Several methods for evaluating the sublayer suspension beneath old pavement with falling weight deflectormeter(FWD), were summarized and the respective advantages and disadvantages were analyzed. Based on these method...Several methods for evaluating the sublayer suspension beneath old pavement with falling weight deflectormeter(FWD), were summarized and the respective advantages and disadvantages were analyzed. Based on these methods, the evaluation principles were improved and a new type of the neural network, functional-link neural network was proposed to evaluate the sublayer suspension with FWD test results. The concept of function link, learning method of functional-link neural network and the establishment process of neural network model were studied in detail. Based on the old pavement over-repairing engineering of Kaiping section, Guangdong Province in G325 National Highway, the application of functional-link neural network in evaluation of sublayer suspension beneath old pavement based on FWD test data on the spot was investigated. When learning rate is 0.1 and training cycles are 405, the functional-link network error is less than 0.000 1, while the optimum chosen 4-8-1 BP needs over 10 000 training cycles to reach the same accuracy with less precise evaluation results. Therefore, in contrast to common BP neural network,the functional-link neural network adopts single layer structure to learn and calculate, which simplifies the network, accelerates the convergence speed and improves the accuracy. Moreover the trained functional-link neural network can be (adopted) to directly evaluate the sublayer suspension based on FWD test data on the site. Engineering practice indicates that the functional-link neural model gains very excellent results and effectively guides the pavement over-repairing construction.展开更多
A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo...A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo loading system.In all the tests,the amplitude of loading was±160 kPa;the frequency of loading was 2 Hz.To better ascertain the effect of reinforcement,an unreinforced square footing was first tested.This was followed by a series of tests,each with a single layer of reinforcement.The reinforcement was placed at depths of 0.3B,0.6B and 0.9B,where B is the width of footing.The optimal depth of reinforcement was found to be 0.6B.The effect of adopting this value versus the other two depths was quantified.The single layer of geogrid had an effective reinforcement depth of 1.7B below the footing base.The increase of the depth between the topmost geogrid layer and the bottom of the footing(within the range of 0.9B)did not change the failure mode of the foundation.展开更多
In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic ana...In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.展开更多
In the structural design of the high pier,in order to analyze the strength and structure stability,the pier was often considered a thin-walled structure.Elastoplastic incremental theory was used to establish the model...In the structural design of the high pier,in order to analyze the strength and structure stability,the pier was often considered a thin-walled structure.Elastoplastic incremental theory was used to establish the model of elastoplastic stability of high pier.By considering the combined action of pile,soil and pier together,the destabilization bearing capacity was calculated by using 3-D finite element method(3-D FEM) for piers with different pile and section height.Meanwhile,the equivalent stress in different sections of pier was computed and the processor of destabilization was discussed.When the pier is lower,the bearing capacity under mutual effect of pile,soil and pier is less than the situation when mutual effect is not considered;when the pier is higher,their differences are not conspicuous.Along with the increase of the cross-sectional height,the direction of destabilization bearing capacity is varied and the ultimate capacity is buildup.The results of a stability analysis example are almost identical with the practice.展开更多
To determine structure and parameters of a rheological constitutive model for rocks,a new method based on differential evolution(DE) algorithm combined with FLAC3D(a numerical code for geotechnical engineering) was pr...To determine structure and parameters of a rheological constitutive model for rocks,a new method based on differential evolution(DE) algorithm combined with FLAC3D(a numerical code for geotechnical engineering) was proposed for identification of the global optimum coupled of model structure and its parameters.At first,stochastic coupled mode was initialized,the difference in displacement between the numerical value and in-situ measurements was regarded as fitness value to evaluate quality of the coupled mode.Then the coupled-mode was updated continually using DE rule until the optimal parameters were found.Thus,coupled-mode was identified adaptively during back analysis process.The results of applications to Jinping tunnels in China show that the method is feasible and efficient for identifying the coupled-mode of constitutive structure and its parameters.The method overcomes the limitation of the traditional method and improves significantly precision and speed of displacement back analysis process.展开更多
文摘Several methods for evaluating the sublayer suspension beneath old pavement with falling weight deflectormeter(FWD), were summarized and the respective advantages and disadvantages were analyzed. Based on these methods, the evaluation principles were improved and a new type of the neural network, functional-link neural network was proposed to evaluate the sublayer suspension with FWD test results. The concept of function link, learning method of functional-link neural network and the establishment process of neural network model were studied in detail. Based on the old pavement over-repairing engineering of Kaiping section, Guangdong Province in G325 National Highway, the application of functional-link neural network in evaluation of sublayer suspension beneath old pavement based on FWD test data on the spot was investigated. When learning rate is 0.1 and training cycles are 405, the functional-link network error is less than 0.000 1, while the optimum chosen 4-8-1 BP needs over 10 000 training cycles to reach the same accuracy with less precise evaluation results. Therefore, in contrast to common BP neural network,the functional-link neural network adopts single layer structure to learn and calculate, which simplifies the network, accelerates the convergence speed and improves the accuracy. Moreover the trained functional-link neural network can be (adopted) to directly evaluate the sublayer suspension based on FWD test data on the site. Engineering practice indicates that the functional-link neural model gains very excellent results and effectively guides the pavement over-repairing construction.
基金Projects(41962017,51469005)supported by the National Natural Science Foundation of ChinaProject(2017GXNSFAA198170)supported by the Natural Science Foundation in Guangxi Province,China+1 种基金Project supported by the Guangxi University of Science and Technology Innovation Team Support Plan,ChinaProject supported by the High Level Innovation Team and Outstanding Scholars Program of Guangxi Institutions of Higher Learning,China。
文摘A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo loading system.In all the tests,the amplitude of loading was±160 kPa;the frequency of loading was 2 Hz.To better ascertain the effect of reinforcement,an unreinforced square footing was first tested.This was followed by a series of tests,each with a single layer of reinforcement.The reinforcement was placed at depths of 0.3B,0.6B and 0.9B,where B is the width of footing.The optimal depth of reinforcement was found to be 0.6B.The effect of adopting this value versus the other two depths was quantified.The single layer of geogrid had an effective reinforcement depth of 1.7B below the footing base.The increase of the depth between the topmost geogrid layer and the bottom of the footing(within the range of 0.9B)did not change the failure mode of the foundation.
文摘In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.
基金Project(06JJ5080) supported by the Hunan Natural Science Foundation of ChinaProject(05026B) supported by the Young Science Foundation of Central South University of Forestry and Technology
文摘In the structural design of the high pier,in order to analyze the strength and structure stability,the pier was often considered a thin-walled structure.Elastoplastic incremental theory was used to establish the model of elastoplastic stability of high pier.By considering the combined action of pile,soil and pier together,the destabilization bearing capacity was calculated by using 3-D finite element method(3-D FEM) for piers with different pile and section height.Meanwhile,the equivalent stress in different sections of pier was computed and the processor of destabilization was discussed.When the pier is lower,the bearing capacity under mutual effect of pile,soil and pier is less than the situation when mutual effect is not considered;when the pier is higher,their differences are not conspicuous.Along with the increase of the cross-sectional height,the direction of destabilization bearing capacity is varied and the ultimate capacity is buildup.The results of a stability analysis example are almost identical with the practice.
基金Project (50809017) supported by the National Natural Science Foundation of China
文摘To determine structure and parameters of a rheological constitutive model for rocks,a new method based on differential evolution(DE) algorithm combined with FLAC3D(a numerical code for geotechnical engineering) was proposed for identification of the global optimum coupled of model structure and its parameters.At first,stochastic coupled mode was initialized,the difference in displacement between the numerical value and in-situ measurements was regarded as fitness value to evaluate quality of the coupled mode.Then the coupled-mode was updated continually using DE rule until the optimal parameters were found.Thus,coupled-mode was identified adaptively during back analysis process.The results of applications to Jinping tunnels in China show that the method is feasible and efficient for identifying the coupled-mode of constitutive structure and its parameters.The method overcomes the limitation of the traditional method and improves significantly precision and speed of displacement back analysis process.
