Almost all intraplate caprocks experienced strong deformation during the convergence of microplates, and then disintegrated into many secondary geologic units with the special characters, such as irregular boundaries ...Almost all intraplate caprocks experienced strong deformation during the convergence of microplates, and then disintegrated into many secondary geologic units with the special characters, such as irregular boundaries and particular structural assemblages. In order to understand the formation mechanism of these special phenomena, a rheological experiment on the structural scenery of the Tongling area is carried out. The result shows that the primary regular and uniform boundaries of the Tongling area becomes irregular because of the enclosing and confinement of surrounding geological units in the process of 'compression-shearing-rotation-drag'; simultaneously, two specific 'drag depressions' developed at two opposite corners of the block. The former and the later phenomena can be regarded as a typical regional-scale rheological effect and necessary outcome of intraplate deformation respectively.展开更多
Zokors are common subterranean rodents that inhabit agricultural fields, shrublands, and grasslands in the arid and semi-arid regions of China. Zokor burrowing activities can alter soil structure and affect soil hydro...Zokors are common subterranean rodents that inhabit agricultural fields, shrublands, and grasslands in the arid and semi-arid regions of China. Zokor burrowing activities can alter soil structure and affect soil hydrological processes;however, there are few studies regarding their effects on soil preferential flow in the Mu Us sandy land. An evaluation of the effects of zokor disturbance on their habitat and soil water is important for understanding the ecological role of zokors in the soil ecosystem of the Mu Us sandy land. A field dye-tracing experiment was conducted in the Gechougou watershed on the southeastern edge of the Mu Us sandy land to investigate the effect of zokor burrowing activity on soil preferential flow characteristics. Our results showed that the density of zokor tunnels was the highest(0.40–0.46 m m^(-2)) under 30%–50% vegetation coverage and that the tunnels were approximately 3 cm from the surface.Both stained area ratio and stained path number were higher at sites with zokors than without zokors. Stained path widths were 10–80 and > 80 mm at zokor-harboring sites exhibiting homogeneous flow and heterogeneous finger flow, respectively. In the absence of zokors, homogeneous flow and highly interacted macropore flow were predominant. Soil water content below the zokor tunnels was higher than that above the tunnels. Moderate disturbance of soil structure by zokor activity facilitated soil water infiltration. These results enabled a better understanding of the effect of soil fauna on soil structure and hydrological processes and provided recommendations for ecological construction and renovation in arid and semi-arid regions.展开更多
At present, the method of calculating the turbulent flow width around the bridge pier is not given in the ＂Standard for Inland River Navigation＂ （GB50139-2004） in China, and the bridge designer usually increases t...At present, the method of calculating the turbulent flow width around the bridge pier is not given in the ＂Standard for Inland River Navigation＂ （GB50139-2004） in China, and the bridge designer usually increases the bridge span in order to ensure the navigation safety, which increases both of the structural design difficulty and the project investments. Therefore, it is extremely essential to give a research on the turbulent flow width around the bridge pier. Through the experiments of the fixed bed and the mobile bed, the factors influencing the turbulent flow width around the bridge pier have been analyzed, such as the approaching flow speed, the water depth, the angles between the bridge pier and the flow direction, the sizes of bridge pier, the shapes of the bridge pier, and the scouting around the bridge pier, etc. Through applying the dimension analytic method to the measured data, the formula of calculating the turbulent flow width around the bridge pier is then inferred.展开更多
文摘Almost all intraplate caprocks experienced strong deformation during the convergence of microplates, and then disintegrated into many secondary geologic units with the special characters, such as irregular boundaries and particular structural assemblages. In order to understand the formation mechanism of these special phenomena, a rheological experiment on the structural scenery of the Tongling area is carried out. The result shows that the primary regular and uniform boundaries of the Tongling area becomes irregular because of the enclosing and confinement of surrounding geological units in the process of 'compression-shearing-rotation-drag'; simultaneously, two specific 'drag depressions' developed at two opposite corners of the block. The former and the later phenomena can be regarded as a typical regional-scale rheological effect and necessary outcome of intraplate deformation respectively.
基金supported by the National Natural Science Foundation of China(Nos.41807011 and 41907012)the Chinese Universities Scientific Fund(No.2452022335)the Open Fund for Key Lab.of Ecological Study of Ningxia University,China(No.LDER2022Z01)。
文摘Zokors are common subterranean rodents that inhabit agricultural fields, shrublands, and grasslands in the arid and semi-arid regions of China. Zokor burrowing activities can alter soil structure and affect soil hydrological processes;however, there are few studies regarding their effects on soil preferential flow in the Mu Us sandy land. An evaluation of the effects of zokor disturbance on their habitat and soil water is important for understanding the ecological role of zokors in the soil ecosystem of the Mu Us sandy land. A field dye-tracing experiment was conducted in the Gechougou watershed on the southeastern edge of the Mu Us sandy land to investigate the effect of zokor burrowing activity on soil preferential flow characteristics. Our results showed that the density of zokor tunnels was the highest(0.40–0.46 m m^(-2)) under 30%–50% vegetation coverage and that the tunnels were approximately 3 cm from the surface.Both stained area ratio and stained path number were higher at sites with zokors than without zokors. Stained path widths were 10–80 and > 80 mm at zokor-harboring sites exhibiting homogeneous flow and heterogeneous finger flow, respectively. In the absence of zokors, homogeneous flow and highly interacted macropore flow were predominant. Soil water content below the zokor tunnels was higher than that above the tunnels. Moderate disturbance of soil structure by zokor activity facilitated soil water infiltration. These results enabled a better understanding of the effect of soil fauna on soil structure and hydrological processes and provided recommendations for ecological construction and renovation in arid and semi-arid regions.
基金Supported by the West Waterway Transportation Construction Foundation under Grant No.2004-328-000-40.
文摘At present, the method of calculating the turbulent flow width around the bridge pier is not given in the ＂Standard for Inland River Navigation＂ （GB50139-2004） in China, and the bridge designer usually increases the bridge span in order to ensure the navigation safety, which increases both of the structural design difficulty and the project investments. Therefore, it is extremely essential to give a research on the turbulent flow width around the bridge pier. Through the experiments of the fixed bed and the mobile bed, the factors influencing the turbulent flow width around the bridge pier have been analyzed, such as the approaching flow speed, the water depth, the angles between the bridge pier and the flow direction, the sizes of bridge pier, the shapes of the bridge pier, and the scouting around the bridge pier, etc. Through applying the dimension analytic method to the measured data, the formula of calculating the turbulent flow width around the bridge pier is then inferred.
