DETERMINATION OF MOTION AND DEFLECTION OF RETAINING WALLS (INCLUDES SUMMARY, PUBLISHED UNDER SEPARATE COVER)

THE PURPOSE WAS TO ESTABLISH A PHOTOGRAMMETRIC METHOD TO DETERMINE THE MOTION AND DEFLECTION OF RETAINING WALLS. THE STUDY IS DIVIDED INTO TWO PARTS; THE FIRST ONE IS THE THEORY OF PHOTOGRAMMETRIC DEFORMATION. THE THEORETICAL CONCEPT OF PHOTOGRAMMETRIC MODEL DEFORMATION IS GIVEN FOR ANALOGICAL, SEMI- ANALYTICAL, AND ANLYTICAL PHOTOGRAMMETRY. TO MEET THE PROBLEM OF SYSTEMATIC DISTORTION OF THE PHOTOGRAMMETRIC MODEL DUE TO MEASUREMENT ERROR, AN APPROXIMATE CORRECTION METHOD WAS DEVELOPED. THE SECOND PART OF THE STUDY CONSISTED OF PRACTICAL EXPERIMENTATION AND TECHNICAL DEVELOPMENT. THE EXPERIMENT WAS PERFORMED ON A 300-FOOT SIMULATED RETAINING WALL, CONSISTING OF A MATRIX OF TARGETS. MOVABLE TARGETS IMITATED ANY FORM OF DEFLECTION. IT WAS FOUND THAT THE MINIMUM DETECTABLE DEFLECTION OF A RETAINING WALL IS THREE TIMES THAT OF THE RESIDUAL STANDARD ERROR OF THE PHOTOGRAMMETRIC SYSTEM, OR ABOUT 0.15". THE CORRECTION METHOD PROVED TO BE HIGHLY EFFECTIVE. THE OPTIMUM GEOMETRY DEFINED BY THE THEORETICAL PART AS BEING A SYMMETRICALLY CONVERGENT PHOTOGRAPH RECEIVED PRACTICAL CONFIRMATION. IT WAS CONCLUDED THAT THE DETECTION AND MONITORING OF THE DEFLECTION OF RETAINING WALLS IS POSSIBLE AND ECONOMICALLY FEASIBLE. ANALYTIC PHOTOGRAMMETRY PROVIDES THE BEST RESULTS. NO SPECIAL INSTRUMENTATION IS REQUIRED TO PERFORM THIS MEASUREMENT BUT IT IS RECOMMENDED THAT A CONVENTIONAL AERIAL CAMERA SHOULD BE USED AS A "FIRST ORDER" STEREO-PLOTTER. CONTINUOUS MONITORING OF POTENTIAL SLIDE AREAS COULD LEAD TO THE PRECISE DETERMINATION OF STABILITY SLOPES FOR CERTAIN TERRAIN, SOIL, AND METEOROLOGICAL CONDITIONS OR PREDICTIONS, AND THEREBY TO THE PREVENTION OF SLIDES.