软硬互层状岩体的室内单轴压缩试验及数值模拟

Uniaxial compression test and numerical simulation for alternatively soft and hard interbedded rock mass

以锦屏软硬互层状岩体为研究对象,基于室内试验分析单轴应力状态下岩样的3种破坏模式并结合数值模拟方法,分别探讨层面倾角、软弱夹层数量、分布及所占体积比等因素对互层状岩体变形特性、强度特征及破坏机制的影响。研究结果表明:锦屏互层状岩体的破坏总体遵循单轴压缩破坏的多裂纹劈裂模式,且在缓层面倾角范围内岩体的破坏以岩质材料自身属性为控制,而在较大倾角水平上则以层理弱面的影响为主导因素;软弱夹层数量对于层状岩体的U形强度规律影响不显著,但随着软弱夹层数量的增加,破坏荷载极小值有向层面倾角较小方向前移的趋势;随着软弱夹层所占体积比的增加,破坏荷载总体呈现下降趋势;当软弱夹层所占体积比接近时,软弱夹层数量的增加对岩样破坏荷载下降的影响与岩层倾角大小具有正相关关系,且当岩层水平时,对强度基本不发生影响。

For the alternatively soft and hard interbedded rock mass of JinPing Hydro-Junction project,three failure modes of rock samples under uniaxial compression stress are analyzed based on laboratory experiments,and the influence of dip angle,quantity,distribution and volume ratio of weak intercalations on the deformation property,strength characteristics and failure mechanism of rock mass are discussed by the numerical simulation.The results show that the failure of soft and hard interbedded rock mass of JinPing follows the multi-crack splitting mode of uniaxial compression failure.For the case of gentle dip angle,the failure of layered rock mass is controlled by the property of rock mass itself,while for the case of large dip angle,the influence of weak intercalations is the dominant factor.Besides,the number of weak intercalations has no significant effect on the"U"type strength characteristics of layered rock mass,but with the increase of weak intercalations,minimum value of failure load tends to move forward.With the increase of the volume ratio of the weak intercalation,the failure loading totally shows a downward trend,and when the volume ratio of weak intercalation is close in rock samples,the effect of increasing weak intercalation on the decrease of failure load is positively related to the dip angle of weak intercalations.At last,it can also be found that the increase of weak intercalations has no effect on the strength if the rock layer is horizontal.