Abstract:In order to develop a method of determining the optimal angle of planting holes on high steep slopes, four indicators of space utilization, degree of structural surface exposure, water recharge capacity, and anti-evaporation capacity were proposed to determine the optimal angle of planting holes for slope regreening, COMSOL Multiphysics was used to simulate the unsaturated infiltration of porous media and water vapor transport by heat and moisture coupling, and the influence of the change of the angle of planting holes on these four indicators was discussed. In order to verify the simulation results, an experimental site was established at the slope in Yanxiu Garden of Xuzhou Garden Expo Park, and the data of the test holes were monitored, measured and processed for analysis on site. The results show that under the condition of controlling depth of 50cm and diameter of 20cm, the planting hole angle of 40°~60° can ensure high space utilization; in the range of 30°~80°, the larger the angle of planting hole is, the better it is for receiving water recharge by natural rainfall or spraying maintenance, but at the same time, the resistance to evaporation under high temperature and dry conditions is weakened; the angle of the planting hole corresponding to best exposure of the structural surface can be obtained by establishing and calculating the 3D model of the slope and the structural surface. The research results and the optimal angle determination method have good guidance for regreening project.
