砾石料尾矿坝力学性质大型三轴剪切试验研究

Study on mechanical properties of gravel tailings dam by large-scale triaxial shear test

某尾矿坝采用砾石料一次建坝方式建设,分两期实施。在开展二期工程前,对已填筑坝体砾石料的物理力学性能指标进行了系统测试,为坝体加高工程稳定性评价分析提供理论依据。现场取样进行颗粒分析表明,该筑坝料为级配良好砾,同时基于现场检测干密度指标,在室内开展了不同固结排水状态下砾石料的大型三轴剪切试验,以了解其在不同状态下的力学性能。试验结果表明:筑坝砾石料CD试验抗剪强度指标内聚力c为20 k Pa,摩擦角φ为31.8°;CU试验抗剪强度指标内聚力c为8 k Pa,摩擦角φ为29.2°;UU试验抗剪强度指标内聚力c为107 k Pa,摩擦角φ为4.0°。

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 20 k Pa and the friction angle φ is 31. 8° for CD test,the cohesion c is 8 k Pa and the friction angle φ is 29. 2° for CU test,the cohesion c is 107 k Pa and the friction angle φ is 4. 0° for UU test.