Study On The Influence Of Weak Interlayer On The Stability Of Rock Slope

This paper firstly analyzes the influence factors of rock slope stability, then studies the basic characteristics of weak interlayer, elaborates the main destructional forms of rock slope and the mechanism of action of weak interlayer on the slope. On this basis, applies the catastrophe theory, disaster chain theory, orthogonal experiment and numerical simulation methods to the study of the rock slope with weak interlayer.1.Be aimed at the stability problem of rock slope with weak interlayer, considering the strain weakening and water-induced weakening effect of weak interlayer, established a swallowtail catastrophe model of slope with one weak interlayer, then studied the jump property of landslide of the slope based on the changes of slope potential function form.2.Applicated disaster chain theory to construct disaster chain of rock slope with weak interlayer, then discussed the ways and countermeasures for slope disaster prevention and mitigation based on the idea of "cutting the disaster chain in the headstream".3.By combining orthogonal experiment and numerical simulation, we selected 5 factors: thickness, dip, cohesion and internal friction angle of weak interlayer as well as the distance between weak interlayer and slope toe. With orthogonal design, we calculated the 16 slope models with weak interlayer and worked out the maximum displacement value in X direction and safety coefficient of each slope model. Finally, we conducted variance analysis and correlation analysis to the result and figured out the leading factors and correlative factors influencing the stability of slope. The result indicates that:thickness, dip and internal friction angle of weak interlayer have significant influences on the stability of slope. There are remarkable correlations between dip, internal friction angle and thickness of weak interlayer and the stability of slope. The bigger the dip is, the smaller the internal friction angle is and the greater the thickness is, the more easier instability and failure will occur to a slope.4.Through numerical analysis of outcropping and non-outcropping of weak interlayer from slope and the comparison between slope with weak interlayer and slope without weak interlayer, we got to know the following different instability mechanisms:in case of outcropping, it shows a progress of sliding-tension failure→collapse when the weak interlayer near the slope top; in case of non-outcropping, if the slope rock has a good lithology, it is not easy to form a perforative plastic deformation area along the interlayer; If the slope rock has a poor lithology, it is also likely to form a burst slide; If there is no weak interlayer in the slope, the overall shear strain increment of slope is small-valued and even.5.Combined with the rock slope of an open pit with weak intercalated layer, to study its stability, and proposed disaster prevention and mitigation approaches and measures in the process of mining.