The joint of clay core-wall and concrete cut-off wall is one of the weakest parts in high earth and rockftll dams.A kind of highly plastic clay is always fixed on the joint to fit the large shear deformation between c...The joint of clay core-wall and concrete cut-off wall is one of the weakest parts in high earth and rockftll dams.A kind of highly plastic clay is always fixed on the joint to fit the large shear deformation between clay core-wall and concrete cut-offwall,so the hydro-mechanical coupling mechanisms on the joint under high stress,high hydraulic gradient,and large shear deformation are of great importance for the evaluation of dam safety.The hydro-mechanical coupling characteristics of the joint of the highly plastic clay and the concrete cut-off wall in a high earth and rockfill dam in China were studied by using a newly designed soil-structure contact erosion apparatus.The experimental results indicate that：1） Shear failure on the joint is due to the hydro-mechanical coupling effect of stress and seepage failure.The seepage failure will induce the final shear failure when the ratio of deviatoric stress to confining pressure is within 1.0-1.2; 2） A negative exponential permeability empirical model for the joint denoted by a newly defined principal stress function,which considers the coupling effect of confining pressure and axial pressure on the permeability,is established based on hydro-mechanical coupling experiments.3） The variation of the settlement before and after seepage failure is very different.The settlement before seepage failure changes very slowly,while it increases significantly after the seepage failure.4） The stress-strain relationship is of a strain softening type.5） Flow along the joint still follows Darcian flow rule.The results will provide an important theoretical basis for the further evaluation on the safety of the high earth and rockfill dam.展开更多
Hongxing reservoir was constructed on the floodplain of Hulan River in Heilongjiang. The geological problem of the reservoir is the seepage of the dam base and its related seepage stability. The leakage of the reservo...Hongxing reservoir was constructed on the floodplain of Hulan River in Heilongjiang. The geological problem of the reservoir is the seepage of the dam base and its related seepage stability. The leakage of the reservoir is caused by the water head differences between the upstream and downstream of the dam. Severe seepage could decrease the engineering benefits of the reservoir. Moreover,infiltration function of water will influence the safety of the dam. Through the analysis on the granule constitute and the formation of the dam base,the types of the seepage failure apt to happen were defined and the anti-infiltration and the permissible depression ratio were determined. Using the numerical simulation software GMS,the two-dimension numerical modeling has been carried out to analyze the seepage field of the reservoir. Through the two conditions modeling with concrete impervious wall and no concrete impervious wall,the largest flow rate,single-wide seepage discharge and the max infiltration gradient of the dam base were calculated. According to the permeable depression ratio of the dam base,the seepage stability of Hongxing reservoir dam base was analyzed.展开更多
Combined with a proposed homogeneous earth dam in deep cladding foundation, Duncan E-B model is applied to simulate dam-filled material, apply to three-dimensional nonlinear finite element method, attain the stress-st...Combined with a proposed homogeneous earth dam in deep cladding foundation, Duncan E-B model is applied to simulate dam-filled material, apply to three-dimensional nonlinear finite element method, attain the stress-strain distribution and alteration in concrete cutoff wall in completion and water storage periods, analysis the stress state in the contact element between concrete cutoff wall and cladding foundation, provide the corresponding measures. The calculation results show that the design of concrete cutoff wall and homogeneous earth dam is reasonable.展开更多
基金Projects(51009053,51079039)supported by the National Natural Science Foundation of ChinaProject(20100094120004)supported by the Doctoral Program of Higher Education of China
文摘The joint of clay core-wall and concrete cut-off wall is one of the weakest parts in high earth and rockftll dams.A kind of highly plastic clay is always fixed on the joint to fit the large shear deformation between clay core-wall and concrete cut-offwall,so the hydro-mechanical coupling mechanisms on the joint under high stress,high hydraulic gradient,and large shear deformation are of great importance for the evaluation of dam safety.The hydro-mechanical coupling characteristics of the joint of the highly plastic clay and the concrete cut-off wall in a high earth and rockfill dam in China were studied by using a newly designed soil-structure contact erosion apparatus.The experimental results indicate that：1） Shear failure on the joint is due to the hydro-mechanical coupling effect of stress and seepage failure.The seepage failure will induce the final shear failure when the ratio of deviatoric stress to confining pressure is within 1.0-1.2; 2） A negative exponential permeability empirical model for the joint denoted by a newly defined principal stress function,which considers the coupling effect of confining pressure and axial pressure on the permeability,is established based on hydro-mechanical coupling experiments.3） The variation of the settlement before and after seepage failure is very different.The settlement before seepage failure changes very slowly,while it increases significantly after the seepage failure.4） The stress-strain relationship is of a strain softening type.5） Flow along the joint still follows Darcian flow rule.The results will provide an important theoretical basis for the further evaluation on the safety of the high earth and rockfill dam.
文摘Hongxing reservoir was constructed on the floodplain of Hulan River in Heilongjiang. The geological problem of the reservoir is the seepage of the dam base and its related seepage stability. The leakage of the reservoir is caused by the water head differences between the upstream and downstream of the dam. Severe seepage could decrease the engineering benefits of the reservoir. Moreover,infiltration function of water will influence the safety of the dam. Through the analysis on the granule constitute and the formation of the dam base,the types of the seepage failure apt to happen were defined and the anti-infiltration and the permissible depression ratio were determined. Using the numerical simulation software GMS,the two-dimension numerical modeling has been carried out to analyze the seepage field of the reservoir. Through the two conditions modeling with concrete impervious wall and no concrete impervious wall,the largest flow rate,single-wide seepage discharge and the max infiltration gradient of the dam base were calculated. According to the permeable depression ratio of the dam base,the seepage stability of Hongxing reservoir dam base was analyzed.
文摘Combined with a proposed homogeneous earth dam in deep cladding foundation, Duncan E-B model is applied to simulate dam-filled material, apply to three-dimensional nonlinear finite element method, attain the stress-strain distribution and alteration in concrete cutoff wall in completion and water storage periods, analysis the stress state in the contact element between concrete cutoff wall and cladding foundation, provide the corresponding measures. The calculation results show that the design of concrete cutoff wall and homogeneous earth dam is reasonable.
