土质边坡归一化变形量失稳判据研究

为建立土质边坡失稳的微观机理和宏观位移之间的关系,应用有限元强度折减法,分析了失稳过程中土质边坡土体单元应力状态和整体稳定性的联系,定义了边坡渐进破坏时潜在滑动面上土体单元的应力差;分别采用塑性应变区贯通、特征点位移突变、应力差等不同失稳判据对均质土坡的稳定性进行判断分析,验证了不同边坡失稳判据间的一致性与统一性。通过单因素敏感性分析方法,分析了边坡几何参数(坡高、坡比)与物理力学参数(弹性模量、重度、黏聚力、内摩擦角和泊松比等)对极限状态下边坡坡顶水平位移的影响;结合归一化变量的变异系数法,构建了以变形量为基础,同时考虑几何因素与物理因素的土质边坡归一化失稳判据,提出了边坡稳定性的评价方法。

Normalized Failure Criterion for Soil Slope Stability

In the aim of obtaining the relationship between microcosmic mechanism of soil slope instability and macroscopic displacement,a method of slope stability evaluation is proposed.The internal correlation between the soil element stress and the whole stability in the process of soil slope sliding was analyzed through shear strength reduction finite element method,and the stress difference of soil unit on the potential sliding surface during progressive failure of slope was defined.In subsequence,the consistency and uniformity among different criteria,including plastic zone penetration,abrupt change of characteristic displacement,and stress difference,were verified through instability evaluation.Furthermore,the influences of geometric and physical parameters on the horizontal displacement of slope top in limit state were analyzed through single-factor sensitivity analysis method.These parameters include slope height,slope ratio,elastic modulus,density,cohesion,internal friction angle,and Poisson ratio.Finally,the normalized failure criterion for soil slope based on deformation in consideration of both geometric and physical factors was established through the method of coefficient of variation.