The characteristics of a new type of drainage channel with staggered indented sills for controlling debris flows were studied. The intermediate fluid in the non-viscous debris flow exhibited a helical movement, wherea...The characteristics of a new type of drainage channel with staggered indented sills for controlling debris flows were studied. The intermediate fluid in the non-viscous debris flow exhibited a helical movement, whereas the fluid near the sidewall had a stop-start movement pattern; the viscous debris flow exhibited a stable structure between the indented sills. The experimental results indicate that the mean velocity of the debris flow increased with increasing channel gradients, and the debris flow velocity was slightly affected by the angle of the sills. The average velocity of the non-viscous debris flow increased in the range of(0.5–1.5) interval between the indented sills, whereas the average velocity of the viscous debris flow increased initially and then decreased in the range of(0.75–1.25) interval between the indented sills. The depth of the non-viscous debris flow tended to gradually increase as the channel gradients increased, whereas the depth of the viscous debris flow gradually decreased as the channel gradients increased. When the discharge of the debris flow was constant, the angle and the interval between the indented sills had a slight effect on the depth of the viscous debris flow, whereas the depth of the non-viscous debris flow exhibited a different trend, as the sill angles and intervals were varied.展开更多
In this paper, the motion and acceleration process, as well as the mechanism of a high speed and long run landslide are investigated by adopting high speed ring shear test and taking the landslide occurred at Yigong R...In this paper, the motion and acceleration process, as well as the mechanism of a high speed and long run landslide are investigated by adopting high speed ring shear test and taking the landslide occurred at Yigong River in Bomi, Tibet on April 9, 2000 as the background. According to the motion characteristics of high-speed and long distance motion landside, the mechanism is studied under different conditions such as shear speed, consolidated drained and consolidated undrained status. Results show that high speed shearing process hinders and delays the dissipation of pore pressure, and drives pore water migrating to shear zone slowly. Both of water content and fine particle content at shear zone are obviously higher than those in other layers; and soil liquefaction occurs at shear zone in the saturated consolidated undrained ring shear tests. The effective internal friction angle of the consolidated undrained soil is much lower than that of the consolidated drained soil under ring shearing. The results also indicate that the shearing speed affecting the strength of soil to some extent. The higher the ring shearing speed is, the lower the strength of soil is. This investigation provides a preliminary interpretation of the mechanism of the motion and acceleration process of the Yigong landslide, occurred in Tibet in 2000.展开更多
The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical s...The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.展开更多
基金sponsored by the Key Deployment Project of Chinese Academy of Sciences(Grant No.KZZD-EW-05-01)the National Science Foundation of China(Grant No.41072270)
文摘The characteristics of a new type of drainage channel with staggered indented sills for controlling debris flows were studied. The intermediate fluid in the non-viscous debris flow exhibited a helical movement, whereas the fluid near the sidewall had a stop-start movement pattern; the viscous debris flow exhibited a stable structure between the indented sills. The experimental results indicate that the mean velocity of the debris flow increased with increasing channel gradients, and the debris flow velocity was slightly affected by the angle of the sills. The average velocity of the non-viscous debris flow increased in the range of(0.5–1.5) interval between the indented sills, whereas the average velocity of the viscous debris flow increased initially and then decreased in the range of(0.75–1.25) interval between the indented sills. The depth of the non-viscous debris flow tended to gradually increase as the channel gradients increased, whereas the depth of the viscous debris flow gradually decreased as the channel gradients increased. When the discharge of the debris flow was constant, the angle and the interval between the indented sills had a slight effect on the depth of the viscous debris flow, whereas the depth of the non-viscous debris flow exhibited a different trend, as the sill angles and intervals were varied.
基金financial aided by the National Basic Research Program of China (2012CB026103)the National Natural Science Foundation of China (Grant Nos. 41172283, 41372313)
文摘In this paper, the motion and acceleration process, as well as the mechanism of a high speed and long run landslide are investigated by adopting high speed ring shear test and taking the landslide occurred at Yigong River in Bomi, Tibet on April 9, 2000 as the background. According to the motion characteristics of high-speed and long distance motion landside, the mechanism is studied under different conditions such as shear speed, consolidated drained and consolidated undrained status. Results show that high speed shearing process hinders and delays the dissipation of pore pressure, and drives pore water migrating to shear zone slowly. Both of water content and fine particle content at shear zone are obviously higher than those in other layers; and soil liquefaction occurs at shear zone in the saturated consolidated undrained ring shear tests. The effective internal friction angle of the consolidated undrained soil is much lower than that of the consolidated drained soil under ring shearing. The results also indicate that the shearing speed affecting the strength of soil to some extent. The higher the ring shearing speed is, the lower the strength of soil is. This investigation provides a preliminary interpretation of the mechanism of the motion and acceleration process of the Yigong landslide, occurred in Tibet in 2000.
基金supported by Key Laboratory for National Defence of Underwater Observing and Control Technology fund number 9140c2603100805
文摘The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.
