Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered so...Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.展开更多
The scaled suction caisson repre sents an innovative design featuring a bio-inspired sidewall modeled after snake skin,commonly utilized in offshore mooring platforms.In comparison with traditional suction caissons,th...The scaled suction caisson repre sents an innovative design featuring a bio-inspired sidewall modeled after snake skin,commonly utilized in offshore mooring platforms.In comparison with traditional suction caissons,this bio-inspired design demonstrates reduced penetration resistance and enhanced pull-out capacity due to the anisotropic shear behaviors of its sidewall.To investigate the shear behavior of the bio-inspired sidewall under pull-out load,direct shear tests were conducted between the bio-inspired surface and sand.The research demonstrates that the interface shear strength of the bio-inspired surface significantly surpasses that of the smooth surface due to interlocking effects.Additionally,the interface shear strength correlates with the aspect ratio of the bio-inspired surface,shear angle,and particle diameter distribution,with values increasing as the uniformity coefficient Cudecreases,while initially increasing and subsequently decreasing with increases in both aspect ratio and shear angle.The ratio between the interface friction angleδand internal friction angle δ_(s) defines the interface effect factor k.For the bio-inspired surface,the interface effect factor k varies with shear angleβ,ranging from 0.9 to 1.12.The peak value occurs at a shear angleβof 60°,substantially exceeding that of the smooth surface.A method for calculating the relative roughness R_(N) is employed to evaluate the interface roughness of the bio-inspired surface,taking into account scale dimension and particle diameter distribution effects.展开更多
Climate change is having an increasing impact on coastal infrastructure,leading to more frequent and intensified wave activity,including higher waves driven by typhoons and abnormal sea conditions.Consequently,issues ...Climate change is having an increasing impact on coastal infrastructure,leading to more frequent and intensified wave activity,including higher waves driven by typhoons and abnormal sea conditions.Consequently,issues related to the stability of existing port structures,such as caissons,have become a significant concern.In particular,gravity-type caisson on the land side of coastal port structures require enhanced stability and safety.Gravity-type caissons,which resist external forces through their own weight,are highly vulnerable to functional failures,such as sliding displacement,triggered by abnormal waves shifting specific caissons.The destruction of caisson and quay walls can lead to substantial recovery costs,necessitating improvements in caisson stability to address the challenges posed by increased wave forces and changes in port logistics due to larger vessels.One approach to enhancing caisson stability is the use of long caissons.Long caisson is commonly used where a breakwater is needed to withstand wave action and distribute forces evenly along a length of breakwater.The construction of caissons faces challenges due to limitations on the size of individual units imposed by construction conditions,launching methods,and marine crane requirements.Therefore,connecting multiple caissons to form long caissons presents a viable alternative.This study suggested two connection methods for long caissons.The first method was a hemisphere caisson,which allows the connection parts to seat against each other under self-weight during construction.The second method was a displacement-allowing connection utilizing rubble(embedded rebar connection within riprap connection).This approach allows some displacement while employing rebar to resist excessive deformation,thereby dispersing the resulting wave forces to adjacent caissons.Performance comparisons between the developed connections and conventional gravity-type caissons were conducted using a finite element analysis model.The results indicate that the proposed connections demonstrate improved resistance to wave forces compared to traditional caissons without such connections.Further studies should include field applications and performance evaluations of various caisson sizes under different environmental and geological conditions.展开更多
当前电力营销业务已由单一的供电服务逐渐转变为碳交易、客户侧储能、多能供应、能效服务、分布式电源等综合能源服务,及时响应用户需求变得尤为重要。针对传统建设模式中存在的跨环节协作壁垒、业务需求响应不及时等问题,文章借鉴中台...当前电力营销业务已由单一的供电服务逐渐转变为碳交易、客户侧储能、多能供应、能效服务、分布式电源等综合能源服务,及时响应用户需求变得尤为重要。针对传统建设模式中存在的跨环节协作壁垒、业务需求响应不及时等问题,文章借鉴中台架构设计理念,首先提出一种公共共享服务研运一体化支撑平台(middle-platform service components,MSC),利用模型编排、服务编排、流程编排、界面编排进行微服务灵活实现及扩展;然后,结合架构资产统一管理以及MSC四编排引擎,基于多租户技术进行电力营销业务系统研运一体化建设;最后,通过在客户侧工单中心建设中的应用,证明该模式可为电力营销业务系统建设提供有效支撑。展开更多
A suction caisson can be extracted by applying reverse pumping water,which cannot be regarded as the reverse process of installation because of the dramatically different soil−structure interaction behavior.Model test...A suction caisson can be extracted by applying reverse pumping water,which cannot be regarded as the reverse process of installation because of the dramatically different soil−structure interaction behavior.Model tests were first carried out in this study to investigate the extraction behavior of the modified suction caisson(MSC)and the regular suction caisson(RSC)in sand by reverse pumping water.The effects of the installation ways(suction-assisted or jacking installation)and the reverse pumping rate on the variations of the over-pressure resulting form reverse pumping water were investigated.It was found that neither the RSC nor the MSC can be fully extracted from sand.When the maximum extraction displacement is obtained,the hydraulic gradient of the sand in the suction caisson reaches the critical value,leading to seepage failure.In addition,the maximum extraction displacement decreases with the increasing reverse pumping rate.Under the same reverse pumping rate,the final extraction displacements for the RSC and MSC installed by suction are lower than those for the RSC and MSC installed by jacking.The final extraction displacement of MSC is almost equal to that of the RSC with the same internal compartment length.Based on the force equilibrium,a method of estimating the maximum extraction displacement is proposed.It has been proved that the proposed method can rationally predict the maximum extraction displacement and the corresponding over-pressure.展开更多
The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC)...The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC). The MSC can provide larger lateral bearing capacity and limit the deflection compared with the RSC. Therefore, the MSC can be much more appropriate to use as an offshore wind turbine foundation. Model tests on the MSC in saturated sand subjected to monotonic lateral loading were carried out to investigate the effects of external structure sizes on the sand surface deformation and the earth pressure distribution along the embedded depth. Test results show that the deformation range of the sand surface increases with the increasing width and length of the external structure. The magnitude of sand upheaval around the MSC is smaller than that of the RSC and the sand upheaval value around the MSC in the loading direction decreases with the increasing external structure dimensions. The net earth pressure in the loading direction acting on the internal compartment of the MSC is smaller than that of the RSC at the same embedded depth. The maximum net earth pressure acting on the external structure outer wall in the loading direction is larger than that of the internal compartment, indicating that a considerable amount of the lateral load and moment is resisted by the external skirt structure.展开更多
文摘Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.
基金supported by the National Natural Science Foundation of China(Grant Nos.52371301 and 52471289)。
文摘The scaled suction caisson repre sents an innovative design featuring a bio-inspired sidewall modeled after snake skin,commonly utilized in offshore mooring platforms.In comparison with traditional suction caissons,this bio-inspired design demonstrates reduced penetration resistance and enhanced pull-out capacity due to the anisotropic shear behaviors of its sidewall.To investigate the shear behavior of the bio-inspired sidewall under pull-out load,direct shear tests were conducted between the bio-inspired surface and sand.The research demonstrates that the interface shear strength of the bio-inspired surface significantly surpasses that of the smooth surface due to interlocking effects.Additionally,the interface shear strength correlates with the aspect ratio of the bio-inspired surface,shear angle,and particle diameter distribution,with values increasing as the uniformity coefficient Cudecreases,while initially increasing and subsequently decreasing with increases in both aspect ratio and shear angle.The ratio between the interface friction angleδand internal friction angle δ_(s) defines the interface effect factor k.For the bio-inspired surface,the interface effect factor k varies with shear angleβ,ranging from 0.9 to 1.12.The peak value occurs at a shear angleβof 60°,substantially exceeding that of the smooth surface.A method for calculating the relative roughness R_(N) is employed to evaluate the interface roughness of the bio-inspired surface,taking into account scale dimension and particle diameter distribution effects.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(Nos.RS-2023-00212586 and RS-2024-00348557)the Korea Maritime&Ocean University Research Fund in 2024.
文摘Climate change is having an increasing impact on coastal infrastructure,leading to more frequent and intensified wave activity,including higher waves driven by typhoons and abnormal sea conditions.Consequently,issues related to the stability of existing port structures,such as caissons,have become a significant concern.In particular,gravity-type caisson on the land side of coastal port structures require enhanced stability and safety.Gravity-type caissons,which resist external forces through their own weight,are highly vulnerable to functional failures,such as sliding displacement,triggered by abnormal waves shifting specific caissons.The destruction of caisson and quay walls can lead to substantial recovery costs,necessitating improvements in caisson stability to address the challenges posed by increased wave forces and changes in port logistics due to larger vessels.One approach to enhancing caisson stability is the use of long caissons.Long caisson is commonly used where a breakwater is needed to withstand wave action and distribute forces evenly along a length of breakwater.The construction of caissons faces challenges due to limitations on the size of individual units imposed by construction conditions,launching methods,and marine crane requirements.Therefore,connecting multiple caissons to form long caissons presents a viable alternative.This study suggested two connection methods for long caissons.The first method was a hemisphere caisson,which allows the connection parts to seat against each other under self-weight during construction.The second method was a displacement-allowing connection utilizing rubble(embedded rebar connection within riprap connection).This approach allows some displacement while employing rebar to resist excessive deformation,thereby dispersing the resulting wave forces to adjacent caissons.Performance comparisons between the developed connections and conventional gravity-type caissons were conducted using a finite element analysis model.The results indicate that the proposed connections demonstrate improved resistance to wave forces compared to traditional caissons without such connections.Further studies should include field applications and performance evaluations of various caisson sizes under different environmental and geological conditions.
文摘当前电力营销业务已由单一的供电服务逐渐转变为碳交易、客户侧储能、多能供应、能效服务、分布式电源等综合能源服务,及时响应用户需求变得尤为重要。针对传统建设模式中存在的跨环节协作壁垒、业务需求响应不及时等问题,文章借鉴中台架构设计理念,首先提出一种公共共享服务研运一体化支撑平台(middle-platform service components,MSC),利用模型编排、服务编排、流程编排、界面编排进行微服务灵活实现及扩展;然后,结合架构资产统一管理以及MSC四编排引擎,基于多租户技术进行电力营销业务系统研运一体化建设;最后,通过在客户侧工单中心建设中的应用,证明该模式可为电力营销业务系统建设提供有效支撑。
基金This study was financially supported by the National Natural Science Foundation of China(Grant Nos.51879044 and 51639002)the Shandong Natural Fund(Grant No.ZR2019BEE007)+1 种基金SDUST Research Fund(Grant No.2015TDJH104)the Project oce and Technology Program(Grant No.J18KA184).
文摘A suction caisson can be extracted by applying reverse pumping water,which cannot be regarded as the reverse process of installation because of the dramatically different soil−structure interaction behavior.Model tests were first carried out in this study to investigate the extraction behavior of the modified suction caisson(MSC)and the regular suction caisson(RSC)in sand by reverse pumping water.The effects of the installation ways(suction-assisted or jacking installation)and the reverse pumping rate on the variations of the over-pressure resulting form reverse pumping water were investigated.It was found that neither the RSC nor the MSC can be fully extracted from sand.When the maximum extraction displacement is obtained,the hydraulic gradient of the sand in the suction caisson reaches the critical value,leading to seepage failure.In addition,the maximum extraction displacement decreases with the increasing reverse pumping rate.Under the same reverse pumping rate,the final extraction displacements for the RSC and MSC installed by suction are lower than those for the RSC and MSC installed by jacking.The final extraction displacement of MSC is almost equal to that of the RSC with the same internal compartment length.Based on the force equilibrium,a method of estimating the maximum extraction displacement is proposed.It has been proved that the proposed method can rationally predict the maximum extraction displacement and the corresponding over-pressure.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51639002 and 51379118)the SDUST Research Fund(Grant No.2015KYTD104)
文摘The modified suction caisson(MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson(RSC). The MSC can provide larger lateral bearing capacity and limit the deflection compared with the RSC. Therefore, the MSC can be much more appropriate to use as an offshore wind turbine foundation. Model tests on the MSC in saturated sand subjected to monotonic lateral loading were carried out to investigate the effects of external structure sizes on the sand surface deformation and the earth pressure distribution along the embedded depth. Test results show that the deformation range of the sand surface increases with the increasing width and length of the external structure. The magnitude of sand upheaval around the MSC is smaller than that of the RSC and the sand upheaval value around the MSC in the loading direction decreases with the increasing external structure dimensions. The net earth pressure in the loading direction acting on the internal compartment of the MSC is smaller than that of the RSC at the same embedded depth. The maximum net earth pressure acting on the external structure outer wall in the loading direction is larger than that of the internal compartment, indicating that a considerable amount of the lateral load and moment is resisted by the external skirt structure.
