A test rig is built to model the dynamic response of submarine pipelines with an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. Model ...A test rig is built to model the dynamic response of submarine pipelines with an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. Model tests are carried out to consider the effects of exciting wave directions and types. Based on the experimental results, two hydrodynamic force models derived from Morisen equation and Wake model are presented respectively. By use of hydrodynamic force models suitable for free spanning submarine pipelines under earthquakes, diseretized equations of motion are obtained and finite element models are established to analyze dynamic response of free spanning submarine pipeline subjected to multi-support seismic excitations. The comparison of numerical results with experimental results shows that the improved Morison and Wake hydrodynamic force models could satisfactorily predict dynamic response on the free spanning submarine pipelines subjected to earthquakes.展开更多
It is very difficult,for the component-type ship mathematical model,to estimate the interaction force coefficients among the hull,propeller and rudder. Some coefficients such as wake fraction and flow straightening co...It is very difficult,for the component-type ship mathematical model,to estimate the interaction force coefficients among the hull,propeller and rudder. Some coefficients such as wake fraction and flow straightening coefficient were studied from the model tests in diffierent loading conditions and the normal force of rudder was tested in captive model tests to obtain the coefficients. From these results of the tests,the flow straightening coefficients increase with the increase of trims or drafts. Similarly,wake fraction coefficients are larger for the large drafts,however,become small as the trims increase. The resistance is obviously different in fully loaded condition with the trims by stern,however ,the difference is not evident when the draft decreases and the bulbous bow is above the water surface.展开更多
To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbr...To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbration theory and two reasonable assumptions.And the new law is vertified with an ice-induced pier virbration example.The numerical calculation results show that,firstly,the error of frequency factor between test value and theory value is small as well as that of displacement and velocity;Secondly,the time scale completely meet the similitude relation,the waveforms anastomotic well,and the phenomenon of offset and omit do not occur;Thirdly,as the damping ratio between prototype and model is nearly equal,the improved similitude law will still be applied.Therefore,the new modified similitude law is feasible to study dynamic ice force model test and can provide reference for the ice mechanics.展开更多
The state of deep mine rigid shaft fUrniture horizontal force calculation in China is introduced and the calculating model of horizontal force is determined. Based on the interaction between hoisting vessel and shaft ...The state of deep mine rigid shaft fUrniture horizontal force calculation in China is introduced and the calculating model of horizontal force is determined. Based on the interaction between hoisting vessel and shaft furniture, the vertical mobel test device is built and a large number of model tests and analyses are carried out. At last, the relationship between horizontal force and hoisting end load, hoisting speed or bunton level interval is gained. The three parameters horizontal force calculating equation of beep mine rigid shaft furniture is given and it can guide the design and calculation of shaft engineering.展开更多
Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial stresses.An approach that considers only loading,is generally used in tunnel model ...Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial stresses.An approach that considers only loading,is generally used in tunnel model testing.However,this approach is incapable of characterizing the unloading effects induced by excavation on surrounding rocks and hence presents radial and tangential stress paths during the failure process that are different from the actual stress state of tunnels.This paper carried out a comparative analysis using laboratory model testing and particle flow code(PFC2D)-based numerical simulation,and shed light upon the crack propagation process and,microscopic stress and force chain variations during the loading-unloading process.The failure mode observed in the unloading model test is shear failure.The force chains are strongly correlated with the concrete fracture propagation.In addition,the change patterns of the radial and tangential stresses of surrounding rocks in the broken region,as well as the influence of the initial stress on failure loads are revealed.The surrounding soil of tunnel failure evolution as well as extent and shape of the damage zone during the excavation-induced unloading were also studied.展开更多
Linear flux-switching permanent magnet motors(LFSPMs) have been proposed for long stator applications such as rail transit. However, the conventional linear permanent magnet synchronous motor(LPMSM) suffers from thrus...Linear flux-switching permanent magnet motors(LFSPMs) have been proposed for long stator applications such as rail transit. However, the conventional linear permanent magnet synchronous motor(LPMSM) suffers from thrust ripple, which degrades the motor performance. The thrust ripple in LFSPMs is mainly caused by detent force and asymmetric electromagnetic parameters, excluding external disturbances. Moreover, the 12/13 slot-pole LFSPM exhibits unique inductance characteristics, which lead to different effects on thrust ripple. First, the detent force in the LFSPM is analyzed through finite element method(FEM). In addition, new finite element(FE) models are proposed for further analysis of the cogging force in LFSPMs. Second, the unique inductance characteristics of the 12/13 slot-pole LFSPM are investigated, and then the thrust ripple caused by asymmetric electromagnetic parameters is calculated by the virtual displacement method. Third, the mathematical model considering the thrust ripple is established for the LFSPM, which provides a foundation for subsequent research on thrust ripple suppression control strategies. Finally, the thrust ripple analysis is validated by comparing FEM results, modeling simulations, and experimental data.展开更多
Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent fe...Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.展开更多
Wind-tunnel tests of a large-scale sectional model with synchronous measurements of force and vibration responses were carried out to investigate the nonlinear behaviors of vertical vortex-induced forces （VIFs） on t...Wind-tunnel tests of a large-scale sectional model with synchronous measurements of force and vibration responses were carried out to investigate the nonlinear behaviors of vertical vortex-induced forces （VIFs） on three typical box decks （i.e., fully closed box, centrally slotted box, and semi-closed box）. The mechanisms of the onset, development, and self-limiting phenomenon of the vertical vortex-induced vibration （VlV） were also explored by analyzing the energy evolution of different vertical VIF components and their contributions to the vertical VIV responses. The results show that the nonlinear components of the vertical VIF often differ from deck to deck; the most important components of the vertical VIF, governing the stable amplitudes of the vertical VIV responses, are the linear and cubic components of velocity contained in the self-excited aerodynamic damping forces. The former provides a constant negative damping ratio to the vibration system and is thus the essential power driving the development of the VIV amplitude, while the latter provides a positive damping ratio proportional to the square of the vibration velocity and is actually the inherent factor making the VIV amplitude self-limiting. On these bases, a universal simplified nonlinear mathematical model of the vertical VIF on box decks of bridges is presented and verified in this paper; it can be used to predict the stable amplitudes of the vertical VIV of long-span bridges with satisfactory accuracy.展开更多
Accurately forecasting the operational performance of a tunnel boring machine(TBM)in advance is useful for making timely adjustments to boring parameters,thereby enhancing overall boring efficiency.In this study,we us...Accurately forecasting the operational performance of a tunnel boring machine(TBM)in advance is useful for making timely adjustments to boring parameters,thereby enhancing overall boring efficiency.In this study,we used the Informer model to predict a critical performance parameter of the TBM,namely thrust.Leveraging data from the Guangzhou Metro Line 22 project on the big data platform in China,the model’s performance was validated,while data from Line 18 were used to assess its generalization capability.Results revealed that the Informer model surpasses random forest(RF),extreme gradient boosting(XGB),support vector regression(SVR),k-nearest neighbors(KNN),back propagation(BP),and long short-term memory(LSTM)models in both prediction accuracy and generalization performance.In addition,the optimal input lengths for maximizing accuracy in the single-time-step output model are within the range of 8–24,while for the multiple-time-step output model,the optimal input length is 8.Furthermore,the last predicted value in the case of multiple-time-step outputs showed the highest accuracy.It was also found that relaxation of the Pearson analysis method metrics to 0.95 improved the performance of the model.Finally,the prediction results were most affected by earth pressure,rotation speed,torque,boring speed,and the surrounding rock grade.The model can provide useful guidance for constructors when adjusting TBM operation parameters.展开更多
For the study on the ice-induced vibration of a compliant mono-cone structure,a series of model tests were performed from 2004 to 2006.In these tests,the ice sheet before the compliant conical structure was found to b...For the study on the ice-induced vibration of a compliant mono-cone structure,a series of model tests were performed from 2004 to 2006.In these tests,the ice sheet before the compliant conical structure was found to be failed in two-time breaking.Based on this important finding,model tests study of the ice force on a compliant multi-cone structure were performed from 2006 to 2007.In these tests,the ice sheet broke before each single cone non-simultaneously.The exciting energy of the total ice force was found to be in a wide range of frequencies,and the structure can be easily excited with nonlinear resonance.展开更多
Depression is a chronic,recurring and potentially life-threatening illness that affects up to 20%of the population across the world.Despite its prevalence and considerable impact on human,little is known about its pat...Depression is a chronic,recurring and potentially life-threatening illness that affects up to 20%of the population across the world.Despite its prevalence and considerable impact on human,little is known about its pathogenesis.One of the major reasons is the restricted availability of validated animal models due to the absence of consensus on the pathology and etiology of depression.Besides,some core symptoms such as depressed mood,feeling of worthlessness,and recurring thoughts of death or suicide,are impossible to be modeled on laboratory animals.Currently,the criteria for identifying animal models of depression rely on either of the 2 principles：actions of known antidepressants and responses to stress.This review mainly focuses on the most widely used animal models of depression,including learned helplessness,chronic mild stress,and social defeat paradigms.Also,the behavioral tests for screening antidepressants,such as forced swimming test and tail suspension test,are also discussed.The advantages and major drawbacks of each model are evaluated.In prospective,new techniques that will be beneficial for developing novel animal models or detecting depression are discussed.展开更多
The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to m...The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.展开更多
The changes of three components of aerodynamic force were discussed with the attack angle conversion for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was c...The changes of three components of aerodynamic force were discussed with the attack angle conversion for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was conducted to obtain its three components of aerodynamic force including 75 conditions of the construction stage, the bridge without vehicles and the bridge with vehicles from - 12 degrees to ＋ 12 degrees. For the bridge with vehicles, the drag force coefficient and the absolute value of both lift coefficient and moment coefficient were decreased by the vehicles. The test resuh shows that the bridge railing and vehicles have much influence on the three components of aerodynamic force of the vehicle-bridge system for Shanghai Yangtze River Bridge.展开更多
Based on the 1st order cnoidal wave theory, the wave diffraction around the pier group inshallow water is studied in this paper. The formulas for calculating the nonlinear wave forces are also presented here. In order...Based on the 1st order cnoidal wave theory, the wave diffraction around the pier group inshallow water is studied in this paper. The formulas for calculating the nonlinear wave forces are also presented here. In order to verify the theoretical results, model tests are conducted in the wave flume in The State Key Laboratory of Coastal and Offshore Engineering located in Dalian University of Technology. The range of the wave parameters in the experiments is characteristic wave period T g/d^(1/2) = 8.08- 22.86, characteristic wave height H/ d= 0.1 ~ 0.45. The results obtained from the experiments agree with the theoretical results quite well. It is shown that, in shallow water the nonlinear wave forces acting on a pier group are greater than those calculated by linear wave theory, the value of increment in wave force increases with the increases of the nonlinearity of the wave. In the wave range studied in this paper, the nonlinear wave force can reach over 4 times the force calculatecd by linear wave theory. Thus, it is suggested that, when Tg / d^(1/2)> 8, the wave force on the piers in the pier group in shallow water should be calculated by using the cnoidal wave theory.展开更多
Determination of the grouting anchor pullout force is a key step during the design of anchor-pull retaining wall, but it is mostly determined relied on empirical formula at present, and the rationality and the safety ...Determination of the grouting anchor pullout force is a key step during the design of anchor-pull retaining wall, but it is mostly determined relied on empirical formula at present, and the rationality and the safety cannot be effectively guaranteed. Based on the engineering case of the gravity retaining wall of Qinglin Freeway, the model test was designed, and combined with the results of the ABAQUS finite element numerical analysis, it was analyzed that how the anchor axial pulling force distributes. The results showed that the force of the anchor near the wall bolt was large and which far from the wall was small and the ultimate pullout force was proportional to the length, diameter and shear strength. When the end tension of the anchor was small, the top load played a leading role on the anchor tension. This conclusion confirmed the calculation formula of ultimate pullout force was and provided a theoretical basis for anchor-pull retaining wall design and calculation.展开更多
基金supported jointly by the National Natural Science Foundation of China and Korea Scienceand Engineering Foundation(Grant No.50811140341)
文摘A test rig is built to model the dynamic response of submarine pipelines with an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. Model tests are carried out to consider the effects of exciting wave directions and types. Based on the experimental results, two hydrodynamic force models derived from Morisen equation and Wake model are presented respectively. By use of hydrodynamic force models suitable for free spanning submarine pipelines under earthquakes, diseretized equations of motion are obtained and finite element models are established to analyze dynamic response of free spanning submarine pipeline subjected to multi-support seismic excitations. The comparison of numerical results with experimental results shows that the improved Morison and Wake hydrodynamic force models could satisfactorily predict dynamic response on the free spanning submarine pipelines subjected to earthquakes.
基金the Foundation Item "Knowledge-based Ship-design Hyper-integrated Platform(KSHIP)" of Ministry of Education of China
文摘It is very difficult,for the component-type ship mathematical model,to estimate the interaction force coefficients among the hull,propeller and rudder. Some coefficients such as wake fraction and flow straightening coefficient were studied from the model tests in diffierent loading conditions and the normal force of rudder was tested in captive model tests to obtain the coefficients. From these results of the tests,the flow straightening coefficients increase with the increase of trims or drafts. Similarly,wake fraction coefficients are larger for the large drafts,however,become small as the trims increase. The resistance is obviously different in fully loaded condition with the trims by stern,however ,the difference is not evident when the draft decreases and the bulbous bow is above the water surface.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50678033)
文摘To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbration theory and two reasonable assumptions.And the new law is vertified with an ice-induced pier virbration example.The numerical calculation results show that,firstly,the error of frequency factor between test value and theory value is small as well as that of displacement and velocity;Secondly,the time scale completely meet the similitude relation,the waveforms anastomotic well,and the phenomenon of offset and omit do not occur;Thirdly,as the damping ratio between prototype and model is nearly equal,the improved similitude law will still be applied.Therefore,the new modified similitude law is feasible to study dynamic ice force model test and can provide reference for the ice mechanics.
文摘The state of deep mine rigid shaft fUrniture horizontal force calculation in China is introduced and the calculating model of horizontal force is determined. Based on the interaction between hoisting vessel and shaft furniture, the vertical mobel test device is built and a large number of model tests and analyses are carried out. At last, the relationship between horizontal force and hoisting end load, hoisting speed or bunton level interval is gained. The three parameters horizontal force calculating equation of beep mine rigid shaft furniture is given and it can guide the design and calculation of shaft engineering.
基金the support by the National Natural Science Foundation of China(No.51608071)Natural Science Foundation of Chongqing,China(cstc2018jcyjAX0632)+1 种基金General Financial Grant from the China Postdoctoral Science Foundation(Grant No.2017M620414)the Special Funding for Post-doctoral Researchers in Chongqing(No.Xm2017007).
文摘Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial stresses.An approach that considers only loading,is generally used in tunnel model testing.However,this approach is incapable of characterizing the unloading effects induced by excavation on surrounding rocks and hence presents radial and tangential stress paths during the failure process that are different from the actual stress state of tunnels.This paper carried out a comparative analysis using laboratory model testing and particle flow code(PFC2D)-based numerical simulation,and shed light upon the crack propagation process and,microscopic stress and force chain variations during the loading-unloading process.The failure mode observed in the unloading model test is shear failure.The force chains are strongly correlated with the concrete fracture propagation.In addition,the change patterns of the radial and tangential stresses of surrounding rocks in the broken region,as well as the influence of the initial stress on failure loads are revealed.The surrounding soil of tunnel failure evolution as well as extent and shape of the damage zone during the excavation-induced unloading were also studied.
基金partly supported by the CAS Project for Young Scientists in Basic Research under Grant YSBR-045the National Natural Science Foundation of China under Grant 52307071。
文摘Linear flux-switching permanent magnet motors(LFSPMs) have been proposed for long stator applications such as rail transit. However, the conventional linear permanent magnet synchronous motor(LPMSM) suffers from thrust ripple, which degrades the motor performance. The thrust ripple in LFSPMs is mainly caused by detent force and asymmetric electromagnetic parameters, excluding external disturbances. Moreover, the 12/13 slot-pole LFSPM exhibits unique inductance characteristics, which lead to different effects on thrust ripple. First, the detent force in the LFSPM is analyzed through finite element method(FEM). In addition, new finite element(FE) models are proposed for further analysis of the cogging force in LFSPMs. Second, the unique inductance characteristics of the 12/13 slot-pole LFSPM are investigated, and then the thrust ripple caused by asymmetric electromagnetic parameters is calculated by the virtual displacement method. Third, the mathematical model considering the thrust ripple is established for the LFSPM, which provides a foundation for subsequent research on thrust ripple suppression control strategies. Finally, the thrust ripple analysis is validated by comparing FEM results, modeling simulations, and experimental data.
文摘Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.
基金The work described in this paper was jointly supported by the National Natural Science Foundation of China （51478360, 51323013, and 50978204）.
文摘Wind-tunnel tests of a large-scale sectional model with synchronous measurements of force and vibration responses were carried out to investigate the nonlinear behaviors of vertical vortex-induced forces （VIFs） on three typical box decks （i.e., fully closed box, centrally slotted box, and semi-closed box）. The mechanisms of the onset, development, and self-limiting phenomenon of the vertical vortex-induced vibration （VlV） were also explored by analyzing the energy evolution of different vertical VIF components and their contributions to the vertical VIV responses. The results show that the nonlinear components of the vertical VIF often differ from deck to deck; the most important components of the vertical VIF, governing the stable amplitudes of the vertical VIV responses, are the linear and cubic components of velocity contained in the self-excited aerodynamic damping forces. The former provides a constant negative damping ratio to the vibration system and is thus the essential power driving the development of the VIV amplitude, while the latter provides a positive damping ratio proportional to the square of the vibration velocity and is actually the inherent factor making the VIV amplitude self-limiting. On these bases, a universal simplified nonlinear mathematical model of the vertical VIF on box decks of bridges is presented and verified in this paper; it can be used to predict the stable amplitudes of the vertical VIV of long-span bridges with satisfactory accuracy.
基金supported by the National Natural Science Foundation of China(No.41827807)the Foundation of the Guangdong Provincial Key Laboratory of Modern Civil Engineering Technology(No.2021B1212040003),China.
文摘Accurately forecasting the operational performance of a tunnel boring machine(TBM)in advance is useful for making timely adjustments to boring parameters,thereby enhancing overall boring efficiency.In this study,we used the Informer model to predict a critical performance parameter of the TBM,namely thrust.Leveraging data from the Guangzhou Metro Line 22 project on the big data platform in China,the model’s performance was validated,while data from Line 18 were used to assess its generalization capability.Results revealed that the Informer model surpasses random forest(RF),extreme gradient boosting(XGB),support vector regression(SVR),k-nearest neighbors(KNN),back propagation(BP),and long short-term memory(LSTM)models in both prediction accuracy and generalization performance.In addition,the optimal input lengths for maximizing accuracy in the single-time-step output model are within the range of 8–24,while for the multiple-time-step output model,the optimal input length is 8.Furthermore,the last predicted value in the case of multiple-time-step outputs showed the highest accuracy.It was also found that relaxation of the Pearson analysis method metrics to 0.95 improved the performance of the model.Finally,the prediction results were most affected by earth pressure,rotation speed,torque,boring speed,and the surrounding rock grade.The model can provide useful guidance for constructors when adjusting TBM operation parameters.
基金supported bythe National High Technology Research and Development Program of China(863Program,Grant No.2003AA602150-3)the National Natural Science Foundation of China(Grant No.50609015)
文摘For the study on the ice-induced vibration of a compliant mono-cone structure,a series of model tests were performed from 2004 to 2006.In these tests,the ice sheet before the compliant conical structure was found to be failed in two-time breaking.Based on this important finding,model tests study of the ice force on a compliant multi-cone structure were performed from 2006 to 2007.In these tests,the ice sheet broke before each single cone non-simultaneously.The exciting energy of the total ice force was found to be in a wide range of frequencies,and the structure can be easily excited with nonlinear resonance.
文摘Depression is a chronic,recurring and potentially life-threatening illness that affects up to 20%of the population across the world.Despite its prevalence and considerable impact on human,little is known about its pathogenesis.One of the major reasons is the restricted availability of validated animal models due to the absence of consensus on the pathology and etiology of depression.Besides,some core symptoms such as depressed mood,feeling of worthlessness,and recurring thoughts of death or suicide,are impossible to be modeled on laboratory animals.Currently,the criteria for identifying animal models of depression rely on either of the 2 principles：actions of known antidepressants and responses to stress.This review mainly focuses on the most widely used animal models of depression,including learned helplessness,chronic mild stress,and social defeat paradigms.Also,the behavioral tests for screening antidepressants,such as forced swimming test and tail suspension test,are also discussed.The advantages and major drawbacks of each model are evaluated.In prospective,new techniques that will be beneficial for developing novel animal models or detecting depression are discussed.
文摘The shielding effect of the front pile-row on the ice force acting on the back pile-row is studied by ice force model tests. In the tests, the front pile-row is designed to model jacket legs and the back pile-row to model the water resisting pipe-phalanx within the jacket. The shielding factor for ice force corresponding to different conditions are given in this paper. The research indicates that there are many factors, including the longitudinal and lateral spacing between the front and back pile-row, ice attacking angle and the ratio of pile diameter to ice thickness, that influence the shielding effect on ice force.
基金Sponsored by the Key Project of the National Natural Science Foundation of China (Grant No.90715039)
文摘The changes of three components of aerodynamic force were discussed with the attack angle conversion for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was conducted to obtain its three components of aerodynamic force including 75 conditions of the construction stage, the bridge without vehicles and the bridge with vehicles from - 12 degrees to ＋ 12 degrees. For the bridge with vehicles, the drag force coefficient and the absolute value of both lift coefficient and moment coefficient were decreased by the vehicles. The test resuh shows that the bridge railing and vehicles have much influence on the three components of aerodynamic force of the vehicle-bridge system for Shanghai Yangtze River Bridge.
文摘Based on the 1st order cnoidal wave theory, the wave diffraction around the pier group inshallow water is studied in this paper. The formulas for calculating the nonlinear wave forces are also presented here. In order to verify the theoretical results, model tests are conducted in the wave flume in The State Key Laboratory of Coastal and Offshore Engineering located in Dalian University of Technology. The range of the wave parameters in the experiments is characteristic wave period T g/d^(1/2) = 8.08- 22.86, characteristic wave height H/ d= 0.1 ~ 0.45. The results obtained from the experiments agree with the theoretical results quite well. It is shown that, in shallow water the nonlinear wave forces acting on a pier group are greater than those calculated by linear wave theory, the value of increment in wave force increases with the increases of the nonlinearity of the wave. In the wave range studied in this paper, the nonlinear wave force can reach over 4 times the force calculatecd by linear wave theory. Thus, it is suggested that, when Tg / d^(1/2)> 8, the wave force on the piers in the pier group in shallow water should be calculated by using the cnoidal wave theory.
文摘Determination of the grouting anchor pullout force is a key step during the design of anchor-pull retaining wall, but it is mostly determined relied on empirical formula at present, and the rationality and the safety cannot be effectively guaranteed. Based on the engineering case of the gravity retaining wall of Qinglin Freeway, the model test was designed, and combined with the results of the ABAQUS finite element numerical analysis, it was analyzed that how the anchor axial pulling force distributes. The results showed that the force of the anchor near the wall bolt was large and which far from the wall was small and the ultimate pullout force was proportional to the length, diameter and shear strength. When the end tension of the anchor was small, the top load played a leading role on the anchor tension. This conclusion confirmed the calculation formula of ultimate pullout force was and provided a theoretical basis for anchor-pull retaining wall design and calculation.
