EVALUATION OF ROCKFALL AND ITS CONTROL

Abstract

LITTLE VALUE, IN TERMS OF SAFETY, IS BEING RECEIVED FROM ENORMOUS EXPENDITURES TO PRODUCE ROCKFALL AREAS. BECAUSE OF THIS, AN EXTENSIVE STUDY WAS MADE THROUGHOUT WASHINGTON STATE TO DETERMINE THE MECHANICS OF ROCKFALL FROM CLIFFS AND TALUS SLOPES AND VARIOUS DITCH SECTIONS AND ROCK FENCES FOUND MOST EFFECTIVE IN CONTAINING IT. RESULTS OF THIS INVESTIGATION WERE A NEW APPROACH TO THE THEORY OF ROCK CUTS AND A TESTED METHOD FOR CONTAINING ROCKFALL. AMONG THOSE ASPECTS OF ROCKFALL STUDIED WERE /1/ THE PROBLEM OF ROCKFALL ALONG MOUNTAINOUS HIGHWAYS, /2/ THE PROBLEM OF COMPARATIVE SAFETY, /3/ A COLLECTION OF DATA USING A 16-MM MOTION PICTURE CAMERA RECORDING THE HABITS OF ROCK FALL OVER A GREAT NUMBER OF SLOPE ANGLES, HEIGHTS, ETC., AS WELL AS THE EFFECT THAT SIZE, SHAPE, AND TYPE OF ROCK MIGHT HAVE ON REBOUND AND TRAJECTORY, /4/ A MATHEMATICAL TREATMENT OF ROCK TRAJECTORY, /5/ A DESIGN TO COPE WITH THE PROBLEM BASED ON OBSERVED DATA, /6/ EVALUATION OF THIS DESIGN IN ACTUAL FIELD TESTS AND /7/ ARGUMENTS FOR CHANGING PRESENT STANDARDS REGARDING FALLOUT AREAS. DESIGN CRITERIA DESCRIBING A MORE REALISTIC RELATIONSHIP AMONG THE VARIABLES OF CLIFFS, ANGLE OF SLOPES, DEPTH OF DITCHES AND WIDTH OF ROCKFALL AREAS WERE PRESENTED.