With consideration of the special hydrogeological conditions and layout characteristics of the hydraulic structures, the seepage control measures of dam abutment and underground powerhouse on the right bank of JinPing...With consideration of the special hydrogeological conditions and layout characteristics of the hydraulic structures, the seepage control measures of dam abutment and underground powerhouse on the right bank of JinPing-I hydropower station is drawn up. Based on the three dimensional finite element analysis of seepage control with dry area virtual flow constant mesh analysis method, the rationality of the seepage control measures of dam abutment and underground powerhouse has been verified and the key factors affecting the effect of seepage have been compared. In combination with the curtain of dam abutment, the curtain of underground powerhouse is reasonable. The results showed that the steel liner of penstock after the curtain is necessary.展开更多
An interface crack with a frictionless contact zone at the right crack-tip between two dissimilar magnetoelectroelastic materials under the action of concentrated magnetoelectromechanical loads on the crack faces is c...An interface crack with a frictionless contact zone at the right crack-tip between two dissimilar magnetoelectroelastic materials under the action of concentrated magnetoelectromechanical loads on the crack faces is considered. The open part of the crack is assumed to be magnetically impermeable and electrically permeable. The Dirichlet-Riemann boundary value problem is formulated and solved analytically. Stress, magnetic induction and electrical displacement intensity factors as well as energy release rate are thus found in analytical forms. Analytical expressions for the contact zone length have been derived. Some numerical results are presented and compared with those based on the other crack surface conditions. It is shown clearly that the location and magnitude of the applied loads could significantly affect the contact zone length, the stress intensity factor and the energy release rate.展开更多
This study proposes a new approach in which an impermeable plate is placed under the pipeline to prevent the local scour around the pipeline.In order to understand the performance of this approach,the finite volume me...This study proposes a new approach in which an impermeable plate is placed under the pipeline to prevent the local scour around the pipeline.In order to understand the performance of this approach,the finite volume method(FVM) and volume of fluid(VOF) method are adopted to simulate the flow field around the pipeline.The pressure distribution along the sandy bed surface is obtained by considering the variation of water surface.Furthermore,the effects of water depth,unidirectional and bidirectional impermeable plates on pressure difference are discussed.The seepage flow field of sandy bed near underwater pipeline is numerically simulated using the laminar and porous media model.On this basis,the effect of the impermeable plate length on hydraulic gradient is investigated and the critical length of impermeable plate is obtained.The simulated results show that when the water depth is smaller than 5.00D(D is the diameter of pipeline),the effect of the water depth on the pressure difference is remarkable.The pressure differences between two endpoints of both the unidirectional and bidirectional plates decrease with the increase of the plate length.The variations of the pressure differences for both the unidirectional and bidirectional plates are similar.With the increase of plate length,the hydraulic gradient decreases and the piping at the seepage exit is avoided effectively as long as it reaches a certain length.Such a critical length of the plate decreases with the increase of the water depth.When water depth is larger than 4.00D,the effect of the water depth on the critical length is small.For the same water depth,the critical length of impermeable plate increases with the increase of the dimensionless flow parameter.Numerical simulation results are in good agreement with the available experimental measurements.展开更多
文摘With consideration of the special hydrogeological conditions and layout characteristics of the hydraulic structures, the seepage control measures of dam abutment and underground powerhouse on the right bank of JinPing-I hydropower station is drawn up. Based on the three dimensional finite element analysis of seepage control with dry area virtual flow constant mesh analysis method, the rationality of the seepage control measures of dam abutment and underground powerhouse has been verified and the key factors affecting the effect of seepage have been compared. In combination with the curtain of dam abutment, the curtain of underground powerhouse is reasonable. The results showed that the steel liner of penstock after the curtain is necessary.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10772123, 11072160)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0971)the Natural Science Fund for Outstanding People of Hebei Province(Grant No. A2009001624)
文摘An interface crack with a frictionless contact zone at the right crack-tip between two dissimilar magnetoelectroelastic materials under the action of concentrated magnetoelectromechanical loads on the crack faces is considered. The open part of the crack is assumed to be magnetically impermeable and electrically permeable. The Dirichlet-Riemann boundary value problem is formulated and solved analytically. Stress, magnetic induction and electrical displacement intensity factors as well as energy release rate are thus found in analytical forms. Analytical expressions for the contact zone length have been derived. Some numerical results are presented and compared with those based on the other crack surface conditions. It is shown clearly that the location and magnitude of the applied loads could significantly affect the contact zone length, the stress intensity factor and the energy release rate.
基金supported by the National Natural Science Foundation of China(Grant No.51279189)the National Hi-Tech Research and Development Program of China("863"Project)(Grant No.2008AA09Z309)China Scholarship Council and University of Aberdeen
文摘This study proposes a new approach in which an impermeable plate is placed under the pipeline to prevent the local scour around the pipeline.In order to understand the performance of this approach,the finite volume method(FVM) and volume of fluid(VOF) method are adopted to simulate the flow field around the pipeline.The pressure distribution along the sandy bed surface is obtained by considering the variation of water surface.Furthermore,the effects of water depth,unidirectional and bidirectional impermeable plates on pressure difference are discussed.The seepage flow field of sandy bed near underwater pipeline is numerically simulated using the laminar and porous media model.On this basis,the effect of the impermeable plate length on hydraulic gradient is investigated and the critical length of impermeable plate is obtained.The simulated results show that when the water depth is smaller than 5.00D(D is the diameter of pipeline),the effect of the water depth on the pressure difference is remarkable.The pressure differences between two endpoints of both the unidirectional and bidirectional plates decrease with the increase of the plate length.The variations of the pressure differences for both the unidirectional and bidirectional plates are similar.With the increase of plate length,the hydraulic gradient decreases and the piping at the seepage exit is avoided effectively as long as it reaches a certain length.Such a critical length of the plate decreases with the increase of the water depth.When water depth is larger than 4.00D,the effect of the water depth on the critical length is small.For the same water depth,the critical length of impermeable plate increases with the increase of the dimensionless flow parameter.Numerical simulation results are in good agreement with the available experimental measurements.
