To achieve durability of the embankment in southern China,a method to control the change of moisture content with the cushion and cover was proposed.A finite element model of cushion and cover considering different ma...To achieve durability of the embankment in southern China,a method to control the change of moisture content with the cushion and cover was proposed.A finite element model of cushion and cover considering different materials and thicknesses for a typical embankment was built,and 20 numerical analyses of transient seepage in the embankment were simulated.The results show that the sand cushion effectively blocks the effect of groundwater capillary rise and the minimum thickness of the sand cushion is 75 cm without considering the atmospheric environment.With the combination of sand cushion and clay cover,as the thickness of the clay cover increases,the duration time of the moisture content from the initial to relative equilibrium state increases,but the equilibrium moisture content is the same as that of the original embankment.Besides,with the combination of the sand cushion and sand cover,the moisture content inside the embankment remains the same,which is consistent with the optimum moisture content during construction.The combination of 75 cm sand cushion and 30 cm sand cover is a very effective method to block groundwater and atmospheric environment,and achieve the control of the humidity stability of the embankment in southern China.展开更多
In order to simulate the airflow in anhydrous case and the water-air flow in groundwater case, a numerical model of airflow in soil was developed. For the nonlinearity of the governing partial differential equation, t...In order to simulate the airflow in anhydrous case and the water-air flow in groundwater case, a numerical model of airflow in soil was developed. For the nonlinearity of the governing partial differential equation, the corresponding discretization and linearization methods were given. Due to the mass transfer between air-phase and water-phase, phase states of the model elements were constantly changing. Thus, parameters of the model were divided into primary ones and secondary ones, and the primary variables changing with phase states and the secondary variables can be obtained by their functional relationship with the primary variables. Additionally, the special definite condition of this numerical model was illustrated. Two examples were given to simulate the airflow in soil whether there was groundwater or not, and the effectiveness of the numerical model is verified by comparing the results of simulation with that of exoeriment.展开更多
基金Project(2017YFC0805307)supported by the National Key Research and Development Program of ChinaProjects(51838001,51878070,51878078,51911530215,51927814)supported by the National Natural Science Foundation of China+5 种基金Project(2018JJ1026)supported by the Excellent Youth Foundation of Natural Science Foundation of Hunan Province,ChinaProject(17A008)supported by the Key Project of Education Department of Hunan Province,ChinaProjects(kfj150103,kfj170106)supported by the Changsha University of Science&Technology via Key Project of Open Research Fund of National Engineering Laboratory of Highway Maintenance Technology,ChinaProject(kfj170404)supported by the Open Fund of Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road and Traffic Safety of Ministry of Education(Changsha University of Science&Technology),ChinaProject(CX2018B527)supported by the Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2018-025)supported by the Training Program for High-level Technical Personnel in Transportation Industry,China。
文摘To achieve durability of the embankment in southern China,a method to control the change of moisture content with the cushion and cover was proposed.A finite element model of cushion and cover considering different materials and thicknesses for a typical embankment was built,and 20 numerical analyses of transient seepage in the embankment were simulated.The results show that the sand cushion effectively blocks the effect of groundwater capillary rise and the minimum thickness of the sand cushion is 75 cm without considering the atmospheric environment.With the combination of sand cushion and clay cover,as the thickness of the clay cover increases,the duration time of the moisture content from the initial to relative equilibrium state increases,but the equilibrium moisture content is the same as that of the original embankment.Besides,with the combination of the sand cushion and sand cover,the moisture content inside the embankment remains the same,which is consistent with the optimum moisture content during construction.The combination of 75 cm sand cushion and 30 cm sand cover is a very effective method to block groundwater and atmospheric environment,and achieve the control of the humidity stability of the embankment in southern China.
基金Project(Y5080022) supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(RC1202) supported by Scientific and Technological Program of Water Resources Department of Zhejiang Province in 2012,ChinaProject(Y201224384) supported by Scientific Research Program of Education Department of Zhejiang Province in 2012,China
文摘In order to simulate the airflow in anhydrous case and the water-air flow in groundwater case, a numerical model of airflow in soil was developed. For the nonlinearity of the governing partial differential equation, the corresponding discretization and linearization methods were given. Due to the mass transfer between air-phase and water-phase, phase states of the model elements were constantly changing. Thus, parameters of the model were divided into primary ones and secondary ones, and the primary variables changing with phase states and the secondary variables can be obtained by their functional relationship with the primary variables. Additionally, the special definite condition of this numerical model was illustrated. Two examples were given to simulate the airflow in soil whether there was groundwater or not, and the effectiveness of the numerical model is verified by comparing the results of simulation with that of exoeriment.
