Nonlinear evolutionary mechanisms of instability of planar-slip slope:catastrophe,bifurcation,chaos and physical prediction
作者单位：Department of Earth SciencesThe University of Hong KongPokfulam RoadHong KongPeople’s Republic of China
会议名称：《中国科学院地质与地球物理研究所2006学术年会》
会议日期：2007年
学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程]
关 键 词：Cusp catastrophe Instability Stiffness ratio Homogeneity index Chaos Bifurcation Physical prediction
摘 要：A cusp catastrophe model of landslides is presented and the necessary and sufficient conditions leading to landslides are *** sliding surface is assumed to be planar and is a combination of two media:medium 1 is elastic-brittle or strain-hardening and medium 2 is *** shear stress-strain constitutive model for the strain-softening medium is described by the Weibull’s distribution *** paper is a generalization and extension of the paper by Qin et al(2001b),in which the shear stress-strain constitutive model for medium 2 was described by a negative exponent distribution,a special case of the Weibull’s distribution *** is found that the instability of the slope relies mainly on both the stiffness ratio of the media and the homogeneity index and that a new role of water is to enlarge the material homogeneity or brittleness and hence to reduce the stiffness ratio.A nonlinear dynamical model(also called a physical forecasting model),which is derived by considering the time-dependent behavior of the strain-softening medium,is used to study the time prediction of *** algorithm of inversion on the nonlinear dynamical model is suggested for seeking the precursory abnormality and abstracting mechanical parameters from the observed series of a landslide.A case study of the Jimingsi landslide is conducted and its nonlinear dynamical model is established from the observation series using the suggested model and algorithm of *** is found that the catastrophic characteristic index |D| shows a quick rise till reaching an extremely high peak value after the slope evolves into the tertiary creep,and subsequently approaches a zero value prior to instability,which can be regarded as an important precursory abnormality *** taking into account the evolutionary characteristic of the slope being in the secondary creep,a simplified nonlinear dynamical model is proposed for studying the properties of bifurcation and *** is shown t