The cave is of great importance for the storage of equipment and to avoid having workers in the tunnel,but it changes the tunnel section,leads to a change of slipstream and affects the safety of trains and workers.The...The cave is of great importance for the storage of equipment and to avoid having workers in the tunnel,but it changes the tunnel section,leads to a change of slipstream and affects the safety of trains and workers.The Re-normalization group(RNG)k-εturbulence method is used to investigate the slipstream induced by a single train passing through a double-track tunnel at 350 km/h.The slipstream in a tunnel with and without a cave is compared.The slipstream components in three directions are reported comprehensively.The results show that the existence of a cave changes the slipstream at the tail of the train.At measurement points before and after the train passes the cave,the intensity of the slipstream at the tail ismitigated;as the train passes the cave,the tail slipstream is enhanced to a certain extent.With increasing lateral distance,the peak value of the slipstream with a cave decreases faster than that without a cave.These findings suggest that the presence of a cave mitigates the slipstream intensity,but special attention should be paid to the design of ancillary facilities,especially their relative location.展开更多
Balance of the groundwater and ecology is crucial for controlled discharge.However,regarding the segments of tunnel boring machines(TBMs)under high water pressure,the stability of the lining structure is often reduced...Balance of the groundwater and ecology is crucial for controlled discharge.However,regarding the segments of tunnel boring machines(TBMs)under high water pressure,the stability of the lining structure is often reduced by excessive drain holes required to achieve this balance.The large discharge of pinholes can easily have severe consequences,such as the lowering of the groundwater table,drying of springs,and vegetation wilting.Thus,in this study,according to the fluid-structure coupling theory,a new drainage design for TBM segments was developed by considering a mountain tunnel subject to a high water pressure as a case study.The evolution characteristics,including the external water pressure of the lining,discharge volume of the segment,and groundwater-table drawdown,were investigated via numerical modeling with drain holes and pinholes.The results indicated that the optimal design parameters of drainage segments for the project case were as follows:a circumferential spacing angle and longitudinal number on one side of a single ring of 51°and 2,respectively,for the drain holes and an inclination angle and length of 46.41°and 0.25 times the grouting thickness,respectively,for the pin holes.展开更多
基金the High-Speed Train Research Center of Central South University,China.Thiswork was supported by the National Key Research and Development Program of China(Grant No.2020YFA0710903-01)the Graduate Student Independent Innovation Project of Hunan Province(Grant No.CX20200196).
文摘The cave is of great importance for the storage of equipment and to avoid having workers in the tunnel,but it changes the tunnel section,leads to a change of slipstream and affects the safety of trains and workers.The Re-normalization group(RNG)k-εturbulence method is used to investigate the slipstream induced by a single train passing through a double-track tunnel at 350 km/h.The slipstream in a tunnel with and without a cave is compared.The slipstream components in three directions are reported comprehensively.The results show that the existence of a cave changes the slipstream at the tail of the train.At measurement points before and after the train passes the cave,the intensity of the slipstream at the tail ismitigated;as the train passes the cave,the tail slipstream is enhanced to a certain extent.With increasing lateral distance,the peak value of the slipstream with a cave decreases faster than that without a cave.These findings suggest that the presence of a cave mitigates the slipstream intensity,but special attention should be paid to the design of ancillary facilities,especially their relative location.
基金the National Natural Science Foundation of China(Grant No.41972276)the Natural Science Foundation of Fujian Province(No.2020J06013)the"Foal Eagle Program"Youth Top-notch Talent Project of Fujian Province(No.00387088),The financial support is gratefully acknowledged.
文摘Balance of the groundwater and ecology is crucial for controlled discharge.However,regarding the segments of tunnel boring machines(TBMs)under high water pressure,the stability of the lining structure is often reduced by excessive drain holes required to achieve this balance.The large discharge of pinholes can easily have severe consequences,such as the lowering of the groundwater table,drying of springs,and vegetation wilting.Thus,in this study,according to the fluid-structure coupling theory,a new drainage design for TBM segments was developed by considering a mountain tunnel subject to a high water pressure as a case study.The evolution characteristics,including the external water pressure of the lining,discharge volume of the segment,and groundwater-table drawdown,were investigated via numerical modeling with drain holes and pinholes.The results indicated that the optimal design parameters of drainage segments for the project case were as follows:a circumferential spacing angle and longitudinal number on one side of a single ring of 51°and 2,respectively,for the drain holes and an inclination angle and length of 46.41°and 0.25 times the grouting thickness,respectively,for the pin holes.
