A METHOD FOR DETERMINING THE DEGREE OF SOIL EROSION RISK BASED UPON SOIL GRADING CHARACTERISTICS

摘要

A METHOD OF DETERMINING THE DEGREE OF SOIL EROSION RISK BASED UPON SOIL GRADING CHARACTERISTICS. WHEN SAID METHOD IS APPLIED TO HILL SLOPE, RESULTANT ERODIBILITY INDEX CAN BE TREATED AS EROSION INDEX TO INDICATE THE DEGREE OF LANDSLIDE. PARTICLE SIZE DISTRIBUTION FOR SOIL UNDER TEST IS OBTAINED FROM SIEVING ANALYSIS AND HYDROMETER TESTS. RESULTING DISTRIBUTION OF PARTICLE IS APPROPRIATELY CLASSIFIED AS PERCENTAGE OF SAND, SILT AND CLAY ACCORDING TO PREDETERMINED DEFINITIONS. THE SOIL EROSION INDEX IS CALCULATED FROM THESE DETERMINED PERCENTAGES OF SAND, SILT AND CLAY. THE STEPS OF CLASSIFYING PARTICLE OF VARIOUS SIZES UP TO THE YIELDING OF A SOIL EROSION INDEX, MAY BE CARRIED OUT BY MEANS OF TABLES, NOMOGRAPH OR PROGRAMMING IN FORMS OF MECHANICAL, ELECTRICAL, ELECTRONIC OR COMPUTER SOFTWARE. A PREFERRED TABLE FOR CALCULATING SOIL EROSION INDEX BASED ON THE SUM VALUES OF PERCENTAGE OF SAND PLUS PERCENTAGE OF SILT AND VALUES OF PERCENTAGE OF CLAY IS EXEMPLIFIED. FIGURE 1