Nonlinearity Shear Mode Fracture Toughness Investigation of the Original State Frozen Soil

In order to obtain shear-mode fracture toughness of the original(nondistributed) frozen soil which constitutive relation, water contained and temperature distribution are not distributed, a four-point banding experimental model to measure the nonlinearity fracture toughness under shear-mode loading in frozen soil was presented. The certain experimental methodology including specimen´s preparation of the original state frozen soil, the precrack of frozen soil specimen, the measurement of critical crack length using dye penetrant technique, non-linearity correction factor determination and relationships between non disturbed frozen soil and disturbed frozen soil, etc. has been studied in the paper. There exist obvious differences of fracture toughness between undisturbed and disturbed soils although the samples are tested under the same conditions of initial water content, dry density and temperature. Both the experiment method of testing the nonlinear fracture toughness of the shear mode(type II) and the experimental data of the nonlinear fracture toughness for the original state frozen soil in this paper can offer the basis for the frozen soil nonlinear fracture theory research and engineering application.