plan. 2）In practical application,no admixture can be added to save cost.3）In a certain range,the water-solid ratio can be properly increased to meet the transportation requirements.

Abstract:The original dredge pump impeller adopts cylindrical blades,which makes the flow passage smaller and the dredge pump efficiency lower.In view of the problem,we develop a three-bladed impeller with twisted blades without changing the outer dimensions of the impeller,test the hydraulic characteristics of the impellers of different number of blades under water and slurry conditions,analyze the water and slurry characteristics of the dredge pump,and compare the characteristics of the two different impellers.The results show that the newly developed twisted blade impeller increases by 40% of the maximum passing diameter,and the dredge pump efficiency increases by 10%.It can provide the references for the similar projects.

Abstract:The traditional steel sea anchor cannot provide enough traction force when large cutter suction dredger is excavating hard soil,so the excavating force of cutter cannot be exerted.We provide a variable load gravity box anchor to replace the traditional steel sea anchor,and analyze the strucure and characteristic of variable load gravity anchor by the example of the large cutter suction dredger “Tianjing”.The size of box anchor is based on the soil quality,sea condition and the pressure to ground.The amount of ballast iron can be changed according to the need.The pressure to the ground can be generated by the gravity of the anchor itself to provide enough grip force,and provide enough transverse pulling force for large cutter suction dredger.The productivity of large cutter suction dredger can be greatly improved.

Abstract:Crew should replace the worm-out cutter teeth in time to ensure the continuous construction of ships,and the replacement of cutter teeth mainly depends on manpower or special equipment.According to the construction characteristics of the cutter and combining with the related design drawings of the ship,we design the technical scheme of dismounting and hoisting device.By means of relevant calculation,we analyze and demonstrate the feasibility of this technical scheme.The lifting device is successfully applied to dredging construction site,which solves the problem of disassembly and installation of heavy cutter teeth that cannot be competent by manpower,and improves ship performance.It can provide references for the similar projects.

Abstract:In view of the large volume,large quantity of materials,high cost and difficult maintenance problems existing in the installation mode of the double flange differential pressure transmitter of cutter suction dredger,we probe into the installation mode and structural improvement of the double-flange differential pressure transmitter. By designing a reasonable sealing tank,we reduce greatly the sealing area and shorten the maintenance time;by designing the shock absorber and double welding connection mode,we prevent the part loose caused by vibration;by designing the a single flange instead of the double flanges,we simplify the transmitter structure and reduce the material consumption and the overall mass,and make the maintenance more convenient;in view of the long-term underwater work of the transmitter,we choose to use the anti-corrosion and rust-proof materials. By the comparative method for the transmitter before and after the improvement,we get to know the matter of attention and application effect of the transmitter after improvement.The real ship application effect proves that the improved transmitter is small in size and needs short maintenance time,which improves the ship’s efficiency.

Abstract:In the backfill engineering of the 3206 block of the third runway of Hong Kong international airport,the discharge performance of the cutter suction dredger’s diesel engine is substandard. Based on the analysis of the 16V240ZC diesel engine of cutter suction dredger “Tianbin”,we rematch the supercharger,renovate the the cooling water system,install the variable turbocharger geometry(VTG）electronic control system,and implement the real ship application.The results show that the air-fuel ratio of the improved diesel engine is optimized,the combustion efficiency is improved,the fuel consumption is reduced by 3%,the smoke value FSN decreases from 0.61 to 0.40,and the emission performance is improved.

Abstract:In view of the difficulty of the CSD in dredging and transferring construction of the clay-sand mixed soil,we choose the cutter’s type applicable to this kind of soil in Bayuquan area based on the analysis.The research result and practical application show that the ESCO-3G cutter is suitable for the clay-sand mixed soil,which can improve the construction efficiency of the CSD and cut down the construction cost,so as to improve the profit of the project.

Abstract:In order to satisfy the positioning accuracy of deep cement mixing vessel that is developed the first time in China,we propose a new automatic mooring positioning system with full consideration of operation conditions and working efficiency,and combine the fuzzy control thought and state machine to apply to the mooring positioning system.The fuzzy control can fuzzy on the current state of vessel.The state machine can divide the mooring positioning process into several states,different control parameters with different status to ensure fast and accurate positioning of vessel.The results show that the system satisfies the needs of the project,improves the construction efficiency and achieves good results.

Abstract:Aiming at the problem of shaft torque and power test of cutter suction dredger,field test and mud pump performance test are carried out,and a test device for shaft torque and shaft power test of cutter suction dredger is introduced.The performance parameters of mud pump at 850,900,950 and 1 000 r/min are obtained by using the method of measuring the power of ship strain gauge shaft,and the instantaneous and average pump shaft torque of diesel engine at 945 r/min and 18 throttle scale are calculated.It is concluded that:under the condition of constant flow rate,the higher the speed of pump is,the higher the lift and the higher the power is;when the flow rate is between 1 and 1.51 m3/s,the water powers of mud pump are very close at four rotational speeds；with the increase of flow rate,the higher the speed is,the higher the water power of pump is.

Abstract:According to the characteristics of cuttering clay,the section shape of cutterhead arm is optimized,the 3D model of cutterhead is established,and the stress and deformation of cutter at maximum power are analyzed.In order to meet the rigidity and strength requirements of the cutterhead,high strength and high toughness alloy steel material is adopted,and the manufacturing and welding process of cutterhead is optimized.The application of real ship shows that under the same working conditions,the power of the high-efficiency clay cutterhead is reduced by about 14.3% compared with the traditional clay cutterhead,which verifies the rationality and advancement of the high-efficiency clay cutterhead design.

Abstract:The laser scanning cabin technology is susceptible to various factors during using,such as ship movement,sandpile shape and ship shape,and the measurement data is inaccurate.Taking sand ship measuring volume in the Hongkong third runway 3206 section project as an example,we introduce the working principle,field operation method and data processing of three-dimensional laser scanner through actual construction on site,analyze its shortcomings,and improve the equipment,process and measurement scheme.The results show that the optimization scheme can improve the accuracy and efficiency of measurement data acquisition,which can provide references for the similar projects.

Abstract:Aiming at the problem that“Tianlin”cutter suction dredger constructions under medium-long period wave abroad,we establish the wind and wave computing model of“Tianlin”,and calculate the wave force acting on the hull under different wave heights,periods and directions.We obtain the load of wire rope of three-cable positioning according to the static equilibrium method,and determine the maximum wave height that cutter-suction dredger can construction according to the maximum load.The results show that with the increase of wave period,the wave force on the “Tianlin” gradually decreases in the range of medium-long period,the force on the wire rope of three-cable positioning also gradually decreases.When the wave period is between 13 s and 16 s,the maximum righteousness wave height that the “Tianlin” can construct is 0.55 m,and the maximum righteousness wave height that “Tianlin” can construct against the wave is 0.76 m.

Abstract:Taking the dredging and reclamation project in Kenya Ram Harbor as an example,and aiming at the problem that the distance between the onland sand source and sand filling bag construction area is too long,we study the construction technology of pipeline mortar transportation for sand bag filling,and propose creatively a safe and efficient method for the long-distance mortar transportation for the filling sand bag construction by optimizing the pump combination,rationally designing the long-distance mortar conveying pipeline and the combiner and the splitter suitable for the pipeline system,by which,we can reduce the input of equipment,cut down the construction cost,guarantee the construction progress,and achieve good economic and social benefits.At present,there is no mature construction technology of long-distance pipeline mortar transportation for sand bag filling in our country.The successful implementation of this technology has important referential significance for similar projects.

Abstract:With the gradual shrinkage of the domestic dredging market,dredging enterprises go abroad to undertake international projects.However,there is a big difference between the international engineering project management mode and domestic projects.How to reduce the cost and increase the efficiency,and control the benefit risk,is a matter to be thought about carefully by the dredging enterprises.Taking the Lamu Port project in Kenya as an example,we analyze the way of cost reduction and risk control,so as to provide reference for similar dredging projects.

Abstract:In the lake dredging,channel regulation,port construction and land reclamation engineering by the cutter suction dredger,problems such as huge pipeline resistance,severe abrasion and high energy consumption,etc.exist in the long-distance slurry transportation,which limit the productivity of dredgers.Based on the engineering practice,we study the technology of dredging pipeline’s air-injected transportation,analyze the influence of the air-injecting technology on the oil consumption and production efficiency of the dredger,and draw the conclusion that by applying the air-injecting technology,we can reduce energy consumption and increase the productivity of dredgers in the long-distance dredging.

Abstract:The improved Fujita pressure model is used to calculate the typhoon wind field No.8114,and the MIKE21 SW wave mathematical model is used to simulate the wave field under the typhoon.Through numerical model calculation,the wave situation of the wharf position in the transit of typhoon is provided,which provides the basis for engineering construction.The results show that during typhoon 8114,there was a Northwest gale with a magnitude of 12 or more in the engineering sea area;the effective wave height of Dengbu Island dock was about 2.5 m,and that of Xishan Island dock was about 2.0 m;the wave period was about 4.5 s;the wave directions of Dengbu Island dock and Xishan Island dock were in W—NW direction.From the simulation results of the wave field in the dock waters during the typhoon crossing,it can be seen that the outer sea waves have no obvious impact on the project waters,and the project waters are still affected by local wind and waves in the island.

Abstract:In the port construction project,the interference caused by the construction while navigating is always a big problem for the construction unit and the port management unit.In the course of construction of hydraulic structures,due to the large number of ships and frequent transport of ships to and from the construction area,an enormous pressure is brought to the safety of the normal port operation.Based on the construction of the southeast breakwater project in Jingtang Port Area of Tangshan,we set up a dispatch centre to manage the construction vessels coordinately and plan rationally the entry and exit routes of the construction vessels,optimize the organization and dispatch mechanism,so as to maximize the constriction efficiency and reduce the influence of the merchant ships on the construction under the prerequisite of not exerting too much pressure on the port operation.

Abstract:The steel pile positioning grab boat,because of its positioning characteristics,such as small occupancy of construction waters,small impact of avoidance and high positioning accuracy,is widely applicable to the construction of the excavation narrow waters and the operation channel widening section.Especially in narrow areas, its positioning advantage is significantly better than that of the traditional anchor cable positioning grab ship.It is difficult to control the construction accuracy of grab dredger.Combined with engineering examples,the problems of ultra-depth,construction safety and construction quality in construction are solved,and the results are satisfactory and can be used as a reference for dredging projects with similar working conditions.

Abstract:Aiming at the problems of poor geological conditions,tight construction period and budgetary constraints of temporary wharf area,we analysis and research the temporary wharfs with different structural forms in Penang Drainage Filling STP2 Project,Malaysia.Then we select one of the temporary steel sheet pile wharf structures,which adapts to harsh geological conditions,is simple and fast in construction,and has low cost.The design achieves good construction effect,meets the needs of the project,and has certain popularization significance.

Abstract:Due to the advantages of low cost,simple operation,convenient layout and stable performance,the pressure tide gauge has obvious advantages in depth measurement.Based on the actual situation of the project of the re-survey of crude oil wharf and navigable waters of China-Myanmar crude oil pipeline,the main factors affecting the data error of pressure tide gauge are analyzed in three aspects:atmospheric pressure,water density and zero drift.The following conclusions are drawn:synchronous observation of atmospheric pressure changes can eliminate or reduce the impact of atmospheric pressure changes;reducing the depth of the tide gauge and calculating the tidal data by using the bottom seawater density can significantly reduce the influence of the change of seawater density;by comparing the atmospheric pressure values observed synchronously by several tide gauges in the air at the same time,the correction value of zero drift can be determined.Combining with the actual situation of the project,the elevation transfer of synchronous tide gauge method is briefly introduced.

Abstract:In order to meet the requirement of high-precision measurement of complex river terrain,the Sirius PRO UAV aerial survey system was taken as the research object,and the field survey and accuracy comparison of Fenhe River Basin were carried out.Under the condition of Non-GCPs,a series of data products,such as DOM,DEM and DLG,with a scale of 1:1000 in the measuring area,were produced.The final results were analyzed and the accuracy was compared.The results show that:1:1000 large-scale mapping accuracy meet the requirements of specifications；the efficiency is significantly improved,while other additional digital products can be provided；the results can provide rich and accurate data support for the follow-up design and construction.

Abstract:There is no clear conversion relationship between the shear strength of vane test and the bearing capacity of the foundation in the current national standards and relevant detection standards of water transport engineering,which leads to the inconsistency of the evaluation criteria of the bearing capacity of the foundation by vane test.This paper compares the conversion formulas for estimating the bearing capacity of foundation by shear strength of vane test in the codes of geotechnical investigation,highway and railway foundation design.Taking an example of soft foundation reinforcement and testing project,this paper estimates and verifies the bearing capacity by various formulas.The results show that the simplified formula deduced in accordance with Code for Design of Building Foundation is more suitable for evaluating the reinforcement effect of soft foundation treatment,and can be used as the basis for checking the bearing capacity of soft foundation reinforcement by vane test.

Abstract:In order to solve the problems of inaccurate calculation results and great influence of human factors when applying layered summation method to settlement calculation of dredger fill preloaded foundation,the characteristics of resilience of dredger fill are studied,and an modified layered summation method for settlement calculation of dredger fill is put forward.The modified layered summation method is applied to the settlement calculation of the preloaded foundation of a dredger fill project,and compared with the layered summation method and the actual monitoring settlement.The results show that,without amending the calculation results,the calculated results of modified layered summation method are closer to the actual settlement monitoring results,with an error of about 3%.The accuracy of settlement calculation of preloaded foundation of dredger fill is improved.The modified layered summation method provides guidance for the subsequent backfill estimation and site utilization,and provides reference for similar projects.

Abstract:For the construction of sand bag cofferdam on the super soft foundation at sea,the cofferdam is prone to uneven settlement and unstable foundation due to the deep silt and poor bearing capacity of the foundation.At present,the state has strict approval for the sea use,and the construction process is strictly prohibited to use the red line beyond sea use.So,it is impossible to dissipate the load by using traditional technology to increase the bottom bearing sand bag or front riprap and fill of cofferdam.Through the stress analysis of the formation process of sand-bag cofferdam and based on the typical section test,we adopt integral long sand-bag embankment to deal with the uneven settlement of sand-bag cofferdam,which ensures the uniform stress in the process of the sand-bag levee construction,reduces uneven settlement,and speeds up the construction.

Abstract:Based on the measured surface settlement data of the vacuum preloading project in Tianjin Lingang Economic Zone,the consolidation degree of the foundation was predicted by hyperbolic method,three-point method,Asaoka method and pore pressure method.The results show that the hyperbolic method has smaller prediction results and greater artificial influence,which affects the economic performance of the project;the three-point method has a larger prediction result and cannot guarantee the quality of the project;based on the settlement calculation theory of under-consolidated soil,it is considered that the calculation results of the pore pressure consolidation method can be used as the lower limit value of the prediction results,while the Asaoka method is in good agreement with the measured results.It is suggested to change the single evaluation method of hyperbolic method in similar projects.The three prediction methods are mainly used for comparative analysis,and the pore pressure consolidation degree is supplemented by comprehensive evaluation.

Abstract:As a new building material,geosynthetic plays an increasingly important role in engineering construction.Aiming at the anti-seepage and anti-filtration effects of this type of material in the land reclamation project,we analyze the physical and hydraulic characteristics of the material,and introduce the role and function of the material in different construction environment combining with the cofferdam and enclosure engineers of the dredger filling project.The results show that geosynthetic can play a very excellent role of anti-seepage and filtration in dredger filling project.The shortcomings of geosynthetic should be avoided or properly protected in order to maximize its main function.

Abstract:In view of the problems of quality such as floating,turning,folding and low construction efficiency in the laying of three-way geotechnical mats in deep water unsheltered area,we carry out on-site investigation and statistics to identify the causes and formulate relevant countermeasures.The test section was completed by matching the length of geotextile and distance of vessel movement,introducing professional geotextile-laying ship and encrypting ballast point.The results show that the grading pass rate can reach 96.7%,the axis deviation pass rate can reach 95.7%,the construction efficiency is increased by 33.3%,and the construction period and economic benefits are remarkable.

Abstract:During the straight-line vacuum preloading construction of Binzhou Port,we monitor the surface settlement,groundwater level and pore water pressure.By the indoor geotechnical test before and after the vacuum preloading construction,we analyze the physical and mechanical indices of soil layers and the change of vane strength,and evaluate the soft base reinforcement effect.The results show that the correlation between water level decline and surface subsidence is very high during vacuum preloading.The dissipation value of pore pressure increases and decreases in the short time after the drainage plate is set.For the silty clay and clay layer with weak permeability,the change of vacuum under the membrane in a short time has little effect on pore pressure.