Debris flows are one of the common natural hazards in mountainous areas.They often cause devastating damage to the lives and property of local people.The sabo dam construction along a debris flow valley is considered ...Debris flows are one of the common natural hazards in mountainous areas.They often cause devastating damage to the lives and property of local people.The sabo dam construction along a debris flow valley is considered to be a useful method for hazard mitigation.Previous work has concentrated on the different types of sabo dams such as close-type sabo dam,open-type sabo dam.However,little attention has been paid to the spillway structure of sabo dam.In the paper,a new type of spillway structure with lateral contraction was proposed.Debris flow patterns under four different spillway structures were investigated.The projection theory was employed to predict trajectory of debris flow out from the spillway and to estimate the incident angle and terminal velocity before it plunged into the scour hole behind the sabo dam.The results indicated that the estimated data were in good agreement with the experimental ones.The discrepancy between the estimated and experimental values of main parameters remained below 21.82%(relative error).Additionally,the effects of debris flow scales under different spillway structures were considered to study the scour law.Although the debris flow pattern and scour law behind the sabo dam under different operating conditions was analyzed in this paper,further study on the scour mechanism andthe maximum scour depth estimation based on scour theory is still required in the future.展开更多
In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including ...In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including 17 tests was conducted to estimate the variation of the discharge coefficient due to variation of the longitudinal slope. It was shown that the discharge coefficient is significantly increasing with the increase of the slope by more than 90% or 75% and 80% or 70% for weir and spillway in case of excluding or including the approach velocity head, respectively. Also, CFD （computational fluid dynamics） with a help of Comsol-multyphsics program was used to simulate the problem. The program explained that the linear distribution of the hydraulic pressure changes to a non-linear distribution as the longitudinal slope is considered. Consequently, the values of the discharge coefficient are also affected.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.51209195)Foundation of Key Laboratory of Mountain Hazards and Earth Surface Process,Chinese Academy of Sciences,Science and Technology Service Network Initiative of Chinese Academy of Sciences (Grant No.KFJ-EW-STS-094)the Youth Foundation of the Institute of Mountain Hazards and Environment,CAS (Grant No.SDS-QN-1302)
文摘Debris flows are one of the common natural hazards in mountainous areas.They often cause devastating damage to the lives and property of local people.The sabo dam construction along a debris flow valley is considered to be a useful method for hazard mitigation.Previous work has concentrated on the different types of sabo dams such as close-type sabo dam,open-type sabo dam.However,little attention has been paid to the spillway structure of sabo dam.In the paper,a new type of spillway structure with lateral contraction was proposed.Debris flow patterns under four different spillway structures were investigated.The projection theory was employed to predict trajectory of debris flow out from the spillway and to estimate the incident angle and terminal velocity before it plunged into the scour hole behind the sabo dam.The results indicated that the estimated data were in good agreement with the experimental ones.The discrepancy between the estimated and experimental values of main parameters remained below 21.82%(relative error).Additionally,the effects of debris flow scales under different spillway structures were considered to study the scour law.Although the debris flow pattern and scour law behind the sabo dam under different operating conditions was analyzed in this paper,further study on the scour mechanism andthe maximum scour depth estimation based on scour theory is still required in the future.
文摘In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including 17 tests was conducted to estimate the variation of the discharge coefficient due to variation of the longitudinal slope. It was shown that the discharge coefficient is significantly increasing with the increase of the slope by more than 90% or 75% and 80% or 70% for weir and spillway in case of excluding or including the approach velocity head, respectively. Also, CFD （computational fluid dynamics） with a help of Comsol-multyphsics program was used to simulate the problem. The program explained that the linear distribution of the hydraulic pressure changes to a non-linear distribution as the longitudinal slope is considered. Consequently, the values of the discharge coefficient are also affected.
