Benggang is a special type of soil erosion,which widely distributes in the granite residual soil area of southern China.Owing to the influence of local climate and topography,shallow cracks having different morphologi...Benggang is a special type of soil erosion,which widely distributes in the granite residual soil area of southern China.Owing to the influence of local climate and topography,shallow cracks having different morphological characteristics are easily formed on the slope surface.These shallow cracks damage the surface structure of the slope and accelerate water infiltration,making it easier to cause severe soil and water loss.However,the mechanism of Benggang process is still unclear,especially for slopes with different shallow crack characteristics.In this study,granite residual soil was collected from Benngang erosion area in Yudu County,Jiangxi Province,southern China.Three experimental treatments with slope surface crack rates of 0%,5.23%,and 11.70%were performed.Simultaneous monitoring of moisture content and soil temperature in the slope were carried out during rainfall,and the characteristics of preferential flow were monitored with different crack rates.Morphological development and evolution process of Benggang with different crack rates were studied.Results show that high surface crack rate of the shallow surface on the slope accelerated the development of shallow gully erosion,leading to premature occurrence of gully erosion.As the shallow crack rate increased from 0%to 5.23%and 11.70%,the width-depth ratio of the rills at the slope bottom increased from 0.69 to 1.02 and 1.16,respectively.At the same time,a correlation between moisture and temperature data was observed for the process of water-heat coupled migration.The upper soil temperature of slope decreased quickly due to preferential flow.The simultaneous monitoring of soil moisture and temperature can effectively track preferential flow and indicate the water movement.Temperature data was a more sensitive indicator of the seepage paths of preferential flow compared to moisture data.展开更多
The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue cr...The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.展开更多
In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction ofthe explosion stress wave and blasting effect. Herein, we examine the explosion wave fie...In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction ofthe explosion stress wave and blasting effect. Herein, we examine the explosion wave field and rock breaking effect in terms of shockwave collision, stress change of the blast hole wall in the collision zone, and crack propagation in the collision zone. The produced shockwave on the collision surface has an intensity surpassing the sum of the intensities of the two colliding explosion shock waves. At the collisionlocation, the kinetic energy is transformed into potential energy with a reduction in particle velocity at the wave front and the wavefront pressure increases. The expansion form of the superposed shock wave is dumbbell-shaped, the shock wave velocity in the collisionarea is greater than the radial shock wave velocity, and the average propagation angle of the explosion shock waves is approximately 60°.Accordingly, a fitted relationship between blast hole wall stress and explosion wave propagation angle in the superposition area is plotted.Under the experimental conditions, the superimposed explosion wave stress of the blast hole wall is approximately 1.73 times the singleexplosionwave incident stress. The results of the model test and numerical simulations reveal that large-scale radial fracture cracks weregenerated on the blast hole wall in the superimposed area, and the width of the crack increased. The width of the large-scale radial fracturecracks formed by a strong impact is approximately 5% of the blast hole length. According to the characteristics of blast hole wallcompression, the mean peak pressures of the strongly superimposed area are approximately 1.48 and 1.84 times those of the weakly superimposedand nonsuperimposed areas, respectively.展开更多
基金funded by the National Natural Science Foundation of China(No.41962015)。
文摘Benggang is a special type of soil erosion,which widely distributes in the granite residual soil area of southern China.Owing to the influence of local climate and topography,shallow cracks having different morphological characteristics are easily formed on the slope surface.These shallow cracks damage the surface structure of the slope and accelerate water infiltration,making it easier to cause severe soil and water loss.However,the mechanism of Benggang process is still unclear,especially for slopes with different shallow crack characteristics.In this study,granite residual soil was collected from Benngang erosion area in Yudu County,Jiangxi Province,southern China.Three experimental treatments with slope surface crack rates of 0%,5.23%,and 11.70%were performed.Simultaneous monitoring of moisture content and soil temperature in the slope were carried out during rainfall,and the characteristics of preferential flow were monitored with different crack rates.Morphological development and evolution process of Benggang with different crack rates were studied.Results show that high surface crack rate of the shallow surface on the slope accelerated the development of shallow gully erosion,leading to premature occurrence of gully erosion.As the shallow crack rate increased from 0%to 5.23%and 11.70%,the width-depth ratio of the rills at the slope bottom increased from 0.69 to 1.02 and 1.16,respectively.At the same time,a correlation between moisture and temperature data was observed for the process of water-heat coupled migration.The upper soil temperature of slope decreased quickly due to preferential flow.The simultaneous monitoring of soil moisture and temperature can effectively track preferential flow and indicate the water movement.Temperature data was a more sensitive indicator of the seepage paths of preferential flow compared to moisture data.
文摘The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.
基金This research was financially supported by the National Natural Science Foundation of China(Nos.52208384 and 51934001)the National Key Research and Development Program of China(No.2021YFB3401501)the State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,Jianghan University(No.PBSKL2022C05).
文摘In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction ofthe explosion stress wave and blasting effect. Herein, we examine the explosion wave field and rock breaking effect in terms of shockwave collision, stress change of the blast hole wall in the collision zone, and crack propagation in the collision zone. The produced shockwave on the collision surface has an intensity surpassing the sum of the intensities of the two colliding explosion shock waves. At the collisionlocation, the kinetic energy is transformed into potential energy with a reduction in particle velocity at the wave front and the wavefront pressure increases. The expansion form of the superposed shock wave is dumbbell-shaped, the shock wave velocity in the collisionarea is greater than the radial shock wave velocity, and the average propagation angle of the explosion shock waves is approximately 60°.Accordingly, a fitted relationship between blast hole wall stress and explosion wave propagation angle in the superposition area is plotted.Under the experimental conditions, the superimposed explosion wave stress of the blast hole wall is approximately 1.73 times the singleexplosionwave incident stress. The results of the model test and numerical simulations reveal that large-scale radial fracture cracks weregenerated on the blast hole wall in the superimposed area, and the width of the crack increased. The width of the large-scale radial fracturecracks formed by a strong impact is approximately 5% of the blast hole length. According to the characteristics of blast hole wallcompression, the mean peak pressures of the strongly superimposed area are approximately 1.48 and 1.84 times those of the weakly superimposedand nonsuperimposed areas, respectively.
