THE EFFECT OF STRAIN RATE AND BACK PRESSURE ON STRENGTH AND DEFORMATION PROPERTIES OF IMPROVED SANDS BY CHEMICAL GROUT

Abstract

 In this research, the triaxial compression tests are carried out to grasp the strength and deformation properties of improved sand by chemical grout. In this paper, examinations were performed to confirm the effect of strain rate and back pressure on the deformation properties as a first step. From the results, an upper yield point of triaxial compression tests were shown in around the unconfined compression strength and failure strain of them, and the deviator stress became to the maximum according to the strain hardening behavior thereafter. Although upper yield stress increased as increasing the strain rate, the maximum deviator stress decreased as increasing the strain rate irrespective drainage condition. In addition, upper yield stress decreased as increasing the back pressure, but the maximum deviator stress increased as increasing the negative pressure provided with increasing the back pressure in undrained conditions.