Abstract: Tensile cracking characteristics of gravelly core material are crucial for in-depth knowledge of hydraulic fracturing, longitudinal cracks and abutment transverse cracks of high earth core dams. However, the existing research is still not deep enough. Using the self-developed uniaxial tensile test device, a series of uniaxial tensile tests was carried out on the core materials with different gravel contents. Based on the test results, the mechanism of the cracking failure of the gravelly core material was analyzed. The following conclusions are obtained: for the samples under the maximum dry density and the optimum water content, the tensile strength and tensile strain of the gravelly core material decrease linearly with the increase of gravel content; the tensile stress-strain curves of all samples can be described in a piecewise exponential relationship, i.e. positive and negative exponential function for the test curves before and after the ultimate tensile stress, respectively. A series of consolidated-drained triaxial tests was also conducted, the relationship between the tensile strength and the strength index of each sample was analyzed. The tensile strength has a good linear relationship with its cohesion. This relationship can be used to estimate the tensile strength of the gravelly core material without test conditions. The relevant test results can provide reference for the anti-crack design of the actual earth core rockfill dam.

Key words: gravelly core material, gravel content, stress-strain relationship, tensile strength, cohesion