Abstract:The extreme waves generated by the typhoon cause the overtopping of the sloping seawall. However，the existing empirical formulas for calculating the wave overtopping discharge have the applicability. In order to find out the formula for calculating the amount of overtopping of the sloping seawall in Zhoushan area under typhoon weather，we solve the Navier-Stokes and k-ε equations based on the VOF method，establish the numerical wave flume with boundary velocity wave generation and wave damping absorber，build the model of slope seawall in the flume，and simulate the condition of regular waves acting on slope seawall under the typhoon weather by changing the relevant factors affecting wave overtopping discharge. We compare the numerical simulation results with the experimental results of the physical model，analyze the quantitative relationship between each factor and the overtopping coefficient，and propose a new empirical formula for calculating the overtopping coefficient. The results show that the empirical formula presents the logarithmic relationship between the steepness of outburst wave and the wave overtopping discharge. The larger the relative water depth is，the larger the relative height of the dike is，and the smaller the μ′ value is，the smaller the wave overtopping is.

Abstract:On the study of wave distribution in shallow water near the shore，Grukhovsky gives an empirical wave height distribution formula from deep-water to the entire shallow water area（η＞2），but the applicability study of the formula after wave breaking is lacking. Based on FLOW-3D software，we carry out a simulation of deep-water irregular wave propagating to slope topography breaking area，verify the consistency between the wave height distribution along the path with the test value，and simulate the change of wave height distribution along the way when the wave propagates from the finite water depth to the near shore breaking area under the condition of slope topography of 1∶30. The results show that under the condition of this slope and the relative water depth η＜2.75，there is a large error and the empirical formula is inapplicable. The ratio of each cumulative rate wave height to the average wave height in the breaking area shows a decreasing trend as the relative water depth becomes smaller. The values of the empirical formula compare with the numerical experiment values，these of the big wave are larger and these of the wavelet are smaller.

Abstract:Based on MIKE 21 Mooring Analysis software，we study the motion of moored ships subjected to irregular waves with different periods and incident angles. The results show that the variations of motion of the moored ship interact with each other for different wave incident angles and periods. Sway，roll and heave motions of the moored ship increase with the increase of the wave incident angle，and the effect of the roll resonance decreases with the wave incident angle away from the direction of 90°，the heave motion change little when the wave incident angle is close to the direction of 90°or 0°. When the incident wave period is long，the surge motion and yaw motion first increase and then decrease with the increase of the wave incident angle，and generally have a peak value when the wave incident angle is 60°.

Abstract:through collecting and sorting out the relevant researches on breakwater overtopping in recent years，this paper summarizes the influence of overtopping factors，the deduction and demonstration of overtopping calculation formula，overtopping numerical simulation and overtopping standard. The existing results show that：most of the factors of overtopping are focused on the study of conventional factors，including wave height period，dike top elevation，slope shoulder width and armor block，while the study of other factors such as flow，wind speed，wave spectrum and water properties is relatively less；the study of overtopping calculation formula mainly focuses on three aspects：the factors affecting overtopping，the comparison and selection of overtopping formula，and the derivation of formula. In the aspect of numerical simulation，RANS equation and RNG model are mostly used Based on k-ε turbulence model and VOF method，fluent and other mature softwares are used to simulate the overtopping process or predict the overtopping amount. Machine learning algorithms such as neural network are more and more used in the numerical simulation of overtopping amount. With the deepening of the above research，the overtopping standard has gradually improved，and the applicability has been strengthened to a certain extent.

Abstract:Tidal current asymmetry plays an important role in the net sediment transport and morphological evolution in the delta，and large-scale sand excavation activities in the Pearl River Delta（PRD）have caused significant descending of the riverbed in recent years，so it is important to study the spatial and temporal variation patterns of tidal current asymmetry in the PRD after riverbed descending. This paper establishes a two-dimensional hydrodynamic model which using topographic data of the PRD in 1999 and 2010 to simulate the hydrodynamic process in the Pearl River estuary network during the dry season. Using nonstationary harmonic analysis method to decompose velocity signals，the skewness method is used to quantify the contribution of tidal combinations，residual flow and interaction between tidal components and residual flow to tidal current asymmetry. The study shows that：1）Tidal current asymmetry is ebb dominant in the PRD due to the influence of the residual flow. 2）After riverbed descending，contribution of tidal combinations to tidal current asymmetry shows increasing trend，tidal current asymmetry weakens in the lower reaches and strengthens in the middle and upper reaches，and the change of the middle and upper reaches of the PRD is greater than that of the lower reaches.3）Changes in the interaction between tidal components and residual flow are the main cause of this phenomenon.

Abstract:We propose a new method to calculate the tide riding water level only using the high and low tide data. Based on the tide table’s data of the high and low tide data and hourly tide level data from tidal stations of different tide types in China，we use the calculation results by the standard method to verify the results of this method，and analyze the calculation error from multiple aspects. The results show that most of the new method’s errors are within 10 cm，and the maximum error is about 20 cm in the area which is obviously impacted by runoff and shallow water tidal component. Thus，the results of the new method can meet the engineering requirements. This method has clear physical meaning，simple formula and can be easily solved by calculator or Excel software. This method can be used to calculate the tide riding water level in the sea area lacking hourly tide level data.

Abstract:Due to underwater complex environment，pile inclination and large measurement error，the determination of underwater cylindrical pile position with high accuracy，low cost and high efficiency has always been a difficulty in offshore engineering. Therefore，this paper proposes a high-precision determination method of underwater cylindrical piles and their spacing distances based on MBES（Multi-beam echo sounder）point clouds. Firstly，we has obtained positions of pile and seabed with low cost and high efficiency using this method. Then，considering the geometric information（normal vector and elevation）as well as pile attribute information，we realized the effective extraction of pile point clouds using a comprehensive threshold segmentation method. A comprehensive determination method of pile center position considering pile shape and measurement error has put forward to realize the high precision determination of pile position and pile spacing. The method in this paper has been verified by practical engineering，and the determination accuracy of pile position and pile spacing is better than 5 cm.

Abstract:We present the calculation formula of berthing energy in unified facilities criteria，compare the similarities and differences of selection of design parameters and calculation results in unified facilities criteria（UFC），BSI standard and Chinese standard，and further study the eccentricity coefficient Ce and virtual mass coefficient Cm. The results show that UFC considers the influence of the under keel relative clearance on berthing energy in Cm，and the calculation result of Cm in UFC is similar to that in ship model test. The berthing energy in UFC is higher than that in BSI standard，while it is the lowest in Chinese standard. Ce and Cm are basically constants in different ship types，and they vary little in relation to tonnages.

Abstract:In order to solve the problem of insufficient filtering accuracy of common fixed resolution surface，we propose a multi-beam filtering method based on adaptive multi-resolution surface. In the survey condition of steep ridge and small target protrusion with the change of large terrain，the adaptive multi-resolution surface automatically enhances the resolution of multi-beam bathymetric surface for the local area with characteristic terrain or surface features according to the change of terrain slope，so as to obtain a more accurate seafloor surface model. Based on this surface model，automatic filtering can be carried out，so as to retain more complete underwater terrain feature and small target，and the method is compared and verified. The results show that under the condition that most of the noise is effectively filtered，the integrity rate of terrain features and small objects can reach more than 98%. The multi-resolution surface and filter algorithm built in this paper can improve the accuracy of multi-beam filtering.

Abstract:In terms of the wave dissipation performance of a new type of pile foundation permeable breakwater with a wave dissipation plate，this paper studies the reflection coefficient，transmission coefficient and wave energy distribution of the new type of permeable breakwater under wave action. Using FLOW-3D numerical simulation method，the reflection coefficient，transmission coefficient and wave energy distribution of the permeable breakwater are obtained when the opening ratio，relative water depth and inclination angle of the wave dissipation plate change. The results show that：1）The new type of pile foundation permeable breakwater with a wave dissipation plate has good wave dissipation performance. The smaller the opening ratio is，the greater the reflection coefficient is and the smaller transmission coefficient is. 2）The design scheme of 10% opening rate，0.85 relative water depth and -15° inclination angle has the best effect，and the wave energy transmission coefficient of the new type of permeable breakwater is only about 17%.

Abstract:Based on the multi-intelligence simulation modeling method，we establish the whole process simulation model on ship’s in/out of relative areas of Lianyungang Port，by which we quantitatively evaluate the possible long-term impact on navigational induced by the LNG terminal，and compare the result with existed research conclusions. By comprehensive comparison of essential factors including waterway conditions，location and rear city distance，navigation impact，etc.，we propose the recommended site of the LNG terminal of Lianyungang Port. The analysis method and conclusion proposed provide technical support for the layout planning of regional LNG terminals.

Abstract:The floating breakwater has the advantages of not affecting material exchange in sea area and low cost. But the disadvantages of high requirements to the structural connection and mooring system of the floating breakwater limite its application and developmet，inorder to overcome these disadvantages and give full play to the effect of wave elimination of the floating breakwater，we verify the effect of wave elimination of the new steel structure of the floating breakwater by physical model test with large-scale wave test flume. The correlations between the transmission coefficient（Ct）and the relative draft（t/D），the relative water depth（t/L）and the relative width of the breakwater（W/L）are studied. The results show that when the wave period is less than 6 s，the transmission coefficient（Ct）of the new steel structure floating breakwater can be less than 0.5，which verifies the effect of the new steel structure floating breakwater.

Abstract:The determination of the slope revetment top elevation often has a great impact on the overall cost of revetment project. In this paper，based on the engineering example，revetment top elevation is analyzed according to the theoretical formula，in which the control standard of overtopping is mainly analyzed. After determining the revetment top elevation according to the control standard of overtopping，the action distance of overtopping tongue is further analyzed. Finally，the theoretical calculation results of overtopping and action distance of overtopping tongue are verified according to the physical model test. The analysis results show that：1）For the slope revetment top elevation，the reasonable overtopping control standard should be determined according to the actual protection function. 2）At the same time，the action distance of overtopping tongue should be analyzed to provide the basis for the site layout behind the revetment.

Abstract:Comparing to the conventional oblique pile，all-vertical-piled structure bears the horizontal load completely by its own bending resistance，the pile diameter is larger，the vertical bearing capacity is not fully developed and investment is higher under the same stress condition. Aiming at this problem，we propose a new type of all-vertical-piled pile structure with horizontal steel truss，take the certain engineering mooring pier as an example，use the space model for calculation and analysis，and determine the optimal structure scheme，and apply the horizontal steel truss to connect the pile foundation in the middle position of pile foundation. The results show that adding horizontal steel frame can increase structural stiffness，reduce pile diameter，control structural displacement，give full play to the role of rock socketed pile，and has obvious economic advantages.

Abstract:Concrete square piles are mostly used in the pile foundation of the old high pile wharf. After long-term operation，the pile foundation generally has different degrees of damage defects，which seriously threaten the safety and durability of the structure and affect the normal use of the wharf. It is urgent to repair and reinforce the damaged pile foundation. At present，the repair and reinforcement of concrete square pile usually adopts such measures as pasting carbon fiber cloth，increasing pile cap，local outsourcing，steel hoop，glass fiber sleeve，etc.，which have achieved good engineering results. This paper discusses the specific implementation scheme，characteristics，key points and applicable conditions of each measure to provide reference for reasonable selection. The application results show that in view of the damage defects of prestressed concrete square piles of the old high pile wharf，according to different damage characteristics and construction conditions，the reasonable selection of repair and reinforcement measures can meet the safe，reliable，economic and reasonable maintenance requirements.

Abstract:Since the 175 m tiral impoundment of the Three Gorges Reservoir，the amount of sand entering the reservoir has been greatly reduced，and there is a certain difference between the sediment scouring and silting characteristics of the reservoir and the research achievements in the argumentation stage. In response to this problem，based on the prototype observation data of sediment in the channel of the Three Gorges Reservoir since the impoundment of the Three Gorges Reservoir，we systematic analysis the characteristics of inflow-outflow of the water-sediment characteristics，and the sediment scouring and silting situation in the reservoir area and the sediment deposition distribution. The results show that：1）The amount of sand entering the reservoir is significantly reduced than expected. 2）The siltation is mainly concentrated in the perennial backwater area below Qingxichang，and the river sections with a large amount of siltation and strong siltation intensity are mainly open and branched river sections in the perennial backwater area. 3）Sediment silting presents the characteristics of flat silting in main channel and asymmetric siltation dominated by siltation on one side.

Abstract:Step-shaped spur dike is widely used in waterway regulation，but its flow structure is still not fully studied. Based on the PIV indoor flume test，we discuss the distribution of dimensionless longitudinal time average velocity u+，turbulence intensity T+u，Reynolds stress R+ and turbulent kinetic energy E+ in the stepped spur dike area. The results show that the longitudinal section of spur dike flow can be divided into downstream area，reflux area and transition area. The high velocity area of u+for each profile from the inside of spur dike to the head of the first step spur dike is located in the upper part of the dam crest，while the low velocity area and the reflux area are located in the lower part of the dam crest，the u+ of section outside spur dike variation first increases and then decreases. Affected by the flow over the dam crest，T+u of vertical line upstream of spur dike change obviously with y+，while T+u of vertical line downstream of spur dike change relatively gentle with y+. The high value area of R+ is located near the dam crest and is in a strip shape. When the discharge is small，the vertical change of R+ with y+ is relatively gentle，and the distribution curve of R+ near the dam crest is in “S” shape. The change of R+ in the upstream of spur dike is intensified with the increase of discharge. The high value area of E+ diffuses from the top of the dam to the bottom of the flume and water surface in a triangular shape，and E+ increases with the increase of discharge.

Abstract:Based on the measured hydrological data and several topographic maps，we analyze the back silting characteristics of 35，000 DWT navigation channel at Sheyang Port. The results show that the sea area where Sheyang Port is located is influenced by the sediment transport of the ancient Yellow River Delta，which has a high sand content and provides a rich source of sediment for the siltation of the channel；the annual siltation of the inlet channel is 9.95 million m3，of which the section covered by the guide dike accounts for 93% of the total siltation of the channel，and the average siltation intensity of this section can reach 5.0 m/a，which is higher than that of the open sea section of 0.6 m/a. The siltation of the channel in the section covered by the guide dike is mainly due to the high sandy water brought in during the high tide period，which also contributes to the siltation of the channel.

Abstract:To solve poor deceleration function and poor ecological effect of conventional ecological slope protection structure，based on the three-dimensional energy dissipation thought and pore theory of ecological environment preservation，a new ecological slope protection structure，three-dimensional reticulation slope protection structure，are developed. Through generalized flume experiment，the stability of ceramsite concrete and plain concrete under action of wave current coupling are studied，and relevant measures to enhance the structure stability are proposed. The new slope protection structure could be used in the channel regulation and slope protection engineering in the middle and lower Yangtze River and tidal reach，which provides new materials for the channel regulation theory，and would promote the technological innovation and ecological technological progress of channel regulation.

Abstract:The second phase of the Huai’an Water Control Project needs to build an additional aqueduct，which may affect the navigation conditions after forming a long-distance navigation aqueduct with the first phase aqueduct. Aiming at the problem，a three-dimensional mathematical model is established，and the navigation conditions of the aqueduct before and after the construction of the second phase aqueduct are simulated and analyzed by selecting two operating conditions under the most unfavorable combination of ship types. They are the operating conditions of the upstream and downstream ships in the opposite direction，and the energy dissipating grid is arranged or not.Conclusions are drawn：1）The wave height after the completion of the second-stage aqueduct is increased by about 20% without the energy dissipating grid，and the wave height is reduced to 7% after the energy dissipating grid is added. 2）The cross flow is at 0.05~0.20 m/s，and the Froude number is far less than 1. The bow deflection angle is 0.64°~1.74°. They have little change from the current operating conditions. 3）The long aqueduct composed of the first and second phases has good navigation conditions and will not cause adverse effects on the navigation of the ship.

Abstract:Based on the measured river topographic data of the mainstream of the Beijiang River in 2011 and 2020，the evolution law of the Beijiang River main stream in recent ten years is quantitatively analyzed from the aspects of riverbed elevation，thalweg elevation，water surface width，river facies coefficients and changes in riverbed volume. The results show that：1）The reach from Shaoguan to Mengli water conservancy project is silted，and the reach from Mengli water conservancy project to Sixianjiao is scoured. 2）The average fluvial facies coefficients of the two reaches from Shaoguan to Mengli water conservancy project are increasing，while the average fluvial facies coefficients of the four reaches from Mengli water conservancy project to Sixianjiao are decreasing. 3）The main factors affecting the evolution of the Beijiang River main stream include sand mining，reservoir construction，soil erosion，waterway improvement projects and national and local policies，among which sand mining is an important factor.

Abstract:According to the planning，the section from Longxikou to Yibin in Minjiang River will reach Grade III inland waterway standard through waterway regulation. According to the historical data，the 95% flow rate of the section over the years can only reach 662 m3/s. However，with the construction of large hydropower stations such as Zipingpu and Pubugou in the upper reaches of Minjiang River in recent years，the navigable flow of the reach has been greatly affected. Based on the runoff and sediment series of Gaochang hydrometric station before and after impoundment of Zipingpu Hydropower Station，we analyze the influence of Zipingpu and other large hydropower stations on the water and sediment characteristics of the river reach，and know that the amount of incoming sediment is obviously reduced，the annual distribution of runoff is homogenized，and the discharge is obviously increased in the dry season. Especially，when the multi-year guarantee rate is 95%，the discharge is increased by 166 m3/s and corresponding water level is increased by 0.21 m. The research results can provide flow support for the research reach to reach Grade III inland waterway standard.

Abstract:The fluctuation zone of Xialuoqi reservoir section is prone to bank slope erosion due to nearshore sand mining and river water scouring. The ecological environment in the area has been irreversibly damaged. To find out a comprehensive treatment method considering environmental，ecological and economic functions，the paper proposes two treatment schemes，i.e. traditional slope ecological revetment（TSER）and Tera anchor pad ecological revetment（TAPER），and compares the advantages and disadvantages of them in terms of six aspects，including construction technology，revetment effect，ecological restoration effect，construction period，construction site conditions and later maintenance cost. It is concluded that TAPER is more suitable because of its advantages of simple construction technology，live adaption for plants，broad green coverage，and meeting the prevention needs of the bank slope erosion，and is also suitable for other soil banks or rock banks in rivers and lakes prone to slope erosion. Thus it is expected to be further promoted and applied for bank slope reinforcement and ecological restoration.

Abstract:Guichi channel is a multi-level and multi branching channel. In recent years，the beach channel pattern has changed significantly，forming a double channel pattern，and the channel conditions are developing in an unfavorable trend. This paper analyzes the recent riverbed evolution and navigation obstruction characteristics. Following the regulation idea of restricting the development of north port，stabilizing the branching pattern of branch，and consolidating the position of main branch and main channel of China port，this paper proposes a preliminary channel regulation scheme. Through the fixed bed and movable bed model test，the scheme effect is compared and analyzed，and the test results are compared. The results show that the scheme of comb-type beach protection for the head of Chongwenzhou bar and bottom protection for Xinglongzhou right channel in Beigang is better.

Abstract:Inland aids to navigation mark the boundaries of navigable waters and play a significant role for ensuring the safe navigation of inland ships. Considering different failure modes of aids to navigation，we propose a status recognition model based on BP-DS evidence theory，use two BP neural networks to train the basic attribute data and environmental factor data，calculate the independent evidence values，and further apply the DS evidence theory to realize the decision-making fusion of aids to navigation operation state recognition results. The results show that the accuracy of status recognition model of aids to navigation based on BP-DS evidence theory is more than 80%，which is higher than the traditional empirical threshold judgment method.

Abstract:The ship locks are critical parts of the waterway，and the gate is an indispensable part of the lock system，which brings great losses to the waterway transportation once it fails，so it is necessary to monitor the status of the lock gates. The vibration monitoring is common in existing methods and it mainly concentrates on the vibration when the gate works，however，it is single because of lacking tilt and working state of the gate caused by vibration. In view of the problems，a multi-sensor fusion status monitoring system of the lock gate is designed which based on the finite elements analysis and vibration monitoring. The system can conduct the real-time vibration frequency，angle monitoring and long-term tilt state monitoring，and provide a multi-sensing information fusion method for the gate status monitoring. The practical application in the Jianbi locks in Jiangsu Province proves that the system can acquire and master the working status of the lock gate in real time，and safely guarantee the routine work of the locks.

Abstract:The basic architecture of“Junyang 1”logging system is analyzed. The data post-processing program of the logging system is designed and developed based on Python. The operation parameter database of the suction harrow is established，and the visual display and interactive function of the data are realized. The algorithm based on time sequence and time is put forward to judge the working state of the suction harrowing vessel. Taking the Colombo Port City Development Project in Sri Lanka（2017—2018）as an example，the algorithm of the program was tested with statistical data of daily construction. The results show that the algorithm has good robustness.

Abstract:Aiming at the problems of complication and heavy drawing workload of the triangle gate，based on the BIM technology application experience of Qinhuai River Honglan ship lock and Weicun hub expansion and reconstruction project，the triangle gate is disassembled to seven parts according to the structural characteristics and construction sequence，and the lumped parameter model is established by setting the overall parameters and local parameters. Through continuous debugging，the engineering templates are created with simplified input conditions and variable parameters，and the engineering quantity is extracted based on UDF. The batch processing of similar components is used by knowledge engineering rules capture skillfully，which greatly improves the modeling efficiency and realizes the automation，standardization and parametric design of triangle gate.

Abstract:Aiming at the problem of the low efficiency of hard clay excavation，it is necessary to study the cutting mechanism of the clay. By using the method of numerical simulation，we establish the 3D model of cutting hard clay by cutter tooth，build the soil constitutive model by the nonlinear elastoplastic model，realize the numerical simulation of hard clay physical process based on the explicit integral algorithm and chip simulation unit damage failure criterion of hard clay，analyze the status of soil deformation in different times，and obtain the cutting force of the tooth. The results show that as the selected hard clay parameters，when the selected cutting thicknesses are 50mm，100mm and 150mm，the errors of numerical simulation and cutting experiment are 27%，9% and 5% respectively. Considering the inhomogeneity of soil，it is suggested to express the cutting load with the peak value of cutting force obtained from numerical simulation.

Abstract:The foundation soil of inland port is mostly unsaturated soil under the action of underground runoff and rainfall infiltration，and its soil water characteristics affect the stability of port foundation. Taking the unsaturated cohesive foundation soil of Huaibei port in Anhui Province as the research object，we carry out the soil-water characteristic curve（SWCC）tests under different initial moisture content，initial dry density，vertical stress and dry wet cycles. The results show that the effects of initial dry density and vertical stress on SWCC of unsaturated cohesive foundation soil are similar，and they have a greater impact on air intake value，initial gas value，dehumidification rate，moisture absorption rate and residual saturation；the effect of initial water content on soil dehumidification and moisture absorption rate is small，and with the increase of initial water content，air intake value，gas absorption value and residual saturation increase；with the increase of dry wet cycle，the effect of initial water content on SWCC of unsaturated cohesive foundation soil increases the attenuation of the inlet and outlet values gradually weakened with the increase of the pressure. Combined with the soil-water characteristics of foundation soil，we modify several commonly used SWCC models to simulate SWCC under different working conditions，and obtain the recommended model for unsaturated cohesive foundation soil of Huaibei port by scoring. The research results may serve as reference for the study of soil-water characteristics of unsaturated cohesive foundation soil and stability of port foundation under different working conditions.

Abstract:The calculation provisions in Chinese design codes for excavation for determination of the embedded depth of cantilever retaining structure are disputed and the safety margin is not sufficient. The requirements in relevant Euro and British standards are theoretical correct but the traditional simplified method results in a conservative embedded depth. We summarize the basic rules for determination of the embedded depth of cantilever retaining structures，and analyze the problems of the relevant principles in Chinese and international design codes for excavation. We suggest that the partial factor method together with the strict load equilibrium and moment equilibrium conditions is used to calculate the embedded depth of cantilever retaining structure. The resulted embedded depth is larger than that calculated by Chinese standard，and is smaller than that calculated by the internationally accepted simplified method. The improved method is more rational in theory and can achieve a safe and economical design in practice.

Abstract:Under the action of water circulation，the sandstone foundation of inland port leads to the deterioration of rock mechanical properties and threatens the long-term stability of port foundation. In order to explore the mechanical characteristics and energy damage of sandstone under dry-wet cycle，we carry out the triaxial compression test under different dry-wet cycle times. The results show that with the enhancement of dry-wet cycle，the mechanical properties of sandstone gradually decay，the attenuation amplitude basically converges when the number of cycles reaches 15 times. The accumulation degrees of deterioration of sandstone peak strength，residual strength，elastic modulus and deformation modulus have the similar law，the accumulation rate of dry-wet cycle is faster when 0~8 times，and the accumulation rate slows down when 15 times. Under the action of stress，the total energy absorbed by rock increases with the increase of strain，and the accumulation of dissipated energy is mainly concentrated in the failure stage of rock. Energy dissipation leads to damage development，and the trend of damage variable and dissipated energy is consistent.

Abstract:Drainage is one of the important anti-liquefaction functions of stone column，but there are few applications of anti-liquefaction based on drainage function in domestic engineering industry，and theoretical research and engineering experience are insufficient. This paper reviews the development history of anti-liquefaction based on drainage theory，summarizes the key points of different scholars’ anti-liquefaction based on drainage theory，and points out that the unfavorable well resistance must be considered in the methods of anti-liquefaction based on drainage. A port project in a high-seismicity area has successfully solved the liquefaction by using stone columns as their drainage function. The design program and calculation method of stone column in this project are introduced in detail. The method for determining the particle size gradation of stone column materials is summarized. The advantages and disadvantages of different stone column processes are compared，and the quality inspection methods for stone column of anti-liquefaction based on drainage theory are proposed.

Abstract:The silting dense silt distributed in Binzhou Port has low water content and large SPT（N），and is hard and difficult to dig，which brings great trouble to the dredging construction，especially challenges to the digging of trailing suction hopper dredgers，and affects the construction efficiency. In order to study the cutting mechanism of dense silt，the cutting experiment of dense silt has been carried out. Under the conditions of different cutting angles，different cutting depths and different cutting speeds，single draghead tooth and three draghead teeth underwater cutting experiments are carried out for three kinds of dense silt with water content，and the cutting experiments under high-pressure flushing are been carried out. During the experiment，the cutting force is monitored by the cutting force sensor arranged on the cutting tool. Through the cutting experiment of dense silt，the damage characteristics of dense silt are obtained，and the cutting characteristics of dense silt are summarized. According to the experimental data，the empirical formula for calculating the cutting resistance of dense silt rake is established.

Abstract:The foundation contains profound extremely dense backfill sand layer and extremely hard silt soil layer in a port project of Singapore，the large HZM/AZ combined steel sheet pile driving is one of construction difficulties in the project. We study the construction characteristics of the combined steel sheet pile，and find that reducing the interlock friction is the key for AZ auxiliary pile driving. We draw up the HZM pile construction precision control standards，and adopt construction sequence of driving auxiliary pile after main pile and construction measures of soil loosen at the middle interlock position，adopt the technology of installation by vibration hammer first then driving to final level by impact hammer for the large HZM pile driving，and optimize the guide frame design. The results show that the deviation and elevation of all pile tops meet the design requirements，and no tearing or disengagement of interlock is found.

Abstract:When the draghead excavates hard clay，the cutting resistance of the teeth is large，and the load of the main engine that needs to be matched is also increased correspondingly，which reduces the engineering economy. In order to analyze the value and change trend of the cutting resistance of the teeth in the cutting process of hard clay，and optimize the design and use of the draghead，we calculate the cutting resistance of teeth under multiple working conditions on the hard clay with a certain water content and standard penetration number，and calculate the length and width of soil damage during cutting by the calculation model. The results show that the horizontal cutting resistance of hard clay is greatly affected by the cutting depth，cutting angle and cutting width，and less affected by the cutting speed；when cutting hard clay，different types of teeth must be selected according to the actual working conditions. The cutting theoretical calculation model can be used for draghead design and construction process parameter optimization，which provides theoretical reference for the improvement of ship construction efficiency.

Abstract:Riprapping，tamping and leveling of subgrade bed are important construction procedures in waterway regulation project. With the rapid development of water transport economy in recent years，the poor construction conditions due to deep water with high velocity puts forward higher technical requirements for the construction technology of inland waterway regulation. During vibration compaction and leveling in the south channel regulation project of the Yangtze River Estuary，we adopt the vibration tamping and leveling integration technology：chute filling solves the shortcomings of traditional riprapping，such as large dispersion and high loss rate，vibration tamping and leveling technology improves the flatness of the foundation bed，the application of integrated ship realizes the function of continuous dumping，filling and tamping，which reduces the time waste of process conversion and improves the overall construction efficiency. The vibration tamping and leveling integration technology can be applied to offshore deepwater operation and provide reference for deepwater channel regulation construction.

Abstract:To meet the strict environmental requirements of a reclamation project in Hongkong，we transformed the common cutter suction dredger and put forward a construction technology of filling sandy soil by cutter suction dredger with sand bucket device. Given the problems such as low construction efficiency，sand filling leakage and sand bucket plugging，and based on cutter suction dredger with sand bucket device with nominal capacity 2，000~3，000 m3/h，we have adopted the methods of experiment analogy and field data collection and demonstration，and have put forward key points of efficiency control，environmental protection measures and the idea of grid reconstruction. We have figured out the optimal working conditions of the dredger under different sand conditions. The results show that the average efficiency of mechanical sand can reach more than 800 m3/h，and the average efficiency of sea sand can reach more than 1，500 m3/h. At the same time，the cost is reduced and the environment is protected.

Abstract:The D-160 diesel hammer is used for PHC pile sinking the first time in the Indonesian Banten Fengyi Industrial Park Port Project，and 9 PHC piles are selected for test pile sinking at typical positions in the sand layer. It wais found that the length of the pile shoe has a significant effect on the PHC pipe pile passing through the sand layer. The longer the pile shoe，the less the number of hammer strokes required to penetrate the sand layer，and the total number of hammer strokes will also be significantly reduced. When the pile shoe enters the sand layer，the penetration degree will decrease sharply. The main factor affecting the penetration degree is the larger end resistance. This process continues until the pile shoe penetrates the sand layer.