The equations governing wind-induced internal pressure responses for a two-compartment building with a dominant opening and background porosity were derived.The unsteady form of the Bernoulli equation,the law of mass ...The equations governing wind-induced internal pressure responses for a two-compartment building with a dominant opening and background porosity were derived.The unsteady form of the Bernoulli equation,the law of mass conservation,and adiabatic equation were used for the derivation.The precision of the governing equations was verified by a wind tunnel test on a rigid model of a low-rise building.The results show that the governing equations can effectively analyze the wind-induced internal pressure responses.The internal pressure responses in both compartments are suppressed due to the additional damping provided by background porosity.The responses of internal pressure in both compartments,especially in the compartment without an external opening,decrease with increased lumped leakage area.展开更多
Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,n...Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,numerical simulation of the two tests was performed by three-dimensional finite element method(FEM)using ABAQUS program.The consolidated-drained triaxial test was also simulated by FEM and compared with theoretical results of MCC model.Especially,the behaviors of MCC model during unloading and reloading were analyzed in detail by FEM.The analysis and comparison indicate that the MCC model is able to accurately describe many features of the mechanical behavior of the soil in isotropic consolidation test and consolidated-drained triaxial test.And the MCC model can well describe the variation of excess pore water pressure with the development of axial strain in consolidated-undrained triaxial test,but its ability to predict the relationship between axial strain and shear stress is relatively poor.The comparison also shows that FEM solutions of the MCC model are basically identical to the theoretical ones.In addition,Mandel-Cryer effect unable to be discovered by the conventional triaxial test in laboratories was disclosed by FEM.The analysis of unloading-reloading by FEM demonstrates that the MCC model disobeys the law of energy conservation under the cyclic loading condition if the elastic shear modulus is linearly pressure-dependent.展开更多
The understanding and prediction of preferential fluid flow in porous media have attracted considerable attention in various engineering fields because of the implications of such flows in leading to a non-equilibrium...The understanding and prediction of preferential fluid flow in porous media have attracted considerable attention in various engineering fields because of the implications of such flows in leading to a non-equilibrium fluid flow in the subsurface. In this study, a novel algorithm is proposed to predict preferential flow paths based on the topologically equivalent network of a porous structure and the flow resistance of flow paths. The equivalent flow network was constructed using Poiseuille's law and the maximal inscribed sphere algorithm. The flow resistance of each path was then determined based on Darcy's law. It was determined that fluid tends to follow paths with lower flow resistance. A computer program was developed and applied to an actual porous structure. To validate the algorithm and program, we tested and recorded two-dimensional(2 D) water flow using an ablated Perspex sheet featuring the same porous structure investigated using the analytical calculations. The results show that the measured preferential flow paths are consistent with the predictions.展开更多
基金Project(90715040) supported by the Major Research Program of the National Natural Science Foundation of ChinaProject(50878159) supported by the General Program of the National Natural Science Foundation of China
文摘The equations governing wind-induced internal pressure responses for a two-compartment building with a dominant opening and background porosity were derived.The unsteady form of the Bernoulli equation,the law of mass conservation,and adiabatic equation were used for the derivation.The precision of the governing equations was verified by a wind tunnel test on a rigid model of a low-rise building.The results show that the governing equations can effectively analyze the wind-induced internal pressure responses.The internal pressure responses in both compartments are suppressed due to the additional damping provided by background porosity.The responses of internal pressure in both compartments,especially in the compartment without an external opening,decrease with increased lumped leakage area.
基金Project(2011J01308) supported by the Natural Science Foundation of Fujian Province,China
文摘Isotropic consolidation test and consolidated-undrained triaxial test were first undertaken to obtain the parameters of the modified cam-clay(MCC)model and the behavior of natural clayey soil.Then,for the first time,numerical simulation of the two tests was performed by three-dimensional finite element method(FEM)using ABAQUS program.The consolidated-drained triaxial test was also simulated by FEM and compared with theoretical results of MCC model.Especially,the behaviors of MCC model during unloading and reloading were analyzed in detail by FEM.The analysis and comparison indicate that the MCC model is able to accurately describe many features of the mechanical behavior of the soil in isotropic consolidation test and consolidated-drained triaxial test.And the MCC model can well describe the variation of excess pore water pressure with the development of axial strain in consolidated-undrained triaxial test,but its ability to predict the relationship between axial strain and shear stress is relatively poor.The comparison also shows that FEM solutions of the MCC model are basically identical to the theoretical ones.In addition,Mandel-Cryer effect unable to be discovered by the conventional triaxial test in laboratories was disclosed by FEM.The analysis of unloading-reloading by FEM demonstrates that the MCC model disobeys the law of energy conservation under the cyclic loading condition if the elastic shear modulus is linearly pressure-dependent.
基金supported by the National Natural Science Foundation of China(Grants Nos.51374213,51674251&51727807)the State Key Research Development Program of China(Grant No.2016YFC0600705)+2 种基金the National Natural Science Fund for Distinguished Young Scholars(Grant No.51125017)the Fund for Creative Research and Development Group Program of Jiangsu Province(2014-27)the Priority Academic Program Development of Jiangsu Higher Education Institutions(Grant No.PAPD-2014)
文摘The understanding and prediction of preferential fluid flow in porous media have attracted considerable attention in various engineering fields because of the implications of such flows in leading to a non-equilibrium fluid flow in the subsurface. In this study, a novel algorithm is proposed to predict preferential flow paths based on the topologically equivalent network of a porous structure and the flow resistance of flow paths. The equivalent flow network was constructed using Poiseuille's law and the maximal inscribed sphere algorithm. The flow resistance of each path was then determined based on Darcy's law. It was determined that fluid tends to follow paths with lower flow resistance. A computer program was developed and applied to an actual porous structure. To validate the algorithm and program, we tested and recorded two-dimensional(2 D) water flow using an ablated Perspex sheet featuring the same porous structure investigated using the analytical calculations. The results show that the measured preferential flow paths are consistent with the predictions.
