Abstract:In the context of climate change，extreme weather and water level events occur frequently.To study the long-term evolution characteristics of extreme tide levels in the Yangtze Estuary，this paper analyzes the tendency and the return period of the extreme tide level in the Yangtze Estuary based on the methods of the extreme value theory，using the observed data in the last 33 years.The results show that the annual extreme water level at Xuliujing station shows a slight downward trend，which is directly caused by the decrease of local mean sea level due to the reduced river discharge of Datong station.The storm tide level caused by Typhoon Winnie in the Yangtze Estuary is estimated to be a once-in-a-century event according to the Block Maximum model.However，it is projected to occur once in 60 years based on the results of the POT model，with the once-in-a-century return period tide level reaching 7.0 m.Calculation of the return period of tide level is essentially a process of replacing probability with frequency and extrapolating from sample to the whole，with a certain degree of uncertainty.Its significance lies in using obtainable data to calculate the risk rate of an event，providing a basis for engineering design or risk management.

Abstract:To improve the wave-dissipation and water permeability of the horizontal plate breakwater，we design a horizontal plate breakwater with semi-perforated on wave-facing side.Under different conditions of relative plate width，submerged depths，and wave heights，we use physical modeling tests to study the transmission coefficient Kt，reflection coefficient Kr，and energy dissipation coefficient Kh of the two types of horizontal plate breakwaters including the non-perforated type and the semi-perforated on the wave-facing side type，and systematically compare the wave-dissipation performances of the two types of horizontal plate breakwaters.The results show that under test parameters，the transmission coefficient of the semi-perforated horizontal breakwater on the wave-facing side is smaller than that of the non-perforated horizontal breakwater，and the transmission coefficients of the two types of horizontal plate breakwaters both reach the minimum value when the conditions of relative plate widths are 0.166 or 0.212.While the trend of the reflection coefficients of the two types of horizontal breakwaters is similar，and the reflection coefficients of the semi-perforated horizontal breakwater on the wave-facing side are small.The overall reflection coefficients of the two types of horizontal plate breakwaters are similar in trend，and the overall reflection coefficients of the semi-perforated horizontal plate breakwaters on the wave-facing side are small；the overall energy dissipation coefficients of the semi-perforated horizontal plate breakwaters on the wave-facing side are larger than that of the non-perforated horizontal plate breakwaters，and they reach the maximum values when the relative widths are 0.166 or 0.212.The wave dissipation performance of the horizontal plate breakwater with semi-perforated on the wave-facing side is better than that of the non-perforated breakwater.

Abstract:The high-pile wharf structure is damaged to various degrees during the service life and the safety of structure is degenerated.To ensure the long-term safe operation of wharves，it is necessary to monitor their operating state and timely forewarn the risks through real-time monitoring.In this paper，a forewarning model of high-pile wharf structure safety monitoring is proposed，and design control values of different structural states are used as the forewarning thresholds of different levels.Each level forewarning value corresponds to different risk levels，and the disposal measures are proposed for different-level forewarning.The forewarning model is applied to monitor safety of a high-pile wharf in Nanjing Port，including displacement of the wharf structure and strain of the piles under variable load in real time，and the three-level safety forewarning thresholds of the displacement of the wharf structure and the strain of the piles are calculated and set.The results show that the setting of wharf safety forewarning threshold and the countermeasures of safety alarm are scientific and effective，which can realize the purposes of overall technical state assessment and safety forewarning of all the operating condition of the wharf structure.

Abstract:Based on an engineering example，the seismic response characteristic of high piled platform structure with eccentrically distributed plane stiffness of beam system is studied by response spectrum method and time history analysis.It shows that results of response spectrum method and artificial wave time history analysis are close under transverse earthquake action，while the result of natural wave is different due to wave selection.The calculation results of piles are close for 2D and 3D model，and the peak shear force of transverse beam model are close for 2D and 3D mode，while the peak bending moment of which differ greatly.The results of 3D response spectrum method and artificial wave time history analysis are close under longitudinal earthquake.The comparison of different calculation modes shows that the 3D response spectrum method has good adaptability.If the seismic precautionary intensity is greater than 7-degree，PHC pile is not suitable for this type of platform.Parametric analysis of the beam-plate connection rigidity coefficient λ shows that the effect of λ change on the internal forces of transverse or longitudinal beam is greater than that on the pile，the effect on the bending moment of transverse or longitudinal beam is greater than that on the shear force，and the influence degree under the longitudinal earthquake is greater than that under the transverse earthquake，which indicates that the constraint state between plate and beam changes the structural stiffness distribution，and then has regular influence on the seismic effect.

Abstract:To calculate the wave loads of closely spaced pile breakwater structure，we carry out the physical model test to do research on the wave load of closely spaced pile breakwater based on a breakwater project.The results show that the theoretical formula of wave load for vertical-walled structure can be calculated for the closely spaced pile breakwater structure，and the results of the OCDI formula is similar to the test results.The wave load along the axis of the closed-pile structure presents a trend of larger body and smaller head.Oblique waves have a certain influence on the wave load on the closely spaced pile breakwater structure，and the reduction coefficient of the OCDI formula can be used for approximate evaluation.

Abstract:The shear resistance of the bottom plate of a caisson often controlls the thickness of the bottom plate，and there is limited research on the distribution law of shear force.To address this issue，finite element method is used to calculate different combinations of working conditions.The maximum shear force distribution at the edges of plates with four-side fixed under uniform load，and the relationship between the maximum shear force and the thickness，length and aspect ratio of the plate are studied.The general rule of the ratio of maximum shear force to average shear force is obtained.The results show that the distribution of shear force at the edge of the plate follows a parabolic shape.The maximum shear force at the edge of the plate is less than the maximum shear force calculated by the elastic thin plate theory.Under the same scale and load conditions，the maximum shear force at the edge of the plate will decrease as the thickness of the rectangular plate increases.As the size of the rectangular plate increases，the maximum shear force at the edge of the plate will rapidly increase，and the ratio of the maximum shear force to the average shear force will also increase.For commonly used caissons longitudinal and transverse partition wall spacing and bottom plate thickness，the ratio of the maximum shear force at the edge of the plate to the average shear force is usually 1.3 to 1.6.This paper summarizes the relationship between shear force distribution and grid scale,aiming to provide reference for similar engineering designs.

Abstract:In response to the problem of soil pressure distribution behind the newly built sheet pile wall in the upgrading and renovation of gravity walls，the paper studies the distribution law of soil pressure at different distances between the newly built sheet pile wall and the existing gravity wall.Finite element numerical simulation and theoretical formula calculation are used to compare and analyze the distribution of soil pressure.It is concluded that the soil pressure acting on the front sheet pile wall is less than the theoretical active soil pressure，indicating there is a silo effect.It is suggested that when the front sheet pile wall is installed in the gravity wharf reconstruction project，the size of the silo should be rationally selected by the formula，or the soil pressure exerted on the sheet pile wall should be calculated by the finite element method according to the distance between the newly built sheet pile wall and the existing wharf wall，to avoid conservative or radical design.

Abstract:As a large-scale embankment structure，the quantitative calculation of the carbon emission of twisted-king block is of great significance for energy saving.Based on the LCA theory，this paper divides the materialization stage of twisted-king block into five stages，material production，material transportation，component manufacture，component transportation and site construction.The carbon emission measurement model is constructed to calculate the carbon emission in the materialization stage.Taking a large embankment as an example，the steps of measuring carbon emission is demonstrated.The results show that the carbon emissions during the materialization stage mainly come from the materials production and transportation.By comparing the carbon emissions of different transportation distances and patterns of sand and gravel，it is concluded that the carbon emissions can be effectively reduced by using nearby materials or waterway and railway transportation for long distance transportation.By comparing the carbon emissions of different fuel vehicles，the carbon emissions of gasoline vehicles and LNG vehicles are lower than that of diesel vehicles.

Abstract:Regarding the complicated factors affecting the force of T-type underground continuous wall structure，this paper analyzes the wharf structure by using the vertical elastic foundation beam method and STAAD software combined with engineering examples，and investigates the influence of different model unit division accuracy，depth of the ground wall and m value of the backfill on the structure of the T-type underground continuous wall.The results show that with the improvement of model element division accuracy，the bending moment of the underground continuous wall increases at sea side，decreases at land side，and the bending moment of the anchor wall structure changes in a contrary way.Finally，the internal forces of both structures tend to be stable.Under the premise of overturning stability，the sea side bending moment of the underground continuous wall decreases，the land side bending moment increases，and the displacement decreases as the depth of the bottom of the wall increases.With the increase of m value，the bending moment on the sea side of the anchor wall increases，decreases at land side，and the sensitivity is higher.The research conclusions can provide references for the design of wharf structure using T-type underground continuous wall.

Abstract:Based on the risk of coal pile collapse caused by path planning during stacking and reclaiming operations in the cabin of coal transport ships，this paper proposes a simulated clearing machine reclaiming path planning method based on edge information extraction from layered point clouds to prevent coal pile collapse.Firstly，the original 3D point cloud data is collected using a two-dimensional laser scanning experimental device.The point cloud data is simplified through coordinate conversion，denoising filtering using direct filtering algorithm，and random sampling simplification algorithm.Based on the slicing method，the calculated coal pile volume and mass are obtained，and the incoming coal is accurately counted.Then，the edge information of each layer of coal pile surface is extracted.The edge information of different layers of coal pile is combined to build the edge model of the entire coal pile surface，and the edge rest angle of the coal pile to be taken is calculated in real-time computing to realize the early warning information of coal pile collapse.Finally，based on the linear interpolation method，the material retrieval path planning is carried out，and a simulated cleaning machine execution mechanism operation path to prevent coal pile collapse is provided.

Abstract:To systematically study and analyze the key differences between shore-based LNG refueling terminals and LNG terminals，and provide targeted theoretical basis for design，the essential differences between the two terminals in terms of representative ship type，port site selection，operation process and operation volume are analyzed by means of normative analysis，practical analogy and logical reasoning，and the overall design points in terms of safety design and fire protection design are put forward.The results show that the shore-based LNG refueling terminal is different from the general cargo terminal and the dangerous cargo terminal，and it is a kind of port support terminal with special characteristics.Fire risk and fire control design of wharves should formulate targeted fire prevention codes.The fire risk of wharves is class A，and the fire control design should be configured according to the initial fire control requirements of wharves.When using water replenishment or combined water and land replenishment，the main nature of the refueling terminal should not be changed，and the safety emergency plan and on-site safety management should be made with reasonable reference to the practice of LNG terminals.

Abstract:Based on the comprehensive wharf project of Suntuan operation area in Huaibei Port area，Anhui Province，we carry out the on-site test and parameter optimization research on large diameter prestressed high-intensity concrete (PHC) pipe pile sinking for high-pile wharf in inland rivers.After obtaining the parameters of pile sinking through the initial geological survey report，we carry out the feasibility analysis of pile sinking and the improvement of construction planning，conduct trial pile sinking，high and low strain and static load tests，and optimize pile foundation design parameters based on the test results.The results indicate that the feasibility of the construction process，pile sinking equipment，pile sinking control parameters，and stopping hammer standards for large-diameter PHC pipe piles of high-pile wharf in inland rivers are verified by the depth of the pile tip entering the bearing layer and the final penetration results in the comprehensive pile sinking on-site test.The adjustment coefficient range for the ultimate lateral friction resistance standard value and ultimate pile end resistance standard value for unit area of large-diameter PHC pipe piles of high-pile wharf in inland rivers is determined by 5% to 10%.The ⑦ layer of fine sand as the bearing layer of the pile foundation is proposed，and the pile foundation parameters are synchronously optimized.

Abstract:Taking the expansion project of a port in East Africa as an example，we elaborate the design method of water area dimensions in the narrow harbor，including basin width with the navigational channel function，turning basin diameter，and entrance width.We conduct a comparative study on domestic and foreign standards regarding the calculation methods of water area dimensions，determine the preliminary design scheme for water area plan dimensions based on the experience，and carry out a ship maneuvering simulation test to verify the rationality of the design scheme.The results show that the water area layout of this project is reasonable，which can meet the requirement of ship navigation，and effectively reduce dredging volume and control engineering investment.

Abstract:Regarding the problem of navigable water flow conditions within the intermediate channel of decentralized ladder locks，the present study delves into the impact of the intermediate channel section type on this aspect.A formulation for working head in the middle channel of rectangular section and trapezoidal section is proposed.Mathematical numerical simulation is used to study the influence of different section shapes on navigational flow conditions.The results show that:1) The working head of the intermediate channel filling and emptying water is consistent，and its water level shows periodic changes.2) Variations in section type have less effect on the flow trend and the time of water transfer at locks.3) Compared with the rectangular section，the intermediate channel with trapezoidal section can effectively reduce the water level variation，oscillatory wave height，maximum water surface slope drop，and maximum longitudinal flow velocity during the upstream lock discharge.This study provides theoretical support for the design of intermediate channels in decentralized ladder locks.

Abstract:There are many tributaries along Pinglu Canal with large branch drop，and the sudden flood of tributaries has a great impact on the navigable flow conditions of the canal.This paper selects Shaping River reach with large inlet angle，large branch and trunk confluence ratio and large river bottom drop as the research object，and adopts 1  50 normal river model test to carry out systematic experimental study on navigable flow conditions in this reach.The model test results show that due to the large sudden flood of tributaries and the large bottom drop of the branch river，the lateral flow velocity in the canal channel is large and the flow pattern is disordered.Coupled with the restriction of the railway bridge upstream of the tributary estuary，the arrangement length of the energy dissipation measures is limited，and the energy dissipation effect cannot be achieved.The analysis suggests that the main problem is that the lateral flow velocity of the canal is large after the tributary flood flows into the canal，so the treatment plan mainly solves the problem of “regulating water flow + energy dissipation”.Diversion levees，diversion piles and bottom inclined permeable separation levee are arranged at the interchanges，and energy dissipation measures such as deadling pool and dissipation sill are adopted in the tributaries.A series of scheme comparisontests are carried out.It is found that the navigable water flow under optimization scheme Ⅲ meets the navigable requirements and does not affect the railway bridge in the tributaries.

Abstract:Compared with the common canalization project，there are some technical problems of dam site selection，such as the connection of the lowest navigable water level between the hydro-junction and the analysis of the impact on the power generation of the built hydro-power station，when the dam site is added to the existing channelization cascades.The research cases are few.Taking the dam site selection of Shuidongba navigation hydro-junction project in the Jialing River as an example，we analyze advantages and disadvantages of conditions of water depth，river regime，topography and geology，and submergence loss of the section of the reservoir tail，put forward ideas of preliminary selection of dam site，layout of key buildings and determination of normal water level of key project，and carry out the comprehensive dam site selection from the aspects of water level connection，reservoir landscape，influence on power generation of built power stations，construction diversion and project investment，etc.The conclusion is that the dam site of Fuxingchang is recommended as the dam site of Shuidongba navigation hydro-junction.

Abstract:Tributary inflow will result in localized lateral flow in the main steam as well as significant water level fluctuations.Changes in flow conditions can adversely affect the safe navigation of the canal.Under natural conditions，lateral flow velocities at tributary confluences in localized areas exceed the minimum requirements of the navigational criteria，which seriously affect the safe navigation of the waterway.The optimization of the exceeded section of the river is required.In view of impact of flood discharge tributaries on navigable flow conditions in canals during flood season，the renormalization group (RNG) k-ε turbulence model is adopted to carry out the three-dimensional fine numerical simulations，and navigational conditions in the confluence area under different combinations of flood flows are studied.The results show that although the widening of the channel can effectively improve the flow conditions in the confluence area，the lateral flow velocities in some areas still exceed the standard under the original design scheme.The measures are adopted for the optimized scheme，such as moving down the connecting section，setting up water diversion retaining walls，and widening the river way and etc.When the optimized scheme is applied，the overall navigational conditions in the confluence area are satisfactory，and the flow and water level conditions can meet the requirements for safe navigation of ships.

Abstract:Aiming at the problem of navigation-obstructing flow in Xiongcheng reach of the middle Yangtze River，we use a mathematical model to study the flow characteristics of the reach.The results show that the riverway is narrow and curved，the beach is not high，and affected by the outflow of Dongting Lake，the three-dimensional characteristics of flow in Xiongcheng reach are obvious，and there are many flow structures such as crossflow，circulation and backflow，which have great influence on ship navigation.When the flow of the trunk line is 25,000 m3s to 30,000 m3s，and the water level of Dongting Lake is high，ship accidents are likely to occur，so it is necessary to remind ships to navigate with caution.

Abstract:Mangniushao Beach is a major obstruction to navigation in the middle reaches of Songhua River.The shallow channel，narrow channel and rapid flow at the mouth of the beach，accompanied by cross-flow and other obstruction to navigation，have seriously affected the navigation of ships and the construction of eco-tourism channel.To solve this problem，two-dimensional numerical simulation is used to study the characteristics of the obstructing current in Mangniushao reach，and the effects of three channel regulation schemes are compared and analyzed.The results show that the navigable water depth of the beach section is greater than 1.78 m，the average slope in dry season is only 0.29‰，and the average hydraulic parameter of rapids abating is far less than 2.06.The flow pattern is good and meets the requirements of channel management.The research results can provide scientific basis for the selection of channel regulation scheme of this kind of beach.

Abstract:The sector gate of the ship lock can hold water in both directions and operate under some water head，and has the outstanding advantages of opened lock operation and filling and emptying by gate gap，which can significantly improve the operation efficiency of the ship lock.In view of the high quality development requirements of inland water transport and the technical requirements of opened lock operation of many new ship locks，this paper systematically summarizes the practical application and the related research progress of opened lock operation and filling and emptying by gate gap of sector gate，and expounds the main influencing factors affecting its application.Based on the analysis of the main problems existing at present，it is proposed that the operation experience should be combined with the test and research of relevant technical indicators to create the basic theory and standard of opened lock operation and filling and emptying by gate gap so as to provide scientific basis for its wide application.

Abstract:Regarding the problem that the existing anti-collision arresting system does not adapt to the new situation of large ships and formation of new ships，an active safety arresting scheme of large ship locks is proposed.By using a robotic arm to autonomously lay cables，the tension on the blocking cable is transferred to the friction energy absorption unit through the brake belt and guide pulley.The friction brake on the friction energy absorption unit gradually absorbs the kinetic energy of the fleet within the braking distance，and a series of methods are used to ensure the safe parking of the fleet during the lock period，eliminating the safety risks of ship stalling，speeding and hitting the ship's gate.At the same time，The feasibility and effectiveness of the arresting scheme are verified by numerical simulation.The results show that the scheme can satisfy a group of lock passing fleets with a displacement range of 8，750 t(no load)~30，000 t (full load)，the entering speed of 0.5 ms，the braking speed of 20 m braking distance，and the safe stopping of the ship.The safety of the miter gate of the ship lock and passing fleet are effectively ensured.

Abstract:In response to the complex terrain environment，large construction area，and multiple disciplines involved in the dock project，there are issues such as inaccurate terrain data，low efficiency of construction collaborative management，and inability to transmit project data.This paper focuses on BIM+GIS data fusion，fusion data processing and application，and conducts secondary development based on domestic GIS platforms to achieve model lightweight，model data coding，and one click web service publishing etc. ,to achieve digital business management driven by fusion data，and form a set of BIM+GIS integrated data application solutions for terminal engineering.This article takes a certain dock project as an example to conduct digital application verification of research results in the design and construction stages of dock construction，which improves the digital management level of dock projects，and also provides a way of thinking for the full life cycle management of dock projects.

Abstract:Traditional 2D design of ship lock metal structure has problems such as large drawing calculation workload，long design cycle，limited professional collaboration，and difficulty in drawing and reading complex structures.BIM technology can be used to unify the design route of metal structure，complete BIM model creation，finite element calculation，engineering drawing export，etc. ,based on standard templates，and realize forward design of metal structure BIM.BIM technology has the characteristics of modular design，collaborative design，parametric design and visual design，and using it to carry out the metal structure design of ship lock can shorten the design cycle，promote the process of product standardization and serialization，promote inter-professional collaboration，realize the driving modification and automatic update of parameters，and accurately express and convey design intent.Practice shows that compared with the traditional 2D design mode，the use of BIM technology for ship lock metal structure design can effectively improve the design efficiency and quality，and realize the efficient transmission and integrated management of information，which has significant advantages.

Abstract:In response to the issue of “bottleneck”in BIM software for channel design in waterway engineering，key performance requirements analysis and software development are conducted for the channel design software.Based on a 300，000-ton channel renovation and expansion project in China，this article introduces the application of self-developed software in channel design，including 3D geological model，channel parameterization design，automatic section drawing，quantity calculation，and interaction with other BIM software.The results show that the self-developed BIM software for channel design conforms to the design habits，and can meet the current BIM design requirements of domestic channel engineering.This achievement will also provide reference for the independent and controllable design software of similar channel projects.

Abstract:When constructing interpenetrated densely packed pile foundations at sea，problems are prone to occur such as collision of piles below the mud surface，and obstacles to pile sinking by pile driving vessels caused by already constructed piles.By using BIM technology modeling，pile diameter expansion simulation，and dynamic adjustment of pile driving parameters，the maximum allowable error of pile driving collision and deviation is analyzed，and the early-warning and prevention of pile driving collision are achieved.By using BIM 3D printing technology to make scaled models of seabed，piles，and pile driving vessels，bringing in combinations of water level simulation and positioning devices，dynamically and accurately simulating offshore pile sinking，verifying the rationality of piles position layout and determining feasible pile sinking construction sequences.

Abstract:To reinforce the soft soil foundation formed by dredged and filled marine sediment，experiments such as static drainage consolidation methods with surcharge preloading，and dynamic drainage consolidation methods with dynamic compaction construction are conducted in the backfill area of the coastal reclamation in Shantou City.The static-dynamic drainage consolidation method of “dewatering + surcharge loading + dynamic compaction” is used to reinforce soft soil foundation formed by marine silt and sand backfill.Through field tests，the settlement of various foundation layers，water level and pore water pressure，and soil displacement changes during construction are studied.Geotechnical tests and in-situ tests are conducted on the foundation before and after treatment，verifying the treatment effect of this method on marine silt and sand.The research shows that this static-dynamic drainage consolidation method can significantly improve the bearing capacity characteristics of the backfilled soft soil foundation，and can be widely used in soft foundation reinforcement projects for land reclamation from the sea.

Abstract:The large diameter steel cylinder structure is a new type of hydraulic structure that has emerged in recent years.It has advantages of simple structure，fast construction speed，good structural stress conditions，low cost，and can adapt to the hostile environment of deep water and large waves，which has broad application prospects in soft soil areas.During the construction of steel cylinder，its stability under wind and wave load is the main issue of engineering concern.Taking the steel cylinder revetment of a wharf project in the East China Sea as the research object，we study the failure mode and stability of the steel cylinder structure through the geotechnical centrifugal model test，and analyze the characteristics of displacement，the cylinder wall soil pressure，cylinder body strain and etc.The results show that the failure mode of steel cylinder structure on soft soil foundation under horizontal load is mainly inclined failure，not overall translation.The ultimate load of the steel cylinder is about 2 times of the horizontal load when it loses stability and fails.Under the action of horizontal load，the soil pressure of the cylinder wall on the land side gradually increases，and the soil pressure of the cylinder wall on the sea side gradually decreases，and the soil pressure of the cylinder wall on the land side is significantly greater than that on the sea side.The strain of the cylinder increases with the depth，and the stress of the cylinder at the bottom of the steel cylinder is significantly greater than that at the top.

Abstract:Aiming at the problem of evaluating the quality of the pile body accurately based on the temperature field of the hydration heat of the cast-in-place pile，we use the characteristics of the concrete hydration heat temperature changing approximately linear with radial distance (from the center of the pile cross-section) within the range of the radial distance greater than 0.5 times the pile radius，and build the method for calculating the deviation of the reinforcement cage based on the temperature of two symmetrical measuring points on the reinforcement cage.Combining with the simulation analysis of the hydration heat of the defective pile，we systematically analyze the influence of the geometric characteristics of the defect and the change of thermal parameters on the temperature field，and propose the method for judging the presence of defects and analyzing their spatial distribution position based on the characteristics of the temperature-depth curve obtained from temperature measurement points along the main reinforcements.Combining field tests and comparison with low-strain and cross-hole ultrasonic testing results，we verify the feasibility of the method.

Abstract:Both vacuum preloading and vacuum well dewatering can be used for the improvement of soft soil foundation.Apparently，both of them drain out pore water through vacuum and make the soft soil consolidate.However，if the understanding of the key differences between the two technologies and mechanisms is not clear，it is difficult to effectively guide the on-site construction.There are significant differences between vacuum preloading and vacuum well dewatering in vacuum pumping equipment，vertical drainage channels and sealing boundaries.The drainage mechanism of the two is also fundamentally different.The mechanism of vacuum preloading is that the soil mass is consolidated horizontally towards prefabricated vertical drains(PVD) under negative pressure difference，and the upward flow of water in the PVD is independent of gravity.The mechanism of the vacuum well dewatering is that the groundwater level decreases due to the pumping of group wells，thus makes the soil unit weight to change from buoyant unit weight to the wet unit weight，resulting in additional loading and consolidation，and the water inside the well pipe is affected by gravity.On the basis of the difference analysis of process and mechanism，the differences between vacuum preloading and vacuum well dewatering in 10 key aspects are further clarified，including reinforcement mechanism，influence depth，vacuum propagation at different depths，soil horizontal deformation，relationship between upwards water flow and gravity，influence of vacuum pumping location，connectivity state with the outside environment，cause of influence area，changes in groundwater level，and formation of unsaturated zone.

Abstract:The mix ratio of sand-mudstone mixed filler is a key factor affecting the bearing capacity and stability of the wharf foundation.To study the creep mechanical properties of sand shale mixed fill soil under different mix proportions，shear creep tests are carried out.The results show that under the same mix ratio，the instantaneous and creep strain and the initial and steady creep rates increase gradually with the increase of the loading level of shear stress.When at the same loading level，the initial，steady-state，and ultimate accelerated creep rates，as well as instantaneous and creep strains，all show a decreasing trend with the increase of the proportion of mudstone particles in the mix ratio.The long-term srength reduction of mixed filler is relatively large，ranging from 50.53% to 66.95%，and the long-term strength decreases with the increase of the proportion of mudstone particles in the mix ratio.The research results can provide some references for the long-term stability evaluation of the mixed sand-mudstone filling foundation of the wharf.

Abstract:The construction control network of waterway engineering is an important issue in canal construction.Taking the establishment of Pinglu Canal construction control network as an example，we determine levels of horizontal control network and elevation control network based on the precision requirements of the construction layout of hub buildings.We quickly complete the field data collection of the control network by advanced measuring instruments，and use the measurement data of Guangxi continuous operating reference station(GXCORS) to centrally and uniformly process GNSS data，so as to efficiently complete the production processes of construction control network technology design，field data collection，internal data processing，accuracy analysis，and achievement provision.

Abstract:Gabion retaining wall is a flexible structure that is prone to deformation and excessive settlement during construction，resulting in flatness and elevation exceeding the acceptance standards.This paper uses the discrete element simulation software EDEM and finite element simulation software ANSYS to jointly simulate the force and deformation of the Gebin gabion itself and the internal granular system.The force on the gabion mesh box has the characteristics of complexity and randomness.This paper starts from studying the soil pressure of the gabion net box，and proposes a solution to the problem of excessive deformation of the gabion revetment wall by using material and stone masonry within a certain range in front of the gabion revetment wall.Regarding the issue of excessive settlement，measures such as reserving settlement or increasing the height of the cage are proposed，which have achieved significant results and can serve as a reference for similar projects in the future.

Abstract:Regarding the problems of difficult manual detection of slope and incomplete measurement data in the construction of high and steep slope sparing，an automatic detection method of airborne slope cutting quality is proposed.Firstly，the equation of the motion trajectory of the excavator tooth tip coordinates is established based on the Beidou positioning point，and the wear error of the excavator is corrected.Then the relationship between the spatial coordinate trajectory of the excavator's tooth tip and the slope characteristics is analyzed.Through the study of the recognition and acquisition algorithm of bucket tooth tip coordinate data，the purpose of indirectly expressing the slope quality by using the tooth coordinate is realized.The practice of engineering application proves that this method meets the requirements of slope cutting quality inspection accuracy，replaces manual measurement，and improves construction efficiency.