三向格栅与细粒尾矿界面特性拉拔试验研究

Pull-out test study on interface characteristics of traixial geogrid and fine tailings

为提高细粒尾矿坝的安全稳定性,提出三向格栅加筋增强细粒尾矿力学性质的方法,以细粒尾矿为填料,开展不同工况下的双向、三向格栅拉拔试验,分析2种格栅的加筋效果差异,着重研究相对密实度、含水率及法向应力对三向格栅-细粒尾矿界面特性的影响。研究结果表明:三向格栅加筋效果优于双向格栅,界面强度参数上表现为似摩擦角的差异,且法向应力越高越有利于提高三向格栅加筋效果;相对密实度的增大对界面摩擦强度提高明显,界面似黏聚力和综合摩擦因数比随相对密实度单调递增,而似摩擦角增幅很小;天然含水率下界面摩擦强度大于饱和含水率界面,前者界面似黏聚力是后者的1.28倍,而似摩擦角近似相等。

In order to improve safety and stability of fine tailings dam,a method of strengthening its mechanical properties by traixial geogrid reinforcement was put forward,and pull-out tests of biaxial and traixial geogrid under different conditions were carried out with fine tailings as fillers.Then,difference in reinforcement effects of these two geogrids were analyzed,and influence of relative density,water content and normal stress on interface characteristics of traixial geogrid were emphatically studied.The results show that traixial geogrid has better reinforcement effect than biaxial one,and interface strength parameters show difference of pseudo-friction angle.Moreover,the higher normal stress is,the better reinforcement effect of traixial geogrid will be.It is also found that increase of relative density significantly improves interfacial friction strength,and pseudo-cohesion and friction coefficient ratio monotonically increase along with relative density while apparent friction angle changes little.Interfacial friction strength at natural water content is greater than that at saturated water content.The former has 1.28 times of the latter's pseudocohesion,while pseudo-friction angle are approximately equal.