Abstract:In order to compare the difference of hydrodynamic characteristics between the caisson-type and comb-type breakwater，a numerical model of wave and the above two structures interaction is established based on OpenFOAM to analyze the reflection coefficients，wave pressure，and flow field distribution characteristics in different periods. The results show that：1）The reflection coefficient of the caisson-type breakwater is larger than the comb-type breakwater with the increase of relative width of the breakwater. 2）The differences in wave pressure at different measuring points are significant，and the wave pressure at the back plate of the comb-type breakwater is significantly higher than the wave pressure at the corresponding position on the headwind surface of the caisson-type breakwater.3）The water velocity in the comb cavity of the comb-type breakwater is significantly higher than that in the front of the caisson-type breakwater. 4）It is recommended to choose comb-type breakwater in the actual project.

Abstract:Relying on the actual project，we carry out the physical model test on the wave-eliminating characteristics of the permeable dike with baffle pile foundation，optimize the dike structure，and apply the previous research results. The results show that for breakwaters that are greatly affected by waves，the transmission coefficient behind the dike is related to the waves over the top of the dike and the seepage of the waves at the bottom of the dike，and it is necessary to consider the factor of waves over the top of the dike in the calculation. When optimizing the design of empty dikes，the wave-eliminating characteristics can be enhanced by increasing the water penetration depth of the wave breaker or increase the elevation of the top of the dike or adjusting both at the same time. It is recommended to use Wiegel formula to estimate the wave transmission coefficient of permeable dike with single-baffle pile foundation. Each formula has its own applicable conditions and the targeted structure is relatively simple，there are errors when it is applied to actual projects，and it is necessary to analyze the environmental characteristics and structural design characteristics of different projects，and reasonably select formulas for calculation.

Abstract:Regarding to the calculation for stable mass of bottom protection stone under current attack，a large amount of research has been carried out in the domestic and overseas，and a variety of calculation theories have been summarized and put forward，with different calculation methods given in different national codes. Due to different research conditions and backgrounds，different calculation results are often obtained by different calculation methods，which bring more inconvenience to engineers. In view of the above problems，we sort out the calculation methods given in Chinese and common international codes，make comparative analysis based on a project，and summarize the differences and applicable conditions in different methods. The results show that water depth is a sensitive factor affecting the mass of bottom protection stone，which should be significantly considered in the selection of calculation method. American code has better applicability due to more comprehensive in consideration of influencing factors，however，in the strong turbulent water flow condition，the Pilarczyk method and Escaramei & May method of the international general manual are recommended for comparison and comprehensive evaluation to determine the mass of bottom protection stone.

Abstract:To make the floating breakwater have the function of power generation on the basis of wave dissipation，we propose a new structural form，i.e.，oscillating water column（OWC）perforated floating breakwater. We numerically study the wave dissipation performance of the floating breakwater under the action of regular waves and analyze the effects of the spacing，opening width，anchoring mode，incident angle and other factors of the floating breakwater. The results show the followings. 1）Under three wave heights and different periodic wave conditions，the wave dissipation performance of OWC perforated floating breakwater is better than that of the ordinary double floating breakwater. 2）The wider the floating breakwater spacing and OWC opening width，the better the wave dissipation effect. 3）The wave dissipation performance of floating breakwater without anchor chain dragging is slightly better than that with anchor chain dragging，and the wave dissipation effect under normal incidence is better than that under oblique incidence.

Abstract:The mud has high resistance in pipeline transportation，which results in high energy consumption and thus severely restricts the efficiency of dredging production. This paper applies the vibration loading fluidization technology of sediment rheology to the research on the drag reduction of mud pipeline transportation and investigates the effect of vibration rheology on drag reduction in the pipeline system. The results show that the drag reduction effect increases significantly and then tends to be stable with the increase in the vibration frequency and is enhanced with the increase in the volume concentration but at a gradually decreased rate. The increase in the conveying flow rate weakens the drag reduction effect until making it level off. For the mud sample tested in this paper，there is an optimal vibration frequency，40 Hz，at which the system has reached the best state of drag reduction benefits. In a pipeline with an inner diameter of 100 mm，the resistance loss can be reduced by more than 20% for sediment at the Fengxian Beach with a median particle size of 31 μm when the mud volume concentration is 29.94%，the pipeline transportation velocity 0.9 m/s and the micro-amplitude mechanical vibration frequency 100 Hz. Finally，this paper proposes the calculation model for the drag reduction of the mud pipeline transportation by vibration rheology.

Abstract:To address the low efficiency in checking the elevation of the control point，this paper studies the principles and data processing methods of the Beidou ground-based augmentation system and the high-resolution EGM2008 gravity field model（1′ × 1′）. By integrating the above two technologies，this paper puts forward a specific process and an operation method for quickly obtaining the elevation of the point to be determined and verifies the method through engineering examples. The results show that the error is less than 5 cm regarding the external coincidence accuracy obtained by this method. It can effectively identify the availability of existing results and distinguish the type of an elevation system. The results of the proposed method are accurate and reliable，and the operation is convenient and efficient. In addition，the method can reduce the costs，which has a reference value for similar port and waterway engineering.

Abstract:Overseas seismic design codes of wharfs commonly utilize earthquake-induced permanent deformation for the stability analysis of bank slope，and the deformation is determined by empirical formula or charts，which are established based on the Newmark’s sliding block method. However，there is no similar method in the seismic design codes for water transport engineering in China. Thus，the Newmark’s sliding block method is conducted to analyze 3，600 artificial seismic waves which fitting the response spectrum of the seismic design code for water transport engineering in China，and the statistical characteristics and distribution of block displacements are determined. Therefore，a simple analysis method is proposed，and the implementation process of the method is illustrated by a case of a real wharf bank slope. The results show that：1）The mean value of permanent deformation determined based on the Newmark’s sliding block method is a function of yield acceleration of the bank slope. The coefficient of variation is a function of the ratio of yield acceleration to the peak ground acceleration. The permanent deformation obeys a logarithmic normal distribution.2）The stability of the bank slope can be analyzed by directly comparing the mean permanent deformation calculated by proposed equation with the specified limited value，or by calculating the deformation value under a certain guarantee rate to conduct the corresponding stability analysis.

Abstract:PHC pipe piles have strong adaptability to engineering geology，and are widely used in port engineering. When it takes hard clay layer，dense sand layer or bedrock as the bearing layer，and the above soil layers fluctuate violently and irregularly，the pile sinking quality is very difficult to control，which is easy to cause the problem of sinking abnormal piles such as high or low. For sinking low pile，in order to ensure the project progress and save investment cost，pile connection measures are generally given priority. Aiming at the connection scheme of sinking low pile，this paper focuses on a new type of pile connection structure of PHC pipe pile，that is，according to the actual elevation deviation of pile top，the pile core channel steel is used to strengthen or combine the pile top with cylindrical concrete，so as to meet the requirements of rigid connection between pile foundation and superstructure. The practice results show that the new pile connection structure is suitable for sinking low piles with different slopes，which can effectively avoid the disadvantages of additional structural weight，increased construction difficulty and poor overall appearance quality caused by conventional pile connection by adjusting the scale of superstructure，and can provide reference for similar projects.

Abstract:According to the requirements of the Code of Design for Breakwater and Revetment，for the sloping dikes on the scoured foundation，large stones of the underwater prisms should be thrown on small stones with a thickness of not less than 0.5 m or the geotextile soft mattress. For sandy coasts with partially exposed rocks，the geotextile soft mattress is easily punctured in part and cannot be used，and it is also difficult to meet the design working life of up to 50 a. Furthermore，there is no strict international standard on the filter calculation of pre-laid gravels，and no strict theoretical basis for gravel thickness. In view of these problems，combined with the filter design principles from China and foreign countries，this paper elaborates the filter design of the sloping dike bottom by adopting the strict filter principle and geometrically stable filter principle，which better makes up for the design deficiencies in the international standard.

Abstract:To improve the operation efficiency of the horizontal transportation system of automated container terminals and promote the development of the container collecting and dispatching system，we research the intelligent horizontal transportation mode and system design considering the requirements of container terminals for automated and intelligent construction. After analyzing the production operation process of automated container terminals，we formulate the overall operation mechanism of the terminals and design the functions and operation modes of the horizontal transportation system. Moreover，we design the working mechanism and process of the horizontal transportation system from multiple aspects such as operation scheduling，path planning，traffic control，and charging management. Furthermore，we present the decision-making method of intelligent transportation of automated container terminals and adopt the control strategy of combining the overall planning and local guidance of transportation operation. This research can provide reference for the construction of automated container terminals and the development of intelligent horizontal transportation systems.

Abstract:Due to the serious scouring of water flow in the front area of Xinhai Wharf，the underwater mud surface elevation has been lower than the condition at the time of completion. Thus，it is necessary to reassess the structural safety of the wharf and the stability of the bank slope. The scour depth of the pile foundation is obtained by monitoring the topography of the underwater bank slope. According to the requirements of relevant specifications，the bearing capacity of the upper structure of the wharf，the bearing capacity of the pile foundation and the stability of the bank slope shall be rechecked and calculated. The results show that all indicators of structural safety meet the requirements of the specifications. However，the tensile stress of the pile body is close to the limit value. If the scour depth further increases，it will threaten the structural safety of the wharf. After comprehensive consideration，the scheme of the soft mattress of interlocking blocks and riprap is adopted to protect the bank slope.

Abstract:Aiming at the problem that seasonal runoff has a great impact on the hydrodynamic conditions in the estuary area，the variation of water and sediment characteristics in flood and dry seasons of Wugang Wharf，Taicang in the Yangtze River is studied.We compare the test data of tide level，tidal current，sediment concentration，suspended load and sediment in flood and dry seasons of Wugang Wharf，Taicang from 2018 to 2019 by prototype observation method，and analyze the changes of water and sediment characteristics in flood and dry seasons in the project area.The results show that the change of tidal level in the project area is obviously affected by runoff；The project area is a typical reciprocating flow，and the fluctuation trend is basically the same in flood and dry seasons；During the hydrological test，the sediment concentration in dry season is slightly lower than that in flood season，and the difference range is 5.88%～25.67%；The median particle size of suspended load in flood and dry seasons is basically the same；The bottom material is mainly composed of cohesive silt，cohesive soil and fine sand.

Abstract:In view of the ineffective operation of automated equipment in container terminals，we study the rational layout of terminals. Analyzing the current development situation of terminal automation technology and the new type of automated container terminals under construction in Tianjin Port，we consider the loading and unloading of ships，horizontal transportation，as well as type selection of yard operation equipment comprehensively from aspects such as the terminal front and yard layout，and propose a general layout plan for automated terminals，in which the container yard is arranged horizontally to the terminal front. To improve the automation level of terminal operation，we introduce several advanced technologies such as unmanned driving，artificial intelligence，and big data，and use artificial intelligent robots of transportation （ART）to replace the traditional transportation equipment. The result may serve as a reference for the construction and development of automated container terminals in China.

Abstract:For the reconstruction or new construction projects of bulk cargo yards，the environmental protection requirements of conventional open bulk cargo yards are becoming more and more stringent，and thus the dust-proof design of yards must be considered. However，the dust suppression effect of the conventional design scheme of adding dust suppression nets to open yards is poor. Therefore，the design schemes of different closed yards are analyzed，such as vertical silos，circular stockyards，and strip yards，and multiple factors are considered in the analysis，such as the material adaptability，handling efficiency of process systems，storage capacity，and unit storage costs. It is concluded that the closed strip yard is an economical and reasonable selection for bulk storage yards. Furthermore，in view of the requirements such as handling processes，structure design，and fire safety，it is determined that the closed strip shed with a low column and a large span is an optimal solution that can be recommended for a bulk cargo yard.

Abstract:It is still necessary to study whether fender should be installed between fender pile and wharf and the calculation method of fender pile with fender in front of berth pile. In this paper，Abaqus finite element analysis software is used to analyze the steel fender pile with fender on both sides. It is believed that the fender pile can be analyzed by p-y curve method，and the inner fender is analyzed by nonlinear spring. The optimal design of the fender pile is carried out by engineering examples combined with an engineering example. The results show that the inner fender is helpful to reduce the internal force of fender pile. The steel tube pile is made of high strength steel，and the local strengthening of steel tube pile can significantly improve the performance of fender pile.

Abstract:In the process of flexible mattress sinking in waterway improvement engineering，the precise control of mattress location is an important factor that affects the success and quality of construction. Currently，the selection of sinking parameters mostly depends on empirical judgment because of the lack of theoretical and experimental research. Through the generalized flume experiment，the influence of different parameters on drift distance of mattress head in the process of downstream sinking was studied，and the sensitivity difference of each parameter was quantified. Based on the theory of multivariate nonlinear regression，a prediction model of the drift distance of mattress head under the effect of multiple factors was established，and its prediction accuracy was statistically analyzed by using correlation coefficient，mean absolute percentage error，etc. The experimental results show that the drift distance decreases with the increase of beam weight and rope length，while increases with the increase of water depth and velocity. The sensitivity order of each parameter from largest to smallest is velocity，relative rope length，water depth and beam weight. The study results can provide a scientific basis for the construction of flexible mattress sinking.

Abstract:Baishiyao hub locates on the Beijiang River main stream，25 km upstream from Yingde city. It is the third cascade of the Beijiang River. To improve the passage capacity of the ship lock，the length of the lock chamber of the Baishiyao first line ship lock is extended from 140 m to 220 m. The effective scale of first-line ship lock design is 220 m×23 m×4.5 m（length×width×doorsill water depth）. This paper studies the flow condition of the entrance gate of the downstream approach channel by establishing a 1:100 scale physical model. Through the overall hydraulic model test，the paper puts forward the improvement measures of the navigation condition in the entrance area of the downstream approach channel. The study shows that measures such as the excavation of Sanbanzhou and the addition of linear dikes are effective to improve the navigation condition at the entrance of the downstream approach channel.

Abstract:Qingyuan second-line ship lock has a large plane scale and adopts a new type of energy dissipater with a combination of sill and beam. In order to understand the hydraulic characteristics when ship lock filling and discharging，berthing conditions and the interaction between double line ship locks，propose solutions to ensure the safe and efficient operation of locks，the hydraulic prototype observation and the full-scale ship test were carried out，and the hydraulic characteristics and other operation parameters of Qingyuan second-line lock were observed in detail，and various indexes were analyzed. The test results show that under the existing operation mode，the gate and the valve operate well，and all hydraulic indexes meet the design requirements of the specifications. However，due to the side-by-side arrangement of the first- and second-line ship locks on the same bank，the completion of the second-line lock leads to the change of the boundary conditions of the first-line lock. The upstream piers of the first-line lock are close to the inlet of the second-line ship lock. During the second-line lock filling，it will have a certain impact on the flow conditions of the berthing section of the first-line lock.Therefore，the joint dispatching of the first- and second-line locks should be strengthened.

Abstract:In order to study the influence of anti-collision devices on the navigation of bridges in mountainous rivers，a two-dimensional physical model test was carried out to investigate the influence of anti-collision devices on the navigation of ships in the presence of intersection angles between bridges and water currents by analyzing ship navigation parameters such as the bow angle θ and drift angle β using the principle of deviation from the course of a moving ship. By setting up multiple routes，we explore the safe distance between a ship and a bridge pier when sailing. The experimental results show that the impact of anti-collision devices on navigation of river piers in mountainous areas is much greater than that of bare piers，and the impact of anti-collision devices on navigation of ships with pointed bow is greater than that with rounded bow. The larger the angle of intersection between the bridge pier or anti-collision device and current，the larger the deflection range of ship，especially when the angle is 0°-10°，the influence is the largest. Several sets of route navigation tests show that the closer the route is to the bridge pier，the greater the impact on the ship，with this impact peaking when the distance between the route and the pier reaches 3W. The results may serve as reference for the study of safe navigation of mountain river bridges and the research and development of anti-collision devices.

Abstract:To the east of the new Qingfeng Junction Locks on the Cao’e River，the original flap gate was dismantled and converted into a 10-hole sluice gate，with the Qingfeng Junction Power Station to the east of the sluice gate. The narrowing of the river channel downstream of the locks leads to adverse effects on the flow regime of the approach channel downstream of the locks due to the discharge of water from the spillway and the power station. Thus an overall physical model test was used to study the effect of different flow rates and spillway opening methods on the downstream approach channel of the locks. The test shows that when the river’s flow discharge is greater than 850 m3/s，no matter what kind of opening method for the sluice gate is used，the flow rate in the lock’s downstream approach channel cannot meet the specification requirements；when the river’s flow discharge is less than 850 m3/s，the way of using all the gates to open evenly is conducive to weakening the downstream backflow intensity of the sluice gate，and the channel’s flow rate meet the specification requirements.

Abstract:There are complex flow patterns in the entrance area of the upstream approach channel of ship locks in the curved reach，such as reflux and oblique flow. The hydraulic characteristics of navigable flow in the upstream approach channel and the entrance area of ship locks are studied by changing the scheduling method of a check gate with the combination of physical model tests and numerical simulations. The results show that with the upstream inflow of 1 000 m3/s，the maximum lateral flow velocity and reflux velocity upon opening the fourth hole in the middle by the check gate are greatly smaller than those upon opening the eighth hole on the left；with the upstream inflow of 1 500 m3/s，the maximum lateral flow velocity and reflux velocity upon opening the fourth hole in the middle are greater than those upon opening the eighth hole on the left. When the flow rate is consistent，the flow velocity distribution of the measuring points on the section varies greatly. Controlling the scheduling method of a check gate can effectively weaken the reflux and oblique flow effect and ensure navigation safety.

Abstract:The Jili junction of the southern branch of Ganjiang River is located in the channel with an S-shaped sharp bend and complex river regime topography，and thus the flow conditions in the entrance area of the approach channel and the connecting section are poor. Therefore，this paper studies its navigable flow conditions by the overall hydraulic physical model of 1：100. The results reveal that 1）the upstream flow conditions of the junction are complicated. The requirement of maintaining the lateral flow velocity within 0.3 m/s can be met by engineering measures including adjusting the intersection angle between the upstream route and the main flow to 31.08°，regulating the elevation of the sub-embankment on the beach to 17 m，retreating the earth embankment by 30 m，and joining the embankment. 2）In the downstream entrance area and the connecting section of the junction，the downstream beach cutting angle can be adjusted to 10° to make each flow velocity indicator satisfy the requirements of the code.

Abstract:The stage of the Puyang River waterway is not only influenced by the runoff peak discharge in the upstream regions，but also supported by the tidal water in the downstream regions. Thus，the reasons for the high stage are complex. It is very urgent to demonstrate the navigable stage of the waterway for strengthening the management of navigation-related structures such as navigation channels and bridges and further enhancing the capacity of the waterway. In the Navigation Standard of Inland Waterway，the designed highest navigable stage is deduced by the design flow method with the stages in flood recurrence periods at different levels. In light of this，we establish a two-dimensional hydrodynamic mathematical model to calculate the designed highest navigable stage for 5-year，3-year and 2-year flood recurrence periods. Taking into account the river channel conditions，channel grades，flow conditions and bridge’s navigation clearance，we recommend the stage of Puyang River in the 2-year flood recurrence period as the highest designed navigable stage by referring to the data of designed stages upstream and downstream，characteristic stage under flood control and historical stage statistics.

Abstract:With the increasing demand for water transport in the Beijiang River and the expansion and upgrading of the waterway，it is planned to build a new third-line ship lock on the basis of the first-line and second-line ship locks of the Qingyuan Hub，and reserve space for the construction of fourth-line ship lock. Based on the construction scheme of the left bank of the third-line ship lock，a plane two-dimensional water flow mathematical model is established to study the navigable flow conditions and existing problems in the entrance area of the approach channel and the connecting section. The results show that：1）In working conditions 2 to 4（Q≥5 000 m3/s），the cross flow in the upstream gate area of the third-line ship lock is significant，which is greater than 0.3 m/s. 2）The flow of the Dayan River in the lower reaches of the ship lock flows into the straight channel. In working condition 3，when the flow rate of the Dayan River is 1 510 m3/s，the cross flow of the connecting section at the confluence exceeds the standard and the navigation conditions are poor.3）After further optimization test of the ship lock scheme，measures such as adding diversion piers in the upstream mouth area，arranging diversion dams and diversion piers in the downstream Dayan River mouth，and widening the dredged Dayan River mouth can effectively improve the cross flow.

Abstract:In recent years，the number of overseas channel dredging projects has increased. Different calculation standards of the design of the channel bottom elevation brought different bidding costs or implementation costs in EPC projects due to different water depths in channel design. This article describes in detail the influence factors on the design of the channel bottom elevation in overseas channel projects，and makes a comparative analysis of the current European，American mainstream codes and Chinese codes in terms of consideration aspects，value-talking method and the advantages and disadvantages so as to summarize the relative merits and applicability of each code，and also propound advice and direction for Chinese code to “go globally”. According to the demonstrations of the two projects，it is recommended to conduct a comparative analysis through calculations under different codes in designing the channel bottom elevation. After the applicable mainstream code is selected with the design based on port information and conditions，the optimal demonstration should be conducted through the simulation test of ship manipulation.

Abstract:Through the method of combining theoretical calculation and experimental research，the reasons and the influencing factors for the looseness of the support bolts of the Three Gorges ship lift tumble gate opening and closing cylinders are discussed，and the countermeasures are put forward. The results show that：1）Under the action of alternating load，the tumble gate is opened and closed frequently. The looseness of the bolts is caused by both material looseness resulted from plastic deformation of each contact surface of bolted connection of the opening and closing cylinder under large load and structural looseness caused by micro slip of screw pair.2）With the increase of the number of reciprocating opening and closing of tumble gate，the looseness of the bolts gradually increased until they failed.3）Through measures such as regular inspection，ultrasonic bolt pre-tightening force detection，and re-tightening，the looseness of the support bolts of the tumble gate opening and closing cylinder can be effectively reduced.

Abstract:The project of high-piled wharf is usually large-scale，highly professional and various participants for construction，which leads to the independence and poor timeliness of construction information，and greatly affects the project schedule，resulting in waste of construction cost. In order to solve this problem，we propose an optimization algorithm of the construction schedule，and build a 4D construction management method combined with building information modeling（BIM）technology. We build the component library of the high-piled wharf’s Revit model，construct the corresponding 3D information visualization model of the high-piled wharf，establish the construction schedule optimization algorithm of high-pile wharf based on the quantum particle swarm optimization algorithmin line with the construction characteristics，organically integrate the optimization algorithm for construction schedule with the BIM construction model of the high-piled wharf，and use BIMFILM software to carry out the optimization of construction period information and the dynamic visual management throughout the entire construction process. The results show that this method not only realizes the visualization and information management of construction schedule optimization，but also the proposed dynamic optimization algorithm helps to accurately predict and simultaneously optimize the construction schedule，reduce the total construction cost，and improve the efficiency of wharf construction management，which has expanded the application way of BIM technology in the field of hydraulic engineering with practical significance.

Abstract:For the layout problem of ground locking stations considering the front and rear buffers，we propose a dynamic layout strategy of locking stations based on the traditional plan of fixed locking station layout，which can dynamically adjust the number and position of locking stations according to the size of ships to adapt to the operation requirements. On the basis of analyzing the process of unlocking containers in automated terminals，we use the software AnyLogic to build a simulation model for the dynamic layout of ground locking stations considering the front and rear buffers，and use the system operation efficiency，equipment occupancy rate，and buffer queue length as the measurement indicators to evaluate the actual performance of the dynamic layout strategy of locking stations. The results reveal that compared with the traditional fixed layout of locking stations，the dynamic layout of ground locking stations can balance the load of each lock station and the average queue length of buffers，and the system operation efficiency is increased by about 14.6%. The dynamic layout of lock stations can improve the overall utilization rate of locking stations and meet the requirements of loading and unloading ships and horizontal transportation operation.

Abstract:Considering the traffic congestion in automated container terminals and the construction project of an intelligent container terminal in section C of the Beijiang port area of Tianjin Port，a dynamic parking design of artificial intelligence robots of transportation（ART）in automated container terminals is proposed on the basis of the arrangement mode of alongshore side-loading/unloading. This design achieves the setting of the parking area by several setting modules，including the parking area，parking priority，parking quantity and rules，and multi-scene parking rule control，and ART can be controlled by the dynamic parking strategy to accomplish the parking tasks. The research indicates that the dynamic parking design scheme has a relatively complete parking control process，which provides a reference for automated container terminals to improve the traffic flow of ART.

Abstract:The selection of soil rupture surface is related to the calculation accuracy and engineering economy in the stability analysis of retaining structure，sometimes it also affects the engineering safety. Considering that the rupture surface of foundation soil may be located inside the sheet pile cellular when it overturns，we analyze its failure mode and calculation method，build a numerical model to analyze the location of soil rupture surface at the bottom of the sheet pile cellular based on an engineering example，propose the calculation assumption of“double rupture surfaces”of Hansen method in view of the inconsistency of the bottom elevation of adjacent cellular，give a specific calculation example，and propose two methods to improve the stability of soil failure surface inside the cellular. The results show that increasing the penetration depth of sheet piles and strengthening the soil in the passive area and inside the cellular can effectively improve the stability of sheet pile cellular along the internal failure surface.

Abstract:The Guiling Island wharf project in Shanwei City，Guangdong Province adopts clay-sand mixed soil foundation. The results of the undrained shear tests with different sand contents show that：1）The fractal dimension of mixed soil decreases rapidly with the increase of sand content. 2）The shear strength characteristics gradually change from hardening type to softening type. 3）The fractal dimension of 2.709 3（sand content of 50%）is the limit value for the obvious change of mechanical properties of clay sand mixed soil，and the mechanical properties of two sides show great differences. 4）The angle of internal friction increases and the cohesion decreases. Combined with the foundation bearing capacity of the empirical formula，the actual material and other factors to determine the sand content of 30%～40%. 12 monitoring points are selected to review the results.

Abstract:We select four commonly used domestic and foreign codes and reference for stone column design，i.e.，the codes of the Federal Highway Administration（U.S.），the common design reference in Europe，the Chinese codes Technical Code for Ground Treatment of Buildings and Code for Foundation Design on Port and Waterway Engineering，and conduct a comparative analysis from the aspects including the applicability of stone columns，the grading requirements of column material，and the design parameters of stone columns. In addition，this study compares the determination process of design parameters for foundation treatment of stone columns with the aforementioned codes and reference on the basis of the Tibar Port project in East Timor. The results reveal that regarding applicability analysis，the foreign code and reference provide quantitative grading analysis tables，while domestic codes only provide qualitative analysis. For the determination of column material grading，the foreign code and reference present typical grading curves，while domestic codes only introduce regulations in principle. For the column diameter and spacing determination，the foreign code and reference provide empirical relationship design diagrams，while domestic codes only give applicable range values.

Abstract:In order to reveal the creep mechanical properties of red sandstone under different water content conditions，we carry out triaxial compression creep tests under the control conditions of 0%，1.25%，3.16% and 5.38% water content，and analyze the creep test results to explore the strain characteristics，creep rate and long-term strength of red sandstone under different water bearing conditions. It is found that：1）Red sandstone shows three-stage creep behavior under the action of water and stress，and creep failure occurs in rocks with high water content under less loading levels；2）The creep strain of red sandstone is much larger than the instantaneous strain，and the action of water promotes the growth of instantaneous and creep strain；3）The increase of moisture content promotes the increase of initial and ultimate accelerated creep rate；4）The long-term strength of red sandstone under four water contents is 22.86，21.91，16.27 and 10.74 MPa respectively. The long-term strength decreases gradually with the increase of water content. The research results may serve as reference for the study of creep characteristics of red sandstone and the long-term stability analysis of port foundation.

Abstract:Coral sand is a special kind of geotechnical material widely distributed in countries participating in the Belt and Road Initiative. Due to its engineering characteristics of breakability，large deformation and high compressibility，the applicable technology and final reinforcement effect of the foundation treatment are different from those for the ordinary terrestrial sand to some extent. In an actual project，we carry out vibro-compaction tests to investigate the various technological parameters of filling the coral sand foundation. The results show that for the surface of coral sand，reverse insertion and vibration time increase can effectively improve the soil compactness between piles. Regarding the bottom medium-density coral sand layer，if the reinforcement effect needs to be further improved，the distance between vibro-compaction points should be reduced to less than or equal to 3 m. For the loose coral sand layer with high-content fine particles，the optimized process of reverse insertion and vibration time increase can effectively improve the soil compactness between piles，but further reducing the distance between vibro-compaction points on this basis cannot significantly improve the final reinforcement effect.

Abstract:The movement state and pipe resistance characteristics of broken rock in the discharge pipeline are quite different from other soil properties，and the resistance loss mechanism of rock transportation is complex. Therefore，there is a lack of universal calculation model for rock transportation in the field of dredging. We discuss the motion state of solid particles，the characteristics of resistance loss and the basic theory of resistance model，and analyze the characteristics and applicability of Durand classic resistance model. Based on the transportation data of “Tiankunhao” in Dayaowan，Dalian and a rock dredging project in Russia，we modify and calculate the Durand model，and obtain the modified value of Durand coefficient KD. The results show that the accuracy of pipe resistance calculation is greatly improved，so that the application scope of the model is extended to the rock with particle size less than 100 mm.

Abstract:In the channel expansion project of a port in Guangxi，the cutter teeth of the heavy-duty cutter suction dredger “Tiankun” are worn out and fractured during the dredging operation of typical weathered sandstone，which affects the efficiency of construction. On the basis of analyzing the tensile strength and mineral composition characteristic indexes of the dredged weathered sandstone，we deduce the empirical relationship formula between the abrasiveness index of the sandstone in Qinzhou of Guangxi and the consumption of cutter teeth by the theory of dredged rock abrasiveness. This formula is used to predict the consumption of cutter teeth for digging weathered rocks by a heavy-duty cutter suction dredger. The research results reveal that 1）the integrity of the moderately weathered sandstone rock mass is good，with the uniaxial saturated compressive strength of 9-41 MPa and the geotechnical engineering property grading of the dredging as Level 12-13. In the dredging of the moderately weathered sandstone rock mass，the problems of abrasion and fractures of the cutter arm and teeth are prominent，and the moderately weathered sandstone is the key soil quality that affects dredging efficiency. 2）The improved theory of Schimazek’s F value is innovatively introduced to evaluate the abrasiveness of rock materials by comprehensively considering mineral compositions，mineral content，mineral hardness，rock particle size，and saturated tensile strength of rock. 3）On the basis of the theory of rock abrasiveness and construction parameters of dredging，the formula between the cutter teeth consumption of “Tiankun” per 10，000 cubic meters and the improved Schimazek’s F value is derived. 4）The absolute relative deviation between the calculated value and the measured value of the cutter tooth consumption of “Tiankun” per 10，000 cubic meters is less than 17.3%，which indicates good reliability and can provide technical support for rock dredging.

Abstract:To solve the problem of mouth bars at the entrance of Chaohu waterway，this paper studies the design scheme of silt geotextile tube embankment with a field test，calculation check and benefit analysis under the on-site engineering construction conditions of the entrance. The field filling test results indicate that the 2.8 m ×1.6 m×0.6 m flat geotube scheme is better in dehydration efficiency and stacking stability. The calculation results show that the overall stability of the jetty design scheme has sufficient safety reserves. The maximum settlement（about 88 mm）occurs at the embankment core，and the settlement difference between the core and the toe of the embankment is about 15 mm. In addition，the design scheme meets the requirements of anti-slip stability between geotextile tubes under the design wave load. The benefit analysis manifests that the silt geotextile tube embankment scheme can save more than 20% of the cost，and it has great environmental and social benefits.

Abstract:To address the difficult construction of tall cast-in-place underwater concrete formwork，the low efficiency of underwater formwork disassembly and high safety risk of frequent hoisting，this paper studies the underwater connection，dismantling and hoisting technology of large formwork. T-shaped bolts and three-stage clamping strips are designed for the underwater connection of independent piers，and the underwater mold removal time is shortened to 3-4 hours. A multi-functional combined sling is designed，and the positive and negative rotary connectors are used to realize the release and overall lifting of the underwater formwork top，which improves the construction efficiency，reduces the construction cost and ensures the construction safety. It has reference significance for similar underwater large-scale concrete formwork projects.

Abstract:A hydraulic project in Tanzania is a reconstruction and expansion project. The original pier of the transfer section of berths 3#-4# is a gravity structure and a high-piled，reverse-beam and large-slab structure，which was built in the 1960s. The original gravity structure is retained in the reconstruction and expansion design. The cantilever high-pile cap structure，the high-pile beam plate structure，and the high-pile cap structure are used for mixed structural design to minimize the load acting on the original gravity structure and ensure the stability of the structure. The farthest part of the longitudinal beam on the land side is constructed with miscellaneous filling bottom form，which can reduce the consumption of the support system. The concrete surface layer of the high pile，reverse beam and large slab structure is reserved as the construction platform of the cast-in-place pile steel tube，which can shorten the construction period of the cast-in-place pile.