Abstract
The stability of rock slopes to combine minimum cost reasonable safety is increasing in importance in our highway system. Factors that influence stability include rock type, strength and structure, groundwater, degree of weathering, vibration, regional stresses and slope geometry. The method of evaluating stability involves a combination of the principles of soil mechanics and an evaluation of structural rock defects. A detailed approach for investigation programs is presented. Field control following construction is often desirable. Equipment and devices presently available are described. If failures should occur, etc.