EMBANKMENT ANALYSIS AND FIELD CORRELATION

EXPERIMENTAL RESULTS FROM A PROGRAM TO DEVELOP ACCURATE AND RELIABLE INSTRUMENTATIONS FOR STRESS AND DEFORMATION MEASUREMENTS IN HIGHER EMBANKMENTS ARE NUMERICALLY ANALYZED FOR A PARTICULAR EMBANKMENT TO COMPARE THE RESULTS WITH THE FIELD MEASUREMENTS. THIS COMPARISON PERMITS AN ASSESSMENT OF THE ACCURACY OF THE MATHEMATICAL MODEL AND PREDICTION TECHNIQUE. THE ANALYSIS IS BASED ON A PLANE STRAIN SYSTEM WITH LINEARLY ELASTIC ISOTROPIC MATERIALS THAT IS CONSTRUCTED AND LOADED INCREMENTALLY. THE FINITE ELEMENT METHOD IS EMPLOYED TO OBTAIN STRESSES AND DISPLACEMENTS IN THIS TYPICAL CROSS-SECTION. THE CONTINUOUS SYSTEM IS IDEALIZED AS AN ASSEMBLAGE OF SMALLER, BUT FINITE, ELEMENTS CONNECTED AT A DISCREET NUMBER OF POINTS CALLED NODES. THE BASIS FOR THE METHOD IS A CONSISTENTLY DERIVED STIFFNESS FOR EACH OF THESE ELEMENTS, THE STIFFNESS BEING A RELATIONSHIP BETWEEN THE GENERALIZED FORCES AND THE DISPLACEMENTS AT THE NODES OF EACH ELEMENT. STIFFNESS OF THE ELEMENTS USED IS PREDICTED ON A MATERIAL POSSESSING LINEAR ELASTIC PROPERTIES. EXAMINATION OF THE ANALYTICAL RESULTS AND COMPARISON WITH THE FIELD DATA INDICATE THAT THE MATHEMATICAL MODEL CAN LEAD TO QUALITATIVE PREDICTIONS. THE WEAKEST FEATURE OF THE MATHEMATICAL MODEL IS THE MATERIAL CHARACTERIZATION. IT IS RECOMMENDED THAT: (1) ESTIMATES FOR STRESS AND DISPLACEMENT FIELDS SHOULD BE OBTAINED PRIOR TO PLACEMENT OF INSTRUMENTATION, (2) LATERAL PRESSURES SHOULD BE MEASURED AS WELL AS VERTICAL STRESSES, (3) VERTICAL PRESSURE CELLS MIGHT BE USED TO CALIBRATE THE CELLS MEASURING HORIZONTAL STRESSES, AND (4) AN ACCURATE DETERMINATION OF THE MATERIAL PROPERTIES OF THE EARTH FILL MUST BE MADE WHEN INSTRUMENTING AN EMBANKMENT.