Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion inte...Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion intensity.The present study aimed to estimate soil erosion rate in the hydro-fluctuation belt of the Pubugou Reservoir,Southwest China,based on the framework of Universal Soil Loss Equation(USLE).An attempt has been made to modify the original USLE by including the reservoir water erosivity(W),a new factor into the model.Soil erosion rate from different land use types were quantitatively estimated,using the USLE and the modified USLE respectively.Field observation showed that soil erosion rate in dry farmland,bare land and grassland was 4700,44600 and 5050 t/km2,respectively.The erosion rate assessed by the modified USLE was closely related to that recorded from the field monitoring data.The findings of this study clearly highlight the importance of inclusion of the W factor to the original USLE model while assessing soil erosion in the reservoir hydro-fluctuation belt.展开更多
After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturation- dehydration circulation （WSDC）. To quantify the rate of change of rock mec...After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturation- dehydration circulation （WSDC）. To quantify the rate of change of rock mechanical properties, samples from the Longtan dam area were measured with uniaxial compression tests after different numbers （1, 5, 10, 15, and 20） of simulated WSDC cycles. Based on the curves derived from these tests, a modified Hock- Brown failure criterion was proposed, in which a new parameter was introduced to model the cumulative damage to rocks after WSDC. A case of an engineering application was analyzed, and the results showed that the modified Hock-Brown failure criterion is useful. Under similar WSDC-influenced engineering and geological conditions, rock mass strength parameters required for analysis and evaluation of rock slope stability can be estimated according to this modified Hoek-Brown failure criterion.展开更多
Setting monitoring transect in the middle and shallow water area(altitude 156-172 m) in Three Gorges reservoir hydro-fluctuation belt to research the changing characteristics of the contents of N, P,K,pH and organic m...Setting monitoring transect in the middle and shallow water area(altitude 156-172 m) in Three Gorges reservoir hydro-fluctuation belt to research the changing characteristics of the contents of N, P,K,pH and organic matter of the soil which experienced the influence of fluctuation the first time. The results showed that by the influence of water level fluctuating,contents of soil N,P,K,pH and organic matter had reduced in different soil layers in hydro-fluctuation belt.The available N decreased by 41.53%-59.87%,available P decreased by 5.26%- 36.76%,available K decreased by 3.55%-45.56%, total N decreased by 9.52%-40.00%,total P had no change generally,total K had decreased a little, content of organic material decreased by 7.62%- 37.83%%,pH value turned to neutral,changed by 1.73%-9.58%.展开更多
基金financially supported by the National Key Research and Development Program of China(Grant No.SQ2018YFD080041)the Sichuan Science and Technology Program(Grant No.2017SZ0188)。
文摘Soils in the hydro-fluctuation belts of the reservoirs are most highly influenced by the special hydro-conditions and reservoir operation,leading to unique soil erosion process and largely accelerate soil erosion intensity.The present study aimed to estimate soil erosion rate in the hydro-fluctuation belt of the Pubugou Reservoir,Southwest China,based on the framework of Universal Soil Loss Equation(USLE).An attempt has been made to modify the original USLE by including the reservoir water erosivity(W),a new factor into the model.Soil erosion rate from different land use types were quantitatively estimated,using the USLE and the modified USLE respectively.Field observation showed that soil erosion rate in dry farmland,bare land and grassland was 4700,44600 and 5050 t/km2,respectively.The erosion rate assessed by the modified USLE was closely related to that recorded from the field monitoring data.The findings of this study clearly highlight the importance of inclusion of the W factor to the original USLE model while assessing soil erosion in the reservoir hydro-fluctuation belt.
基金supported by the National Natural Science Foundation of China under No. 41630639the National Basic Research Program of China (2014CB744703)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China (No. 2016JQ4014)China Postdoctoral Science Foundation (2016M602743)
文摘After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturation- dehydration circulation （WSDC）. To quantify the rate of change of rock mechanical properties, samples from the Longtan dam area were measured with uniaxial compression tests after different numbers （1, 5, 10, 15, and 20） of simulated WSDC cycles. Based on the curves derived from these tests, a modified Hock- Brown failure criterion was proposed, in which a new parameter was introduced to model the cumulative damage to rocks after WSDC. A case of an engineering application was analyzed, and the results showed that the modified Hock-Brown failure criterion is useful. Under similar WSDC-influenced engineering and geological conditions, rock mass strength parameters required for analysis and evaluation of rock slope stability can be estimated according to this modified Hoek-Brown failure criterion.
文摘Setting monitoring transect in the middle and shallow water area(altitude 156-172 m) in Three Gorges reservoir hydro-fluctuation belt to research the changing characteristics of the contents of N, P,K,pH and organic matter of the soil which experienced the influence of fluctuation the first time. The results showed that by the influence of water level fluctuating,contents of soil N,P,K,pH and organic matter had reduced in different soil layers in hydro-fluctuation belt.The available N decreased by 41.53%-59.87%,available P decreased by 5.26%- 36.76%,available K decreased by 3.55%-45.56%, total N decreased by 9.52%-40.00%,total P had no change generally,total K had decreased a little, content of organic material decreased by 7.62%- 37.83%%,pH value turned to neutral,changed by 1.73%-9.58%.
