MODULUS OF SOIL REACTION AS DETERMINED FROM THE TRIAXIAL SHEAR TEST

IN 1942 SPANGLER PUBLISHED HIS CLASSICAL THEORY FOR THE DEFLECTION OF UNDERGROUND CONDUITS. THIS THEORY HAS RECEIVED ONLY LIMITED USE, PARTIALLY BECAUSE OF THE INABILITY TO DETERMINE THE PROPER NUMERICAL VALUE OF THE MODULUS OF SOIL REACTION. SEVERAL DIFFERENT ATTEMPTS HAVE BEEN MADE TO DETERMINE THIS MODULUS IN THE LABORATORY BUT EACH HAS MET WITH ONLY LIMITED SUCCESS. BURNS AND RICHARDS (1964) SOLVED THE PROBLEM OF THE BURIED CONDUIT USING THE THEORY OF ELASTICITY BY ASSUMING IDEAL ELASTIC CONDITIONS. THEIR EQUATIONS HAVE BEEN USED TO CALCULATE THE MODULUS OF SOIL REACTION. THE ENSUING EQUATION BECAME VERY DIFFICULT TO EVALUATE; THEREFORE, THE COMPUTER WAS USED TO DETERMINE AN APPROXIMATE RELATIONSHIP FOR THE NECESSARY VARIABLES AND THE MODULUS OF SOIL REACTION. THE MODULUS HAS ALSO BEEN SHOWN TO BE DETERMINABLE FROM THE TRIAXIAL SHEAR TEST. THE MODULUS IS DEPENDENT ON POISSONS RATIO AND THE MODULUS OF ELASTICITY. BOTH VALUES CAN BE DETERMINED FROM A SINGLE TRIAXIAL SHEAR TEST. DATA OBTAINED FROM A TRIAXIAL SHEAR TEST ARE USED TO CALCULATE THE MODULUS OF SOIL REACTION WHICH IS THEN COMPARED WITH THE VALUE MEASURED IN THE DEVICE CONSTRUCTED BY WATKINS AND NEILSON CALLED THE MODPARES DEVICE. /AUTHOR/