A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the deve...A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.展开更多
Accurate prediction of main-engine rotational speed(RPM)is pivotal for en-ergy-efficient ship operation and compliance with emerging carbon-intensity regulations.Existing approaches either rely on computationally inte...Accurate prediction of main-engine rotational speed(RPM)is pivotal for en-ergy-efficient ship operation and compliance with emerging carbon-intensity regulations.Existing approaches either rely on computationally intensive phys-ics-based models or data-driven methods that neglect hydrodynamic con-straints and suffer from label noise in mandatory reporting data.We propose a physics-informed LightGBM framework that fuses high-resolution AIS tra-jectories,meteorological re-analyses and EU MRV logs through a temporally anchored,multi-source alignment protocol.A dual LightGBM ensemble(L1/L2)predicts RPM under laden and ballast conditions.Validation on a Panamax tanker(366 days)yields−1.52 rpm(−3%)error;ballast accuracy surpasses laden by 1.7%.展开更多
The purpose of this study is to establish a multivariate nonlinear regression mathematical model to predict the displacement of tumor during brain tumor resection surgery.And the study will be integrated with augmente...The purpose of this study is to establish a multivariate nonlinear regression mathematical model to predict the displacement of tumor during brain tumor resection surgery.And the study will be integrated with augmented reality technology to achieve three-dimensional visualization,thereby enhancing the complete resection rate of tumor and the success rate of surgery.Based on the preoperative MRI data of the patients,a 3D virtual model is reconstructed and 3D printed.A brain biomimetic model is created using gel injection molding.By considering cerebrospinal fluid loss and tumor cyst fluid loss as independent variables,the highest point displacement in the vertical bone window direction is determined as the dependent variable after positioning the patient for surgery.An orthogonal experiment is conducted on the biomimetic model to establish a predictive model,and this model is incorporated into the augmented reality navigation system.To validate the predictive model,five participants wore HoloLens2 devices,overlaying the patient’s 3D virtual model onto the physical head model.Subsequently,the spatial coordinates of the tumor’s highest point after displacement were measured on both the physical and virtual models(actual coordinates and predicted coordinates,respectively).The difference between these coordinates represents the model’s prediction error.The results indicate that the measured and predicted errors for the displacement of the tumor’s highest point on the X and Y axes range from−0.6787 mm to 0.2957 mm and−0.4314 mm to 0.2253 mm,respectively.The relative errors for each experimental group are within 10%,demonstrating a good fit of the model.This method of establishing a regression model represents a preliminary attempt to predict brain tumor displacement in specific situations.It also provides a new approach for surgeons.By combining augmented reality visualization,it addresses the need for predicting tumor displacement and precisely locating brain anatomical structures in a simple and cost-effective manner.展开更多
Ongoing climate change has accelerated the outbreak and expansion of climate-sensitive infectious diseases such as dengue fever.Dengue fever will remain a threat until safe and effective vaccines and antiviral drugs h...Ongoing climate change has accelerated the outbreak and expansion of climate-sensitive infectious diseases such as dengue fever.Dengue fever will remain a threat until safe and effective vaccines and antiviral drugs have been developed,distributed,and administered on a global scale.By predicting the spatiotemporal distribution of dengue fever outbreaks,we can effectively implement dengue fever prevention and control.Our study aims to predict the spatiotemporal distribution of dengue fever outbreaks in Chinese Taiwan using a U-Net based encoder-decoder model with daily datasets of sea-surface temperature,rainfall,and shortwave radiation from Remote Sensing(RS)instruments and dengue fever case notification data.Although the prediction accuracy of the proposed model was low and the overlapping areas between the ground truth and pixelwise prediction were few,some of the pixels were located nearby the ground truth,suggesting that the application of RS data and deep learning may help to predict the spatiotemporal distribution of dengue fever outbreaks.With further improvements,the deep learning model might effectively learn a small amount of training data for a specific task.展开更多
Regional landslide susceptibility mapping(LSM)is essential for risk mitigation.While deep learning algorithms are increasingly used in LSM,their extensive parameters and scarce labels(limited landslide records)pose tr...Regional landslide susceptibility mapping(LSM)is essential for risk mitigation.While deep learning algorithms are increasingly used in LSM,their extensive parameters and scarce labels(limited landslide records)pose training challenges.In contrast,classical statistical algorithms,with typically fewer parameters,are less likely to overfit,easier to train,and offer greater interpretability.Additionally,integrating physics-based and data-driven approaches can potentially improve LSM.This paper makes several contributions to enhance the practicality,interpretability,and cross-regional generalization ability of regional LSM models:(1)Two new hybrid models,composed of data-driven and physics-based modules,are proposed and compared.Hybrid ModelⅠcombines the infinite slope stability analysis(ISSA)with logistic regression,a classical statistical algorithm.Hybrid ModelⅡintegrates ISSA with a convolutional neural network,a representative of deep learning techniques.The physics-based module constructs a new explanatory factor with higher nonlinearity and reduces prediction uncertainty caused by incomplete landslide inventory by pre-selecting non-landslide samples.The data-driven module captures the rela-tion between explanatory factors and landslide inventory.(2)A step-wise deletion process is proposed to assess the importance of explanatory factors and identify the minimum necessary factors required to maintain satisfactory model performance.(3)Single-pixel and local-area samples are compared to understand the effect of pixel spatial neighborhood.(4)The impact of nonlinearity in data-driven algorithms on hybrid model performance is explored.Typical landslide-prone regions in the Three Gorges Reservoir,China,are used as the study area.The results show that,in the testing region,by using local-area samples to account for pixel spatial neighborhoods,Hybrid ModelⅠachieves roughly a 4.2%increase in the AUC.Furthermore,models with 30 m resolution land-cover data surpass those using 1000 m resolution data,showing a 5.5%improvement in AUC.The optimal set of explanatory factors includes elevation,land-cover type,and safety factor.These findings reveal the key elements to enhance regional LSM,offering valuable insights for LSM practices.展开更多
Due to obvious advantages,such as light weight,easy folding and deployment and high accuracy of optical imaging,the membrane diffraction large space telescope has currently been one of the hot research topics.Because ...Due to obvious advantages,such as light weight,easy folding and deployment and high accuracy of optical imaging,the membrane diffraction large space telescope has currently been one of the hot research topics.Because of the influence of external disturbance and attitude adjustment,the large space telescope will occur a certain degree of vibration inevitably,affecting the imaging accuracy of the space telescope for Earth.Thus,to satisfy the requirement of imaging accuracy,it is necessary for the space telescope to adopt appropriate vibration control methods.In this paper,the active vibration control of the large space telescope is studied using cables as active actuators.Considering that cables can work under tension but not under pression and the tensile capacity is limited,the unilateral and saturated characteristics of cable actuators are taken into account during control design in this paper.Firstly,the dynamic model of the membrane diffraction space telescope is established using the finite element method(FEM).Secondly,in combination with the linear quadratic regulator(LQR)and the bang-bang regulator,a piecewise cost function is used to design the active vibration control law.Next,the controllability criterion and the genetic algorithm(GA)are adopted to determine the optimal positions of cable actuators.Finally,the validity of the proposed control method is verified by numerical simulations.Simulation results indicate that the vibration of the space telescope can be suppressed effectively using the proposed control method,and the imaging requirements of the telescope may be realized using the least cable actuators,whose minimum quantity and position distribution are determined in this paper.展开更多
Knowledge of pore-water pressure(PWP)variation is fundamental for slope stability.A precise prediction of PWP is difficult due to complex physical mechanisms and in situ natural variability.To explore the applicabilit...Knowledge of pore-water pressure(PWP)variation is fundamental for slope stability.A precise prediction of PWP is difficult due to complex physical mechanisms and in situ natural variability.To explore the applicability and advantages of recurrent neural networks(RNNs)on PWP prediction,three variants of RNNs,i.e.,standard RNN,long short-term memory(LSTM)and gated recurrent unit(GRU)are adopted and compared with a traditional static artificial neural network(ANN),i.e.,multi-layer perceptron(MLP).Measurements of rainfall and PWP of representative piezometers from a fully instrumented natural slope in Hong Kong are used to establish the prediction models.The coefficient of determination(R^2)and root mean square error(RMSE)are used for model evaluations.The influence of input time series length on the model performance is investigated.The results reveal that MLP can provide acceptable performance but is not robust.The uncertainty bounds of RMSE of the MLP model range from 0.24 kPa to 1.12 k Pa for the selected two piezometers.The standard RNN can perform better but the robustness is slightly affected when there are significant time lags between PWP changes and rainfall.The GRU and LSTM models can provide more precise and robust predictions than the standard RNN.The effects of the hidden layer structure and the dropout technique are investigated.The single-layer GRU is accurate enough for PWP prediction,whereas a double-layer GRU brings extra time cost with little accuracy improvement.The dropout technique is essential to overfitting prevention and improvement of accuracy.展开更多
A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different ...A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different complex nonsmooth/discontinuous interfaces, we develop an R(x)-orthonormal theory, where R(x) is an integrable flexural rigidity function. The R(x)-orthonormal bases in the linear space of boundary functions are constructed, of which the second-order derivatives of the boundary functions are asked to be orthonormal with respect to the weight function R(x). When the vibration modes of the symmetric composite beam are expressed in terms of the R(x)-orthonormal bases we can derive an eigenvalue problem endowed with a special structure of the coefficient matrix A :=[aij ],aij= 0 if i + j is odd. Based on the special structure we can prove two new theorems, which indicate that the characteristic equation of A can be decomposed into the product of the characteristic equations of two sub-matrices with dimensions half lower. Hence, we can sequentially solve the natural frequencies in closed-form owing to the specialty of A. We use this powerful new theory to analyze the free vibration performance and the vibration modes of symmetric composite beams with three different interfaces.展开更多
Metros are critical infrastructure in big cities and evaluation of their safe operation is of increasing im-portance.To make a reasonable safety evaluation for the metro during operation,this paper establishes a ratio...Metros are critical infrastructure in big cities and evaluation of their safe operation is of increasing im-portance.To make a reasonable safety evaluation for the metro during operation,this paper establishes a rational safety evaluation model based on long-term monitoring data of Shanghai Metro Line 2.Four evaluation indicators,ie.,absolute settlement,relative curvature,deformation rate and curvature radius,are adopted.Analytic hierar-chy process(AHP)and entropy method are combined to determine the weights of the indicators.The risk level values at different mileage are calculated and five danger levels are defined accordingly to determine the safety state of Shanghai Metro Line 2,ie.,safe,relatively safe,critical,relatively dangerous,and dangerous.Safety evaluation of Shanghai Metro Line 2 shows that:83.81%areas of Shanghai Metro Line 2 are in safe,relatively safe and critical states,while 15.63%and 0.57%areas are in relatively dangerous and dangerous states,respectively;the parts of Shanghai Metro Line 2 where the risk level values exceed the critical value are mainly distributed around the mileage at 6.0-7.5km and 8.5-11.0 km,and the risk level value peaks around the mileage at 7.3km,to which much attention should be attached and relevant protective measures be taken;the sections with the high risk level values coincide with the distinctly deforming arcas of the metro,indicating that this evaluation method is valid.展开更多
Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices'commercial applications.Therefore,the efficiency enhancement of wave energy converters has received much attention in recent ...Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices'commercial applications.Therefore,the efficiency enhancement of wave energy converters has received much attention in recent decades.The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter(WEC)to improve the energy absorption perfomance.The double snap-through mechanism comprises four oblique springs mounted in an X-configuration.This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed.The efficiency of these different WEC behaviors(linear,bistable,and tristable)was initially evaluated under the action of regular waves.The results for bistable or tristable responses indicated significant improvements in the WEC's energy capture efficiency.Furthermore,the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation.However,the corresponding tristable trajectory showed intra-well behavior in the middle potential well,which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed.Nevertheless,positive effects were observed when appropriate initial conditions were imposed.The results also showed that for bistable or tristable responses,a suitable spring stiffness may cause the buoy to oscillate in high energy modes.展开更多
The floating offshore wind turbine(FOWT) is widely used for harvesting marine wind energy. Its dynamic responses under offshore wind and wave environment provide essential reference for the design and installation. In...The floating offshore wind turbine(FOWT) is widely used for harvesting marine wind energy. Its dynamic responses under offshore wind and wave environment provide essential reference for the design and installation. In this study,the dynamic responses of a 6 MW Spar type FOWT designed for the water depth of 100 m are investigated by means of the wave tank experiment and numerical analysis. A scaled model is manufactured for the experiment at a ratio of65.3, while the numerical model is constructed on the open-source platform FAST(Fatigue, Aerodynamics,Structures, and Turbulence). Still water tests, wind-induced only tests, wave-induced only tests and combined windwave-current tests are all conducted experimentally and numerically. The accuracy of the experimental set-up as well as the loading generation has been verified. Surge, pitch and heave motions are selected to analyze and the numerical results agree well with the experimental values. Even though results obtained by using the FOWT calculation model established in FAST software show some deviations from the test results, the trends are always consistent. Both experimental and numerical studies demonstrate that they are reliable for the designed 6 MW Spar type FOWT.展开更多
Satellite remote sensing technique offers a wide range of information, and is one of the tools for ocean wave observation. This paper discusses the limitations of Synthetic Aperture Radar (SAR) images in wave field an...Satellite remote sensing technique offers a wide range of information, and is one of the tools for ocean wave observation. This paper discusses the limitations of Synthetic Aperture Radar (SAR) images in wave field analysis. It is found that the wave field analysis is affected by the gray value distribution of image and the relationship between satellite travel and wave propagation directions. Since human activities and coastal engineering are performed in nearshore areas, some issues are discussed for nearshore SAR image analysis. Several case studies show that the wave parameters estimated from nearshore SAR images are quite different from in situ measurements, suggesting that the wave information derived from nearshore SAR images cannot appropriately represent the wave characteristics. One of the reasons is that the wave field is non homogeneous in the nearshore area.展开更多
Soil spatial variability is difficult to evaluate due to insufficient test data.An alternative option is estimation by indirect methods such as inverse analysis.In this paper,two examples are presented to demonstrate ...Soil spatial variability is difficult to evaluate due to insufficient test data.An alternative option is estimation by indirect methods such as inverse analysis.In this paper,two examples are presented to demonstrate the capability and accuracy of the probabilistic estimation method to characterize soil spatial variability with displacement responses.The first example is a soil slope subject to a surcharge load,in which the spatially varied field of the elastic modulus is estimated with displacements.The results show that estimations based on horizontal displacements were more accurate than those based on vertical displacements.The accuracy of the estimated field was substantially reduced by increasing variance of elastic modulus.However,the estimation was generally acceptable as the error was not more than 10%,even for the high variance case(COV^l.5).The accuracy of estimation was also affected by the type of covariance function and the correlation length.When the correlation length decreased,the accuracy of estimation was reduced.The second example is a validation of laboratory model tests where a horizontal load was applied on a layered ground.The estimated thicknesses of soil layers were close to those in the real situation,which demonstrates the capacity of the estimation method.展开更多
The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the ...The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC.It also depends on the efficiency of the power take-off system(PTO).This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching.The PTO characteristics,such as the gear ratio,the flywheel inertia,and the electric generator,are analyzed in the WEC performance.Three cylindrical point absorbers are also considered in the present study.A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves.The wave energy converter(WEC)performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied.The latching control system increases the mean power.However,the increase is not significant if the parameters that characterize the WEC provide a considerable mean power.The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel.However,the gear ratio shows a more significant influence than the flywheel inertia.The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance.展开更多
Contrary to natural cavitation,ventilated cavitation is controllable and is not harmful.It is particularly used to reduce the drag of the hydraulic vehicles.The ventilated cavitation is characterized by various gas re...Contrary to natural cavitation,ventilated cavitation is controllable and is not harmful.It is particularly used to reduce the drag of the hydraulic vehicles.The ventilated cavitation is characterized by various gas regimes.The mechanisms of ventilated cavitation are investigated in the present work with CFD based on a 2D solver.The attention is especially focused on the transition between the reentrant jet and twin vortex regimes.The results confirmthat the product of ventilated cavitation number and Froude number is lower than 1(σcFr<1)in the twin vortex regime,while it is higher than 1(σcFr>1)in the reentrant jet regime,as reported in the literature.Further analysis shows that ventilated cavitation is significantly influenced by the natural cavitation number.展开更多
In practice,dewatering for pressure relief is commonly undertaken during ongoing excavation to secure bottom stability against basal upheaval.Simultaneously,through unloading,wall deflection is obviously observed.Noti...In practice,dewatering for pressure relief is commonly undertaken during ongoing excavation to secure bottom stability against basal upheaval.Simultaneously,through unloading,wall deflection is obviously observed.Noticing that both cause soil deformations,this research is to study the effect of wall deformation on dewateringinduced settlement.A coupled numerical analysis of finite-difference software is employed to model Shanghai soft soils under multi-aquifer-aquitard systems(MAASs)by analyzing the results in association with an empirical approach.Consequently,through gradual force reduction,shear strength at soil-wall interface is significantly diminished.As wall deformation increases instantaneously upon lower loading,wall surface becomes deformedly bending;this condition causes the challenge to workability of shear strength.Moreover,wall deformation caused by unloading affects dewatering-induced settlement substantially.Under smaller loading,large wall deflection is observed;soil plane of failure caused by both sliding and compression occurs along slip curve,with weaker shear-strength soils at rD=0.4 and stronger shear-strength soils between rD=0.4 and rD=0.65,where rD is the distance from the wall that is normalized by the depth measured from ground surface.During dewatering,stronger soils tend to drag weaker soils upward to reduce large differential settlements caused by additional compression.Consequently,settlement becomes larger at rD=0.4 and smaller at rD=0.65.Remarkably,at rD>2.3,both settlement curves that result from numerical analysis and empirical method show overlapping;this indicates that the unloading effect on dewatering-induced settlement at rD>2.3 is insignificant.Furthermore,as wall reaches maximum allowable wall deflection by 67%applied force,additional compression caused by dewatering after loading remains smaller than that under 70%applied force,contributing to smaller dewatering-induced settlement.展开更多
An experimental study is presented on the non-Gaussian statistics of random unidirectional laboratory wave fields described by JONSWAP spectra.Relationships between statistical parameters indicative of the occurrence ...An experimental study is presented on the non-Gaussian statistics of random unidirectional laboratory wave fields described by JONSWAP spectra.Relationships between statistical parameters indicative of the occurrence of largeamplitude waves are discussed in the context of the initial steepness of the waves combined with the effect of spectral peakedness.The spatial evolution of the relevant statistical and spectral parameters and features is also considered.It is demonstrated that over the distance the spectra exhibit features typical for developing nonlinear instabilities,such as spectral broadening and downshift of the peak,along with lowering of the high-frequency tail and decrease of the peak magnitude.The wave fields clearly show an increase of third-order nonlinearity with the distance,which can be significant,depending on the input wave environment.The steeper initial conditions,however,while favouring the occurrence of extremely large waves,also increase the chances of wave breaking and loss of energy due to dissipation,which results in lower extreme crests and wave heights.The applied Miche-Stokes-type criteria do confirm that some of the wave extremes exceed the limiting individual steepness.Eventually,this result agrees with the observation that the largest number of abnormal waves is recorded in sea states with moderate steepness.展开更多
The lining of shield tunnel is usually composed of segments,in which the joints,cracks,and the grouting holes(hereafter called lining deficit)exist.During the long-term running,soils and groundwater may leak from thes...The lining of shield tunnel is usually composed of segments,in which the joints,cracks,and the grouting holes(hereafter called lining deficit)exist.During the long-term running,soils and groundwater may leak from these kinds of lining deficit.The leaking of soil and groundwater causes the long-term ground loss around tunnel and thus results in the settlement of ground surface.This paper aims to analyze the impact of the leakage of groundwater through segments on the long-term settlement of ground surface.The adopted analytical method is based on the theory of groundwater seepage by using numerical simulation.The analyzed results show that settlement of ground surface increases gradually with the increase of the leaked volume of tunnel segments.When the leaked volume was unevenly distributed,differential settlement occurred locally.Comparative analysis by changing the leaked volume was conducted.The results reveal that there is a linear relationship between settlement and leaked volume when the leaked volume was controlled within the allowable limit.展开更多
This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of sever...This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of several brush seals at the tail of the shield.Four different failure modes for the multilayer seal system are discussed.A simple structural analysis of the brush seals is then conducted,and failure mode 4(failure due to brush seal deformation)is identified as a major reason for the Foshan tunnel accident.A finite element method(FEM)analysis is employed to validate the conclusions drawn from the simple structural analysis of the brush seals.展开更多
Existing solutions for axisymmetric active earth pressure are based on certain hypotheses of the circumferential stress, lacking of strict basis. This article presents a technique for deriving the actual circumferenti...Existing solutions for axisymmetric active earth pressure are based on certain hypotheses of the circumferential stress, lacking of strict basis. This article presents a technique for deriving the actual circumferential stress according to the circumferential geometric condition, the Drucker-Prager criterion and incremental theory. Based on the actual circumferential stress, a new characteristics method for determining the axisymmetric active earth pressure in plastic flow is developed in this article. In this new method, the inclined angle of boundaries, interface friction of contact interface, dilatation effect and flow velocity of soil are considered at the same time. The validity of the new method is confirmed using several sets of experimental data from the literature. The pressure coefficients are investigated individually in detail, and some different conclusions are found. Finally, a practical formula for calculating axisymmetric active earth pressure is presented based on the linear superposition principle, and related tables of coefficients are also provided for engineering application.展开更多
基金financially supported by the Science and Technology Commission Foundation of Shanghai(Grant Nos.22DZ1208903,20DZ2251900)the National Natural Science Foundation of China(Grant No.51679134)。
文摘A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.
基金support from the“Ocean-going Vessel Meteorological Navigation System”project funded under the Key Core Technology Breakthrough Program for Transportation Equipment(GJ-2025-01)COSCO Shipping Group’s Third Batch of Scientific Research Projects from the 14th Five-Year Plan.
文摘Accurate prediction of main-engine rotational speed(RPM)is pivotal for en-ergy-efficient ship operation and compliance with emerging carbon-intensity regulations.Existing approaches either rely on computationally intensive phys-ics-based models or data-driven methods that neglect hydrodynamic con-straints and suffer from label noise in mandatory reporting data.We propose a physics-informed LightGBM framework that fuses high-resolution AIS tra-jectories,meteorological re-analyses and EU MRV logs through a temporally anchored,multi-source alignment protocol.A dual LightGBM ensemble(L1/L2)predicts RPM under laden and ballast conditions.Validation on a Panamax tanker(366 days)yields−1.52 rpm(−3%)error;ballast accuracy surpasses laden by 1.7%.
基金the University of Shanghai for Science and Technology’s Medical Engineering Interdisciplinary Project(No.10-22-308-520)the Ministry of Education’s First Batch of Industry-Education Cooperation Collaborative Education Projects(No.202101042008)+1 种基金the Fundamental Research Funds for the Central Universities(No.YG2019QNA34)the Shanghai Municipal Health Commission for Youth Clinical Research Project(No.20194Y0134)。
文摘The purpose of this study is to establish a multivariate nonlinear regression mathematical model to predict the displacement of tumor during brain tumor resection surgery.And the study will be integrated with augmented reality technology to achieve three-dimensional visualization,thereby enhancing the complete resection rate of tumor and the success rate of surgery.Based on the preoperative MRI data of the patients,a 3D virtual model is reconstructed and 3D printed.A brain biomimetic model is created using gel injection molding.By considering cerebrospinal fluid loss and tumor cyst fluid loss as independent variables,the highest point displacement in the vertical bone window direction is determined as the dependent variable after positioning the patient for surgery.An orthogonal experiment is conducted on the biomimetic model to establish a predictive model,and this model is incorporated into the augmented reality navigation system.To validate the predictive model,five participants wore HoloLens2 devices,overlaying the patient’s 3D virtual model onto the physical head model.Subsequently,the spatial coordinates of the tumor’s highest point after displacement were measured on both the physical and virtual models(actual coordinates and predicted coordinates,respectively).The difference between these coordinates represents the model’s prediction error.The results indicate that the measured and predicted errors for the displacement of the tumor’s highest point on the X and Y axes range from−0.6787 mm to 0.2957 mm and−0.4314 mm to 0.2253 mm,respectively.The relative errors for each experimental group are within 10%,demonstrating a good fit of the model.This method of establishing a regression model represents a preliminary attempt to predict brain tumor displacement in specific situations.It also provides a new approach for surgeons.By combining augmented reality visualization,it addresses the need for predicting tumor displacement and precisely locating brain anatomical structures in a simple and cost-effective manner.
基金supported by Japan Aerospace Exploration Agency[Grant No.RA1R803]the Collaboration Research Program of IDEAS,Chubu University[Grant No.IDEAS202008]。
文摘Ongoing climate change has accelerated the outbreak and expansion of climate-sensitive infectious diseases such as dengue fever.Dengue fever will remain a threat until safe and effective vaccines and antiviral drugs have been developed,distributed,and administered on a global scale.By predicting the spatiotemporal distribution of dengue fever outbreaks,we can effectively implement dengue fever prevention and control.Our study aims to predict the spatiotemporal distribution of dengue fever outbreaks in Chinese Taiwan using a U-Net based encoder-decoder model with daily datasets of sea-surface temperature,rainfall,and shortwave radiation from Remote Sensing(RS)instruments and dengue fever case notification data.Although the prediction accuracy of the proposed model was low and the overlapping areas between the ground truth and pixelwise prediction were few,some of the pixels were located nearby the ground truth,suggesting that the application of RS data and deep learning may help to predict the spatiotemporal distribution of dengue fever outbreaks.With further improvements,the deep learning model might effectively learn a small amount of training data for a specific task.
基金supported by the National Natural Science Foundation of China(Project Nos.52025094,51979158)support from Shanghai Municipal Education Commission(Project No.2021-01-07-00-02-E00089).
文摘Regional landslide susceptibility mapping(LSM)is essential for risk mitigation.While deep learning algorithms are increasingly used in LSM,their extensive parameters and scarce labels(limited landslide records)pose training challenges.In contrast,classical statistical algorithms,with typically fewer parameters,are less likely to overfit,easier to train,and offer greater interpretability.Additionally,integrating physics-based and data-driven approaches can potentially improve LSM.This paper makes several contributions to enhance the practicality,interpretability,and cross-regional generalization ability of regional LSM models:(1)Two new hybrid models,composed of data-driven and physics-based modules,are proposed and compared.Hybrid ModelⅠcombines the infinite slope stability analysis(ISSA)with logistic regression,a classical statistical algorithm.Hybrid ModelⅡintegrates ISSA with a convolutional neural network,a representative of deep learning techniques.The physics-based module constructs a new explanatory factor with higher nonlinearity and reduces prediction uncertainty caused by incomplete landslide inventory by pre-selecting non-landslide samples.The data-driven module captures the rela-tion between explanatory factors and landslide inventory.(2)A step-wise deletion process is proposed to assess the importance of explanatory factors and identify the minimum necessary factors required to maintain satisfactory model performance.(3)Single-pixel and local-area samples are compared to understand the effect of pixel spatial neighborhood.(4)The impact of nonlinearity in data-driven algorithms on hybrid model performance is explored.Typical landslide-prone regions in the Three Gorges Reservoir,China,are used as the study area.The results show that,in the testing region,by using local-area samples to account for pixel spatial neighborhoods,Hybrid ModelⅠachieves roughly a 4.2%increase in the AUC.Furthermore,models with 30 m resolution land-cover data surpass those using 1000 m resolution data,showing a 5.5%improvement in AUC.The optimal set of explanatory factors includes elevation,land-cover type,and safety factor.These findings reveal the key elements to enhance regional LSM,offering valuable insights for LSM practices.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.12172214 and 12102252)the China Postdoctoral Science Foundation(Grant No.2021M692070)the Industry-University-Research Cooperation Fund of Shanghai Institute of Aerospace System Engineering(Grant No.USCAST2021-12).
文摘Due to obvious advantages,such as light weight,easy folding and deployment and high accuracy of optical imaging,the membrane diffraction large space telescope has currently been one of the hot research topics.Because of the influence of external disturbance and attitude adjustment,the large space telescope will occur a certain degree of vibration inevitably,affecting the imaging accuracy of the space telescope for Earth.Thus,to satisfy the requirement of imaging accuracy,it is necessary for the space telescope to adopt appropriate vibration control methods.In this paper,the active vibration control of the large space telescope is studied using cables as active actuators.Considering that cables can work under tension but not under pression and the tensile capacity is limited,the unilateral and saturated characteristics of cable actuators are taken into account during control design in this paper.Firstly,the dynamic model of the membrane diffraction space telescope is established using the finite element method(FEM).Secondly,in combination with the linear quadratic regulator(LQR)and the bang-bang regulator,a piecewise cost function is used to design the active vibration control law.Next,the controllability criterion and the genetic algorithm(GA)are adopted to determine the optimal positions of cable actuators.Finally,the validity of the proposed control method is verified by numerical simulations.Simulation results indicate that the vibration of the space telescope can be suppressed effectively using the proposed control method,and the imaging requirements of the telescope may be realized using the least cable actuators,whose minimum quantity and position distribution are determined in this paper.
基金supported by the Natural Science Foundation of China(Grant Nos.51979158,51639008,51679135,and 51422905)the Program of Shanghai Academic Research Leader by Science and Technology Commission of Shanghai Municipality(Project No.19XD1421900)。
文摘Knowledge of pore-water pressure(PWP)variation is fundamental for slope stability.A precise prediction of PWP is difficult due to complex physical mechanisms and in situ natural variability.To explore the applicability and advantages of recurrent neural networks(RNNs)on PWP prediction,three variants of RNNs,i.e.,standard RNN,long short-term memory(LSTM)and gated recurrent unit(GRU)are adopted and compared with a traditional static artificial neural network(ANN),i.e.,multi-layer perceptron(MLP).Measurements of rainfall and PWP of representative piezometers from a fully instrumented natural slope in Hong Kong are used to establish the prediction models.The coefficient of determination(R^2)and root mean square error(RMSE)are used for model evaluations.The influence of input time series length on the model performance is investigated.The results reveal that MLP can provide acceptable performance but is not robust.The uncertainty bounds of RMSE of the MLP model range from 0.24 kPa to 1.12 k Pa for the selected two piezometers.The standard RNN can perform better but the robustness is slightly affected when there are significant time lags between PWP changes and rainfall.The GRU and LSTM models can provide more precise and robust predictions than the standard RNN.The effects of the hidden layer structure and the dropout technique are investigated.The single-layer GRU is accurate enough for PWP prediction,whereas a double-layer GRU brings extra time cost with little accuracy improvement.The dropout technique is essential to overfitting prevention and improvement of accuracy.
文摘A composite beam is symmetric if both the material property and support are symmetric with respect to the middle point. In order to study the free vibration performance of the symmetric composite beams with different complex nonsmooth/discontinuous interfaces, we develop an R(x)-orthonormal theory, where R(x) is an integrable flexural rigidity function. The R(x)-orthonormal bases in the linear space of boundary functions are constructed, of which the second-order derivatives of the boundary functions are asked to be orthonormal with respect to the weight function R(x). When the vibration modes of the symmetric composite beam are expressed in terms of the R(x)-orthonormal bases we can derive an eigenvalue problem endowed with a special structure of the coefficient matrix A :=[aij ],aij= 0 if i + j is odd. Based on the special structure we can prove two new theorems, which indicate that the characteristic equation of A can be decomposed into the product of the characteristic equations of two sub-matrices with dimensions half lower. Hence, we can sequentially solve the natural frequencies in closed-form owing to the specialty of A. We use this powerful new theory to analyze the free vibration performance and the vibration modes of symmetric composite beams with three different interfaces.
基金the National Natural Science Founda-tion of China(Nos.41602283 and 41977216)the Science and Technology Rising-Star Program of Shang-hai(No.19QC1400800)。
文摘Metros are critical infrastructure in big cities and evaluation of their safe operation is of increasing im-portance.To make a reasonable safety evaluation for the metro during operation,this paper establishes a rational safety evaluation model based on long-term monitoring data of Shanghai Metro Line 2.Four evaluation indicators,ie.,absolute settlement,relative curvature,deformation rate and curvature radius,are adopted.Analytic hierar-chy process(AHP)and entropy method are combined to determine the weights of the indicators.The risk level values at different mileage are calculated and five danger levels are defined accordingly to determine the safety state of Shanghai Metro Line 2,ie.,safe,relatively safe,critical,relatively dangerous,and dangerous.Safety evaluation of Shanghai Metro Line 2 shows that:83.81%areas of Shanghai Metro Line 2 are in safe,relatively safe and critical states,while 15.63%and 0.57%areas are in relatively dangerous and dangerous states,respectively;the parts of Shanghai Metro Line 2 where the risk level values exceed the critical value are mainly distributed around the mileage at 6.0-7.5km and 8.5-11.0 km,and the risk level value peaks around the mileage at 7.3km,to which much attention should be attached and relevant protective measures be taken;the sections with the high risk level values coincide with the distinctly deforming arcas of the metro,indicating that this evaluation method is valid.
基金supported by the China Scholarship Council under Grant No.201600090258the National Key Research and Development Program of China under Grant No.2016YFC0303700the 111 Project under Grant No.B18054。
文摘Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices'commercial applications.Therefore,the efficiency enhancement of wave energy converters has received much attention in recent decades.The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter(WEC)to improve the energy absorption perfomance.The double snap-through mechanism comprises four oblique springs mounted in an X-configuration.This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed.The efficiency of these different WEC behaviors(linear,bistable,and tristable)was initially evaluated under the action of regular waves.The results for bistable or tristable responses indicated significant improvements in the WEC's energy capture efficiency.Furthermore,the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation.However,the corresponding tristable trajectory showed intra-well behavior in the middle potential well,which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed.Nevertheless,positive effects were observed when appropriate initial conditions were imposed.The results also showed that for bistable or tristable responses,a suitable spring stiffness may cause the buoy to oscillate in high energy modes.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51809170 and 51879160)the National Key R&D Program of China (Grant No. 2019YFB1503700)+1 种基金Program for Intergovernmental International S&T Cooperation Projects of Shanghai Municipality (Grant Nos.19160713600 and 18160744000)the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (Grant Nos. ZXDF010037 and ZXDF010040)。
文摘The floating offshore wind turbine(FOWT) is widely used for harvesting marine wind energy. Its dynamic responses under offshore wind and wave environment provide essential reference for the design and installation. In this study,the dynamic responses of a 6 MW Spar type FOWT designed for the water depth of 100 m are investigated by means of the wave tank experiment and numerical analysis. A scaled model is manufactured for the experiment at a ratio of65.3, while the numerical model is constructed on the open-source platform FAST(Fatigue, Aerodynamics,Structures, and Turbulence). Still water tests, wind-induced only tests, wave-induced only tests and combined windwave-current tests are all conducted experimentally and numerically. The accuracy of the experimental set-up as well as the loading generation has been verified. Surge, pitch and heave motions are selected to analyze and the numerical results agree well with the experimental values. Even though results obtained by using the FOWT calculation model established in FAST software show some deviations from the test results, the trends are always consistent. Both experimental and numerical studies demonstrate that they are reliable for the designed 6 MW Spar type FOWT.
文摘Satellite remote sensing technique offers a wide range of information, and is one of the tools for ocean wave observation. This paper discusses the limitations of Synthetic Aperture Radar (SAR) images in wave field analysis. It is found that the wave field analysis is affected by the gray value distribution of image and the relationship between satellite travel and wave propagation directions. Since human activities and coastal engineering are performed in nearshore areas, some issues are discussed for nearshore SAR image analysis. Several case studies show that the wave parameters estimated from nearshore SAR images are quite different from in situ measurements, suggesting that the wave information derived from nearshore SAR images cannot appropriately represent the wave characteristics. One of the reasons is that the wave field is non homogeneous in the nearshore area.
基金the National Natural Science Foundation of China(Nos.51979158,51639008,51679135,and 51422905)the Program of Shanghai Academic Research Leader(No.19XD1421900),China。
文摘Soil spatial variability is difficult to evaluate due to insufficient test data.An alternative option is estimation by indirect methods such as inverse analysis.In this paper,two examples are presented to demonstrate the capability and accuracy of the probabilistic estimation method to characterize soil spatial variability with displacement responses.The first example is a soil slope subject to a surcharge load,in which the spatially varied field of the elastic modulus is estimated with displacements.The results show that estimations based on horizontal displacements were more accurate than those based on vertical displacements.The accuracy of the estimated field was substantially reduced by increasing variance of elastic modulus.However,the estimation was generally acceptable as the error was not more than 10%,even for the high variance case(COV^l.5).The accuracy of estimation was also affected by the type of covariance function and the correlation length.When the correlation length decreased,the accuracy of estimation was reduced.The second example is a validation of laboratory model tests where a horizontal load was applied on a layered ground.The estimated thicknesses of soil layers were close to those in the real situation,which demonstrates the capacity of the estimation method.
基金The authors acknowledge the support from the Brazilian Research Council(CNPq),contract numbers 380950/2018-9(INEOF-National Institute for Ocean and River Energy)and 305657/2017-8,respectivelySpecial thanks to FAPERJ for the support of the wave energy research at the Subsea Technology Lab(COPPE),contract number E-26/202.600/2019。
文摘The latching control represents an attractive alternative to increase the power absorption of wave energy converters(WECs)by tuning the phase of oscillator velocity to the wave excitation phase.However,increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC.It also depends on the efficiency of the power take-off system(PTO).This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching.The PTO characteristics,such as the gear ratio,the flywheel inertia,and the electric generator,are analyzed in the WEC performance.Three cylindrical point absorbers are also considered in the present study.A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves.The wave energy converter(WEC)performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied.The latching control system increases the mean power.However,the increase is not significant if the parameters that characterize the WEC provide a considerable mean power.The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel.However,the gear ratio shows a more significant influence than the flywheel inertia.The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance.
基金performed in the scope of project ANR-12-ASTR-0017-03 "BF-DRAINH" in collaboration with the IRENav Laboratory (French Naval Academy,Brest,France) and the IMFT laboratory (Toulouse,France)
文摘Contrary to natural cavitation,ventilated cavitation is controllable and is not harmful.It is particularly used to reduce the drag of the hydraulic vehicles.The ventilated cavitation is characterized by various gas regimes.The mechanisms of ventilated cavitation are investigated in the present work with CFD based on a 2D solver.The attention is especially focused on the transition between the reentrant jet and twin vortex regimes.The results confirmthat the product of ventilated cavitation number and Froude number is lower than 1(σcFr<1)in the twin vortex regime,while it is higher than 1(σcFr>1)in the reentrant jet regime,as reported in the literature.Further analysis shows that ventilated cavitation is significantly influenced by the natural cavitation number.
基金the National Natural Science Founda-tion of China(Nos.41727802,41977216 and 41602283)。
文摘In practice,dewatering for pressure relief is commonly undertaken during ongoing excavation to secure bottom stability against basal upheaval.Simultaneously,through unloading,wall deflection is obviously observed.Noticing that both cause soil deformations,this research is to study the effect of wall deformation on dewateringinduced settlement.A coupled numerical analysis of finite-difference software is employed to model Shanghai soft soils under multi-aquifer-aquitard systems(MAASs)by analyzing the results in association with an empirical approach.Consequently,through gradual force reduction,shear strength at soil-wall interface is significantly diminished.As wall deformation increases instantaneously upon lower loading,wall surface becomes deformedly bending;this condition causes the challenge to workability of shear strength.Moreover,wall deformation caused by unloading affects dewatering-induced settlement substantially.Under smaller loading,large wall deflection is observed;soil plane of failure caused by both sliding and compression occurs along slip curve,with weaker shear-strength soils at rD=0.4 and stronger shear-strength soils between rD=0.4 and rD=0.65,where rD is the distance from the wall that is normalized by the depth measured from ground surface.During dewatering,stronger soils tend to drag weaker soils upward to reduce large differential settlements caused by additional compression.Consequently,settlement becomes larger at rD=0.4 and smaller at rD=0.65.Remarkably,at rD>2.3,both settlement curves that result from numerical analysis and empirical method show overlapping;this indicates that the unloading effect on dewatering-induced settlement at rD>2.3 is insignificant.Furthermore,as wall reaches maximum allowable wall deflection by 67%applied force,additional compression caused by dewatering after loading remains smaller than that under 70%applied force,contributing to smaller dewatering-induced settlement.
基金the Portuguese Foundation for Science and Technology (Fundação para a Ciência e Tecnologia-FCT) under contract UIDB/UIDP/00134/2020The experiments at Lab Oceano were supported by the National Petroleum Agency of Brazil (ANP)
文摘An experimental study is presented on the non-Gaussian statistics of random unidirectional laboratory wave fields described by JONSWAP spectra.Relationships between statistical parameters indicative of the occurrence of largeamplitude waves are discussed in the context of the initial steepness of the waves combined with the effect of spectral peakedness.The spatial evolution of the relevant statistical and spectral parameters and features is also considered.It is demonstrated that over the distance the spectra exhibit features typical for developing nonlinear instabilities,such as spectral broadening and downshift of the peak,along with lowering of the high-frequency tail and decrease of the peak magnitude.The wave fields clearly show an increase of third-order nonlinearity with the distance,which can be significant,depending on the input wave environment.The steeper initial conditions,however,while favouring the occurrence of extremely large waves,also increase the chances of wave breaking and loss of energy due to dissipation,which results in lower extreme crests and wave heights.The applied Miche-Stokes-type criteria do confirm that some of the wave extremes exceed the limiting individual steepness.Eventually,this result agrees with the observation that the largest number of abnormal waves is recorded in sea states with moderate steepness.
基金supported by the National Natural Science Foundation of China(Grant No.41072209)the joint research program between NSFC and the Japan Society for the Promotion of Science(50911140105)+1 种基金Shanghai Leading Academic Discipline Project(Project Number:B208)the Innovative Self-selected Project of the State Key Laboratory of Ocean Engineering(GKZD010051).
文摘The lining of shield tunnel is usually composed of segments,in which the joints,cracks,and the grouting holes(hereafter called lining deficit)exist.During the long-term running,soils and groundwater may leak from these kinds of lining deficit.The leaking of soil and groundwater causes the long-term ground loss around tunnel and thus results in the settlement of ground surface.This paper aims to analyze the impact of the leakage of groundwater through segments on the long-term settlement of ground surface.The adopted analytical method is based on the theory of groundwater seepage by using numerical simulation.The analyzed results show that settlement of ground surface increases gradually with the increase of the leaked volume of tunnel segments.When the leaked volume was unevenly distributed,differential settlement occurred locally.Comparative analysis by changing the leaked volume was conducted.The results reveal that there is a linear relationship between settlement and leaked volume when the leaked volume was controlled within the allowable limit.
基金The research work described herein was funded by the National Basic Research Program of China(973 Program:2015CB057806).This financial support is gratefully acknowledged.
文摘This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of several brush seals at the tail of the shield.Four different failure modes for the multilayer seal system are discussed.A simple structural analysis of the brush seals is then conducted,and failure mode 4(failure due to brush seal deformation)is identified as a major reason for the Foshan tunnel accident.A finite element method(FEM)analysis is employed to validate the conclusions drawn from the simple structural analysis of the brush seals.
基金supported by the National Natural Science Foundation of China(Grant No.51678360)the Shanghai Science and Technology Commission Project(Grant No.19QC1400800)the National Basic Research Program of China(Grant No.2014CB046302)。
文摘Existing solutions for axisymmetric active earth pressure are based on certain hypotheses of the circumferential stress, lacking of strict basis. This article presents a technique for deriving the actual circumferential stress according to the circumferential geometric condition, the Drucker-Prager criterion and incremental theory. Based on the actual circumferential stress, a new characteristics method for determining the axisymmetric active earth pressure in plastic flow is developed in this article. In this new method, the inclined angle of boundaries, interface friction of contact interface, dilatation effect and flow velocity of soil are considered at the same time. The validity of the new method is confirmed using several sets of experimental data from the literature. The pressure coefficients are investigated individually in detail, and some different conclusions are found. Finally, a practical formula for calculating axisymmetric active earth pressure is presented based on the linear superposition principle, and related tables of coefficients are also provided for engineering application.
