Abstract:A tailings dam is constructed by gravel with one-step constructed method in two phases. Before the second phase of the project, the physical and mechanical properties of the dam gravel were systematically tested, which provided a theoretical basis for the stability evaluation and analysis of the dam heightening project. On-site sampling and particle analysis showed that the dam material was well-graded gravel. At the same time, based on the dry density index detected on site, large-scale triaxial shear tests of this gravel under different consolidation and drainage conditions were carried out indoors. The test results show that the cohesion c is 20kPa and the friction angle φ is 31.8° for CD test， the cohesion c is 8kPa and the friction angle φ is 29.2° for CU test, the cohesion c is 107kPa and the friction angle φ is 4.0° for UU test.
