In Japan, floods occur frequently in urban areas because non-infiltrating areas are seeing increased urbanization. To prevent floods, urban basins must improve the infiltration capacity and water retention of the whol...In Japan, floods occur frequently in urban areas because non-infiltrating areas are seeing increased urbanization. To prevent floods, urban basins must improve the infiltration capacity and water retention of the whole basin. There are several basic technologies for river basin management, such as infiltration trenches or rainwater storage. However, a method of soil amendment that prevents flood disasters has not been established. This study aims to evaluate the infiltration capacity of soil amendments using bamboo charcoal and humus. A constant-head infiltration test and rainfall simulation were conducted to evaluate the properties of the soil amendments. The constant-head infiltration test＇s results showed that soils mixed with 30% humus had the greatest potential for influencing initial and final infiltration rates, and the more the mixing rates of bamboo charcoal and humus were increased, the higher the water retention capacity. The results of the rainfall simulation showed that soils mixed with 30% humus had the highest final infiltration rates and lowest multiplication spillage. To reduce the runoff volume using soil amendment technology, it is important to delay overland flow, and the hydraulic properties of the soils mixed with bamboo charcoal and humus were as effective as those of granite soils.展开更多
A methodology for identifying and calibrating the material parameters for a coupled hydro-mechanical problem is presented in this pape r.For validation purpose,a laboratory-based water infiltration test was numericall...A methodology for identifying and calibrating the material parameters for a coupled hydro-mechanical problem is presented in this pape r.For validation purpose,a laboratory-based water infiltration test was numerically simulated using finite element method(FEM).The test was conducted using a self-designed column-type experimental device,which mimicked the wetting process of a candidate backfill material in a nuclear waste repository.The real-time measurements of key state variables(e.g.water content,relative humidity,temperature,and total stresses)were performed with the monitoring sensors along the height of cylindrical soil sample.For numerical simulation,the modified Barcelona Basic Model(BBM)along with soil-water retention model for compacted bentonite was used.It shows that the identified model parameters successfully captured the moisture migration process under an applied hydraulic gradient in a bentonite-based compacted soil sample.A comparison between the measured and predicted values of total stresses both in axial and lateral directions along with other state variables revealed that heterogeneous moisture content was distributed along the hydration-path,resulting in non-uniform stress-deformation characteristics of soil.展开更多
The air infiltration rate of buildings strongly influences indoor environment and energy consumption.In this study,several traditional methods for determining the air infiltration rate were compared,and their accuracy...The air infiltration rate of buildings strongly influences indoor environment and energy consumption.In this study,several traditional methods for determining the air infiltration rate were compared,and their accuracy in different scenarios was examined.Additionally,a method combining computational flow dynamics(CFD)with the Swami and Chandra(S-C)model was developed to predict the influence of the surrounding environment on the air infiltration rate.Two buildings in Dalian,China,were selected:one with a simple surrounding environment and the other with a complex surrounding environment;their air infiltration rates were measured.The test results were used to validate the accuracy of the air infiltration rate solution models in different urban environments.For the building with a simple environment,the difference between the simulation and experimental results was 0.86%–22.52%.For the building with a complex environment,this difference ranged from 17.42%to 159.28%.We found that most traditional models provide accurate results for buildings with simple surrounding and that the simulation results widely vary for buildings with complex surrounding.The results of the method of combining CFD with the S-C model were more accurate,and the relative error between the simulation and test results was 10.61%.The results indicate that the environment around the building should be fully considered when calculating the air infiltration rate.The results of this study can guide the application of methods of determining air infiltration rate.展开更多
文摘In Japan, floods occur frequently in urban areas because non-infiltrating areas are seeing increased urbanization. To prevent floods, urban basins must improve the infiltration capacity and water retention of the whole basin. There are several basic technologies for river basin management, such as infiltration trenches or rainwater storage. However, a method of soil amendment that prevents flood disasters has not been established. This study aims to evaluate the infiltration capacity of soil amendments using bamboo charcoal and humus. A constant-head infiltration test and rainfall simulation were conducted to evaluate the properties of the soil amendments. The constant-head infiltration test＇s results showed that soils mixed with 30% humus had the greatest potential for influencing initial and final infiltration rates, and the more the mixing rates of bamboo charcoal and humus were increased, the higher the water retention capacity. The results of the rainfall simulation showed that soils mixed with 30% humus had the highest final infiltration rates and lowest multiplication spillage. To reduce the runoff volume using soil amendment technology, it is important to delay overland flow, and the hydraulic properties of the soils mixed with bamboo charcoal and humus were as effective as those of granite soils.
基金the German Research Foundation(DFG)for the financial support(Grant No.SCHA 675/17-1)。
文摘A methodology for identifying and calibrating the material parameters for a coupled hydro-mechanical problem is presented in this pape r.For validation purpose,a laboratory-based water infiltration test was numerically simulated using finite element method(FEM).The test was conducted using a self-designed column-type experimental device,which mimicked the wetting process of a candidate backfill material in a nuclear waste repository.The real-time measurements of key state variables(e.g.water content,relative humidity,temperature,and total stresses)were performed with the monitoring sensors along the height of cylindrical soil sample.For numerical simulation,the modified Barcelona Basic Model(BBM)along with soil-water retention model for compacted bentonite was used.It shows that the identified model parameters successfully captured the moisture migration process under an applied hydraulic gradient in a bentonite-based compacted soil sample.A comparison between the measured and predicted values of total stresses both in axial and lateral directions along with other state variables revealed that heterogeneous moisture content was distributed along the hydration-path,resulting in non-uniform stress-deformation characteristics of soil.
基金the National Natural Science Foundation of China(51838007)the Tsinghua-Toyota Joint Research Institute Inter-disciplinary Program.
文摘The air infiltration rate of buildings strongly influences indoor environment and energy consumption.In this study,several traditional methods for determining the air infiltration rate were compared,and their accuracy in different scenarios was examined.Additionally,a method combining computational flow dynamics(CFD)with the Swami and Chandra(S-C)model was developed to predict the influence of the surrounding environment on the air infiltration rate.Two buildings in Dalian,China,were selected:one with a simple surrounding environment and the other with a complex surrounding environment;their air infiltration rates were measured.The test results were used to validate the accuracy of the air infiltration rate solution models in different urban environments.For the building with a simple environment,the difference between the simulation and experimental results was 0.86%–22.52%.For the building with a complex environment,this difference ranged from 17.42%to 159.28%.We found that most traditional models provide accurate results for buildings with simple surrounding and that the simulation results widely vary for buildings with complex surrounding.The results of the method of combining CFD with the S-C model were more accurate,and the relative error between the simulation and test results was 10.61%.The results indicate that the environment around the building should be fully considered when calculating the air infiltration rate.The results of this study can guide the application of methods of determining air infiltration rate.
