Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters....Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters. The principle on establishing the coupling model of seepage_field and stress_field for RCCD was presented. A 3_D Finite Element Method(FEM) program was developed. Study shows that such parameters as the thickness of construction interfaces,the elastic ratio and the (Poisson's) ratio obtained by tests and theoretical analysis are more reasonable, the coupling model of seepage_field and stress_field for RCCD may indicate the coupling effect between the two fields scientifically, and the developed 3_D FEM program can reflect the effect of the construction interfaces more adequately. According to the study, many scientific opinions are given both to analyze the influence of the construction interfaces to the (dam's) characteristic, and to reveal the interaction between the stress_field and the seepage_field.展开更多
During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Krigin...During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Kriging temperature interpolation is proposed.Based on dam site monitoring data of distributed optical fiber,the results indicated that the proposed restructuring method can be applied to effectively and quickly obtain 2D real thermal field.The evolution law of thermal field in early ages and temperature differences of concrete blocks based on the thermal field data are obtained.It also can be concluded that the proposed restructuring method could help obtain accurate and reliable restructuring monitoring data.展开更多
振冲碎石桩是软弱土坝基重要的加固手段,在实际的工程实践中,振冲碎石桩加固手段对于软弱坝基的处理是否有效需要基于现场试验进行检测。针对非洲卢旺达Nyabarongo II HPP工程的坝基振冲碎石桩加固措施难题,在国内选址了地质条件相似的...振冲碎石桩是软弱土坝基重要的加固手段,在实际的工程实践中,振冲碎石桩加固手段对于软弱坝基的处理是否有效需要基于现场试验进行检测。针对非洲卢旺达Nyabarongo II HPP工程的坝基振冲碎石桩加固措施难题,在国内选址了地质条件相似的温州仙湖试验区进行振冲碎石桩的现场试验,验证了振冲碎石桩加固深厚软土层的有效性。采用孔压静力触探试验、十字剪切板试验、动力触探试验、载荷试验检测振冲碎石桩的加固效果和地基承载力。相关研究可丰富软弱土坝基的振冲碎石桩施工处理工艺,为后续类似工程加固实践提供参考。展开更多
During reservoir operation,the erosion effects of groundwater change the porosity and permeability of the dam curtain,causing changes to the seepage field.To understand where the changes take place and to what degree ...During reservoir operation,the erosion effects of groundwater change the porosity and permeability of the dam curtain,causing changes to the seepage field.To understand where the changes take place and to what degree the porosity and permeability change,a multi-field coupling model was built and solved.The model takes into account seepage,solution concentration,and solid structure.The model was validated using uplift pressure monitoring data.Then,the variations in curtain porosity,seepage flow,and loss quantity of Ca(OH)2 were calculated.The key time nodes were obtained through curve fitting of the variation of seepage flow with the BiDoseResp function.The results showed that the model could reflect the attenuation trend of curtain performance well.The process and position of the erosion were not homogeneous.Although erosion mainly occurred at the top and bottom of the curtain,it was most developed at the top.The erosion effects developed slowly during the early stage,much fast during the middle and late stages,and culminated in complete dissolution.The model results and the daily monitoring data can provide a scientific basis for the safe operation and management of reservoirs.展开更多
In the water modeling experiments, three cases were considered, i. e, , a bare tundish, a tundish equipped with a turbulence inhibitor, and a rectangular tundish equipped with weirs （dams） and a turbulence inhibitor...In the water modeling experiments, three cases were considered, i. e, , a bare tundish, a tundish equipped with a turbulence inhibitor, and a rectangular tundish equipped with weirs （dams） and a turbulence inhibitor. Comparing the RTD curves, inclusion separation, and the result of the streamline experiment, it can be found that the tundish equipped with weirs （dams） and a turbulence inhibitor has a great effect on the flow field and the inclusion separation when compared with the sole use or no use of the turbulent inhibitor or weirs （dams）. In addition, the enlargement of the distance between the weir and dam will result in a better effect when the tundish equipped with weirs （dam） and a turbulence inhibitor was used.展开更多
One of the main concerns in using commercial software for finite element analyses of dam-foundation-reservoir systems is that the simplifying assumptions of the massless foundation are unreliable. In this study, an ap...One of the main concerns in using commercial software for finite element analyses of dam-foundation-reservoir systems is that the simplifying assumptions of the massless foundation are unreliable. In this study, an appropriate direct finite element method is introduced for simulating the mass, radiation damping and wave propagation effect in foundations of damfoundation-reservoir systems using commercial software ABAQUS. The free-field boundary condition is used for modeling the semi-infinite foundation and radiation damping, which is not a built-in boundary condition in most of the available commercial software for finite element analysis of structures such as ANSYS or ABAQUS and thus needs to be implemented differently. The different mechanism for modeling of the foundation, earthquake input and far-field boundary condition is described. Implementation of the free-field boundary condition in finite element software is verified by comparing it with analytical results. To investigation the feasibility of the proposed method in dam-foundation-reservoir system analysis, a series of analyses is accomplished in a variety of cases and the obtained results are compared with the substructure method by using the EAGD-84 program. Finally, the massed and massless foundation results are compared and it is concluded that the massless foundation approach leads to the overestimation of the displacements and stresses within the dam body.展开更多
文摘Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters. The principle on establishing the coupling model of seepage_field and stress_field for RCCD was presented. A 3_D Finite Element Method(FEM) program was developed. Study shows that such parameters as the thickness of construction interfaces,the elastic ratio and the (Poisson's) ratio obtained by tests and theoretical analysis are more reasonable, the coupling model of seepage_field and stress_field for RCCD may indicate the coupling effect between the two fields scientifically, and the developed 3_D FEM program can reflect the effect of the construction interfaces more adequately. According to the study, many scientific opinions are given both to analyze the influence of the construction interfaces to the (dam's) characteristic, and to reveal the interaction between the stress_field and the seepage_field.
基金supported by National Basic Research Program of China(973 Program)Grant No.2011CB013503China Three Gorges Corporation research project(Contract number:WDD/0490)
文摘During concrete dam construction,concrete temperature monitoring and control is key to ensuring dam concrete quality and construction safety.In this study,a 2D thermal field restructuring method relating to the Kriging temperature interpolation is proposed.Based on dam site monitoring data of distributed optical fiber,the results indicated that the proposed restructuring method can be applied to effectively and quickly obtain 2D real thermal field.The evolution law of thermal field in early ages and temperature differences of concrete blocks based on the thermal field data are obtained.It also can be concluded that the proposed restructuring method could help obtain accurate and reliable restructuring monitoring data.
文摘振冲碎石桩是软弱土坝基重要的加固手段,在实际的工程实践中,振冲碎石桩加固手段对于软弱坝基的处理是否有效需要基于现场试验进行检测。针对非洲卢旺达Nyabarongo II HPP工程的坝基振冲碎石桩加固措施难题,在国内选址了地质条件相似的温州仙湖试验区进行振冲碎石桩的现场试验,验证了振冲碎石桩加固深厚软土层的有效性。采用孔压静力触探试验、十字剪切板试验、动力触探试验、载荷试验检测振冲碎石桩的加固效果和地基承载力。相关研究可丰富软弱土坝基的振冲碎石桩施工处理工艺,为后续类似工程加固实践提供参考。
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.51609150)the National Key Research and Development Program of China(Grant No.2018YFC0407103)the National Natural Science Foundation of China(Grant No.51779155)
文摘During reservoir operation,the erosion effects of groundwater change the porosity and permeability of the dam curtain,causing changes to the seepage field.To understand where the changes take place and to what degree the porosity and permeability change,a multi-field coupling model was built and solved.The model takes into account seepage,solution concentration,and solid structure.The model was validated using uplift pressure monitoring data.Then,the variations in curtain porosity,seepage flow,and loss quantity of Ca(OH)2 were calculated.The key time nodes were obtained through curve fitting of the variation of seepage flow with the BiDoseResp function.The results showed that the model could reflect the attenuation trend of curtain performance well.The process and position of the erosion were not homogeneous.Although erosion mainly occurred at the top and bottom of the curtain,it was most developed at the top.The erosion effects developed slowly during the early stage,much fast during the middle and late stages,and culminated in complete dissolution.The model results and the daily monitoring data can provide a scientific basis for the safe operation and management of reservoirs.
文摘In the water modeling experiments, three cases were considered, i. e, , a bare tundish, a tundish equipped with a turbulence inhibitor, and a rectangular tundish equipped with weirs （dams） and a turbulence inhibitor. Comparing the RTD curves, inclusion separation, and the result of the streamline experiment, it can be found that the tundish equipped with weirs （dams） and a turbulence inhibitor has a great effect on the flow field and the inclusion separation when compared with the sole use or no use of the turbulent inhibitor or weirs （dams）. In addition, the enlargement of the distance between the weir and dam will result in a better effect when the tundish equipped with weirs （dam） and a turbulence inhibitor was used.
文摘One of the main concerns in using commercial software for finite element analyses of dam-foundation-reservoir systems is that the simplifying assumptions of the massless foundation are unreliable. In this study, an appropriate direct finite element method is introduced for simulating the mass, radiation damping and wave propagation effect in foundations of damfoundation-reservoir systems using commercial software ABAQUS. The free-field boundary condition is used for modeling the semi-infinite foundation and radiation damping, which is not a built-in boundary condition in most of the available commercial software for finite element analysis of structures such as ANSYS or ABAQUS and thus needs to be implemented differently. The different mechanism for modeling of the foundation, earthquake input and far-field boundary condition is described. Implementation of the free-field boundary condition in finite element software is verified by comparing it with analytical results. To investigation the feasibility of the proposed method in dam-foundation-reservoir system analysis, a series of analyses is accomplished in a variety of cases and the obtained results are compared with the substructure method by using the EAGD-84 program. Finally, the massed and massless foundation results are compared and it is concluded that the massless foundation approach leads to the overestimation of the displacements and stresses within the dam body.
