Prediction of Erosion on Cut or Fill Slopes. Final Report

摘要

Previous research relative to the Universal Soil Loss Equation (USLE) and rainfall simulators are reviewed. A programmable rainfall simulator was modified and successfully operated on highway slopes with slope steepness from 9% to 50% at Putnamville and Evansville, Indiana in 1985 and 1986. Special techniques were introduced for preparation of the test plots and operation of the simulator. Distribution of the simulated rainfall intensity and its effects on soil erosion were studied under conditions of different nozzle heights, different slope steepnesses and different nozzle tilting angles. The slope steepness factor was extended from 18% to 50%. The soil erodibility factor was measured and compared with that proposed by previous researchers. A rotational shear device was modified and operated to obtain critical shear stresses of soil samples to rate the soil erodibility factor. Examples are given for predicting soil erosion on highway slopes at five locations in or around the state of Indiana, using the USLE.