INFLUENCE OF SAMPLE PREPARATION TECHNOLOGY ON SHEAR BEHAVIOR OF INHERENT ANISOTROPIC SAND IN TRIAXIAL TESTS ¹⁾

Based on the capillary effect and using the freeze thawing method for the sand grain, a sample preparation is suggested to make the sand sample with an arbitrarily sedimentary direction in the range of 0°~90° for any grain composition. A series of triaxial compression shearing tests are performed under a medium confining pressure, the results show that the preparation method combined with the moist sampling and the freeze thawing has a significant influence on the shearing behavior of the sand. With the method, the developing speed of the relation between stress and strain will be decreased, and the ultimate shearing strength will be lowered, but with little influence on the residual shearing strength. Under other stress path conditions of the triaxial test, such as the triaxial tension, the reduced triaxial compression and the triaxial isostress compression, the sample preparation has little influence on the results. The suggested sample preparation method is applicable for the experimental study of the sand inherent anisotropy behavior.