Multiple-Mode Transient Inflow Impact with Entrapped Air Pocket in Deep Storage Tunnel Systems
As an effective waterlogging control measure,deep storage tunnel systems have air pocket retention during the inflows of multiple shafts,causing issues like pressure surges and threatening the safety of system operation.According to the deep storage tunnel project of Suzhou section,a dual-shaft and single-tunnel system model is constructed.Numerical simulations are carried out with computational fluid dynamics methods and verified by water filling experiments,while the pressure surges of entrapped air pocket under different inflow conditions are analyzed and the variation law is summarized.The results show that under the design inflow condition,the maximum pressure of 3.5%entrapped air pocket can reach 35.36 m,which is 1.77 times of the static pressure of the shaft at the control water level.When the total inflow of shafts is constant,the flow distribution has little effect on the pressure.With symmetrical inflow,the extreme pressure is the largest,which is 3%and 6%larger than the unilateral inflow respectively.In case of symmetrical inflow,with the increase of total inflow,the maximum pressure of air pocket first increases and then stabilizes,and compared with that of 29 m3/s total inflow,it increases by about 30%,corresponding to the total inflow of 116 m3/s.
transientnumerical simulationdeep storage tunnel systementrapped air pocket