Abstract:After the implementation of the second phase of the 12.5 m-deep channel regulation project in the Lower stretch of the Yangtze River downstream of Nanjing,the effect of channel regulation in the Luochengzhou passage is remarkable with ship traffic increasing and large-scale trend of vessels passing being significant.The navigation environments in the Luochengzhou passage are complex as affected by the sharp curve and high flow velocity at Sima bend,the coexistence of -10.5 m and -12.5 m deep channels,the mixing downstream sailing of large-scale and small-scale vessels and other factors.In the flood season of 2017,there were several cases of large-scale ship grounding accidents owing to sailing out of the -12.5 m deep channel by mistake while sailing upstream.According to the analyses of riverbed evolution,flow field and navigation behavior,this paper proposes the following optimization measures to be taken in the Luochengzhou passage:to realign the layout of the main channel to the left,add an additional recommended downstream route to realize the separate sailing of large-scale and small-scale vessels,apply virtual aids to navigation,and optimize the existing waterway regulation projects,to further establish a safe and efficient navigational pattern.

Abstract:Taking 9 ports above designated size below Nanjing of the Yangtze River as beneficiaries of the 12.5 m deepwater navigation channel,this paper analyzes and evaluates the impact and practical benefits of the 12.5 m deepwater navigation channel on ports along the Yangtze River below Nanjing by the data of port throughput from 2009 to 2017.The results show that the total cargo throughput of ports along the Yangtze River increases steadily as a whole since the opening of the 12.5 m deepwater navigation channel,and the annual growth rate of cargo throughput increases 8% when the deepwater navigation channel first opens to Nanjing in 2016.The total cargo throughput of the major ports below Nanjing in 2017 (2.425 billion tons) is 1.8 times that of the deepwater navigation channel before its opening in 2009.The increasing extent of the container throughput is the most obvious after the opening of the deepwater navigation channel,but the proportion of bulk cargo throughput has a slight decline compared with that of before opening.The economic benefit of ports along the Yangtze River below Nanjing increases steadily for 8 years of opening.The economic benefit of ports along the Yangtze River generated in 2017 (1.34 billion yuan) is nearly 60% higher than that in 2010.With the continuous improvement of conditions for channel,ships and ports or wharfs along the Yangtze River in the future,the comprehensive benefits of the 12.5 m deepwater navigation channel below Nanjing of the Yangtze River will be further highlighted.

Abstract:In order to study the distribution characteristics of wave field under different layouts of breakwaters in the engineering sea area of Yanwoshan,we carry out a numerical simulation of wave field near engineering area by using wave action conservation equation and Boussinesq equation to establish wave mathematical models in large and small scale,and analyze the wave parameters of wave observation station near breakwater.We change length and axis angle of breakwater based on the first plan so as to compare the shielding effect of waves under different layouts of breakwaters.The results show that when variation characteristics of wave field,wave parameters of wave observation station and effective shielding area are overall considered,the second plan is the suitable choice,the axis of the breakwater is intersected at the intersection of two dikes,the center is rotated 8°counterclockwise,and the embankment is extended 100 m to the east side.

Abstract:The construction of monitoring and control network of offshore artificial island can be established by means of offshore measurement platform.We carry out a special study on the problem that the measuring platform of offshore rigid structure is susceptible to external factors such as temperature,humidity,pressure,wind force,tide and so on,which has a great influence on the precision of the monitoring and control network.Based on the monitoring project of west artificial island project of Shenzhen-Zhongshan Bridge,we propose a transference method of height difference through reasonable controlling technical indexes,verify the feasibility of the method by the analysis of precision,realize the establishment of construction monitoring and control network which meets second-class technical requirements,and give several measures to improve the precision.It can provide references for the construction monitoring of offshore artificial island.

Abstract:Studying on the wave force of the circular lamp pile structure of the sloping breakwater is great significance to the design and stability of the breakwater.Based on the physical model tests in a wave flume,we analyze the time variation of wave pressure at different positions,the distribution of wave pressure on the structure surface,and the synchronous wave pressure distribution characteristics at each measuring point when the horizontal force or vertical force is the maximum.We also compare the experimental results of the wave force with the results calculated by the standard about the vertical chest wall.The results show that the wave pressure in the non-shielded part is mainly the combination of the impact pressure and the gradually varying pressure.The wave pressure in the shielded part shows the slowly varying pressure.From the top of the lighthouse to the bottom of the lamp pile foundation,the wave pressure increases first and then decreases with the relative height decreasing.When the water level exceeds a certain height of the structure and the structure is protected by block,the wave pressure at the low part is approximately uniformly distributed,but without protection,the maximum wave pressure occurs at the maximum of horizontal force.When it is partly protected,the wave horizontal force of the lamp pile structure is smaller than that under no protection,but larger than that with a full protection.Based on code of hydrology for sea harbor,the correction coefficient and fitting formula are obtained，which can calculate the wave horizontal force of this structural type on sloping breakwater.

Abstract:In view of technical requirements of concrete material for rapid construction under marine environment,we prepare the high durability concrete for rapid construction by using sulphoaluminate cement,proper slag powder and silica fume,and adding special high performance water reducer and retarder,and research its performance by the experiment.The results show that the high durability concrete for rapid construction has good workability,low slump loss and good chloride corrosion resistance,and satisfies the requirement of pumping construction.It can provide an effective technical way for rapid construction in marine environment.

Abstract:The effect of different berth lengths on the mooring of 172,000 m3 LNG ship is studied by the 1:60 overall model test.The movement and cable tension of the ship under the combined action of wind,wave and flow are analyzed.The research shows that under the conditions of transverse wave,transverse wind and falling current,the length of berth is shortened,and the bow and stern cable force shares part of the transverse cable force,which is beneficial to the balanced bow and stern cable and transverse cable force,and the maximum cable forces become smaller;the change of berth length has little effect on mooring force under the conditions of downwave,downwind and falling current;under the condition of oblique wave,transverse wind and falling current,the ship is affected by oblique wave,and the wave force is distributed in both directions,and the force of spring cable is basically the same as that of transverse cable or bow and stern cable;when the wind is following,the spring force will be greater than the transverse force and the bow and stern force.The study recommends a suitable berth length for the Tianjin LNG project,which can provide reference for the design of the wharf.

Abstract:Container trucks are main energy-consuming equipment in port area of container terminals.The carbon emission from container trucks is especially serious when two very large container ships are stevedoring simultaneously.Therefore,we build a micro-simulation model of container terminal operations by agent-based simulation and microscopic traffic simulation to explore the modes of container trucks scheduling on ship turnaround time at port and carbon emission by trucks in this case.According to the characteristics of truck scheduling mode,we build a micro-simulation model of container terminal operations by agent-based simulation technology and make a quantitative analysis to explore the effect of container truck scheduling modes (including tandem model of loading after unloading for each ship,dual-cycling model of loading and unloading between two ships,and dual-cycling mode of loading and unloading within same bay) and number of trucks on ship turnaround time at port and carbon emission.The example shows that the dual cycling mode can effectively reduce the carbon emission while ensuring the handling efficiency,and the number of container truck only affects the carbon emission generated by idling truck.

Abstract:Taking the pile foundation of second-phase project of Guoyuan Port as the prototype,we carry out the low-cycle repeated loading test of concrete-filled steel tubular column,and analyze the reinforcement rate and concrete strength of different core concrete based on ABAQUS finite element software.The results show that the steel tube of concrete-filled steel tubular column is prone to buckling and even bulges at the bottom of the column.As the thickness of the steel tube increases,the plastic deformation capacity of the concrete-filled steel tube structure is enhanced,which has the advantages of high bearing capacity and good ductility.The plastic deformation and energy dissipation of CFST column model are enhanced by the increase of reinforcement ratio.However,the increase of concrete strength has limited effect on the plastic deformation and energy dissipation of concrete-filled steel tubular column.

Abstract:In view of the detection difficulties of caisson joints of the gravity wharf,underwater robot,multi-beam and 3D sonar scanning technology are used to detect.Test data shows that the effect of the underwater robot is intuitive and accurate;the multi-beam system has certain recognition ability for caisson joints,but has poor resolution for the smaller-width and longer-distance joints;the scanning of 3D scanning sonar detection is highly accurate,but the scanning range is small and the scanning efficiency is low.Based on the principle of testing,we analyze the reasons of the advantages and disadvantages of various methods and designs the 3D sonar measurement bracket independently according to the testing requirements,realize the measurement of any depth of the caisson joints,and obtain a good test effect.It may serve as reference for selection of the detection method of caisson joints.

Abstract:Aiming at the damage problem of breakwater structure in open sea area caused by wind and wave,the reason of damage is analyzed and the suitable repairing and reinforcement scheme is selected.Based on the detailed data of wind,wave and current,especially considering the influence of several strong-super typhoons on the wind and wave in the engineering sea area in recent years,the main design parameters such as the top elevation of breakwater,the mass of protective face block and the cross-section structure pattern are determined by combining standard calculation with model test.At the same time,the layout of the breakwater is optimized from the point of view of the function of the breakwater and the berthing conditions in the harbor.Combining with the results of model test,this paper puts forward a more pertinent scheme of repairing and strengthening and optimizing layout,which has a certain reference significance for similar projects.

Abstract:Shear keys have been widely used in deep-sea engineering,but the mechanical mechanism of multiple bonds is still unclear,and there is still a lack of relevant norms at home and abroad to elaborate it in detail.In this paper,the numerical simulation method is used to make a tentative exploration on the stress situation of multiple shear bonds under the action of axial load with reference to the structural size of the Orchard Harbor wharf as an engineering example.The corresponding physical model test shows that the simulation results are of high accuracy.In addition,the distribution law of forces between the keys is obtained and the concept of distribution coefficient is put forward,which not only provides a direction for the design of multiple pairs of shear keys,but also lays a foundation for the analysis and study of the stress mechanism.

Abstract:Due to the continuous decrease of sediments coming from upstream,the area of sediment blocking in the Yangtze estuary has generally entered the state of erosion,and the coastal wetland resources are losing obviously.At the same time,the amount of dredging maintenance in the Yangtze estuary deepwater channel has also been reduced,and the dredged soil resources are becoming increasingly valuable.In recent years,the maintenance volume of dredging has been basically stable at 55 million～60 million m3/a.The utilization of dredged soil in the channel to replenish the nearby eroded shoal can be an important direction for the utilization of dredged soil resources in the future.To foster the ecological intertidal zone,filling to the shoal without cofferdam is a process way requiring further research.Taking Hengsha shoal as an example,by referring to the viscoelastic model of the dynamic response of the silty seabed under the action of waves and the measured rheological characteristic parameters of the dredged soil in the outer channel of Lianyungang Port,the attenuation rate of the wave height of the silty seabed under different incoming wave heights and different floating mud densities was studied and analyzed,and the results of maximum wave dissipation effect when the floating mud density was 1.20～1.30 g/cm3 were obtained.The ideas and methods of this paper can provide references for the filling process without cofferdam of dredging sediment from the Yangtze estuary deep-water navigation channel.It is also suggested to carry out experimental research on the dynamic rheological properties of dredged sediment from the Yangtze estuary deep-water navigation channel.

Abstract:In order to solve the problem that the upper and lower reaches of Hadashan hub of Songhua River cannot be continuously navigable without any navigational facilities,we use the water flow mathematical model to study the navigation flow characteristics of the reach from Hadashan to the Songyuan rolling dam.We validate the model by measured data,simulate the current status water flow of the river,analyze the navigation flow characteristics,simulate and study the scheme of connecting the upstream and downstream navigation technologies of the Hadashan hydro-junction,and obtain the navigation flow characteristic parameters.The results show that it can be solved that navigation problem of upstream and downstream connection for Hadashan hydro-junction by technology scheme of constructing ship lock or port in the upstream and downstream of the hydro-junction.It can provide references for the similar projects.

Abstract:Based on the project of four-level waterway construction from the Lancang River 244 mere Stone to Lincang Harbor and depending on the beaches from Xigua to Mengsong,this article illustrates the characteristics of waterway and hydrology.Because there are not enough waterway length and depth in the rivers and shoal groups of the canyon,single beach regulation causes the fall of river level in the upper shoals and the speed of the river and gradient slope change in a bad way,leading to new navigation obstacles.Analyzing the evolution rules of rapids and riverbeds and combining with the situations in the history,it researches the characteristics of the single shoal and shoal groups navigation obstacle,adopts the method of enlarging water-carrying section in the way of cleaning the rocks and solves the problem of single shoal navigation length and depth.Meanwhile,it adopts the combination of damming the river step by step and dredging in different sections to deal with the fall of the water level because of shoals and rapids connections.Therefore,it is concluded that the combination of cleaning rocks and damning can solve the puzzle of rapids connections and influences

Abstract:Qiankou rock ledge is one of the rapid shoals in the upper reaches of the Yangtze River.Based on the analysis of the reasons of navigation obstruction,we study the reef-cutting regulation by model tests.The influence factors of regulation project scheme consist of three depths (4,5 and 6 m) of reef-cutting,two levels (full blasting or partial one) of reef-cutting,and the reef filling tank.The results show that the different depth schemes have the basically same flow pattern,with transverse flow obviously weakened,and without obstruction of navigation.The full cutting scheme reduces the difficulty of navigation mark arrangement,decreases the number of the navigation mark,and reduces the maintenance and operation cost for this waterway section.So the advantages of this scheme are obvious.The bubble swirling water decreases to a certain extent and the flow pattern is further improved after reef-cutting.We recommend the scheme of channel regulation project of 5 m-depth and full reef-cutting blasting with the reef filling tank,because of the effective improvement of the waterway condition and the significant reduction of the waterway maintenance difficulty and operation cost.

Abstract:The navigable flow condition of the entrance area and connecting section of the approach channel in muti-line ship locks is a key research topic.Taking the navigation hydraulics test of the second-line lock of Guding water conservancy hub as an example,this paper studies the navigable flow conditions in the entrance and connecting section of the lower approach channel under the background of the construction of Guding second-line lock.The test results show that the velocity of reflux and cross flow in the entrance and connecting section exceeds related standard.Therefore,from the two aspects of layout of navigation wall and dredging approach channel connection section,this paper puts forward a variety of optimal layout schemes,and recommends the combination of layout of 70 m external cantilever navigation wall (50 m vertical wall+20 m external cantilever) and dredging connection section to improve navigable environment.The research results provide a reference for the optimal layout of the second line lock of the Guding hydropower station.

Abstract:In order to realize the initial opening of 6 m water depth in the section from Wuhan to Anqing section of the Yangtze River main line,it is necessary to carry out waterway regulation on this section.The section of Huguang—Luohuzhou river is one of the sections.In order to provide the basis for determining the waterway regulation idea and forming the regulation plan,the physical model test was carried out in the section of Huguang—Luohuzhou river.The result of trend prediction experiment shows that although the channel conditions of this section can meet the scale requirements of 6 m channels at present,if no protective measures are taken,the current favorable channel conditions is likely to develop in an adverse direction,or even fail to meet the regulation target requirements.The results of the typical years and serial years tests of the scheme show that the implementation of the regulation project to a certain extent limits the erosion of the middle and high beaches in the riverside beach of Muerzhou,improves the inflow conditions of the Huguang waterway and the Luohuzhou waterway,and is further conducive to the maintenance of the main navigation channel conditions.

Abstract:The Fomian beach，which is a reef extending the heart of the river between Fuling and Fengdu reach of the Yangtze River，causes strong cross flow and flow disorder in the flood season,so the ship must go upstream by crossing the river and conflict with the downstream route,resulting in endangering the safety of the ship’s navigation.By blasting partial reef of Fomian beach,we can improve the navigation flow condition and realize the ships “Keeping at the right and sailing side by side”.By establishing two-dimensional flow mathematical model of the Fomian beach to simulate the flow field of the multi-stage flow,we determine that the most turbulent flow is 24 500 m3/s.By simulating eight reef blasting schemes of different explosive depths under the most turbulent flow and comparing the flow velocity,transverse velocity,ratio of transverse and longitudinal velocity,ratio of propulsive and drag force,effect ratio of unit depth of each reef scheme and flow regime,we know that the optimal reef blasting scheme of 8.0 m explosive depth is the best.

Abstract:The distributions of navigation marks for the key tributaries of the Yangtze River trunk line are lack of uniform distribution principles and methods.We adopt the method of classification study according to the features of estuary topography and main channel layout,divide the estuaries into two types,which include coastal channel (or the main channel on the estuary side) type and the main channel and the tributary estuary have a certain distance type.We determine the types of navigation marks used for different types of river navigations,and propose the corresponding distribution schemes of navigation marks for different types of tributaries and estuaries in accordance with the general principles of marking the location of tributaries and estuaries,marking the intersection of the main and tributary channels,marking the boundary of the main channel and the tributary channel,and the obstruction of navigation,and suggesting information about tributaries and estuaries.It can provide references for the similar projects.

Abstract:In order to master the hydrodynamic and sedimentary variation of the water area front the sluice after the extension of intake channel,we systematically analyze the hydrodynamic and sedimentary processes with the changes of the surrounding shoreline when the sluice is opened and closed,which are based on the fixed-point observed data during the flood season and spring tide (June 17-19,2015) in the intake channel of the downstream reach of Sanjia Port sluice.The results show that,with the regulation projects being constructed recent years,the reach has been propagated downstream about 1.3 km,and there are double low-velocity zones in the intake channel caused by berthing ships and shoal.The intake channel front sluice is controlled by tide,and tidal current is rotational flow.The hydrodynamic of intake channel is weak when the sluice is closed,and the velocity in upstream reach is slower than 0.1 m/s.The sediment transports to upstream.The distributions of sediment concentration and the instantaneous flow velocity are both single peak when the sluice is opened,but the velocity decays rapidly.

Abstract:The current general BIM modeling software can not reflect the large settlement in reclamation works,so the BIM application management system for the reclamation engineering is created by the secondary development based on commercial softwares.The monitoring data can be imported in real time and dynamic correlation between the BIM model and settlement monitoring data during construction can be achieved.The system integrates the BIM model generation using borehole data,4 common monitoring data analysis and management functions.The construction schedule and engineering quantity management can also be achieved by calling Navisworks.In addition,a special database website is developed,which provides a complete set of solutions for the data storage,safety strategy and data archiving by means of configuring permissions,backuping in different places and data encryption.This system has been successfully applied to the practical project and achieved good results.

Abstract:The BIM technology based on Autodesk platform lacks a structural calculation software matching the modeling software Revit in the design of water transport engineering structure.A method for coupling general finite element structural calculation software ANSYS and Revit is proposed.Since Revit can only build the water transport engineering parameter model in the family environment,the Revit basic primitive types are programmed and classified to give structural properties to the loadable family.The Revit API technology is used to filter the geometric information,property information and material information of the structural model,and then the extracted information is compiled into ANSYS command stream file to realize the data transformation of structural calculation software ANSYS and BIM modeling software,and optimize the mapping grid partitioning process of ANSYS structure calculation based on Revit Boolean algorithm.Finally,the feasibility of this method in structural calculation is verified by using the main project of a ship lock.

Abstract:In view of the limitation of the traditional design,we apply the BIM technology to the construction drawing design of triangle gate of Honglan ship lock on the Qinhuai River.The advantages of BIM technology in four aspects including the collaborative design,visualization,collision check,engineering quantity statistics and plotting are expounded.The research shows that the application of BIM technology can solve problems such as inadequate depth of cooperation among different majors,lack of intuition of 2D drawing,frequent occurrence of mistakes,omission and collision,etc.It realizes the 3D modeling of spatial structure with complex curved shape and achieves the goal of design optimization and improvement of the design quality.

Abstract:Aiming at problems of inconsistent data format,incomplete basic data system，inadequate data resource sharing and narrow application area of the system in Guangdong inland waterway surveying and mapping，we study the management of Guangdong inland waterway surveying and mapping results,construct the database of Guangdong inland waterway surveying and mapping results,and develop independently the basic platform of GIS,seamless access and display of multi-source data,application of modern information technology such as 3D GIS and Internet of Things，which realize the integrated management of data acquisition,production，update，storage and sharing utilization of inland waterway surveying and mapping in Guangdong Province，and can also be used in three-dimensional waterway display,typical section analysis，depth data analysis，shallow point analysis，siltation trend analysis,engineering applications and other aspects to provide a support for the Guangdong channel management department in channel management and maintenance of information means.

Abstract:In view of the differences of planning of geotechnical investigation requirements between Chinese and foreign standards,comparative analysis and research on planning of geotechnical investigation requirements of Chinese standard (GB 50021—2001 Code for Investigation of Geotechnical Engineering,JTS 133—2013 Code for Geotechnical Investigation on Port and Waterway Engineering)，European standard (Eurocode 7：Geotechnical design) and American standard (ASTM codes related to geotechnical investigation) were carried out.The study found that there were significant differences between the Chinese and foreign survey standards in terms of stage division,content,method,spacing and depth of exploration points,number of trials,optimization during surveying,control and monitoring of construction phases,and other aspects of the planning of investigation.We put forward the application points of overseas geotechnical investigation standards,which will help industry colleagues understand and use overseas investigation standards,and be beneficial to the international integration of Chinese standards.

Abstract:When applying the vibroflotation compaction method to treat the large-area hydraulic filled sand foundation,two key technical problems are encountered:1)How to control the clay content of the reclamation material until less than 15%；2)It is difficult to achieve the target depth once during deep underwater vibroflotation.So,combining with two overseas projects,we carry out a research on corresponding technical countermeasures.The test results show that the proposed technical countermeasures can better solve the key technical problems.

Abstract:The second line shiplock of Mengtli hydroproject in Beijiang River of Guangdong Province situates in a mixing zone with carbonaceous limestone,carbonaceous shale and siltstone,limestone interbedded and soft rock & intensive karst zone developed.In view of the stability of deep foundation pit,stability of excavated slope higher than 60 m,karst treatment，we propose reinforcement measures and construction techniques for the trench of the earth wall,and adopt a new type of wall cofferdam structure in the lower part of the wall and upper retaining wall,which effectively reduces the backfill,excavation and internal force of the construction platform,and meanwhile provides a reliable basis for optimizing the foundation pit construction plan and lays a solid foundation for ship lock construction.

Abstract:Aiming at the foundation consolidation problem of vertical drains under vacuum preloading,considering the influence of nonlinear of foundation soil and the parabolic variation on the horizontal permeability coefficient of the smearing area and loading changes with time,we derive a general solution of vertical drain consolidation under vacuum preloading,and verify the rationality of the analytical solution by the study of degradation and comparative analysis.Based on this general solution,we obtain the corresponding special solutions of two special loading modes for instantaneous loading and linear loading,compile the calculation program,and draw the curves of the consolidation process of the vacuum preloading vertical drain according to the special solution.The results show that the nonlinear of foundation has a great effect on the consolidation characteristics.The greater the ratio of the compressibility index to the horizontal permeability index is,the slower the consolidation rate of the foundation is.The greater the initial stress is,the faster the consolidation rate of the soil is.The vertical drain pore pressure dissipation rate under linear loading is slower than that of the instantaneous loading.

Abstract:The repressive layer plays an important role in improving the stability of the seawall on the soft soil foundation,but the width and thickness are mostly calculated and selected by empirical formula and limit equilibrium method.Based on the strength reduction method,this paper studies the relationship between the width and thickness of the repressive layer and the safety factor of the seawall by using ABAQUS finite element software.First,the basic principle of strength reduction method is introduced.Then the relevant sea wall model is established.The width and thickness of the repression layer are added to the model in the form of the width and size of the linear load,and the safety factor and the potential sliding surface are calculated by taking the convergence of numerical calculation as the evaluation standard.The reasons of the change of safety factor and width of repressive layer are analyzed from the angle of sliding surface.The results show that the stability of the seawall is proportional to the width and thickness of the repressive layer,and the safety factor and the sliding surface do not change after the width exceeds a certain number.

Abstract:In view of the current engineering situation in which the CPTU data of hard soil are difficult to acquired in offshore investigation area,based on the first large-scale application of large penetration force CPTU equipment,comparative analysis is conducted with popular CPTU interpretation correlations for the physical and mechanical properties of Sanya offshore hard soil among seabed CPTU results,lab test result and SPT results.Comparative analysis shows that the internal friction angle of sand and the undrained shear strength of clay from CPTU test are slightly higher than that from lab soil test and SPT.The study on the hard soil with large penetration force CPTU provides useful experience and reference for the similar engineering.

Abstract:In order to enrich the domestic industry’s research on the engineering characteristics of super-long steel pipe pile under coral reef limestone geology,combining with the pile foundation construction of a hydraulic project in East Africa,we analyze the rules of pile sinking of steel pipe pile under this geological condition.The 1.2 m-diameter steel pipe piles are used in this project.The anchor pile method of static load test is used for three piles,with 12 mm,18 mm and 24 mm wall thickness respectively and the maximum pile length of 71.2 m.The pile bearing layer is coral reef limestone and has a maximum into the bearing layer of 31.8 m.Through the low-temperature sensitive fiber grating sensor embedded in the pile,the engineering characteristics of the coral reef limestone under different pile top loads are revealed by the pile-sinking rule and static load test,It provides reference for the design and theoretical research of steel pipe piles under coral reef limestone.

Abstract:In view of such problems as narrow space inside the caisson cell of gravity wharf,difficulty in drainage,difficulty in strengthening the internal packing compactness,and difficulty in ensuring the integrity of the side wall and bottom of the caisson,the static contact test results of four caisson compartments with different vibroflotation parameters were compared and analyzed.The three vibroflot parameters(vibroflot number,compacted current and retained vibration time)affecting the reinforcement effect were optimized,and the optimal working conditions of single point vibroflot,compacted current 80 A and retained vibration time 20 s were finally determined.This working condition can reduce the influence of vibroflot on the caisson and save the construction cost while ensuring the compactness of the packing.It is also found that there is a conic curve correlation between the vibro-compaction current in the caisson and the average cone resistance at the corresponding position.

Abstract:The bridge connection and landing project of Daxiaoyu hill reclamation project in Daishan County,Zhoushan City adopts sloping breakwater structure,and the foundation treatment adopts two types:plastic drainage board and vibrating sinking-pipe macadam pile,among which,vibrating sinking-pipe macadam piles are all constructed on the sea,which is the longest vibrating sunken pipe gravel pile applied to the domestic port and waterway engineering up to now.A set of key technologies for the gravel piles construction involving the marine vibro- pipe-sinking installation is established against the technical difficulties previously faced during construction by making necessary modifications on the pile-driving barges,optimizing the pile layout,working out a set of effective quality assurance measures and monitoring measures for gravel delivery,effectively solving a series of difficulties such as low equipment operational efficiency,slow positioning,poor positioning precision,non-sinking gravels,insufficient grouting,and poor compactness.

Abstract:In order to solve the problem of hard rock layer in dredging,which cannot be or is not suitable to be treated by blasting,this paper takes Angola Luanda SONILS quay wall project as an example,and stndies the application of mechanical rock breaking method in dredging.Based on the analysis of the practical conditions in the field,this paper puts forward the best treatment scheme for rock breaking by using rock hammer or piling barge,and selects the appropriate construction parameters such as hammer shape,hammer weight,free fall height and arrangement of rock impact points through theoretical analysis,and makes experiments and improvements.In the process of implementation,attention should be paid to the wear and reinforcement of the steel wire and hammer tip as well as the sealing of the pile tip.The results show that after mechanical breaking,the hard rock layer can be easily cleaned by grab dredger,has good economic benefits,and may serve as reference for the similar project.

Abstract:With the rapid development of dredging technology,the direct excavation of large-scale weathered rock by large dredgers becomes the main means of construction.Taking the “Electricity-Tianniu” series cutter suction dredger as an example，through a series of measures,such as rational selection of cutter head and cutter tooth,reduction of cutter tooth wear and softening rock,the productivity of ships is effectively improved and construction cost is reduced.Comparing with the traditional reef blasting and reef clearing construction technology,the cutter suction dredger excavation of weathered rock has the advantages of high construction efficiency and low cost.