含水率影响下尾矿砂内摩擦角随标贯击数变化研究

尾矿砂样品在运输和存放过程中均存在易扰动的特点，但考虑到工程造价以及人力资源等因素，目前在大部分上游式尾矿坝的工程地质勘察中难以建立现场试验室，所得抗剪强度指标与实际情况存在一定误差。针对这种现状，结合某铅锌矿尾矿坝现场试验结果，从现场简易试验获得的含水率和标准贯入击数进行分析，并对基于含水率影响下尾矿砂内摩擦角随标准贯入击数变化规律进行了研究，提出了考虑上覆压力作用下标准贯入击数的修正公式，并推出了用标准贯入击数估算尾矿砂内摩擦角的方法。通过几个实例验证：除当修正后的标准贯入击数N1>8（5%< <20%）情况下以外，该方法均能够有效地估算尾矿砂内摩擦角。研究结果表明，该方法在以后的上游式尾矿堆积坝的工程地质勘察工作中具有较强的应用价值。

Variation of internal friction angle of tailings with standard penetration number under influence of water content

The tailings sample has characteristics of easily to be disturbed in the process of both transportation and storage. However, limited by human resources as well as project budget, or else factors, it is impossible to establish field laboratory for all upstream tailings dam during their engineering geological exploration, thereby leading to errors between the shear strength index and practical situation. For this reason, an extensive field testing is carried out in a lead-zinc mine tailings dam, the water content and standard penetration number can be easily obtained from field testing; and the internal friction angles of tailings as it changes through standard penetration number under the influence of the water content are studied. Considering the effect of overburden pressure, a amended expressions of standard penetration number is proposed. And using the standard penetration number，a estimation method about the internal friction angle of tailings is deduced; Finally, several examples are given to verify that except for the situation when the amended standard penetration number is N1 >8（5%< <20%），this method can estimate the internal friction angle of tailings sand effectively. The results show that, the method has a high application value in upstream tailings dams’ engineering geological exploration in the future.