Abstract:Compared with other ship lifts，the Three Gorges ship lift has the characteristic that the upstream water level varies greatly. At the same time，it is also affected by the ship lock filling. Through 13 voyages of 4 ships with different ship types，scales and displacement，the influence of the upstream water level change on the process of ship lift docking at the upstream water level of 145 m of the Three Gorges ship lift is obtained，the main content is fluctuation and variation characteristics of water surface in ship chamber. It provides an important basis for formulating the technical requirements of the three Gorges ship lift.When the upstream water level is between 145 and 150 m，affected by the water filling of the double-line ship lock，the upstream approach channel water level changes significantly aggravate the influence on the upstream docking of ship chamber，and easily leads to insufficient depth of ship chamber，affecting the safety of ship lifts and ships.

Abstract:The large miter gate of ship lock is characterized by large plane scale，high water retaining head and large submergence depth. Its performance and operation safety are closely related to the hydrodynamic characteristics. The hydrodynamic characteristics of large miter gate are studied comprehensively through mathematical model and physical model. Based on the analysis of the influence of gate library boundary conditions on the peak value of hydrodynamic resisting torque of miter gate，we put forward the scientific and reasonable shape of large miter gate library，and determine the gap at the bottom of the gate，the depth of the gate library and the connection mode between the gate library and the upstream and downstream side walls. Based on the physical model of 1:20 miter gate，we study the characteristics of opening and closing force and hydrodynamic resisting torque of miter gate under uniform and variable speed operation，analyze the change rules of miter gate position and angular velocity under different opening and closing modes，and propose the variable speed operation mode of miter gate of Datengxia shiplock. The experimental results show that the variable speed operation mode can significantly reduce the maximum opening and closing force of the miter gate and reduce the difficulty of the operating machinery design. By studying the characteristic indices of the inertia water head and reverse surge under different operation conditions of lock and hydro-junction and the characteristics of miter gate drift under the action of the reverse surge，we put forward comprehensive measures to deal with the drift of large miter gate.

Abstract:There will be complex reciprocating flow in the middle channel of the dispersed cascade ship lock during the filling and discharging operation. In addition to the influence of the operation mode of the ship lock，the length，width，initial water depth and roughness of the channel will also have an important impact on navigable flow conditions. Taking the layout plan of the middle channel of the two-level double line lock as an example，the hydrodynamic characteristics，especially the influence law of the key parameters，are simulated by establishing a series of mathematical models. The results show that：1）The fluctuation characteristics in the middle channel vary greatly in different lock operation modes. 2）The increase of the width and initial water depth of the middle channel can significantly improve the flow fluctuation characteristics and can be used to improve the navigation flow conditions of the middle channel. 3）The increase of the channel length cannot effectively improve the flow conditions. 4）The roughness has no obvious effect on the improvement of various hydraulic indexes in the channel，but with the increase of the channel roughness，the overall water surface gradient in the channel decreases.

Abstract:The river regime and topographic conditions of Xiangjiaba Hydropower Station downstream are complex，and the fluctuation at the entrance of the approach channel downstream of the ship lift is larger during the flood discharge. Prototype observations show that a wavy water jump is formed in the stilling basin when the surface hole is discharged，and it is transmitted downstream in the form of short waves. Affected by a variety of complex conditions，the longitudinal high-frequency fluctuations of the river under the dam transform into lateral oscillation waves near the entrance area of the approach channel downstream of the ship lift，which has a significant impact on the safety of ship navigation. Analyzing the prototype observation results of the hydraulic fluctuation characteristics of the approach channel entrance area of the downstream approach channel of the Xiangjiaba Junction under different flood discharge flows，we know that the surface flood discharge is the main factor leading to short-wave oscillations in the approach channel entrance area，and its discharge is linearly related to the fluctuation of the entrance area. Moreover，the power station discharge and the middle hole flood discharge have a positive effect on reducing the hydraulic fluctuation in the entrance area.

Abstract:Hydraulic ship lift is a new type navigable building for the high dam，which has no operation experience for reference at home and abroad. To ensure the safe and reliable operation of the hydraulic ship lift and solve the fuzzy problem of risk assessment of important risk sources，we establish the risk factors failure tree of the hydraulic ship lift to identify the operation risk factors and their logical relationship，and propose a risk analysis method based on fuzzy theory for the important risk sources. Taking Jinghong hydraulic ship lift as a research example，we quantitatively analyze the risk level of risk factors，and carry out the risk assessment for the important risk sources of hydraulic system and mechanical system. The results show that this method can objectively evaluate the risk and provide technical reference for risk warning and management of hydraulic ship lift.

Abstract:Beach restoration projects often use vegetation to increase the shore stability. In order to study the influence of rigid vegetation on hydrodynamics and morphology，the cylinder is used instead of rigid vegetation to carry out a numerical simulation study of vegetation-flow-sediment under different vegetation densities，and the relationship of vegetation density with the velocity and bed shear stress is analyzed. The results shows that ：1）The numerical simulation flow velocity is consistent with experimental data. 2）With the increase of vegetation density，the velocity and bed shear stress increase first and then decrease.3）The bed morphology change law shows that the overall formation of sand ridge is not so obvious when the vegetation density increases to a certain degree，but appears as a local sand pile near the lower reaches of the single vegetation.

Abstract:Combining with the open caisson type of a port in Yantai，we apply a 1∶35 wave cross-section physical model to study the wave dissipation effect and wave impact load of open caissons with two column block superstructure and side opening superstructure. The results show that under the same wave condition，the wave attenuation effect of the increase of the opening rate of the caisson is better than that of the double column wave attenuation block. The biggest area of wave pressure of wave and open caissons of double column block upper structure is under the opening，while the biggest area of wave pressure of open caissons of side opening upper structure is near the opening. The wave force of open caisson of double column block superstructure is mainly affected by static water level，while the wave force of open caisson of side opening superstructures is mainly affected by the degree of inundation of wave surface.

Abstract:Based on the hourly data of 4 representative stations on the Chinese coastal areas from tidal table，all high tides（method 1）and one higher tide per day（method 2）are selected to calculate the tide riding water levels of different assurance rates，and the influence of the two methods on the engineering application is analyzed. The results show that method 2 can raise the tide riding water level and save the project cost，but it can shorten the navigation window period and increase the waiting time of ships，bringing inconvenience to the project running and operation. This influence is not obvious to the regular semidiurnal tide，but very obvious to the other tide types，especially to the irregular diurnal tide. For the engineering application of the irregular semidiurnal tide and the diurnal tide port area，the appropriate tide level can be selected comprehensively after detail analyses of the two methods combining with the engineering investment and the ship arrival frequency，which can not only meet the engineering application but also save the project cost.

Abstract:Wave transmission coefficient formula in Code of Design for Breakwater and Revetment only takes relative depth above the submerged breakwater crown into consideration. Based on numerical simulation using MIKE21 SW model，we carry out a study on the factors of wave transmission coefficient and analyze the suitability of the formula under different conditions. Results show that relative depth and relative width of the submerged breakwater crown are major factors. When 2≤B/H≤3 and hc/H≤1.25，the formula works well；When B/H≤1 or B/H≥4 or 2.0＞hc/H≥1.5，it is suggested to carry out experimentation to estimate the wave transmission coefficient.

Abstract:Aiming at the calculation method of the minimum design water depth of seaport anchorage，the mathematical model is studied. The UNDERKEEL model is used to study the vertical motion of ships under the action of waves，and the outputs can provide the amplitude response operator （RAO） of the vertical motion of ships. In the study，the water depth of the anchorage is calculated according to 1.2~2.5 times of the ship's draft （T） with a step length of 0.05T as the input parameter，and the bottom touching probability of different types and grades of ships under the influence of different wave height and wave period is obtained. According to the selected allowable bottom touching probability，the parameter relationship between the minimum design depth of seaport anchorage and the ship's draft is obtained. Finally，relevant research methods and calculation formula of the minimum design depth of seaport anchorage are given，which can provide a reference for the design project of seaport anchorage，and can be used as a reference for the preparation of relevant design codes of seaport anchorage.

Abstract:Dalian Bay Subsea Tunnel lands from the harbor basin between the pier 3 and 4 of Dalian Port. In order to provide dry working conditions for the construction of tunnel structure in the harbor basin，it is proposed to set up water stop structure around the harbor basin，and then drain the water. This working condition makes the force of wharf structure change. The wharf around the harbor basin was built by the Japanese in the 1930s and it's the object of cultural relics protection now，therefore，the stability of the wharf structure is analyzed according to this working condition. The analysis results show that the stability of the wharf structure is reduced due to the drainage construction of the harbor basin，so it is suggested to build a new temporary cofferdam outside the wharf before dewatering，which ensures the safety and stability of the wharf structure.

Abstract:Shantou Port is the main coastal port in China and the only main port in the eastern part of Guangdong Province. By analyzing the current situation of Shantou Port and the development of hinterland economy and industry，the significance of inland port layout of Shantou Port is put forward. On this basis，19 prefecture-level cities in Guangdong，Fujian，Jiangxi and Hunan as the candidate cities for the location of the inland port of Shantou Port are selected，and a multi-level index system of the candidate cities is further constructed，which involves three elements of geographical transportation，economic basis and cost factors. The location of inland port is discussed by analytic hierarchy process，and some suggestions for site selection and development are put forward.

Abstract:To increase the horizontal resistance of vertical pile wharf structure and avoid the difficulty in piling，we explore the possibility of using a new vertical pile wharf structure with horizontal braces based on comparative calculations. Adding the horizontal bracing between the vertical piles to form an interconnected structure，we can remarkably improve the overall rigidity of the structure to make up for the lack of horizontal load resistance of the vertical pile. Meanwhile，we avoid the difficulty in piling. The research result may serve as reference for the scheme selection in similar regions.

Abstract:Aiming at the problem of dynamic response to the fracture of 12° inclined pile heads at a harbor project in Shanghai，we carry out the strain monitoring of pile head of inclined pile at the site，perform finite element simulation of straight pile，6° and 12° inclined pile by ABAQUS software，compare the dynamic response of pile top before and after optimization of the pile hammer mass and falling distance，and obtain the influence of hammering frequency and hammering speed on the strain of pile top. The results show that under the same hammering load，with the increase of the inclination of the pile body，the tensile strain and compressive strain of the pile also increase，and the peak value of the tensile and compressive strain produced by the 12° inclination angle is the largest；increasing the mass of the pile hammer and reducing the falling distance to the pile top can reduce the strain at the pile top. The monitoring trend of the pile head strain is consistent with the change trend of the simulated value. The method of equating the impact force of the pile hammer with the triangular load by finite element simulation is reasonable.

Abstract:Taking the project of Baihetan large gear-rack vertical ship lift for example，according to different machine room types of ship-lift scheme，we establish a 3D finite element model of the large vertical ship-lift tower structure model which considers the interaction of foundation-tower-top machine room using finite element analysis software ANSYS，calculate the displacement and acceleration responses of the ship-lift tower and top machine room adopting the time-history analysis method，and compare the seismic response and whipping effect under different working conditions. The results show that the first mode of the tower structure is transverse vibration and the second is torsional vibration，and it is necessary to strengthen the torsional stiffness of the structure properly in the design of the tower structure. The whipping effect of large vertical ship-lift is obvious under the seismic action，and the separate machine room is more advantageous than the integrated machine room in whipping effect. The type of machine room should be selected reasonably when designing the ship-lift structure，and the top of the tower should be connected with a beam-slab structure.

Abstract:Laomukong hydroelectric-station is an important node for cascade connection of the Minjiang channel. The natural reach between the dam site and the tail of the Qianwei hydroelectric-station will be upgraded to grade Ⅲ channel through regulation measures at the same time as the construction of the station. In order to protect ecological and human environment，the planned normal water storage level of Laomukong is required to reduce by 1 m. Combining with channel regulation，we research the regulation measures that take into account compensation for the water head of the station and the navigation conditions by reducing the water surface slope of downstream reach of the dam. We apply the mathematical model to compare and select the schemes，adjust the flow direction and gradually optimize the diversion ratio，and propose the best recommendation scheme. The results show that the optimization scheme 3 can ensure that the flow conditions at the connection segment of the approach channel satisfy the requirements of specification，also reduce the downstream water level and compensate the power generation benefits.

Abstract:In recent years，multiple large-scale sand mining projects have often been carried out simultaneously in the same river reach of the lower Yangtze River. Compared with a single sand mining project，its impact on river flow conditions is more complicated. In this paper，a two-dimensional mathematical model is used to study the changes in water level，velocity，and diversion ratio of the channel under different sand mining schemes，and the superimposed effects of multiple sand mining projects implemented simultaneously are discussed. The results show that：1）The effect of a single sand mining project on the water level and velocity is mainly limited to the vicinity of the mining area，and the simultaneous implementation of multiple sand mining projects has reduced the water level and velocity variation caused by a single project. 2）After the implementation of a single project，the change of ebb tide diversion ratio is greater than that of flood tide diversion ratio，and the implementation of multiple projects has a small overlapping effect on the diversion pattern of the river section. 3）In addition，Tongzhousha west waterway mining project which located at the branch entrance section has the most significant impact on water flow conditions.

Abstract:The Minjiang Qianwei navigation-power junction is a vital link in the comprehensive development and construction of the Minjiang navigation-power development.As an important channel for Sichuan's large-scale transportation, Minjiang's water transportation is of great significance.In order to ensure the smooth flow of the Minjiang waterway during the construction period, especially in the second-stage cofferdam phase of the diversion during the construction period, the temporary channel is adopted for navigation, and the channel layout and route are adjusted greatly.Related parameters such as flow velocity, flow pattern and ship's navigation attitude are measured by hydraulic model test and ship model test.The results show that the original design scheme had insufficient water depth at the inlet during the dry season, and the flow pattern of the vertical cofferdam head appeared under large flow, which was extremely unfavorable to ship navigation.According to the test results, the corresponding optimization measures are proposed.After optimization, the upstream inlet is basically eliminated or improved during the low water period and the mid-flood stage cofferdam head flow pattern, making the overall flow velocity distribution in the middle of the design channel more uniform and improving navigation conditions，which provides a reference for the navigation of construction cofferdams of similar hubs.

Abstract:With the rapid development of ship upsizing, higher requirements are put forward for navigation facilities. At present, large ships mainly use the floating bollards of ship lock to dock, but there are some problems in the use process, such as non-standard mooring, too fast enteringof ships into the lock, unable to carry out safety warning of ships' entering the lock, and overload of the mooring system. Aiming at the structure characteristics of the floating bollard in Gezhouba Dam No.1 ship lock project, we carry out the finite element analysis for the stress of the ship lock floating bollard's upper structure by the numerical simulation method.According to the stress data of plates No.1～3 and tube No.4, we determine that the stress concentration and sensitive zones of the floating bollard are mainly near the dolphin.The result lays a theoretical basis for the field experiment scheme of the lock floating bollard's stress monitoring.

Abstract:In order to solve the problem of small fishing boat grounding on the top of submerged breakwater, we carry out the scheme design and experimental research on the heightening of the submerged breakwater.Based on the comparison of similar projects, we propose the scheme of directly stacking and heightening the submerged breakwater with Accropode, and carry out physical wave model test to compare the three design schemes.The experiment results show that it is feasible to heighten the submerged breakwater by stacking Accropode directly.In the heightening design, the block with the same specification as the lower layer can meet the stability requirements and is convenient for construction.When the crest elevation is less than 0.2 times of the design wave above the design high water level, 1.5 times of the weight of the outer slope protection block is usually not enough , and it should be more than 2 times.

Abstract:Based on channel regulation of creek mouth-bar rapids in the Lancang River Ⅳ level channel construction engineering, aiming at the problems that it needs to improve the level of the channel and it is necessary to guarantee the stability of navigation channel during the channel regulation process of creek mouth-bar rapids, this paper analyzes the cause of creek mouth-bar rapids from the water flow and sediment motion features, historical regulation and the incoming water and stone features, proposes building retaining dam for falling stone, building diversion and perennial dredging to improve the channel scale and maintain the channel stability.The results show that the engineering measures of retaining, guiding and dredging are used in the process of waterway regulation of creek mouth-bar rapids, which can solve the problems of creek mouth-bar rapids and provide references for the similar projects.

Abstract:The Three Gorges shiplift is arranged on the left bank of the Three Gorges project. The north side is adjacent to the Three Gorges ship lock and the right side is adjacent to the Three Gorges power plant. Compared with foreign shiplifts placed on artificial canals, the Three Gorges shiplifts are placed on natural waterways, and located between the Three Gorges ship lock and the Three Gorges power plant. Affected by the hub's flood control dispatch, power generation dispatch, and Three Gorges ship lock operation, the changes in water condition will have impacts on the operation of the Three Gorges shiplift. This paper analyzes the upstream and downstream water features of the Three Gorges shiplift at different times of the year. The method of data statistical analysis is used to quantitatively analyze the effect of water level changes on the adjustment of the working gate position of the upper and lower lock heads, as well as the law of water level fluctuations exceeding the limit and increasing the number of times of adjusting the water depth of the cabin. Finally, from the perspective of operation management, three operational response suggestions are put forward to tighten the contact with the dispatching department, strengthen the analysis of the use of water level data and further explore operational skills, with a view to improving the level of response to changes in water levels of the operating personnel.

Abstract:Taking Liutonghe tributary within the Xiluodu Reservoir for example, we study the determination method of navigable waters, waterway classification and design navigable stage within the high dam.Firstly, we demonstrate the starting point of the tributary waterway by analyzing the backwater length, water stage guaranteed rate, channel conditions, distribution of mineral resources, port planning, etc. Secondly, we determine the waterway classification of the tributary by analyzing channel conditions, navigable clearance dimensions of river crossing building，waterway classification of main stream, etc.Finally, we determine the design lowest navigable stage by calculating in sections. The design lowest navigable stage of perennial backwater area adopts the level of dead water.The design lowest navigable stage of fluctuating backwater area is comprehensively analyzed according to waterway regulation measures feasibility, waterway regulation measures investment, navigational guaranteed rate, and navigation capacity.

Abstract:In view of the excessive speed of cross-flow in entrance area of the approach channel of ship lock reconstruction in Jiepai junction project, we adjust the length of water diversion wall and the elevation of hanging plate, apply flow condition test to obtain a reasonable and feasible general layout optimization scheme of approach channel.Aiming at the problem that the geological condition of the downstream approach channel changes and the mixed structure used in the original design is no longer applicable, we carry out the economic and technological comparison between the gravity structure and the gravity pier+hanging plate structure, and determine the changed scheme.The results show that the gravity structure has strong anti ship impact ability, simple construction and slightly higher investment, which can be used as the recommended scheme.

Abstract:The traditional construction of inland channel focuses on functions such as shipping, irrigation, flood prevention and drainage.With the continuous development of the economy and society, people are paying more attention to the ecological beauty, the landscape beauty, the harmony between man and nature in addition to its traditional functions.Taking an inland channel regulation project as an example, we aim at the project characteristics such as the large difference between the plan alignment and status quo of the linear, the high requirements of the protection of cultural relics and ecological landscape, and the large pressure on environmental protection, study on the key technical points of the channel's plane alignment, bank protection structure, cultural relics protection, ecological landscape, ship energy conservation and environmental protection, and put forward the design countermeasures, such as natural revetment lines, ecological revetments, cultural relics protection schemes for rectangular channel sections, energy-saving and environmentally friendly assembly revetment construction schemes, etc.Through these countermeasures, the ecological beauty, landscape beauty, harmony between man and nature can be achieved in the channel construction.

Abstract:Yakou hydro-junction in Hanjiang River is navigable river junction.The navigation problem should be properly dealt with during the construction period.We propose corresponding navigation scheme combined with phased construction scheme, adopt the narrow channel in the first construction period so as to avoid the adverse effects caused by the broken navigation, and use the established lock in the second period to realize the combination of temporary navigation and permanent building.In view of the navigable flow conditions during the construction period, we establish a two-dimensional hydrodynamic numerical model to calculate and analyze the flow pattern under various flow conditions.The results show that the navigable flow conditions of two construction periods satisfy the related requirements.

Abstract:In view of the complicated navigation environment in Yingongzhou channel, limited channel capacity and frequent ship accidents, we use the data analysis method to analyze the influence of ship traffic flow characteristics and hydrology-weather conditions, and point out the key problems faced by Yingongzhou channel.Based on the analysis of the historical evolution and field investigation of the southern branch channel of Jiaobei waterfront, we propose the idea and planning of constructing the southern branch of Jiaobei waterfront into the Grade 3 channel of the inland river, as well as the technical engineering measures to be taken. By analyzing the influence of the opening of new channel on the navigation environment in Yingongzhou channel, we draw the conclusion that the opening of the southern branch channel of Jiaobei waterfront can improve the navigation conditions, enhance the passing capacity and reduce the safety risk of Yingongzhou channel.Furthermore, we carry out an analysis on the benefits of safety, economy and environmental protection and other advantages, and propose suggestions to carry out more in-depth study for the opening of the southern branch channel of Jiaobei waterfront.

Abstract:For the full utilization of the water depth conditions of the Yangtze River Jiangyin waterway, we carry out a study on the technical feasibility and utilization plan.Based on the 2D mathematical model calculation, review of waterway conditions, and analysis of tidal level cumulative frequency, we come to the conclusions as follows.In the past ten years, Jiangyin waterway had a water depth of not less than 13.60 m and a certain available tidal level, and it was technically feasible to increase the draught to 12.0 m.Based on the case analysis of the use of waterway depth in the Yangtze River, two ideas for using the waterway depth in Jiangyin waterway are proposed, which provide scientific and reliable new methods for deepwater channel maintenance management, and promote innovation of channel maintenance management.

Abstract:According to the geologic conditions of Jinggangshan navigation-power junction dam site, we put forward two arrangement plans of “lock and power plant at the same bank or different banks”.Under the principal of optimal flood control，navigation conditions, construction conditions and time limit for a project and project investment, we compare the general layouts and recommend the overall layout scheme, i.e., permanent lock at the left bank and power plant & fishway at the right bank.Using hydraulic integral model and ship model test, we study the key factors such as hub discharge energy dissipation, the navigation flow condition at the entrance area, power station flow condition of the recommended layout, demonstrate the general layout scheme and put forward improvement measures.The research process and conclusion may serve as reference for the general layout arrangement of low water head navigation-power junction.

Abstract:Aiming at the problem that the test results of secondary deformation modulus in some overseas projects are very different because of using codes of different countries, we carry out comparative study of Chinese, German and French codes.We compare the test device, test process, calculation formula and result analysis etc, and analyze the application scope of the three specifications combined with engineering examples.The results show that the codes of China and German are relatively detailed, and test process and result calculation of them are consistent.The French code mainly defines principle, direction, and norms are more general which is not conducive to guide field test.The result of secondary deformation modulus using French code is conservative for sandy soil foundation.It is suggested that when undertaking overseas projects which need to adopt secondary deformation modulus to evaluate treatment effect of sandy soil foundation, Chinese and German codes should be chosen firstly, and it is not recommended to select the French code.

Abstract:The total area of proposed artificial island in Dalian is 21 km2，and the foundation soil above bedrock is widely distributed with thick cohesive soil and muddy soil.In order to satisfy the control of foundation settlement, we study the settlement and consolidation characteristics of the foundation soil by tests.By means of in-situ pressure meter test at sea, cone penetration test and laboratory test, we obtain the consolidation compression indexes of foundation soil, compare and analyze the consistency and reliability of different consolidation parameters, and predict the settlement characteristics of the foundation by calculation.The results show that the consolidation indexes obtained from pressure meter test, cone penetration test and laboratory test can confirm each other.After reasonable foundation treatment, the predicted post construction settlement can satisfy the use requirements.The analysis results of deformation characteristics of foundation soil are reliable and can be used as the design basis of artificial island construction project.

Abstract:In soft soil improvement projects, analysis of measured settlement data is often limited to predication of ultimate settlement and consolidation degree.Based on the Asaoka method, complete procedures for dynamic design of soft soil improvement can be established by using the measured settlement data.This paper summarizes the method of calculating the ultimate settlement and consolidation degree under preloading by Asaoka method, and puts forward a practical method for back analysis of soil parameters such as horizontal consolidation coefficient and compression index，and prediction of preloading period.Its application is introduced through an engineering example.The procedures can make full use of the measured data, and dynamic design for soft soil improvement is realized, which are beneficial for design and construction.

Abstract:Reclamation is applied in port construction, artificial island and so on, which has the characteristics of large engineering volume, long transportation distance and high cost.In order to obtain accurate figures in reclamation sand volume calculation as far as possible, the detailed calculation method of reclamation sand volume based on multi-beam measurement data and Matlab programming is introduced.According to the foundation treatment effect of vibroflotation and drainage board, the consolidation and surcharge effects of dredger fill sand are inversely deduced, thus the amount of dredger fill sand is accurately calculated and the accurate handover elevation of reclamation fill is given.In the practice of Panama Amador cruise terminal project, the amount of reclamation accurately calculated can save about 70, 000 m3 compared with the traditional calculation method.

Abstract:Aiming at the problem that the rock cutter load of cutter suction dredger in the construction process is difficult to quantitatively determined, we establish the tooth coordinate model, determine the tooth cutting condition according to the construction parameters, apply the load model of the single tooth cutting rock to build the overall load analysis model of cutter, calculate transverse force, vertical force, longitudinal force and power of the cutter under different rotational speed, the transverse velocity and attitude angle and thickness of mud conditions, and analyze each working with forward and reverse cutting of the cutter.The results show that the rotation speed and transverse movement speed of the cutter have a positive correlation with the power of the cutter, and the attitude of the cutter and the thickness of the mud layer have the greatest influence on the cutter load, no matter in forward or reverse construction.

Abstract:In order to further improve the construction efficiency and fully utilize the construction capacity of the trailing suction hopper dredger, taking the maximum production during the trailing process of the trailing suction hopper dredger as the optimization goal, the pump cavitation margin and the pipeline critical velocity as the restrictions, and the flow rate that is most well-known and easily controlled by the dredge operators as the optimization variable, this paper establishes a calculation model for the flow corresponding to the maximum production of the trailing suction hopper dredger in trailing process (called the optimal flow rate) in order to aim at expanding dredger trailing optimization theory and operation methods.The optimized calculation results of the model and the actual production data are comparied and analyzed, and the results are in good agreement, indicating that the calculation results of the model are accurate and reliable.In addition, the variables required for model calculation are easy to collect, the optimization calculation results (control target, flow) are clear, and the dredger operators are familiar with the flow control and manipulation.Therefore, the model can not only provide reference for construction design and dredging operations, but also be easy to popularize and apply.

Abstract:At present, the evaluation of the dredging effect of the drag suction dredger mainly relies on the common sense experience of the construction personnel, such as sacrificing a large amount of construction time in exchange for maximizing the yield of sand, but it causes a higher cost of single earthwork.Combined with the measured construction data of the trailing suction dredger in Xiamen Port, a multi-index dredging performance evaluation system is constructed, and the weight of each performance index is determined using the entropy method.The research shows that the multi-index evaluation system can more comprehensively and objectively reflect the dredging performance of the drag suction dredger, and it is consistent with the test results of the auxiliary decision-making system of the dredger.

Abstract:Quality detection is an important link to ensure economic and social benefits of the project.The correctness of the detection result relates closely to the normal operation of the project.Single-beam sounder and multi-beam sounding system are the main measurement measures for the engineering quality detection, and the difference between their measurement results will affect detection result.Qualitative and quantitative analyses are carried out to the measurement data before and after construction by the two measurement measures and the detected sectional data of the difference, and the results show that there is not much difference of measurement data between the single-beam and multi-beam before construction.After construction, riprapping increases the underwater terrain's complexity and the difference of measurement data by the two measures.In addition, the angle and route deviation of the single beam increase the detection errors.Based on the research results, we put forward suggestions on improving the accuracy of the single beam detection.

Abstract:With the development of dredging industry and environmental protection requirements in the world, trailing suction hopper dredger will face more long-distance, deep-sea and far-sea projects in the future.In view of the problem that the cost of transportation and navigation greatly increases in such projects, we take “Tongtu” ship as an example according to the theory of absolute economic speed and relative economic speed, use the load characteristic curve of diesel engine and the construction characteristics of trailing suction hopper dredger, analyze the data relationship among the load, oil consumption, production value, cost and other indexes in the process of transportation and navigation, and form the real ship calculation model when carrying and sailing under the working condition based on the relationship curve.The results show that the calculation model is helpful to make full use of the economy of the trailing suction hopper dredger in the long distance and far-sea engineering, and improve the engineering benefit.

Abstract:The silty cohesive soil has large transfer resistance during the bow blowing construction of medium and large suction hopper dredger, which will cohere together and become spheres to block the dredging pipeline, and then will influence the efficiency of bow blowing construction.On the basis of systematically analyzing the existing domestic and foreign mud pipeline blockage prevention method, we develope a kind of anti-blocking equipment and implementation methods of pipelines of suction hopper dredger and carry out the field test research depending on the dredging and fillinging in Qingdao Port.The results show that compared with the traditional technology, this method is easier to construct, fast and flexible, operability, economical, and safe and reliable;the silty clay dredged material bow blowing operation can be carried out under short-distance, medium-long-distance and long-distance conditions;the efficiency of the silty clay dredged material bow blowing operation has been greatly improved.

Abstract:The rapid pile sinking is a common event during the pile foundation construction, especially at the thick soft soil layer overburden.The problem cannot be solved by the conventional measures such as reducing the weight of pile shaft or the weight of hammer.Combining with the engineering example, we analyze the production mechanism of the rapid pile sinking, innovatively adopt the improvement measure of the pile driver hammer cage, and test the pile sinking quality.The results show that the improved pile driver hammer cage is used when the rapid sinking occurs during the pile foundation construction at thick soft soil layer overburden, the pile is intact, the pile tip can reach the design elevation, bearing capacity of pile can satisfy the design requirements and the quality of pile driving can be guaranteed.The measure is useful.