露天矿含断层逆倾软岩边坡滑移模式及稳定性研究

作为一种典型的露天矿边坡,含断层逆倾软岩边坡变形破坏机理及稳定性问题尤为复杂。以胜利西二露天矿西帮边坡为工程背景,基于强度折减原理,应用有限差分软件FLAC3D模拟分析了Fx1断层位置、倾角及弱层逆倾角度不断变化时西帮软岩边坡的滑移模式及稳定性变化规律,阐明了边坡变形破坏机理。结果表明:逆倾软岩边坡滑坡力学机理受断层位置影响较大,当断层逐渐向边坡外侧偏移时其滑坡的力学成因由推动式滑坡逐渐过渡为牵引式滑坡,边坡稳定性逐渐提高;当断层倾角增大到某一值时,断层对逆倾软岩边坡滑移模式及稳定性影响消失;弱层倾角对滑面位置影响较大,边坡稳定性随弱层倾角减小逐渐降低;该矿西帮边坡稳定性主要受弱层控制,Fx1断层次之;当Fx1断层露头距边坡坡脚水平距离大于221 m时,边坡稳定性及滑坡模式不再受Fx1断层的控制;当Fx1断层露头距边坡坡脚水平距离小于201 m时,边坡稳定性逐渐提高,潜在滑坡模式由剪切圆弧-弱层相结合的组合滑动过渡为剪切圆弧-断层-剪切圆弧-弱层相结合的组合滑动。

Study on the sliding mode and stability of counter-dip bedded soft rock slope with fault in surface mine

The present article is inclined to dedicate itself to an investigation and analysis of the dynamic theory and its influence on the strength reduction as to the mining activities in a kind of typical surface slope through its study of the counter-dip soft rock slope with the fault due to the extremely complicated deformation failure mechanism. For the study purpose,we have made an exploration of the sliding mode and the stability of the west counterdip soft rock slope by taking the westslope of the No. 2 west surface mine in Shengli Coalfield as an engineering background with a finite difference software named FLAC3D with the change of the position. At the same time,we have also illustrated the dip angle of fault Fx1 and the weak layer reverse angle on the basis of the mechanical theory of the slope deformation and destruction. The study results demostrate that the dynamics of the landslide of the said soft rock slope has been greatly influenced by the faulty position, when the fault has been gradually slanting to the outside of the slope. In such a case,the dynamic landslide would gradually transfer from the pressing landslide back to the retrogressive landslide, thus gradually increasing the slope stability. And,then, when the fault dip increases to a certain extent,it would affect the fault part on the sliding mode and the stability of the counter-dip soft rock slope,too. Moreover,since the weak layer angle may have a great effect on the sliding position,it would gradually reduce the slope stability with the decrease of the weak layer angle. Furthermore,since the stability of the western slope of the aforementioned surface mine in the said coalfield is primarily controlled by the weak layer and the fault Fx1, the slope stability would also be consequently influenced by the fault Fx1. Furthermore, when the horizontal distance between the fault Fx1 outcrops and the slope foot increases greater than 221 m,it would be possible for the slope stability to get gradually improved due to the fact that the potential sliding mode turns to be a complicated sliding one formed by the integrated shear arc-weak layer transition to the shear arc-fault shear,whose distance between the fault Fx1 outcrops and the slope foot tends to be no greater than 201 m.