饱和度对离子型稀土矿抗剪强度的影响

Effect of saturation degree on shear strength of ion-adsorption rare-earth ore

为获得离子型稀土矿体在非饱和-饱和状态下的强度特性,以江西龙南地区某离子型稀土矿为研究对象,利用GDS非饱和三轴仪对不同饱和度的重塑矿体开展常规三轴试验,研究发现:饱和度对矿体的应力-应变关系有显著影响,随着饱和度的增加,矿体的应力-应变关系由应变软化型逐渐转变为应变硬化型,破坏模式由脆性破坏转变为塑性破坏,抗剪强度呈非线性降低;饱和度的变化对矿体的内摩擦角影响不明显,对总黏聚力的影响很大,可认为饱和度变化对矿体强度的影响,主要是通过改变总黏聚力的大小来起作用的;通过线性回归分析,矿体总黏聚力与含水量呈半对数线性关系,总黏聚力与饱和度呈乘幂函数关系,并针对该离子型稀土矿提出与饱和度有关的总应力抗剪强度公式。

In order to obtain strength characteristics of ion-adsorption rare-earth ore in the unsaturatedsaturated state,conventional triaxial testing were carried on remoulded ion-adsorption rare-earth ore with different saturations using GDS unsaturated triaxial apparatus,based on a ion-adsorption rare-earth ore in Long Nan of Jiang xi,The results of the study show that saturations have a significant impact on the stressstrain relation,as the saturations increase,the stress-strain relation changes from strain softening type into strain hardening type,failure mode changes from brittle fracture into plastic failure,and shear strength reduces nonlinearly with increase of saturations.Change of saturations has no obvious effect on the internal friction angle of ore samples,but it has a obvious effect on cohesion,which can attribute to the effects of saturations change the strength of ore body.By linear regression analysis,the conclusion is indicated that the total cohesion has semilog linear relationship with water content and total cohesion has power function relationship with saturations,and the total stress shear strength formula related to saturations for the ionadsorption rare-earth ore are proposed.