Abstract:Due to the advantages of easy operation,high detection accuracy and economical advantages,the sub-bottom profiler has obvious advantages in the accurate detection of underwater pipelines.Based on the actual situation of the dredging project of the Shenzhen Tonggu channel,this paper uses the sub-bottom profiler to accurately detect the deep buried pipeline under the channel,and further explores the application range and application key technology of the sub-bottom profiler.The main conclusions obtained are as follows：the differences in wave impedance between the original soil layer and the riprap,the riprap and the pipeline near the submarine pipeline are large,and the clear detection image information can be obtained.The method of dragging the side of the middle of the ship and shortening the streamer is adopted to avoid the large swing of the towed fish and improve the plane detection accuracy.Keeping the attitude of the underwater fish catching stable,and using the filtering method to deal with the invalid waves generated by the ship noise and water flow,waves,etc.,this paper provides a basis for the future development of the submarine pipeline protection construction plan.

Abstract:Aiming at the matters related to barge stability,taking reclamation for Seri Tanjung Pinang phase II development(STP2)as an example，we introduce the method of construction for riprap work in shallow water area with limits of specific conditions,and adopt barge stability calculation as theoretical basis to determine heeling angle of barge,which is successfully verified by STP2 project.It provides a relatively simple and practical basis for barge safety checking for similar projects.

Abstract:As a very important part of the construction process,the dredging project cost directly affects the quality of the project.In recent years,as the dredging project moves towards inland lakes and rivers,the requirements for environmental protection dredging gradually increase.The project cost also needs to change according to the local conditions to avoid the calculation error,which is very beneficial to improve the economic benefit of the project.Taking the inner lake environmental protection dredging project as an example,according to the relevant design scheme and the specific construction conditions of the construction area,we put forward the problems that should be avoided,modify the dredging quota and formulates the project cost,and strive to reduce the error and improve the accuracy of project cost.

Abstract:In view of the problem of temperature crack in large volume cast-in-situ concrete wave screen wall,the causes of crack are analyzed from three aspects of concrete hydration heat,external temperature and binding force.In terms of design,reasonable segmentation of wave retaining wall and optimization of mix proportion are carried out,and the temperature differences when the cracks occur are calculated.In terms of construct,the temperature of raw materials is controlled,the temperature of concrete is monitored in real time,and the screw hole sleeve is transformed into cooling pipe.Thus,the cracks of large-volume cast-in-place concrete are controlled.

Abstract:In order to compare the similarities and differences between the analysis method of the Geoslope software and the codes,we calculate and analyze a simple homogeneous soil slope,derive the calculation formula adopted by the process data of the software through Geoslope,and compare it with the code method.The results show that the Geoslope software calculates the resistance force smaller than the code method,so the safety factor calculation result is larger than the coeds.When using the software to calculate the stability of the slope,the safety factor should have a certain margin value compared with the standard limit.

Abstract:The split hopper barge is one of the key facilities that assists large dredger dredging construction.In view of the domestic research for the 4 000 m3 large-scale self-propelled bow-connection split hopper barge,this paper analyzes the functional characteristics of the barge,i.e.opening the left and right half bodies for quick mud unloading,being capable of unloading mud in shallow water area,realizing overflow of different cabin loading heights through an overflow units,carrying out the shore blowing operation by the bow blowing device,etc.,the paper proposes the key technology of this type of ship design,and solves a series of technical problems such as the ship’s splitting status stability,splitting hydraulic cylinder,as well as mud tank sealing,etc.,and grasps the core technology of the large self-propelled bow-connection split hopper barge,so as to provide reference for the design of the same kind of ship.

Abstract:During the construction of the cutter suction dredger,the effect of the cutter load on the construction is extraordinarily significant.As the process of the cutter acting on the rock and soil is 3D,and the deficiency of traditional 2D cutting theory in the load analysis of the cutter,the three dimensional cutting theory applicable to the cutter is made.Based on the 2D cutting theory,the 3D mechanical model of rock and soil for the analysis of the cutter load is proposed,and the 3D coordinate matrix of all the teeth of the cutter is established.Using coordinate transformation method to judge the cutting forces,the expression of the cross load,ground load and thrust load of the cutter are given.The example shows that the proposed method can be used to calculate the crosswise load,the ground load and the thrust load of the cutter.As the design of the cutter and the safety construction of the cutter suction dredger,the theory will play a guiding role.

Abstract:The checking works of dredging monitoring systems of trailing suction hopper dredgers and cutter suction dredgers are closely related to the construction production.To improve the accuracy and rationality of the checking work of dredging monitoring system for dredger,the principle and calibration method of partial no trace ability construction equipment for trailing suction hopper dredgers and cutter suction dredgers are analyzed,such as the principles and checking methods for the cutter depth,for the lowering depth of drag arm.The main construction equipments of the dredgers are also analyzesd,such as the principle and calibration method of densimeter and flowmeter.The working experience from practice is combined to verify the feasibility of the adjusted method after the verification of key construction equipment,along with the reliability of verifying results.The methods for improving the quality and efficiency of the calibration work of the two types of dredgers are obtained.By improving the quality and efficiency of the checking work,construction accuracy and production efficiency are improved,and the dredging project can be completed more quickly and more smoothly.

Abstract:We deeply study the automatic mooring positioning control system for sanding vessel used in the construction of three runways of Hong Kong Airport,and develop a new automatic mooring positioning control system according to its construction method,which has 50 cm dynamic positioning accuracy.Then we analyze the control model,point out the difficulties of the system,and apply the fuzzy state machine control method to overcome difficulties.The distance deviation between the center point and the start point,the distance deviation between the control point and the working line,and the angle deviation between the center line and the working line are fuzzed by the fuzzy state machine control method.The ship state is based on the position deviation and the angle deviation comprehensive results,and different control parameters are adopted in different states.According to the actual application effect of the sanding vessel,it is confirmed that the control system has higher precision and response speed.

Abstract:Taking the reclamation and filling project of T7，T8，T9 area in Tianjin Port-vicinity Economic Zone as an example,we analyze the characteristics of bank slope and the structure of soil layer in the construction area.By optimizing the traditional construction technology,we realize the efficient excavation construction of the bank slope by construction ships.Through the detailed introduction of the construction process,we provide a solution for the excavation of super long underwater bank slope under complicated geological conditions.We also summarize the construction experience to further optimize the construction technology for the cutter suction dredger.

Abstract:A numerical model which contains wave,tidal flow and sediment is established and the model is verified by wave,tidal current,sediment and siltation changes of topography,to solve the problem of the depth reserved for sedimentation under synchronous construction of breakwater and waterway at a port area of Dongying port.On the basis of the mathematical model,the construction process is decomposed into several nodes for modeling and calculation,and the statistics of different time stages from the end of construction to completion acceptance are combined.We gain the rule of waterway siltation during the period of synchronous construction and prediction the depth reserved for sedimentation.The above studied achievements can not only provide a technical support for the waterway channel project,but also offer positive basis for reference for similar study.

Abstract:In modern dredging construction,it is often necessary to transport the silt of rivers and lakes over a long distance.For the problem of long distance transportation in dredging,a series of construction technologies for dredgers and booster pumps are studied.The results show that booster pumps in series can significantly increase the transport distance of sediment.The theoretical value of pipeline resistance loss helps to determine the location of booster pump-ships,and in the process of construction,the construction cooperation between dredgers and pump ships is particularly important.Through the Taihu dredging project,we conclude the technological process,pipeline transport resistance and location distance in series of pump ships.Therefore,the efficiency of construction and construction quality are improved.

Abstract:In view of the problems of poor soil conditions and high flatness requirements in the dredger filling engineering,the flatness control was studied.Through the on-site measurement of elevation and the review of the slope ratio of the dredger filling area，and the calculation method of earthwork balance,the spacing of the trunk line layout and the layout of the pipeline interface were determined.After the completion of the project,it is shown that in the medium coarse sand dredger filling engineering，the method of arranging branch pipe spacing of 40 m and controlling the elevation and progress according to the bottom elevation，can effectively shorten the mechanical leveling time of the dredger filling area and save the cost about 473,000 yuan.

Abstract:During the construction of the LYG-302-H1.1 section of the phase Ⅱdredging projcet of the 300,000 tons waterway in Lianyungang Port,pipe clogging frequently occurs in cutter-suction dredgers,which seriously affects the construction efficiency.To avoid the frequent occurrence of this accident,we analyze the characteristics of soil layers and the reasons of pipe clogging by collating the soil data in the accident prone area,and summarize the soil quality index of such difficult excavation areas.The results show that the soil layer in this kind of area is not uniformly distributed.The clay layer contains clayey silt and sandy silt at the same elevation,and exists some calcareous cementation in the clay layer.The number of standard penetration is greater than 20.

Abstract:If the dredger fill is sandy and the fill area is silt layer,it is difficult to solve the damage problem of silt caused by the dredger fill in the filling process by traditional blow-filling construction,which will cause a large amount of silt concentration therefore great difficulty in subsequent foundation treatment construction.If the silt layer in the fill area is too thick and the fill construction speed is too fast,the conventional fill construction may also cause the landfill to be unstable.Combined with the Panama Colon Container Port(PCCP)project,the slope stability theory is used to explore the application of stratified block filling in ultra-thick silt bottoming area .The construction process of a block layer fill is for reference of related projects.

Abstract:The hydraulic transport of coarse and gravel sand has its characteristics and the adaptability of the existing hydraulic calculation model for calculating the hydraulic loss and criticality of this type of soil needs further inspection.In response to the problem of large transmission resistance and high risk of pipe blocking in the Malaysian Johor Bahru Garden Filling Project of China,we carry out the hydraulic transport characteristic test using the newly built large-scale and two-phase flow transport test platform,and test the hydraulic loss in the case of different flow rates and concentration,and the movement pattern of sand in the pipeline is observed by means of high-speed photography.Through the statistics and fitting analysis of the test data,the characteristics of hydraulic transport resistance,critical flow velocity and average slip rate are studied.A hydraulic resistance and critical flow velocity calculation model for the soil is proposed,and the model is used in actual engineering projects.

Abstract:For the problem that the clay balls formed by dredgers during the construction of certain clay formations are likely to cause blockage of transportation pipeline,we study mechanism of clay pilling.By means of the indoor crash tests and restoring forming conditions,we propose two hypotheses that the clay and sand are bonded into the ball and the block clay is worn into the ball.By studying the characteristics of on-site construction conditions，geological conditions and characteristics of clay balls when clay balls are formed to block the pump，it is found that the hypothesis of wearing into the ball from block clay is more in line with the actual situation on site.In order to reduce the probability of clay balls blockage，we propose a series of construction measures to avoid the blocking of clay balls.

Abstract:Nowadays,cast-in-place mass concrete，as a major constitute of large-scale structures，has been widely used due to its advantages in integrity，endurance，high strength and execution convenience.However，since mass concrete performs poorly in hydration heat dissipation，it may get involved in quality issues，such as cracking，which impact the structure endurance and security.Taking the construction of large volume concrete for the cast-in-place pier of no.301 oil and liquid chemicals berthing project in Panjin Port as an example，the anti-cracking property of large volume concrete is calculated，and the construction quality is improved through the calculation.

Abstract:Through different construction stages and different load forms，the stress calculation of the main beam，secondary beam and bracket of overwater construction platform of the high-pile wharf are carried out.The strength，stiffness and safety performance of the platform meet the specifications and application requirements，and the safety and stability of the platform are guaranteed.The setting up of the steel platform ensures the smooth construction of rock socketed pile and its upper structure.

Abstract:In the design of high-pile wharf，selection and arrangement of pile foundation impact on structure scheme significantly.For the structural design of high-piled beam-slab wharf in a project，we analyze the influence factors，such as hydrogeological conditions，designing load，etc.On the premise of security and reliability of the structure，we propose a recommended structure scheme by comparing two different selections and arrangements of pile foundation，and empirically summarize the construction points of recommended structure scheme according to the actual situation.

Abstract:The impact of the breakwater and waterway engineering on the tidal current field of the engineering sea area and the sudden siltation of the navigation channel under the conditions of heavy wind and waves are the key problems in the construction of Guangli Port area of Dongying Port.According to the collected data and hydrology survey data of project site，we studied the hydrodynamic condition，sediment environment，process of beach evolution.A numerical model which contains modules of tide and sediment was established，which was used to simulate the influence of engineering construction on the tidal field and to calculate the distribution rule of sudden siltation under heavy wind and wave conditions.The results showed that the Guangli Port area of Dongying Port has the characteristics of irregular half-day tidal current with reciprocating flow.The engineering construction has the biggest influence on the tidal field in the entrance.Taking spring tide as an example，the biggest increase of maximum flood and ebb are 0.32 m/s and 0.16 m/s.At the 10 year return period storm conditions，the thickness of siltation around the entrance is more than 0.5 m，the maximum is 1.02 m.

Abstract:According to the influence of the main scale of the sand barrier embankment on the wave elements (wave height，period，etc.) in the harbor area，the numerical simulation method of the MIKE21 is used to study the stability of the harbor under the cover of the gradient submerged levee，and design wave elements for each calculation point under wave conditions of different return period are obtained.The results show that when the wave direction is close to the course of the channel，the wave is greatly affected by the channel refraction，and the wave height is significantly reduced in the channel，while the wave height is increased on both sides.When the angle between the wave direction and the channel is about 20°，the water depth difference between the channel and the slope increases，and the wave energy refracted to the slope of the channel is enhanced.When the angle between the wave and the channel is about 42°，the influence of the channel on the wave energy propagation is not obvious.The design of the high water level is 2 years.Under the action of waves，the conditions of port stability in the port are relatively poor，and the current plan cannot meet the requirements of the specification.

Abstract:The complex topography，water depth and velocity conditions in the construction area of the lower reaches of the Yangtze River are very unfavorable for the formation of the riprap dam.Relying on the section II of the direct waterway regulation project of the 12.5 meters deep waterway below Nanjing of the Yangtze River，the impact of external conditions on the drop point is reduced by modifying the riprap equipment and adding tumbling barrel constraint construction to reduce the riprap height and the riprap drift so as to achieve the purpose of controlling the stone falling point and achieve the precise positioning of underwater riprap.The engineering application effect is good，and the cost is reduced while the construction quality is improved，which provides a reference for the following similar projects.

Abstract:Aiming at the difficulties encountered in the driving of the AZ profile steel sheet piles，taking the sheet pile works in an artificial island project as an example，we carry out the selection of equipment，the force analysis at the pile tip and the design of the pile cap replacement structure，and apply the construction technology of the combination of vibration hammer and impact hammer.The combination solves the dilemma of lack of insufficient penetration force when the driving depth exceeds over 20 m using only the vibration hammer and the dilemma of the pile head easily being damaged using just the impact hammer.Therefore，such combination has favorable construction effect and promotion significance.

Abstract:As a new type of sheet pile structure，steel pipe pile/AZ steel sheet pile composite wall has the advantages of simple structure，large bending stiffness，small deformation,economy and broad application prospect. It has never been applied in large-scale deep water docks in domestic engineering instance，therefore the characteristics of the structure remain to be further investigated.According to a wharf project，we explore the mechanical properties of this type of composite wall by using the vertical elastic foundation beam theory，also the influence of pile-soil interaction is considered.The result shows that pipe/AZ combined steel sheet pile has greater bending stiffness than the traditional structure，and it has good economy due to the reasonable stress distribution of horizontal soil arch structure.Combined wall displacement deformation is small，then horizontal displacement meets the use requirements.

Abstract:The main influencing factors of suspended sediment concentration are hydrodynamic conditions.Studying the impact of hydrodynamic forces on aquatic plants in Taihu Lake is conducive to improve the water ecology of Taihu Lake by improving hydrodynamic conditions.We apply 3D water dynamic and ecological numerical simulation software to setup lake current model and wave model of Taihu Lake，verify the model results，and use verified current and wave model results as input parameters of suspended sediment model to calculate the change of scouring and silting and the concentration of suspended matter in Taihu Lake at different current and wave conditions.The results show that driving force of hydrodynamic is wind，the larger wind speed causes the larger current speed and wave height in the lake，and the concentration of suspended sediment caused by current and wave becomes larger.The mathematical model can well simulate the relationship among current，wave and suspended sediment concentration of Taihu Lake.

Abstract:To deal with the difficulty of sand resource reuse and ecological landscape problem caused by sand siltation in the multi-sand river，taking the Gasitai River’s treatment as an example，we analyze the laws of sand-water process and riverbed evolution.Blocking up the coarse sand to reuse and discharging fine sand to improve sedimentation morphology in the flood period，and filling the mid-lower channel with clean water in the non-flood period by the terraced dropping and landscape dam，we can raise the survival rate of plants and improve the construction of downstream water ecosystem，meanwhile provid reference for subsequent projects.

Abstract:To solve the problem of suspension diffusion in dredging engineering，a cutter suction experiment device is designed.The best operation parameters are determined by the orthogonal experiment.PSF and CPAM were added in the process of strangulation，and the anti-diffusivity of the overlying water was studied by changing the turbidity and the diffusive height of the sediment.The result shows that the reamer rotating speed is the key factor to the cutter-suction experiment.In the process of cutter suction，PSF and CPAM can reduce the turbidity of overlying water，control effectively the diffusion height of sediment and improve the water quality of overlying water.The performance of PSF was better than CPAM in controlling turbidity，which could be suppressed below 40 NTU in the case of adding PSF as optimum dosage.Adding PSF and CPAM can effectively inhibit the diffusion of suspended solids and avoid the secondary pollution to the surrounding environment.

Abstract:Limited by the project cost，working environment，working time and social resource allocation，inland river surveying and mapping is mostly conducted by traditional surveying and mapping methods.For long surveying line，complex and comprehensive control surveying technology，large water level ratio，scattered operating points，etc.，the methods research of overlong inland river control survey and depth survey is necessary.The network CORS is used for the control survey，which can get accurate coordinates and be used directly for the base station to launch.The RTK three-dimensional water depth measurement can effectively eliminate the influence of moving draught and wave and avoid water level correction error caused by tidal level observation.After comparing with the traditional surveying method，the accuracy meets the standard requirement and the method is proved accurate and reliable.The research can improve efficiency and save cost，and provide reference for the smooth implementation of similar river channel measurement.

Abstract:In the light of reasonable disposal and resource utilization of dredged polluted sediment，we point out the shortages in dredged sediment utilization，and introduce three resource utilization methods，i.e.，backfill soil，baking-free building material，and planting soil，on the basis of which，reasonable selection of resource utilization methods is analyzed quantitatively by discriminating the content of organic matter，heavy metal，salinity and lithologic character of dredged polluted sediment.Furthermore，the effectiveness of quantitative selection method is verified by enumerating two cases，i.e.baking-free brick production and planting soil production using Taihu and Baiyangdian sediment，respectively.The research result reveals that it is accessible to determine the resource utilization method of environmentally friendly dredging soil from the view of lithology，organic content，salt content.

Abstract:In the coast recovery and renovating project of Haizhou Bay Rizhao Port North District port shoreline，it is proposed to use the dredging engineering ship to form a golden coast，with a beach area of 449，700 m2.Considering that during the dredging construction，pollutants contained in the sea sand will spread in the seawater and thus will pollute the marine environment，we predict the diffusion of pollutants during the filling process.Adopting the computational fluid dynamics (CFD) method，we carry out the numerical simulation on the trend of pollutant diffusion in the coastal dredging construction，analyze the diffusion of pollutants，and evaluate the risk of marine environmental pollution by the construction scheme.According to the trend of pollutant diffusion and analysis results，we propose suggestions for anti-fouling screen layout scheme.Practice proves that the anti-fouling screen can prevent the spread of pollutants when applying to the dredger filling engineering.