铁尾砂抗剪强度参数随固结度变化规律研究

Variation of Shear Strength Parameters of Iron Tailings with the Degree of Consolidation

摘要:

为了探究铁矿尾矿砂抗剪强度参数随固结度的变化规律，分别对不同固结度、不同干密度的铁矿尾矿砂进行三轴固结不排水试验（CU试验），以总应力法和有效应力法得到尾矿砂的抗剪强度参数及有效抗剪强度参数。分析表明，对于同一干密度的尾矿砂，随着固结度的增加，抗剪强度指标及有效抗剪强度指标均逐渐增加。固结度的变化对黏聚力c及有效黏聚力c'影响较小，对内摩擦角φ以及有效内摩擦角φ'影响较大。φ及φ'随着干密度的增加成线性增长趋势，且不同固结度下的γ_d-φ曲线、γ_d-φ'曲线拟合度较高。因此，在尾矿坝稳定性评价及安全管理中，考虑尾矿砂的抗剪强度随固结度的不同而变化，可使尾矿坝稳定性分析更符合实际情况。

Abstract:

To investigate the change law of shear strength parameters of iron ore tailings with the consolidation degree, this paper conducted a series of triaxial consolidation undrained (CU) tests on iron ore tailings with different consolidation degrees and different dry densities. The shear strength parameters and effective shear strength parameters of the tailings sand were obtained by the total stress method and the effective stress method, respectively. The analysis results showed that for tailings sand with the same dry density, as the consolidation degree increases, both the shear strength index and the effective shear strength index increase gradually. The change in the degree of consolidation has a small effect on the cohesion c and the effective cohesion c', and has a large effect on the internal friction angle φ and the effective internal friction angle φ'. φ and φ' have a linear growth trend with the increase of dry density, and the γ_d-φ curve and γ_d-φ' curve have a high fitting degree under different consolidation degrees. Therefore, in the stability evaluation and safety management of tailings dams, if we consider the shear strength variation of the tailings sand with the degree of consolidation, the stability analysis of tailings dams will be more in line with the actual situation.