A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice fl...A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice flow and two-dimensional(2D)shallow water equations(SWE)are solved to simulate dam break flows at different breaching stages.Erosion rates of different soils with different construction compaction efforts are calculated using corresponding erosion formulae.The dam's real shape,soil properties,and surrounding area are programmed.Large outer 2D-SWE grids are used to control upstream and downstream hydraulic conditions and control the boundary conditions of orifice flow,and inner 2D-SWE flow is used to scour soil and perform force/moment equilibrium analyses.This model is validated using the European Commission IMPACT(Investigation of Extreme Flood Processes and Uncertainty)Test#5 in Norway,Teton Dam failure in Idaho,USA,and Quail Creek Dike failure in Utah,USA.All calculated peak outflows are within 10%errors of observed values.Simulation results show that,for a V-shaped dam like Teton Dam,a piping breach location at the abutment tends to result in a smaller peak breach outflow than the piping breach location at the dam's center;and if Teton Dam had broken from its center for internal erosion,a peak outflow of 117851 m'/s,which is 81%larger than the peak outflow of 65120 m3/s released from its right abutment,would have been released from Teton Dam.A lower piping inlet elevation tends to cause a faster/earlier piping breach than a higher piping inlet elevation.展开更多
In this study,the research progress of trenchless piping technology for pipes with a large diameter was reviewed.The geological conditions of the sandbar in Xiangyang were taken into account in this study.This paper h...In this study,the research progress of trenchless piping technology for pipes with a large diameter was reviewed.The geological conditions of the sandbar in Xiangyang were taken into account in this study.This paper highlights the construction process management of the pipeline network project in Yuliangzhou Starting Area of Xiangyang City.Research was carried out in the aspects of optimizing mud ratio,controlling pipeline elevations,pipeline welding,and trenchless pipeline construction in limited spaces,stable support during pit excavation,and controlling the spacing between the junctions of two pipe segments.The research resulted in excellent outcomes and ensured safe construction,and the quality requirements were also met.展开更多
文摘A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice flow and two-dimensional(2D)shallow water equations(SWE)are solved to simulate dam break flows at different breaching stages.Erosion rates of different soils with different construction compaction efforts are calculated using corresponding erosion formulae.The dam's real shape,soil properties,and surrounding area are programmed.Large outer 2D-SWE grids are used to control upstream and downstream hydraulic conditions and control the boundary conditions of orifice flow,and inner 2D-SWE flow is used to scour soil and perform force/moment equilibrium analyses.This model is validated using the European Commission IMPACT(Investigation of Extreme Flood Processes and Uncertainty)Test#5 in Norway,Teton Dam failure in Idaho,USA,and Quail Creek Dike failure in Utah,USA.All calculated peak outflows are within 10%errors of observed values.Simulation results show that,for a V-shaped dam like Teton Dam,a piping breach location at the abutment tends to result in a smaller peak breach outflow than the piping breach location at the dam's center;and if Teton Dam had broken from its center for internal erosion,a peak outflow of 117851 m'/s,which is 81%larger than the peak outflow of 65120 m3/s released from its right abutment,would have been released from Teton Dam.A lower piping inlet elevation tends to cause a faster/earlier piping breach than a higher piping inlet elevation.
文摘In this study,the research progress of trenchless piping technology for pipes with a large diameter was reviewed.The geological conditions of the sandbar in Xiangyang were taken into account in this study.This paper highlights the construction process management of the pipeline network project in Yuliangzhou Starting Area of Xiangyang City.Research was carried out in the aspects of optimizing mud ratio,controlling pipeline elevations,pipeline welding,and trenchless pipeline construction in limited spaces,stable support during pit excavation,and controlling the spacing between the junctions of two pipe segments.The research resulted in excellent outcomes and ensured safe construction,and the quality requirements were also met.
